CN111896971A - TOF sensing device and distance detection method thereof - Google Patents
TOF sensing device and distance detection method thereof Download PDFInfo
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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Abstract
The application discloses TOF sensing device and distance detection method thereof, including: emitting pulse detection light to irradiate a detected visual field, wherein the pulse detection light at least comprises pulses with two different pulse widths; receiving the reflected pulse detection light, and obtaining initial distance information at each position in the measured field of view according to the time interval from emission to reception of the pulse detection light; and combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information of each position in the measured field of view. The TOF sensing device and the ranging method thereof can reduce the influence of multipath reflected light and improve the accuracy of distance detection.
Description
Technical Field
The application relates to the technical field of sensing, in particular to a TOF sensing device and a distance detection method thereof.
Background
A Time of Flight (ToF) sensor measures the distance, three-dimensional structure, or three-dimensional profile of an object to be measured by detecting the Time interval between transmission and reception of an emitted pulse signal or the phase generated by a laser light traveling back and forth once to the object. The TOF sensor can simultaneously obtain a gray image and a distance image, and is widely applied to the fields of somatosensory control, behavior analysis, monitoring, automatic driving, artificial intelligence, machine vision, automatic 3D modeling and the like.
In the actual distance detection process, due to the complex environment in the detected field of view, a plurality of reflecting surfaces are usually present, which causes the multipath reflection problem, including: the detection light may reach the surface of the object to be measured after being reflected for many times after being emitted, and the reflected light reflected by the object to be measured may be received by the time-of-flight sensor after being reflected for many times. The multipath reflection problem can cause the flying distance of the detection light from the emitting to the receiving after being reflected to be more than 2 times of the actual distance of the object to be detected, thereby affecting the accuracy of distance detection.
In the prior art, for the problem of Multi-path interference (MPI), a complicated algorithm is usually used to correct the problem so as to reduce the influence of the Multi-path reflected light on the detection result, which has a high requirement on the computing capability of the sensor, resulting in an increase in cost.
Disclosure of Invention
In view of this, the present application provides a TOF sensing apparatus and a distance detecting method thereof to correct the influence of multipath reflected light on a detection structure and improve the accuracy of distance detection.
The application provides a distance detection method of a TOF sensing device, which comprises the following steps: emitting pulse detection light to irradiate a detected visual field, wherein the pulse detection light at least comprises pulses with two different pulse widths; receiving the reflected pulse detection light, and obtaining initial distance information at each position in the measured field of view according to the time interval from emission to reception of the pulse detection light; and combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information of each position in the measured field of view.
Optionally, in the measurement process, each detection frame adopted includes a plurality of detection subframes, and each detection subframe corresponds to a pulse with one pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain a frame of measurement distance information.
Optionally, the TOF sensing device generates induced charges corresponding to energy of reflected light after receiving the reflected light; the distance detection method comprises the following steps: and accumulating the induced charges by using three continuous charge accumulation windows, wherein the window width of each charge accumulation window is consistent with the pulse width of the detection light of the current detection frame.
Optionally, the field to be measured includes multiple measuring ranges, and multiple pulses with different pulse widths corresponding to the measuring ranges are set according to the detection precision requirement in each measuring range, and the smaller the pulse width is, the shorter the measuring range is, and the smaller the influence of multipath reflected light on the detection result is.
Optionally, the pulse width setting method of the pulse detection light includes: performing distance detection by detecting light with an initial pulse having a basic pulse whose pulse width corresponds to a maximum measurement range; when a target object appears in the measured field of view, the initial pulse detection light is adjusted to be modified pulse detection light, the modified pulse detection light includes the basic pulse and a modified pulse, and the pulse width of the modified pulse is smaller than that of the basic pulse.
Optionally, before the target object appears, each detection frame adopts a basic pulse to perform distance detection; after the target object appears, each detection frame comprises at least two detection sub-frames, and the basic pulse and the correction pulse are respectively adopted for distance detection.
Further comprising: and adjusting the starting point of the range corresponding to the correction pulse by controlling the light-emitting time sequence of the correction pulse, so that the range of the detection subframe corresponding to the correction pulse covers the distance range of the target object.
Optionally, the target object is selected according to a detection result of the detection light of the initial pulse.
Alternatively, an object appearing within a preset distance range is automatically set as the target object.
The technical scheme of the invention also provides a TOF sensing device, which comprises: a light source module for emitting pulsed detection light; the sensing module is used for receiving reflected light of the pulse detection light reflected by the object to be detected; the processor is connected with the light source module and the sensing module and is used for controlling the light source module and the sensing module; a memory storing a computer application program operable on the processor; wherein the computer program when executed by the processor implements any of the distance detection methods described above.
The ranging method of the TOF sensing device has the advantages that the distance detection is carried out through the pulse detection light with different pulse widths, a large detection range is obtained through the wide pulse, meanwhile, the influence of multipath reflected light can be reduced through the narrow pulse, the measurement accuracy in a certain range is improved, a complex algorithm is not needed, the implementation mode is simple, and the cost is low.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic flow chart of a method for measuring distance of a TOF sensing apparatus according to an embodiment of the present disclosure;
FIG. 2a is a schematic diagram of pulse detection light according to an embodiment of the present invention;
FIG. 2b is a schematic diagram of pulse detection light according to an embodiment of the present invention;
FIG. 3a is a timing diagram of the charge accumulation window and the pulse detection light and reflected light according to an embodiment of the present invention;
FIG. 3b is a timing diagram of the charge accumulation window and the pulse detection light and reflected light according to an embodiment of the present invention;
FIG. 3c is a timing diagram of the charge accumulation window and the pulse detection light and reflected light according to an embodiment of the present invention;
FIG. 3d is a timing diagram of the charge accumulation window and the pulse detection light and reflected light according to an embodiment of the present invention;
FIG. 4 is a timing diagram of pulse detection light used in an embodiment of the present invention;
FIG. 5 is a flowchart illustrating a pulse width setting method for pulse detection light according to an embodiment of the invention;
FIG. 6 is a schematic diagram of pulse detection light used in an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a TOF sensing apparatus according to an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The following embodiments and their technical features may be combined with each other without conflict.
Fig. 1 is a schematic flow chart of a distance measuring method of a TOF sensing device according to an embodiment of the invention.
The distance measuring method comprises the following steps:
step S101: the field of view to be measured is illuminated by emitting pulsed detection light comprising at least two pulses of different pulse widths.
The TOF sensing device includes a light source module for emitting detection light into a field of view to be measured. The pulse detection light is modulated pulse light, which may be light that is easy to modulate, such as LED light or laser light, and irradiates all objects within the field of view of the subject. The pulse detection light reaches the surface of the object to be measured, and is reflected on the surface of the object to be measured to form reflected light; and simultaneously, the environment light exists in the environment where the object to be measured is located. In an actual usage scenario, the optical signal received by the time-of-flight sensing device through the sensing module includes both the pulse reflected light and the ambient light. In the following description of the embodiments, the reflected light received by the sensor array includes both the pulse reflected light and the ambient light.
The TOF sensing device further comprises a sensing module, wherein the sensing array comprises a plurality of pixel units, namely optical sensing units, and can convert optical signals into electric signals, so that received reflected light can be converted into a certain amount of induced charges corresponding to the energy of the reflected light through the sensing module, and a detection value corresponding to the energy of the reflected light is accumulated and output through a charge accumulation window.
In this embodiment, the pulse detection light includes pulses of at least two different pulse widths. Different pulse widths correspond to different range ranges, and the larger the pulse width is, the larger the range is. Under the condition that the pulse width is T, the range is 0-cT/2. The start of the range can be adjusted by adjusting the timing of the pulse relative to the charge accumulation window, for example, the pulse with the same pulse width T, and the corresponding range can also be d-cT/2 + d, where d is determined by the time of pulse width shift, as will be analyzed in the following embodiments.
Fig. 2a is a schematic diagram of pulse detection light according to an embodiment of the invention.
In this embodiment, the pulse detection light includes two different pulse widths, namely a first pulse P1 and a second pulse P2, and the pulse width of the second pulse P2 is smaller than that of the first pulse P1. The detection frame interval corresponding to the first pulse P1 and the second pulse P2 is set as in detection subframe 1 and detection subframe 2, each of which corresponds to a plurality of pulses of the same pulse width.
Fig. 2b is a schematic diagram of pulse detection light according to another embodiment of the present invention.
In this embodiment, the pulse detection light periodically uses the first pulse P1 and the second pulse P2, and after the plurality of first pulses P1 are transmitted to complete a plurality of detection frames corresponding to the first pulses P1, the plurality of second pulses P2 are transmitted to perform a plurality of detection frames corresponding to the second pulses P2.
In other embodiments, the pulse detection light may further include three or more pulses with different pulse widths, and the pulse timings with different pulse widths are reasonably set according to actual requirements.
Step S102: the reflected detection light is received, and initial distance information at each position in the measured field of view is obtained according to the time interval from the emission to the reception of the pulse detection light.
The pulse detection light is reflected and then received by the sensing module. According to the distance of the object to be measured, the time for receiving the reflected light is different, and the initial distance information of each position can be calculated according to the time interval from the emission of the pulse detection light to the receiving of the reflected pulse.
Specifically, after receiving reflected light, a sensing module of the TOF sensing device generates induced charges corresponding to the energy of the reflected light; in this embodiment, the induced charges are accumulated by using three consecutive charge accumulation windows, and the window width of each charge accumulation window is consistent with the pulse width of the detection light of the current detection frame.
Referring to FIG. 3a, a timing diagram of the charge accumulation window and the pulse detection light and the reflected light in a detection frame is shown.
The detection frame shown in FIG. 3a corresponds to the first pulse P1 of the pulse detection light LO1, the first pulse P1 having a pulse width T1。
The first charge accumulation window G11, the second charge accumulation window G12, and the third charge accumulation window G13 correspond to a capacitive shutter structure, respectively, and the capacitive shutter structure accumulates induced charges through capacitance and controls the opening and closing of each charge accumulation window through a control signal having a certain timing sequence. The window widths of the first, second and third charge accumulation windows G11, G12, G13 are consistent with the pulse width of the first pulse width P1, all T1。
Wherein G11, G12, and G13 are turned on in sequence, and since ambient light is always present during the distance detection, the first charge accumulation window G1 is used to accumulate induced charges generated by the ambient light. In this embodiment, the opening edge of the second charge accumulation window G12 is aligned with the generation edge of the first pulse P1, and the second charge accumulation window G12 and the third charge accumulation window G13 are used to accumulate induced charges generated by the reflected light of the ambient light and the pulse detection light.
The amounts of the induced charges accumulated by G11, G12, and G13 are Q11, Q12, and Q13, respectively. The initial detection distance can be obtained by calculation according to the quantity of the induced charges
The range of the first pulse P1 capable of detecting is 0-cT1/2。
During the detection process, the second charge accumulation window G12 and the third charge accumulation window G13 can simultaneously accumulate the induced charges generated by the multipath reflected light MPI, and the multipath reflected light MPI has a large optical path due to multiple reflections, is received behind the effective reflected light LB1, and is accumulated by the second charge accumulation window G12 and the third charge accumulation window G13, which results in a large detection result. During the charge accumulation process, the second charge accumulation window G12 and the third charge accumulation window G13 cannot distinguish the induced charges generated by the normal reflected light from the multipath reflected light, and therefore, the influence of the multipath reflected light on the detection result cannot be eliminated.
Referring to fig. 3b, a charge accumulation window corresponding to the second pulse P2 of pulse detection light and a timing diagram of the pulse detection light and the reflected light are shown.
The second pulse P2 has a pulse width T2In the detection frame, the window widths of the first charge accumulation window G21, the second charge accumulation window G22 and the third charge accumulation window G23 are consistent with the pulse width of the second pulse width P2, and all T2。
Under the detection frame, the interference of multipath reflected light MPI also exists. Under the same detection scene, the intensity and energy of the multipath reflected light MPI in the detection frame shown in fig. 3a and 3b are substantially consistent. However, since FIG. 3b detects the pulse width T of the second pulse P2 under the frame2Less than the pulse width T of the first pulse P11I.e. T2<T1(ii) a The window widths of the respective charge accumulation windows G22 and G23 are also smaller than those of G12 and G13, respectively, and therefore, the charge accumulation time is shortened, and therefore, the charges generated by part of the multi-path reflected light MPI cannot be accumulated, so that the influence of the multi-path reflected light on the detection result can be reduced, relative to the detection result having a larger pulse width T1The accuracy of distance detection can be improved by using the second pulse P2 as the first pulse P1.
In this embodiment, the rising edge of the second pulse P2 is aligned with the opening edge of the second charge accumulation window G22, so the range of the second pulse P2 can be detected is 0 to cT2/2. Thus in the range of 0 to cT2In the range of/2, the accuracy of the initial distance information obtained using the second pulse P2 is greater than the accuracy of the initial distance information obtained using the first pulse P1.
In other embodiments, the start of the range corresponding to the second pulse P2 can be shifted by adjusting the timing of the second pulse P2 relative to the second charge accumulation window G22.
Referring to fig. 3c, the pulse detect light second pulse P2 is delayed by a time t relative to the second charge accumulation window G22. In this case, the detectable range is
Referring to fig. 3d, the pulse detect light second pulse P2 is shifted forward by a time t relative to the second charge accumulation window G22. In this case, the detectable range is
By controlling the timing of the second pulse P2, the range of the detectable range of the second pulse P2 can be adjusted to cover 0-cT1Any distance range within/2.
And S103, combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information of each position in the measured field of view.
Specifically, the initial distance information at each position obtained from the second pulse P2 is substituted for the initial distance information at the corresponding position obtained from the first pulse P1 to form actual measured distance information at each position within the entire measured field of view.
Specifically, a plurality of detection frames are adopted for distance detection, each detection frame comprises a plurality of detection subframes, and each detection subframe corresponds to a pulse with one pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain a frame of measurement distance information.
In this embodiment, the pulse detection light includes a first pulse P1 corresponding to the detection sub-frame 1 and a second pulse P2 corresponding to the detection sub-frame 2, please refer to fig. 2a, the detection sub-frame 1 and the detection sub-frame 2 are arranged at intervals, the distance information obtained by the detection sub-frame 1 and the detection sub-frame 2 is combined to obtain the information of the measured distance number of one frame, and finally, the 2n frames of data are combined to obtain n frames of data.
Taking fig. 3b as an example, in the data merging process, for each pixel unit, the range of 0 to cT can be used2In the measuring range of/2, searching initial distance information acquired by the detection subframe 2; when the range is exceeded and the initial distance information corresponding to the detection subframe 1 is searched, the initial distance information in the detection frame of the detection subframe 1 is combined with the searched data of the detection subframe 1 and the detection subframe 2, and finally the measurement distance information corresponding to all pixel units is obtained, so that 0-cT in the whole measured field is obtained1A depth image in the range of/2. Within the depth image, 0 to cT2The measurement depth information in the/2 range has higher accuracy and is less influenced by MPI.
In the embodiment, the distance detection is performed by detecting the light through the pulses with different pulse widths, a larger detection range is obtained through the wide pulses, and meanwhile, the influence of multipath reflected light can be reduced through the narrow pulses, so that the measurement accuracy in a certain range is improved, a complex algorithm is not needed, the implementation mode is simple, and the cost is low.
In other embodiments, the pulse width of each pulse in the pulse detection light corresponding to each range may also be set according to the detection accuracy requirement in different ranges within the measured field of view, and the smaller the pulse width, the smaller the corresponding range, and the higher the detection accuracy.
For example, in one embodiment, the measured field of view may be divided into three ranges of measurement ranges, including 0 d1, d1 d2, d2 d3, with closer regions requiring higher measurement accuracy.
Please refer to fig. 4, which is a timing diagram of the pulse detection light used in the embodiment. In this embodiment, according to the detection accuracy of different measuring range, the pulse detection light includes three kinds of pulses with different pulse widths, which are sequentially set as a first pulse P41, a second pulse P42, and a third pulse P43. The pulse width of the first pulse P41 is maximum, and the maximum range is 0-d 3; the pulse width of the second pulse P42 is smaller than that of the first pulse P41 and corresponds to a second measuring range d 1-d 2; the pulse width of the third pulse P43 is smaller than that of the second pulse P42, and corresponds to the third range of measurement ranges 0-d 1.
After the initial distance information data of three subframes are obtained through the first pulse P41, the second pulse P42 and the third pulse P43, the three subframe data are combined to obtain one frame of measured distance information. Specifically, in the range of the range from 0 to d1, the initial distance information of the detection subframe corresponding to the third pulse P43 is adopted; in the range of the range d 1-d 2, adopting the initial distance information in the detection frame corresponding to the second pulse P42; in the range of the range d 2-d 3, adopting the initial distance information of the detection frame corresponding to the first pulse P41; finally, the measured distance information at each position in the range of 0-d 3 in the measured field of view is obtained, and the measured distance information in the three ranges of 0-d 1, d 1-d 2 and d 2-d 3 respectively correspond to different detection accuracies.
By adopting the distance measuring method, higher detection precision can be obtained in a short-distance range, and ground navigation equipment, such as a sweeping robot, a navigation robot and other equipment with higher requirements on the short-distance detection precision, can be facilitated.
In another embodiment, the pulse width of the pulse detection light may be dynamically adjusted.
Fig. 5 is a schematic flow chart illustrating a pulse width setting method for pulse detection light according to an embodiment of the present invention.
In this embodiment, the pulse width setting method of pulse detection light includes the following steps:
and step S501, detecting the distance by using initial pulse detection light with basic pulses, wherein the pulse width of the basic pulses corresponds to the maximum measuring range.
In the initial stage of detection, the initial pulse detection light LO1 (please refer to fig. 6) has only a basic pulse P61 with a single pulse width, corresponding to the maximum range in the field of view to be detected. Distance information at each position within the whole range of the measured field of view can be obtained through the basic pulse P61.
And S502, when a target object appears in the detected field of view, adjusting the initial pulse detection light into correction pulse detection light, wherein the correction pulse detection light comprises the basic pulse and a correction pulse, and the pulse width of the correction pulse is smaller than that of the basic pulse.
The user may select the target object based on the depth image obtained from the initial detection light LO1, for example, by presenting the depth image to the user through a display screen, and selecting the person as the target object when the user finds that an object of interest, such as a portrait, appears in the selected field of view, and the selection of the target object may be achieved by touching or other manipulation.
In other embodiments, an object appearing within a preset distance range may be automatically set as the target object. For example, when the TOF sensing apparatus is used for real-time monitoring, a sensitive area may be set, and when any object appears in the sensitive area, the object is regarded as a target object.
After the target object appears, the initial detection light LO1 is adjusted according to the distance range of the target object to form the corrected detection light LO2, so as to improve the detection accuracy of the target object. Specifically, after the distance range of the target object is obtained through the initial detection light LO1, a correction pulse P62 is formed, and the pulse width and the time sequence of the correction pulse P62 correspond to the range covering the distance range of the target object. For example, the distance range at each position of the target object is a 1-a 2, the pulse width and the timing of the correction pulse P62 correspond to the ranges a1 'to a 2', a2 'is equal to or slightly larger than a2, and a 1' is equal to or slightly smaller than a 1.
Before the target object appears, each detection frame adopts the basic pulse P61 to carry out distance detection; after the target object appears, each detection frame comprises at least two detection subframes, and the distance detection is carried out by respectively adopting the basic pulse P61 and the correction pulse P62.
The correction pulse P62 and the detection subframe corresponding to the basic pulse P61 are arranged at intervals, each detection frame respectively comprises a sub-detection frame corresponding to the correction pulse P62 and a sub-detection frame corresponding to the basic pulse P61, and the initial distance information of the two sub-detection frames is combined to obtain one frame of measurement distance information. Referring to fig. 6, the initial distance information of the detection subframe 11 and the detection subframe 12 are combined to form the measurement distance information of the detection frame 1; the initial distance information of the detection sub-frame 21 and the detection sub-frame 22 are combined to form the measurement distance information of the detection frame 2. The finally obtained measurement distance information has higher detection precision for the area where the target object is located. Each detection sub-frame in fig. 6 is only illustrated by one pulse, and in the actual measurement process, multiple repeated light pulses of the same kind are corresponding to one detection sub-frame, and are repeated for hundreds of thousands or even tens of thousands of times, so that enough charge is accumulated to improve the detection accuracy.
In the case where the distance range to the target object is relatively large, the measurement range of the sub-detection corresponding to the correction pulse P62 can be made to cover the distance range to the target object by shifting forward or backward the partial sub-detection frame correction pulse P62.
The embodiment of the invention also provides a TOF sensing device.
Please refer to fig. 7, which is a schematic structural diagram of the TOF sensing apparatus.
The TOF sensing apparatus includes: a light source module 701, a sensing module 702, and a processor 703 and memory 704.
The light source module 701 is used for emitting pulse detection light. The light source module 701 may be an infrared light source, and the processor 703 may send a control signal to the light source module 701 to adjust parameters such as the light emitting intensity, the pulse width, and the period of the light source module 701.
The sensing module 702 is configured to receive the reflected light of the pulse detection light reflected by the object to be measured. The sensing module 702 includes an array of pixel cells capable of receiving light signals and converting the light signals into electrical signals to generate induced charges corresponding to the received light. The processor 703 is connected to the sensing module 702, and is configured to acquire a sensing signal of the sensing module 702.
The memory 704 may be a non-volatile memory and may store a computer application program capable of running on the processor 703, wherein the computer program, when executed by the processor 703, implements the distance detection method described in any of the above embodiments.
In some embodiments, during the distance detection process, the processor 703 can control the light source module 701 to emit pulse detection light to irradiate the field of view to be detected, where the pulse detection light includes at least two pulses with different pulse widths; the reflected pulse detection light is received by the sensing module 702, and the processor 703 may invoke a computer application program in the memory 704 to obtain initial distance information at each location in the field of view of the subject based on the time interval between the emission and the reception of the pulse detection light, and combine the initial distance information obtained from the pulses of different pulse widths to obtain measured distance information at each location in the field of view of the subject.
That is, the above description is only an embodiment of the present application, and not intended to limit the scope of the present application, and all equivalent structures or equivalent flow transformations made by using the contents of the specification and the drawings, such as mutual combination of technical features between various embodiments, or direct or indirect application to other related technical fields, are included in the scope of the present application.
Claims (10)
1. A distance detection method of a TOF sensing apparatus, comprising:
emitting pulse detection light to irradiate a detected visual field, wherein the pulse detection light at least comprises pulses with two different pulse widths;
receiving the reflected pulse detection light, and obtaining initial distance information at each position in the measured field of view according to the time interval from emission to reception of the pulse detection light;
and combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information of each position in the measured field of view.
2. The distance detection method according to claim 1, wherein each detection frame used in the measurement process comprises a plurality of detection subframes, each detection subframe corresponding to a pulse with a pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain a frame of measurement distance information.
3. The distance detection method of claim 1, wherein said TOF sensing device generates an induced charge corresponding to the energy of the reflected light upon receipt of the reflected light; the distance detection method comprises the following steps: and accumulating the induced charges by using three continuous charge accumulation windows, wherein the window width of each charge accumulation window is consistent with the current pulse width of the detected light.
4. The distance detection method according to claim 1, wherein the field of view to be measured includes a plurality of measurement range ranges, and a plurality of kinds of pulses having different pulse widths are set in accordance with a detection accuracy requirement for each measurement range, and the measurement range corresponding to the smaller pulse width is shorter and the detection result is less affected by multipath reflected light.
5. The distance detection method according to claim 1, wherein the pulse width setting method of pulse detection light comprises: performing distance detection by detecting light with an initial pulse having a basic pulse whose pulse width corresponds to a maximum measurement range; when a target object appears in the measured field of view, the initial pulse detection light is adjusted to be modified pulse detection light, the modified pulse detection light includes the basic pulse and a modified pulse, and the pulse width of the modified pulse is smaller than that of the basic pulse.
6. The distance detection method according to claim 5, wherein, before the occurrence of the target object, each detection frame is subjected to distance detection using a basic pulse; after the target object appears, each detection frame comprises at least two detection sub-frames, and the basic pulse and the correction pulse are respectively adopted for distance detection.
7. The distance detection method according to claim 6, further comprising: and adjusting the starting point of the range corresponding to the correction pulse by controlling the light-emitting time sequence of the correction pulse, so that the range of the detection subframe corresponding to the correction pulse covers the distance range of the target object.
8. The distance detection method according to claim 7, wherein the target object is selected based on a detection result of the detection light of the initial pulse.
9. The distance detection method according to claim 7, characterized in that an object appearing within a preset distance range is automatically set as a target object.
10. A TOF sensing apparatus, comprising:
a light source module for emitting pulsed detection light;
the sensing module is used for receiving reflected light of the pulse detection light reflected by the object to be detected;
the processor is connected with the light source module and the sensing module and is used for controlling the light source module and the sensing module;
a memory storing a computer application program operable on the processor;
wherein the computer program, when executed by the processor, implements the distance detection method of any of claims 1 to 9.
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