Camera intrinsic parameter calibration device, method, system and storage medium

Abstract

The application discloses a camera internal parameter calibration device, method and system and a storage medium, wherein the camera internal parameter calibration device comprises a backlight source and five plane calibration boards, and the five plane calibration boards form a cuboid without a bottom; wherein the plane calibration board is made of plane glass, and the plane glass is provided with a transmission chessboard calibration graph; the backlight source is fixed on the back of the five plane calibration boards, and the backlight source is used for providing a transmission light source for the transmission chessboard calibration graph. The camera internal parameter calibration device and the camera internal parameter calibration method provided by the application can realize internal parameter calibration of an HFOV60°-HFOV200° camera without changing the size, pattern and placement position of the calibration graph, saving the production cost, and the calibration accuracy of the middle and edges of the camera is consistent.

Description

Technical Field

[0001] This application relates to the field of camera calibration technology, and in particular to a camera intrinsic parameter calibration device, method, system and storage medium. Background Technology

[0002] As devices that can record images, cameras play an indispensable role in people's lives. After leaving the factory, cameras need to undergo external and internal parameter calibration to minimize image distortion.

[0003] Traditional camera intrinsic parameter calibration uses a planar black and white checkerboard calibration chart, with the pattern of the calibration chart customized by each manufacturer. However, this calibration method is not flexible. For example, cameras with a small field of view require a smaller calibration chart, but it needs to be placed at a greater distance; fisheye lenses have a larger field of view, typically requiring a 2m*3m calibration chart, resulting in higher space occupancy and cost. Furthermore, different field of view requirements for intrinsic parameter calibration accuracy vary. For instance, lenses with a small field of view only need one plane for calibration; however, fisheye lenses have significant distortion, with good imaging in the central area but severe distortion at the edges, making it difficult to achieve the same calibration accuracy in the center and edges during algorithm execution.

[0004] Therefore, how to achieve the same calibration accuracy at the edges and center of a camera while maintaining low cost and high flexibility is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The main objective of this invention is to provide a camera intrinsic parameter calibration device, method, system, and storage medium, aiming to solve the problems of high cost, poor flexibility, and inconsistent calibration accuracy between camera edges and the center in existing camera intrinsic parameter calibration methods.

[0006] To achieve the above objectives, the present invention provides a camera intrinsic parameter calibration device, comprising: a backlight, five planar calibration plates, and the five planar calibration plates forming a bottomless cuboid; wherein,

[0007] The planar calibration plate is made of planar glass, and the planar glass has a transmissive chessboard calibration pattern.

[0008] The backlight is fixed to the back of the five planar calibration plates, and the backlight is used to provide a transmitted light source for the transmissive chessboard calibration map.

[0009] Optionally, the transmissive chessboard calibration map includes multiple chessboard grid units;

[0010] The chessboard grid unit includes a central rectangle and four edge rectangles respectively located at the upper left, lower left, upper right, and lower right vertices of the central rectangle, and each of the four edge rectangles has one vertex that coincides with one of the four vertices of the central rectangle.

[0011] Optionally, the central rectangle may also contain a QR code, which is used to store the coordinates of the four vertices of the central rectangle.

[0012] Furthermore, to achieve the above objectives, the present invention also provides a camera intrinsic parameter calibration method, wherein the camera intrinsic parameter calibration method is applied to the aforementioned camera intrinsic parameter calibration device, and the camera intrinsic parameter calibration method includes:

[0013] The camera to be calibrated is moved to the center position of the camera intrinsic parameter calibration device by a preset sliding device;

[0014] Control the camera located at the center position to capture multiple calibration images;

[0015] The camera's intrinsic parameters are calibrated based on multiple calibration images.

[0016] Optionally, the camera intrinsic parameter calibration method further includes:

[0017] Obtain the rotation angle of the camera during calibration;

[0018] The step of controlling the camera located at the center position to capture multiple calibration images includes:

[0019] The camera, positioned at the center, is controlled to capture multiple calibration images according to the rotation angle.

[0020] Optionally, the step of calibrating the intrinsic parameters of the camera based on multiple calibration images includes:

[0021] Coordinate information extraction processing is performed on multiple calibration images to obtain calibration image coordinate information;

[0022] The camera's intrinsic parameters are calibrated based on the calibration image coordinate information.

[0023] Optionally, the step of calibrating the intrinsic parameters of the camera based on the calibration image coordinate information includes:

[0024] The distortion coefficient and optical center of the camera are obtained based on the calibration image coordinate information to complete the intrinsic parameter calibration of the camera.

[0025] Optionally, the center position includes: a bottom center position and a vertical center position, and the step of moving the camera to be calibrated to the center position of the camera intrinsic parameter calibration device using a preset sliding device includes:

[0026] The camera to be calibrated is moved to the bottom center position of the camera intrinsic parameter calibration device by a preset sliding device;

[0027] The camera, which is located at the bottom center position, is moved to the vertical center position of the camera intrinsic parameter calibration device by means of the sliding device.

[0028] Furthermore, to achieve the above objectives, the present invention also provides a camera intrinsic parameter calibration system, the camera intrinsic parameter calibration system comprising:

[0029] The position movement module is used to move the camera to be calibrated to the center position of the camera intrinsic parameter calibration device via a preset sliding device;

[0030] An image capturing module is used to control the camera located at the center position to capture multiple calibration images;

[0031] The intrinsic parameter calibration module is used to calibrate the intrinsic parameters of the camera based on multiple calibration images.

[0032] In addition, to achieve the above objectives, the present invention also provides a storage medium storing a camera intrinsic parameter calibration program, wherein when the camera intrinsic parameter calibration program is executed, the steps of the camera intrinsic parameter calibration method described above are implemented.

[0033] This invention provides a camera intrinsic parameter calibration device, method, system, and storage medium. The camera intrinsic parameter calibration device includes: a backlight source, five planar calibration plates, and the five planar calibration plates forming a bottomless cuboid; wherein, the planar calibration plates are made of planar glass, and the planar glass has a transmissive chessboard calibration pattern; the backlight source is fixed to the back of the five planar calibration plates, and the backlight source is used to provide a transmissive light source for the transmissive chessboard calibration pattern.

[0034] The camera intrinsic parameter calibration device proposed in this invention includes a backlight and five planar calibration plates, which together form a bottomless cuboid. That is, the camera intrinsic parameter calibration device is not closed. The planar calibration plates are made of planar glass, on which a transmissive checkerboard calibration pattern is also provided. The backlight is fixed to the back of the five planar calibration plates and is used to provide a transmissive light source for the transmissive checkerboard calibration pattern so that the camera can capture images.

[0035] Compared to the traditional method of using a planar black and white checkerboard calibration chart, this invention uses a three-dimensional, five-sided transmissive checkerboard camera intrinsic parameter calibration device to calibrate the intrinsic parameters of ordinary cameras and fisheye cameras. This not only reduces the production cost of camera intrinsic parameter calibration devices, but also allows for the simultaneous calibration of intrinsic parameters of ordinary cameras and fisheye cameras, achieving the calibration objective of having the same calibration accuracy at the edges and center of the camera. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of an embodiment of the camera intrinsic parameter calibration device of the present invention;

[0039] Figure 2 This is a schematic diagram of a planar calibration plate according to an embodiment of the camera intrinsic parameter calibration device of the present invention;

[0040] Figure 3 This is a side view of a planar calibration plate according to an embodiment of the camera intrinsic parameter calibration device of the present invention;

[0041] Figure 4 This is a schematic diagram of a checkerboard unit of an embodiment of the camera intrinsic parameter calibration device of the present invention;

[0042] Figure 5 This is a schematic diagram of a transmissive chessboard calibration method according to an embodiment of the camera intrinsic parameter calibration device of the present invention.

[0043] Figure 6 A calibration diagram for a traditional planar black and white checkerboard;

[0044] Figure 7 A calibration diagram for a traditional planar chessboard grid.

[0045] Figure 8 This is a schematic diagram of the implementation process of the first embodiment of the camera intrinsic parameter calibration method of the present invention;

[0046] Figure 9 This is a schematic diagram of a three-axis slide table according to an embodiment of the camera intrinsic parameter calibration method of the present invention;

[0047] Figure 10The figure shows a fisheye lens imaging schematic diagram of an embodiment of the camera intrinsic parameter calibration method of the present invention;

[0048] Figure 11 This is a functional block diagram of an embodiment of the camera intrinsic parameter calibration system of the present invention.

[0049] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0050] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0054] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a camera intrinsic parameter calibration device according to an embodiment of the present invention. Figure 1 In the diagram, numbers 1 to 5 represent one planar calibration plate. This camera intrinsic parameter calibration device includes: a backlight, five planar calibration plates, and the five planar calibration plates forming a bottomless cuboid; wherein,

[0055] The planar calibration plate is made of planar glass, and the planar glass has a transmissive chessboard calibration pattern.

[0056] The backlight is fixed to the back of the five planar calibration plates and is used to provide a transmitted light source for the transmissive chessboard calibration map.

[0057] In this embodiment, the camera intrinsic parameter calibration device provided by the present invention includes a backlight and five planar calibration plates, and the five planar calibration plates form a bottomless cuboid. The planar calibration plates are made of planar glass, and a transmissive chessboard calibration pattern is also provided on the planar glass. The backlight is fixed on the back of the five planar calibration plates and is used to provide a transmissive light source for the transmissive chessboard calibration pattern.

[0058] It should be noted that the length and width of the planar calibration plate can be customized according to actual needs. In practical applications, a 1m*1m calibration plate or a 1.5m*1.5m calibration plate can be used to achieve internal parameter calibration of HFOV 60°-HFOV 200° without changing the size, pattern, or placement of the calibration diagram. It should be understood that there can be one or multiple backlights. For example, five backlights can be set on the back of five planar calibration plates respectively.

[0059] For example, the camera intrinsic parameter calibration device includes a backlight and five 1m*1m planar calibration plates, which form a bottomless cube. The planar calibration plates are made of flat glass, and a transmissive checkerboard calibration pattern is also provided on the flat glass. Five backlights are respectively located on the back of the five calibration plates, providing transmissive light to the transmissive checkerboard calibration pattern. Figure 2 As shown, Figure 2 This is a schematic diagram of a planar calibration plate according to an embodiment of the camera intrinsic parameter calibration device of the present invention, wherein 1-transmissive chessboard calibration diagram, 2-planar glass, and 3-backlight. Figure 3 This is a side view of a planar calibration plate according to an embodiment of the camera intrinsic parameter calibration device of the present invention, wherein 1-transmissive chessboard calibration diagram, 2-planar glass, and 3-backlight.

[0060] Optionally, in one feasible embodiment, the transmissive chessboard calibration map includes multiple chessboard grid units;

[0061] The chessboard grid unit includes a central rectangle and four edge rectangles respectively located at the upper left, lower left, upper right, and lower right vertices of the central rectangle, and each of the four edge rectangles has one vertex that coincides with one of the four vertices of the central rectangle.

[0062] In this embodiment, the transmissive chessboard calibration diagram in the camera intrinsic parameter calibration device includes multiple chessboard grid units. Each chessboard grid unit includes a central rectangle and four edge rectangles respectively set at the upper left vertex, lower left vertex, upper right vertex, and lower right vertex of the central rectangle. That is, a chessboard grid unit includes a central rectangle and four edge rectangles, and each of the four edge rectangles has a vertex that corresponds to and coincides with the four vertices of the central rectangle.

[0063] It should be noted that, for easy differentiation after camera capture, both the central and edge rectangles can be set to black. Multiple checkerboard units can form a transmissive planar calibration plate, in which, except for the central and edge rectangles, all other positions are filled with white. It should be understood that this invention does not limit the color of the checkerboard; those skilled in the art can modify the color of the checkerboard units in the camera intrinsic parameter calibration device according to calibration needs. It should also be understood that the transmissive checkerboard calibration diagram must be printed onto a flat glass surface using high-resolution printing methods. If the printing method has low resolution, it will affect the camera's intrinsic parameter calibration results.

[0064] For example, the high-resolution transmissive checkerboard pattern printed in the camera intrinsic parameter calibration device of the present invention includes multiple checkerboard units, and each checkerboard unit includes a central rectangle and four edge rectangles respectively set at the upper left vertex, lower left vertex, upper right vertex and lower right vertex of the central rectangle. That is, a checkerboard unit includes a central rectangle and four edge rectangles, and each of the four edge rectangles has a vertex that corresponds to and coincides with the four vertices of the central rectangle. Figure 4 This is a schematic diagram of a checkerboard unit in an embodiment of the camera intrinsic parameter calibration device of the present invention, wherein 4-center rectangle, 5-upper left edge rectangle, 6-upper right edge rectangle, 7-lower right edge rectangle, 8-lower left edge rectangle, 9-corner point. Figure 4 In the chessboard grid shown, the central rectangle and edge rectangles are both set to black. The lower right vertex of the upper left edge rectangle coincides with the upper left vertex of the central rectangle, the lower left vertex of the upper right edge rectangle coincides with the upper right vertex of the central rectangle, the upper left vertex of the lower right edge rectangle coincides with the lower right vertex of the central rectangle, and the upper right vertex of the lower left edge rectangle coincides with the lower left vertex of the central rectangle. Each coinciding vertex is called a corner point. Figure 5 This is a schematic diagram of a transmissive chessboard calibration according to an embodiment of the camera intrinsic parameter calibration device of the present invention. The transmissive chessboard calibration diagram includes multiple... Figure 4 The checkerboard grid cells shown are all black in the center and edge rectangles, with the rest filled in white.

[0065] Optionally, in one feasible embodiment, the central rectangle is further provided with a QR code, which is used to store the coordinates of the four vertices of the central rectangle.

[0066] In this embodiment, the checkerboard unit includes a central rectangle and four edge rectangles. A QR code can also be set in the central rectangle, which can store the coordinates of the four vertices of the central rectangle.

[0067] It should be noted that the coordinates of the four vertices can be represented by a QR code in two ways: either the coordinates of one vertex are set, and the coordinates of the other three vertices are derived from the length and width of the central rectangle; or the coordinates of all four vertices of the central rectangle can be represented within the QR code. It's important to understand that although each chessboard square includes a central rectangle and four edge rectangles, the QR code within the central rectangle can be different. Furthermore, for ease of distinction, if the central and edge rectangles are set to black, the QR code within the central rectangle can be set to white.

[0068] For example, such as Figure 4 As shown, a checkerboard unit can be a black central rectangle and four black edge rectangles, with a white QR code storing the coordinates of the four vertices within the central rectangle. Assuming the central rectangle is a 7cm x 7cm square, and the QR code only stores the coordinates of the bottom-left vertex, then during camera intrinsic parameter calibration, the coordinates of the top-left, top-right, and bottom-right vertices of the square can be derived from the bottom-left vertex coordinates and the square's side length of 7cm. When the QR code directly stores the coordinates of the four corner points, no calculation is required.

[0069] In this embodiment, the present invention provides a three-dimensional, five-sided transmissive checkerboard-pattern camera intrinsic parameter calibration device with QR codes. This device can minimize the reprojection error across the entire field of view of the camera, reduce the manufacturing cost of the planar calibration plate for camera intrinsic parameter calibration, and ensure consistent calibration accuracy at the edges and center for both ordinary cameras and fisheye cameras. This not only improves the efficiency of camera intrinsic parameter calibration but also allows the calibration accuracy error of the camera to be controlled within 5 to 10 pixels by using corner coordinates.

[0070] Based on the structure of the camera intrinsic parameter calibration device described above, the overall concept of various embodiments of the camera intrinsic parameter calibration method of the present invention is proposed.

[0071] In this embodiment of the invention, the camera, as a device capable of recording images, plays an indispensable role in people's lives. After leaving the factory, to minimize image distortion, the camera requires both external and internal parameter calibration.

[0072] Traditional camera intrinsic parameter calibration uses a planar black and white checkerboard calibration diagram, as shown in the diagram below. Figure 6As shown, the calibration patterns are customized by each manufacturer. However, this type of calibration method is not flexible in use. For example, cameras with a small field of view require smaller calibration patterns, but they need to be placed at a greater distance; fisheye lenses have a larger field of view, typically requiring 2m*3m calibration patterns, which occupy more space and are more expensive. Figure 7 The diagram shows a traditional planar checkerboard calibration. Different field-of-view angles require different levels of precision in intrinsic parameter calibration. For example, a lens with a small field of view only needs one plane for calibration; however, fisheye lenses have significant distortion, resulting in better imaging in the central area but severe distortion at the edges, making it difficult to achieve the same calibration precision in the center and edges during the algorithm process.

[0073] Therefore, how to achieve the same calibration accuracy at the edges and center of a camera while maintaining low cost and high flexibility is a technical problem that urgently needs to be solved in this field.

[0074] To address the aforementioned problems, this invention proposes a camera intrinsic parameter calibration method based on the aforementioned camera intrinsic parameter calibration device. The camera intrinsic parameter calibration method includes: moving the camera to be calibrated to the center position of the camera intrinsic parameter calibration device using a preset sliding device; controlling the camera at the center position to capture multiple calibration images; and calibrating the camera intrinsic parameters based on the multiple calibration images.

[0075] Based on the aforementioned camera intrinsic parameter calibration device, the present invention proposes a camera intrinsic parameter calibration method comprising: firstly, moving the camera to be calibrated to the center position of the camera intrinsic parameter calibration device using a preset sliding device; then controlling the camera at the center position of the camera intrinsic parameter calibration device to capture multiple calibration images for intrinsic parameter calibration; and then calibrating the camera intrinsic parameters based on the corresponding information in the calibration images.

[0076] Compared to the traditional method of calibrating cameras using a planar checkerboard calibration map, the camera intrinsic parameter calibration method proposed in this invention, based on a camera intrinsic parameter calibration device, can complete the intrinsic parameter calibration of cameras with HFOV 60°-HFOV 200° without changing the size, pattern, or distance between the calibration map and the camera, thus improving the efficiency of camera intrinsic parameter calibration.

[0077] Based on the overall concept of the camera intrinsic parameter calibration method of the present invention, various embodiments of the camera intrinsic parameter calibration method of the present invention are proposed.

[0078] Please refer to Figure 8 , Figure 8This is a flowchart illustrating the first embodiment of the camera intrinsic parameter calibration method of the present invention. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps of the camera intrinsic parameter calibration method of the present invention can be performed in a different order.

[0079] Furthermore, in this embodiment, the execution subject of the camera intrinsic parameter calibration method of this application can be an external terminal device. For ease of explanation and reading comprehension, the following text will use the terminal device as the execution subject to describe the embodiments of the camera intrinsic parameter calibration method of this application.

[0080] In this embodiment, the camera intrinsic parameter calibration method of the present invention is applied to the above-mentioned camera intrinsic parameter calibration device. The camera intrinsic parameter calibration method of the present invention includes:

[0081] Step S10: Move the camera to be calibrated to the center position of the camera intrinsic parameter calibration device using a preset sliding device;

[0082] In this embodiment, before calibrating the intrinsic parameters of the camera to be calibrated using the camera intrinsic parameter calibration device, the camera to be calibrated is first fixed in a preset sliding device, and then the terminal device moves the camera to the center position of the camera intrinsic parameter calibration device through the sliding device.

[0083] It should be noted that the sliding device is a device that can slide horizontally and / or vertically.

[0084] Step S20: Control the camera located at the center position to capture multiple calibration images;

[0085] In this embodiment, after the terminal device moves the camera to be calibrated to the center position of the camera intrinsic parameter calibration device by sliding the device, the terminal device then controls the camera at the center position to take multiple calibration images.

[0086] Step S30: Perform intrinsic parameter calibration on the camera based on multiple calibration images.

[0087] In this embodiment, after the terminal device controls the camera located at the center of the camera intrinsic parameter calibration device to capture multiple calibration images, the terminal device then performs intrinsic parameter calibration on the camera based on the obtained multiple calibration images.

[0088] For example, the preset sliding device can be a three-axis slide table. Figure 9 The diagram shows a schematic representation of the three-axis slide used in the camera intrinsic parameter calibration method of the present invention, wherein 10 is the X-slide, 11 is the Y-slide, and 12 is the hollow rotary platform. Figure 10The diagram illustrates a fisheye lens imaging schematic of an embodiment of the camera intrinsic parameter calibration method of the present invention. When the terminal device calibrates the camera using the camera intrinsic parameter calibration device, the camera is first fixed on a three-axis slide. Then, the terminal device moves the camera to the center position of the camera intrinsic parameter calibration device using the X and Y slides of the three-axis slide. Next, the terminal device controls the camera at the center position to capture multiple calibration images, and then performs intrinsic parameter calibration on the camera based on these multiple calibration images.

[0089] In this embodiment, the present invention moves the camera to be calibrated to the center position of the camera intrinsic parameter calibration device by a three-axis slide, and then takes multiple calibration images by the camera at the center position. The camera is then calibrated based on the multiple calibration images. This method achieves consistent calibration accuracy in the middle and edges of ordinary cameras and fisheye cameras. Furthermore, by calibrating multiple types of cameras with a single camera intrinsic parameter calibration device, the production cost of the calibration device is reduced.

[0090] Furthermore, based on the first embodiment of the camera intrinsic parameter calibration method of the present invention described above, a second embodiment of the camera intrinsic parameter calibration method of the present invention is proposed.

[0091] In this embodiment, the camera intrinsic parameter calibration method further includes:

[0092] Step S40: Obtain the rotation angle of the camera during calibration;

[0093] In this embodiment, in the camera intrinsic parameter calibration method, the terminal device also needs to obtain the rotation angle of the camera during calibration.

[0094] For example, the camera intrinsic parameter calibration method further includes: the terminal device acquiring the rotation angle of the camera when it takes a picture, so as to determine the number of calibration images taken.

[0095] Step S20 above: Controlling the camera located at the center position to capture multiple calibration images, including:

[0096] Step S201: Control the camera located at the center position to take multiple calibration images according to the rotation angle.

[0097] In this embodiment, after the terminal device controls the sliding device to move the camera to the center position of the camera intrinsic parameter calibration device, the terminal device then controls the camera at the center position to take multiple calibration images according to the rotation angle.

[0098] It should be noted that the rotation angle is related to the number of calibration images captured. It should be understood that the number of calibration images is positively correlated with the computational load of the terminal. The larger the number of calibration images, the more computation the terminal needs. In practical applications, those skilled in the art can control the rotation angle of the camera based on the computational load of the terminal, and this invention does not impose any restrictions on this.

[0099] For example, after the terminal device fixes the camera on the three-axis slide and controls the three-axis slide to move the camera to the center position of the camera intrinsic parameter calibration device, assuming the rotation angle is set to 10°, the terminal device controls the camera at the center position to rotate 360° through the hollow rotation platform of the three-axis slide, and will obtain 36 calibration images; if the rotation angle is set to 1°, the terminal device controls the camera at the center position to rotate 360 ​​times through the hollow rotation platform of the three-axis slide, and will obtain 360 calibration images.

[0100] Optionally, in a feasible embodiment, step S30 above: performing intrinsic parameter calibration on the camera based on multiple calibration images, includes:

[0101] Step S301: Extract coordinate information from multiple calibration images to obtain calibration image coordinate information;

[0102] In this embodiment, after the terminal device controls the camera to rotate and capture multiple calibration images through the sliding device, the terminal device then performs coordinate information extraction processing on the multiple calibration images to obtain the calibration image coordinate information.

[0103] It should be noted that the calibration image coordinate information refers to the coordinate information of each corner point obtained through the QR code in the transmissive chessboard grid.

[0104] Step S302: Perform intrinsic parameter calibration on the camera based on the calibration image coordinate information.

[0105] In this embodiment, after the terminal device extracts coordinate information from multiple calibration images to obtain calibration image coordinate information, the terminal device then performs intrinsic parameter calibration on the camera based on the calibration image coordinate information.

[0106] For example, after the terminal device controls the camera to rotate and capture multiple calibration images through the hollow rotating platform of the three-axis slide, the terminal device then performs coordinate information extraction processing on the obtained calibration images to obtain calibration image coordinate information that represents the coordinates of each corner point in the multiple calibration images, and then performs intrinsic parameter calibration on the camera based on the image coordinate information.

[0107] Optionally, in a feasible embodiment, step S302 above: performing intrinsic parameter calibration on the camera based on the calibration image coordinate information, includes:

[0108] Step S3021: Obtain the distortion coefficient and optical center of the camera based on the calibration image coordinate information to complete the intrinsic parameter calibration of the camera.

[0109] In this embodiment, after obtaining the calibration image coordinate information, the terminal device then obtains the distortion coefficient and optical center of the camera based on the calibration image coordinate information to complete the intrinsic parameter calibration of the camera.

[0110] For example, after obtaining the coordinate information of the calibration images from multiple calibration images, the terminal device obtains the distortion coefficient and optical center of the camera based on the coordinate information of the calibration images, so as to complete the intrinsic parameter calibration of the camera.

[0111] Optionally, in a feasible embodiment, the center position includes: a bottom center position and a vertical center position. Step S10 above, which involves moving the camera to be calibrated to the center position of the camera intrinsic parameter calibration device using a preset sliding device, includes:

[0112] Step S101: Move the camera to be calibrated to the bottom center position of the camera intrinsic parameter calibration device using a preset sliding device;

[0113] In this embodiment, after the camera is fixed on the preset sliding device, the terminal device controls the sliding device to move the camera to be calibrated to the bottom center position of the camera intrinsic parameter calibration device.

[0114] Step S102: Move the camera, which is located at the bottom center position, to the vertical center position of the camera intrinsic parameter calibration device using the sliding device.

[0115] In this embodiment, the terminal device moves the camera to be calibrated to the bottom center position using a sliding device, and then moves the camera at the bottom center position to the vertical center position using the sliding device.

[0116] It should be noted that moving the camera to the center position can also be done by first moving it to the vertical center position and then moving it to the bottom center position.

[0117] For example, after fixing the camera on the three-axis slide, the terminal device controls the X slide to send the camera to the bottom center position of the stereo calibration panel, and then uses the Y slide of the three-axis slide to adjust the camera at the bottom center position to the vertical center position in the vertical direction of the stereo calibration panel.

[0118] In this embodiment, the present invention moves the camera to the center position of the camera intrinsic parameter calibration device through a sliding device, and then controls the camera at the center position to automatically rotate by a preset angle to capture multiple calibration images from different angles. Then, the camera intrinsic parameters are calibrated based on the corner coordinates represented by the QR code in the calibration images from different angles. This method allows the terminal device to locate the spatial position of each corner point and adapt to different camera resolutions and camera field of view. It can also complete the intrinsic parameter calibration of multiple cameras with one camera intrinsic parameter calibration device, saving calibration board space occupancy and reducing production costs. Furthermore, it achieves high-precision intrinsic parameter calibration of the camera's edge and center.

[0119] In addition, this invention also proposes a camera intrinsic parameter calibration system.

[0120] Please refer to Figure 11 The camera intrinsic parameter calibration system of the present invention includes:

[0121] The position moving module 10 is used to move the camera to be calibrated to the center position of the camera intrinsic parameter calibration device by means of a preset sliding device;

[0122] Image capturing module 20 is used to control the camera located at the center position to capture multiple calibration images;

[0123] The intrinsic parameter calibration module 30 is used to calibrate the intrinsic parameters of the camera based on multiple calibration images.

[0124] Optionally, the camera intrinsic parameter calibration system further includes:

[0125] The first acquisition module is used to acquire the rotation angle of the camera during calibration;

[0126] Image capturing module 20 includes:

[0127] A rotating shooting unit is used to control the camera located at the center position to capture multiple calibration images according to the rotation angle.

[0128] Optionally, the intrinsic parameter calibration module 30 includes:

[0129] A coordinate information extraction unit is used to extract coordinate information from multiple calibration images to obtain calibration image coordinate information.

[0130] The calibration unit is used to perform intrinsic parameter calibration on the camera based on the calibration image coordinate information.

[0131] Optionally, the calibration unit includes:

[0132] The calibration subunit is used to obtain the distortion coefficient and optical center of the camera based on the calibration image coordinate information, so as to complete the intrinsic parameter calibration of the camera.

[0133] Optionally, the center position includes: a bottom center position and a vertical center position; the position moving module 10 includes:

[0134] The bottom calibration unit is used to move the camera to be calibrated to the bottom center position of the camera intrinsic parameter calibration device via a preset sliding device;

[0135] A vertical correction unit is used to move the camera, which is located at the bottom center position, to the vertical center position of the camera intrinsic parameter calibration device via the sliding device.

[0136] Furthermore, the present invention also proposes a storage medium storing a camera intrinsic parameter calibration program, which, when executed, implements the steps of the camera intrinsic parameter calibration method of the present invention as described above.

[0137] The specific embodiments of the storage medium of the present invention are basically the same as the embodiments of the above-described camera intrinsic parameter calibration method, and will not be described in detail here.

[0138] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0139] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0140] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be an in-vehicle computer, smartphone, computer, or server, etc.) to execute the methods described in the various embodiments of this application.

[0141] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for calibrating intrinsic parameters of a camera, characterized in that, The camera intrinsic parameter calibration method is applied to a camera intrinsic parameter calibration device, which includes: five backlights, five planar calibration plates, and the five planar calibration plates forming a bottomless cuboid; wherein, the planar calibration plates are made of planar glass, and the planar glass has a transmissive chessboard calibration pattern, the transmissive chessboard calibration pattern including multiple chessboard grid units, each chessboard grid unit including a central rectangle and four edge rectangles respectively located at the upper left vertex, lower left vertex, upper right vertex, and lower right vertex of the central rectangle, and the four edge rectangles... Each of the edge rectangles has one vertex that coincides with one of the four vertices of the central rectangle. The central rectangle contains a QR code for storing the coordinates of one or all four vertices. After capturing multiple calibration images, the camera, positioned at the center of the camera intrinsic parameter calibration device, uses the coordinates stored in the QR code within these images to perform intrinsic parameter calibration. Five backlights are fixed to the back of the five planar calibration plates, providing a transmitted light source for the transmissive chessboard calibration diagram. The camera intrinsic parameter calibration method includes: The camera to be calibrated is moved to the bottom center position of the camera intrinsic parameter calibration device by a preset three-axis slide. The camera, located at the bottom center position, is moved to the vertical center position of the camera intrinsic parameter calibration device using the three-axis slide. Control the camera located at the center position to capture multiple calibration images; The camera's intrinsic parameters are calibrated based on multiple calibration images.

2. The camera intrinsic parameter calibration method as described in claim 1, characterized in that, The camera intrinsic parameter calibration method also includes: Obtain the rotation angle of the camera during calibration; The step of controlling the camera located at the center position to capture multiple calibration images includes: The camera, positioned at the center, is controlled to capture multiple calibration images according to the rotation angle.

3. The camera intrinsic parameter calibration method as described in claim 1, characterized in that, The step of calibrating the intrinsic parameters of the camera based on multiple calibration images includes: Coordinate information extraction processing is performed on multiple calibration images to obtain calibration image coordinate information; The camera's intrinsic parameters are calibrated based on the calibration image coordinate information.

4. The camera intrinsic parameter calibration method as described in claim 3, characterized in that, The step of calibrating the intrinsic parameters of the camera based on the calibrated image coordinate information includes: The distortion coefficient and optical center of the camera are obtained based on the calibration image coordinate information to complete the intrinsic parameter calibration of the camera.

5. A camera intrinsic parameter calibration system, characterized in that, For implementing the camera intrinsic parameter calibration method as described in any one of claims 1 to 4, the camera intrinsic parameter calibration system comprises: The position movement module is used to move the camera to be calibrated to the bottom center position of the camera intrinsic parameter calibration device via a preset three-axis slide; and to move the camera at the bottom center position to the vertical center position of the camera intrinsic parameter calibration device via the three-axis slide. An image capturing module is used to control the camera located at the center position to capture multiple calibration images; The intrinsic parameter calibration module is used to calibrate the intrinsic parameters of the camera based on multiple calibration images.

6. A storage medium, characterized in that, The storage medium stores a camera intrinsic parameter calibration program, which, when executed, implements the steps of the camera intrinsic parameter calibration method as described in any one of claims 1 to 4.

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