Calibration board, calibration method, calibration device, storage medium and electronic device

Abstract

The present application provides a calibration board, a calibration method, a calibration device, a storage medium, and an electronic device. The calibration board is used for calibrating camera parameters. The calibration board includes a plurality of first regions and a plurality of second regions. The plurality of first regions and the plurality of second regions are alternately arranged and connected in sequence. The first region has a first color, and the second region has at least a second color. At least one of the second regions includes at least one first sub-region and a plurality of second sub-regions. The at least one first sub-region and the plurality of second sub-regions are connected as a whole. The first sub-region has the second color, and the second sub-region has a third color. Wherein, the first color is different from the second color, and the second color is different from the third color. The calibration board of the present application can be used for calibrating the parameters of cameras with at least two different field-of-view angles. It has a simple structure, is easy to manufacture and produce, can improve the efficiency of camera parameter calibration, and save the test cost of the camera.

Description

Technical Field

[0001] This application relates to the technical fields of image processing, computer vision, and camera calibration, and particularly relates to a calibration board, a calibration method, a calibration device, a computer-readable storage medium, and an electronic device. Background Art

[0002] In the process of image measurement and machine vision applications, in order to determine the mutual relationship between the three-dimensional geometric position of a certain point on the surface of a spatial object and its corresponding point in the image, it is necessary to establish a geometric model of camera imaging. These geometric model parameters are camera parameters. Under most conditions, these parameters must be obtained through experiments and calculations, and this process of solving the parameters is called camera calibration. Whether in image measurement or machine vision applications, the calibration of camera parameters is a very crucial link. The accuracy of its calibration results and the stability of the algorithm directly affect the accuracy of the results generated by the camera's work. Therefore, doing a good job in camera calibration is a prerequisite for doing subsequent work, and its calibration includes parameters such as camera internal parameters, external parameters, and distortion.

[0003] In the existing technology, a calibration board is used to calibrate camera parameters. However, the existing calibration board has a single function, and one calibration board can only be used for a specific camera to calibrate camera parameters. Summary of the Invention

[0004] In view of the above problems, in a first aspect, this application provides a calibration board for calibrating camera parameters. The calibration board includes a plurality of first regions and a plurality of second regions, the plurality of first regions and the plurality of second regions are alternately arranged and connected in sequence. The first region has a first color, and the second region has at least a second color; at least one of the second regions includes at least one first sub-region and a plurality of second sub-regions, the at least one first sub-region and the plurality of second sub-regions are connected as a whole, the first sub-region has the second color, and the second sub-region has a third color; wherein, the first color is different from the second color, and the second color is different from the third color.

[0005] According to the calibration board of the present application, the first area with the first color and the second area with at least the second color are alternately arranged and connected in sequence. Since the first color is different from the second color, there will be a gray value contrast between the first color and the second color. Therefore, there will be multiple feature areas that can be recognized depending on the difference in gray value contrast in the alternately connected first area and second area, which can be used for parameter calibration of a camera. After photographing the part of the calibration board that includes multiple first areas and multiple second areas, the parameters of this camera are calibrated according to the quantity information and position information of the feature areas in the captured image; at least one second area includes at least one first sub-area and multiple second sub-areas. The first sub-area has the second color, while the second sub-area has a third color different from the second color, that is, at least one second area has a third color in addition to the second color. There will also be a feature area that can be recognized depending on the difference in gray value contrast between the at least one first sub-area and the multiple second sub-areas connected as a whole, which can be used for another camera with a smaller field of view. After photographing the part of the calibration board that includes at least one first sub-area and multiple second sub-areas, the parameters of this camera are calibrated according to the quantity information and position information of the feature areas in the captured image. The calibration board of the present application has diverse functions and can be used for parameter calibration of at least two cameras with different field of view sizes. Its structure is simple and easy to manufacture, which can improve the efficiency of camera parameter calibration and save the test cost of the camera.

[0006] In an alternative embodiment, the multiple first areas and the multiple second areas are both squares. The multiple first areas and the multiple second areas are alternately arranged and connected in sequence to form a first checkerboard.

[0007] Setting the multiple first areas and the multiple second areas as squares and alternately connecting them into a first checkerboard helps standardize the calibration pattern of the calibration board, makes the calibration board easier to produce, and the difference in gray value contrast is relatively uniform, which is beneficial to better recognizing the feature areas in the captured image. The corner points adjacent to two adjacent same-color squares can be easily recognized as feature points, improving the efficiency of camera parameter calibration.

[0008] In an alternative embodiment, at least one second area includes multiple first sub-areas and multiple second sub-areas. The multiple first sub-areas and the multiple second sub-areas are both squares. The multiple first sub-areas and the multiple second sub-areas are alternately arranged and connected in sequence to form a second checkerboard, and the third color is different from the first color.

[0009] A plurality of first sub-regions and a plurality of second sub-regions are set as squares and alternately connected to form a second checkerboard. That is, the first checkerboard is a large grid and the second checkerboard is a small grid. The calibration board has two levels of nested checkerboards. The first checkerboard can be used for parameter calibration of cameras with a larger field of view angle, and the second checkerboard can be used for parameter calibration of cameras with a smaller field of view angle. The function of the calibration board is more diversified and the calibration efficiency is higher. The first color is different from both the third color and the second color, and there is a contrast difference in gray values, which can make it easy for the camera to capture the feature regions brought by the gray value difference, and it is easy to identify the corner points adjacent to two adjacent same-color grids as feature points, thereby facilitating subsequent image processing and improving the camera parameter calibration efficiency.

[0010] In an alternative embodiment, at least one of the second regions includes the first sub-region and a plurality of the second sub-regions, the first sub-region is connected to each of the second sub-regions as a whole, and the third color is the same as the first color.

[0011] Connecting the first sub-region and a plurality of second sub-regions as a whole, the third color is the same as the first color, and the third color is different from the second color. Therefore, cameras with a larger field of view angle can identify feature regions according to the differences between the first color and the second color of the plurality of first regions and the plurality of second regions, and cameras with a smaller field of view angle can identify feature regions according to the differences between the second color and the third color of the first sub-region and the plurality of second sub-regions. The function of the calibration board is more diversified, the subsequent image processing of the calibration board captured by the camera is more convenient, and the calibration efficiency of the camera parameters is higher.

[0012] In an alternative embodiment, the shapes of the plurality of second sub-regions include at least one of a circle, a rectangle, an ellipse, a triangle, a parallelogram, and a star.

[0013] Setting the plurality of second sub-regions as one or more regular shapes makes it easy to identify the centroid points of the second sub-regions as feature points in the captured image, and it is convenient to calibrate the camera parameters according to the information of these feature points, and the calibration efficiency of the camera parameters is higher.

[0014] In a second aspect, the present application provides a calibration method for calibrating camera parameters, including:

[0015] Obtain a calibration image, wherein the calibration image includes a plurality of first regions and a plurality of second regions, the plurality of first regions and the plurality of second regions are alternately arranged and connected in sequence, the first region has a first color, and the second region has at least a second color; at least one of the second regions includes at least one first sub-region and a plurality of second sub-regions, the at least one first sub-region and the plurality of second sub-regions are connected as a whole, the first sub-region has a second color, and the second sub-region has a third color; wherein, the first color is different from the second color, the second color is different from the third color, the calibration image has a first feature point, and at least one of the second regions has a second feature point;

[0016] When the total number of the first regions and the second regions is greater than or equal to a preset threshold, obtain a first number of the first feature points and a first coordinate of each of the first feature points, and obtain calibration data of a camera that captures the calibration image according to the first number and the first coordinate; and, when the total number of the first regions and the second regions is less than the preset threshold, obtain a second number of the second feature points and a second coordinate of each of the second feature points, and obtain calibration data of a camera that captures the calibration image according to the second number and the second coordinate.

[0017] According to the calibration method of the present application, after obtaining the calibration image of the calibration board, the first regions with the first color and the second regions with the second color in the image are alternately arranged and connected in sequence. Since the first color is different from the second color, there will be a gray value contrast between the first color and the second color. Therefore, there will be a plurality of first feature points that can be identified by relying on the gray value contrast in the alternately connected first regions and second regions. When the total number of the first regions and the second regions is greater than or equal to the preset threshold, obtain the number and coordinates of these first feature points, and the parameters of a camera with a larger field of view angle can be calibrated according to the number information and position information of the first feature points; at least one second region includes at least one first sub-region and a plurality of second sub-regions, the first sub-region has a second color, and the second sub-region has a third color different from the second color, that is, at least one second region has a third color in addition to the second color. There will also be a second feature point that can be identified by relying on the gray value contrast between the at least one first sub-region and the plurality of second sub-regions connected as a whole. When the total number of the first regions and the second regions is less than the preset threshold, obtain the number and coordinates of these second feature points, and the parameters of a camera with a smaller field of view angle can be calibrated according to the number information and position information of the second feature points. The calibration method of the present application has various functions and can be used for calibrating the parameters of at least two cameras with different field of view angles. The calibration process is simple and easy to implement, which can improve the efficiency of camera parameter calibration and save the test cost of the camera.

[0018] In an alternative embodiment, a plurality of the first regions and a plurality of the second regions are both squares, and corner points of the first regions are the first feature points. The obtaining of the first quantity of the first feature points and the first coordinates of each of the first feature points includes:

[0019] Perform binarization processing on the calibration image, set the third color to the second color, and obtain the first quantity of the corner points of the first regions and the first coordinates of each of the corner points of the first regions.

[0020] By performing binarization processing on the calibration image and setting the third color different from the second color in the image to the second color, in this way, the first sub-regions and the second sub-regions are connected into an integral body without color difference. The feature information that can be recognized is the first feature points generated due to the gray value difference caused by color between the first regions and the second regions, that is, the corner points of the first regions. It can adapt to a camera with a larger field of view angle to capture enough first feature points for calibrating parameters, and the feature recognition is more accurate; it prevents the feature information of the first sub-regions and multiple second sub-regions from being mixed therein, generating too much feature information and interfering with feature recognition, and the feature recognition is more sensitive.

[0021] In an alternative embodiment, a plurality of the first sub-regions and a plurality of the second sub-regions are both squares, and corner points of the second sub-regions are the second feature points. The obtaining of the second quantity of the second feature points and the second coordinates of each of the second feature points includes:

[0022] Perform binarization processing on the calibration image, set the third color to the first color, and obtain the second quantity of the corner points of the second sub-regions and the second coordinates of each of the corner points of the second sub-regions.

[0023] By performing binarization processing on the calibration image and setting the third color different from the second color in the image to the first color, in this way, a plurality of first sub-regions and a plurality of second sub-regions are connected into an integral body with color difference. For the calibration image captured by a camera with a smaller field of view angle, the entire image of the object being photographed cannot be captured, and the feature information generated due to the color difference between the first regions and the second regions is insufficient. However, it is easier to obtain the feature information contained in a plurality of first sub-regions and a plurality of second sub-regions, that is, the second feature points that are the corner points of the second sub-regions. The calibration method is simple and easy to implement, and the calibration efficiency is high.

[0024] In an alternative embodiment, the centroid points of the second sub-regions are the second feature points. The obtaining of the second quantity of the second feature points and the second coordinates of each of the second feature points includes:

[0025] Obtain the centroid points of each of the second sub-regions, and obtain the second quantity of the centroid points and the second coordinates of each of the centroid points.

[0026] By comparing the gray - scale value differences between the second sub - regions and the first sub - regions, multiple second sub - regions are identified, and the centroid points are found for each second sub - region. The centroid points of each second sub - region are used as the second feature points for the parameter calibration of the camera with a smaller field of view angle. The multiple first feature points in the first region and the second region that can be identified by the gray - scale value comparison differences are used for the parameter calibration of the camera with a larger field of view angle. The calibration method is simple and easy to implement, and the calibration efficiency is high, which can meet the calibration requirements of cameras with different field of view angles simultaneously.

[0027] In an alternative embodiment, after obtaining the calibration image, the method further includes:

[0028] Obtaining the total number of the first region and the second region; and

[0029] Comparing the total number with the preset threshold.

[0030] By obtaining the total number of the first region and the second region, it is judged whether the information captured in the image is sufficient according to the size relationship between the total number and the preset threshold. When the total number of the first region and the second region is greater than or equal to the preset threshold, the first feature points are sufficient for the external parameter calibration of the camera. When the total number of the first region and the second region is less than the preset threshold, the first feature points are not sufficient for the parameter calibration of the camera, and the second feature points need to be used for the parameter calibration of the camera. The calibration method is simple and easy to implement, and the calibration efficiency is high, which can meet the calibration requirements of cameras with different field of view angles simultaneously.

[0031] In a third aspect, the present application also provides a calibration device, including:

[0032] An image acquisition unit, configured to acquire a calibration image, wherein the calibration image includes multiple first regions and multiple second regions, the multiple first regions and the multiple second regions are alternately arranged and connected in sequence, the first region has a first color, and the second region has at least a second color; at least one of the second regions includes at least one first sub - region and multiple second sub - regions, the at least one first sub - region and the multiple second sub - regions are connected as a whole, the first sub - region has a second color, and the second sub - region has a third color; wherein, the first color is different from the second color, the second color is different from the third color, the calibration image has first feature points, and at least one of the second regions has second feature points;

[0033] An image processing unit, configured to obtain a first quantity of the first feature points and first coordinates of each of the first feature points when a total quantity of the first region and the second region is greater than or equal to a preset threshold, and obtain calibration data of a camera that captures the calibration image according to the first quantity and the first coordinates; and when the total quantity of the first region and the second region is less than the preset threshold, the image processing unit is configured to obtain a second quantity of the second feature points and second coordinates of each of the second feature points, and obtain calibration data of the camera that captures the calibration image according to the second quantity and the second coordinates.

[0034] According to the calibration device of the present application, after the image acquisition unit acquires a calibration image of a calibration board, a first region with a first color and a second region with a second color in the image are alternately arranged and connected in sequence. Since the first color is different from the second color, there will be a gray value contrast between the first color and the second color. Therefore, there will be multiple first feature points that can be identified by relying on the difference in gray value contrast in the alternately connected first region and second region. When the total quantity of the first region and the second region is greater than or equal to a preset threshold, the image processing unit acquires the quantity and coordinates of these first feature points, and can calibrate the parameters of a camera with a larger field of view according to the quantity information and position information of the first feature points; at least one second region includes at least one first sub-region and multiple second sub-regions. The first sub-region has the second color, and the second sub-region has a third color different from the second color. That is, at least one second region has not only the second color but also the third color. There will also be second feature points that can be identified by relying on the difference in gray value contrast between the at least one first sub-region and the multiple second sub-regions connected as a whole. When the total quantity of the first region and the second region is less than the preset threshold, the image processing unit acquires the quantity and coordinates of these second feature points, and can calibrate the parameters of a camera with a smaller field of view according to the quantity information and position information of the second feature points. The calibration device of the present application has various functions and can be used for calibrating the parameters of at least two cameras with different field of view sizes. The calibration process is simple and easy to implement, which can improve the efficiency of camera parameter calibration and save the test cost of the camera.

[0035] In an optional embodiment, a corner point of the first region is the first feature point, and the image processing unit further includes:

[0036] A first processing sub-unit, configured to perform binarization processing on the calibration image, set the third color to the second color, and obtain a first quantity of the corner points of the first region and first coordinates of each of the corner points of the first region.

[0037] The calibration image is binarized by the first processing subunit, and the third color different from the second color in the image is set as the second color. In this way, the first sub-region and the second sub-region are connected as an entity without color difference, and the feature information that can be recognized is the first feature points generated by the gray value difference caused by the color difference between the first region and the second region, that is, the corner points of the first region. It can adapt to cameras with a larger field of view angle to capture enough first feature points for calibrating parameters, and the feature recognition is more accurate; it prevents the feature information of the first sub-region and multiple second sub-regions from being mixed in, generating too much feature information and interfering with feature recognition, and the feature recognition is more sensitive.

[0038] In an alternative embodiment, the second sub-region is a square grid, and the corner points of the second sub-region are the second feature points. The image processing unit further includes:

[0039] A second processing subunit, which is configured to binarize the calibration image, set the third color as the first color, and obtain the second quantity of the corner points of the second sub-region and the second coordinates of the corner points of each second sub-region.

[0040] The calibration image is binarized by the second processing subunit, and the third color different from the second color in the image is set as the first color. In this way, multiple first sub-regions and multiple second sub-regions are connected as an entity with color difference. For the calibration image captured by a camera with a smaller field of view angle, the entire picture of the object being photographed cannot be captured, and the feature information generated by the color difference between the first region and the second region is insufficient. However, it is easier to obtain the feature information contained in multiple first sub-regions and multiple second sub-regions, that is, the second feature points that are the corner points of the second sub-region. The calibration method is simple and easy to implement, and the calibration efficiency is high.

[0041] In an alternative embodiment, the centroid point of the second sub-region is the second feature point. The image processing unit further includes:

[0042] A third processing subunit, which is configured to obtain the centroid point of each second sub-region, and obtain the second quantity of the centroid points and the second coordinates of each centroid point.

[0043] By comparing the gray value differences caused by the color between the second sub-region and the first sub-region through the third processing subunit, multiple second sub-regions are identified, and the centroid point of each second sub-region is found. The centroid point of each second sub-region is used as the second feature point for parameter calibration of a camera with a smaller field of view angle, and the multiple first feature points that can be recognized by the difference in gray value comparison caused by the color between the first region and the second region are used for parameter calibration of a camera with a larger field of view angle. The calibration method is simple and easy to implement, and the calibration efficiency is high, and it can meet the calibration of cameras with different field of view angles at the same time.

[0044] In an alternative embodiment, the calibration device further includes:

[0045] A comparison unit, which is configured to obtain the total quantity of the first area and the second area, and compare the total quantity with the preset threshold.

[0046] By using the comparison unit to obtain the total quantity of the first area and the second area, it is determined whether the information of the image capture is sufficient according to the magnitude relationship between the total quantity and the preset threshold; when the total quantity of the first area and the second area is greater than or equal to the preset threshold, the first feature points are sufficient for the parameter calibration of the camera; when the total quantity of the first area and the second area is less than the preset threshold, the first feature points are not sufficient for the parameter calibration of the camera, and the second feature points are used for the parameter calibration of the camera. The calibration method is simple and easy to implement, and has high calibration efficiency, and can meet the calibration of cameras with different field of view angles at the same time.

[0047] In a fourth aspect, the present application further provides a computer-readable storage medium, which stores executable program codes, and the computer-executable program codes are used to cause a computer to execute the calibration method as described above.

[0048] According to the executable program codes stored in the computer-readable storage medium of the present application, the calibration method as described above can be executed to calibrate the parameters of the camera, which can be applied to various types of cameras, and the calibration of the camera parameters is simple and easy to implement, and has high calibration efficiency.

[0049] In a fifth aspect, the present application further provides an electronic device, which includes a processor and a memory, and the memory stores program codes executable by the processor. When the program codes are called and executed by the processor, the calibration method as described above is executed.

[0050] According to the electronic device of the present application, the memory stores program codes executable by the processor for executing the above calibration method to calibrate the parameters of the camera, which can be applied to various types of cameras, and the calibration of the camera parameters is simple and easy to implement, and has high calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0052] Figure 1 It is a schematic diagram of a calibration board according to an embodiment of the present application.

[0053] Figure 2 is Figure 1 An enlarged view of part A in

[0054] Figure 3 Schematic diagram of a calibration board according to another embodiment of the present application.

[0055] Figure 4 is Figure 3 An enlarged schematic view of the second area in

[0056] Figure 5 Schematic diagram of a calibration image according to an embodiment of the present application.

[0057] Figure 6 Schematic diagram of a calibration image according to another embodiment of the present application.

[0058] Figure 7 Schematic diagram of a calibration image according to still another embodiment of the present application.

[0059] Figure 8 Schematic diagram of a calibration image according to yet another embodiment of the present application.

[0060] Figure 9 Schematic diagram of a calibration method according to an embodiment of the present application.

[0061] Figure 10 Schematic diagram of a calibration method according to another embodiment of the present application.

[0062] Figure 11 Schematic diagram of a calibration method according to still another embodiment of the present application.

[0063] Figure 12 Schematic diagram of a calibration method according to yet another embodiment of the present application.

[0064] Figure 13 Schematic diagram of a calibration method according to another embodiment of the present application.

[0065] Figure 14 Schematic diagram of a calibration method according to yet another embodiment of the present application.

[0066] Figure 15 Structural block diagram of a calibration device according to an embodiment of the present application.

[0067] Figure 16 Structural block diagram of an electronic device according to an embodiment of the present application.

[0068] Description of reference numerals:

[0069] 100 - calibration board, 1 - first area, 2 - second area, 21 - first sub - area, 22 - second sub - area, 110 - calibration image, 200 - calibration device, 201 - image acquisition unit, 202 - image processing unit, 2021 - first processing sub - unit, 2022 - second processing sub - unit, 2023 - third processing sub - unit, 203 - comparison unit, 300 - electronic device, 301 - processor, 302 - memory. Detailed implementation manner

[0070] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

[0071] In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation, or be constructed and operated in a specific orientation.

[0072] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above - mentioned terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0073] In addition, the terms "install", "set", "be provided with", "connect", "be connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there is internal communication between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above - mentioned terms in this application can be understood according to specific circumstances.

[0074] In addition, terms such as "first", "second", etc. are mainly used to distinguish different devices, components or parts (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, components or parts. Unless otherwise specified, the meaning of "a plurality of" is two or more. It should be noted that for the convenience of description, in the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted.

[0075] In order to calibrate the parameters of a camera, a calibration board with a checkerboard pattern is used. Usually, the size of each individual grid of the checkerboard pattern on the calibration board is the same. When the size of a single grid on the calibration board is determined, the number of corner points on the calibration board is also correspondingly determined. When this calibration board is applied to calibrate the parameters of cameras with different field of view angles, at the same object distance, the number of grids included in the images of the checkerboard pattern obtained by cameras with different field of view angles is different, and the number of corner points is also different. Therefore, it is difficult to enable cameras with different field of view angles (especially cameras with a small field of view angle) to capture enough feature points for camera parameter calibration.

[0076] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. It should be noted that for the convenience of description, in the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted.

[0077] In a first aspect, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the embodiments of the present application provide a calibration board 100 for calibrating camera parameters. The calibration board 100 includes a plurality of first regions 1 and a plurality of second regions 2. The plurality of first regions 1 and the plurality of second regions 2 are alternately arranged and connected in sequence. The first region 1 has a first color, and the second region 2 has at least a second color; at least one second region 2 includes at least one first sub-region 21 and a plurality of second sub-regions 22. At least one first sub-region 21 and the plurality of second sub-regions 22 are connected as a whole. The first sub-region 21 has the second color, and the second sub-region 22 has a third color; wherein, the first color is different from the second color, and the second color is different from the third color.

[0078] The calibration board 100 of the embodiments of the present application can be applied to parameter calibration of cameras of electronic devices with cameras, such as cameras, video cameras, mobile phones, tablet computers, e-readers, vehicle-mounted cameras, security monitoring devices, video doorbells, dash cams, smart watches, smart glasses, etc. Such as the internal parameters, external parameters, distortion parameters, etc. of the camera, external parameters such as rotation parameters and translation parameters, and distortion parameters such as radial distortion parameters and tangential distortion parameters.

[0079] According to the calibration board 100 of the present application, the first area 1 with the first color and the second area 2 with at least the second color are alternately arranged and connected in sequence. Since the first color is different from the second color, there will be a grayscale value contrast between the first color and the second color. Therefore, there will be multiple feature areas that can be identified by relying on the difference in grayscale value contrast in the alternately connected first area 1 and second area 2, which can be used for parameter calibration of a camera. After photographing the part of the calibration board 100 including multiple first areas 1 and multiple second areas 2, the parameters of this camera are calibrated according to the quantity information and position information of the feature areas in the captured image; at least one second area 2 includes at least one first sub-area 21 and multiple second sub-areas 22. The first sub-area 21 has the second color, while the second sub-areas 22 have a third color different from the second color, that is, at least one second area 2 has a third color in addition to the second color. There will also be a feature area that can be identified by relying on the difference in grayscale value contrast between the at least one first sub-area 21 and the multiple second sub-areas 22 connected as a whole, which can be used for another camera with a smaller field of view. After photographing the part of the calibration board 100 including at least one first sub-area 21 and multiple second sub-areas 22, the parameters of this camera are calibrated according to the quantity information and position information of the feature areas in the captured image. The calibration board 100 of the present application has diverse functions, can be used for parameter calibration of at least two cameras with different field of view sizes, has a simple structure, is easy to manufacture and produce, can improve the efficiency of camera parameter calibration, and save the manufacturing cost of the calibration board 100 and the test cost of the camera.

[0080] Optionally, the feature area includes feature points, feature lines, feature surfaces, etc.

[0081] Optionally, the first color can be one of colors such as black, white, green, red, blue, yellow, orange, purple, gray, etc.

[0082] Optionally, the second color can be one of colors such as black, white, green, red, blue, yellow, orange, purple, gray, etc.

[0083] Optionally, the third color can be at least one of colors such as black, white, green, red, blue, yellow, orange, purple, gray, etc.

[0084] In a specific embodiment, the first color is black, the second color is white, and the third color is green. When the first color is black and the second color is white, the grayscale values of the first color and the second color differ the most, and the contrast is the most obvious. When used for camera calibration, the feature area or feature points can be recognized more accurately, making the camera parameters obtained by calibration more accurate. In this way, the first color and the second color have a large contrast, or rather, a large color difference and grayscale value difference, and the area at the color junction is easily recognized as a kind of feature; similarly, the third color and the second color also have a large contrast, or rather, a large color difference and grayscale value difference, and the area at the color junction is easily recognized as another kind of feature. Therefore, the calibration board 100 can have two levels of recognizable features and can be used for parameter calibration of two cameras with different field of views. The calibration efficiency is higher, and the calibration board 100 can be used for two purposes, saving production costs.

[0085] Please refer to Figure 1 In some embodiments, the plurality of first regions 1 and the plurality of second regions 2 are both squares, and the plurality of first regions 1 and the plurality of second regions 2 are alternately arranged and connected in sequence to form a first checkerboard.

[0086] Setting the plurality of first regions 1 and the plurality of second regions 2 as squares and alternately connecting them into a first checkerboard helps to standardize the calibration pattern of the calibration board 100. The calibration board 100 is easier to produce, and the difference in grayscale value contrast is relatively uniform, which is beneficial to better recognizing the feature area in the captured image. It is easy to recognize the corner points adjacent to two adjacent same-color squares as feature points, improving the camera parameter calibration efficiency. It can be understood that a checkerboard is a grid array in the shape of a chessboard. Generally speaking, a corner point is an extreme point, that is, a point that is particularly prominent in certain aspects, and is an isolated point or the end point of a line segment with the maximum or minimum intensity in certain attributes. For an image, it is the connection point of the object contour line. For the checkerboard of the calibration board 100, it is the points at the four corners of each grid.

[0087] Please refer to Figure 1 and Figure 2 , in some embodiments, at least one second region 2 includes a plurality of first sub-regions 21 and a plurality of second sub-regions 22. The plurality of first sub-regions 21 and the plurality of second sub-regions 22 are both squares, and the plurality of first sub-regions 21 and the plurality of second sub-regions 22 are alternately arranged and connected in sequence to form a second checkerboard, and the third color is different from the first color. In a specific embodiment, the first color is black, the second color is white, and the third color is green.

[0088] A plurality of first sub-regions 21 and a plurality of second sub-regions 22 are set as squares and are alternately connected to form a second checkerboard. That is, the first checkerboard is a large grid and the second checkerboard is a small grid. The calibration board 100 has a two-level nested checkerboard. The first checkerboard can be used for parameter calibration of a camera with a larger field of view angle, and the second checkerboard can be used for parameter calibration of a camera with a smaller field of view angle. The calibration board 100 has more diversified functions and higher calibration efficiency. The first color is different from both the third color and the second color and has a contrast difference in gray values, which can enable the camera to easily capture the feature regions brought about by the gray value difference, and can easily identify the corner points adjacent to two adjacent same-color grids as feature regions, thereby facilitating subsequent image processing and improving the camera parameter calibration efficiency.

[0089] Please refer to Figure 3 and Figure 4 , in some embodiments, at least one second region 2 includes a first sub-region 21 and a plurality of second sub-regions 22. The first sub-region 21 is connected to each second sub-region 22 as a whole, and the third color is the same as the first color. In a specific embodiment, the first color is black, the second color is white, and the third color is black. Of course, in some other embodiments, the third color may also be different from the first color.

[0090] The first sub-region 21 is connected to the plurality of second sub-regions 22 as a whole. The third color is the same as the first color and different from the second color. Therefore, a camera with a larger field of view angle can identify feature regions according to the differences between the first color and the second color of the plurality of first regions 1 and the plurality of second regions 2, and a camera with a smaller field of view angle can identify feature regions according to the differences between the second color and the third color of the first sub-region 21 and the plurality of second sub-regions 22. The calibration board 100 has more diversified functions, the subsequent image processing of the calibration board 100 captured by the camera is more convenient, and the calibration efficiency of the camera parameters is higher.

[0091] In some embodiments, the shapes of the plurality of second sub-regions 22 include at least one of a circle, a rectangle, an ellipse, a triangle, a parallelogram, a star, etc. In addition, the second sub-region 22 can also be an irregular special-shaped structure.

[0092] The plurality of second sub-regions 22 are set as one or more regular shapes, and it is easy to identify the centroid points of the second sub-regions 22 as feature points in the captured image. According to the information of these feature points, it is convenient to calibrate the camera parameters, and the calibration efficiency of the camera parameters is higher.

[0093] In a specific embodiment, the plurality of first regions 1 and the plurality of second regions 2 are both squares. The plurality of first regions 1 and the plurality of second regions 2 are alternately arranged and connected in sequence to form a checkerboard. The plurality of second sub-regions 22 are circular, the plurality of first sub-regions 21 are arranged at intervals, and the second sub-regions 22 are respectively connected to each first sub-region 21 as a whole.

[0094] For the second aspect, please refer to Figure 9 , the embodiment of the present application provides a calibration method for calibrating camera parameters, including S110 and S120:

[0095] S110, obtain a calibration image 110;

[0096] Among them, please refer to Figure 5 , Figure 6 , Figure 7 and Figure 8 , the calibration image 110 includes a plurality of first regions 1 and a plurality of second regions 2. The plurality of first regions 1 and the plurality of second regions 2 are alternately arranged and connected in sequence. The first region 1 has a first color, and the second region 2 has at least a second color; at least one second region 2 includes at least one first sub-region 21 and a plurality of second sub-regions 22. At least one first sub-region 21 and the plurality of second sub-regions 22 are connected as a whole. The first sub-region 21 has a second color, and the second sub-region 22 has a third color; wherein, the first color is different from the second color, and the second color is different from the third color. The calibration image 110 has a first feature point, and at least one second region 2 has a second feature point.

[0097] Specifically, the calibration board 100 is photographed by a camera to obtain an image of the calibration board 100, that is, the calibration image 110. Among them, the camera includes, but is not limited to, camera modules such as mobile phone cameras, vehicle-mounted cameras, security monitors, and cameras. The camera module includes an optical imaging system and a photosensitive system for photoelectric conversion. For a detailed description of the calibration board 100, please refer to the corresponding part of the above embodiment, which will not be elaborated here.

[0098] S120, when the total number of the first region 1 and the second region 2 is greater than or equal to a preset threshold, obtain the first number of the first feature points and the first coordinates of each of the first feature points, and obtain the calibration data of the camera that captures the calibration image 110 according to the first number and the first coordinates; and when the total number of the first region 1 and the second region 2 is less than the preset threshold, obtain the second number of the second feature points and the second coordinates of each of the second feature points, and obtain the calibration data of the camera that captures the calibration image 110 according to the second number and the second coordinates.

[0099] Optionally, the preset threshold may be, but is not limited to, 4, 6, 10, 30, 60, etc. The specific number of the preset threshold can be set according to the accuracy and type requirements of the camera parameters to be calibrated. The present application does not make a specific limitation.

[0100] In a specific embodiment, when the total number of the first regions 1 and the second regions 2 is greater than or equal to a preset threshold, for example, when the total number of the first regions 1 and the second regions 2 is greater than or equal to 10, obtain the first quantity of the first feature points and the first coordinates of each of the first feature points, and obtain the calibration data of the camera that captures the calibration image 110 according to the first quantity and the first coordinates; when the total number of the first regions 1 and the second regions 2 is less than 10, obtain the second quantity of the second feature points and the second coordinates of each of the second feature points, and obtain the calibration data of the camera that captures the calibration image 110 according to the second quantity and the second coordinates.

[0101] The first feature points can be, but are not limited to, corner points, centroid points, center points, etc. A corner point is a point at which a figure bulges to form a corner, a centroid point is a point at which the center of gravity of a figure is balanced, and a center point is a point located in the exact center of a figure.

[0102] The second feature points can be, but are not limited to, corner points, centroid points, center points, etc.

[0103] According to the calibration method of the present application, after obtaining the calibration image 110 of the calibration board 100, the first regions 1 with the first color and the second regions 2 with the second color in the image are alternately arranged and connected in sequence. Since the first color is different from the second color, there will be a gray value contrast between the first color and the second color. Therefore, there will be multiple first feature points that can be recognized depending on the gray value contrast in the alternately connected first regions 1 and second regions 2. When the total number of the first regions 1 and the second regions 2 is greater than or equal to the preset threshold, obtain the quantity and coordinates of these first feature points, and the parameters of a camera with a relatively large field of view angle can be calibrated according to the quantity information and position information of the first feature points; at least one second region 2 includes at least one first sub-region 21 and multiple second sub-regions 22. The first sub-region 21 has the second color, while the second sub-regions 22 have a third color different from the second color, that is, at least one second region 2 has, in addition to the second color, a third color. There will also be second feature points that can be recognized depending on the gray value contrast between the at least one first sub-region 21 and the multiple second sub-regions 22 that are connected as a whole. When the total number of the first regions 1 and the second regions 2 is less than the preset threshold, obtain the quantity and coordinates of these second feature points, and the parameters of a camera with a relatively small field of view angle can be calibrated according to the quantity information and position information of the second feature points. The calibration method of the present application has diverse functions and can be used for calibrating the parameters of at least two cameras with different field of view angles. The calibration process is simple and easy to implement, which can improve the efficiency of camera parameter calibration and save the test cost of the camera.

[0104] Please refer to Figure 10 , the embodiment of the present application provides a calibration method for calibrating camera parameters, including S210 and S220:

[0105] S210, obtain the calibration image 110;

[0106] Among them, please refer to Figure 5 , based on the calibration image 110 described in S110, in this embodiment, both the multiple first regions 1 and the multiple second regions 2 are squares, and the corner points of the first region 1 are the first feature points.

[0107] S220, when the total number of the first region 1 and the second region 2 is greater than or equal to the preset threshold, perform binarization processing on the calibration image 110, set the third color to the second color, and obtain the first quantity of the corner points of the first region 1 and the first coordinates of the corner points of each first region 1, and obtain the calibration data of the camera that captures the calibration image 110 according to the first quantity and the first coordinates; and, when the total number of the first region 1 and the second region 2 is less than the preset threshold, obtain the second quantity of the second feature points and the second coordinates of each second feature point, and obtain the calibration data of the camera that captures the calibration image 110 according to the second quantity and the second coordinates.

[0108] It should be noted that during the binarization process, for example, in the gray values defined by the image, the first color is black which is 0, the second color is white which is 255, and the third color is green which is 120. Then, make all pixels greater than 100 = 255 and all pixels less than 100 = 0; at this time, the green seen is also considered white, that is, the third color is set to the second color. The specific value range can be adjusted according to the actual color difference.

[0109] The second feature point can be but is not limited to corner points, centroid points, center points, etc.

[0110] By performing binarization processing on the calibration image 110 and setting the third color different from the second color in the image to the second color, in this way, the first sub-region 21 and the second sub-region 22 are connected as an entity without color difference, and the feature information that can be recognized is the first feature points generated by the gray value difference caused by color between the first region 1 and the second region 2, that is, the corner points of the first region 1, which can adapt to cameras with a larger field of view angle to capture enough first feature points for calibrating parameters, and the feature recognition is more accurate; it prevents the feature information of the first sub-region 21 and the multiple second sub-regions 22 from being mixed in, generating too much feature information and interfering with feature recognition, and the feature recognition is more sensitive.

[0111] Please refer to Figure 11 , this embodiment of the present application provides a calibration method for calibrating camera parameters, including S310 and S320:

[0112] S310, obtain the calibration image 110;

[0113] Among them, please refer toFigure 6 , on the basis of the calibration image 110 described in S110, in this embodiment, the multiple first sub-regions 21 and the multiple second sub-regions 22 are both squares, and the corner points of the second sub-region 22 are the second feature points.

[0114] S320. When the total number of the first region 1 and the second region 2 is greater than or equal to a preset threshold, obtain the first quantity of the first feature points and the first coordinates of each of the first feature points, and obtain the calibration data of the camera that captures the calibration image 110 according to the first quantity and the first coordinates; and when the total number of the first region 1 and the second region 2 is less than the preset threshold, perform binarization processing on the calibration image 110, set the third color to the first color, and obtain the second quantity of the corner points of the second sub-region 22 and the second coordinates of the corner points of each second sub-region 22, and obtain the calibration data of the camera that captures the calibration image 110 according to the second quantity and the second coordinates.

[0115] It should be noted that during the binarization process, for example, in the gray values defined by the image, the first color is black which is 0, the second color is white which is 255, and the third color is green which is 120. Let all pixels greater than 150 = 255 and pixels less than 150 = 0; at this time, green is considered black, that is, the third color is set to the first color. The specific value range can be adjusted according to the actual color difference.

[0116] By performing binarization processing on the calibration image 110 and setting the third color different from the second color in the image to the first color, in this way, the multiple first sub-regions 21 and the multiple second sub-regions 22 are connected as an entity with color differences. For the calibration image 110 captured by a camera with a small field of view angle, the entire picture of the object to be photographed cannot be captured, and the feature information generated due to the color difference between the first region 1 and the second region 2 is insufficient. However, the feature information contained in the multiple first sub-regions 21 and the multiple second sub-regions 22 can be obtained relatively easily, that is, the second feature points that are the corner points of the second sub-region 22. The calibration method is simple and easy to implement, and the calibration efficiency is high.

[0117] Please refer to Figure 12 , this embodiment of the present application provides a calibration method for calibrating camera parameters, including S410 and S420:

[0118] S410, obtain the calibration image 110;

[0119] Among them, please refer to Figure 5 and Figure 6, based on the calibration image 110 described in S110, in this embodiment, both the multiple first regions 1 and the multiple second regions 2 are squares, and the corner points of the first region 1 are the first feature points; both the multiple first sub-regions 21 and the multiple second sub-regions 22 are squares, and the corner points of the second sub-region 22 are the second feature points.

[0120] S420, when the total number of the first regions 1 and the second regions 2 is greater than or equal to a preset threshold, perform binarization processing on the calibration image 110, set the third color to the second color, and obtain the second quantity of the corner points of the second sub-region 22 and the second coordinates of the corner points of each second sub-region 22, and obtain the calibration data of the camera that captures the calibration image 110 according to the first quantity and the first coordinates; and when the total number of the first regions 1 and the second regions 2 is less than the preset threshold, perform binarization processing on the calibration image 110, set the third color to the first color, and obtain the second quantity of the corner points of the second sub-region 22 and the second coordinates of the corner points of each second sub-region 22, and obtain the calibration data of the camera that captures the calibration image 110 according to the second quantity and the second coordinates.

[0121] In this way, according to the size relationship between the total number of the first regions 1 and the second regions 2 and the preset threshold, it is possible to select to set the third color to the second color or the first color through binarization processing, which can generate feature points with different quantities and coordinate ranges, meet the parameter calibration requirements of cameras with different field of view angles, and the calibration is more simple and fast.

[0122] Please refer to Figure 13 , this embodiment of the present application provides a calibration method for calibrating camera parameters, including S510 and S520:

[0123] S510, obtain the calibration image 110;

[0124] Among them, please refer to Figure 7 and Figure 8 , based on the calibration image 110 described in S110, in this embodiment, the centroid point of the second sub-region 22 is the second feature point.

[0125] S520, when the total number of the first regions 1 and the second regions 2 is greater than or equal to a preset threshold, obtain the first quantity of the first feature points and the first coordinates of each first feature point, and obtain the calibration data of the camera that captures the calibration image 110 according to the first quantity and the first coordinates; and when the total number of the first regions 1 and the second regions 2 is less than the preset threshold, obtain the centroid point of each second sub-region 22, and obtain the second quantity of the centroid points and the second coordinates of each centroid point, and obtain the calibration data of the camera that captures the calibration image 110 according to the second quantity and the second coordinates.

[0126] By comparing the gray - scale value differences between the second sub - regions 22 and the first sub - region 21, multiple second sub - regions 22 are identified. For each second sub - region 22, the centroid point is found, and the centroid point of each second sub - region 22 is used as the second feature point for the parameter calibration of the camera with a smaller field of view angle. The multiple first feature points in the first region 1 and the second region 2 that can be identified by relying on the gray - scale value differences are used for the parameter calibration of the camera with a larger field of view angle. The calibration method is simple and easy to implement, and has high calibration efficiency, and can meet the calibration of cameras with different field of view angles at the same time.

[0127] Please refer to Figure 14 In this embodiment of the application, a calibration method for camera parameter calibration is provided, including S610, S611, S612, and S620:

[0128] S610, obtain the calibration image 110;

[0129] Among them, please refer to Figure 5 , the calibration image 110 in this embodiment is consistent with the description of the calibration image 110 in S110, and will not be elaborated here.

[0130] S611, obtain the total number of the first region 1 and the second region 2.

[0131] S612, compare the total number with the preset threshold.

[0132] S620, when the total number of the first region 1 and the second region 2 is greater than or equal to the preset threshold, obtain the first number of the first feature points and the first coordinates of each first feature point, and obtain the calibration data of the camera that captures the calibration image 110 according to the first number and the first coordinates; and when the total number of the first region 1 and the second region 2 is less than the preset threshold, obtain the second number of the second feature points and the second coordinates of each second feature point, and obtain the calibration data of the camera that captures the calibration image 110 according to the second number and the second coordinates.

[0133] By obtaining the total number of the first region 1 and the second region 2, it is judged whether the information captured by the image is sufficient according to the size relationship between the total number and the preset threshold; if the total number of the first region 1 and the second region 2 is greater than or equal to the preset threshold, the first feature points are sufficient for the external parameter calibration of the camera; if the total number of the first region 1 and the second region 2 is less than the preset threshold, the first feature points are not sufficient for the parameter calibration of the camera, and the second feature points need to be used for the parameter calibration of the camera. The calibration method is simple and easy to implement, and has high calibration efficiency, and can meet the calibration of cameras with different field of view angles at the same time.

[0134] Please refer to Figure 15 In the third aspect, this embodiment of the application provides a calibration device 200, which includes:

[0135] An image acquisition unit 201 is configured to acquire a calibration image 110, where the calibration image 110 includes a plurality of first regions 1 and a plurality of second regions 2. The plurality of first regions 1 and the plurality of second regions 2 are alternately arranged and connected in sequence. The first region 1 has a first color, and the second region 2 has at least a second color. At least one second region 2 includes at least one first sub-region 21 and a plurality of second sub-regions 22. The at least one first sub-region 21 and the plurality of second sub-regions 22 are connected as a whole. The first sub-region 21 has the second color, and the second sub-region 22 has a third color. Wherein, the first color is different from the second color, and the second color is different from the third color. The calibration image 110 has a first feature point, and at least one second region 2 has a second feature point;

[0136] An image processing unit 202 is configured to, when the total number of the first regions 1 and the second regions 2 is greater than or equal to a preset threshold, acquire a first number of the first feature points and first coordinates of each of the first feature points, and obtain calibration data of a camera that acquires the calibration image 110 according to the first number and the first coordinates; and, when the total number of the first regions 1 and the second regions 2 is less than the preset threshold, the image processing unit 202 is configured to acquire a second number of the second feature points and second coordinates of each of the second feature points, and obtain calibration data of a camera that acquires the calibration image 110 according to the second number and the second coordinates.

[0137] For a detailed description of the same feature parts in this embodiment as above, please refer to the detailed description of the above embodiment, which will not be repeated here.

[0138] According to the calibration device 200 of the present application, after the image acquisition unit 201 acquires the calibration image 110 of the calibration board 100, the first regions 1 with the first color and the second regions 2 with the second color are alternately arranged and connected in sequence in the image. Since the first color is different from the second color, there will be a gray value contrast between the first color and the second color. Therefore, there will be multiple first feature points that can be recognized depending on the differences in gray value contrast in the alternately connected first regions 1 and second regions 2. When the total number of the first regions 1 and the second regions 2 is greater than or equal to a preset threshold, the image processing unit 202 acquires the number and coordinates of these first feature points, and can calibrate the parameters of a camera with a relatively large field of view according to the number information and position information of the first feature points; at least one second region 2 includes at least one first sub-region 21 and multiple second sub-regions 22. The first sub-region 21 has the second color, and the second sub-regions 22 have a third color different from the second color, that is, at least one second region 2 has a third color in addition to the second color. There will also be a second feature point that can be recognized depending on the difference in gray value contrast between the at least one first sub-region 21 and the multiple second sub-regions 22 connected as a whole. When the total number of the first regions 1 and the second regions 2 is less than the preset threshold, the image processing unit 202 acquires the number and coordinates of these second feature points, and can calibrate the parameters of a camera with a relatively small field of view according to the number information and position information of the second feature points. The calibration device 200 of the present application has various functions and can be used for calibrating the parameters of at least two cameras with different field of view sizes. The calibration process is simple and easy to perform, which can improve the efficiency of camera parameter calibration and save the test cost of the camera.

[0139] In some embodiments, the corner points of the first region 1 are the first feature points, and the image processing unit 202 further includes:

[0140] A first processing subunit 2021, which is used to perform binarization processing on the calibration image 110, set the third color to the second color, and acquire the first number of the corner points of the first region 1 and the first coordinates of each corner point of the first region 1.

[0141] By performing binarization processing on the calibration image 110 by the first processing subunit 2021 and setting the third color different from the second color in the image to the second color, in this way, the first sub-region 21 and the second sub-regions 22 are connected as a whole without color difference, and the feature information that can be recognized is the first feature points generated by the gray value difference caused by the color difference between the first region 1 and the second region 2, that is, the corner points of the first region 1, which can adapt to a camera with a relatively large field of view to capture enough first feature points for calibrating parameters, and the feature recognition is more accurate; it prevents the feature information of the first sub-region 21 and the multiple second sub-regions 22 from being mixed in, generating too much feature information and interfering with feature recognition, and the feature recognition is more sensitive.

[0142] For the detailed description of the same feature parts in this embodiment as above, please refer to the detailed description of the above embodiment and will not be repeated here.

[0143] In some embodiments, the second sub-region 22 is a square grid, and the corner points of the second sub-region 22 are the second feature points. The image processing unit 202 further includes:

[0144] A second processing subunit 2022, which is configured to perform binarization processing on the calibration image 110, set the third color to the first color, and obtain the second quantity of the corner points of the second sub-region 22 and the second coordinates of the corner points of each second sub-region 22.

[0145] By performing binarization processing on the calibration image 110 by the second processing subunit 2022 and setting the third color different from the second color in the image to the first color, in this way, the multiple first sub-regions 21 and the multiple second sub-regions 22 are connected as an integral body with color differences. For the calibration image 110 captured by a camera with a small field of view angle, the entire picture of the object being photographed cannot be captured, and the feature information generated by the color difference between the first region 1 and the second region 2 is insufficient. However, it is relatively easy to obtain the feature information included in the multiple first sub-regions 21 and the multiple second sub-regions 22, that is, the second feature points that are the corner points of the second sub-region 22. The calibration method is simple and easy to implement, and the calibration efficiency is high.

[0146] For the detailed description of the same feature parts in this embodiment as above, please refer to the detailed description of the above embodiment and will not be repeated here.

[0147] In some embodiments, the centroid point of the second sub-region 22 is the second feature point. The image processing unit 202 further includes:

[0148] A third processing subunit 2023, which is configured to obtain the centroid point of each second sub-region 22, and obtain the second quantity of the centroid points and the second coordinates of each centroid point.

[0149] Through the third processing subunit 2023, the contrast difference in gray values caused by the color between the second sub-region 22 and the first sub-region 21 is used to identify the multiple second sub-regions 22, and the centroid point of each second sub-region 22 is found. The centroid point of each second sub-region 22 is used as the second feature point for parameter calibration of a camera with a small field of view angle, and the multiple first feature points that can be identified by relying on the contrast difference in gray values caused by the color between the first region 1 and the second region 2 are used for parameter calibration of a camera with a large field of view angle. The calibration method is simple and easy to implement, and the calibration efficiency is high, which can meet the calibration of cameras with different field of view angles at the same time.

[0150] For a detailed description of the same feature parts in this embodiment as above, please refer to the detailed description of the above embodiment, which will not be repeated here.

[0151] In some embodiments, the calibration device 200 further includes:

[0152] A comparison unit 203, which is configured to obtain the total quantity of the first area 1 and the second area 2, and compare the total quantity with the preset threshold.

[0153] By using the comparison unit 203 to obtain the total quantity of the first area 1 and the second area 2, it is determined whether the information captured by the image is sufficient based on the magnitude relationship between the total quantity and the preset threshold; when the total quantity of the first area 1 and the second area 2 is greater than or equal to the preset threshold, the first feature points are sufficient for the parameter calibration of the camera; when the total quantity of the first area 1 and the second area 2 is less than the preset threshold, the first feature points are not sufficient for the parameter calibration of the camera, and the second feature points are required for the parameter calibration of the camera. The calibration method is simple and easy to implement, and has high calibration efficiency, and can meet the calibration of cameras with different field of view angles at the same time.

[0154] For a detailed description of the same feature parts in this embodiment as above, please refer to the detailed description of the above embodiment, which will not be repeated here.

[0155] Please refer to Figure 16 In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores executable program codes, and the computer-executable program codes are used to cause a computer to execute the calibration method as described above.

[0156] According to the executable program codes stored in the computer-readable storage medium of the present application, the calibration method as described above can be executed to calibrate the parameters of the camera. It can be applied to various types of cameras, and the camera parameter calibration is simple and easy to implement, and has high calibration efficiency.

[0157] In a fifth aspect, an embodiment of the present application provides an electronic device 300, which includes a processor 301 and a memory 302, and the memory 302 stores program codes executable by the processor 301. When the program codes are called and executed by the processor 301, the calibration method as described above is executed.

[0158] According to the electronic device 300 of the present application, the memory 302 stores program codes executable by the processor 301 for executing the above calibration method to calibrate the parameters of the camera. It can be applied to various types of cameras, and the camera parameter calibration is simple and easy to implement, and has high calibration efficiency.

[0159] The memory 302, being a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the display module compensation method in the embodiments of the present invention. The processor 301 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions, and modules stored in the memory 302, that is, implements the calibration method in the above method embodiments.

[0160] Optionally, the memory 302 may include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, magnetic disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection can be appropriately a computer-readable medium. For example, if software is transmitted from a website, a server, or other remote sources using coaxial cables, fiber optic cables, twisted pairs, digital subscriber lines (DSLs), or wireless technologies such as infrared, radio, and microwave, then the coaxial cables, fiber optic cables, twisted pairs, DSLs, or wireless technologies such as infrared, wireless, and microwave are included in the definition of the medium.

[0161] The electronic device 300 of the present invention includes, but is not limited to, electronic devices such as computers, laptops, tablets, mobile phones, cameras, smart bracelets, smart watches, and smart glasses.

[0162] As used herein, the terms "embodiment" and "implementation" mean that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that modifications or equivalent replacements of the technical solutions of the present application should not depart from the spirit and scope of the technical solutions of the present application.

Claims

1. A calibration method for calibrating camera parameters, characterized in that Including: Obtain a calibration image, wherein the calibration image includes a plurality of first regions and a plurality of second regions, the plurality of first regions and the plurality of second regions are alternately arranged and connected in sequence, the first region has a first color, and the second region has at least a second color; at least one of the second regions includes at least one first sub-region and a plurality of second sub-regions, the at least one first sub-region and the plurality of second sub-regions are connected as a whole, the first sub-region has a second color, and the second sub-region has a third color; wherein, the first color is different from the second color, the second color is different from the third color, the calibration image has a first feature point, and at least one of the second regions has a second feature point; When the total number of the first regions and the second regions is greater than or equal to a preset threshold, obtain the first number of the first feature points and the first coordinates of each of the first feature points, and obtain the calibration data of the camera that captures the calibration image according to the first number and the first coordinates; and, when the total number of the first regions and the second regions is less than the preset threshold, obtain the second number of the second feature points and the second coordinates of each of the second feature points, and obtain the calibration data of the camera that captures the calibration image according to the second number and the second coordinates, the first number is the number of the first feature points, and the second number is the number of the second feature points.

2. The calibration method according to claim 1, wherein The plurality of first regions and the plurality of second regions are both squares, and the corner points of the first region are the first feature points. The obtaining the first number of the first feature points and the first coordinates of each of the first feature points includes: Perform binarization processing on the calibration image, set the third color to the second color, and obtain the first number of the corner points of the first region and the first coordinates of each of the corner points of the first region.

3. The calibration method according to claim 1, wherein The plurality of first sub-regions and the plurality of second sub-regions are both squares, and the corner points of the second sub-region are the second feature points. The obtaining the second number of the second feature points and the second coordinates of each of the second feature points includes: Perform binarization processing on the calibration image, set the third color to the first color, and obtain the second number of the corner points of the second sub-region and the second coordinates of each of the corner points of the second sub-region.

4. The calibration method according to claim 1, wherein The centroid point of the second sub-region is the second feature point. The obtaining the second number of the second feature points and the second coordinates of each of the second feature points includes: Obtain the centroid point of each of the second sub-regions, and obtain the second number of the centroid points and the second coordinates of each of the centroid points.

5. The calibration method according to any one of claims 1-4, characterized in that, The first feature point includes at least one of a corner point, a centroid point, and a center point on the calibration image; the second feature point includes at least one of a corner point, a centroid point, and a center point on the second region.

6. A calibration device, characterized in that, Including: An image acquisition unit for acquiring a calibration image, wherein the calibration image includes a plurality of first regions and a plurality of second regions, the plurality of first regions and the plurality of second regions are alternately arranged and connected in sequence, the first region has a first color, and the second region has at least a second color; at least one of the second regions includes at least one first sub-region and a plurality of second sub-regions, the at least one first sub-region and the plurality of second sub-regions are connected as a whole, the first sub-region has a second color, and the second sub-region has a third color; wherein, the first color is different from the second color, the second color is different from the third color, the calibration image has a first feature point, and at least one of the second regions has a second feature point; An image processing unit for, when the total number of the first regions and the second regions is greater than or equal to a preset threshold, acquiring a first number of the first feature points and a first coordinate of each of the first feature points, and obtaining calibration data of a camera that acquires the calibration image according to the first number and the first coordinate; and, when the total number of the first regions and the second regions is less than the preset threshold, the image processing unit is used to acquire a second number of the second feature points and a second coordinate of each of the second feature points, and obtain calibration data of a camera that acquires the calibration image according to the second number and the second coordinate, the first number is the number of the first feature points, and the second number is the number of the second feature points.

7. The calibration device according to claim 6, characterized in that, The corner point of the first region is the first feature point, and the image processing unit further includes: A first processing sub-unit, the first processing sub-unit is used to perform binarization processing on the calibration image, set the third color to the second color, and acquire a first number of the corner points of the first region and a first coordinate of each of the corner points of the first region.

8. The calibration device according to claim 6, characterized in that The second sub-region is a square grid, and the corner point of the second sub-region is the second feature point, and the image processing unit further includes: A second processing sub-unit, the second processing sub-unit is used to perform binarization processing on the calibration image, set the third color to the first color, and acquire a second number of the corner points of the second sub-region and a second coordinate of each of the corner points of the second sub-region.

9. The calibration device according to claim 6, wherein The centroid point of the second sub-region is the second feature point, and the image processing unit further includes: A third processing sub-unit, the third processing sub-unit is used to acquire the centroid point of each of the second sub-regions, and acquire a second number of the centroid points and a second coordinate of each of the centroid points.

10. The calibration device according to any one of claims 6-9, characterized in that, The first feature point includes at least one of a corner point, a centroid point, and a center point on the calibration image; the second feature point includes at least one of a corner point, a centroid point, and a center point on the second region.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores executable program code, and the computer-executable program code is used to cause a computer to execute the calibration method according to any one of claims 1-5.

12. An electronic device, characterized in that, Including a processor and a memory, the memory stores program code executable by the processor, and when the program code is called and executed by the processor, the calibration method according to any one of claims 1-5 is executed.

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