CN111402344A - Calibration method, calibration device and non-volatile computer-readable storage medium - Google Patents

Abstract

The application provides a calibration method. The calibration method comprises the steps of obtaining camera parameters of a camera module, wherein the camera parameters comprise a focal length of the camera module; controlling a display module to display a calibration pattern, and shooting the calibration pattern through the camera module to obtain a calibration image; and calculating the field angle of the display module according to the focal length and the distance between the plurality of calibration points identified in the calibration image. The application also discloses a calibration device and a non-volatile computer-readable storage medium. The calibration pattern is displayed by controlling the display module, the calibration pattern is shot by the camera module to obtain a calibration image, a plurality of calibration points exist in the calibration image, and the angle of view of the display module can be accurately calculated by using the focal length of the camera module and the distance between the calibration points. Therefore, the field angle of the display module can be accurately configured, and the left eye image and the right eye image which are seen by human eyes after penetrating through the display module are completely overlapped.

Description

Calibration method, calibration device, and non-volatile computer-readable storage medium

technical field

The present application relates to the fields of super-resolution imaging, lithography and data storage, and in particular, to a calibration method, a calibration device and a non-volatile computer-readable storage medium.

Background technique

With the development of display technology, the eye-mounted display (NED, ear-EyeDisplay) represented by VR/AR glasses and other devices is gradually entering people's lives because of its portability, strong immersion, and wide range of uses. Despite numerous technological achievements in the design and optimization of eye-mounted displays themselves, there is relatively little research on the measurement of eye-mounted display devices. Due to the limitations of the production process, even if the same field of view parameters are configured, the field of view of the two display modules of each VR/AR glasses is not the same, which will cause the human eye to see the left and right after passing through the display module. The eye images are not completely coincident, therefore, how to accurately detect the field of view angles of the display modules corresponding to the left and right eyes is an urgent problem to be solved.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a calibration method, a calibration device, and a non-volatile computer-readable storage medium.

The calibration method of the embodiment of the present application includes acquiring camera parameters of a camera module, where the camera parameters include the focal length of the camera module; controlling a display module to display a calibration pattern, and photographing the calibration pattern by the camera module to obtain a calibration pattern. acquiring a calibration image; and calculating a field angle of the display module according to the distance between the focal length and a plurality of calibration points identified in the calibration image.

The calibration device of the embodiment of the present application includes a display module, a camera module, and a processor; the processor is used to obtain camera parameters of the camera module, the camera parameters include the focal length of the camera module, and control the display module. The calibration pattern is displayed in the group, and the calibration pattern is photographed by the camera module to obtain a calibration image, and the display module is calculated according to the distance between the focal length and the plurality of calibration points identified in the calibration image field of view.

A non-transitory computer-readable storage medium containing computer-executable instructions, when executed by one or more processors, cause the processors to perform the calibration method. The calibration method includes acquiring camera parameters of a camera module, where the camera parameters include a focal length of the camera module; controlling a display module to display a calibration pattern, and photographing the calibration pattern through the camera module to obtain a calibration image ; and calculate the field angle of the display module according to the distance between the focal length and the plurality of calibration points identified in the calibration image.

In the calibration method, calibration device and non-volatile computer-readable storage medium of the present application, the calibration pattern is displayed by controlling the display module, and the calibration pattern is captured by the camera module to obtain the calibration image, and there are multiple calibration points in the calibration image. , the viewing angle of the display module can be accurately calculated by using the distance between the focal length of the camera module and the calibration point. Therefore, the viewing angle of the display module can be accurately configured to ensure that the left and right eye images seen by the human eye through the display module are completely coincident.

Additional aspects and advantages of the present application will be set forth, in part, from the following description, and in part will become apparent from the following description, or may be learned by practice of the present application.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

1 is a schematic flowchart of a calibration method according to some embodiments of the present application;

2 is a schematic plan view of a calibration device according to some embodiments of the present application;

3 is a schematic plan view of the calibration device of some embodiments of the present application from another perspective;

4 is a schematic plan view of a calibration pattern of some embodiments of the present application;

5 is a schematic plan view of a calibration pattern of some embodiments of the present application;

6 is a schematic plan view of a calibration image of some embodiments of the present application;

7 is a schematic plan view of a calibration image of some embodiments of the present application;

8 is a schematic flowchart of a calibration method according to some embodiments of the present application;

9 is a schematic plan view of a checkerboard image of some embodiments of the present application;

10 is a schematic plan view of a captured image obtained by capturing a checkerboard image by a camera module according to some embodiments of the present application;

11 is a schematic plan view of a captured image obtained by capturing a checkerboard image by a camera module according to some embodiments of the present application;

12 is a schematic plan view of a captured image obtained by capturing a calibration pattern with a camera module according to some embodiments of the present application;

13 is a schematic flowchart of a calibration method according to some embodiments of the present application;

14 is a schematic flowchart of a calibration method according to some embodiments of the present application;

15 is a schematic flowchart of a calibration method according to some embodiments of the present application; and

FIG. 16 is a schematic diagram of the connection between a processor and a computer-readable storage medium according to some embodiments of the present application.

Detailed ways

The embodiments of the present application will be further described below with reference to the accompanying drawings. The same or similar reference numbers refer to the same or similar elements or elements having the same or similar functions throughout the drawings. In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary, only used to explain the embodiments of the present application, and should not be construed as limitations on the present application.

Please refer to FIG. 1 to FIG. 3 , the calibration method of the embodiment of the present application includes the following steps:

011: Obtain camera parameters of the camera module 20, where the camera parameters include the focal length of the camera module 20;

012: controlling the display module 10 to display the calibration pattern, and photographing the calibration pattern through the camera module 20 to obtain a calibration image; and

013: Calculate the field of view angle of the display module 10 according to the focal length and the distance between the multiple calibration points identified in the calibration image.

In some embodiments, the calibration device 100 includes a display module 10 , a camera module 20 and a processor 30 . The processor 30 is used for acquiring camera parameters of the camera module 20, the camera parameters including the focal length of the camera module 20; controlling the display module 10 to display a calibration pattern, and photographing the calibration pattern through the camera module 20 to obtain a calibration image; and according to the focal length The field angle of the display module 10 is calculated from the distances between the multiple calibration points identified in the calibration image. That is to say, step 011 can be implemented by the processor 30 , step 012 can be implemented by the processor 30 in cooperation with the camera module 20 and the display module 10 , and step 013 can be implemented by the processor 30 .

Specifically, the camera module 20 has a design parameter when it leaves the factory. Under the circumstance that the manufacturing and assembly errors of the camera module 20 during the manufacturing process are small, the camera parameters of the camera module 20 themselves are basically consistent with the design parameters. In addition, some manufacturers will use high precision to calibrate the camera parameters again after the camera is assembled, so as to ensure the accuracy of the camera parameters after leaving the factory.

The processor 30 can obtain the camera parameters, for example, the processor 30 can be connected with the camera module 20 to obtain the camera parameters stored in the camera module 20, or the camera parameters of the camera module 20 have been stored in advance, such as a server or a local Memory, the processor 30 is connected to the server or local memory to obtain camera parameters. The camera parameters may include the focal length of the camera module 20, the horizontal angle of view, the vertical angle of view of the camera module 20, and the like. In this embodiment, it is only necessary to obtain the focal length of the camera module 20 .

After obtaining the camera parameters, the processor 30 controls the connected display module 10 to display a preset calibration pattern (as shown in FIG. 4 and FIG. 5 ), and then controls the camera module 20 to shoot the calibration pattern to obtain a calibration image (such as 6 and 7), the calibration pattern is a special pattern, and the calibration pattern has specific mark points P, which can be easily identified from the captured calibration images, and the position of the mark point P is also set in advance. set.

The processor 30 first identifies the calibration point M corresponding to the marker point P in the calibration image (as shown in FIG. 6 and FIG. 7 ), and then obtains a plurality of calibration points M (such as the calibration pattern shown in FIG. Obtain the nine calibration points M corresponding to the nine marking points P shown in Figure 6, photograph the calibration pattern shown in Figure 5, and obtain the five calibration points corresponding to the five marking points P shown in Figure 7 The distance between M), the calibration point M and the marking point P are in one-to-one correspondence.

The calibration pattern includes a plurality of marking points P, and the plurality of marking points P in the calibration pattern form a first marking edge L1 and a second marking edge L2. As shown in FIG. 4 , the plurality of marker points P include a center marker point P1 and an edge marker point P2 (ie, one center marker point P1 and eight edge marker points P2 ), and the eight edge marker points P2 enclose a second rectangle T2 , the edge marker point P2 is located at the midpoint of the vertex and the side of the second rectangle T2, the center marker point P1 is located at the center of the second rectangle T2 (ie, the intersection of the diagonals of the second rectangle T2), the length of the second rectangle T2 The side is the first marking side L1, and the short side of the second rectangle T2 is the second marking side L2. As shown in FIG. 5 , the plurality of marker points P include a center marker point P1 and an edge marker point P2 (ie, one center marker point P1 and four edge marker points P2), and the first marker edge L1 and the second marker edge L2 are respectively is the connection line between the two opposite edge mark points P2 in the X direction and the two opposite edge mark points P2 in the Y direction, and the center mark point P1 is located at the intersection of the two connection lines, wherein the X direction and the Y direction are perpendicular , the first marking side L1 and the second marking side L2 are perpendicular, the first marking side L1 is parallel to the first side length direction of the display area of the display module 10, the display area and the calibration pattern are both rectangular, wherein the first side length is the long side of the rectangular display area, and the first side length direction is the extension direction (ie, the X direction) of the first side length.

In the calibration image, a first calibration edge N1 and a second calibration edge N2 corresponding to the first marking edge L1 and the second marking edge L2 respectively formed by a plurality of calibration points M are identified. As shown in FIG. 6 , the multiple calibration points M in the calibration image include a center calibration point M1 and a plurality of edge calibration points M2 (ie, one center calibration point M1 and eight edge calibration points M2 ), and the edge calibration points M2 are surrounded by The first rectangle T1 is located at the vertex of the first rectangle T1 and the midpoint of the side of the first rectangle T1, and the center calibration point M1 is located at the center of the first rectangle T1 (that is, the intersection of the diagonals of the first rectangle T1), the first The long side of a rectangle T1 is the first calibration side N1, and the short side of the first rectangle T1 is the second calibration side N2. As shown in FIG. 7 , the plurality of calibration points M include a center calibration point M1 and an edge calibration point M2 (ie, one center calibration point M1 and four edge calibration points M2 ), and the first calibration edge N1 and the second calibration edge N2 are respectively It is the connection line between the two opposite edge calibration points M2 in the X direction and the connection line between the two opposite edge calibration points M2 in the Y direction. The center calibration point M1 is located at the intersection of the two connection lines. The first calibration edge N1 and the second The calibration edge N2 is vertical, and the first calibration edge N1 is parallel to the first side length direction (ie, the X direction) of the display area of the display module 10 .

The processor 30 can obtain the lengths of the first calibration edge N1 and the second calibration edge N2 according to the distances between the multiple calibration points M in the calibration image, and according to the lengths of the first calibration edge N1 and the second calibration edge N2 and the camera module The focal length of 20 can be calculated to obtain the viewing angle of the display module 10. The viewing angle includes the horizontal viewing angle, the vertical viewing angle and the diagonal viewing angle, wherein the diagonal viewing angle can be determined according to the horizontal viewing angle. Angle and vertical field of view are calculated, so generally only the horizontal and vertical field of view need to be calculated. It can be understood that the type of the calibration pattern includes, but is not limited to, the patterns shown in the above-mentioned Figures 4 and 5. It is only necessary to have the first marking edge L1 parallel to the X direction and the second marking edge L2 parallel to the Y direction in the calibration pattern respectively. That's it.

In the calibration method and the calibration device 100 of the present application, the display module 10 is controlled to display the calibration pattern, and the camera module 20 is used to photograph the calibration pattern to obtain a calibration image, and the calibration image has a calibration point corresponding to the mark point of the calibration pattern, The viewing angle of the display module 10 can be accurately calculated by using the distance between the focal length of the camera module 20 and the calibration point. As a result, the viewing angle of the display module 10 can be accurately configured to ensure that the left and right eye images seen by the human eye are completely coincident.

Please refer to FIG. 8 and FIG. 9, in some embodiments, step 011 includes:

0111: Control the alignment of the camera module 20 and the calibration plate 40; and

0112: controlling the camera module 20 to photograph the checkerboard pattern on the calibration plate 40; and

0113: Calculate camera parameters according to the checkerboard image obtained by shooting.

2 and 3, in some embodiments, the calibration device 100 further includes a positioning device 50, the positioning device 50 is used to control the alignment of the camera module 20 and the calibration plate 40; the processor 30 is also used to control the camera module The group 20 shoots the checkerboard pattern on the calibration board 40; and calculates the camera parameters according to the checkerboard image obtained by shooting. That is to say, step 0111 may be implemented by the positioning device 50 , and steps 0112 and 0113 may be implemented by the processor 30 .

Specifically, in order to prevent the actual parameters of the camera module 20 from being greatly deviated from the set parameters due to manufacturing and assembly errors, in order to ensure the accuracy of the acquired camera parameters, the camera parameters need to be accurately detected in advance. In order to ensure the clarity of the image captured by the camera module 20, the camera module 20 should be aligned with the calibration plate 40. Specifically, the center of the calibration plate 40 can be positioned on the optical axis O of the camera module 20 by the positioning device 50, And make the calibration plate 40 perpendicular to the optical axis O, in this way, the calibration plate 40 can be located in the center area of the field of view of the camera module 20 to the maximum extent, avoiding the distortion of the edge area of the field of view and affecting the imaging quality, and ensuring the camera module. Imaging quality of images captured by group 20.

After the positioning is completed, the calibration pattern on the calibration plate 40 can be photographed by the camera module 20 (this application takes the calibration pattern as the checkerboard pattern shown in FIG. The calibration pattern can also be other suitable patterns, which is not limited here), determine whether it is aligned, specifically, first determine whether the center point z of the checkerboard pattern is located in the center of the entire captured image S1, when the center point z of the checkerboard pattern When located on the optical axis O of the camera module 20, the center point z of the checkerboard pattern must be located in the center of the captured image S1 (as shown in FIG. 10), and when the center point z of the calibration plate 40 is not located in the light of the camera module 20. When the axis is O, the center point z of the checkerboard pattern will deviate from the center of the captured image S2 (as shown in FIG. 11 ), so that it can be accurately determined whether the center of the calibration plate 40 is located on the optical axis O of the camera module 20;

Then it can be judged whether the plane where the calibration plate 40 is located is perpendicular to the optical axis O. It can be understood that when the calibration plate 40 is perpendicular to the optical axis O, the center point z of the checkerboard pattern in the captured image S1 reaches the two long sides (parallel to the X direction). The distance between the two sides) should be the same (d1 and d2 in Figure 10), and similarly, the center point z of the checkerboard pattern in the captured image S1 to the two short sides (two sides parallel to the Y direction) ) should also be the same (d3 and d4 in Figure 10), if they are not the same, it means that the calibration plate 40 is not perpendicular to the optical axis O, and there is a certain error in the positioning angle of the calibration plate 40 (such as around the X direction or Y The rotation angle in the X direction can be corrected by the positioning device 50. For example, the rotation angle error in the X direction can be corrected according to the difference between d1 and d2, and the rotation angle error in the Y direction can be corrected according to d3 and d4. The positioning device 50 can Realize the functions of fixing the camera module 20, the calibration board 40 and the display module 10, height adjustment, three-axis angle adjustment, etc., so as to ensure the alignment of the camera module 20 of the calibration board 40, which is beneficial to improve the camera of the subsequent camera module 20. parameters and the accuracy of the viewing angle of the display module 10 .

After alignment, the processor 30 controls the camera module 20 to photograph the checkerboard pattern on the calibration board 40 to obtain a checkerboard image. According to Zhang Zhengyou's camera calibration method and the checkerboard image, the camera of the camera module 20 can be accurately detected. parameter. In other embodiments, the calibration plate 40 may not be provided, and the camera module 20 and the display module 10 only need to be aligned (that is, the center of the display area of the display module 10 is located on the optical axis O of the camera module 20, And the surface where the display module 10 is located is perpendicular to the optical axis O). Then, the display module 10 displays the checkerboard pattern, and the camera module 20 captures the checkerboard pattern displayed by the display module 10 to obtain a checkerboard image, so that the checkerboard image can be accurately detected according to Zhang Zhengyou's camera calibration method and the checkerboard image. Camera parameters of the camera module 20 . In this way, there is no need to set a calibration plate, and it is only necessary to align the display module 10 and the camera module 20 , the structure of the calibration device 100 is simpler, and the calibration process is reduced.

In the embodiment of the present application, the calibration plate 40 of the present application is located on the back side of the display module 10. It can be understood that the display module 10 of the AR device is generally light-transmitting, so that the scene behind the display module 10 can also be viewed As observed by the human eye, the combination of the virtual image and the real image is realized, and the camera module 20 can photograph the checkerboard pattern of the calibration board 40 through the display module 10 . Therefore, the positioning device 50 can align the camera module 20 , the display module 10 and the calibration plate 40 , so as to realize the calibration of the camera module 20 and the calibration of the display module 10 .

Please refer to FIG. 12 and FIG. 13. In some embodiments, the multiple calibration points M in the calibration image include a center calibration point M1 and a plurality of edge calibration points M2, and the edge calibration points M2 enclose a first rectangle T1 and are located in the first rectangle T1. The vertex of a rectangle T1 and the midpoint of the side of the first rectangle T1, the center calibration point M1 is located in the center of the first rectangle T1, the long side of the first rectangle T1 is the first calibration side N1, and the short side of the first rectangle T1 is For the second calibration edge N2, the calibration method further includes:

014: when the distances between the two first calibration sides N1 and the center calibration point M1 are equal, determine that the camera module 20 and the display module 10 are aligned in the length direction of the first side of the display area; and

015: When the distances between the two second calibration sides N2 and the center calibration point M1 are equal, determine that the camera module 20 and the display module 10 are aligned in the second side length direction of the display area, and the second side length direction is the same as the first side. The long direction is vertical.

Please refer to FIG. 3 , in some embodiments, the processor 30 is further configured to: determine that the camera module 20 and the display module 10 are in the display area when the distances between the two first calibration sides N1 and the center calibration point M1 are equal. When the distances between the two second calibration edges N2 and the center calibration point M1 are equal, it is determined that the camera module 20 and the display module 10 are aligned in the second side length direction of the display area. That is, steps 014 and 015 may be implemented by the processor 30 .

Specifically, in order to ensure the accuracy of the camera module 20 shooting the calibration pattern displayed by the display module 10, the positioning device 50 can first control the camera module 20 and the display module 10 to align, so that the captured calibration image is located in the camera module The central area of the 20-degree field of view avoids the distortion of the edge area from affecting the imaging quality of the calibration image.

When the center calibration point M1 of the first rectangle T1 (corresponding to the center marker point P1 of the calibration pattern (shown in FIG. 4 )) is located on the optical axis O of the camera module 20, the center calibration point M1 of the calibration image S3 must be located at the center of the captured image S4. In the center, the calibration image S3 is the image displayed in the display area of the display module 30. Since the field of view of the camera module 30 is generally larger than the field of view of the display module 10, not only the display area will be captured during shooting, but also Part of the area outside the display area will also be photographed, therefore, the photographed image S4 generally includes the calibration image S3. In this way, it can be accurately determined whether the center of the display module 10 (ie, the center mark point P1 of the calibration pattern) is located on the optical axis O of the camera module 20 .

The processor 30 then determines whether the surface of the display module 10 is perpendicular to the optical axis O. When the calibration plate 40 is perpendicular to the optical axis O, the surface of the display module 10 and the camera module 20 are aligned in the X and Y directions. Specifically, the distance between the two first calibration sides N1X of the first rectangle T1 and the center calibration point M1 (that is, the distance between the edge calibration point M2 and the center calibration point M1 respectively located at the midpoint of the two first calibration sides N1 ) are equal, it is determined that the camera module 20 and the display module 10 are aligned in the first side length direction of the display area, wherein the alignment in the first side length direction of the display area means that the display module 10 is not relative to the camera module 20. the rotation angle around the X direction); the distance between the two second calibration sides N2 and the center calibration point M1 in the first rectangle T1 (that is, the edge calibration point M2 and the center at the midpoint of the two second calibration sides N2 respectively) When the distance of the calibration point M2) is equal, it is determined that the camera module 20 and the display module 10 are aligned in the second side length direction of the display area, wherein the second side length is the short side of the rectangular display area, and the second side length direction is is the extension direction of the second side length (ie, the Y direction). Alignment in the second side length direction of the display area means that the display module 10 does not have a rotation angle around the Y direction relative to the camera module 20). In this way, it can be accurately determined whether the camera module 20 and the display module 10 are aligned, which is beneficial to improve the accuracy of the subsequent calculation of the viewing angle of the display module 10 . In other embodiments, the processor 30 compares the length of the first calibration edge N1 with a preset first standard length, and the first standard length is when the camera module 30 and the display module 10 are completely aligned, The camera module 30 captures the same calibration pattern displayed by the display module 10 to determine the length of the first calibration edge N1. When the length of the first calibration edge N1 is the same as the first standard length, the camera module 20 and the first standard length can be determined. The display module 10 is aligned in the Y direction. Similarly, the processor 30 compares the length of the second calibration edge N2 with a preset second standard length, and the second standard length is the distance between the camera module 30 and the display module 10. In the case of alignment, the camera module 30 shoots the same calibration pattern displayed by the display module 10 to determine the length of the second calibration edge N2. When the length of the second calibration edge N2 is the same as the second standard length, it can be Make sure that the camera module 20 and the display module 10 are aligned in the X direction.

4 and 14, in some embodiments, the calibration pattern includes a plurality of mark points P, and the plurality of mark points P in the calibration pattern form a first mark side L1 and a second mark side L2, and the first mark side L1 It is perpendicular to the second marking side L2, the first marking side L1 is parallel to the first side length direction of the display area of the display module 10, and the display area and the calibration pattern are rectangular; A calibration edge N1 and a second calibration edge N2, step 013 includes:

0131: Calculate the horizontal field of view of the display module 10 according to the ratio of the focal length, the length of the first calibration side N1, and the length of the first marker side L1 to the length of the calibration pattern; and

0132: Calculate the vertical viewing angle of the display module 10 according to the focal length, the length of the second calibration edge N2, and the ratio of the length of the second marking edge L2 to the width of the calibration pattern.

In some embodiments, the processor 30 is further configured to calculate the horizontal field of view of the display module 10 according to the focal length, the length of the first calibration edge N1, and the ratio of the length of the first marking edge L1 to the length of the calibration pattern, And calculate the vertical field angle of the display module 10 according to the focal length, the length of the second marking side N2, and the ratio of the length of the second marking side L2 to the width of the marking pattern. That is, steps 0131 and 0132 may be implemented by the processor 30 .

Specifically, the first marking edge N1 and the second marking edge N2 are shown in FIGS. 4 and 5 . According to the different calibration patterns, the first marking edge N1 and the second marking edge N2 are also different. The first marking edge N1 in FIG. 6 is also different. and the second calibration edge N2 respectively correspond to the first marking edge N1 and the second marking edge N2 of FIG. 4 , and the first marking edge N1 and the second marking edge N2 of FIG. The two flag edges N2 correspond. The horizontal field of view and vertical field of view can be obtained by the following formulas:

fw=2*atan(Dw/2*a/F), fh=2*atan(Dh/2*b/F), wherein, fw is the horizontal field of view of the display module 10, and fh is the display module 10 Dw is the length of the first calibration edge N1, Dh is the length of the second calibration edge N2, a is the ratio between the length of the first marking edge L1 and the length of the calibration pattern, and b is the second marking edge L2 The ratio of the length of F to the width of the calibration pattern, F is the focal length of the camera module 20 . In this way, the horizontal angle of view and the vertical angle of view can be quickly calculated according to the above formula.

Referring to FIG. 4 , in some embodiments, the ratio of the length of the first marking edge L1 to the length of the calibration pattern is the same as the ratio of the length of the second marking edge L2 to the width of the calibration pattern.

Specifically, the ratio of the length of the first marking edge L1 to the length of the rectangular calibration pattern is a first predetermined ratio, and the ratio of the length of the second marking edge L2 to the width of the rectangular calibration pattern is a second predetermined ratio, the first predetermined ratio and the second predetermined ratio may be the same or different. For example, as shown in FIG. 4 and FIG. 5, the first predetermined ratio and the second predetermined ratio are the same and both are 0.7; or, the first predetermined ratio and the second predetermined ratio are the same and both are 0.8; The two predetermined ratios are different and are 0.7 and 0.8, respectively.

Please refer to FIG. 3 , FIG. 6 and FIG. 15 , in some embodiments, there are two camera modules 20 and two display modules 10 , and the two camera modules 20 and the two display modules 10 are in one-to-one correspondence, and the calibration method is also include:

016: Calculate the corresponding field angle of the display module 10 according to the focal length of the camera module 20 and the distances between the plurality of calibration points M in the corresponding calibration image.

In some embodiments, the processor 30 is further configured to calculate the corresponding field angle of the display module 10 according to the focal length of the camera module 20 and the distance between the plurality of calibration points in the corresponding calibration image. That is, step 016 may be implemented by the processor 30 .

Specifically, an AR/VR device is generally provided with two display modules 10 corresponding to human eyes. During display, the two display modules 10 display the same content. After configuring the appropriate field of view parameters, the two display modules The images displayed on the retina are superimposed. When calibrating the display module 10, two camera modules 20 can be used to simulate human eyes, and the distance D between the two camera modules 20 is the distance between the human eyes. The distance corresponds to the two display modules 10 of the AR/VR device respectively, so as to calibrate the corresponding display modules 10 respectively, according to the focal length of the camera module 20 and the distance between multiple calibration points in the corresponding calibration image The field of view of the display module 10 is calculated, wherein the corresponding calibration image is obtained by the camera module 20 photographing the calibration pattern displayed by the corresponding display module 10 . Therefore, the field of view angles of the two display modules 10 are obtained respectively accurately, so as to accurately configure the display modules 10 and ensure that the images of the two display modules 10 seen by the human eye are coincident. In addition, the two display modules 10 are calibrated at the same time, and the calibration efficiency is high.

In some embodiments, the calibration points M are located at the centers of multiple circles with the same radius, and the distance between the calibration points M is the center-to-center distance between the circles where the calibration points M ( FIG. 12 ) are located.

Specifically, in order to more accurately calculate the distance between the calibration points M, multiple circles with the same radius can be used as the calibration area in the calibration pattern S3, and then the center of each circle is used as the calibration point M, thereby avoiding The influence of the size of the calibration point M itself on the distance between the calibration points M can determine the calibration point M more accurately. In the subsequent calculation, the center distance between the two calibration areas can be used as the distance between the calibration points M of the two calibration areas, so that the distance between the calibration points M can be more accurately determined, and the viewing angle of the display module 10 can be improved. Calculated accuracy of field angle.

Referring to FIG. 16 , one or more non-volatile computer-readable storage media 300 containing computer-executable instructions 302 according to an embodiment of the present application, when the computer-executable instructions 302 are executed by one or more processors 30 , make The processor 30 can execute the startup method of any of the above-mentioned embodiments.

For example, referring to FIGS. 1 to 3, when the computer-executable instructions 302 are executed by one or more processors 30, the processors 30 are caused to perform the following steps:

011: Obtain camera parameters of the camera module 20, where the camera parameters include the focal length of the camera module 20;

012: controlling the display module 10 to display the calibration pattern, and photographing the calibration pattern through the camera module 20 to obtain a calibration image; and

013: Calculate the field of view angle of the display module 10 according to the focal length and the distance between the multiple calibration points identified in the calibration image.

For another example, referring to FIG. 2, FIG. 8 and FIG. 9, when the computer-executable instructions 302 are executed by one or more processors 30, the processors 30 may further perform the following steps:

0111: Control the alignment of the camera module 20 and the calibration plate 40; and

0112: controlling the camera module 20 to photograph the checkerboard pattern on the calibration plate 40; and

0113: Calculate camera parameters according to the checkerboard image obtained by shooting.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" or the like is meant to be used in conjunction with the described embodiments. A particular feature, structure, material, or characteristic described in a manner or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Any description of a process or method in the flowcharts or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing a specified logical function or step of the process , and the scope of the preferred embodiments of the present application includes alternative implementations in which the functions may be performed out of the order shown or discussed, including performing the functions substantially concurrently or in the reverse order depending upon the functions involved, which should It is understood by those skilled in the art to which the embodiments of the present application belong.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and alterations.

Claims (17)

1. A calibration method, characterized in that the calibration method comprises:

acquiring camera parameters of a camera module, wherein the camera parameters comprise a focal length of the camera module;

controlling a display module to display a calibration pattern, and shooting the calibration pattern through the camera module to obtain a calibration image; and

and calculating the field angle of the display module according to the focal length and the distance between the plurality of calibration points identified in the calibration image.

2. The calibration method according to claim 1, wherein the acquiring the camera parameters of the camera module comprises:

controlling the camera module to align with the calibration plate;

controlling the camera module to shoot checkerboard patterns on the calibration plate; and

and calculating the camera parameters according to the shot checkerboard image.

3. The calibration method according to claim 1, wherein the display area is rectangular, the calibration pattern comprises a plurality of mark points, the plurality of mark points in the calibration pattern form a first mark edge and a second mark edge, the first mark edge and the second mark edge are perpendicular, and the first mark edge is parallel to a first edge length direction of the display area of the display module; the method for calculating the field angle of the display module according to the focal length and the distance between the plurality of calibration points identified in the calibration image comprises the following steps:

calculating the horizontal field angle of the display module according to the focal length, the length of the first calibration edge and the ratio of the length of the first mark edge to the length of the calibration pattern; and

and calculating the vertical field angle of the display module according to the focal length, the length of the second calibration edge and the ratio of the length of the second mark edge to the width of the calibration pattern.

4. The calibration method according to claim 3, wherein the calibration points in the calibration image comprise a center calibration point and a plurality of edge calibration points, the edge calibration points enclose a first rectangle and are located at the vertex of the first rectangle and the midpoint of the side of the first rectangle, the center calibration point is located at the center of the first rectangle, the long side of the first rectangle is the first calibration side, and the short side of the first rectangle is the second calibration side, the calibration method further comprising:

when the distances between the two first calibration edges and the central calibration point are equal, the camera module and the display module are determined to be aligned in the first edge length direction of the display area; and

and when the distances between the two second calibration edges and the central calibration point are equal, determining that the camera module and the display module are aligned in a second side length direction of the display area, wherein the second side length direction is perpendicular to the first side length direction.

5. The calibration method according to claim 3, wherein the calibration pattern is rectangular, the calibration pattern comprises a plurality of mark points, the plurality of mark points comprises a center mark point and a plurality of edge mark points, the edge mark points enclose a second rectangle and are located at the vertex of the second rectangle and the midpoint of the side of the second rectangle, the center mark point is located at the center of the second rectangle, the long side of the second rectangle is the first mark side, and the short side of the second rectangle is the second mark side.

6. The calibration method according to claim 3 or 5, wherein the ratio of the length of the first marker edge to the length of the calibration pattern is the same as the ratio of the length of the second marker edge to the width of the calibration pattern.

7. The calibration method according to claim 1, wherein there are two camera modules and two display modules, and the two camera modules and the two display modules correspond to each other one by one, and the calibration method further comprises:

and calculating the corresponding field angle of the display module according to the focal length of the camera module and the distance between the plurality of calibration points in the corresponding calibration image.

8. The calibration method according to claim 1, wherein the calibration points are located at the centers of a plurality of circles with the same radius, and the distance between the calibration points is the center distance between the circles where the calibration points are located.

9. A calibration device is characterized by comprising a display module, a camera module and a processor; the processor is used for acquiring camera parameters of the camera module, the camera parameters comprise a focal length of the camera module, controlling the display module to display a calibration pattern, shooting the calibration pattern through the camera module to acquire a calibration image, and calculating a field angle of the display module according to the focal length and distances between a plurality of calibration points identified in the calibration image.

10. The calibration device according to claim 9, wherein the calibration device further comprises a positioning device and a calibration plate, the positioning device is used for controlling the alignment of the camera module and the calibration plate; the processor is also used for controlling the camera module to shoot the checkerboard patterns on the calibration plate and calculating the camera parameters according to the shot checkerboard images.

11. The calibration device according to claim 9, wherein the display area is rectangular, the calibration pattern includes a plurality of mark points, the mark points in the calibration pattern form a first mark edge and a second mark edge, the first mark edge and the second mark edge are perpendicular, and the first mark edge is parallel to a first edge length direction of the display area of the display module; the processor is further configured to calculate a horizontal field angle of the display module according to the focal length, the length of the first calibration edge, and a ratio of the length of the first mark edge to the length of the calibration pattern, and calculate a vertical field angle of the display module according to the focal length, the length of the second calibration edge, and a ratio of the length of the second mark edge to the width of the calibration pattern.

12. The calibration device according to claim 11, wherein the plurality of calibration points in the calibration image include a center calibration point and a plurality of edge calibration points, the edge calibration points surround a first rectangle and are located at the vertex of the first rectangle and the midpoint of the side of the first rectangle, the center calibration point is located at the center of the first rectangle, the long side of the first rectangle is the first calibration side, the short side of the first rectangle is the second calibration side, the processor is further configured to determine that the camera module and the display module are aligned in the first side length direction of the display area when the distances between the two first calibration sides and the center calibration point are equal, and determine that the camera module and the display module are aligned in the second side length direction of the display area when the distances between the two second calibration sides and the center calibration point are equal, the second side length direction is perpendicular to the first side length direction.

13. The calibration device according to claim 11, wherein the calibration pattern is a rectangle, the calibration pattern comprises a plurality of mark points, the plurality of mark points comprises a center mark point and a plurality of edge mark points, the edge mark points enclose a second rectangle and are located at the vertex of the second rectangle and the midpoint of the side of the second rectangle, the center mark point is located at the center of the second rectangle, the long side of the second rectangle is the first mark side, and the short side of the second rectangle is the second mark side.

14. Calibration arrangement according to claim 11 or 13, wherein the ratio of the length of the first marker edge to the length of the calibration pattern is the same as the ratio of the length of the second marker edge to the width of the calibration pattern.

15. The calibration device according to claim 9, wherein the number of the camera modules and the number of the display modules are two, the two camera modules and the two display modules correspond to each other one by one, and the processor is further configured to:

and calculating the field angle of the display module according to the focal length of the camera module and the distance between the plurality of calibration points in the corresponding calibration image.

16. The calibration device according to claim 8, wherein the calibration points are located at the centers of a plurality of circles with the same radius, and the distance between the calibration points is the center distance between the circles where the calibration points are located.

17. A non-transitory computer-readable storage medium containing computer-executable instructions that, when executed by one or more processors, cause the processors to perform a calibration method as defined in any one of claims 1 to 8.

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