CN113191327A

CN113191327A - Biological characteristic collection method, chip and computer readable storage medium

Info

Publication number: CN113191327A
Application number: CN202110574206.5A
Authority: CN
Inventors: 青小刚; 吕蒙; 袁超
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2021-05-25
Filing date: 2021-05-25
Publication date: 2021-07-30

Abstract

The embodiment of the invention relates to the technical field of biological feature detection, and discloses a biological feature acquisition method, a chip, a terminal and a computer readable storage medium. The biological characteristic acquisition method comprises the following steps: acquiring configuration parameters; wherein the configuration parameters include: the biological characteristic acquisition chip comprises a first exposure duration, a first area and a target photosensitive value, wherein the first area is a local area in a photosensitive area of the biological characteristic acquisition chip; exposing the first area according to the first exposure duration, and acquiring a photosensitive value of the first area; determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time; and acquiring the biological characteristic image according to the second exposure duration, so that the accuracy of the acquired biological characteristic image can be improved, and the accuracy of subsequent biological characteristic identification or registration is increased.

Description

Biological characteristic collection method, chip and computer readable storage medium

Technical Field

The embodiment of the invention relates to the technical field of biological feature detection, in particular to a biological feature acquisition method, a chip and a computer readable storage medium.

Background

The biometric identification technology in the interactive unlocking scheme of the terminal becomes an emerging interactive technology, wherein the optical fingerprint identification technology becomes a very convenient and fast fingerprint identification scheme. The optical fingerprint identification technology adopts a hidden fingerprint design under a screen, and a finger can unlock by directly pressing a fingerprint icon area displayed on the screen. More and more mobile phone projects of whole machine manufacturers support the optical fingerprint identification function, screens produced by different manufacturers are introduced, and the difference of the screens produced by different manufacturers is larger.

At present, in the calibration stage of the complete machine, a default exposure duration is set for the biometric feature acquisition chip in the complete machine, and when the complete machine performs biometric image acquisition based on the default exposure duration after leaving the factory, due to the change of the external environment, the adaptability of the biometric feature acquisition chip to the change of the external environment is easily deteriorated, the accuracy of the acquired biometric image is affected, and the accuracy of subsequent biometric identification or registration is reduced. Taking the under-screen fingerprint acquisition chip in the mobile phone as an example, the fluctuation of the fingerprint light spots easily causes the adaptability of the under-screen fingerprint acquisition chip to the fingerprint light spots to be deteriorated, influences the accuracy of the acquired fingerprint image, and reduces the accuracy of the subsequent fingerprint identification or registration.

Disclosure of Invention

An object of embodiments of the present invention is to provide a method, a chip, and a computer-readable storage medium for collecting biometric features, so that accuracy of collected biometric features can be improved, and accuracy of subsequent biometric feature recognition or registration can be increased.

In order to solve the above technical problem, an embodiment of the present invention provides a biometric acquisition method applied to a biometric acquisition chip, including: acquiring configuration parameters; wherein the configuration parameters include: the biological characteristic acquisition chip comprises a first exposure duration, a first area and a target photosensitive value, wherein the first area is a local area in a photosensitive area of the biological characteristic acquisition chip; exposing the first area according to the first exposure duration, and acquiring a photosensitive value of the first area; determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time; and acquiring a biological characteristic image according to the second exposure duration.

The embodiment of the invention also provides a biological characteristic acquisition chip, which comprises: the biological feature acquisition device comprises a processing unit and a storage unit connected with the processing unit, wherein the storage unit stores instructions which can be executed by the processing unit, and the instructions are executed by the processing unit so as to enable the processing unit to execute the biological feature acquisition method.

The embodiment of the invention also provides a terminal which comprises the biological characteristic acquisition chip.

Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which when executed by a processor implements the above-described biometric acquisition method.

In the embodiment of the invention, when the biological characteristic image is acquired, according to the first exposure duration in the configuration parameters, the local area (namely the first area) in the photosensitive area of the biological characteristic acquisition chip is locally exposed to obtain the photosensitive value of the first area. In consideration of the fact that the photosensitive value and the exposure time length have a preset relation, the second exposure time length required for acquiring the target photosensitive value in the photosensitive area can be reasonably and accurately determined according to the photosensitive value of the first area and the first exposure time length. That is to say, when the biometric image is acquired, the biometric image is acquired based on the second exposure duration obtained in the current environment instead of the default exposure duration in factory shipment, so that the acquired biometric image is more accurate. Even if the external environment changes, namely the current environment changes compared with the environment where the biological characteristic acquisition chip is located when the default exposure time length is determined, the second exposure time length is determined under the current environment, so that the second exposure time length can adapt to the change of the external environment, the adaptability of the biological characteristic acquisition chip to the external environment is improved, the influence of the change of the external environment on the acquisition performance is reduced, and the accuracy of subsequent biological characteristic identification or registration is improved. And because the first area is the local area in the photosensitive area, the speed of local exposure is faster, and the speed of acquiring the biological characteristic image can be accelerated to a certain extent, so that the speed of subsequently carrying out biological characteristic identification or registration can be accelerated.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

FIG. 1 is a schematic view of a fingerprint light spot as referred to in the embodiments of the present application;

fig. 2 is a flowchart of a biometric acquisition method according to an embodiment of the present application;

FIG. 3 is a schematic diagram illustrating the relationship between a first region and a photosensitive region according to an embodiment of the present disclosure;

fig. 4 is a schematic diagram of the mark information of each pixel in the first region mentioned in the embodiment of the present application;

fig. 5 is a schematic diagram of a bad block area in the first area mentioned in the embodiment of the present application;

FIG. 6 is a diagram illustrating a linear relationship between a photosensitive value and an exposure time period mentioned in the embodiment of the present application;

fig. 7 is a flowchart of another biometric acquisition method mentioned in the embodiments of the present application;

FIG. 8 is a flow chart of one implementation of step 706 mentioned in embodiments of the present application;

fig. 9 is a schematic view of the distribution of the first and second regions in the photosensitive region according to the embodiment of the present application;

FIG. 10 is a flow chart of one implementation of step 802 referred to in embodiments of the present application;

FIG. 11 is a schematic view of a striation image referred to in the examples of the present application;

FIG. 12 is a flowchart of one implementation of an embodiment of the present application that refers to capturing a biometric image according to a second exposure duration;

FIG. 13 is a flowchart of a biometric acquisition method applied to an underscreen fingerprint acquisition chip according to an embodiment of the present application;

FIG. 14 is a schematic structural diagram of a biometric acquisition chip according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present application in various embodiments of the present invention. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments. The following embodiments are divided for convenience of description, and should not constitute any limitation to the specific implementation manner of the present invention, and the embodiments may be mutually incorporated and referred to without contradiction.

Along with the high-speed development of the terminal industry, the biological characteristic acquisition technology is more and more emphasized by people, the biological characteristic acquisition chip is arranged below the screen in the under-screen biological characteristic acquisition technology, and the image of an external object is acquired through the biological characteristic acquisition chip so as to realize subsequent biological characteristic identification or biological characteristic registration. Wherein the biometric identification may include: fingerprint identification, palm print identification, iris identification, face identification and the like. Currently, an Organic Light-emitting Diode (OLED) screen and a Liquid Crystal Display (LCD) screen are a self-luminous Display screen and a non-self-luminous Display screen, respectively, which are widely applied in terminals such as mobile phones and tablet computers. The OLED screen belongs to a current-type organic light emitting device, and each display unit (also called a pixel) can be controlled by a display driving module to independently emit light.

Taking fingerprint collection as an example, the biometric acquisition chip is a fingerprint acquisition chip. The terminal that adopts the OLED screen can realize optical fingerprint collection under the screen, and the fingerprint collection chip sets up in OLED screen below, therefore this fingerprint collection chip also can be called fingerprint collection chip under the screen, and the pixel in the OLED screen can be utilized as fingerprint excitation light source to carry out the screen and polish. The pixel that is located fingerprint detection area (also known as photosensitive zone) in the OLED screen is driven and is sent out so that show a fingerprint facula at fingerprint detection area, the light of its transmission shines on the finger of OLED screen top as the excitation light that is used for fingerprint identification, and through the finger scattering, reflection or transmission back, form the fingerprint detection light that carries finger fingerprint information, this fingerprint detection light returns to the OLED screen and sees through the fingerprint collection chip that OLED screen transmitted to the below, the fingerprint collection chip can receive this fingerprint detection light and detect the light with the fingerprint and convert fingerprint detection light into corresponding signal of telecommunication, thereby realize fingerprint image collection. The schematic diagram of the fingerprint light spot can be seen in fig. 1, when a user needs to unlock the terminal 101 or verify other fingerprints, the user only needs to press a finger in an area where the fingerprint light spot 102 is located, so that fingerprint collection can be achieved, and fingerprint matching verification can be further performed based on a collected fingerprint image to complete fingerprint identification.

In the related art, in the stage of mass production of the whole terminal, a default exposure duration before factory shipment is set based on a calibration result of the whole terminal, and the default exposure duration is stored in the terminal. After the terminal leaves the factory, when a user uses the terminal to perform fingerprint registration or fingerprint identification, a fingerprint image is acquired based on the default exposure duration stored in the terminal.

The inventor of the application finds that if the fingerprint light spot fluctuates during the process of using the terminal by a user, the accuracy of fingerprint identification is easily low. Wherein, the fluctuation of the fingerprint light spot may include: brightness fluctuation, color temperature fluctuation and the like of the fingerprint light spots. The case of the fingerprint light spot fluctuating may include: due to the fact that the fingerprint facula in the complete machine calibration stage is abnormal, the set default exposure time length when leaving the factory is inaccurate; in the using process of a user, the terminal is in the environments of wallpaper switching, screen aging, software updating and the like. The inventor finds out through research that the reason that the accuracy of fingerprint identification is low due to the fluctuation of fingerprint light spots is that: after the terminal leaves the factory, in the process of being used by a user, the fingerprint image is still acquired by the under-screen fingerprint acquisition chip based on the default exposure time set during leaving the factory, the default exposure time cannot be adjusted again in the using process, so that the adaptability of the under-screen fingerprint acquisition chip to the fingerprint light spot is poor, and the accuracy of fingerprint identification is low.

In order to solve the problem that the adaptability of the above-mentioned biometric acquisition chip (such as an underscreen fingerprint acquisition chip) to the change of the external environment (such as fingerprint light spot fluctuation) is poor, and the accuracy of the acquired biometric image (such as a fingerprint image) is affected, an embodiment of the present application provides a biometric acquisition method, which is applied to a biometric acquisition chip, and includes: acquiring configuration parameters; wherein, the configuration parameters comprise: the biological characteristic acquisition chip comprises a first exposure duration, a first area and a target photosensitive value, wherein the first area is a local area in a photosensitive area of the biological characteristic acquisition chip; exposing the first area according to the first exposure duration, and acquiring a photosensitive value of the first area; determining a second exposure time required for acquiring a target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time; and acquiring a biological characteristic image according to the second exposure time. The application scenario of the embodiment may include: and (3) scenes needing biological characteristic image acquisition, such as biological characteristic identification, biological characteristic registration and the like. The biological feature recognition and the biological feature registration can be fingerprint recognition, fingerprint registration, face recognition, face registration and the like. When the biometric acquisition chip determines that biometric image acquisition is required, the biometric acquisition process in this embodiment may be triggered, i.e., the acquisition of the configuration parameters is started.

In the embodiment of the application, when the biometric image is acquired by the biometric acquisition chip, according to the first exposure duration in the configuration parameters, the local area (i.e. the first area) in the photosensitive area of the biometric acquisition chip is locally exposed to obtain the photosensitive value of the first area. In consideration of the fact that the photosensitive value and the exposure time length have a preset relation, the second exposure time length required for acquiring the target photosensitive value in the photosensitive area can be reasonably and accurately determined according to the photosensitive value of the first area and the first exposure time length. That is to say, when the biometric image is acquired, the biometric image is acquired based on the second exposure duration obtained in the current environment instead of the default exposure duration in factory shipment, so that the acquired biometric image is more accurate. Even if the external environment changes, namely the current environment changes compared with the environment where the biological characteristic acquisition chip is located when the default exposure time length is determined, the second exposure time length is determined under the current environment, so that the second exposure time length can adapt to the change of the external environment, the adaptability of the biological characteristic acquisition chip to the external environment is improved, the influence of the change of the external environment on the acquisition performance is reduced, and the accuracy of subsequent biological characteristic identification or registration is improved. And because the first area is the local area in the photosensitive area, the speed of local exposure is faster, and the speed of acquiring the biological characteristic image can be accelerated to a certain extent, so that the speed of subsequently carrying out biological characteristic identification or registration can be accelerated.

In one embodiment, the biometric acquisition chip is an off-screen fingerprint acquisition chip, and the biometric image acquired by the off-screen fingerprint acquisition chip can be used for fingerprint identification or fingerprint registration. For the terminal comprising the under-screen fingerprint acquisition chip, even in the process of the terminal actually used by a user, the condition that fingerprint light spots fluctuate on the screen of the terminal occurs, because the second exposure time duration is determined under the condition that the fingerprint light spots fluctuate, the second exposure time duration can adapt to the fluctuation condition of the fingerprint light spots, the adaptability of the under-screen fingerprint acquisition chip to the fingerprint light spots is improved, the influence of the fluctuation of the fingerprint light spots on the fingerprint identification performance is reduced, and the improvement of the fingerprint identification accuracy rate is facilitated. In a specific implementation, the biometric acquisition chip may also be an iris feature acquisition chip, a palm print feature acquisition chip, a human face feature acquisition chip, or the like.

In one embodiment, the flowchart of the biometric acquisition method may refer to fig. 2, including:

step 201: and acquiring configuration parameters.

Step 202: and exposing the first area according to the first exposure duration, and acquiring a photosensitive value of the first area.

Step 203: and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time length.

Step 204: and acquiring a biological characteristic image according to the second exposure time.

Wherein, the configuration parameters in step 201 include: the device comprises a first exposure time, a first area and a target photosensitive value, wherein the first area is a local area in a photosensitive area of a biological feature acquisition chip. The configuration parameters can be preset by those skilled in the art according to actual needs.

In one embodiment, the obtaining the configuration parameters in step 201 includes: when a preset trigger condition is detected, acquiring configuration parameters; the preset trigger condition comprises the following steps: a biometric enrollment and/or a biometric identification is required. Namely, the biological characteristic acquisition chip acquires configuration parameters when determining that biological characteristic registration and/or biological characteristic identification are/is required. The method for determining that the biometric registration is required by the biometric acquisition chip can be as follows: the biometric acquisition chip receives notification information that a user needs to perform biometric registration, and the notification information can be sent by a processor in the terminal, wherein the processor can be a Central Processing Unit (CPU), a microprocessor, a coprocessor and the like in the terminal. The terminal can be a mobile phone, a tablet computer and other devices. The mode of determining that the biological characteristics need to be identified by the biological characteristic acquisition chip can be as follows: the biological characteristic acquisition chip determines that the terminal needs to be unlocked based on biological characteristic identification, needs to pay based on biological characteristic identification and the like. Optionally, the preset trigger condition may further include: and when the biological characteristic acquisition chip detects that the biological characteristic acquisition chip is started, acquiring configuration parameters.

In one embodiment, the obtaining the configuration parameters in step 201 includes: and when the preset trigger condition is detected, acquiring the internally stored configuration parameters. After the configuration parameters are preset, the configuration parameters may be pre-stored in the biometric acquisition chip, for example, the preset configuration parameters may be written into a register of the biometric acquisition chip. That is to say, the biological characteristic acquisition chip can acquire the configuration parameters by itself, which is beneficial to quickly acquiring the configuration parameters.

In one embodiment, the obtaining the configuration parameters in step 201 includes: and receiving the configuration parameters issued by the application software in the terminal. The configuration parameters are issued by the application software, and the biological characteristic acquisition chip does not need to store the configuration parameters, so that the cost and the storage space are saved, the configuration parameters can be conveniently modified by the application software according to actual needs, and the convenience for modifying the configuration parameters is improved. Optionally, the configuration parameters issued by the application software (hereinafter, also referred to as a software end) in the receiving terminal may be: and receiving the configuration parameters issued by the software end after the preset trigger condition is detected. For example, the software end may issue the configuration parameters to the biometric acquisition chip after detecting the preset trigger condition, which is described above. And will not be described in detail herein. In a specific implementation, the biometric acquisition chip can be in a dormant state in a stage of not acquiring data, and when the biometric acquisition is required, the biometric acquisition chip is awakened, and the software end starts to issue configuration parameters.

In one embodiment, the biometric acquisition chip may store the configuration parameters in the register after receiving the configuration parameters issued by the software terminal, and when the preset trigger condition is detected again subsequently, the biometric acquisition chip may directly acquire the configuration parameters from the register in the biometric acquisition chip without being issued by the software terminal every time, which is beneficial to improving the convenience of acquiring the configuration parameters.

In one embodiment, the biometric acquisition chip is an underscreen fingerprint acquisition chip, and the biometric enrollment and/or biometric identification includes: the area where the fingerprint light spot on the screen is detected to be pressed is preset for a time length which is greater than or equal to the minimum time length required for the fingerprint light spot to be lightened until the fingerprint light spot is stable. The obtaining of the configuration parameters in step 201 includes: and when the area where the fingerprint light spot on the screen is detected to be pressed, acquiring the configuration parameters at preset time intervals. The minimum time required for the fingerprint light spot to start to be lighted until the fingerprint light spot is stable can be obtained by testing according to actual needs by those skilled in the art, and for example, the minimum time can be set to 40ms to 50ms, which is not specifically limited in this embodiment. When the area where the fingerprint light spot on the screen is detected to be pressed, the area can be understood as the area where the fingerprint light spot on the screen is pressed, and the fingerprint acquisition chip under the screen determines that fingerprint identification or fingerprint registration is required currently. The configuration parameters are acquired again after the interval preset time length is achieved, the configuration parameters are acquired again by the fingerprint acquisition chip under the screen after the fingerprint light spots displayed on the screen are ensured to be stable, and then the subsequent second exposure time length is calculated based on the configuration parameters, so that the second exposure time length is acquired after the fingerprint light spots are stable, the accuracy of the acquired second exposure time length is improved, the accuracy of the acquired fingerprint image can be improved, and the accuracy of the subsequent fingerprint identification or fingerprint registration is improved.

In one embodiment, the under-screen fingerprint acquisition chip may send the information of detecting that the area where the fingerprint spot is located is pressed to the software end, the software end starts timing when receiving the information of being pressed, and after the timing reaches a preset time, the software end sends the configuration parameters to the under-screen fingerprint acquisition chip, so that the under-screen fingerprint acquisition chip may acquire the configuration parameters at a preset time interval after detecting that the area where the fingerprint spot on the screen is located is pressed. Configuration parameters are issued by a software end, and the configuration parameters do not need to be stored by the under-screen fingerprint acquisition chip, so that the cost and the storage space are saved. And after the interval preset time length, the software end sends the configuration parameters to the fingerprint acquisition chip under the screen, so that the second exposure time length is acquired after the fingerprint facula is stable, the accuracy of the acquired second exposure time length is improved, the accuracy of the acquired fingerprint image can be improved, and the accuracy of subsequent fingerprint identification or fingerprint registration is improved.

In an embodiment, the off-screen fingerprint acquisition chip may start timing when detecting that the area where the fingerprint light spot is located is pressed, and obtain the configuration parameters stored in the register in advance from the register of the off-screen fingerprint acquisition chip after the timing reaches a preset time length, so that the off-screen fingerprint acquisition chip may obtain the configuration parameters at intervals of the preset time length after detecting that the area where the fingerprint light spot is located on the screen is pressed. The under-screen fingerprint acquisition chip can acquire the configuration parameters by itself without interaction with a software end, and is favorable for rapidly acquiring the configuration parameters, and after the interval preset time is long, the under-screen fingerprint acquisition chip acquires the configuration parameters again, so that the second exposure time is acquired after the fingerprint light spots are stable, the accuracy of the acquired second exposure time is improved, the accuracy of the acquired fingerprint image can be improved, and the accuracy of subsequent fingerprint identification or fingerprint registration is improved.

In one embodiment, the first exposure time period (denoted as T1) may be determined according to the linearity of the biometric acquisition chip, and the smaller the linearity, the smaller the determined first exposure time period. The linearity is an important index for describing the biological characteristic acquisition chip, and the smaller the linearity is, the better the linearity is, namely the more accurate the linearity is. The better the linearity, the shorter T1 can be set, the worse the linearity, and the longer T1 can be set. The inventor finds out through research that: the linearity of the biometric acquisition chip can affect the accuracy of the light intensity estimated based on the acquired light sensitivity value within the same exposure time, and the estimated accuracy of the light intensity can further affect the accuracy of the acquired biometric image. Therefore, in the embodiment, the first exposure time length is determined according to the linearity of the biometric feature acquisition chip, and the smaller the linearity is, the smaller the determined first exposure time length is, which is beneficial to improving the accuracy of the acquired biometric feature image to a certain extent, so that the accuracy of subsequent biometric feature identification or registration is improved.

In one embodiment, the first exposure time period may be further determined according to the linearity of the biometric acquisition chip and a standard time period preset for completing fingerprint recognition. The standard time required for completing the biometric recognition may also be referred to as: the Key Performance Indicator (KPI) time. The KPI time can be set by technical personnel in the art according to actual need, for example, when the requirement for discerning speed is higher, the KPI time can be set shorter, when the requirement for discerning speed is lower, the KPI time can be set longer, the setting of KPI time can satisfy the requirement for discerning speed under the different discernment scenes. The larger the KPI time, the longer T1 can be set, and the smaller the KPI time, the shorter T1 can be set. Finally, the KPI time and the linear characteristic can be considered together to determine the size of T1, wherein T1 is more than 0 millisecond. The inventor finds out through research that: the length of the first exposure period T1 affects KPI time, and the larger the T1, the larger the effect on recognition speed. Therefore, in the embodiment, the first exposure time determined according to the KPI time and the linearity of the biometric acquisition chip is beneficial to balancing the recognition speed and the recognition accuracy, and the recognition accuracy can be ensured to a certain extent while the biometric recognition can be completed within the standard time.

In one embodiment, the first exposure time period is greater than 0 milliseconds and less than or equal to 10 milliseconds. That is to say, the value range of the first exposure time length T1 is between 0 and 10 milliseconds, and the value of T1 is small, which is beneficial to shortening the time for completing the biometric acquisition, so that the time for performing the biometric identification or registration subsequently can be shortened. In a specific implementation, the larger the value of T1, the more accurate the determined T2, and thus the more accurate the acquired biometric image, within a certain range (e.g., between 0 and 10 milliseconds).

In one embodiment, the first exposure time period T1 is determined according to the KPI time and the linearity of the biometric acquisition chip, and 0ms < T1 ≦ 10 ms. That is to say, T1 selects one from 0ms and 10ms to 10ms according to KPI time and the linearity of the biological characteristic acquisition chip, which is beneficial to accelerating the acquisition speed as much as possible and simultaneously ensuring that the accuracy of acquisition is not influenced.

In one embodiment, the biometric acquisition chip is arranged below the screen, the area of the first area is determined according to the structure of the screen, and the structure of the screen is a soft screen or a hard screen. The area of the first region determined based on the soft screen is larger than the area of the first region determined based on the hard screen. That is, the soft screen is larger than the first area of the hard screen. The soft screen is because the center sinks, compare in the area that the first region that hard screen was got bigger, soft screen center sinks to make the sensitization value that the pixel that is located soft screen center gathered to be slightly little, consequently gets great first region, makes the sensitization value that the pixel that can combine in great first region gathered, acquires the sensitization value in first region, is favorable to adapting to the demand of different screen types to first region size, improves the accuracy of the sensitization value of gathering after carrying out the local exposure.

In one embodiment, referring to fig. 3, the center of the first region 301 is the light-gathering center 303 of the photosensitive region 302. The focus center 303 may be understood as the projection point of the center of the lens assembled with the biometric acquisition chip in the photosensitive area 302. It will be appreciated that assembly tolerances may exist during assembly of the biometric acquisition chip with the lens such that the center of the lens does not completely coincide with the center of the photosensitive region in the biometric acquisition chip in the vertical direction. Therefore, the first region 301 is a region centered on the light-gathering center of the light-sensing region, and the light-sensing values collected by the pixels in the first region centered on the light-gathering center are concentrated and have small differences, which is beneficial to improving the accuracy of the obtained light-sensing values of the first region. However, in a specific implementation, the center of the first region may also be directly the center of the photosensitive region.

In one embodiment, the area of the first region determined based on the soft screen is larger than the area of the first region determined based on the hard screen, and the centers of the first regions in the soft screen and the hard screen are both the light-gathering centers of the photosensitive regions, which is beneficial to further improving the accuracy of the acquired photosensitive values of the first region while meeting the requirements of different screen types on the size of the first region.

In a specific implementation, it is considered that the larger the first region is, the more accurate the light intensity detection is, but the larger the first region is to a certain extent, the accuracy of the light intensity detection is not increased any more, and meanwhile, the larger the first region is, the longer the time required for acquiring the biometric image is. Therefore, the size of the first region can be determined through simulation, for example, the size of the first region can be gradually increased in the simulation process, the accuracy of light intensity detection and the time required for acquiring a biological characteristic image after the first region is increased each time are determined, and a compromise value is taken for the first region according to the accuracy of light intensity detection and the time required for acquiring the biological characteristic image, so that the determined first region can ensure that the time for acquiring the biological characteristic image is not too long, and the accuracy of light intensity detection is not greatly influenced.

In one embodiment, the number of pixels in the first region is an integer multiple of the number of pixels to be read out in a one-pixel mode determined based on the image readout mode binning of the biometric acquisition chip. For example, the image reading mode binning of the biometric acquisition chip is 2 × 2, that is, the number of pixels to be read in the mode of one pixel is 4, and the number of pixels in the first region is an integer multiple of 4. For example, the image readout mode binning of the biometric acquisition chip is 4 × 4, that is, the number of pixels to be read out in a one-pixel mode is 16, and the number of pixels in the first region is an integer multiple of 16. The selection of the first region takes the image reading mode binning of the biological characteristic acquisition chip into consideration, so that the subsequent processing of pixels in the first region based on binning is facilitated, the self image reading mode of the biological characteristic acquisition chip is favorably adapted, and the speed of image reading is improved, namely the speed of acquiring biological characteristic images is improved.

In one embodiment, the first region is a rectangular region, such as rectangular region 301 in fig. 3, which may be represented by coordinates (x0, y0) (x1, y1) of two points A, B in the figure. It is understood that a pixel array including a plurality of pixels is distributed in the photosensitive region 302, the pixel a is located at row x0 and column y0 in the pixel array, and the pixel B is located at row x1 and column y1 in the pixel array. If the configuration parameter of the first area is issued by the software end, the software end may directly send coordinates of boundary points of the first area, for example, coordinates of A, B points in fig. 3, which may reduce the amount of data issued and increase the issuing speed. If the configuration parameter of the first area is pre-stored in the biological characteristic acquisition chip, the biological characteristic acquisition chip can store the coordinates of the boundary point of the first area, so that the amount of stored data can be reduced, and the storage space is saved.

In one embodiment, the first region may also be represented by marking information of pixels in the entire photosensitive region, such as: the pixels in the first region 301 are all labeled as "X", the pixels in the photosensitive region 302 except the pixels in the first region 301 are labeled as "Y", and the pixels in the entire photosensitive region can be represented as an array composed of "X" and "Y", and the region formed by "X" in the array is the first region 301. If the configuration parameter of the first area is issued by the software end, the software end can directly send the array consisting of the X and the Y, so that the biological characteristic acquisition chip can clearly distinguish the first area in the photosensitive area directly according to the received array consisting of the X and the Y. If the configuration parameter of the first area is pre-stored in the biological characteristic acquisition chip, the biological characteristic acquisition chip can store the array consisting of the X and the Y, so that the biological characteristic acquisition chip can clearly distinguish the first area in the photosensitive area directly according to the stored array consisting of the X and the Y.

In one embodiment, the biological characteristic acquisition chip is arranged below the screen, the target photosensitive value is determined based on a gain value corresponding to the structure of the screen, the structure of the screen is a soft screen or a hard screen, and the gain value corresponding to the soft screen is larger than the gain value corresponding to the hard screen. The Target photosensitive value is marked as Target, the Gain value is marked as Gain, the Gain can represent the amplification factor of the signal, the Gain and the Target have a preset corresponding relationship, and the corresponding relationship can be set by a person skilled in the art according to actual needs. In a specific implementation, the Gain value Gain of the screen may be stored in a register of the biometric acquisition chip. In this embodiment, it is considered that the transmittance of the soft screen is generally lower than that of the hard screen, and therefore, the gain value corresponding to the soft screen is set to be greater than that corresponding to the hard screen, which is beneficial to ensuring that the soft screen and the hard screen can have the same target photosensitive value, and is convenient for the processing of the biological characteristic acquisition chip, so that the biological characteristic acquisition chip can maintain one set of algorithm and is compatible with the soft screen and the hard screen, and the compatibility and the applicability of the biological characteristic acquisition chip are beneficial to being improved.

In step 202, the photosensitive value of the first area may be understood as the photosensitive value collected by the pixel located in the first area. Specifically, the light sensing value of the first region may be: and acquiring a photosensitive value acquired by a pixel meeting a preset condition in the first area. The preset conditions can be set according to actual needs, and several forms of the preset conditions are described below:

optionally, the preset condition may be any one of the following conditions: one or more pixels in the first area at random, a pixel located at the center of the first area, all pixels in the first area.

Optionally, the preset condition may be: pixels in the first region that do not belong to a dead pixel. The above-mentioned dead spots can include two major categories: one is bad spots due to process limitations; the other is a pixel (CF dot for short) with a Color Filter (CF) disposed above. The two kinds of dead pixels can be tested in a complete machine testing stage before delivery and stored in the complete machine, and the complete machine can be a mobile phone, a tablet personal computer and other terminals. Considering that a pixel provided with CF may actually receive only red light, only green light, or only blue light, the pixel provided with CF only receives light of a certain wavelength band compared with other pixels not provided with CF, and the pixel provided with CF has different light sensitivity compared with other surrounding pixels not provided with CF, which may cause some interference on the finally acquired biometric image. Therefore, the pixel provided with the CF is also regarded as a pixel belonging to a dead pixel in the present embodiment.

Under the preset conditions: in the case of a pixel in the first region that does not belong to a dead pixel, the configuration parameters include, in addition to the first exposure time, the first region, and the target exposure value described above: for determining the reference information of the first type pixels belonging to the dead pixel in the first area, the step 202 of obtaining the photosensitive value of the first area may include: and acquiring the photosensitive value acquired by the second type of pixels except the first type of pixels in the first area according to the reference information. That is, the biometric acquisition chip may acquire the sensed light values acquired by the pixels in the first region that do not belong to the dead pixel. The difference of the photosensitive value acquired by the dead pixel is larger than that acquired by the normal pixel, and the photosensitive value acquired by the pixel which does not belong to the dead pixel in the first area is acquired, so that the accuracy of the acquired photosensitive value of the first area is improved, and the accuracy of the subsequently determined second exposure time is improved.

In one embodiment, the reference information includes: label information for each pixel in the first region, the label information comprising: the biological characteristic acquisition chip can determine the first type of pixels belonging to the dead pixel as the pixels marked with the first marking information according to the reference information and then acquire the photosensitive value acquired by the second type of pixels in the first area, wherein the second type of pixels do not belong to the dead pixel. The first flag information and the second flag information may be set according to actual needs, for example: the first flag information is represented by "0", that is, the first type pixel belonging to the dead pixel is marked as "0", the second flag information is represented by "1", that is, the normal pixel (also referred to as the second type pixel) not belonging to the dead pixel is marked as "1", and fig. 4 can be referred to for a schematic diagram of the flag information of each pixel in the first area. If the configuration parameter of the reference information is issued by the software end, the software end can directly send the marking information of each pixel in the first area, so that the biological characteristic acquisition chip can clearly distinguish whether each pixel belongs to a dead pixel or not according to the marking information of each pixel. If the configuration parameter of the reference information is stored in the biological characteristic acquisition chip, the biological characteristic acquisition chip can store the array shown in fig. 4, so that the biological characteristic acquisition chip can clearly distinguish whether each pixel belongs to a dead pixel according to the stored array.

In another embodiment, the reference information includes: based on the coordinate information of the bad block area determined by the first type of pixels belonging to the bad point, the biological characteristic acquisition chip can determine the first type of pixels belonging to the bad point in the first area as the pixels in the bad block area according to the reference information. The bad block area may be a minimum rectangular area formed by the first type of pixels belonging to the bad point, so that the coordinate information of the bad block area may be directly represented by the coordinate information of the boundary point of the bad block area, and the data size of the reference information is relatively small. For example, fig. 5 may be referred to as a schematic diagram of a bad block region in the first region, and a region outlined by a dashed line in fig. 5 is the bad block region. As can be seen from fig. 5, since the bad block area appears as a regular rectangular area, the existence of the pixel points that do not belong to the bad pixel in the bad block area is allowed, for example, two normal pixels marked as "1" exist in the bad block area in fig. 5. The biological characteristic acquisition chip can regard the pixels in the bad block area as the first type of pixels belonging to the bad point, and the existence of individual normal pixels in the bad block area can not cause great influence on the subsequent processing. If the configuration parameter of the reference information is issued by the software end, the software end can directly send the coordinate information of the bad block area, the issued data volume can be reduced, and the issuing speed is increased. If the configuration parameter of the reference information is pre-stored in the biological characteristic acquisition chip, the biological characteristic acquisition chip can store the coordinate information of the bad block area, so that the stored data volume can be reduced, and the storage space is saved.

In one embodiment, step 202 may be: after the biological characteristic acquisition chip detects the preset trigger condition, exposing the first area according to the first exposure duration after the preset duration, and acquiring a photosensitive value of the first area. After the interval preset time is long, local exposure is performed again, so that the biological characteristic acquisition chip can be in a relatively stable state during the local exposure, the second exposure time is acquired in the relatively stable state, the accuracy of acquiring the second exposure time is improved, and the accuracy of the acquired biological characteristic image can be improved.

For example, the biometric acquisition chip is a fingerprint acquisition chip under the screen, and when the fingerprint acquisition chip under the screen detects that the area where the fingerprint light spot on the screen is located is pressed, the configuration parameters can be acquired first, after the area where the fingerprint light spot on the screen is detected to be pressed, the first area is exposed according to the first exposure duration at intervals of a preset duration, and the light sensing value of the first area is acquired. After the area at the fingerprint facula on the screen was pressed, the fingerprint facula began to be lighted, and the interval is defaulted the fingerprint facula after presetting for a long time and is stable, promptly after the fingerprint facula is stable, begins again to expose first region. In a specific implementation, the under-screen fingerprint acquisition chip may also start to acquire the configuration parameters after detecting that the area where the fingerprint light spot on the screen is located is pressed for a preset time interval, and then perform the step of exposing the first area.

In step 203, in consideration of a preset relationship between the exposure value and the exposure duration, a second exposure duration required for acquiring the Target exposure value in the photosensitive region may be determined by combining the preset relationship, where the preset relationship may be a linear relationship between the exposure value and the photosensitive value, for example, referring to a linear relationship between the exposure value and the photosensitive value in fig. 6, and the second exposure duration T2 may be calculated by combining the linear relationship, the photosensitive value Rawdata of the first region, the Target exposure value Target, and the first exposure duration T1.

In one embodiment, if the exposure value of the first area obtained in step 202 is: if the light exposure value acquired by one pixel meets the preset condition, the biological feature acquisition chip may directly use the light exposure value acquired by the pixel meeting the preset condition as the light exposure value (denoted as Rawdata) of the first region, and then calculate T2 according to the Rawdata, T1, Target, and the linear relationship shown in fig. 6.

In one embodiment, if the exposure value of the first area obtained in step 202 is: and sorting the photosensitive values acquired by the plurality of pixels meeting the preset condition from small to large by the biological characteristic acquisition chip, and selecting one photosensitive value in a preset range as the photosensitive value of the first area according to the arrangement sequence of the photosensitive values. Then, from the selected photo-value, T1, Target, and the linear relationship shown in fig. 6, T2 is calculated. The preset range does not include the photosensitive value arranged at the front N bit, nor the photosensitive value arranged at the back N bit, N is an integer greater than 1, and the specific value of N may be set by a person skilled in the art according to actual needs, which is not specifically limited in this embodiment. Considering that the photosensitive value arranged at the front N bit and the photosensitive value arranged at the back N bit may belong to abnormal photosensitive values, selecting one photosensitive value in the preset range as the photosensitive value of the first region can avoid the interference of the abnormal photosensitive value to the photosensitive value of the first region, and is beneficial to improving the accuracy of the determined photosensitive value of the first region, thereby improving the accuracy of the calculated T2.

In one embodiment, if the photo-sensitivity value of the first region obtained in step 202 is the photo-sensitivity value collected by a plurality of pixels meeting the preset condition, the biometric acquisition chip may average the photo-sensitivity values collected by the plurality of pixels meeting the preset condition to obtain a pixel average value of the first region, and the pixel average value is used as the photo-sensitivity value of the first region. Then, from the pixel average, T1, Target, and the linear relationship shown in fig. 6, T2 is calculated. The average value of the photosensitive values acquired by the pixels is used as the photosensitive value of the first area, so that the interference caused by inaccurate photosensitive values acquired by individual pixels is reduced, the determined photosensitive value of the first area is more accurate and reasonable, and the accuracy of the T2 obtained by calculation is improved.

In step 204, acquiring the biometric image according to the second exposure duration may be understood as: the biological characteristic acquisition chip exposes the photosensitive area of the biological characteristic acquisition chip at T2, acquires the photosensitive value of the photosensitive area and obtains a biological characteristic image based on the photosensitive value.

In this embodiment, the biometric characteristic collection method may be understood as using an Automatic Exposure Control (AEC) mode, and the value of the first Exposure time duration is short, so that when it is determined that biometric characteristic identification or registration is required, according to configuration parameters, the first region is automatically subjected to short Exposure, and a photosensitive value of the first region is obtained, and then, in combination with a linear relationship between the photosensitive value and the Exposure time duration, a second Exposure time duration T2 is determined by a linear fitting mode, and a biometric characteristic collection chip is configured to expose the photosensitive region by T2, so as to obtain a biometric characteristic image. The second exposure duration is determined by short exposure of the local area under the current environment, so that the second exposure duration can adapt to the change of the external environment, the adaptability of the biological feature acquisition chip to the external environment is improved, the influence of the change of the external environment on the acquisition performance is reduced, and the accuracy of subsequent biological feature identification or registration is improved.

In one embodiment, the configuration parameters include, in addition to the first exposure time, the first area, the target photosensitive value, and the reference information: a filter coefficient; after acquiring the photosensitive value acquired by the second type of pixels in the first area except the first type of pixels according to the reference information, the method further comprises the following steps: taking the filling photosensitive value as a photosensitive value collected by the first type of pixels; the filling photosensitive value is a photosensitive value collected by a second type of pixel around the first type of pixel; filtering the photosensitive value acquired by the first type of pixels and the photosensitive value acquired by the second type of pixels according to the filter coefficient to obtain filtered photosensitive values; determining a second exposure time length required for acquiring a target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time length, wherein the second exposure time length comprises the following steps: and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value and the first exposure time length. Fig. 7 may be referred to as a flowchart of the biometric acquisition method in this embodiment, and includes:

step 701: and acquiring configuration parameters.

Step 702: and determining the first type of pixels belonging to the dead pixel in the first area according to the reference information.

Step 703: and exposing the first area according to the first exposure duration to obtain the photosensitive value acquired by the second type of pixels except the first type of pixels in the first area.

Step 704: taking the filling photosensitive value as a photosensitive value collected by the first type of pixels; and the filling photosensitive value is the photosensitive value collected by the second type of pixels around the first type of pixels.

Step 705: and filtering the photosensitive value acquired by the first type of pixels and the photosensitive value acquired by the second type of pixels according to the filter coefficient to obtain a filtered photosensitive value.

Step 706: and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value and the first exposure time length.

Step 707: and acquiring a biological characteristic image according to the second exposure time.

Step 701 is similar to step 201, and the main difference is that the configuration parameters in step 701 include, in addition to the first exposure duration, the first area, and the target exposure value: reference information and filter coefficients for determining pixels of a first type in the first region that belong to the dead pixel. The reference information has been already described above and is not described in detail herein, and the filter coefficients can be set by those skilled in the art according to actual needs.

In one embodiment, the biological characteristic acquisition chip is arranged below the screen, and the filter coefficient is determined according to the structure of the screen; the screen is in a soft screen or hard screen structure, and the filter coefficient determined based on the hard screen is larger than the filter coefficient determined based on the soft screen. The inventor finds out through research that: different screen structures have differences in the degree of influence on the photosensitive value acquired by the pixel, that is, upward burrs formed on different screen structures by the biological characteristic image have differences, so that the filter coefficient determined according to the structure of the screen in the embodiment is more targeted, and the photosensitive value can be filtered more reasonably, thereby reducing the influence of different screen structures on the photosensitive value acquired by the pixel, and further improving the accuracy of the determined second exposure time.

Optionally, it is considered that different assembly tolerances of the biometric acquisition chip during assembly ultimately affect the degree of the photosensitive value acquired by the pixel. Therefore, in this embodiment, the filter coefficient may be determined according to the structure of the screen and the assembly tolerance of the biometric feature acquisition chip, and the photosensitive value may be filtered with a more reasonable filter coefficient, so as to reduce the influence of different screen structures and assembly tolerances on the photosensitive value acquired by the pixel to the maximum extent, so as to further improve the accuracy of the determined second exposure duration. Wherein, the assembly tolerance is mainly embodied in the error of the object distance P and/or the error of the image distance Q of the lens after the biological characteristic acquisition chip is assembled with the lens, and the error of the object distance P can be understood as: the difference between the object distance P after assembly and the preset standard object distance, the error of the image distance Q can be understood as: and the difference between the image distance Q after assembly and the preset standard image distance. When the error of the object distance P and/or the error of the image distance Q are large, the spur is also emphasized, and a large filter coefficient is required to filter the spur. That is, the larger the assembly tolerance, the larger the determined filter coefficient may be, thereby filtering out the glitch. In a specific implementation, the filter coefficients may also be dynamically adjusted according to actual needs to achieve a better filtering level. The preset standard object distance and the preset standard image distance may be set according to actual needs, which is not specifically limited in this embodiment.

In step 702, if the reference information is: label information for each pixel in the first region, the label information comprising: the first marking information used for representing that the pixel belongs to the dead pixel and the second marking information used for representing that the pixel does not belong to the dead pixel, and the first type of pixel which belongs to the dead pixel in the first area and is determined by the biological characteristic acquisition chip according to the reference information is as follows: pixels marked with first marking information. If the reference information is the coordinate information of the bad block area determined based on the first type of pixels belonging to the bad point, the biological characteristic acquisition chip determines that the first type of pixels belonging to the bad point in the first area are as follows according to the reference information: pixels in the bad block region.

In step 703, the biometric acquisition chip exposes the first region according to the first exposure duration to obtain a photosensitive value acquired by the second type of pixels in the first region, except the first type of pixels, that is, to obtain a photosensitive value acquired by the normal pixels in the first region.

In step 704, the biometric acquisition chip may fill the first type of pixel with the sensed values acquired by the second type of pixels surrounding the first type of pixel, that is, fill the dead pixel with the sensed values acquired by the normal pixels surrounding the dead pixel, and set the sensed values acquired by the pixels belonging to the dead pixel as the sensed values acquired by the normal pixels surrounding the dead pixel. Wherein, the normal pixels around the dead pixel may be the normal pixels closest to the dead pixel position.

In step 705, the biometric acquisition chip filters the sensed light values acquired by the first type of pixels and the sensed light values acquired by the second type of pixels according to the filter coefficients to obtain filtered sensed light values. Namely, the biological characteristic acquisition chip filters the photosensitive values acquired by all the pixels in the first area to obtain the filtered photosensitive values. Wherein, when filtering, the filtering mode that can adopt is: median filtering, gaussian low-pass filtering, etc., however, this embodiment is not limited to this specifically, and other filtering methods may also be used in the specific implementation.

In the embodiment, the photosensitive value acquired by the dead pixel, namely the first-class pixel, is replaced by the photosensitive value acquired by the normal pixel points around the dead pixel, so that the subsequent integral filtering of the photosensitive values of all the pixels in the first area is conveniently performed according to the filtering coefficient, the phenomenon that the filling is not performed due to the removal of the dead pixel and the mutation of the photosensitive value caused after the direct filtering is avoided, the filtered photosensitive value can better reflect the real perception of the pixel on an optical signal from the outside, the second exposure duration determined by combining the filtered photosensitive value can better adapt to the change of the outside environment, the adaptability of the biological characteristic acquisition chip to the outside environment is better, the influence of the change of the outside environment on the acquisition performance is reduced, and the subsequent accuracy of biological characteristic identification or registration is improved. For the collection of the fingerprints under the screen, the optical signal from the outside can be understood as excitation light for fingerprint collection, which is irradiated onto the finger above the screen and forms fingerprint detection light carrying fingerprint information after being scattered, reflected or transmitted by the finger.

In step 706, determining a second exposure duration required for acquiring the sensed light value in the sensing region according to the filtered sensed light value and the first exposure duration may include: and averaging the photosensitive values of the pixels after filtering in the first area to obtain a pixel average value of the first area, and taking the pixel average value as the photosensitive value of the first area. Then, from the pixel average, T1, Target, and the linear relationship shown in fig. 6, T2 is calculated.

In one embodiment, the implementation of step 706 can refer to fig. 8, including:

step 801: and acquiring a photosensitive value of the second area.

Step 802: and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value, the photosensitive value of the second area and the first exposure time length.

The second area is an edge area of the photosensitive area, the edge area is an area used for detecting circuit noise of the biological characteristic acquisition chip, and the second area is not overlapped with the first area. The circuit noise may be understood as noise of a circuit in the biometric acquisition chip, and the circuit in the biometric acquisition chip may include: gain circuits, analog-to-digital conversion circuits, and the like. A schematic distribution of the first and second regions in the photosensitive region may be found in fig. 9, where fig. 9 shows the photosensitive region 302 including: a second region 901 located at the peripheral edge of the photosensitive region 302 and a non-Dark region 902 surrounded by the second region 901, the first region 301 being located in the non-Dark region 902.

The edge area of the light sensing area of the biological characteristic acquisition chip can be shielded by shielding materials, and external light is not easy to feel. The shielding material may be metal, that is, the edge area of the photosensitive area is covered by metal, and the area covered by metal may be referred to as a second area, and may also be referred to as a Dark area, a metal covered area, or a black-covered area. The pixels in the second area generally do not receive the ambient light because they are covered by the metal, but when the second area is illuminated by the strong light, the strong light may penetrate through the metal covering the second area, so that the pixels in the second area may receive some ambient light when the second area is illuminated by the strong light. The light-sensitive values acquired by the pixels in the second area can be understood as: under the current environment, the light sensing value collected by the pixel when not being sensed is called the Dark value for short, so the Dark value can be used to represent the reference value collected by the pixel under the condition of no illumination, and the reference value can be used to represent the magnitude of the circuit noise. In the case of illumination, the sensitization value acquired by a pixel minus the Dark value can represent: and removing the photosensitive value actually acquired by the pixel after the reference, namely removing the circuit noise. The photosensitive value after the reference removal can eliminate the influence of circuit noise, and can more accurately reflect the light signal from the outside sensed by the pixel.

In one embodiment, step 801 may be: and acquiring the photosensitive value acquired by the pixel at the non-edge of the second area. The inventor finds that, although the pixels in the second region are generally not easy to feel the external light, the pixels in the second region are still easy to be interfered by the external strong light, and especially the pixels in the edge region of the second region are more likely to be interfered by the strong light. Therefore, in this embodiment, when the photosensitive value of the second area is obtained, the photosensitive value acquired by the non-edge pixel in the second area is obtained, so that in the current environment, the determined Dark light interference can be eliminated, the photosensitive value acquired by the non-photosensitive pixel can be more accurately reflected, and the accuracy of the determined second exposure time duration is improved.

In one embodiment, step 801 may be: and acquiring a photosensitive value acquired by a middle a column pixel and/or a middle a row pixel of the second area, wherein a is an integer greater than or equal to 1. For example, referring to fig. 9, the second region 901 is distributed around the peripheral edge of the photosensitive region 302, and then the second region 901 may include: subregion 1 at the left edge of the photosensitive region 302, subregion 2 at the right edge of the photosensitive region 302, subregion 3 at the upper edge of the photosensitive region 302, subregion 4 at the lower edge of the photosensitive region 302. The middle a-column pixels and/or the middle a-row pixels of the second region may comprise any one or a combination of the following: the pixels in the middle a columns of the sub-area 1, the pixels in the middle a columns of the sub-area 2, the pixels in the middle a rows of the sub-area 3, and the pixels in the middle a rows of the sub-area 4. For example, 13 columns of pixels are shared in the sub-area 1, the middle a column of pixels in the sub-area 1 may be the middle 8 columns of pixels in the sub-area 1, wherein originally 2 columns of the left edge and 3 columns of the right edge of the sub-area 1 may be removed from the 13 columns of pixels, so as to leave the middle 8 columns of pixels, and then the Dark value acquired by the middle 8 columns of pixels in the sub-area 1 is acquired. The middle a-column pixels and/or the middle a-row pixels in the second area are far away from the edge of the second area, and the data are concentrated, so that the accuracy of a reference value, namely a Dark value, which is used for representing that the pixels can acquire under the condition of no illumination can be improved while strong light interference is avoided, and the accuracy of the determined second exposure time length is improved.

In step 802, the filtered exposure value may be: and filtered photosensitive values corresponding to the pixels in the first area. When the second exposure time required for acquiring the Target photosensitive value in the photosensitive area is determined according to the filtered photosensitive value, the photosensitive value of the second area and the first exposure time, one of the filtered photosensitive values corresponding to the pixels in the first area may be selected as Rawdata1, one of the filtered photosensitive values acquired by the pixels in the second area may be selected as Dark1, and then T2 is calculated according to the Rawdata1, Dark1, T1 and Target. For example, T2 may be calculated by the following formula:

the selection mode of the Rawdata1 can be as follows: and sorting the filtered photosensitive values corresponding to the pixels in the first area from small to large, and selecting one of the filtered photosensitive values as Rawdata1 in a preset range according to the arrangement sequence of the filtered photosensitive values. The preset range does not include the filtered photosensitive value arranged at the front N bit, nor the filtered photosensitive value arranged at the back N bit, N is an integer greater than 1, and a specific value of N may be set by a person skilled in the art according to actual needs, which is not specifically limited in this embodiment. The Dark1 may also be selected in a similar manner and will not be described again to avoid repetition. Considering that the photosensitive value arranged at the front N bit and the filtered photosensitive value arranged at the rear N bit may belong to abnormal photosensitive values, selecting one of the photosensitive values within the preset range as Rawdata1 can avoid calculating T2 through the abnormal photosensitive value, which is beneficial to improving the accuracy of the determined T2. In this embodiment, when the T2 is calculated, since the filtered sensitization value Rawdata1 corresponding to a certain pixel in the first region and the Dark1 collected by a certain pixel in the second region are selected, the data processing process is simple, and the T2 can be obtained quickly, so that the recognition speed is increased.

In one embodiment, the implementation of step 802 can be referred to fig. 10, including:

step 1001: and determining the average photosensitive value of the first area according to the filtered photosensitive value.

Step 1002: and determining the average photosensitive value of the second area according to the photosensitive values acquired by the pixels in the second area.

Step 1003: and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the average photosensitive value of the first area, the average photosensitive value of the second area and the first exposure time length.

In step 1001, the biometric acquisition chip may average the filtered light sensitivity values corresponding to the pixels in the first region to obtain an average light sensitivity value of the first region. Optionally, the biological feature acquisition chip may also sequence the filtered photosensitive values corresponding to the pixels in the first region from small to large, and average the filtered photosensitive values within a preset range to obtain an average photosensitive value of the first region. The preset range does not include the filtered photosensitive value arranged at the front N bits, nor the filtered photosensitive value arranged at the back N bits, and N is an integer greater than 1.

In step 1002, the biometric acquisition chip may average the light sensitivity values acquired by the pixels in the second area to obtain an average light sensitivity value of the second area. Wherein, the light sensing values collected by the pixels in the second area may include: the sensed values collected by pixels at the non-edge of the second region. Alternatively, the light sensing values collected by the pixels in the second region may include: and the photosensitive value collected by the middle a-column pixel and/or the middle a-row pixel of the second area.

In step 1003, the average light sensation value of the first region is denoted as Rawmean, and the average light sensation value of the second region is denoted as Darkmean, and then the second exposure time period T2 may be calculated by the following formula:

in this embodiment, the average photosensitive value of the first region may represent the average level of the photosensitive value of each pixel after dead pixel filling and filtering, and the average photosensitive value of the second region may represent the average level of the photosensitive value acquired by the pixel in the second region, so that interference caused by inaccuracy of the photosensitive value acquired by the individual pixel is reduced, and improvement of the accuracy of the calculated T2 is facilitated. Meanwhile, the photosensitive value collected by the pixel at the edge in the Dark area can be eliminated when the Dark mean is calculated, so that the interference of external strong light is avoided, the photosensitive value collected by the pixel when the Dark is not sensed can be reflected more accurately, and the accuracy of the determined second exposure time length can be further improved. Both Target and Rawmean adopt Darkmean as subtraction, which is beneficial to eliminating the influence of the structure of the screen itself under the current environment on the photosensitive value acquired by the pixel, thereby further improving the adaptability of the T2 obtained by calculation to the current environment, leading the adaptability of the biological characteristic acquisition chip to the current environment to be better, reducing the influence of the change of the external environment on the acquisition performance, and being beneficial to further improving the accuracy of subsequent biological characteristic identification or registration.

In one embodiment, the configuration parameters mentioned in step 201 or step 701 include, in addition to the first exposure time, the first area and the target exposure value: acquiring a biometric image according to the second exposure duration mentioned in step 204 or step 707, where the upper limit duration corresponds to the photosensitive area and/or the lower limit duration corresponds to the photosensitive area, includes: under the condition that the configuration parameters further comprise an upper limit duration, if the second exposure duration is greater than the upper limit duration, acquiring a biological feature image according to the upper limit duration; and under the condition that the configuration parameters further comprise a lower limit time length, if the second exposure time length is less than the lower limit time length, acquiring the biological feature image according to the lower limit time length.

The upper limit time duration corresponding to the photosensitive area is denoted as T2_ max, and the lower limit time duration corresponding to the photosensitive area is denoted as T2_ min. The T2_ min and T2_ max may be set by those skilled in the art according to actual needs, so as to avoid too long or too short exposure time used when the biometric image is finally acquired, thereby ensuring that the finally acquired biometric image is relatively clear and convenient to identify or register. The inventor finds out through research that: the second exposure time calculated under abnormal conditions such as a strong light environment, an indoor environment, normal lighting of a light spot for picking up a picture and the like may be too small or too large. Therefore, by setting the upper limit duration and/or the lower limit duration, when the second exposure duration is longer than the upper limit duration, the biological characteristic image is acquired according to the upper limit duration; when the second exposure time is shorter than the lower limit time, the biological characteristic image is acquired according to the lower limit time, so that the condition that the finally acquired biological characteristic image is inaccurate due to the fact that the second exposure time calculated under the abnormal condition is possibly too small and too large is avoided, the finally acquired biological characteristic image is ensured to be relatively clear, and identification or registration is facilitated.

In one embodiment, the biometric acquisition chip is disposed in the terminal, the configuration parameters further include an upper limit duration corresponding to the photosensitive region and a lower limit duration corresponding to the photosensitive region, and the upper limit duration and the lower limit duration satisfy the following relationship:

T2_max＝T0+T0*a1

T2_min＝T0-T0*a2

wherein, T0 is the default exposure time length when the terminal leaves the factory, T2_ max is the upper limit time length, T2_ min is the lower limit time length, and a2 is greater than or equal to a 1. The values of a2 and a1 can be set according to actual needs, for example, the value ranges of a1 and a2 are as follows: a1 is more than or equal to 10 percent and less than or equal to 30 percent, and a2 is more than or equal to 30 percent and less than or equal to 50 percent. The default exposure duration when the terminal leaves the factory may be the default exposure duration set based on the result of the calibration of the whole machine when the terminal is in the stage of mass production of the whole machine. The inventor finds out through research that: the probability and the amplitude of the second exposure time length fluctuating towards the direction exceeding the default exposure time length are small, and the probability and the amplitude of the second exposure time length fluctuating towards the direction lower than the default exposure time length are large, so that the a2 is larger than or equal to the a1, and the method is favorable for adapting to different fluctuation conditions possibly existing in the second exposure time length actually.

For example, if the default exposure time at the time of terminal shipment is 50ms, T2_ max may be selected from 55ms (50+50 × 10% ═ 60ms) to 65ms (50+50 × 30% ═ 65 ms). T2_ min may be selected between 30ms (50-50 × 30% ═ 35ms) to (50-50 × 50% ═ 25 ms). If T2 is greater than 65ms, taking 65ms as the exposure time length, acquiring a biometric image, wherein T2_ max is 65ms, and T2_ min is 35 ms; if T2 is less than 35ms, then the biometric image is acquired with 35ms as the exposure duration.

In one embodiment, the configuration parameters mentioned in step 201 or step 701 further include: a Pulse Width Modulation (PWM) dimming period of the screen. Acquiring the biometric image according to the second exposure duration mentioned in step 204 or step 707 includes: and if the second exposure duration is not equal to the integral multiple of the PWM dimming period, adjusting the second exposure duration to be the integral multiple of the PWM dimming period, and acquiring the biological characteristic image according to the adjusted second exposure duration.

For example, the second exposure duration may be adjusted to be an integer multiple of the PWM dimming period by the following formula:

T2’＝(uint8(T2/T2_pwm))*T2_pwm

where T2' is the adjusted second exposure time duration, T2 is the second exposure time duration determined in step 203 or step 706, T2_ PWM is the PWM dimming period of the screen, and uint8 represents an unsigned integer data type.

In the present example, the inventors found through research that: for the high drop ratio type screen, when the second exposure duration is not equal to an integral multiple of the PWM dimming period, the acquired biometric image may have a horizontal stripe, for example, the fingerprint image shown in fig. 11 is the horizontal stripe image. Therefore, in this embodiment, the second exposure duration is adjusted to be an integer of the PWM dimming cycle, so that the adjusted second exposure duration is used to collect the biometric image, which is beneficial to avoiding the occurrence of cross striations in the biometric image collected by the biometric acquisition chip disposed below the screen with a high drop ratio, thereby improving the accuracy of the collected biometric image.

The brightness drop of the screen with the high drop ratio meets any one of the following conditions: when the PWM dimming mode is adopted for dimming, the brightness of the screen falls below 10% of the normal brightness of the screen between two PWM dimming periods; when the direct current dimming mode is adopted for dimming, the brightness of the screen between frames falls below 10% of the normal brightness of the screen. The normal brightness of the screen may be set according to actual needs, and the normal brightness of different screens may be different, which is not specifically limited in this embodiment. In a specific implementation, if the screen of the terminal belongs to a high drop ratio type screen, the PWM dimming period of the screen may be increased in the configuration parameters.

In one embodiment, an implementation of acquiring the biometric image according to the second exposure duration may refer to fig. 12, including:

step 1201: and adjusting the parameter value of the first parameter, the parameter value of the second parameter and the parameter value of the third parameter according to the second exposure duration to obtain the target parameter value of the first parameter, the target parameter value of the second parameter and the target parameter value of the third parameter.

Step 1202: and acquiring the biological characteristic image according to the target parameter value of the first parameter, the target parameter value of the second parameter and the target parameter value of the third parameter.

The first parameter is the duration of the line blanking period, denoted as H _ Blank. In the scanning process of converting the optical signal into the electric signal, the scanning always starts from the upper left corner of the image, the scanning advances horizontally, when the scanning point reaches the right edge of the image, the scanning point quickly returns to the left, the 2 nd line scanning is restarted under the starting point of the 1 st line, and the returning process between the lines is called horizontal blanking and also called line blanking.

The second parameter is the duration of the vertical blanking period, denoted as V _ Blank. A complete image scanning signal is formed by a sequence of line signals separated by horizontal blanking intervals, called a frame. After a frame is scanned by a scanning point, the scanning of a new frame is started from the lower right corner of the image to the upper left corner of the image, and this time interval is called vertical blanking and also called field blanking.

The third parameter is the Delay time for starting exposure for each line, and is denoted as V _ Delay. The third parameter is how long each row of pixels is delayed to begin exposure.

In step 1201, the biometric acquisition chip may determine a first scan duration required to scan a single row of pixels and a second scan duration required to scan a single pixel. Then, according to the first relation, adjusting the parameter value of the first parameter to obtain a target parameter value of the first parameter; and adjusting the parameter value of the second parameter and the parameter value of the third parameter according to the second relation to obtain a target parameter value of the second parameter and a target parameter value of the third parameter. The target parameter value of the first parameter conforms to a first relationship, and the first relationship is the relationship between the second scanning duration, the number of pixels in each row of the pixel array, and the parameter value of the first parameter and the first scanning duration. The target parameter value of the second parameter and the target parameter value of the third parameter conform to a second relationship, and the second relationship is a relationship between the first scanning duration, the total number of rows in the pixel array, the parameter value of the second parameter, the parameter value of the third parameter and the second exposure duration.

The First scanning time required for scanning a single line of pixels may be recorded as Row _ time, the size of Row _ time may be affected by the First Input First Output (FIFO) storage capability and the Serial Peripheral Interface (SPI) speed of the biometric acquisition chip, and the SPI speed may limit the minimum value of Row _ time. One biological characteristic acquisition chip has corresponding Row _ time, and the Row _ time can be obtained by testing the biological characteristic acquisition chip in a parameter test in a mass production stage and is stored in the biological characteristic acquisition chip.

The second scan duration required to scan a single pixel may be noted as 1/pixel _ clock, which is the clock period of the pixel. The pixel _ clock can be obtained by testing the biological characteristic acquisition chip in a parameter test in a mass production stage and stored in the biological characteristic acquisition chip. For example, pixel _ clock is 20MHz, and 1/pixel _ clock is 50 ns.

The number of pixels per row in the pixel array is denoted as H _ Valid, and the total number of rows in the pixel array is denoted as V _ Valid. It is understood that for a certain biometric acquisition chip, H _ Valid and V _ Valid in the biometric acquisition chip can be determined.

The first relationship may be expressed as follows:

Row_time＝(H_Blank+H_Valid)*(1/pixel_clock)

the second relationship may be expressed as follows:

it is understood that H _ Valid, V _ Valid, 1/pixel _ clock, Row _ time, and T2 in the first and second relationships are all determined values, and H _ Blank, V _ Blank, and V _ Delay are three parameter values to be adjusted.

In a specific implementation, H _ Blank may be adjusted according to the first relationship, so that a target parameter value of the first parameter that meets the first relationship is finally obtained, and finally, a parameter value that enables the first relationship to be established is used as the adjusted target parameter value of the first parameter.

In a specific implementation, V _ Blank and V _ Delay may be adjusted according to the second relationship, so as to finally obtain a target parameter value of the second parameter and a target parameter value of the third parameter that meet the second relationship, and finally, two parameter values that enable the second relationship to be established are used as the adjusted target parameter value of the second parameter and the adjusted target parameter value of the third parameter. Since the two parameters V _ Blank and V _ Delay exist in the second relationship as variables, one variable may be fixed first, and the other variable may be adjusted, and when the adjustment of the other variable fails to make the calculation result approach to T2, the adjustment of the previously fixed variable may be started, and by adjusting the two variables with each other, two target parameter values capable of establishing the second relationship may be finally obtained by adjustment.

In one embodiment, the configuration parameters further include: adjusting the lower limit parameter value of the first parameter according to the first relationship to obtain the target parameter value of the first parameter, including: and in the process of adjusting the parameter value of the first parameter according to the first relation, if the parameter value of the first parameter cannot meet the first relation when being adjusted to the lower limit parameter value, taking the lower limit parameter value as the target parameter value of the first parameter. The lower limit parameter value of the first parameter may be denoted as H _ Blank _ min, and H _ Blank _ min may be determined based on the minimum value of Row _ time, where the smaller the minimum value of Row _ time is, the smaller H _ Blank _ min is, the larger the minimum value of Row _ time is, and the larger H _ Blank _ min is. That is to say, in the present embodiment, in the process of adjusting H _ Blank, if H _ Blank is already equal to H _ Blank _ min and the first relationship cannot be established, H _ Blank _ min may be directly used as the target parameter value of the finally adjusted first parameter, that is, the target parameter value of the first parameter is H _ Blank _ min at the minimum. The parameter value of the first parameter directly affects the first scanning time Row _ time consumed by scanning a single Row of pixels, and Row _ time affects the normal output of the photosensitive value, so that the setting of the lower limit parameter value of the first parameter is beneficial to ensuring that the normal output of the photosensitive value is not affected while adjustment is carried out.

In an embodiment, in the process of adjusting the parameter values of H _ Blank, V _ Blank, and V _ Delay, the H _ Blank may also be directly adjusted to H _ Blank _ min in the configuration parameters, the V _ Delay is first fixed to 0, the V _ Blank is adjusted until the second relationship is not established by adjusting the V _ Blank, and then the V _ Delay is adjusted, so that the adjustment is beneficial to reducing the adjustment complexity and increasing the adjustment speed, thereby increasing the speed of acquiring the biometric image and the speed of performing biometric identification or registration subsequently.

After the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter are obtained after the adjustment, the target parameter values of the three parameters may be set in the biometric acquisition chip, so that the exposure duration finally presented when the biometric acquisition chip acquires the biometric image is T2.

In one embodiment, the biometric acquisition chip is an underscreen fingerprint acquisition chip, and the flowchart of the biometric acquisition method applied to the underscreen fingerprint acquisition chip can refer to fig. 13, which includes:

step 1301: and after the fingerprint light spot displayed on the screen is stable, the software terminal issues configuration parameters to the biological characteristic acquisition chip.

Wherein, the software end can be understood as after waiting for the fingerprint facula that shows on the screen to stabilize: after the software end determines that the fingerprint light spot displayed on the screen is pressed, the software end waits for a preset time length, wherein the preset time length is greater than or equal to the minimum time length required for the fingerprint light spot to be lightened until the fingerprint light spot is stable. And after the software end waits for the preset time length, the default fingerprint light spot is stable, and the software end issues configuration parameters to the biological characteristic acquisition chip.

The configuration parameters include: the exposure control method comprises the following steps of a first exposure time length T1, a first region, a Target photosensitive value Target, reference information, a filter coefficient, an upper limit time length T2_ max corresponding to the photosensitive region, a lower limit time length T2_ min corresponding to the photosensitive region and a lower limit parameter value H _ Blank _ min of the first parameter. The configuration parameters also include a PWM dimming period of the screen if the screen belongs to a high drop ratio screen.

Step 1302: and exposing the first area according to the first exposure duration to obtain a photosensitive value acquired by each pixel in the first area.

Step 1303: and removing the first type of pixels belonging to dead pixels in each pixel in the first area, taking the filling photosensitive value as the photosensitive value acquired by the first type of pixels, and filtering the photosensitive value acquired by the first type of pixels and the photosensitive value acquired by the second type of pixels in the first area according to the filter coefficient to obtain the filtered photosensitive value.

The filling photosensitive value is a first photosensitive value collected by a second type of pixel located around the first type of pixel.

Step 1304: and determining the average photosensitive value of the first area according to the filtered photosensitive value.

Step 1305: an average photo value for the second area is determined from photo values collected by pixels at non-edges of the second area.

Step 1306: and determining a second exposure time period T2 required by the photosensitive area to acquire the target photosensitive value according to the average photosensitive value of the first area, the average photosensitive value of the second area and the first exposure time period.

Step 1307: if T2 > T2_ max, then a biometric image is acquired according to T2_ max.

Step 1308: and if T2 is less than T2_ min, acquiring the biometric image according to T2_ min.

Step 1309: and if T2_ min is less than or equal to T2 is less than or equal to T2_ max, acquiring the biological characteristic image according to T2.

In step 1307, the underscreen fingerprint acquisition chip may adjust three parameters, H _ Blank, V _ Blank, and V _ Delay, according to T2_ max. The second relationship utilized in the adjustment may be expressed as follows:

in step 1308, the underscreen fingerprint acquisition chip may adjust three parameters, H _ Blank, V _ Blank, and V _ Delay, according to T2_ min. The second relationship utilized in the adjustment may be expressed as follows:

and finally, the under-screen fingerprint acquisition chip can acquire the biological characteristic image according to the three adjusted parameters. Wherein, the minimum of the H _ Blank can be adjusted to be H _ Blank _ min.

The biological characteristic acquisition method applied to the under-screen fingerprint acquisition chip in the embodiment can improve the adaptability of the under-screen fingerprint acquisition chip to fingerprint light spots, reduce the influence of fingerprint light spot fluctuation on fingerprint acquisition performance, and is favorable for improving the accuracy of fingerprint identification or registration.

The steps of the above methods are divided for clarity, and the implementation may be combined into one step or split some steps, and the steps are divided into multiple steps, so long as the same logical relationship is included, which are all within the protection scope of the present patent; it is within the scope of the patent to add insignificant modifications to the algorithms or processes or to introduce insignificant design changes to the core design without changing the algorithms or processes.

The embodiment of the present application further relates to a biometric acquisition chip, as shown in fig. 14, which includes a processing unit 1401 and a storage unit 1402 connected to the processing unit 1401, where the storage unit 1402 stores instructions executable by the processing unit 1401, and the instructions are executed by the processing unit 1401, so that the processing unit 1401 can execute the biometric acquisition method in any one of the above embodiments.

Embodiments of the present application are also directed to a terminal including a biometric acquisition chip as shown in fig. 14.

Embodiments of the present application also relate to a computer-readable storage medium storing a computer program. The computer program realizes the above-described method embodiments when executed by a processor.

That is, as can be understood by those skilled in the art, all or part of the steps in the method for implementing the embodiments described above may be implemented by a program instructing related hardware, where the program is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the method described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

Claims

1. A biological characteristic collection method is applied to a biological characteristic collection chip and comprises the following steps:

acquiring configuration parameters; wherein the configuration parameters include: the biological characteristic acquisition chip comprises a first exposure duration, a first area and a target photosensitive value, wherein the first area is a local area in a photosensitive area of the biological characteristic acquisition chip;

exposing the first area according to the first exposure duration, and acquiring a photosensitive value of the first area;

determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time;

and acquiring a biological characteristic image according to the second exposure duration.

2. The method according to claim 1, wherein the biometric acquisition chip is disposed in a terminal, and the acquiring the configuration parameters comprises:

and receiving the configuration parameters issued by the application software in the terminal.

3. The method according to claim 1, wherein the obtaining configuration parameters comprises:

when a preset trigger condition is detected, acquiring configuration parameters; wherein the preset trigger condition comprises: a biometric enrollment and/or a biometric identification is required.

4. The method according to claim 3, wherein the exposing the first region according to the first exposure duration and obtaining the exposure value of the first region comprises:

and when the preset trigger condition is detected, exposing the first area according to the first exposure time length after a preset time length is separated, and acquiring a photosensitive value of the first area.

5. The method according to claim 4, wherein the biometric acquisition chip is an underscreen fingerprint acquisition chip, and the biometric registration and/or biometric identification comprises: the area where the fingerprint light spot on the screen is detected to be pressed is longer than or equal to the minimum time length required for the fingerprint light spot to be stably lightened.

6. The biometric acquisition method according to any one of claims 1 to 5, wherein the configuration parameters further include: the method for determining reference information of a first type of pixel belonging to a dead pixel in the first area, and acquiring a sensitization value of the first area includes:

and acquiring the photosensitive value acquired by the second type of pixels except the first type of pixels in the first area according to the reference information.

7. The biometric acquisition method according to claim 6, wherein the reference information includes: label information for each pixel in the first region, the label information comprising: first marking information for representing that the pixel belongs to the dead pixel and second marking information for representing that the pixel does not belong to the dead pixel; alternatively, the first and second electrodes may be,

the reference information includes: and determining the coordinate information of the bad block area based on the first type pixels belonging to the bad point.

8. The biometric acquisition method of claim 6, wherein the configuration parameters further comprise: a filter coefficient; after the acquiring, according to the reference information, the light-sensitive values acquired by the second type of pixels in the first region except the first type of pixels, the method further includes:

taking the filling photosensitive value as the photosensitive value collected by the first type of pixels; wherein, the filling photosensitive value is the photosensitive value collected by the second type of pixels around the first type of pixels;

filtering the photosensitive value acquired by the first type of pixels and the photosensitive value acquired by the second type of pixels according to the filter coefficient to obtain filtered photosensitive values;

determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the photosensitive value of the first area and the first exposure time, including:

and determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value and the first exposure time.

9. The method of claim 8, wherein determining a second exposure time period required to acquire the target photosensitive value in the photosensitive area according to the filtered photosensitive value and the first exposure time period comprises:

acquiring a photosensitive value of the second area; the second area is an edge area of the photosensitive area, the second area is not overlapped with the first area, and the edge area is an area for detecting circuit noise of the biological characteristic acquisition chip;

and determining a second exposure time required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value, the photosensitive value of the second area and the first exposure time.

10. The method according to claim 9, wherein the obtaining the exposure value of the second region comprises:

and acquiring the photosensitive value acquired by the pixel at the non-edge of the second area.

11. The method according to claim 9, wherein the obtaining the exposure value of the second region comprises:

and acquiring a photosensitive value acquired by a middle a column pixel and/or a middle a row pixel of the second area, wherein a is an integer greater than or equal to 1.

12. The method according to any one of claims 9 to 11, wherein said determining a second exposure time period required for acquiring the target photosensitive value in the photosensitive area according to the filtered photosensitive value, the photosensitive value of the second area and the first exposure time period comprises:

determining an average photosensitive value of the first area according to the filtered photosensitive value;

determining an average photosensitive value of the second area according to the photosensitive value acquired by the pixels in the second area;

and determining a second exposure time length required for acquiring the target photosensitive value in the photosensitive area according to the average photosensitive value of the first area, the average photosensitive value of the second area and the first exposure time length.

13. The method according to claim 12, wherein determining a second exposure time period required for acquiring the target photosensitive value in the photosensitive area according to the average photosensitive value of the first area, the average photosensitive value of the second area, and the first exposure time period comprises:

calculating the second exposure time period by the following formula:

wherein T2 is the second exposure time period, T1 is the first exposure time period, Target is the Target photosensitive value, Rawmean is the average photosensitive value of the first region, and Darkmean is the average photosensitive value of the second region.

14. The biometric acquisition method according to claim 8, wherein the biometric acquisition chip is disposed below a screen, and the filter coefficient is determined according to a structure of the screen; the screen is in a soft screen or hard screen structure, and the filter coefficient determined based on the hard screen is larger than the filter coefficient determined based on the soft screen.

15. The biometric acquisition method according to any one of claims 1 to 5, wherein the configuration parameters further include: acquiring a biological feature image according to the second exposure time, wherein the upper limit time corresponding to the photosensitive area and/or the lower limit time corresponding to the photosensitive area comprises:

under the condition that the configuration parameters further comprise the upper limit duration, if the second exposure duration is longer than the upper limit duration, acquiring a biological feature image according to the upper limit duration;

and under the condition that the configuration parameters further comprise the lower limit duration, if the second exposure duration is less than the lower limit duration, acquiring a biological feature image according to the lower limit duration.

16. The method according to claim 15, wherein the biometric acquisition chip is disposed in a terminal, the configuration parameters further include an upper limit duration corresponding to the photosensitive region and a lower limit duration corresponding to the photosensitive region, and the upper limit duration and the lower limit duration satisfy the following relationship:

T2_max＝T0+T0*a1

T2_min＝T0-T0*a2

the T0 is a default exposure duration of the terminal when leaving a factory, the T2_ max is the upper limit duration, the T2_ min is the lower limit duration, and the a2 is greater than or equal to the a 1.

17. The method for collecting the biological characteristics of the claim 16, wherein the value ranges of the a1 and the a2 are as follows:

10％≤a1≤30％，30％≤a2≤50％。

18. the biometric acquisition method according to any one of claims 1 to 5, wherein the biometric acquisition chip is disposed below a screen, and the configuration parameters further comprise: a PWM dimming period of the screen;

and acquiring a biological characteristic image according to the second exposure duration, wherein the acquisition comprises the following steps:

if the second exposure duration is not equal to the integral multiple of the PWM dimming period, adjusting the second exposure duration to be the integral multiple of the PWM dimming period;

and acquiring a biological characteristic image according to the adjusted second exposure duration.

19. The biometric acquisition method according to any one of claims 1 to 5, wherein the first exposure time period is determined according to a linearity of the biometric acquisition chip, and the smaller the linearity, the smaller the first exposure time period is determined.

20. The biometric acquisition method according to any one of claims 1 to 5, wherein the first exposure time period is greater than 0 msec and less than or equal to 10 msec.

21. The method according to any one of claims 1 to 5, wherein the biometric acquisition chip is disposed below a screen, the target exposure value is determined based on a gain value corresponding to a structure of the screen, the structure of the screen is a soft screen or a hard screen, and the gain value corresponding to the soft screen is greater than the gain value corresponding to the hard screen.

22. The method according to any one of claims 1 to 5, wherein the biometric acquisition chip is disposed below a screen, the area of the first region is determined according to the structure of the screen, the structure of the screen is a soft screen or a hard screen, and the area of the first region determined based on the soft screen is larger than the area of the first region determined based on the hard screen.

23. The method according to any one of claims 1 to 5, wherein the center of the first region is a light-condensing center of the light-sensing region.

24. The method according to any one of claims 1 to 5, wherein the number of pixels in the first region is an integral multiple of the number of pixels to be read out in a one-pixel mode determined based on image readout mode binning of the biometric acquisition chip.

25. The method according to any one of claims 1 to 5, wherein the biometric acquisition chip comprises a pixel array having a plurality of pixels, and the acquiring the biometric image according to the second exposure duration comprises:

adjusting the parameter value of the first parameter, the parameter value of the second parameter and the parameter value of the third parameter according to the second exposure duration to obtain a target parameter value of the first parameter, a target parameter value of the second parameter and a target parameter value of the third parameter; the first parameter is the time length of a line blanking period, the second parameter is the time length of a field blanking period, and the third parameter is the delay time length for starting exposure of each line of pixels;

and acquiring a biological characteristic image according to the target parameter value of the first parameter, the target parameter value of the second parameter and the target parameter value of the third parameter.

26. The method of claim 25, wherein the adjusting the parameter value of the first parameter, the parameter value of the second parameter, and the parameter value of the third parameter according to the second exposure duration to obtain the target parameter value of the first parameter, the target parameter value of the second parameter, and the target parameter value of the third parameter comprises:

determining a first scanning time period required for scanning a single row of pixels and a second scanning time period required for scanning a single pixel;

adjusting the parameter value of the first parameter according to the first relation to obtain a target parameter value of the first parameter; wherein the target parameter value of the first parameter conforms to the first relationship, and the first relationship is:

Row_time＝(H_Blank+H_Valid)*(1/pixel_clock)

wherein Row _ time is the first scanning duration, 1/pixel _ clock is the second scanning duration, H _ Blank is a parameter value of the first parameter, and H _ Valid is the number of pixels in each Row of the pixel array;

according to the second relation, adjusting the parameter value of the second parameter and the parameter value of the third parameter to obtain a target parameter value of the second parameter and a target parameter value of the third parameter; wherein the target parameter value of the second parameter and the target parameter value of the third parameter conform to the second relationship, and the second relationship is:

wherein T2 is the second exposure duration, V _ Blank is a parameter value of the second parameter, V _ Valid is a total number of rows in the pixel array, and V _ Delay is a parameter value of the third parameter.

27. The biometric acquisition method of claim 26, wherein the configuration parameters further comprise: the adjusting the lower limit parameter value of the first parameter according to the first relationship to obtain the target parameter value of the first parameter includes:

in the process of adjusting the parameter value of the first parameter according to the first relationship, if the parameter value of the first parameter cannot meet the first relationship when being adjusted to the lower limit parameter value, the lower limit parameter value is used as the target parameter value of the first parameter.

28. A biometric acquisition chip comprising a processing unit and a memory unit coupled to the processing unit, the memory unit storing instructions executable by the processing unit, the instructions being executable by the processing unit to enable the processing unit to perform the biometric acquisition method as recited in any one of claims 1 to 27.

29. A terminal comprising the biometric acquisition chip of claim 28.

30. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the biometric acquisition method of any one of claims 1 to 27.