CN111128046A - Lens-free imaging device and method of LED display screen - Google Patents

Abstract

The invention discloses a lens-free imaging device and method of an LED display screen. A layer of diffuser is arranged in front of the LED display screen, light on an object is scattered by the diffuser and then projected on the LED display screen, meanwhile, the LEDs on the display screen are additionally provided with a photoelectric sensing function and a corresponding receiving circuit besides a light-emitting function, when the LEDs are in a photoelectric sensing receiving state, the light intensity of the external object projected on the screen can be sensed on the LEDs, and light sensing information of all the LEDs is collected to obtain light signal distribution on the surface of the whole screen; the acquired information is transmitted to image information recovery processing equipment through a communication bus to perform image recovery through imaging calculation, so that the imaging of the object can be realized. The invention reserves the display function of the LED display screen, simultaneously enables the screen to have the capability of lens-free imaging, and can also be matched with other unit boards only having the display function to obtain the display screen integrating display and imaging.

Description

A lensless imaging device and method for an LED display screen

technical field

The present invention relates to a lensless imaging method and device, in particular to a lensless imaging device and method for an LED display screen.

Background technique

With the development of technology, LED display has been greatly applied in the aspect of large screens by using the splicing method of unit boards. Billboards, outdoor giant screens, concerts, and event background screens all use LEDs. The screen is spliced together. On the other hand, with the application of OLED display screens in mobile phone displays, the miniaturization of LEDs is also in the research stage. LEDs have a higher color gamut than OLEDs and have great potential in the field of small screen displays in the future. Micro- LED display technology is considered as a possible technology for the next generation of mobile phone screens.

In addition, the traditional imaging method requires a large and expensive lens device in front of the sensing device, while the diffuser-based lensless imaging method uses a thin and transparent diffuser film instead of the lens to achieve imaging , after receiving the initial image of the sensing device, the image can be realized only by restoring the image through the algorithm. It is smaller and lighter than the traditional lens imaging instrument, and the cost is also lower. The imaging technology applied to mobile phones is also developing towards miniaturization and ultra-thinning, especially the development of full-screen and under-screen technologies on the front of mobile phones.

On the other hand, for the nature of LED itself, it not only has luminous properties, but also has photovoltaic sensing properties, so the light source on the screen surface can be directly obtained. By building a light sensing circuit, the light information on a single pixel can be obtained. Therefore, the pixels of the display screen can actually be used as light sensing elements or even as the basic unit of imaging. It is not realistic to use lensed imaging for the entire screen as an imaging sensor, but if combined with lensless imaging technology, direct imaging using LED large screens or future LED-based mobile phone displays can be achieved without the need for additional cameras. The method does not require additional imaging equipment, does not change the appearance and basic functions of the screen, has convenient application, simple structure and low cost, but no relevant reports have been reported so far.

SUMMARY OF THE INVENTION

In order to solve the problems in the background technology, the present invention provides a lensless imaging device and method for an LED display screen. The present invention utilizes the light sensing characteristics of the pixel unit LED of the LED display screen to directly obtain the light signal on the screen surface. The point spread function and light sensor image required for lensless imaging are formed, so that lensless imaging can be realized by calculating the restored image, and lensless imaging of objects by using LED display screen.

The technical scheme adopted by the present invention is as follows:

1. A lensless imaging device for an LED display screen.

Including objects, diffusers, LED display screens spliced by display unit boards, and image information recovery processing equipment, adjacent display unit boards are interconnected through a communication bus, and display unit boards are connected to image information recovery processing equipment through a communication bus. For communication; a diffuser is placed on the surface of the LED display screen and the diffuser is not in contact with the surface of the LED display screen, and objects are placed in front of the diffuser and the LED display screen;

The display unit board includes a driving and photoimaging circuit board and an LED dot matrix module. The LED dot matrix module is connected with the driving and photoimaging circuit boards through the circuit board and the dot matrix module connecting line group;

The driving and light imaging circuit board includes a microprocessor, a communication bus, a power supply module, a driving module and a screen light signal receiving module. The driving output of the driving module is connected to the LED dot matrix module for display driving, and the microprocessor is respectively connected with the driving module and the screen light signal receiving module. The screen light signal receiving module is connected, and the driving module is a driving circuit module including a tri-state gate. The output end of the tri-state gate and the screen light signal receiving module are connected with the LED dot matrix module through the circuit board and the dot matrix module connecting line group; The processor controls the drive module and the screen light signal receiving module through the three-state gate to realize the multiplexing of the display and light sensing functions of the LED dot matrix module. The communication function pins of the microprocessor are connected to the edge interface of the drive and the light imaging circuit board to form communication. bus; the power supply module provides power for the microprocessor, the driving module and the screen light signal receiving module by connecting with the external power supply.

The output end of the tri-state gate includes three states: high level, low level and high resistance. The high level and the low level correspond to the normal working state of the driving module, and the high resistance corresponds to the high resistance state of the driving module.

The LED dot matrix module is an N×M LED dot matrix arrangement structure, and each LED in the LED dot matrix module is a full-color three-primary color, dual-primary color or single color; the LED dot-matrix module includes a full-color three-primary color dot matrix module. , dual-color lattice module or single-color lattice module; full-color tri-color lattice module or dual-color lattice module includes N common anode VCC pins and K×L=M common cathode pins, N and M are A positive integer greater than or equal to 1; the single-color dot matrix module includes N common anode VCC pins and M common cathode pins, and N and M are positive integers greater than or equal to 1.

The display unit board has both a display function and a light sensing function; when the light sensing function is performed, the microprocessor controls the three-state gate to make the output port of the drive module in a high-impedance state, and the drive module is disconnected from the LED dot matrix module. Connection, the LED dot matrix module is only logically connected to the screen light signal receiving module, and the microprocessor obtains the light sensor image on the surface of the LED dot matrix module through the screen light signal receiving module; when performing the display function, the microprocessor controls the three The state gate keeps the output port of the drive module in a normal state, the LED dot matrix module performs the display function normally, and the screen light signal receiving module stops working at this time; the display function and the light sensing function are performed step by step in time to complete the independent light sensing. and display; or the display function and the light sensing function are switched at high speed to realize simultaneous light sensing and display based on the visual persistence effect. Each display unit board on the LED display screen can be in different functional states.

The photo sensor images of multiple LED dot matrix modules are spliced to form a complete photo sensor image received by the LED display screen, which is used as a photo sensor measurement value for lensless imaging. The photo sensor function does not need to introduce additional sensors, only when the LED display is retained. While the screen itself displays the function, the screen has a light sensing function.

The object actively emits light or is illuminated by a light source.

The image information restoration processing device is a computer or other microcomputer system that communicates and processes signals in real time.

The communication bus adopts the serial communication mode UART/I2C/SPI/RS232/USB, etc., which are commonly used by microprocessors, and is used to download the display signal and upload the photosensor images collected by each display unit board, and realize the restoration of image information. The communication between the processing device and the LED display screen and the interconnection communication between the display unit boards inside the LED display screen.

An appropriate distance should be maintained between the diffuser and the LED display screen, which is related to the focal length, and an appropriate object distance should also be maintained between the object and the diffuser. The diffuser is a transparent film, which does not affect the performance of the display function and the viewing effect.

The LED display screen is an infinitely extending matrix of X×Y unit panels formed by splicing display unit panels, where X and Y are positive integers greater than or equal to 1, or other shapes with interconnected properties formed by splicing display unit panels.

2. A lensless imaging method of an LED display screen according to the above device

Include the following steps:

Step 1): Calibration: first burn the corresponding execution program to the microprocessor through the communication bus, so as to have display and light sensing functions; then replace the object with a point light source and the position of the point light source is the same as that of the object before replacement The position is the same, and the LED display screen is switched to the light sensing function at the same time. The scattered light from the point light source to the surface of the display unit panel through the diffuser produces a photovoltaic effect in the LED to generate a light signal. The light signal of each LED is collected to obtain a local light sensor image, and then the information of multiple LED dot matrix modules is aggregated to the image information recovery processing equipment through the communication bus, and the complete light sensor image is obtained through integration;

Then, by adjusting the distance between the point light source or the diffuser and the LED display screen, the image information recovery processing equipment can obtain a clear light sensor image, thereby completing the calibration. The calibration process is called point spread function measurement. The clear light corresponding to the point light source The sensor image is a point spread function (PSF) for lensless imaging;

Step 2): Shooting and Displaying: The photo-sensing process during shooting and the display process of the LED display screen are carried out step by step in time to realize the independent execution of the display function; or by switching the display function and photo-sensing of the display unit board at a high speed function, so that the display process and the light sensing process in shooting are performed at the same time;

The shooting process is specifically as follows: placing the object at the position of the point light source calibrated in step 1), the microprocessor makes the output end of the drive module in a high resistance state through the tri-state gate, and the display unit board is in the light sensing function. State, also use the light signal generated by the photovoltaic effect of the LED to obtain the light sensor image corresponding to the surface of the LED dot matrix module, and then gather the information of multiple LED dot matrix modules to the image information recovery processing equipment through the communication bus. , that is, to obtain a photosensor image for lensless imaging;

The display process is specifically as follows: when the microprocessor makes the output end of the drive module in a normal state through the tri-state gate, the display unit board is in a display function state, and the LED display screen realizes the display of images;

Step 3): Reconstructing the image: input the point spread function obtained in step 1) and the photosensor image obtained in step 2) into the image information restoration processing device, and the image information restoration processing device executes the photosensor image in step 2) according to the point spread function. The image reconstruction algorithm of lensless imaging can restore the image of the object and realize the imaging process of the object.

The image reconstruction algorithm for lensless imaging includes alternating direction multiplier method ADMM or improved methods based on ADMM, such as Le-ADMM, Le-ADMM*, Le-ADMM-U, etc. and other lensless imaging methods.

The light signal is an analog photovoltage signal generated by the photovoltaic effect, and represents light intensity information within a certain frequency range.

For LED dot matrix modules using single-color LEDs or without considering LED color sensing, the imaging result of the object is a black and white grayscale image; for LED dot matrix modules using full-color three-primary LEDs, three different light intensities can be obtained. The information can further realize the detection of the light intensity of the three color channels of RGB, and the imaging result of the object is a color image.

The beneficial effects of the present invention are:

1) Because the present invention utilizes the sensing characteristics of display pixels, no additional sensors or cameras are required, which is equivalent to directly reducing an access device, turning the LED display screen into a device with both display and imaging functions. While reducing the cost, it can also realize the direct and convenient use of the LED display screen to complete the imaging, which expands the function of the screen.

2) In the present invention, only a layer of transparent diffuser film is added to the appearance, and only the driving circuit of the LED dot matrix screen itself is modified, and the appearance and display method are not changed, so it hardly affects the display of the LED display screen. effect and use, so it can be applied to a variety of occasions that require display and imaging, with a wide range of applications.

3) The present invention can be used in conjunction with other unit boards with only display functions to obtain a display screen with integrated display and imaging, thereby realizing a new interactive experience.

Description of drawings

FIG. 1 is a frame diagram of a method for realizing lensless imaging according to the present invention.

FIG. 2 is a schematic diagram of the overall structure of the device of the present invention.

FIG. 3 is a schematic structural diagram of a display unit board.

Figure 4 is a diagram of the internal structure of the drive and photoimaging circuit board.

Figure 5 is a structural diagram of an LED dot matrix screen.

FIG. 6 is a flow chart of lensless imaging according to the present invention.

In the picture: 1. Object, 2. Diffuser, 3. Display unit board, 4. LED display screen, 5. Image information recovery processing device, 6. Communication bus, 7. Drive and photoimaging circuit board, 8. LED point Array module, 9. Pixel, 10. Microprocessor, 11. Power supply module, 12. Drive module, 13. Screen light signal receiving module, 14. Circuit board and dot matrix module connecting line group, 15. Tri-state gate.

Detailed ways

The present invention will be further described below with reference to specific embodiments.

As shown in FIG. 1 and FIG. 2, the method of the present invention is to place a layer of diffuser 2 on the front of the LED display screen 4, and the object 1 that is actively emitting light or illuminated by the light source will emit the reflected light or self-illumination of the object, This light irradiates on the diffuser to form scattering, but does not cause reflection. After the light is scattered, it passes through the diffuser and irradiates on the LED display screen 4. At the same time, the LED pixel unit LED on the LED display screen 4 increases the photoelectricity in addition to the light-emitting function. The sensing function and the corresponding receiving circuit, in the photoelectric sensing receiving state, can generate light signals on the LED pixels, and each display unit board 3 of the LED display screen 4 collects the local image on its own unit board, and then passes The communication bus 6 transmits to the image information restoration processing device 5 to collect the image of the entire screen, and to restore the image through the imaging calculation, the imaging of the object can be realized. The LED display 4 can continue to perform the display function while performing the imaging function.

As shown in FIG. 2 , the present invention includes an LED display screen 4 formed by splicing an object 1, a diffuser 2, and a display unit board 3, and an image information recovery processing device 5, and the adjacent display unit boards 2 are interconnected through a communication bus 6, And it is connected to the external or internal image information recovery processing device 5 through the communication bus 6 for communication; the diffuser 2 is placed on the surface of the LED display screen 4, and the object 1 is placed in front of the diffuser 2 and the LED display screen 4 and maintained. a certain distance.

In the specific implementation, the distance between the object 1 and the diffuser 2 is determined according to the point light source distance during calibration, and the distance between the diffuser 2 and the LED display screen 4 is determined by the point spread function image with the best effect and the clearest obtained during calibration.

As shown in FIG. 3 , the display unit board 2 of the present invention includes a driving and photoimaging circuit board 7 and an LED dot matrix module 8 . The LED dot matrix module 8 is directly connected to the driving and photoimaging circuit board 7 through the circuit board and the dot matrix module connecting line group 14 .

As shown in FIG. 4 , the driving and photoimaging circuit board 7 of the present invention includes a microprocessor 10 , a communication bus 6 , a power supply module 11 , a driving module 12 and a screen light signal receiving module 13 . The driving output of the driving module 12 is directly connected to the LED dot matrix module 8 for display driving. The microprocessor 10 is respectively connected with the driving module 12 and the screen light signal receiving module 13 . The driving module 12 is a driving circuit module with a tri-state gate 15 , and the microprocessor 10 controls the driving module 12 and the screen light signal receiving module 13 through the tri-state gate 15 to realize the multiplexing of the display and light sensing functions of the LED pixels 9 . The communication function pins of the microprocessor 10 are connected to the edge interface of the driving and photoimaging circuit board 7 to form a communication bus 6; .

In the specific implementation, the microprocessor 10 in the display unit board 3 adopts an ATmega2560 chip with an 8-bit microcontroller with 16 analog input ports, and the main chip of the drive module 12 includes an eight-way positive-phase three-state driver 74ACT244 with the function of a three-state gate 15 , A dedicated 8×8 full-color RGB-LED dot matrix screen driver chip DM163, the main chip of the screen light signal receiving module 13 is four operational amplifiers LM324, and the voltage of the power supply module 11 is 5V.

In a specific implementation, as shown in FIG. 5 , the LED dot matrix module 8 used in the present invention is an 8×8 full-color LED dot matrix arrangement structure. For each pixel 9, each pair of three-primary-color LEDs are integrated in the same chip, the model of the dot matrix screen used is GTM2088ARGB, and the model of each three-primary-color LED is SMD 5050RGB.

In the specific embodiment, a 4*4 LED display screen 4 is formed by 16 display unit boards 3, the communication between the display unit boards 3 is realized by I2C, and the communication mode between the LED display screen 4 and the image information recovery processing device 5 UART for Universal Asynchronous Receiver Transmitter.

In specific implementation, the image information restoration processing device 5 uses a general-purpose computer.

The working principle of the present invention is as follows:

The first is to obtain the initial sensor image on the LED display screen 4: when each display unit board 3 in the LED display screen 4 is ready for use, it will be connected to the computer through the communication bus 6 to program the program. The function of the program includes two parts: On the one hand, it is the display function. The program uses the traditional dynamic scanning display method to drive one row of LEDs to realize the display function at each display moment. After fast switching, after driving all the rows to display once, the display of one frame can be completed. The scanning speed is more than 30 frames. Using the visual persistence effect of the human eye, the normal display of one frame can be realized. When the anode voltage is lower than the cathode voltage, it has a photoelectric effect and can detect the light intensity information of the external light source to the LED. In implementation, after the influence of the driving module 12 is isolated by the tri-state function 15 , the light intensity on each pixel 9 of the LED display screen 4 can be detected by the screen light signal receiving module 13 . After sampling and integration by the microprocessor 10 , the local image information on the LED dot matrix module of each display unit board 3 can be obtained in each display unit board 3 . After the transmission through the communication bus 6 , the photo sensor image of the entire LED display screen 4 can be obtained in the image information restoration processing device 5 . Therefore, this process is equivalent to completing the process of collecting images such as the light sensor array in the camera.

The second is the imaging principle of lensless imaging:

Since no lens is used, the photosensor image captured in the LED display screen 4 is not the image of the object 1 or the scene, but an initial blurred image, which is referred to as a photosensor image here. In order to recover the actual image of the object 1 or the scene from the photosensor image, a lensless imaging algorithm needs to be performed to calculate the image of the object 1 or the scene.

Replacing Object 1 or the scene with a single point light source produces a high-contrast corrosive pattern on the light sensor, which is the point spread function (PSF) of the system: h. If the scene is modeled as a collection of point sources with different colors and intensities, and assuming that all points are incoherent, the light sensor image b of the scene is described as:

b(x, y)=crop[h(x, y)*x(x, y)]=CHx ①

The image of the object 1 or the scene is x, (x, y) is the coordinates in the light sensor, and C, H, and x are the abbreviations for crop[], h(x, y), and x(x, y), respectively. The crop operation crop[] limits the output to the physical sensor size. Our goal is to recover scene x from measurement b.

With the point spread function PSF known, the restoration of object 1 or scene can be written as:

即可得到物体1即场景的图像，实现无透镜成像。where Ψ is the sparsity transformation and τ is the tuning parameter to adjust the sparsity. by calculating

The image of the object 1, that is, the scene can be obtained, and lensless imaging can be realized.

The implementation process of the present invention is as follows (as shown in Figure 6):

Step 1): Calibration. First, program the corresponding execution program to the microprocessor 10 through the communication bus 6, so that the display unit board 3 has the functions of display and light detection; The white LED of the LED display screen 4 only works in the light sensing function at this time, and the light intensity irradiated on each pixel on the LED display screen 4 will be sensed and collected. mode, the sensitivity of the collected optical signal is 20mV/lum. After the display unit board 3 collects a partial image on its own screen, it is transmitted to a selected host unit board through I2C, and then the host unit board transmits it to the image information recovery processing device 5 through UART, and the computer can obtain the entire LED display screen. , the image pixel size of this image is 32*32. At this point, the image is the point spread function (PSF) h(x, y) for lensless imaging.

Step 2): Take a photosensor image of the object. The object 1 to be imaged is placed at the point light source position in step 1). Then, in the specific implementation, the LED display screen 4 still only works under the light sensing function, and the microprocessor 10 sends an enable signal to control the drive module. The three-state enable switch of 74ACT244 in 12 is turned on, and the connection between the driver module 12 and the LED dot matrix module 8 is disconnected, and the LM324 in the screen light signal receiving module 13 receives the light sensor on the LED dot matrix module 8. After the information is amplified and filtered, it is sent to the microprocessor 10 for sampling, which is the same as step 1). Finally, the image on the entire LED display screen is obtained and transmitted to the image information recovery processing device 5 through the communication bus UART. At this time The acquired image is the photosensor image b(x, y) for lensless imaging.

Step 3): Reconstruct the image. At this time, the point spread function h(x, y) when the point light source is irradiated and the photosensor image b when the object 1 is placed have been acquired in steps 1) and 2) in the image information restoration processing device 5. (x, y), these pieces of information are all stored in the image information restoration processing device 5 .

The image information recovery processing device (5) performs an image reconstruction algorithm of lensless imaging on the photosensor image in step 2) according to the point spread function, thereby recovering the image of the object and realizing the imaging process of the object (1). The specific process is as follows:

With the known point spread function PSF, the recovery of object 1 can be written as:

where Ψ is the sparse transformation, τ is the adjustment parameter for adjusting the sparsity; x' is the image of object 1 obtained in the last iteration, x' in the initial iteration process is the light sensor image b; C, H, x' are crop, respectively Abbreviations for [], h(x, y), x'(x, y), (x, y) are coordinates in LED display screen 4, crop operation crop[] limits the output to the size of LED display screen 4 .

即为物体1最终的恢复图像，实现无透镜成像，具体操作如下：Calculated by iterative optimization algorithm

That is, the final restored image of object 1 to achieve lensless imaging. The specific operations are as follows:

Further transformation according to formula ② can be obtained:

stv=Hx', u=Ψx', w= _x ' ③

Then the final restored image of object 1 is obtained through an iterative optimization algorithm

x ^k+1 ←(μ ₁ H ^T H+μ ₂ Ψ ^T Ψ+μ ₃ I) ^-1 r ^k

α₁，α₂，α₃是拉格朗日乘子，代表u，v，w的对偶变量；μ₁，μ₂，μ₃是惩罚参数；

是参数τ/μ₂的矢量阈值；x^k、x^k+1与x’含义相同，均表示上一次的迭代结果，k为当前的迭代次数；。in,

α ₁ , α ₂ , α ₃ are Lagrange multipliers, representing the dual variables of u, v, w; μ ₁ , μ ₂ , μ ₃ are penalty parameters;

is the vector threshold of the parameter τ/μ ₂ ; x ^k , x ^k+1 have the same meaning as x', both represent the result of the previous iteration, and k is the current iteration number;

In a specific embodiment, only a single primary color LED in the full-color LEDs, that is, a red LED is used as a sensor, so the imaging of a black and white image is finally realized.

Claims (9)

1. A lensless imaging device for an LED display screen, characterized in that it comprises an object (1), a diffuser (2), an LED display screen (4) formed by splicing a display unit board (3), and image information Recovery processing equipment (5), adjacent display unit boards (2) are interconnected through a communication bus (6), and the display unit boards (2) are connected to the image information recovery processing equipment (5) for communication through the communication bus (6); A diffuser (2) is placed on the surface of the LED display screen (4) and the diffuser (2) is not in contact with the surface of the LED display screen (4). Objects are placed in front of the diffuser (2) and the LED display screen (4). (1); The display unit board (2) includes a driving and photoimaging circuit board (7) and an LED dot matrix module (8). The LED dot matrix module (8) is connected with the driving and photoimaging circuit board (7) through the circuit board and the dot matrix module connecting line group (14); The driving and light imaging circuit board (7) comprises a microprocessor (10), a communication bus (6), a power supply module (11), a driving module (12) and a screen light signal receiving module (13), and the driving module (12) The driving output of the LED dot matrix module (8) is connected to the LED dot matrix module (8) for display driving, the microprocessor (10) is respectively connected with the driving module (12) and the screen light signal receiving module (13), and the driving module (12) is composed of a three-state gate In the drive circuit module of (15), the output end of the tri-state gate (15) and the screen light signal receiving module (13) are connected to the LED dot matrix module (8) through the circuit board and the dot matrix module connecting line group (14); The microprocessor (10) controls the driving module (12) and the screen light signal receiving module (13) through the tri-state gate (15) to realize the multiplexing of the display of the LED dot matrix module (8) and the light sensing function, and the microprocessor ( The communication function pin of 10) is connected to the edge interface of the driving and photoimaging circuit board (7) to form a communication bus (6); The signal receiving module (13) provides power. 2. The lensless imaging device of an LED display screen according to claim 1, wherein the output end of the three-state gate (15) comprises three states: high level, low level and high resistance, and the high level The level and the low level correspond to the normal working state of the driving module (12), and the high resistance corresponds to the high resistance state of the driving module (12). 3. The lensless imaging device of an LED display screen according to claim 1, wherein the LED dot matrix module (8) is an N×M LED dot matrix arrangement structure, and the LED dot matrix module (8) ) for each LED in full color tri-color, dual-primary or single color. 4. The lensless imaging device of an LED display screen according to claim 1, characterized in that: the display unit board (3) has both a display function and a light sensing function; The processor (10) keeps the output port of the driving module (12) in a high-impedance state by controlling the tri-state gate (15), the driving module (12) is disconnected from the LED dot matrix module (8), and the LED dot matrix module (8) ) is only logically connected to the screen light signal receiving module (13), and the microprocessor (10) obtains the light sensor image on the surface of the LED dot matrix module (8) through the screen light signal receiving module (13); when performing the display function , the microprocessor (10) makes the output port of the drive module (12) in a normal state by controlling the tri-state gate (15), and the LED dot matrix module (8) normally performs the display function; the display function and the light sensing function are separated in time. Step by step to complete independent light sensing and display; or display function and light sensing function are switched at high speed to realize simultaneous light sensing and display based on visual persistence effect. 5. A lensless imaging device for an LED display screen according to claim 4, characterized in that: the complete light received by the LED display screen (4) is formed after the photosensor images of the plurality of LED dot matrix modules (8) are spliced together. sensor image. 6 . The lensless imaging device for an LED display screen according to claim 1 , wherein the object ( 1 ) actively emits light or is illuminated by a light source. 7 . 7. A lensless imaging method for an LED display screen according to any one of the device described in claims 1-6, characterized in that, comprising the following steps: Step 1): Calibration: replace the object (1) with a point light source and the position of the point light source is the same as the position of the object (1) before the replacement, and switch the LED display screen (4) to the light sensing function, The scattered light irradiated by the point light source to the surface of the display unit panel (3) through the diffuser (2) produces a photovoltaic effect in the LED to generate an optical signal. The signal is collected to obtain a local photosensor image, and then the information of the plurality of LED dot matrix modules (8) is aggregated to the image information recovery processing device (5) through the communication bus (6), and a complete photosensor image is obtained through integration; Then, by adjusting the distance between the point light source or the diffuser (2) and the LED display screen (4), the image information recovery processing device (5) obtains a clear photosensor image, thereby completing the calibration. The calibration process is called point diffusion. Function measurement, the clear light sensor image corresponding to the point light source is the point spread function for lensless imaging; Step 2): Shooting and Displaying: The photo-sensing process during shooting and the display process of the LED display screen (4) are carried out step-by-step in time to realize the independent execution of the display function; or by switching the display unit board (2) at a high speed The display function and light-sensing function of the camera enable the display process and the light-sensing process in shooting to be performed simultaneously; The shooting process is specifically as follows: placing the object (1) at the position of the point light source calibrated in step 1), and the microprocessor (10) causes the output end of the driving module (12) to be in the position of the three-state gate (15) through the tri-state gate (15). In the high resistance state, the display unit board (2) is in the light sensing function state, and the light signal generated by the photovoltaic effect of the LED is also used to obtain the light sensor image corresponding to the surface of the LED dot matrix module (8), and then the light sensor image is obtained through the communication bus (6) After the information of the plurality of LED dot matrix modules (8) is gathered into the image information restoration processing device (5), a complete photosensor image is obtained through integration, that is, a photosensor image for lensless imaging is obtained; The display process is specifically as follows: when the microprocessor (10) makes the output end of the drive module (12) in a normal state through the tri-state gate (15), the display unit board (3) is in a display function state, and the LED display screen (4) ) to realize the display of the image; Step 3): reconstructing the image: the point spread function obtained in step 1) and the photosensor image obtained in step 2) are input into the image information restoration processing device (5), and the image information restoration processing device (5) performs step 2 according to the point spread function. ) of the photosensor image to execute the image reconstruction algorithm of lensless imaging, thereby recovering the image of the object and realizing the imaging process of the object (1). 8. The lensless imaging method of an LED display screen according to claim 7, wherein the image reconstruction algorithm of the lensless imaging comprises an alternating direction multiplier method ADMM or an improved method based on ADMM, such as Le - ADMM, Le-ADMM*, Le-ADMM-U. 9. The lensless imaging method of an LED display screen according to claim 7, characterized in that, for the LED dot matrix module (8) using a single-color LED, the imaging result of the object (1) is a black and white grayscale image ; For the LED dot matrix module (8) using full-color three-primary LEDs, the imaging result of the object (1) is a color image.

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