WO2022012341A1 - 投影设备、投影设备的自动对焦方法以及装置 - Google Patents

投影设备、投影设备的自动对焦方法以及装置 Download PDF

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Publication number
WO2022012341A1
WO2022012341A1 PCT/CN2021/103973 CN2021103973W WO2022012341A1 WO 2022012341 A1 WO2022012341 A1 WO 2022012341A1 CN 2021103973 W CN2021103973 W CN 2021103973W WO 2022012341 A1 WO2022012341 A1 WO 2022012341A1
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Prior art keywords
projection
module
move
sharpness
projection device
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PCT/CN2021/103973
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English (en)
French (fr)
Inventor
邓岳慈
李屹
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深圳光峰科技股份有限公司
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Publication of WO2022012341A1 publication Critical patent/WO2022012341A1/zh

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/53—Means for automatic focusing, e.g. to compensate thermal effects
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/282—Autofocusing of zoom lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
    • G02B7/38—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals measured at different points on the optical axis, e.g. focussing on two or more planes and comparing image data
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B30/00—Camera modules comprising integrated lens units and imaging units, specially adapted for being embedded in other devices, e.g. mobile phones or vehicles
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/317—Convergence or focusing systems

Definitions

  • the present application relates to the field of projection technology, and in particular, to a projection device, an automatic focusing method and device for the projection device.
  • the projection device is generally used to project the interface image displayed on the related device connected to it, such as projecting the interface image displayed on the screen of the computer and the mobile phone device.
  • the present application provides a projection device, an automatic focusing method for the projection device, and a device with a storage function, aiming at solving the problems of long focusing time and low precision.
  • the present application provides a projection device, comprising: a projection module, a driving module, a camera module, a computing module and a control module, the control module is electrically coupled to the projection module, the driving module, the camera module and the computing module;
  • the projection module is used for projecting the reference picture to the picture to be displayed to form a projection picture
  • the control module is used for controlling the driving module to drive the projection device to move, so that the projection module projects to form a plurality of projection images according to the preset time sequence, and controls the camera module to capture the projection images frame by frame according to the preset time sequence, so as to obtain a plurality of images to be analyzed;
  • the control module is also used to control the calculation module to synchronously calculate the sharpness values of each image to be analyzed when the camera module captures the projected image frame by frame, to obtain a sharpness value sequence, and to analyze two adjacent sharpness value sequences to determine the best sharpness value sequence.
  • the control module is further configured to control the driving module to drive the projection device to move in the opposite direction of the current moving direction and continue to move for the return journey time at a preset speed, so as to move the projection device to the best focus position.
  • the present application provides an automatic focusing method of a projection device, the method comprising:
  • the sharpness value of each image to be analyzed is calculated synchronously, and the sharpness value sequence is obtained;
  • the projection device is driven to move in the opposite direction of the current moving direction at a preset speed continuously for the return trip time, so that the projection device moves to the best focus position.
  • the present application provides a device with a storage function, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the aforementioned automatic focusing method are implemented.
  • the projection module of the present application projects to form a plurality of projection pictures according to a preset time sequence, and when the camera module captures the plurality of projection pictures frame by frame, the calculation module synchronously calculates the value of each image to be analyzed.
  • the sharpness value is obtained to obtain the sharpness value sequence.
  • the optimal focus position and the return time required to move to the best focus position can be determined. Since the present application can directly analyze the gradient change of image sharpness to determine the optimal focus position, no additional ranging device is required, the focus accuracy can be improved, and at the same time, it is not necessary to analyze all sharpness values before searching for the best sharpness among them.
  • the number of captured images is smaller, the focusing time is shorter, and the focusing efficiency is higher.
  • FIG. 1 is a schematic diagram of functional modules of a first embodiment of a projection device of the present application
  • FIG. 2 is a schematic diagram of functional modules of a second embodiment of the projection device of the present application.
  • FIG. 3 is a schematic diagram of functional modules of the third embodiment of the projection device of the present application.
  • FIG. 4 is a schematic diagram of functional modules of a fourth embodiment of a projection device according to the present application.
  • FIG. 5 is a schematic flowchart of the first embodiment of the automatic focusing method of the projection device of the present application
  • FIG. 6 is a schematic flowchart of a second embodiment of an automatic focusing method for a projection device of the present application
  • FIG. 7 is a schematic flowchart of a third embodiment of an automatic focusing method for a projection device of the present application.
  • FIG. 8 is a graph of the image sharpness value after filtering in the automatic focusing method of the projection device of the present application.
  • the focus processing of the existing projection equipment generally adopts the ranging method.
  • the ranging method obtains the distance information between the projector and the projection plane through sensors (mainly ranging sensors, such as TOF, infrared, ultrasonic, etc.), and then directly calculates the projection according to the pre-stored distance-best focus position comparison table The distance that the module needs to move to the best focus position, and then the drive motor drives the projection module to move to the best focus position to achieve focus.
  • sensors mainly ranging sensors, such as TOF, infrared, ultrasonic, etc.
  • this ranging method has obvious shortcomings. First, the accuracy is not enough. Second, it cannot solve the problem of projector heat.
  • FIG. 1 is a schematic diagram of functional modules of the first embodiment of the projection device of the present application.
  • the projection device 10 may be a device capable of projecting projection images, such as a projection device body (including a miniature projection device body), a laser TV, and the like.
  • the projection device 10 includes: a projection module 11 , a driving module 12 , a camera module 13 , a computing module 14 and a control module 15 .
  • the control module 15 is electrically coupled to the projection module 11 , the driving module 12 , the camera module 13 and the computing module 14 .
  • the projection module 11 is used to project the reference picture to the to-be-displayed picture to form a projection picture
  • the control module 15 is used to control the driving module 12 to drive the projection device to move, so that the projection module 11 projects to form a plurality of projection pictures according to the preset timing.
  • the projection module 11 includes a light source module, an opto-mechanical module, and a projection lens.
  • the light source module is used for providing illumination beams.
  • the optomechanical module is used to convert the illumination light beam into the image light beam.
  • the projection lens is used to convert the image beam into a projection beam, and project the projection beam to form a projection image.
  • the driving module 12 may be a focusing motor, the focusing motor is connected to the projection module 11 , and the focusing motor is used to drive the projection lens of the projection module 11 to move along the optical axis direction. Driven by the above-mentioned driving module 12 , the projection lens of the projection module 11 moves according to a preset timing while projecting a projection image onto a wall or a curtain.
  • the camera module 13 shoots and records projection images of different resolutions frame by frame according to a preset time sequence, so as to obtain a plurality of images to be analyzed.
  • the driving module 12 may be a driving rod
  • the projection device includes a fixing bracket and a support structure for fixing with an external fixing surface
  • the driving rod is arranged on the fixing bracket
  • the supporting structure is fixed on the driving rod.
  • the fixed bracket includes a main body and a fixed end that is bent and extended from the main body to both sides. The fixed end is used to fit and fix with the external fixed surface.
  • the main body includes a top wall and a bottom wall that are oppositely arranged. The wall is spaced from the fixed end.
  • the support structure extends from the drive rod to the direction away from the external fixed surface.
  • the support structure is used to support the object to be fixed.
  • the height position of the projection module 11 is continuously adjustable.
  • the height position of the support structure is continuously adjustable through the rotation of the drive rod. It is not only convenient to fix, but also convenient to realize the position adjustment along the height direction, and can effectively realize the effective adjustment of the projection effect.
  • the calculation module 14 calculates the sharpness values of each image to be analyzed synchronously to obtain a sharpness value sequence, and analyzes two adjacent sharpness value sequences to determine the optimal focus position and Return time required to move to the optimal focus position, and feed back the optimal focus position and return time to the control module 15 .
  • the control module 15 is configured to control the driving module 12 to drive the projection device 10 to move in the opposite direction of the current moving direction and continue to move for the return journey time at a preset speed until the projection device 10 moves to the best focusing position to achieve focusing.
  • the camera module 13 can be embedded in the projection device 10, so that the camera module 13 and the projection device 10 are integrated into an integrated structure, which effectively improves the standardization of the projection image by the camera module 13.
  • the accuracy of the timing ensures the reliability of the projection device 10 .
  • the calculation module 14 is configured to synchronously calculate the sharpness value SN of the image to be analyzed PN corresponding to the projected image when the camera module 13 captures the projected image frame by frame, that is, the calculation module 14 calculates the image sharpness and the camera module 13 shoots the projected image.
  • the pictures are performed at the same time, which can save the time spent by the computing module 14 in processing the images.
  • the calculation method of the sharpness value can adopt wavelet transform, Fourier transform, image grayscale gradient value, image grayscale gradient value algorithm, Tenengrad function and so on. Application environments corresponding to different algorithms are different. Preferably, the Tenengrad function may be used in this embodiment.
  • the calculation module 14 can analyze two adjacent sharpness value sequences ⁇ s 1 ,s 2 ,...,s N-1 ⁇ and ⁇ s 2 ,s 3 ,...,s N ⁇ to determine the obtained optimal focus position and the return point of the projection module 11 .
  • the control module 15 can control the projection module 11 to move from the return point at a preset speed for the return time and then return to the optimal focusing position, thereby realizing focusing.
  • the projection module 11 of the embodiment of the present application projects to form a plurality of projection images according to a preset time sequence.
  • the calculation module 14 synchronously calculates the sharpness value of each image to be analyzed. , to obtain the sharpness value sequence, and by analyzing two adjacent sharpness value sequences, the optimal focus position and the return time required to move to the best focus position can be determined. Since the present application can directly analyze the gradient change of image sharpness to determine the optimal focus position, no additional ranging device is required, the focus accuracy can be improved, and at the same time, it is not necessary to analyze all sharpness values before searching for the best sharpness among them. Compared with the prior art, the number of captured images is smaller, the focusing time is shorter, and the focusing efficiency is higher.
  • the camera module 13 is used to capture the projected image frame by frame to obtain the projected image, and extract the pixels of the desired focus area in the projected image to generate the image to be analyzed.
  • the camera module 13 shoots and records the projection picture I o corresponding to the travel position of the projection module 11 after each movement, and extracts the pixels of the required focus area in the projection picture I o to form a new image I to be analyzed t .
  • FIG. 2 is a schematic diagram of functional modules of a second embodiment of the projection apparatus of the present application.
  • the driving module 12 may be a DC motor 122 , and the DC motor 122 is connected to the projection module 11 .
  • the DC motor 122 is used to drive the projection module 11 to move at a preset speed, so that the projection module 11 projects to form a plurality of projection images according to a preset timing.
  • the output of the stepping motor is usually used to drive the projection module 11 to move to the best focus position step by step. It will oscillate back and forth a few times around the best focus position. Since a local saddle point is likely to exist in the sharpness curve, if the step size of the stepping motor is too small, the projection module 11 is likely to fall into the saddle point, resulting in failure of focusing. If the step size of the stepping motor is too large, the number of times the lens oscillates back and forth at the optimal focusing position will increase, and the focusing speed will be slowed down. Different from the prior art, the present embodiment uses the DC motor 122 to drive the projection module 11 to move.
  • the DC motor 122 directly controls the movement time of the motor by controlling the time of the high-level signal, and controls the movement time of the PWM signal.
  • the duty cycle controls the speed of the motor, so the time of the high-level signal and the duty cycle of the PWM determine the displacement of the motor, and it is not necessary to set the moving step to avoid the failure of focusing or the slow focusing speed of the stepping motor in the prior art. problem.
  • FIG. 3 is a schematic diagram of functional modules of a third embodiment of a projection device of the present application.
  • the calculation module 14 includes: a filter unit 141 , a movement direction judgment unit 142 and a return time calculation unit 143 .
  • the calculation module 14 simultaneously calculates the sharpness values of each image to be analyzed captured by the camera module 13 to obtain a sharpness value sequence.
  • the filtering unit 141 is configured to perform filtering processing on two adjacent sharpness value sequences respectively by using an average filtering method, so as to obtain two adjacent filtering values.
  • the present embodiment uses the filtering unit 141 to filter the obtained sharpness value sequence, so that the focusing method becomes more robust.
  • the filtering unit 141 may be a low-pass filter.
  • two adjacent sharpness value sequences ⁇ s 1 ,s 2 ,...,s N-1 ⁇ and ⁇ s 2 ,s 3 ,...,s N ⁇ are calculated and obtained, using the average
  • the filtering method respectively performs filtering processing on the above-mentioned two adjacent two sharpness value sequences to obtain two filtering values s' N-1 and s' N , wherein,
  • the moving direction judging unit 142 is used for judging whether two adjacent filter values are attenuated with the current moving direction of the projection module 11 , wherein, if not, it is determined that the projection module 11 should move in the opposite direction of the current moving direction.
  • the calculated value of s' N-1 -s' N if s' N-1 -s'N greater than 0, the two adjacent filter value with a current moving direction of the projector module 11 is attenuated is illustrated, this time
  • the moving direction of the projection module 11 is the direction of the best focus position, and the projection module 11 is controlled to continue to move along the current movement direction.
  • s' N-1 -s' N is less than 0, it means that the two adjacent filter values increase with the current moving direction of the projection module 11, which means that the projection module 11 has passed the best focus position, and the projection module 11 should move along the current direction. Move to the best focus position in the opposite direction of the direction.
  • the return time calculation unit 143 is configured to obtain the return time according to each resolution value and the calculation time of each resolution value.
  • the projection module 11 is controlled to stop moving, for example, the operation of the DC motor 122 may be stopped, thereby stopping the driving of the projection module 11 to continue moving.
  • Search for the maximum value in the stored sharpness sequence ⁇ s 1 , s 2 ,...,s N ⁇ , find the position d argmax(S) corresponding to the maximum value, and the position corresponding to the maximum value is the best focus position .
  • Calculate the return time required to move from the current position to the best focus position, t i is the calculation time of the sharpness value si.
  • control module 15 is further configured to control the DC motor 122 to drive the projection module 11 to move in the opposite direction of the current moving direction at a preset speed for the return journey time T, so as to move the projection module 11 to the best focus position.
  • FIG. 4 is a schematic diagram of functional modules of a fourth embodiment of a projection device of the present application.
  • the calculation module 14 further includes a sharpness calculation unit 144, and the sharpness calculation unit 144 is configured to calculate the sharpness value of each image to be analyzed according to the sharpness evaluation function.
  • the evaluation function of the Tenengrad gradient algorithm is used to calculate the sharpness value s of each image to be analyzed, wherein,
  • S x (x, y) and S y (x, y) represent the value of the image to be analyzed convolved with the Sobel edge operator at the pixel point (x, y), the Sobel edge operator in the x-axis direction and y There is one for each axis direction.
  • the calculation method of this embodiment balances the calculation speed and effect, ensures the unimodality of the sharpness curve, and quickly evaluates the sharpness of the image to be analyzed.
  • the projection module 11 collects and processes more sequence images within the range that the projection module 11 can move, which ensures the density of the sharpness curve.
  • FIG. 5 is a schematic flowchart of a first embodiment of an automatic focusing method for a projection device of the present application.
  • the automatic focusing method of the projection device of the present application is based on the projection device 10 in the above-mentioned embodiment.
  • the projection device please refer to the above-mentioned embodiment, which will not be repeated here.
  • the automatic focusing method of the projection device includes the following steps:
  • S11 Drive the projection device to move at a preset speed, so that the projection module provided in the projection device projects the reference picture to the to-be-displayed picture according to the preset time sequence to form a plurality of projection pictures.
  • S12 Capture the projection images frame by frame according to a preset time sequence to obtain a plurality of images to be analyzed.
  • S14 Analyze two adjacent sharpness value sequences to determine the best focus position and the return travel time required to move to the best focus position.
  • S15 Drive the projection device to move in the opposite direction of the current movement direction and continue to move for the return journey time at a preset speed, so as to move the projection device to the best focus position.
  • the projection module moves according to the preset timing while projecting the projection image onto the wall or the curtain. It can be understood that, with the movement of the projection lens, the clarity of the projection image is also different. Shoot and record projection images of different resolutions frame by frame according to the preset timing, and obtain multiple images to be analyzed.
  • the sharpness value SN of the image PN to be analyzed corresponding to the projected image is calculated synchronously, that is, the image sharpness is calculated and the projection image is captured at the same time, which can save the time spent processing the image.
  • the calculation method of the sharpness value can adopt wavelet transform, Fourier transform, image grayscale gradient value, image grayscale gradient value algorithm, Tenengrad function and so on. Application environments corresponding to different algorithms are different. Preferably, the Tenengrad function may be used in this embodiment. Further, since the sharpness value curve is unimodal, two adjacent sharpness value sequences ⁇ s 1 ,s 2 ,...,s N-1 ⁇ and ⁇ s 2 ,s 3 ,..., s N ⁇ to determine the resulting best focus position and the return point of the camera module. At this time, the camera module can be controlled to move from the return point to the return time and then return to the optimal focusing position, thereby realizing focusing.
  • the projection module of the embodiment of the present application projects to form a plurality of projection images according to a preset time sequence, and when capturing the plurality of projection images frame by frame, synchronously calculates the sharpness values of each image to be analyzed, so as to obtain a sharpness value sequence , by analyzing two adjacent sharpness value sequences, the best focus position and the return time required to move to the best focus position can be determined. Since the present application can directly analyze the gradient change of image sharpness to determine the optimal focus position, no additional ranging device is required, the focus accuracy can be improved, and at the same time, it is not necessary to analyze all sharpness values before searching for the best sharpness among them. Compared with the prior art, the number of captured images is smaller, the focusing time is shorter, and the focusing efficiency is higher.
  • FIG. 6 is a schematic flowchart of a second embodiment of an automatic focusing method for a projection device of the present application.
  • Step S12 specifically includes the following steps:
  • S121 Capture the projected image frame by frame to obtain a projected image, and extract the pixels of the required focus area in the projected image to generate an image to be analyzed.
  • FIG. 7 is a schematic flowchart of a third embodiment of an automatic focusing method for a projection device of the present application.
  • Step S11 specifically includes the following steps:
  • S111 Drive the projection module to move at a preset speed by a DC motor, so that the projection module projects a reference picture to a to-be-displayed picture according to a preset time sequence to form a plurality of projection pictures.
  • the DC motor starts to drive the camera module to move, and at the same time, the camera module shoots and records the projection picture I o corresponding to the travel position of the camera module after each movement, and extracts the pixels of the required focus area in the projection picture I o to form the new images to be analyzed I t.
  • the DC motor directly controls the motion time of the motor by controlling the time of the high-level signal, and controls the speed of the motor by controlling the duty cycle of the PWM signal, so the time of the high-level signal and the duty cycle of the PWM determine the displacement of the motor, not
  • the moving step length needs to be set to avoid the problems of failure of focusing or slow focusing speed of the stepping motor in the prior art.
  • Step S14 specifically includes the following steps:
  • S141 Use the average filtering method to filter two adjacent sharpness value sequences ⁇ s 1 ,s 2 ,...,s N ⁇ and ⁇ s 2 ,s 3 ,...,s N+1 ⁇ respectively, to obtain Two adjacent filter values s' N-1 and s' N .
  • S142 Determine whether two adjacent filter values are attenuated with the current moving direction of the projection module.
  • two adjacent sharpness value sequences ⁇ s 1 ,s 2 ,...,s N ⁇ and ⁇ s 2 ,s 3 ,...,s N+1 ⁇ are obtained by calculation, using The N-point average filtering method respectively filters the two adjacent sharpness value sequences to obtain two filter values s' N-1 and s' N , where,
  • s' N-1 -s' N Calculate the value of s' N-1 -s' N. If it is greater than 0, it means that the two adjacent filter values are attenuated with the current moving direction of the projection module. At this time, the moving direction of the projection module is the direction of the best focus position. , control the projection module to continue to move along the current moving direction.
  • s' N-1 -s' N is less than 0, it means that the two adjacent filter values increase with the current moving direction of the projection module, which means that the projection module has passed the best focus position, and the projection module should move in the opposite direction of the current movement direction. direction to the best focus position.
  • t i is the calculation time of the sharpness value si.
  • the projection module is controlled to stop moving, for example, the operation of the DC motor can be stopped, thereby stopping the driving of the projection module to continue moving.
  • Search for the maximum value in the stored sharpness sequence ⁇ s 1 , s 2 ,...,s N ⁇ , find the position d argmax(S) corresponding to the maximum value, and the position corresponding to the maximum value is the best focus position .
  • Calculate the return time required to move from the current position to the best focus position d, t i is the calculation time of the sharpness value si.
  • the original image sharpness value curve is unimodal, but there are many local saddle points.
  • the filtered curve becomes smooth by averaging, and the optimal focus position of the projection module can be smoothly passed when the gradient of the filtered curve is calculated.
  • the corresponding return point and the best focus position can be found (the sharpness curve in FIG. 8 depicts the sharpness range within the moving range of the projection module).
  • the return time T can be calculated according to step S145. As can be seen from Figure 8, assuming that the initial position of the projection module is at the far left of the image curve, the total time spent in focusing in this example is approximately equal to the time required to calculate about 50 frames of images. If the average time to calculate one frame of image is 20ms, then The total time for autofocusing this time is about 1s.
  • Step S15 specifically includes the following steps:
  • Step S151 Drive the projection module to move continuously for the return time T at a preset speed along the opposite direction of the current movement direction, so as to move the projection module to the best focus position.
  • step S13 further includes: when moving the captured projection picture, calculating the sharpness value s of each image to be analyzed according to the sharpness evaluation function,
  • S x (x, y) and S y (x, y) are obtained by the Sobel edge detection operator and image convolution.
  • the calculation method of this embodiment balances the calculation speed and effect, ensures the unimodality of the sharpness curve, and quickly evaluates the sharpness of the image to be analyzed.
  • the module can collect and process more sequence images within the moving range, which ensures the density of the definition curve.
  • the present application also provides a device with a storage function.
  • a computer program is stored on the device, and when the computer program is executed by the processor, the steps of the automatic focusing method of the aforementioned projection device are realized.
  • the specific process please refer to the above-mentioned embodiment, which will not be repeated here.
  • the present application uses a device with a storage function to store a program for storing the program executed by the processor and the intermediate data generated when the program is executed, so as to facilitate the user to store data in advance.
  • the disclosed methods and apparatuses may be implemented in other manners.
  • the apparatus implementations described above are only illustrative, for example, the division of modules or units is only a logical function division, and other divisions may be used in actual implementation, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • Units described as separate components may or may not be physically separated, and components shown as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this implementation manner.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.
  • the integrated unit if implemented as a software functional unit and sold or used as a stand-alone product, may be stored in a computer-readable storage medium.
  • the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the methods of the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), server, magnetic disk or optical disk and other various programs that can store program codes medium.

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
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Abstract

本申请涉及投影技术领域，具体公开了一种投影设备、自动对焦方法以及具有存储功能的装置，该投影设备的控制模块控制驱动模块驱动投影设备移动，以使投影模块按预设时序投射形成多个投影画面，并控制摄像模块按预设时序摄取多个投影画面，以得到多个待分析图像；控制模块还用于控制计算模块在摄像模块逐帧摄取投影画面时，同步计算各个待分析图像的清晰度值，得到清晰度值序列，并分析相邻的两个清晰度值序列，以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间；控制模块还用于控制驱动模块驱动投影设备沿当前移动方向的反方向以预设速度持续移动返程时间。通过上述方式，能够提高对焦精度，并缩短对焦时间。

Description

投影设备、投影设备的自动对焦方法以及装置 技术领域
本申请涉及投影技术领域，特别是涉及一种投影设备、投影设备的自动对焦方法以及装置。
背景技术
投影设备一般用于投射与之连接的相关设备上所显示的界面图像，比如投射电脑、手机设备屏幕上所显示的界面图像等。
本申请的发明人在长期的研发过程中，发现由于现有技术中存在一些自动对焦方法，如采用额外的测距装置，测量屏幕与投影机之间的距离，根据距离与焦距的关系驱动马达移动投影镜头到指定的位置，但是这种方式对焦精度差，且对焦过程所花时间较长，进而影响用户使用体验。
发明内容
本申请提供一种投影设备、投影设备的自动对焦方法以及具有存储功能的装置，旨在解决对焦时间过长且精度不高的问题。
一方面，本申请提供了一种投影设备，包括：投影模块、驱动模块、摄像模块、计算模块以及控制模块，控制模块电性耦接投影模块、驱动模块、摄像模块以及计算模块；
投影模块用于将参考图片投射到待显示画面处以形成投影画面；
控制模块用于控制驱动模块驱动投影设备移动，以使投影模块按预设时序投射形成多个投影画面，并控制摄像模块按预设时序逐帧摄取投影画面，以得到多个待分析图像；
控制模块还用于控制计算模块在摄像模块逐帧摄取投影画面时，同步计算各个待分析图像的清晰度值，得到清晰度值序列，并分析相邻的 两个清晰度值序列，以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间；
控制模块还用于控制驱动模块驱动投影设备沿当前移动方向的反方向以预设速度持续移动返程时间，以使投影设备移动到最佳对焦位置。
另一方面，本申请提供了一种投影设备的自动对焦方法，该方法包括：
驱动投影设备以预设速度移动，以使投影设备其内设置的投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面；
按预设时序逐帧摄取投影画面，以得到多个待分析图像；
在逐帧摄取投影画面时，同步计算各个待分析图像的清晰度值，得到清晰度值序列；
分析相邻的两个清晰度值序列，以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间；
驱动投影设备沿当前移动方向的反方向以预设速度持续移动返程时间，以使投影设备移动到最佳对焦位置。
又一方面，本申请提供了一种具有存储功能的装置，其上存储有计算机程序，计算机程序被处理器执行时实现如前述的自动对焦方法的步骤。
本申请提供的技术方案可以达到以下有益效果：本申请的投影模块按预设时序投射形成多个投影画面，在摄像模块逐帧摄取该多个投影画面时，计算模块同步计算各个待分析图像的清晰度值，以得到清晰度值序列，通过分析相邻的两个清晰度值序列，可以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间。由于本申请直接分析图像清晰度的梯度变化即可确定最佳对焦位置，不需要采用额外的测距装置，能够提高对焦精度，同时不需要分析全部清晰度值后再搜索当中的最佳清晰度值，与现有技术相比摄取图像数量更少、对焦时间更短、对焦效率更高。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。其中：
图1为本申请投影设备第一实施例的功能模块示意图；
图2为本申请投影设备第二实施例的功能模块示意图；
图3为本申请投影设备第三实施例的功能模块示意图
图4为本申请投影设备第四实施例的功能模块示意图；
图5为本申请投影设备的自动对焦方法第一实施例的流程示意图；
图6为本申请投影设备的自动对焦方法第二实施例的流程示意图；
图7为本申请投影设备的自动对焦方法第三实施例的流程示意图；
图8为本申请投影设备的自动对焦方法中滤波后的图像清晰度值曲线图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性的劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
现有投影设备的对焦处理一般采用测距法。测距法通过传感器(主要是测距类传感器，如TOF，红外，超声波等)获得投影机与投影平面的距离信息，然后根据预先所存的距离-最佳对焦位置对照表，直接计算得出投影模块所需移动到最佳对焦位置的距离，然后驱动电机带动投影模块位移到最佳对焦位置进而实现对焦，但这种测距法的缺点明显，一是精度不够，二是无法解决投影机热失焦的问题，投影热失焦时，投影模块的位置并没有改变，但所对应的最佳对焦位置因为光学仪器的膨胀而发生了位移，此时便失去了能够参考的距离信息，导致测距法失效。
为解决现有技术存在的技术问题，本申请提供一种投影设备，参照 图1，图1为本申请投影设备第一实施例的功能模块示意图。本实施例中，投影设备10可以是投影设备本体(包括微型投影设备本体)和激光电视等能够投射投影画面的设备。投影设备10包括：投影模块11、驱动模块12、摄像模块13、计算模块14以及控制模块15。控制模块15电性耦接投影模块11、驱动模块12、摄像模块13以及计算模块14。
投影模块11用于将参考图片投射到待显示画面处以形成投影画面，控制模块15用于控制驱动模块12驱动投影设备移动，以使投影模块11按预设时序投射形成多个投影画面。
具体地，投影模块11包括光源模块、光机模块以及投影镜头。光源模块用以提供照明光束。光机模块用以将照明光束转换成影像光束。投影镜头用以将影像光束转换成投影光束，并将投影光束投射出以形成投影画面。驱动模块12可以为调焦马达，调焦马达连接投影模块11，该调焦马达用于驱动投影模块11的投影镜头沿光轴方向移动。在上述驱动模块12的驱动下，投影模块11的投影镜头按预设时序一边移动一边向墙面或者幕布上投射投影画面。可以理解的是，随着投影镜头的移动，投影画面的清晰度也有不同。摄像模块13按预设时序逐帧拍摄并记录不同清晰度的投影画面，得到多个待分析图像。
在其他实施例中，驱动模块12可以为驱动杆，投影设备包括用于与外界固定面固定的固定支架和支撑结构，驱动杆设置在固定支架上，且支撑结构固定在驱动杆上。固定支架包括主体部以及自主体部向两侧弯折延伸的固定端，固定端用于与外界固定面相贴合并固定，主体部包括相对设置的顶壁和底壁，驱动杆贯穿顶壁与底壁并与固定端间隔设置，支撑结构自驱动杆向远离外界固定面方向延伸，支撑结构用于支撑待固定物，通过驱动杆的旋转实现支撑结构的高度位置连续可调，进而使投影设备的投影模块11的高度位置连续可调。通过驱动杆的旋转实现支撑结构的高度位置连续可调。不仅方便固定，而且方便实现沿高度方向上的位置调节，可以有效实现对投影效果的有效调节。
在摄像模块13逐帧摄取投影画面时，计算模块14同步计算各个待分析图像的清晰度值，得到清晰度值序列，并分析相邻的两个清晰度值 序列，以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间，并将最佳对焦位置和返程时间反馈给控制模块15。控制模块15用于控制驱动模块12驱动投影设备10沿当前移动方向的反方向以预设速度持续移动返程时间，直至投影设备10移动到最佳对焦位置，以实现对焦。
为了进一步提高投影设备10和摄像模块13安装的稳定性，可以将摄像模块13嵌入投影设备10中，使摄像模块13和投影设备10成为一体结构，有效地提高了摄像模块13对投影画面进行标定时的准确性，保证了投影设备10的可靠性。
具体地，计算模块14用于在摄像模块13逐帧摄取投影画面时，同步计算该投影画面对应的待分析图像PN的清晰度值SN，即计算模块14计算图像清晰度与摄像模块13拍摄投影画面是同时进行的，这样可以节省计算模块14处理图像所耗费的时间。
其中清晰度值的计算方法可以采用有小波变换、傅立叶变换、图像灰度梯度值、图像灰度梯度值算法、Tenengrad函数等。不同算法所对应的应用环境不同，优选地，本实施例可以采用Tenengrad函数。进一步地，由于清晰度值曲线具有单峰性的特点，计算模块14可以分析相邻的两个清晰度值序列{s 1,s 2,…,s N-1}和{s 2,s 3,…,s N}，以确定得到的最佳对焦位置和投影模块11的返程点。此时，控制模块15可以控制投影模块11从返程点以预设速度移动返程时间后回到最佳对焦位置，进而实现对焦。
通过上述方式，本申请实施例的投影模块11按预设时序投射形成多个投影画面，在摄像模块13逐帧摄取该多个投影画面时，计算模块14同步计算各个待分析图像的清晰度值，以得到清晰度值序列，通过分析相邻的两个清晰度值序列，可以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间。由于本申请直接分析图像清晰度的梯度变化即可确定最佳对焦位置，不需要采用额外的测距装置，能够提高对焦精度，同时不需要分析全部清晰度值后再搜索当中的最佳清晰度值，与现有技术相比摄取图像数量更少、对焦时间更短、对焦效率更高。
在一实施例中，摄像模块13用于逐帧摄取投影画面，以获得投影 图像，并提取投影图像中所需对焦区域的像素，以生成待分析图像。
具体地，摄像模块13逐帧拍摄并记录投影模块11在每次移动后所在行程位置所对应的投影画面I o，并提取投影画面I o中所需对焦区域的像素形成新的待分析图像I t。
参照图2，图2为本申请投影设备第二实施例的功能模块示意图。在一实施例中，驱动模块12可以为直流电机122，直流电机122连接投影模块11。
直流电机122用于驱动投影模块11以预设速度移动，以使投影模块11按预设时序投射形成多个投影画面。
需要说明的是，现有技术中通常是通过步进电机的输出以带动投影模块11一步一步地移动到最佳对焦位置，但本申请发明人发现，要达到比较理想的对焦位置，投影模块11会在最佳对焦位置附近来回震荡几次。由于清晰度曲线易存在局部鞍点，若步进电机的步长过小，则投影模块11容易陷入鞍点中，导致对焦失败。若步进电机的步长过大，则会增大镜头在最佳对焦位置来回震荡的次数，减慢对焦速度。区别于现有技术，本实施例采用直流电机122驱动投影模块11移动，与步进电机的控制不同的是，直流电机122通过控制高平信号的时间直接控制电机的运动时间，通过控制PWM信号的占空比控制电机的转速，所以高平信号的时间和PWM的占空比决定了电机的位移量，并不需要设置移动步长，避免出现现有技术中步进电机对焦失败或对焦速度慢的问题。
参照图3，图3为本申请投影设备第三实施例的功能模块示意图。计算模块14包括：滤波单元141、移动方向判断单元142以及返程时间计算单元143。
计算模块14同步计算摄像模块13摄取的各个待分析图像的清晰度值，以得到清晰度值序列。
滤波单元141用于采用平均滤波法分别对相邻的两个清晰度值序列进行滤波处理，以得到相邻的两个滤波值。
具体地，为了消除清晰度曲线中的局部鞍点，进而避免投影模块11陷入鞍点，本实施例使用滤波单元141对所得到的清晰度值序列做滤波 处理，使得对焦方法变得更为鲁棒。优选地，滤波单元141可以为低通滤波器。
N次摄取所述投影画面后，计算得到相邻的两个清晰度值序列{s 1,s 2,…,s N-1}和{s 2,s 3,…,s N}，使用平均滤波法分别对上述两个相邻的两个清晰度值序列进行滤波处理后，得到两个滤波值s’ N-1和s’ N，其中，
Figure PCTCN2021103973-appb-000001
移动方向判断单元142用于判断相邻的两个滤波值是否随投影模块11当前移动方向而衰减，其中，若否则判定投影模块11应沿当前移动方向的反方向移动。
具体地，计算s’ N-1-s’ N的值，如果s’ N-1-s’N大于0，则说明相邻的两个滤波值随投影模块11当前移动方向而衰减，此时投影模块11所移动的方向是最佳对焦位置的方向，控制投影模块11继续沿当前移动方向移动。当s’ N-1-s’ N小于0，说明相邻的两个滤波值随投影模块11当前移动方向而递增，说明投影模块11已走过最佳对焦位置，投影模块11应沿当前移动方向的反方向移动到最佳对焦位置。
返程时间计算单元143用于根据各个清晰度值和各个清晰度值的计算时间得到返程时间。
具体地，当s’ N-1-s’ N小于0时，控制投影模块11停止移动，例如，可以停止直流电机122工作，进而停止驱动投影模块11继续移动。搜索所储存清晰度序列{s 1,s 2,…,s N}中的最大值，找到最大值所对应的位置d＝argmax(S)，该最大值所对应的位置即为最佳对焦位置。计算从当前位置移动到最佳对焦位置所需的返程时间，
Figure PCTCN2021103973-appb-000002
t i为清晰度值s i的计算时间。
进一步地，控制模块15还用于控制直流电机122驱动投影模块11沿当前移动方向的反方向以预设速度持续移动返程时间T，以使投影模块11移动到最佳对焦位置。
参照图4，图4为本申请投影设备第四实施例的功能模块示意图。计算模块14还包括清晰度计算单元144，清晰度计算单元144用于根据清晰度评价函数计算各个待分析图像的清晰度值。
具体地，运用Tenengrad梯度算法的评价函数计算各个待分析图像的清晰度值s，其中，
Figure PCTCN2021103973-appb-000003
其中，S x(x,y)和S y(x,y)表示待分析图像与Sobel边缘算子卷积在像素点(x,y)处的值，Sobel边缘算子在x轴方向和y轴方向各有一个。
本实施例的计算方法权衡了计算速度和效果，保证了清晰度曲线单峰性的同时，快速的对待分析图像进行清晰度评价，运算复杂度更低，耗时更少，使计算模块14在投影模块11所能移动的范围内采集处理更多的序列图像，保证了清晰度曲线的稠密性。
参照图5，图5为本申请投影设备的自动对焦方法第一实施例的流程示意图。本申请投影设备的自动对焦方法基于上述实施例中的投影设备10，关于投影设备的具体描述请参照上述实施例，在此不做赘述。
该投影设备的自动对焦方法包括以下步骤：
S11：驱动投影设备以预设速度移动，以使投影设备其内设置的投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面。
S12：按预设时序逐帧摄取投影画面，以得到多个待分析图像。
S13：在逐帧摄取投影画面时，同步计算各个待分析图像的清晰度值，得到清晰度值序列。
S14：分析相邻的两个清晰度值序列，以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间。
S15：驱动投影设备沿当前移动方向的反方向以预设速度持续移动返程时间，以使投影设备移动到最佳对焦位置。
具体地，在驱动模块的驱动下，投影模块按预设时序一边移动一边向墙面或者幕布上投射投影画面。可以理解的是，随着投影镜头的移动，投影画面的清晰度也有不同。按预设时序逐帧拍摄并记录不同清晰度的投影画面，得到多个待分析图像。
在逐帧摄取投影画面时，同步计算该投影画面对应的待分析图像PN的清晰度值SN，即计算图像清晰度与拍摄投影画面是同时进行的，这 样可以节省处理图像所耗费的时间。
其中清晰度值的计算方法可以采用有小波变换、傅立叶变换、图像灰度梯度值、图像灰度梯度值算法、Tenengrad函数等。不同算法所对应的应用环境不同，优选地，本实施例可以采用Tenengrad函数。进一步地，由于清晰度值曲线具有单峰性的特点，可以分析相邻的两个清晰度值序列{s 1,s 2,…,s N-1}和{s 2,s 3,…,s N}，以确定得到的最佳对焦位置和摄像模块的返程点。此时，可以控制摄像模块从返程点移动返程时间后回到最佳对焦位置，进而实现对焦。
通过上述方式，本申请实施例的投影模块按预设时序投射形成多个投影画面，在逐帧摄取该多个投影画面时，同步计算各个待分析图像的清晰度值，以得到清晰度值序列，通过分析相邻的两个清晰度值序列，可以确定最佳对焦位置以及移动到最佳对焦位置所需的返程时间。由于本申请直接分析图像清晰度的梯度变化即可确定最佳对焦位置，不需要采用额外的测距装置，能够提高对焦精度，同时不需要分析全部清晰度值后再搜索当中的最佳清晰度值，与现有技术相比摄取图像数量更少、对焦时间更短、对焦效率更高。
参照图6，图6是本申请投影设备的自动对焦方法第二实施例的流程示意图。步骤S12具体包括以下步骤：
S121：逐帧摄取投影画面，以获得投影图像，并提取投影图像中所需对焦区域的像素，以生成待分析图像。
参照图7，图7本申请投影设备的自动对焦方法第三实施例的流程示意图。步骤S11具体包括以下步骤：
S111：通过直流电机驱动所述投影模块以预设速度移动，以使所述投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面。
具体地，直流电机开始驱动摄像模块移动，同时，摄像模块拍摄并记录摄像模块在每次移动后所在行程位置所对应的投影画面I o，并提取投影画面I o中所需对焦区域的像素形成新的待分析图像I t。
其中，直流电机通过控制高平信号的时间直接控制电机的运动时间， 通过控制PWM信号的占空比控制电机的转速，所以高平信号的时间和PWM的占空比决定了电机的位移量，并不需要设置移动步长，避免出现现有技术中步进电机对焦失败或对焦速度慢的问题。
步骤S14具体包括以下步骤：
S141：采用平均滤波法分别对相邻的两个清晰度值序列{s 1,s 2,…,s N}和{s 2,s 3,…,s N+1}进行滤波处理，以得到相邻的两个滤波值s’ N-1和s’ N。
其中，
Figure PCTCN2021103973-appb-000004
S142：判断相邻的两个滤波值是否随投影模块当前移动方向而衰减。
若s’ N-1-s’ N小于0，则判定投影模块应沿当前移动方向的反方向移动。
具体地，N次摄取投影画面后，计算得到相邻的两个清晰度值序列{s 1,s 2,…,s N}和{s 2,s 3,…,s N+1}，使用N点平均滤波法分别对上述两个相邻的两个清晰度值序列进行滤波处理后，得到两个滤波值s’ N-1和s’ N，其中，
Figure PCTCN2021103973-appb-000005
计算s’ N-1-s’ N的值，如果大于0，则说明相邻的两个滤波值随投影模块当前移动方向而衰减，此时投影模块所移动的方向是最佳对焦位置的方向，控制投影模块继续沿当前移动方向移动。当s’ N-1-s’ N小于0，说明相邻的两个滤波值随投影模块当前移动方向而递增，说明投影模块已走过最佳对焦位置，投影模块应沿当前移动方向的反方向移动到最佳对焦位置。
S143：当s’ N-1-s’ N<0时，停止驱动投影模块移动并搜索清晰度序列{s 1,s 2,…,s N}的中最大值。
其中，最大值所对应的位置d＝argmax(S)。
S144：计算返程时间T。
其中，
Figure PCTCN2021103973-appb-000006
t i为清晰度值s i的计算时间。
具体地，当s’ N-1-s’ N小于0时，控制投影模块停止移动，例如，可以停止直流电机工作，进而停止驱动投影模块继续移动。搜索所储存清晰度序列{s 1,s 2,…,s N}中的最大值，找到最大值所对应的位置d＝argmax(S)，该最大值所对应的位置即为最佳对焦位置。计算从当前位 置移动到最佳对焦位置d所需的返程时间，
Figure PCTCN2021103973-appb-000007
t i为清晰度值s i的计算时间。
如图8所示，原始的图像清晰度值曲线是单峰性，但存在不少局部鞍点。通过平均滤波后的曲线变得平滑，计算该滤波后的曲线的梯度时能够顺利走过投影模块的最佳对焦位置。根据步骤S143和S144，可找到对应的返程点和最佳对焦位置(图8中的清晰度曲线描绘了投影模块移动范围内的清晰度范围)。返程时间T可以根据步骤S145计算得出。由图8可看出，假设投影模块的初始位置在图像曲线的最左端，此例子对焦所耗费的总时间约等于计算50帧图像左右的时间，如果计算一帧图像的平均时间为20ms，则本次自动对焦总耗时为1s左右。
步骤S15具体包括以下步骤：
步骤S151：驱动投影模块沿当前移动方向的反方向以预设速度持续移动返程时间T，以使投影模块移动到最佳对焦位置。
在一实施例中，步骤S13还包括：在移动摄取投影画面时，根据清晰度评价函数计算各个待分析图像的清晰度值s，
Figure PCTCN2021103973-appb-000008
其中，S x(x,y)和S y(x,y)由Sobel边缘检测算子和图像卷积得到。
具体地，运用Tenengrad梯度算法的评价函数计算各个待分析图像的清晰度值s，上述式中S x(x,y)和S y(x,y)表示待分析图像与Sobel边缘算子卷积在像素点(x,y)处的值，Sobel边缘算子在x轴方向和y轴方向各有一个。
本实施例的计算方法权衡了计算速度和效果，保证了清晰度曲线单峰性的同时，快速的对待分析图像进行清晰度评价，运算复杂度更低，耗时更少，使计算模块在摄像模块所能移动的范围内采集处理更多的序列图像，保证了清晰度曲线的稠密性。
本申请还提供一种具有存储功能的装置。该装置上存储有计算机程序，计算机程序被处理器执行时实现如前述投影设备的自动对焦方法的步骤。具体过程请参见上述实施例，在此不做赘述。
通过上述描述可知，本申请通过具有存储功能的装置存储程序，用于存储处理器执行的程序以及在执行程序时所产生的中间数据，便于用户预先存储数据。应该理解到，在本申请所提供的几个实施例中，所揭露的方法和装置，可以通过其它的方式实现。例如，以上所描述的装置实施方式仅仅是示意性的，例如，模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个***，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施方式方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器(processor)执行本申请各个实施方式方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、服务器、磁碟或者光盘等各种可以存储程序代码的介质。
以上仅为本申请的实施方式，并非因此限制本申请的专利范围，凡 是利用本申请说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。

Claims (11)

  1. 一种投影设备，其特征在于，包括：投影模块、驱动模块、摄像模块、计算模块以及控制模块，所述控制模块电性耦接所述投影模块、所述驱动模块、所述摄像模块以及所述计算模块；
    所述投影模块用于将参考图片投射到待显示画面处以形成投影画面；
    所述控制模块用于控制所述驱动模块驱动所述投影设备移动，以使所述投影模块按预设时序投射形成多个所述投影画面，并控制所述摄像模块按所述预设时序逐帧摄取所述投影画面，以得到多个待分析图像；
    所述控制模块还用于控制所述计算模块在所述摄像模块逐帧摄取所述投影画面时，同步计算各个所述待分析图像的清晰度值，得到清晰度值序列，并分析相邻的两个所述清晰度值序列，以确定最佳对焦位置以及移动到所述最佳对焦位置所需的返程时间；
    所述控制模块还用于控制所述驱动模块驱动所述投影设备沿当前移动方向的反方向以所述预设速度持续移动所述返程时间，以使所述投影设备移动到所述最佳对焦位置。
  2. 根据权利要求1所述的投影设备，其特征在于，所述摄像模块用于逐帧摄取所述投影画面，以获得投影图像，并提取所述投影图像中所需对焦区域的像素，以生成所述待分析图像。
  3. 根据权利要求1所述的投影设备，其特征在于，所述驱动模块为直流电机；
    所述控制模块用于控制所述直流电机驱动所述投影模块以预设速度移动，以使所述投影模块按预设时序投射形成多个所述投影画面。
  4. 根据权利要求3所述的投影设备，其特征在于，所述计算模块包括：
    滤波单元，用于采用平均滤波法分别对相邻的两个所述清晰度值序列进行滤波处理，以得到相邻的两个滤波值；
    移动方向判断单元，用于判断相邻的两个所述滤波值是否随所述投 影模块当前移动方向而衰减，其中，若否，则判定所述投影模块应沿当前移动方向的反方向移动；
    返程时间计算单元，用于根据各个所述清晰度值和各个所述清晰度值的计算时间得到所述返程时间；
    所述控制模块还用于控制所述直流电机驱动所述投影模块沿当前移动方向的反方向以所述预设速度持续移动所述返程时间，以使所述投影模块移动到所述最佳对焦位置。
  5. 根据权利要求4所述的投影设备，其特征在于，所述计算模块还包括：
    清晰度计算单元，用于根据清晰度评价函数计算各个所述待分析图像的清晰度值。
  6. 根据权利要求4所述的投影设备，其特征在于，所述滤波单元为低通滤波器。
  7. 一种投影设备的自动对焦方法，其特征在于，所述方法包括：
    驱动所述投影设备以预设速度移动，以使所述投影设备其内设置的投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面；
    按所述预设时序逐帧摄取所述投影画面，以得到多个待分析图像；
    在逐帧摄取所述投影画面时，同步计算各个所述待分析图像的清晰度值，得到清晰度值序列；
    分析相邻的两个所述清晰度值序列，以确定最佳对焦位置以及移动到所述最佳对焦位置所需的返程时间；
    驱动所述投影设备沿当前移动方向的反方向以所述预设速度持续移动所述返程时间，以使所述投影设备移动到所述最佳对焦位置。
  8. 根据权利要求7所述的方法，其特征在于，所述按所述预设时序逐帧摄取所述投影画面，以得到多个待分析图像的步骤，包括：
    逐帧摄取所述投影画面，以获得投影图像，并提取所述投影图像中所需对焦区域的像素，以生成所述待分析图像。
  9. 根据权利要求7所述的方法，其特征在于，所述驱动所述投影设 备以预设速度移动，以使所述投影设备其内设置的投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面的步骤，包括：
    通过直流电机驱动所述投影模块以预设速度移动，以使所述投影模块按预设时序将参考图片投射到待显示画面处以形成多个投影画面；
    所述分析相邻的两个所述清晰度值序列，以确定最佳对焦位置的步骤，包括：
    采用平均滤波法分别对相邻的两个所述清晰度值序列{s 1,s 2,…,s N-1}和{s 2,s 3,…,s N}进行滤波处理，以得到相邻的两个滤波值s’ N-1和s’ N，
    其中，
    Figure PCTCN2021103973-appb-100001
    判断相邻的两个所述滤波值是否随所述投影模块当前移动方向而衰减，其中，若s’ N-1-s’ N小于0，则判定所述投影模块应沿当前移动方向的反方向移动；
    当s’ N-1-s’ N小于0时，停止驱动所述投影模块移动并搜索清晰度序列{s 1,s 2,…,s N}的中最大值，其中，最大值所对应的位置d＝argmax(S)；
    计算所述返程时间T，其中，
    Figure PCTCN2021103973-appb-100002
    t i为所述清晰度值s i的计算时间；
    所述驱动所述投影设备移动到所述最佳对焦位置的步骤包括：
    驱动所述投影模块沿当前移动方向的反方向以所述预设速度持续移动所述返程时间T，以使所述投影模块移动到所述最佳对焦位置。
  10. 根据权利要求7所述的方法，其特征在于，在摄取所述投影画面时，同步计算各个所述待分析图像的清晰度值，得到清晰度值序列的步骤，包括：
    在摄取所述投影画面时，根据清晰度评价函数计算各个所述待分析图像的清晰度值s，
    Figure PCTCN2021103973-appb-100003
    其中，S x(x,y)和S y(x,y)由Sobel边缘检测算子和图像卷积得到。
  11. 一种具有存储功能的装置，其上存储有计算机程序，其特征在于， 所述计算机程序被处理器执行时实现如权利要求7-10中任意一项所述的投影设备的自动对焦方法的步骤。
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