Parameter calibration method and device of projection system, electronic equipment and storage medium

Abstract

The invention discloses a parameter calibration method and device of a projection system, electronic equipment and a storage medium, and relates to the technical field of projection. The method comprises the following steps: projecting a white field image and a black field image to a target area through a target projector, and carrying out image shooting on the target area through a plurality of cameras to obtain a plurality of first images and a plurality of second images; acquiring a plurality of brightness distribution conditions of projection picture areas in the plurality of first images; and if the target brightness distribution condition does not meet the preset brightness distribution condition, performing iterative adjustment on the display brightness parameter of the target projector and / or the camera parameter of the camera until the re-acquired target brightness distribution condition meets the preset brightness distribution condition after the display brightness parameter and / or the camera parameter are / is adjusted. And obtaining a calibrated display brightness parameter of the target projector and a calibrated camera parameter of the camera. Therefore, the projector picture image shot by the camera can automatically adapt to the change of ambient light, and the brightness consistency is kept.

Description

Technical Field

[0001] The present application relates to the field of projection technology, and in particular to a parameter calibration method, device, electronic device and storage medium for a projection system. Background Art

[0002] In the related art, a projector projects a fringe pattern to assist in realizing functions such as projector focus, geometric correction or 3D reconstruction. However, if the brightness of the image projected by the projector is not appropriate, for example, if it is too dark, the projected fringe will not be clear, while if it is too bright, the overexposed fringe will be indecipherable. Therefore, how to effectively perform environmental adaptive adjustment on the projection brightness parameters of the projection system has become an urgent problem to be solved. Summary of the invention

[0003] The present application proposes a method, device, electronic device and storage medium for calibrating parameters of a projection system to adaptively adjust the projection brightness parameters of the projection system.

[0004] In a first aspect, an embodiment of the present application provides a method for calibrating parameters of a projection system, wherein the projection system includes multiple projectors and multiple cameras, and the method includes: projecting a white field image to a target area through a target projector, and capturing images of the target area through the multiple cameras to obtain multiple first images, and projecting a black field image to the target area through the target projector, and capturing images of the target area through the multiple cameras to obtain multiple second images, wherein the multiple second images correspond one-to-one to the multiple first images, and the target projector is any one of the multiple projectors; obtaining a difference image between each of the first images and its corresponding second image, and determining, based on the difference image, a projection screen area formed by the projection of the target projector in each of the first images as the projection screen area of ​​each of the first images. a first projection picture area; according to the grayscale value of each pixel point in the first projection picture area of ​​each first image, obtaining the brightness distribution of each first image, and obtaining a plurality of brightness distributions, wherein the plurality of brightness distributions correspond to the plurality of cameras one by one; if the target brightness distribution does not meet the preset brightness distribution conditions, iteratively adjusting the display brightness parameters of the target projector and / or the camera parameters of the target camera until the re-acquired target brightness distribution meets the preset brightness distribution conditions after adjusting the display brightness parameters and / or the camera parameters, obtaining the adjusted display brightness parameters as the calibrated display brightness parameters of the target projector, and obtaining the adjusted camera parameters as the calibrated camera parameters of the target camera, wherein the target brightness distribution is obtained based on the plurality of brightness distribution conditions.

[0005] In a second aspect, an embodiment of the present application provides a parameter calibration device for a projection system, wherein the projection system includes a plurality of projectors and a plurality of cameras, and the device includes: an image acquisition module, a projection area determination module, a brightness distribution acquisition module, and a parameter calibration module. The image acquisition module is used to project a white field image to a target area through a target projector, and to capture images of the target area through the plurality of cameras to obtain a plurality of first images, and to project a black field image to the target area through the target projector, and to capture images of the target area through the plurality of cameras to obtain a plurality of second images, wherein the plurality of second images correspond one-to-one to the plurality of first images, and the target projector is any one of the plurality of projectors; the projection area determination module is used to acquire a difference image between each of the first images and its corresponding second image, and based on the difference image, determine a projection screen area formed by the projection of the target projector in each of the first images as the first projection screen area of ​​each of the first images; the brightness distribution acquisition module is used to determine a projection screen area formed by the projection of the target projector in each of the first images according to each of the first images; The method comprises the following steps: obtaining a grayscale value of each pixel in a first projection screen area of ​​an image, obtaining a brightness distribution of each of the first images, and obtaining a plurality of brightness distributions, wherein the plurality of brightness distributions correspond to the plurality of cameras one by one; and a parameter calibration module, which is used for iteratively adjusting the display brightness parameters of the target projector and / or the camera parameters of the target camera if the target brightness distribution does not meet the preset brightness distribution conditions, until the target brightness distribution reacquired after adjusting the display brightness parameters and / or the camera parameters meets the preset brightness distribution conditions, obtaining the adjusted display brightness parameters as the calibrated display brightness parameters of the target projector, and obtaining the adjusted camera parameters as the calibrated camera parameters of the target camera, wherein the target brightness distribution is obtained based on the plurality of brightness distribution conditions.

[0006] In a third aspect, an embodiment of the present application provides an electronic device, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs are configured to execute the above-mentioned method.

[0007] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, in which a program code is stored. The program code can be called by a processor to execute the above method.

[0008] In the solution provided by the present application, a target projector projects a white field image onto a target area, and a plurality of cameras are used to capture images of the target area to obtain a plurality of first images, and a target projector projects a black field image onto the target area, and a plurality of cameras are used to capture images of the target area to obtain a plurality of second images, wherein the plurality of second images correspond to the plurality of first images one by one, and the target projector is any one of the plurality of projectors; a difference image between each first image and its corresponding second image is obtained, and based on the difference image, a projection screen area formed by the projection of the target projector in each first image is determined as a first projection screen area of ​​each first image; and according to the first projection screen area of ​​each first image, a projection screen area is formed by the projection of the target projector. The grayscale value of each pixel point in the surface area is obtained, and the brightness distribution of each first image is obtained to obtain multiple brightness distribution conditions, and the multiple brightness distribution conditions correspond to multiple cameras one by one; if the target brightness distribution condition does not meet the preset brightness distribution condition, the display brightness parameter of the target projector and / or the camera parameter of the target camera are iteratively adjusted until the display brightness parameter and / or the camera parameter are adjusted, and the re-acquired target brightness distribution condition meets the preset brightness distribution condition, and the adjusted display brightness parameter is obtained as the calibrated display brightness parameter of the target projector, and the adjusted camera parameter is obtained as the calibrated camera parameter of the target camera, and the target brightness distribution condition is obtained based on the multiple brightness distribution conditions. In this way, by iteratively adjusting the display brightness parameter and / or camera parameter combination of the projector, the multi-camera multi-projection projection system can automatically and quickly adjust to reasonable parameters to ensure that under the combination of each projector and each camera, the image projected and displayed by the projector can be in a reasonable brightness range to prevent the occurrence of too dark or overexposure; at the same time, it also ensures that each camera can capture an image whose brightness distribution meets the preset brightness distribution condition, thereby ensuring the normal use of the projector focus, geometric correction and three-dimensional reconstruction functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 A schematic flow chart of a method for calibrating parameters of a projection system provided in an embodiment of the present application is shown.

[0011] Figure 2 A system schematic diagram of a projection system provided in an embodiment of the present application is shown.

[0012] Figure 3A schematic diagram of a first image provided in an embodiment of the present application is shown.

[0013] Figure 4 A schematic diagram of a second image provided in an embodiment of the present application is shown.

[0014] Figure 5 Shows Figure 1 A schematic flow chart of the sub-steps of step S120 in one implementation manner.

[0015] Figure 6 A schematic diagram of a binarized image provided in an embodiment of the present application is shown.

[0016] Figure 7 A schematic flow chart of a method for calibrating parameters of a projection system provided in another embodiment of the present application is shown.

[0017] Figure 8 A schematic diagram of the steps of parameter calibration of a projection system provided in an embodiment of the present application is shown.

[0018] Fig. 9 It is a block diagram of a parameter calibration device for a projection system provided according to an embodiment of the present application.

[0019] Fig.10 It is a block diagram of an electronic device for executing a parameter calibration method of a projection system according to an embodiment of the present application.

[0020] Fig.11 It is a storage unit of the embodiment of the present application for storing or carrying a program code for implementing the parameter calibration method of the projection system according to the embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] It should be noted that in some processes described in the specification, claims and the above-mentioned drawings of the present application, multiple operations that appear in a specific order are included, and these operations may not be executed or executed in parallel in the order in which they appear in this article. The sequence numbers of operations such as S110, S120, etc. are only used to distinguish different operations, and the sequence numbers themselves do not represent any execution order. In addition, these processes may include more or less operations, and these operations may be executed in sequence or in parallel. And, the terms "first", "second", etc. in the specification, claims and the above-mentioned drawings of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or server that includes a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules that are not explicitly listed or that are inherent to these processes, methods, products, or devices.

[0023] In the related art, the fringe pattern displayed by the projector has many uses: projector focus, geometric correction, three-dimensional reconstruction, etc. However, if the brightness of the projector is not appropriate, too dark will cause the projected stripes to be unclear, and too bright will cause the overexposed stripes to be unable to be resolved. Therefore, it is particularly important to calibrate the brightness of the projector and adaptively adjust the environment. For the decoding process of stripe structured light, the pixel grayscale value is very important, which affects the precision and accuracy of the three-dimensional reconstruction results. In order to minimize the loss of image acquisition information due to inconsistent camera brightness, it is also necessary to adaptively adjust the brightness of different cameras.

[0024] Factors such as inconsistent projector display brightness, projection distance, projection method, camera shooting distance, etc. will result in different cameras needing different parameter combinations to ensure the consistency of image brightness when shooting images projected by different projectors, making the brightness calibration and adaptive adjustment system of the multi-camera and multi-projector system more complicated and requiring a set of feasible methods to solve.

[0025] To solve the above problems, the inventor proposes a method, device, electronic device and storage medium for calibrating parameters of a projection system. The following is a detailed description of the method for calibrating parameters of a projection system provided in an embodiment of the present application.

[0026] Please refer to Figure 1 , Figure 1 A flow chart of a method for calibrating parameters of a projection system provided in one embodiment of the present application. Figure 1The parameter calibration method of the projection system provided in the embodiment of the present application is described in detail. The parameter calibration method of the projection system may include the following steps:

[0027] Step S110: projecting a white field image to a target area through a target projector, and capturing images of the target area through the multiple cameras to obtain multiple first images, and projecting a black field image to the target area through the target projector, and capturing images of the target area through the multiple cameras to obtain multiple second images, wherein the multiple second images correspond one-to-one to the multiple first images, and the target projector is any one of the multiple projectors.

[0028] In this embodiment, the projection system includes multiple projectors and multiple cameras, such as Figure 2 As shown, the projection system 20 may include a projector 211, a projector 212, a projector 213, a camera 221, a camera 222, a camera 223, and a camera 224. Of course, in practical applications, the number of projectors and cameras included in the projection system may be more or less, and this embodiment does not limit this. Among them, the camera may be a black and white camera or a color camera, such as an RGB camera. It should be noted that the shooting range of any camera in the multiple cameras can cover the projection range of any projector in the multiple projectors.

[0029] Since the projection system includes multiple projectors, the brightness parameters of each projector can be calibrated in turn, and the corresponding camera parameters of the combination of each projector and each camera can be calibrated, so that in the subsequent applications of the projection system (such as projector focus, geometric correction or three-dimensional reconstruction), the fringe pattern projected and displayed by each projector can be within a reasonable brightness range, and the brightness distribution of the image captured by each camera is also similar, so as to ensure the accuracy of subsequent applications. Specifically, a white field image can be projected onto the target area by a target projector (i.e., any one of the multiple projectors), and the target area can be captured by multiple cameras to obtain multiple first images, and the multiple first images correspond one-to-one to the multiple cameras; wherein the white field image can be understood as a pure white image. Furthermore, a black field image can be projected onto the target area by a target projector, and the target area can be captured by multiple cameras to obtain multiple second images, and the multiple second images correspond one-to-one to the multiple cameras; wherein the black field image can be understood as a pure black image. Exemplarily, the target projector projects a white field image onto the target area where a bear model is placed, and the first image captured by the camera can be as follows Figure 3 As shown; and, the target projector projects a black field image onto the target area where the bear model is placed, and the second image captured by the camera can be as shown Figure 4 shown.

[0030] by Figure 2 Taking the projection system 20 shown as an example, the projector 211 is used as the current target projector to be calibrated for brightness parameters. Then, a white field image is projected onto the target area by projector 211, and the target area is imaged by cameras 221, 222, 223, and 224, respectively, to obtain four first images; a black field image is projected onto the target area by projector 211, and the target area is imaged by cameras 221, 222, 223, and 224, respectively, to obtain four second images. Obviously, the four first images correspond to the four second images one by one, that is, the first image captured by camera 221 corresponds to the second image captured by camera 221. Similarly, if projector 212 or projector 213 is used as the current target projector to be calibrated for brightness parameters, it is calibrated in the same way, and examples are not repeated here.

[0031] Step S120: Obtain a difference image between each of the first images and its corresponding second image, and based on the difference image, determine a projection screen area formed by the target projector in each of the first images as a first projection screen area of ​​each of the first images.

[0032] Optionally, if the camera is a color camera, a first grayscale image corresponding to each first image is obtained, and a second grayscale image corresponding to each second image corresponding to the first image is obtained, and a difference image between the first grayscale image and the second grayscale image is obtained. The difference image can be used to reflect the pixel point area with significant differences between the first image and the corresponding second image.

[0033] Optionally, if the camera is a black and white camera, the first image and the second image captured are both grayscale images, so the difference image between each first image and its corresponding second image can be directly obtained.

[0034] It should be noted that the execution subject of this application is an electronic device with data processing capability in the projection system 10 (not in Figure 2 As shown in the figure, the electronic device establishes a wired or wireless communication connection with each camera and each projector, so that data and control signals can be transmitted based on the communication connection.

[0035] In some embodiments, see Figure 5 , step S120 may specifically include the following steps S121 to S123:

[0036] Step S121: binarizing the difference image to obtain a binarized image corresponding to the difference image.

[0037] Among them, the binarization process can be understood as setting a gray value threshold, mapping the gray value of pixels greater than or equal to the gray value threshold to 255, that is, processing the pixels greater than or equal to the gray value threshold as white; and mapping the gray value of pixels less than the gray value threshold to 0, that is, processing the pixels less than the gray value threshold as black. In other words, through the binarization process, the difference image of the gray image is converted into a black and white image, that is, the binarized image corresponding to the obtained difference image is a gray-white image. The binarized image can also be understood as a mask image that excludes ambient light. Figure 3 is the first image, Figure 4 For the second image, Figure 3 and Figure 4 The difference image is binarized, and the obtained binary image can be Figure 6 shown.

[0038] Step S122: Obtaining the region position of the white region in the binary image.

[0039] Step S123: determining an image region corresponding to the region position of the white region from each of the first images as a first projection image region of each of the first images.

[0040] In the binary image, the pixel area mapped as the white area is the pixel area with significant difference between the first image and the second image. Therefore, the area position of the white area composed of white pixels can be obtained according to the pixel position of all white pixels in the binary image; this white area can be understood as the projection display area formed by the projection of multiple first projectors captured by the camera. Therefore, the image area corresponding to the area position of the white area can be determined from the first image as the projection display area formed by the projection of multiple first projectors.

[0041] by Figure 2 Taking the projection system 20 shown as an example, projector 211 is used as the current target projector to be calibrated for brightness parameters; ultimately, the projection image area in the first image taken by camera 221, the projection image area in the first image taken by camera 222, the projection image area in the first image taken by camera 223, and the projection image area in the first image taken by camera 224 are determined.

[0042] Step S130: acquiring the brightness distribution of each first image according to the grayscale value of each pixel in the first projection picture area of ​​each first image, and obtaining a plurality of brightness distributions, wherein the plurality of brightness distributions correspond one-to-one to the plurality of cameras.

[0043] Specifically, according to the grayscale value of each pixel in the first projection screen area of ​​each first image, the grayscale histogram of each first image is obtained as the brightness distribution of each first image. Further, the target brightness distribution can be determined based on the multiple brightness distributions. Specifically, the average grayscale value of the grayscale values ​​of the preset quantiles in the brightness distribution of all first images can be obtained as the target brightness distribution; the target brightness distribution can also be understood as the average brightness distribution of the images collected by multiple cameras when the target projector is currently projecting an image. The grayscale value of the preset quantile can be used to feedback the central trend and discreteness of the grayscale value of each pixel in the first projection screen area. The preset quantile is a pre-set value, for example, 0.90 or 0.95.

[0044] Optionally, if the average grayscale value is not within the preset grayscale value range, it is determined that the target brightness distribution does not meet the preset brightness distribution condition; if the average grayscale value is within the preset grayscale value range, it is determined that the target brightness distribution meets the preset brightness distribution condition.

[0045] Step S140: If the target brightness distribution does not meet the preset brightness distribution conditions, the display brightness parameters of the target projector and / or the camera parameters of the camera are iteratively adjusted until the target brightness distribution obtained after adjusting the display brightness parameters and / or the camera parameters meets the preset brightness distribution conditions, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the adjusted camera parameters are obtained as the calibrated camera parameters of the camera, and the target brightness distribution is obtained based on the multiple brightness distribution conditions.

[0046] Among them, the display brightness parameter is a luminous flux parameter; the camera parameters include at least one of the parameters such as exposure time, gain and aperture. The brightness of the display screen projected by the projector is positively correlated with the luminous flux parameter, that is, the larger the luminous flux parameter, the higher the brightness of the display screen projected by the corresponding projector. Exposure time refers to the time interval from the opening to the closing of the camera shutter, during which the object can leave an image on the film; the longer the exposure time, the more light, that is, the longer the exposure time, the higher the brightness of the image captured by the camera, that is, the brightness of the image captured by the camera is also positively correlated with the exposure time. The gain of the camera mainly refers to changing the sensitivity of the sensor to light by adjusting the sensitivity, thereby affecting the brightness and contrast of the image; the greater the sensitivity, the higher the sensitivity, the higher the brightness of the image captured by the camera, and vice versa, the darker it will be, that is, the brightness of the image captured by the camera is also positively correlated with the gain of the camera. The aperture of the camera is a device used to control the amount of light that passes through the lens and enters the photosensitive surface in the fuselage, usually set in the lens. Generally speaking, when a camera lens takes a picture, it is impossible to change the diameter of the lens at will, but the amount of light passing through can be controlled by adding a polygonal or circular variable hole grating inside the lens. This device is called an aperture. The larger the aperture, the more light enters through the lens, and the higher the brightness of the image captured by the camera. Conversely, the lower the aperture, the lower the brightness of the image captured by the camera. That is, the brightness of the image captured by the camera is also positively correlated with the aperture size of the camera.

[0047] Optionally, when the target brightness distribution does not meet the preset brightness distribution conditions, if the grayscale value of the preset percentile in the target brightness distribution is less than the minimum threshold of the preset grayscale value range, then the average brightness of the images captured by multiple cameras is too low. Therefore, the display brightness parameters of the target projector and / or the camera parameters of at least one camera can be iteratively increased until the display brightness parameters and / or the camera parameters are increased and the target brightness distribution reacquired meets the preset brightness distribution conditions, and the increased display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the increased camera parameters are obtained as the calibrated camera parameters of the at least one camera. The display brightness parameters and camera parameters can be iteratively adjusted based on a preset convergence algorithm, and the preset convergence algorithm includes but is not limited to the commonly used binary search method, difference search method or trisection search method.

[0048] Optionally, when the target brightness distribution does not meet the preset brightness distribution conditions, if the grayscale value of the preset quantile in the target brightness distribution is greater than the maximum threshold of the preset grayscale value range, it indicates that the average brightness of the images captured by multiple cameras is too high. Therefore, the display brightness parameters of the target projector and / or the camera parameters of at least one camera can be iteratively reduced until the target brightness distribution condition is reacquired after the display brightness parameters and / or the camera parameters are reduced to meet the preset brightness distribution conditions, and the reduced display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the reduced camera parameters are obtained as the calibrated camera parameters of the at least one camera.

[0049] That is to say, when the grayscale value of the preset quantile in the re-acquired target brightness distribution is within the preset grayscale value range, the parameter calibration of the projection system is stopped, and the currently adjusted display brightness parameter is used as the calibrated display brightness parameter of the target projector, and the adjusted camera parameter is used as the calibrated camera parameter of the camera. In this way, after completing the calibration of the brightness parameters of each projector and between each projector and each camera, each projector can project a display screen with similar brightness, and each camera can capture an image with appropriate and similar brightness, so as to ensure the normal use of subsequent projector focus, geometric correction or three-dimensional reconstruction and other applications.

[0050] After step S130, if the target brightness distribution meets the preset brightness distribution conditions, the current display brightness parameters characterizing the target projector and the current camera parameters of each camera are valid parameters, thereby determining the current display brightness parameters of the target projector as the above-mentioned calibrated display brightness parameters, and determining the current camera parameters of each camera as the calibrated camera parameters of the camera.

[0051] In this embodiment, by iteratively adjusting the display brightness parameters and / or camera parameter combinations of the projector, the multi-camera multi-projection projection system can automatically and quickly adjust to reasonable parameters to ensure that under the combination of each projector and each camera, the image projected and displayed by the projector can be within a reasonable brightness range to prevent excessive darkness or overexposure; at the same time, it also ensures that each camera can capture an image whose brightness distribution meets the preset brightness distribution conditions, thereby ensuring the normal use of projector focus, geometric correction, and three-dimensional reconstruction functions.

[0052] Please refer to Figure 7 , Figure 7 A flow chart of a method for calibrating parameters of a projection system provided in another embodiment of the present application is shown below. Figure 7The parameter calibration method of the projection system provided in the embodiment of the present application is described in detail. The parameter calibration method of the projection system may include the following steps:

[0053] Step S210: projecting a white field image to a target area through a target projector, and capturing images of the target area through the multiple cameras to obtain multiple first images, and projecting a black field image to the target area through the target projector, and capturing images of the target area through the multiple cameras to obtain multiple second images, wherein the multiple second images correspond one-to-one to the multiple first images, and the target projector is any one of the multiple projectors.

[0054] Step S220: Obtain a difference image between each of the first images and its corresponding second image, and based on the difference image, determine a projection screen area formed by the target projector in each of the first images as a first projection screen area of ​​each of the first images.

[0055] Step S230: acquiring the brightness distribution of each first image according to the grayscale value of each pixel in the first projection picture area of ​​each first image, and obtaining a plurality of brightness distributions, wherein the plurality of brightness distributions correspond one-to-one to the plurality of cameras.

[0056] Step S240: obtaining an average grayscale value of grayscale values ​​of preset quantiles in the brightness distribution of all the first images as the target brightness distribution.

[0057] In this embodiment, the specific implementation of steps S210 to S240 can refer to the contents of the aforementioned embodiments and will not be described in detail here.

[0058] Step S250: If the average grayscale value is within the preset grayscale value range, and it is detected that the grayscale value of the preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, the camera parameters of the target camera used to shoot the target image are iteratively adjusted until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibrated camera parameters of the target camera, the target image is any first image among the multiple first images, and the specified brightness distribution is the brightness distribution of the first image re-captured by the target camera after the camera parameters are adjusted.

[0059] It can be understood that if the average grayscale value is within the preset grayscale value range, it indicates that the projection brightness of the target projector is within a reasonable brightness range. Further, the grayscale value of the preset quantile in the brightness distribution of each first image can be obtained to obtain multiple grayscale values, and the multiple grayscale values ​​correspond to multiple first images one by one. Optionally, if it is detected that the grayscale value of the preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, it indicates that the brightness of the image captured by the target camera used to capture the target image is not within a suitable brightness range. Therefore, the camera parameters of the target camera can be further iteratively adjusted until the grayscale value of the preset quantile of the brightness distribution of the first image re-captured by the target camera after adjusting the camera parameters is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibration camera parameters of the target camera. In this way, the brightness distribution of the images captured by each camera can be close.

[0060] Optionally, if the average grayscale value is within the preset grayscale value range, and the grayscale value of a preset quantile in the brightness distribution of the target image is less than the minimum threshold of the preset grayscale value range, it indicates that the brightness of the image captured by the target camera is low; therefore, the camera parameters of the target camera can be iteratively increased until the brightness distribution corresponding to the target camera acquired after the camera parameters are increased meets the preset brightness distribution conditions, and the increased camera parameters are obtained as the calibrated camera parameters.

[0061] It should be noted that when the camera parameters are iteratively increased, the exposure time of the camera is generally adjusted first, for example, the exposure time is increased. After increasing the exposure time of the camera, if the grayscale value of the preset quantile in the re-acquired specified brightness distribution is still not within the preset grayscale value range, the gain of the camera can be further increased to avoid directly adjusting the gain of the camera from the beginning, which introduces more noise into the camera shooting and other problems. If after increasing the gain of the camera, the grayscale value of the preset quantile in the re-acquired specified brightness distribution is still not within the preset grayscale value range, the aperture or gamma of the camera can be further increased until the grayscale value of the preset quantile in the re-acquired specified brightness distribution is within the preset grayscale value range, then the adjustment of the camera parameters is stopped, thereby obtaining the increased camera parameters as the calibration camera parameters.

[0062] Optionally, if the average grayscale value is within the preset grayscale value range, and the grayscale value of a preset quantile in the brightness distribution of the target image is greater than the maximum threshold of the preset grayscale value range, it indicates that the brightness of the image captured by the target camera is higher; therefore, the camera parameters of the target camera can be iteratively reduced until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the reduced camera parameters are obtained as the calibrated camera parameters.

[0063] Similarly, when the camera parameters are iteratively reduced, the exposure time of the camera is also adjusted first, for example, the exposure time is reduced. After reducing the exposure time of the camera, if the grayscale value of the preset quantile in the re-acquired specified brightness distribution is still not within the preset grayscale value range, the gain of the camera can be further reduced to avoid directly adjusting the gain of the camera from the beginning, which introduces more noise into the camera shooting and other problems. If after reducing the gain of the camera, the grayscale value of the preset quantile in the re-acquired specified brightness distribution is still not within the preset grayscale value range, the aperture or gamma of the camera can be further reduced until the grayscale value of the preset quantile in the re-acquired specified brightness distribution is within the preset grayscale value range, then the adjustment of the camera parameters is stopped, thereby obtaining the reduced camera parameters as the calibration camera parameters.

[0064] Step S260: If the average grayscale value is not within the preset grayscale value range, the display brightness parameters of the target projector are iteratively adjusted until the average grayscale value re-acquired after adjusting the display brightness parameters is within the preset grayscale value range, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and then the camera parameters of the target camera are iteratively adjusted until the grayscale value of the preset percentile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibrated camera parameters.

[0065] It can be understood that if the average grayscale value is not within the preset grayscale value range, it indicates that the projection brightness of the target projector is not yet within a reasonable brightness range. Therefore, the display brightness parameters of the target projector can be iteratively adjusted first until the average grayscale value re-acquired after the display brightness parameters are adjusted is within the preset grayscale value range, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector. That is to say, when the average grayscale value is not within the preset grayscale value range, the display brightness parameters of the target projector are calibrated first; that is, after the calibration of the display brightness parameters of the target projector is completed, that is, after the projection brightness of the target projector is within a reasonable brightness range, if the aforementioned target camera is detected, the camera parameters of the target camera are further iteratively adjusted to achieve the calibration of the camera parameters of the target camera, wherein the specific method of iteratively adjusting the camera parameters of the target camera can be referred to the aforementioned content, which will not be repeated here.

[0066] Optionally, if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is less than the minimum threshold of the preset grayscale value range, it indicates that the projection brightness of the target projector is too small. Therefore, the display brightness parameter of the target projector can be iteratively increased until the display brightness parameter is increased and the re-acquired average grayscale value is within the preset grayscale value range. The increased display brightness parameter is obtained as the calibrated display brightness parameter.

[0067] Optionally, if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is greater than the maximum threshold of the preset grayscale value range, it indicates that the projection brightness of the target projector is too large. Therefore, the display brightness parameter of the target projector can be iteratively increased or decreased until the display brightness parameter is reduced and the re-acquired average grayscale value is within the preset grayscale value range, and the reduced display brightness parameter is obtained as the calibrated display brightness parameter.

[0068] Optionally, if the grayscale value of the preset quantile in the fifth grayscale histogram is not within the preset grayscale value range, the initial brightness parameter of the adjusted target projector and / or the initial camera parameter of the adjusted target camera are iteratively adjusted, and if the number of iterative adjustments reaches a preset number threshold, and the preset condition is still not met, a prompt message is output, and the prompt message is used to prompt that the parameter calibration of the projection system has failed. The preset number threshold is a pre-set value; the output method of the prompt message can be display output, voice output, email output or SMS output, which is not limited in this embodiment.

[0069] For example, if one projector and N cameras are selected from the above projection system to calibrate the brightness parameters, any camera can capture the image projected by any projector. i projector (i.e., the target projector mentioned above), where i is an integer. ij The overall process of brightness parameter calibration can be found in Figure 8 First, initialize the projector settings. i The display brightness factor (i.e. the display brightness parameter mentioned above) and the camera parameters (exposure time, gain, aperture, etc.) of multiple cameras. i The white field image and the black field image are projected successively, and after being photographed by N cameras in sequence, the images are subtracted and binarized to generate a mask image. The white area in the mask image is the projection image of projector M. i The projection screen area is obtained to obtain the first projection screen area of ​​each first image. Then take the first image obtained by shooting the white field image as mentioned above, count the grayscale histogram of the first image in the white area (i.e., the projection screen area) of the mask, and calculate the grayscale value Z of the preset quantile (indicating the proportion exceeded, such as 0.90, 0.95, which can be set according to the scene requirements) in the grayscale histogram as the brightness distribution of each first image. Then obtain the average grayscale value of the grayscale values ​​of the preset quantile in the brightness distribution of all first images as the target brightness distribution; and then determine whether the average grayscale value is within the preset grayscale value range (Z min ,Z max )Inside.

[0070] Optionally, if the average gray value is within the preset gray value range (Z min ,Z max), and it is detected that the grayscale value of the preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, then the camera parameters of the target camera (for example, camera Nj among N cameras) used to shoot the target image are iteratively adjusted until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibration camera parameters of the target camera, the target image is any first image among the multiple first images, and the designated brightness distribution is the brightness distribution of the first image re-taken by the target camera after the camera parameters are adjusted. Specifically, if the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is less than the minimum threshold of the preset grayscale value range, then the camera parameters of the target camera are iteratively increased until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the increased camera parameters are obtained as the calibration camera parameters. If the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is greater than the maximum threshold of the preset grayscale value range, the camera parameters of the target camera are iteratively reduced until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the reduced camera parameters are obtained as the calibration camera parameters. That is, the effective brightness factor of the aforementioned 1 projector and the reasonable camera parameters of N cameras are obtained.

[0071] Optionally, if the average gray value is not within the preset gray value range (Z min ,Z max), the display brightness parameters of the target projector are iteratively adjusted until the average grayscale value reacquired after the display brightness parameters are adjusted is within the preset grayscale value range, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and then the camera parameters of the target camera (for example, camera Nj among N cameras) are iteratively adjusted until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibrated camera parameters. Specifically, if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is less than the minimum threshold of the preset grayscale value range, the display brightness parameter of the target projector is iteratively increased until the average grayscale value reacquired after the display brightness parameter is increased is within the preset grayscale value range, and the increased display brightness parameter is obtained as the calibrated display brightness parameter; if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is greater than the maximum threshold of the preset grayscale value range, the display brightness parameter of the target projector is iteratively increased and decreased until the average grayscale value reacquired after the display brightness parameter is decreased is within the preset grayscale value range, and the decreased display brightness parameter is obtained as the calibrated display brightness parameter. That is, the effective brightness factor of the aforementioned 1 projector and the reasonable camera parameters of N cameras are obtained.

[0072] It should be noted that the process of continuously adjusting the display brightness parameters of the projector and the camera parameters is achieved through a preset convergence algorithm, which includes but is not limited to a binary search method, an interpolation search method, a trisection search method, and the like.

[0073] In this embodiment, by iteratively adjusting the display brightness parameters and / or camera parameter combinations of the projector, the multi-camera multi-projection projection system can automatically and quickly adjust to reasonable parameters to ensure that the image projected and displayed by the projector can be within a reasonable brightness range under the combination of each projector and each camera to prevent the occurrence of over-darkness or over-exposure; at the same time, it also ensures that each camera can capture an image whose brightness distribution meets the preset brightness distribution conditions, thereby ensuring the normal use of the projector's focus, geometric correction, and three-dimensional reconstruction functions. In other words, the purpose of automatically adapting the image projected by the projector captured by the camera to the changes in ambient light and maintaining brightness consistency can be achieved.

[0074] Please refer to Fig. 9, which shows a structural block diagram of a parameter calibration device 300 for a projection system provided by an embodiment of the present application, wherein the projection system includes multiple projectors and multiple cameras. The device 300 may include: an image acquisition module 310, a projection area determination module 320, a brightness distribution acquisition module 330, and a parameter calibration module 340.

[0075] The image acquisition module 310 is used to project a white field image onto a target area through a target projector, and to capture images of the target area through the multiple cameras to obtain multiple first images, and to project a black field image onto the target area through the target projector, and to capture images of the target area through the multiple cameras to obtain multiple second images, wherein the multiple second images correspond one-to-one to the multiple first images, and the target projector is any one of the multiple projectors.

[0076] The projection area determination module 320 is used to obtain a difference image between each of the first images and its corresponding second image, and based on the difference image, determine a projection screen area formed by the projection of the target projector in each of the first images as the first projection screen area of ​​each of the first images.

[0077] The brightness distribution acquisition module 330 is used to obtain the brightness distribution of each first image according to the grayscale value of each pixel in the first projection picture area of ​​each first image, and obtain multiple brightness distributions, and the multiple brightness distributions correspond one-to-one to the multiple cameras.

[0078] The parameter calibration module 340 is used to iteratively adjust the display brightness parameters of the target projector and / or the camera parameters of the camera if the target brightness distribution does not meet the preset brightness distribution conditions, until the target brightness distribution conditions reacquired after adjusting the display brightness parameters and / or the camera parameters meet the preset brightness distribution conditions, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the adjusted camera parameters are obtained as the calibrated camera parameters of the camera, and the target brightness distribution conditions are obtained based on the multiple brightness distribution conditions.

[0079] In some embodiments, the brightness distribution acquisition module 330 may be specifically used to: acquire the grayscale histogram of each first image according to the grayscale value of each pixel in the first projection screen area of ​​each first image as the brightness distribution of each first image. The parameter calibration device 300 of the projection system may also include: an average grayscale acquisition module and a brightness distribution judgment module. Among them, the average grayscale acquisition module may be specifically used to acquire the average grayscale value of the grayscale values ​​of the preset quantiles in the brightness distribution of all the first images after acquiring the grayscale histogram of each first image according to the grayscale value of each pixel in the first projection screen area of ​​each first image as the brightness distribution of each first image as the target brightness distribution. The brightness distribution judgment module may be specifically used to determine that the target brightness distribution does not meet the preset brightness distribution condition if the average grayscale value is not within the preset grayscale value range; if the average grayscale value is within the preset grayscale value range, determine that the target brightness distribution meets the preset brightness distribution condition.

[0080] In this manner, the parameter calibration module 340 can be specifically used for: if the average grayscale value is within the preset grayscale value range, and it is detected that the grayscale value of the preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, iteratively adjusting the camera parameters of the target camera used to shoot the target image until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and obtaining the adjusted camera parameters as the calibrated camera parameters of the target camera, wherein the target image is any first image among the multiple first images, and the specified brightness distribution is after adjusting the camera parameters. the brightness distribution of the first image re-captured by the target camera; if the average grayscale value is not within the preset grayscale value range, the display brightness parameters of the target projector are iteratively adjusted until the average grayscale value re-acquired after adjusting the display brightness parameters is within the preset grayscale value range, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the camera parameters of the target camera are iteratively adjusted again until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibrated camera parameters.

[0081] In some embodiments, the parameter calibration module 340 can be specifically used to: if the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is less than the minimum threshold of the preset grayscale value range, then iteratively increase the camera parameters of the target camera until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and obtain the increased camera parameters as the calibration camera parameters; if the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is greater than the maximum threshold of the preset grayscale value range, then iteratively reduce the camera parameters of the target camera until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and obtain the reduced camera parameters as the calibration camera parameters.

[0082] In some embodiments, the parameter calibration module 340 can also be specifically used for: if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is less than the minimum threshold of the preset grayscale value range, then iteratively increasing the display brightness parameter of the target projector until the average grayscale value acquired after increasing the display brightness parameter is within the preset grayscale value range, and obtaining the increased display brightness parameter as the calibrated display brightness parameter; if the average grayscale value is not within the preset grayscale value range, and the average grayscale value is greater than the maximum threshold of the preset grayscale value range, then iteratively increasing or decreasing the display brightness parameter of the target projector until the average grayscale value acquired after reducing the display brightness parameter is within the preset grayscale value range, and obtaining the reduced display brightness parameter as the calibrated display brightness parameter.

[0083] In some embodiments, the projection area determination module 320 may include: a difference image acquisition unit and a projection image area determination unit. The difference image acquisition unit may be used to: if the camera is a black and white camera, obtain a difference image between each first image and its corresponding second image; if the camera is a color camera, obtain a first grayscale image corresponding to each first image, obtain a second grayscale image corresponding to each second image corresponding to the first image, and obtain a difference image between the first grayscale image and the second grayscale image. The projection image area determination unit may be used to binarize the difference image to obtain a binarized image corresponding to the difference image; obtain the area position of the white area in the binarized image; and determine an image area corresponding to the area position of the white area from each first image as the first projection image area of ​​each first image.

[0084] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here.

[0085] In several embodiments provided in the present application, the coupling between modules may be electrical, mechanical or other forms of coupling.

[0086] In addition, each functional module in each embodiment of the present application can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above integrated modules can be implemented in the form of hardware or software functional modules.

[0087] In summary, by iteratively adjusting the display brightness parameters and / or camera parameter combinations of the projector, the multi-camera multi-projection projection system can automatically and quickly adjust to reasonable parameters to ensure that the image projected and displayed by the projector can be within a reasonable brightness range under the combination of each projector and each camera to prevent the occurrence of over-darkness or over-exposure; at the same time, it also ensures that each camera can capture an image whose brightness distribution meets the preset brightness distribution conditions, thereby ensuring the normal use of the projector's focus, geometric correction, and three-dimensional reconstruction functions. In other words, the image projected by the projector captured by the camera can automatically adapt to changes in ambient light and maintain brightness consistency.

[0088] The following will be combined Fig.10 An electronic device provided by the present application is described.

[0089] Reference Fig.10 , Fig.10 The structural block diagram of an electronic device 400 provided in an embodiment of the present application is shown, and the above method provided in an embodiment of the present application can be executed by the electronic device 400. The electronic device can be an electronic terminal with a data processing function, and the electronic terminal includes but is not limited to a smart phone, a tablet computer, a laptop computer, and a desktop computer.

[0090] The electronic device 400 in the embodiment of the present application may include one or more of the following components: a processor 401, a memory 402, and one or more applications, wherein the one or more applications may be stored in the memory 402 and configured to be executed by one or more processors 401, and the one or more programs are configured to execute the method as described in the aforementioned method embodiment.

[0091] The processor 401 may include one or more processing cores. The processor 401 uses various interfaces and lines to connect the various parts of the entire electronic device 400, and executes various functions and processes data of the electronic device 400 by running or executing instructions, programs, code sets or instruction sets stored in the memory 402, and calling data stored in the memory 402. Optionally, the processor 401 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 401 can integrate one or a combination of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modem. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing display content; and the modem is used to process wireless communications. It can be understood that the above-mentioned modem can also be integrated into the processor 401 and implemented separately through a communication chip.

[0092] The memory 402 may include a random access memory (RAM) or a read-only memory (ROM). The memory 402 may be used to store instructions, programs, codes, code sets or instruction sets. The memory 402 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the following various method embodiments, etc. The data storage area may also store data (such as the various corresponding relationships described above) created by the electronic device 400 during use.

[0093] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here.

[0094] In several embodiments provided in the present application, the coupling or direct coupling or communication connection between the modules shown or discussed may be an indirect coupling or communication connection through some interfaces, devices or modules, which may be electrical, mechanical or other forms.

[0095] In addition, each functional module in each embodiment of the present application can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above integrated modules can be implemented in the form of hardware or software functional modules.

[0096] Please refer to Fig.11 , which shows a structural block diagram of a computer-readable storage medium provided in an embodiment of the present application. The computer-readable medium 500 stores program codes, which can be called by a processor to execute the method described in the above method embodiment.

[0097] The computer readable storage medium 500 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk, or a ROM. Optionally, the computer readable storage medium 500 includes a non-transitory computer-readable storage medium. The computer readable storage medium 500 has storage space for program code 510 that performs any method step of the above method. These program codes can be read from or written to one or more computer program products. The program code 510 can be compressed, for example, in an appropriate form.

[0098] In some embodiments, a computer program product or computer program is provided, the computer program product or computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device performs the steps in the above-mentioned method embodiments.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calibrating parameters of a projection system, characterized in that: The projection system includes a plurality of projectors and a plurality of cameras, and the method includes: Projecting a white field image onto a target area through a target projector, and photographing the target area through the multiple cameras to obtain a plurality of first images, and projecting a black field image onto the target area through the target projector, and photographing the target area through the multiple cameras to obtain a plurality of second images, wherein the plurality of second images correspond to the plurality of first images one by one, and the target projector is any one of the plurality of projectors; Acquire a difference image between each of the first images and its corresponding second image, and determine, based on the difference image, a projection screen area formed by the target projector in each of the first images as a first projection screen area of ​​each of the first images; Acquire the brightness distribution of each first image according to the gray value of each pixel in the first projection picture area of ​​each first image, and obtain a plurality of brightness distributions, wherein the plurality of brightness distributions correspond one-to-one to the plurality of cameras; If the target brightness distribution does not meet the preset brightness distribution conditions, the display brightness parameters of the target projector and / or the camera parameters of the camera are iteratively adjusted until the target brightness distribution obtained after adjusting the display brightness parameters and / or the camera parameters meets the preset brightness distribution conditions, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the adjusted camera parameters are obtained as the calibrated camera parameters of the camera, and the target brightness distribution is obtained based on the multiple brightness distribution conditions.

2. The method according to claim 1, characterized in that The obtaining, according to the gray value of each pixel in the first projection picture area of ​​each first image, the brightness distribution of each first image comprises: According to the grayscale value of each pixel point in the first projection picture area of ​​each first image, a grayscale histogram of each first image is obtained as the brightness distribution of each first image; After obtaining a grayscale histogram of each first image as the brightness distribution of each first image according to the grayscale value of each pixel in the first projection picture area of ​​each first image, the method further includes: Obtaining an average grayscale value of grayscale values ​​of preset quantiles in the brightness distribution of all the first images as the target brightness distribution; If the average grayscale value is not within the preset grayscale value range, it is determined that the target brightness distribution does not meet the preset brightness distribution condition; If the average grayscale value is within the preset grayscale value range, it is determined that the target brightness distribution condition meets the preset brightness distribution condition.

3. The method according to claim 2, characterized in that If the target brightness distribution does not meet the preset brightness distribution conditions, the display brightness parameters of the target projector and / or the camera parameters of the target camera are iteratively adjusted until the target brightness distribution condition reacquired after the display brightness parameters and / or the camera parameters are adjusted meets the preset brightness distribution conditions, the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and the adjusted camera parameters are obtained as the calibrated camera parameters of the target camera, including: If the average grayscale value is within the preset grayscale value range, and it is detected that the grayscale value of a preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, iteratively adjust the camera parameters of the target camera used to shoot the target image until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and obtain the adjusted camera parameters as the calibrated camera parameters of the target camera, the target image is any first image among the multiple first images, and the specified brightness distribution is the brightness distribution of the first image re-shot by the target camera after the camera parameters are adjusted; If the average grayscale value is not within the preset grayscale value range, the display brightness parameters of the target projector are iteratively adjusted until the average grayscale value re-acquired after adjusting the display brightness parameters is within the preset grayscale value range, and the adjusted display brightness parameters are obtained as the calibrated display brightness parameters of the target projector, and then the camera parameters of the target camera are iteratively adjusted until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibrated camera parameters.

4. The method according to claim 3, characterized in that: If the average grayscale value is within the preset grayscale value range, and it is detected that the grayscale value of a preset quantile in the brightness distribution of the target image is not within the preset grayscale value range, the camera parameters of the target camera used to shoot the target image are iteratively adjusted until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the adjusted camera parameters are obtained as the calibration camera parameters of the target camera, wherein the target image is any first image among the multiple first images, and the specified brightness distribution is the brightness distribution of the first image re-shot by the target camera after the camera parameters are adjusted, including: If the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is less than the minimum threshold of the preset grayscale value range, the camera parameters of the target camera are iteratively increased until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the increased camera parameters are obtained as the calibration camera parameters; If the average grayscale value is within the preset grayscale value range, and the grayscale value of the preset quantile in the brightness distribution of the target image is greater than the maximum threshold of the preset grayscale value range, the camera parameters of the target camera are iteratively reduced until the grayscale value of the preset quantile in the acquired specified brightness distribution is within the preset grayscale value range, and the reduced camera parameters are obtained as the calibrated camera parameters.

5. The method according to claim 3, characterized in that: If the average grayscale value is not within the preset grayscale value range, iteratively adjusting the display brightness parameter of the target projector until the average grayscale value re-acquired after adjusting the display brightness parameter is within the preset grayscale value range, and obtaining the adjusted display brightness parameter as the calibrated display brightness parameter of the target projector, including: If the average grayscale value is not within the preset grayscale value range, and the average grayscale value is less than the minimum threshold of the preset grayscale value range, iteratively increasing the display brightness parameter of the target projector until the average grayscale value re-obtained after increasing the display brightness parameter is within the preset grayscale value range, and obtaining the increased display brightness parameter as the calibrated display brightness parameter; If the average grayscale value is not within the preset grayscale value range, and the average grayscale value is greater than the maximum threshold of the preset grayscale value range, the display brightness parameter of the target projector is iteratively increased or decreased until the display brightness parameter is reduced and the re-acquired average grayscale value is within the preset grayscale value range, and the reduced display brightness parameter is obtained as the calibrated display brightness parameter.

6. The method according to any one of claims 1 to 5, characterized in that: The acquiring a difference image between each of the first images and its corresponding second image comprises: If the camera is a black and white camera, obtaining a difference image between each of the first images and its corresponding second image; If the camera is a color camera, a first grayscale image corresponding to each of the first images is obtained, a second grayscale image corresponding to each of the second images corresponding to the first images is obtained, and a difference image between the first grayscale image and the second grayscale image is obtained.

7. The method according to any one of claims 1 to 5, characterized in that: The step of determining, based on the difference image, a projection screen area formed by projection of the target projector in each of the first images as a first projection screen area of ​​each of the first images comprises: Performing binarization processing on the difference image to obtain a binarized image corresponding to the difference image; Obtaining the area position of the white area in the binary image; An image region corresponding to the region position of the white region is determined from each of the first images as a first projection image region of each of the first images.

8. A parameter calibration device for a projection system, characterized in that: The projection system includes a plurality of projectors and a plurality of cameras, and the device includes: an image acquisition module, configured to project a white field image onto a target area through a target projector, and to capture images of the target area through the multiple cameras to obtain multiple first images, and to project a black field image onto the target area through the target projector, and to capture images of the target area through the multiple cameras to obtain multiple second images, wherein the multiple second images correspond to the multiple first images in a one-to-one manner, and the target projector is any one of the multiple projectors; a projection area determination module, configured to obtain a difference image between each of the first images and its corresponding second image, and determine, based on the difference image, a projection screen area formed by the projection of the target projector in each of the first images as a first projection screen area of ​​each of the first images; a brightness distribution acquisition module, configured to acquire the brightness distribution of each first image according to the gray value of each pixel in the first projection picture area of ​​each first image, and obtain a plurality of brightness distributions, wherein the plurality of brightness distributions correspond one-to-one to the plurality of cameras; A parameter calibration module is used to iteratively adjust the display brightness parameters of the target projector and / or the camera parameters of the camera if the target brightness distribution does not meet the preset brightness distribution conditions, until the target brightness distribution condition reacquired after adjusting the display brightness parameters and / or the camera parameters meets the preset brightness distribution conditions, and obtain the adjusted display brightness parameters as the calibrated display brightness parameters of the target projector, and obtain the adjusted camera parameters as the calibrated camera parameters of the camera, and the target brightness distribution condition is obtained based on the multiple brightness distribution conditions.

9. An electronic device, characterized in that: The electronic device comprises: one or more processors; Memory; One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs are configured to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 7.

Images