Camera accuracy testing method, system and host computer

Abstract

The present application provides a camera accuracy testing method, system and host computer, the method comprising: obtaining an image of a measured plane taken by a camera to be tested, the measured plane including at least two marking points, and the image including at least two marking points; determining the pixel distance between pixels corresponding to any two marking points in the image; and determining the accuracy of the camera based on the pixel distance between pixels corresponding to any two marking points in the image. The present application sets at least two marking points on the measured plane, and then determines the pixel distance between pixels corresponding to any two marking points in the image taken by the camera of the measured plane including at least two marking points, thereby being able to accurately determine the accuracy of the camera based on the pixel distance, and thus accurately test the accuracy of each camera in a three-dimensional motion capture system.

Description

Technical Field

[0001] The present application relates to the technical field of vision system accuracy testing, and in particular to a camera accuracy testing method, system, and host computer. Background Art

[0002] In recent years, 3D motion capture technology has boosted the development of film and television special effects and animation production. 3D motion capture uses a 3D motion capture system to rapidly record the movements and trajectory of a person or object, then perform time-lapse analysis or multiple playbacks to determine the 3D spatial position of the person or object.

[0003] Currently, a 3D motion capture system that implements 3D motion capture technology includes multiple cameras. The 3D motion capture system determines the 3D spatial position of a human body or object by processing images captured by multiple cameras simultaneously.

[0004] Since the accuracy of each camera will affect the accuracy of the 3D motion capture system in calculating the 3D spatial position, how to test the accuracy of each camera has become an urgent problem to be solved. Summary of the Invention

[0005] The present application provides a camera accuracy testing method, system and host computer, which can accurately test the accuracy of each camera in a three-dimensional motion capture system.

[0006] In a first aspect, a camera accuracy testing method is provided, the method comprising:

[0007] Acquire an image of a measured plane captured by a camera to be tested, where the measured plane includes at least two marking points, and the image includes at least two marking points;

[0008] Determine the pixel distance between the pixels corresponding to any two marker points in the image;

[0009] The accuracy of the camera is determined based on the pixel distance between the pixels corresponding to any two marker points in the image.

[0010] In a feasible design, the camera is placed on a pan-tilt platform. Before obtaining an image of the measured plane captured by the camera, the following steps are also included:

[0011] By controlling the movement of the pan / tilt platform, the position of the camera is adjusted so that the imaging plane of the adjusted camera is parallel to the measured plane.

[0012] In a feasible design, when the measured plane includes at least four marker points, the position of the camera is adjusted by controlling the movement of the pan / tilt platform, including:

[0013] Determine a first marking point and a second marking point on the measured plane according to the center point of the measured plane, wherein the first marking point and the second marking point are located on both sides of the center point and on a first central axis of the measured plane;

[0014] Determine, based on the first central axis, a second central axis of the measured plane that is perpendicular to the first central axis;

[0015] Determine a third marking point and a fourth marking point on the measured plane according to the center point and the second center axis, wherein the third marking point and the fourth marking point are located on both sides of the center point and on the second center axis;

[0016] Adjust the height of the camera from the ground by controlling the movement of the gimbal according to the height of the center point from the ground;

[0017] Determining expected pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point based on a resolution of the image captured by the camera;

[0018] By controlling the movement of the gimbal, the shooting angle of the camera is adjusted until the pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point in the image captured by the camera are equal to the expected pixel coordinates. The position of the camera includes the height of the camera from the ground and the angle of the camera.

[0019] In one possible design, the accuracy of the camera is determined based on the pixel distance between the pixels corresponding to any two marker points in the image, including:

[0020] Determine the predicted distance between any two marker points in three-dimensional space based on the pixel distance between the pixels corresponding to any two marker points in the image;

[0021] Determine the accuracy of the camera based on the predicted distance and actual distance between any two markers in 3D space.

[0022] In one feasible design, the predicted distance between any two marker points in three-dimensional space is determined based on the pixel distance between the pixels corresponding to any two marker points in the image, including:

[0023] The predicted distance between any two marker points in three-dimensional space is determined based on the pixel distance between the pixels corresponding to any two marker points, the horizontal distance between the camera and the measured plane in three-dimensional space, the focal length of the camera lens and the size of the pixels in the image captured by the camera.

[0024] In a feasible design, the camera captures N images of the measured plane, where N is a positive integer greater than 1, and positions of at least two marking points included in any two images of the N images meet a preset condition;

[0025] Determine the camera's accuracy based on the pixel distance between any two marker points in the image, including:

[0026] Determine the standard deviation corresponding to the N pixel distances according to the N pixel distances determined respectively from the N images;

[0027] Determine the accuracy of the camera based on the standard deviation and a preset threshold.

[0028] In a feasible design, the preconditions include:

[0029] The positions of the center points of at least two markers included in any two images of the N images are different;

[0030] or,

[0031] Any two images in the N images include at least two marking points whose positions in the images are different.

[0032] In a feasible design, before determining the pixel distance between pixels corresponding to two marker points in the image, the method further includes:

[0033] Calibrate the camera to obtain the camera's intrinsic coefficients and distortion coefficients;

[0034] The image is subjected to distortion correction according to the intrinsic parameter coefficient and the distortion coefficient, so as to determine the pixel distance between pixels corresponding to any two marking points in the image through the distortion-corrected image.

[0035] In a second aspect, a host computer is provided, which is connected to the camera to be tested and includes:

[0036] An image acquisition module is used to acquire an image of the measured plane taken by the camera and send the image to the pixel distance determination module, wherein the measured plane includes at least two marking points and the image includes at least two marking points;

[0037] A pixel distance determination module is used to determine the pixel distance between pixels corresponding to any two marked points in the image and send the pixel distance to the accuracy determination module;

[0038] The accuracy determination module is used to determine the accuracy of the camera based on the pixel distance between the pixels corresponding to any two marked points in the image.

[0039] Thirdly, a camera accuracy test host computer is provided, including:

[0040] a memory for storing program instructions;

[0041] The processor is used to call and execute program instructions in the memory to implement any example in the above-mentioned camera accuracy testing method embodiment.

[0042] In a fourth aspect, a camera accuracy testing system is provided, comprising the host computer described in the second aspect, a measured plane and a camera to be tested, wherein the measured plane is used to place at least two marking points, and the camera to be tested is used to photograph the measured plane including the at least two marking points.

[0043] The above-mentioned embodiment of the present application sets at least two marking points on the measured plane, and then uses the camera to take an image of the measured plane including the at least two marking points to determine the pixel distance between the pixels corresponding to any two marking points in the image, so that the accuracy of the camera can be accurately determined based on the pixel distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 1 is a schematic diagram of a camera accuracy testing system provided by an exemplary embodiment of the present application;

[0046] Figure 2 1 is a flowchart of a camera accuracy testing method provided by an exemplary embodiment of the present application;

[0047] Figure 3 is a schematic diagram of an image captured by a camera provided by an exemplary embodiment of the present application;

[0048] Figure 4 1 is a schematic diagram of another camera accuracy testing system provided by an exemplary embodiment of the present application;

[0049] Figure 5 This is a schematic diagram of position changes of a marking point on a measured plane provided by an exemplary embodiment of the present application;

[0050] Figure 6 This is another schematic diagram of position changes of marking points on a measured plane provided by an exemplary embodiment of the present application;

[0051] Figure 7 This is another schematic diagram of position changes of marking points on a measured plane provided by an exemplary embodiment of the present application;

[0052] Figure 8 This is a schematic diagram of a host computer structure provided by an exemplary embodiment of the present application;

[0053] Figure 9 This is another schematic diagram of the host computer structure provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0054] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. It should be noted that the embodiments and features in the embodiments of the present application may be combined with each other unless there is a conflict.

[0055] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any units and all combinations of one or more associated listed items.

[0056] The present application provides a camera accuracy test method, system and host computer. The camera accuracy test method can be applied to a host computer, which is connected to the camera to be tested, such as Figure 1 As shown, the camera is located opposite the measured plane and can capture images of the measured plane. The measured plane includes at least two marking points. The marking points can be highly reflective spheres set at both ends of a T-shaped rod, or highly reflective circular surfaces. Of course, the marking points can also be in other forms, which is not limited by this application.

[0057] In this application, the camera to be tested shoots the measured plane including at least two marking points, and the host computer receives the measured plane including at least two marking points shot by the camera to be tested, and determines the accuracy of the camera based on it to realize the test of the camera.

[0058] Figure 2 FIG. 1 is a flow chart of a camera accuracy testing method provided by an exemplary embodiment of the present application. Figure 2 As shown, the camera accuracy testing method provided in the embodiment of the present application includes the following steps:

[0059] S110 , obtaining an image of a measured plane captured by a camera to be tested, where the measured plane includes at least two marking points, and the image includes at least two marking points.

[0060] In the embodiment of the present application, the connection between the host computer to which the camera accuracy testing method is applied and the camera to be tested can be achieved via a wireless network or a wired connection. After the camera captures an image of the measured surface, the image can be transmitted to the host computer via this connection, so that the host computer can obtain the image of the measured surface captured by the camera.

[0061] S120: Determine the pixel distance between pixels corresponding to any two marked points in the image.

[0062] In a feasible design, when determining the pixel distance between the pixels corresponding to any two marker points in the image, the pixel coordinates (x1, y1) and (x2, y2) corresponding to the center positions of any two marker points in the image can be determined respectively. Then, the pixel distance width (in pixels) between the pixels corresponding to the two marker points is calculated using the following formula (1):

[0063]

[0064] S130 , determining the accuracy of the camera according to the pixel distance between pixels corresponding to any two marking points in the image.

[0065] In this application, the host computer can determine the accuracy of the camera based on the pixel distance between the pixels corresponding to any two marked points in the image to implement the test of the camera.

[0066] Furthermore, after determining the accuracy of the camera, a high-precision camera can be selected to build a three-dimensional motion capture system through the high-precision camera, thereby improving the accuracy of calculating the three-dimensional spatial position.

[0067] In the embodiment of the present application, when the imaging plane of the camera is generally parallel to the plane being measured, the plane being measured captured by the camera is clearer. In addition, the host computer generally determines the accuracy of the camera based on the relationship between the pixel distance between the markers and the predicted distance of the markers in three-dimensional space. If the imaging plane of the camera is parallel to the plane being measured, it is convenient to obtain the predicted distance in three-dimensional space based on the pixel distance between the markers on the image, thereby improving the efficiency of determining the accuracy of the camera. Therefore, before obtaining the image captured by the camera of the plane being measured, the position of the camera can be adjusted so that the imaging plane of the adjusted camera is parallel to the plane being measured.

[0068] The camera's imaging plane is typically parallel to the plane being measured. This means that the line connecting two markers on the imaging plane is parallel to the line connecting two corresponding markers on the plane being measured. Furthermore, adjusting the camera's position typically involves adjusting the camera's height from the ground and its shooting angle.

[0069] In a feasible design, the position of the camera can be adjusted manually.

[0070] In another possible design, such as Figure 1 As shown, the host computer is also connected to the pan-tilt platform on which the camera is placed, and the movement of the pan-tilt platform can be controlled by the host computer. In this case, before obtaining the image of the measured plane taken by the camera, the method further includes:

[0071] By controlling the movement of the pan / tilt platform, the position of the camera is adjusted so that the imaging plane of the adjusted camera is parallel to the measured plane.

[0072] In the above example, the host computer controls the movement of the gimbal through interaction with the gimbal, thereby accurately adjusting the position of the camera and improving the degree of automation of camera position adjustment.

[0073] Of course, the movement of the pan-tilt platform can also be controlled in other ways. This application does not limit the method of controlling the movement of the pan-tilt platform.

[0074] The following describes how to precisely adjust the camera position. When the measured plane has at least four markers, the camera position is adjusted by controlling the movement of the gimbal, including:

[0075] Determine a first marking point and a second marking point on the measured plane according to the center point of the measured plane, wherein the first marking point and the second marking point are located on both sides of the center point and on a first central axis of the measured plane;

[0076] Determine, based on the first central axis, a second central axis of the measured plane that is perpendicular to the first central axis;

[0077] Determine a third marking point and a fourth marking point on the measured plane according to the center point and the second center axis, wherein the third marking point and the fourth marking point are located on both sides of the center point and on the second center axis;

[0078] According to the height of the center point from the ground, the height of the camera from the ground is adjusted by controlling the movement of the pan-tilt platform; in this step, the height of the camera from the ground is usually adjusted to be equal to the height of the center point from the ground by controlling the movement of the pan-tilt platform.

[0079] Determining expected pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point based on a resolution of the image captured by the camera;

[0080] The shooting angle of the camera is adjusted by controlling the movement of the pan / tilt platform until the pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point in the image captured by the camera are equal to the expected pixel coordinates.

[0081] When the measured plane and the imaging plane of the camera are parallel, and the center positions of the camera and the measured plane are at the same height, if the viewfinder of the camera when shooting the image coincides with the outer frame of the measured plane, then the center of the image shot by the camera and the two mutually perpendicular central axes of the image coincide with the center of the measured plane shown in the image and the two mutually perpendicular central axes of the measured plane respectively. Figure 3 As shown, if the resolution of the image is (w*h), the two mutually perpendicular central axes of the measured plane displayed in the image are respectively located at x=1 / 2*w and y=1 / 2*h (i.e., the expected pixel coordinates). Therefore, in the above embodiment, the height of the camera from the ground is determined by the height of the center point from the ground, so that the center position of the camera and the measured plane can be at the same height. Then, by setting the first marking point and the second marking point on both sides of the center point and on the first central axis of the measured plane, the third marking point and the fourth marking point are set on both sides of the center point and on the second central axis of the measured plane. Then, when the viewfinder of the image taken by the camera coincides with the outer frame of the measured plane, the position of the camera can be adjusted by controlling the movement of the pan / tilt head until the pixel coordinates of the first marking point, the second marking point, the third marking point and the fourth marking point in the image taken by the camera are respectively the corresponding expected coordinates, so that the measured plane and the imaging plane of the camera can be made parallel, so as to improve the accuracy of the camera precision obtained subsequently.

[0082] In order to improve the efficiency of adjusting the camera position, the pixel coordinates of the first marker point, the second marker point, the third marker point and the fourth marker point in the image captured by the camera can be adjusted to the expected pixel coordinates more quickly. Before determining the first marker point, the second marker point, the third marker point and the fourth marker point on the measured plane, the measured plane and the pan-tilt head can also be adjusted using a vertical level so that the measured plane is placed perpendicular to the ground, and the pan-tilt head is adjusted to be perpendicular to the ground.

[0083] For example Figure 4 As shown, after determining the center point, a first marker is set on the first central axis at a distance L1 from the center point, and a second marker is set at a distance L2 from the center point, where L1 = L2. A third marker is set on the second central axis at a distance H1 from the center point, and a fourth marker is set at a distance H2 from the center point, where H1 = H2. Based on the height H3 of the center point from the ground, the height H4 of the camera from the ground is determined, where H4 = H3. Taking a camera resolution of 4096*3072 as an example, adjust the pixel coordinates y of the first marker to 1536 and the pixel coordinates y of the second marker to 1536. Adjust the pixel coordinates x of the third marker to 2048 and the pixel coordinates x of the fourth marker to 2048 to make the measured plane parallel to the camera's imaging plane.

[0084] In one possible design, the accuracy of the camera is determined based on the pixel distance between the pixels corresponding to any two marker points in the image, including:

[0085] Determine the predicted distance between any two marker points in the three-dimensional space based on the pixel distance between the pixels corresponding to the two marker points in the image;

[0086] Determine the accuracy of the camera based on the predicted distance and actual distance between any two markers in 3D space.

[0087] For example, the method of determining the accuracy of the camera based on the predicted distance and the actual distance between any two marker points in three-dimensional space includes:

[0088] Determine the difference between the predicted distance and the actual distance between two markers in 3D space and use this difference as the accuracy of the camera.

[0089] In the above example, the difference between the predicted distance and the actual distance between any two marker points in three-dimensional space is used as the camera accuracy, which simplifies the steps of calculating the camera accuracy and improves the efficiency of calculating the camera accuracy.

[0090] In one feasible design, the predicted distance between any two marker points in three-dimensional space is determined based on the pixel distance between the pixels corresponding to any two marker points in the image, including:

[0091] The predicted distance between any two marker points in three-dimensional space is determined based on the pixel distance between the pixels corresponding to any two marker points, the horizontal distance between the camera and the measured plane in three-dimensional space, the focal length of the camera lens and the size of the pixels in the image captured by the camera.

[0092] For example, the predicted distance s1 between any two marked points in three-dimensional space is determined by the following formula (2):

[0093] s1=width* PixelWidth*WD / lens*1000 Formula (2)

[0094] Where width represents the pixel distance between the pixels corresponding to the two markers, that is, the number of pixels between the two markers. PixelWidth represents the size of the pixel in the row direction, in micrometers (μm). WD represents the vertical distance between the camera imaging plane and the measured plane, in millimeters (mm). Lens represents the focal length of the camera lens, in millimeters (mm).

[0095] In the above example, based on the pixel distance between the pixels corresponding to any two marker points, the horizontal distance between the camera and the measured plane in three-dimensional space, the focal length of the camera lens, and the size of the pixels in the image captured by the camera, the predicted distance between any two marker points in three-dimensional space can be accurately determined. Therefore, combined with the actual distance between the two marker points in three-dimensional space, the accuracy of the camera can be accurately determined.

[0096] In a feasible design, the camera captures N images of the measured plane, where N is a positive integer greater than 1, and positions of at least two marking points included in any two images of the N images meet a preset condition;

[0097] The camera's accuracy can be determined based on the pixel distance between any two markers in the image:

[0098] Determine the standard deviation corresponding to the N pixel distances according to the N pixel distances determined respectively from the N images;

[0099] Determine the accuracy of the camera based on the standard deviation and a preset threshold.

[0100] The size of the preset threshold is set as needed and is not limited in this application.

[0101] In the above example, the accuracy of the camera can be accurately determined by the standard deviation corresponding to the N pixel distances and the preset threshold.

[0102] In a feasible design, the preconditions include:

[0103] The positions of the center points of at least two markers included in any two images of the N images are different;

[0104] or,

[0105] The positions of at least two marking points included in any two images of the N images are different.

[0106] In the above example, if the positions of the centers of at least two markers included in any two images of N images are different, the positions of the centers of the two markers are changed N times so that the two markers can be located in N different fields of view in the camera lens (see Field of view area). Figure 5 Therefore, the standard deviation of the pixel distance between two markers in different fields of view in N images can comprehensively and accurately evaluate the accuracy of the camera.

[0107] For example, when the positions of the center points of at least two marking points included in any two images among N images are different, the line connecting the two marking points included in each image may be parallel to the line connecting the two marking points included in other images, or may not be parallel to the line connecting the two marking points included in other images, and this application does not limit this. Figure 5 As shown, the line connecting the two marking points in the field of view area 2 is parallel to the line connecting the two marking points in the field of view area 3, and the line connecting the two marking points in the field of view area 2 is not parallel to the line connecting the two marking points in the field of view area 5.

[0108] Exemplarily, the standard deviation σ corresponding to the N pixel distances is determined by the following formula (3):

[0109]

[0110] Where μ is the average value of the distances of N pixels.

[0111] For example, Figure 6 As shown, if the center points of at least two markers included in any two of N images differ, the position of one marker in each image remains unchanged, while the position of the other marker changes. Since the field of view of the camera lens remains unchanged for the two markers, the accuracy of the camera lens in that field of view can be accurately determined based on the N pixel distances determined for each of the N images.

[0112] In the case where the positions of at least two marking points included in any two images of N images are different in the images, it can be regarded as fixing the position of the center point of the two marking points and rotating the two marking points around the center point N times (such as Figure 7 As shown in the figure, N images are obtained. Since the center point of the two markers remains unchanged in each image, the field of view of the two markers in the camera lens remains unchanged. Based on the N pixel distances determined for each of the N images, the accuracy of the camera lens in this field of view can be accurately determined.

[0113] Due to inherent characteristics of a lens, an image captured by a camera equipped with a lens may have varying degrees of deformation and distortion in different areas. To address this issue, before determining the pixel distance between pixels corresponding to two marker points in the image, the method further includes:

[0114] Calibrate the camera to obtain the camera's intrinsic coefficients and distortion coefficients;

[0115] The image is corrected for distortion based on the intrinsic parameter coefficient and distortion coefficient.

[0116] In this case, in subsequent operations, the distortion-corrected image is used. For example, the pixel distance between pixels corresponding to two marker points in the image can be determined using the distortion-corrected image.

[0117] In the above example, distortion correction is performed on the image captured by the camera to make the image more accurate, so that the pixel distance between the pixels corresponding to two marking points in the image can be accurately determined.

[0118] The above-mentioned embodiment of the present application sets at least two marking points on the measured plane, and then uses the camera to take an image of the measured plane including the at least two marking points to determine the pixel distance between the pixels corresponding to the two marking points in the image, so that the accuracy of the camera can be accurately determined based on the pixel distance.

[0119] In combination with the above-mentioned camera accuracy test method, the present application also provides a host computer, which is connected to the camera to be tested, such as Figure 8 As shown, the host computer includes:

[0120] An image acquisition module is used to acquire an image of the measured plane taken by the camera and send the image to the pixel distance determination module, wherein the measured plane includes at least two marking points and the image includes at least two marking points;

[0121] A pixel distance determination module is used to determine the pixel distance between pixels corresponding to any two marked points in the image and send the pixel distance to the accuracy determination module;

[0122] The accuracy determination module is used to determine the accuracy of the camera based on the pixel distance between the pixels corresponding to any two marked points in the image.

[0123] In a feasible design, the host computer is also connected to the pan / tilt platform on which the camera is placed, and the host computer includes:

[0124] The camera position adjustment module is used to adjust the position of the camera by controlling the movement of the pan / tilt platform so that the imaging plane of the adjusted camera is parallel to the measured plane.

[0125] In a feasible design, when the measured plane includes at least four marker points, the camera position adjustment module adjusts the camera position by controlling the movement of the pan / tilt platform in the following manner:

[0126] Determine a first marking point and a second marking point on the measured plane according to the center point of the measured plane, wherein the first marking point and the second marking point are located on both sides of the center point and on a first central axis of the measured plane;

[0127] Determine, based on the first central axis, a second central axis of the measured plane that is perpendicular to the first central axis;

[0128] Determine a third marking point and a fourth marking point on the measured plane according to the center point and the second center axis, wherein the third marking point and the fourth marking point are located on both sides of the center point and on the second center axis;

[0129] According to the height of the center point from the ground, the height of the camera from the ground is adjusted by controlling the movement of the pan / tilt platform;

[0130] Determining expected pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point based on a resolution of the image captured by the camera;

[0131] By controlling the movement of the gimbal, the shooting angle of the camera is adjusted until the pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point in the image captured by the camera are equal to the expected pixel coordinates. The position of the camera includes the height of the camera from the ground and the angle of the camera.

[0132] In one feasible design, the accuracy determination module determines the accuracy of the camera based on the pixel distance between the pixels corresponding to any two marker points in the image in the following manner:

[0133] Determine the predicted distance between any two marker points in the three-dimensional space based on the pixel distance between the pixels corresponding to the two marker points in the image;

[0134] Determine the accuracy of the camera based on the predicted distance and actual distance between any two markers in 3D space.

[0135] In one feasible design, the accuracy determination module determines the predicted distance between any two marker points in the three-dimensional space based on the pixel distance between the pixels corresponding to any two marker points in the image by:

[0136] The predicted distance between any two marker points in three-dimensional space is determined based on the pixel distance between the pixels corresponding to any two marker points, the horizontal distance between the camera and the measured plane in three-dimensional space, the focal length of the camera lens and the size of the pixels in the image captured by the camera.

[0137] In a feasible design, the camera captures N images of the measured plane, where N is a positive integer greater than 1, and positions of at least two marking points included in any two images of the N images meet a preset condition;

[0138] Determine the camera's accuracy based on the pixel distance between any two marker points in the image, including:

[0139] Determine the standard deviation corresponding to the N pixel distances according to the N pixel distances determined respectively from the N images;

[0140] Determine the accuracy of the camera based on the standard deviation and a preset threshold.

[0141] In a feasible design, the preconditions include:

[0142] The positions of the center points of at least two markers included in any two images of the N images are different;

[0143] or,

[0144] Any two images in the N images include at least two marking points whose positions in the images are different.

[0145] In a feasible design, the device further includes:

[0146] Distortion correction module, used to calibrate the camera and obtain the camera's intrinsic parameter coefficients and distortion coefficients;

[0147] The distortion correction module is further used to perform distortion correction on the image according to the intrinsic parameter coefficient and the distortion coefficient, so as to determine the pixel distance between pixels corresponding to any two marked points in the image through the distortion-corrected image.

[0148] For other implementation methods and effects of the host computer, please refer to the description of the camera accuracy test method and will not be repeated here.

[0149] In combination with the above-mentioned camera accuracy test method, this application provides a camera accuracy test host computer, such as Figure 9 As shown, the host computer includes:

[0150] a memory for storing program instructions;

[0151] The processor is used to call and execute program instructions in the memory to implement the method in any example of the above-mentioned camera accuracy testing method embodiment.

[0152] For other implementation methods and effects of the host computer, please refer to the description of the camera accuracy test method and will not be repeated here.

[0153] In combination with the above-mentioned camera accuracy testing method, this application provides a camera accuracy testing system, such as Figure 1 As shown, the system includes the host computer in the above embodiment, a measured plane and a camera to be tested, wherein the measured plane is used to place at least two marking points, and the camera to be tested is used to shoot the measured plane including the at least two marking points.

[0154] For other implementation methods and effects of this system, please refer to the description of the camera accuracy test method and will not be repeated here.

[0155] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0156] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the flowcharts of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0157] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0158] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0159] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0160] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A camera accuracy testing method, characterized in that: The method comprises: Acquire an image of a measured plane captured by a camera to be tested, wherein the measured plane includes at least two marking points, and the image includes at least two of the marking points; Determine the pixel distance between pixels corresponding to any two of the marking points in the image; Determining the accuracy of the camera based on a pixel distance between pixels corresponding to any two of the marking points in the image, wherein determining the accuracy of the camera based on the pixel distance between pixels corresponding to any two of the marking points in the image includes: Determining a predicted distance between any two of the marking points in three-dimensional space based on a pixel distance between pixels corresponding to any two of the marking points, a horizontal distance between the camera and the measured plane in three-dimensional space, a focal length of the camera lens, and a size of pixels in an image captured by the camera; The accuracy of the camera is determined based on the predicted distance and the actual distance between any two of the marking points in three-dimensional space.

2. The method according to claim 1, characterized in that The camera is placed on a pan-tilt platform, and before obtaining the image of the measured plane taken by the camera, the method further includes: The position of the camera is adjusted by controlling the movement of the pan / tilt platform so that the imaging plane of the camera after adjustment is parallel to the measured plane.

3. The method according to claim 2, characterized in that When the measured plane includes at least four marking points, adjusting the position of the camera by controlling the movement of the pan / tilt platform includes: Determine, according to the center point of the measured plane, a first marking point and a second marking point on the measured plane, wherein the first marking point and the second marking point are located on both sides of the center point and on a first central axis of the measured plane; Determine, based on the first central axis, a second central axis of the measured plane that is perpendicular to the first central axis; Determine a third marking point and a fourth marking point on the measured plane according to the center point and the second center axis, wherein the third marking point and the fourth marking point are located on both sides of the center point and on the second center axis; According to the height of the center point from the ground, the height of the camera from the ground is adjusted by controlling the movement of the pan / tilt platform; determining expected pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point according to a resolution of the image captured by the camera; By controlling the movement of the gimbal, the shooting angle of the camera is adjusted until the pixel coordinates of the first marker point, the second marker point, the third marker point, and the fourth marker point in the image captured by the camera are respectively equal to the expected pixel coordinates, and the position of the camera includes the height of the camera from the ground and the angle of the camera.

4. The method according to any one of claims 1 to 3, characterized in that Before determining the pixel distance between pixels corresponding to the two marking points in the image, the method further includes: Calibrate the camera to obtain the intrinsic parameter coefficient and distortion coefficient of the camera; Distortion correction is performed on the image according to the intrinsic parameter coefficient and the distortion coefficient, so as to determine the pixel distance between pixels corresponding to any two marking points in the image through the distortion-corrected image.

5. A host computer connected to a camera to be tested, characterized in that: The host computer includes: An image acquisition module, configured to acquire an image of the measured plane taken by the camera and send the image to the pixel distance determination module, wherein the measured plane includes at least two marking points and the image includes at least two of the marking points; The pixel distance determination module is configured to determine the pixel distance between pixels corresponding to any two of the marking points in the image, and send the pixel distance to the accuracy determination module; an accuracy determination module, configured to determine the accuracy of the camera based on a pixel distance between pixels corresponding to any two of the marking points in the image, wherein determining the accuracy of the camera based on the pixel distance between pixels corresponding to any two of the marking points in the image comprises: Determining a predicted distance between any two of the marking points in three-dimensional space based on a pixel distance between pixels corresponding to any two of the marking points, a horizontal distance between the camera and the measured plane in three-dimensional space, a focal length of the camera lens, and a size of pixels in an image captured by the camera; The accuracy of the camera is determined based on the predicted distance and the actual distance between any two of the marking points in three-dimensional space.

6. A camera accuracy testing system, characterized in that: It comprises the host computer according to claim 5, a measured plane and a camera to be tested, wherein the measured plane is used to place at least two marking points, and the camera to be tested is used to photograph the measured plane including the at least two marking points.

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