Line laser automatic calibration system

Abstract

This invention relates to the field of production testing equipment technology and discloses a linear laser automatic calibration system, including a base. A fixed frame, a first support frame, and a linear guide rail are fixedly mounted on the upper surface of the base. An external parameter calibration plate is disposed at the top inside the fixed frame. An internal parameter calibration plate is fixedly mounted on the side of the first support frame. A movable sub-base is movably connected to the side of the linear guide rail. A second support frame is fixedly mounted on the top of the movable sub-base. A mounting frame is fixedly mounted on the top of the second support frame. A placement seat is rotatably mounted on the inner side of the mounting frame. A camera module is disposed inside the placement seat. This invention integrates four independent checkerboard-shaped internal parameter calibration plates, allowing the camera to acquire multiple sets of data required for internal parameter calculation in a single shot, eliminating the cumbersome process of repeatedly moving the camera or calibration plate and taking 10-20 images required in traditional internal parameter calibration. Simultaneously, the linkage between the linear guide rail and the angle adjustment component allows for rapid switching of the camera orientation, achieving seamless integration of internal and external parameter calibration.

Description

Technical Field

[0001] This invention relates to the field of production testing equipment technology, specifically to a line laser automatic calibration system. Background Technology

[0002] Line laser 3D sensors are increasingly used in numerous fields such as industrial inspection and robot obstacle avoidance, especially in consumer electronics products like robotic vacuum cleaners, where market demand continues to grow and cost control requirements are becoming increasingly stringent. The accuracy of the sensor is closely related to the parameter calibration of the camera system, with the calibration of intrinsic and extrinsic parameters being a crucial factor in determining sensor performance.

[0003] Currently, traditional calibration systems use separate calibration methods for intrinsic and extrinsic parameters, which has many limitations. Intrinsic parameter calibration requires moving the camera or checkerboard to take 10-20 checkerboard images from different angles and positions, followed by complex steps such as corner detection, parameter solving, and optimization. Extrinsic parameter calibration, on the other hand, requires using a checkerboard or dot calibration board, taking at least 4 images under specific lighting conditions with the laser on and off, and solving for the extrinsic parameters by extracting the center line of the laser-illuminated area.

[0004] These traditional methods are not only cumbersome and time-consuming, increasing product manufacturing costs and production delivery cycles, but also have obvious drawbacks: when the camera angle reaches a large angle of over 100°, it is difficult to ensure that the area illuminated by the laser is on the calibration board; the shooting process requires frequent switching of lighting and laser status, which further increases the complexity and time of operation, and seriously restricts the calibration efficiency and scope of application.

[0005] To address the aforementioned issues, this invention proposes a line laser automatic calibration system that enables efficient and accurate integrated calibration of internal and external parameters. Summary of the Invention

[0006] The purpose of this invention is to provide an automatic line laser calibration system to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A linear laser automatic calibration system includes a base. A mounting frame, a first support frame, and a linear guide rail are fixedly mounted on the upper surface of the base. An external parameter calibration plate with diffuse reflection characteristics is disposed at the top interior of the mounting frame. A rotating assembly is fixedly mounted inside the mounting frame, connected to the external parameter calibration plate, and drives the external parameter calibration plate to rotate to adjust its relative position and pose with a camera module. An internal parameter calibration plate integrating four independent checkerboard patterns is fixedly mounted on the side of the first support frame. The internal parameter calibration plate is located directly above the linear guide rail. A movable base is connected to the side, and a second support frame is fixedly installed on the top of the movable base. A mounting frame is fixedly installed on the top of the second support frame. A placement seat is rotatably installed on the inner side of the mounting frame. An angle adjustment component is provided on the side of the placement seat. The angle adjustment component is connected to the placement seat and drives the placement seat to rotate to switch the camera module's orientation towards the internal parameter calibration plate or the external parameter calibration plate. The camera module is disposed inside the placement seat, and a clamping component is provided on the side of the placement seat. The camera module is fixedly installed inside the placement seat through the clamping component.

[0008] Furthermore, the rotating assembly includes a rotating rod rotatably mounted inside a fixed frame. A worm gear is fixedly mounted on the outer side of the rotating rod, and a worm meshes with the outer side of the worm gear. A first motor is fixedly mounted on the outer side of the fixed frame and is fixedly connected to the worm. A rotating plate is fixedly mounted on the top of the rotating rod and is fixedly connected to the external parameter calibration plate.

[0009] Furthermore, a groove is provided on the top of the fixed frame, and a sliding plate is welded to the bottom of the rotating plate, with the sliding plate slidably connected to the groove.

[0010] Furthermore, the angle adjustment assembly includes a second motor, which is fixedly mounted on the outside of the mounting bracket, and the output shaft of the second motor is fixedly connected to the placement seat.

[0011] Furthermore, both the first motor and the second motor are servo motors with an angle control accuracy of ≤ ±0.01°.

[0012] Furthermore, the clamping assembly includes a threaded hole, which is opened on the side of the placement seat. A threaded rod is threadedly connected inside the threaded hole, and a clamping plate is fixedly connected to the side of the threaded rod through a bearing seat. The clamping plate abuts against the camera module, and the clamping force of the clamping plate on the camera module is in the range of 5-10N.

[0013] Furthermore, a rubber pad is adhered to the side of the clamp near the camera module, and the rubber pad is made of methyl vinyl silicone rubber material.

[0014] Furthermore, four sets of supplementary lights are fixedly installed on the top of the placement base. The four sets of supplementary lights are respectively arranged around the four edges of the placement base, and the supplementary lights are narrow-band LED lights.

[0015] Furthermore, the surface of the external parameter calibration plate is covered with a high-flatness ceramic diffuse reflection layer, the flatness of the ceramic diffuse reflection layer is ≤0.005mm, and the diffuse reflectance is ≥85%.

[0016] Furthermore, the linear guide rail is equipped with a grating ruler inside, and the positioning accuracy of the grating ruler is ≤ ±0.001mm. The moving base cooperates with the linear guide rail to drive the camera module to move along a straight line, and the moving distance can be adjusted within the range of 15-50cm.

[0017] The beneficial effects of this invention are as follows: 1. This invention integrates four independent checkerboard-shaped intrinsic parameter calibration plates, allowing the camera to acquire multiple sets of data required for intrinsic parameter calculation in a single shot. This eliminates the cumbersome process of repeatedly moving the camera or calibration plate and taking 10-20 images, as required in traditional intrinsic parameter calibration. Simultaneously, the linkage between the linear guide rail and the angle adjustment component enables rapid switching of the camera orientation, achieving seamless integration between intrinsic and extrinsic parameter calibration. This eliminates the need to split the calibration process or replace equipment, significantly shortening calibration operation time and effectively reducing product manufacturing costs and production delivery cycles.

[0018] 2. The extrinsic calibration plate of this invention has diffuse reflection characteristics and its relative pose to the camera module can be flexibly adjusted by rotating components. Combined with the camera module's angle adjustment function, even in large-angle scenes where the camera angle exceeds 100° or even reaches 150°, it can ensure that the laser line is stably imaged on the ceramic diffuse reflection layer of the extrinsic calibration plate. This fundamentally solves the pain point of "the laser-illuminated area deviates from the calibration plate at large angles" in traditional calibration methods and expands the applicability of the system.

[0019] 3. Both the first and second motors of this invention are servo motors with an angle control accuracy of ≤±0.01°. The linear guide rail has a built-in grating ruler, and the positioning accuracy can reach ±0.001mm, ensuring the accuracy and repeatability of the camera position, orientation, and external parameter calibration plate pose adjustment. The high-flatness ceramic diffuse reflection layer (flatness ≤0.005mm, diffuse reflectivity ≥85%) on the surface of the external parameter calibration plate can clearly present laser line imaging, providing a stable foundation for laser line feature extraction. Combined with the precise clamping force of 5-10N of the clamping components, it avoids camera slippage or damage due to pressure, further ensuring the accuracy of the internal and external parameter calibration results and meeting the stringent requirements for sensor accuracy in industrial inspection, robot perception, and other scenarios.

[0020] 4. This invention achieves semi-automation of the calibration process through the coordinated design of mechanical structure and electronic control components, eliminating the need for frequent manual switching of lighting conditions and adjustment of equipment position, thus simplifying the operation complexity. The clamping component is equipped with rubber pads made of methyl vinyl silicone rubber, which can protect the camera module shell from scratches and adapt to camera modules of different sizes. With the adjustable movement distance of linear guide rail within the range of 15-50cm, it is compatible with various models of line laser camera modules, including consumer-grade and industrial-grade models, improving the system's versatility and market applicability.

[0021] 5. The four sets of narrow-band LED supplementary lights on the top of the mounting base of this invention can specifically improve the contrast between the laser line and the background during the external parameter calibration stage, ensuring clear laser line imaging even in strong light interference or dim environments in the workshop; the ceramic diffuse reflection layer of the external parameter calibration plate, the environmental resistance of the rubber pad, and the stability of the high-precision mechanical structure enable the system to adapt to conventional industrial environments and some complex working conditions, possessing strong environmental anti-interference capabilities and ensuring the stable conduct of calibration work. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 The explosion of the fixing frame, rotating assembly and external parameter calibration plate of the present invention Figure 1 ; Figure 3 The explosion of the fixing frame, rotating assembly and external parameter calibration plate of the present invention Figure 2 ; Figure 4 This is a schematic diagram of the second support frame structure of the linear guide rail of the present invention; Figure 5 This is an exploded view of the mounting base and camera module of the present invention; Figure 6 This is a schematic diagram of the planar structure of the linear guide rail, the second support frame, and the mounting frame of the present invention; Figure 7 This is the present invention. Figure 5 Enlarged view of point A in the middle.

[0023] Reference numerals: 1. Base; 2. Fixing frame; 3. Rotating assembly; 301. Rotating rod; 302. Worm gear; 303. Worm; 304. First motor; 305. Rotating plate; 306. Slide groove; 307. Sliding plate; 4. External parameter calibration plate; 5. First support frame; 6. Internal parameter calibration plate; 7. Linear guide rail; 8. Moving part seat; 9. Second support frame; 10. Mounting frame; 11. Placement seat; 12. Angle adjustment assembly; 1201. Second motor; 13. Camera module; 14. Clamping assembly; 1401. Threaded hole; 1402. Threaded rod; 1403. Clamping plate; 1404. Rubber pad; 15. Fill light. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the above description of the present invention, it should be noted that the terms "one side," "the other side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "identical" do not imply that components must be absolutely identical; minor differences are permissible. The term "perpendicular" simply means that the positional relationship between components is more perpendicular than "parallel," not that the structure must be perfectly perpendicular; a slight tilt is acceptable.

[0029] Figures 1-7 This is the preferred embodiment of the present invention, which is described below in conjunction with... Figures 1-7 The present invention will be further described below.

[0030] A linear laser automatic calibration system includes a base 1. A mounting bracket 2, a first support bracket 5, and a linear guide rail 7 are fixedly mounted on the upper surface of the base 1. An external parameter calibration plate 4 with diffuse reflection characteristics is disposed at the top of the interior of the mounting bracket 2. A rotating assembly 3 is fixedly mounted inside the mounting bracket 2, connected to the external parameter calibration plate 4, and drives the external parameter calibration plate 4 to rotate to adjust its relative position and orientation with the camera module 13. An internal parameter calibration plate 6 integrating four independent checkerboard grids is fixedly mounted on the side of the first support bracket 5. The internal parameter calibration plate 6 is located directly above the linear guide rail 7. A movable sub-base 8 is movably connected to the side of the linear guide rail 7. A second support bracket 9 is fixedly mounted on the top of the movable sub-base 8, and a mounting bracket is fixedly mounted on the top of the second support bracket 9. 10. A mounting base 11 is rotatably mounted on the inner side of the mounting bracket 10. An angle adjustment component 12 is provided on the side of the mounting base 11. The angle adjustment component 12 is connected to the mounting base 11 and drives the mounting base 11 to rotate to switch the orientation of the camera module 13 toward the internal parameter calibration plate 6 or the external parameter calibration plate 4. The camera module 13 is installed inside the mounting base 11. A clamping component 14 is provided on the side of the mounting base 11. The camera module 13 is fixedly installed inside the mounting base 11 through the clamping component 14. Specifically, through the linkage between the linear guide rail 7 and the angle adjustment component 12, the camera orientation can be quickly switched, realizing a seamless connection between internal parameter calibration and external parameter calibration. There is no need to disassemble the calibration process or replace the equipment, which greatly shortens the calibration operation time.

[0031] The rotating assembly 3 includes a rotating rod 301, which is rotatably mounted inside the fixed frame 2. A worm gear 302 is fixedly mounted on the outer side of the rotating rod 301, and a worm 303 meshes with the outer side of the worm gear 302. A first motor 304 is fixedly mounted on the outer side of the fixed frame 2 and is fixedly connected to the worm 303. A rotating plate 305 is fixedly mounted on the top of the rotating rod 301 and is fixedly connected to the external parameter calibration plate 4. Specifically, the rotating assembly 3 uses a worm gear 302 and worm 303 transmission combined with the first motor 304 drive, which has both high precision and strong stability. The meshing structure of the worm gear 302 and worm 303 can achieve precise angle adjustment and reliable self-locking, preventing accidental displacement of the external parameter calibration plate 4. At the same time, through the rigid connection between the rotating rod 301 and the rotating plate 305, the motor power can be smoothly transmitted to the external parameter calibration plate 4, ensuring that its rotation process is smooth and providing accurate support for external parameter calibration under different relative postures.

[0032] The top of the fixed frame 2 is provided with a sliding groove 306, and the bottom of the rotating plate 305 is welded with a sliding plate 307. The sliding plate 307 is slidably connected to the sliding groove 306. Specifically, this design provides stable support and guidance for the rotating plate 305 through the sliding cooperation between the sliding groove 306 and the sliding plate 307, effectively distributing the weight of the rotating plate 305 and the external parameter calibration plate 4, and avoiding tilting or shaking during rotation. At the same time, the sliding connection structure can reduce rotational resistance, ensure smooth rotation of the external parameter calibration plate 4, further improve the accuracy of relative posture adjustment, and ensure calibration stability.

[0033] The angle adjustment component 12 includes a second motor 1201, which is fixedly mounted on the outside of the mounting bracket 10. The output shaft of the second motor 1201 is fixedly connected to the placement seat 11. Specifically, the angle adjustment component 12 adopts a design in which the second motor 1201 is directly and rigidly connected to the placement seat 11. This design results in a short transmission path, rapid response, and quick and accurate switching of the camera module 13 orientation, efficiently adapting to the scene switching requirements of internal and external parameter calibration. At the same time, the structure is simple and compact, reducing the error and wear of intermediate transmission components. Combined with the high-precision control of the servo motor, this further ensures the accuracy and repeatability of camera angle adjustment, improving calibration efficiency and accuracy.

[0034] Both the first motor 304 and the second motor 1201 are servo motors with an angle control accuracy of ≤ ±0.01°. Specifically, the selection of servo motors with an angle control accuracy of ≤ ±0.01° as the first motor 304 and the second motor 1201 can provide ultra-high precision drive for the pose adjustment of the external parameter calibration board 4 and the orientation switching of the camera module 13, ensuring that the angle control of key components is accurate and controllable during the calibration process. At the same time, the high precision characteristics of the servo motor can ensure the repeatability of multiple adjustment actions, reduce the impact of mechanical errors on the calibration results, and lay the core power foundation for the high accuracy of internal and external parameter calibration.

[0035] The clamping assembly 14 includes a threaded hole 1401, which is located on the side of the placement base 11. A threaded rod 1402 is threadedly connected inside the threaded hole 1401. A clamping plate 1403 is fixedly connected to the side of the threaded rod 1402 via a bearing seat. The clamping plate 1403 abuts against the camera module 13, and the clamping force of the clamping plate 1403 on the camera module 13 is within the range of 5-10N. Specifically, the clamping assembly 14 adopts a threaded transmission structure, and the spacing of the clamping plate 1403 can be precisely adjusted by rotating the threaded rod 1402, adapting to camera modules 13 of different sizes. The operation is convenient and the adjustment range is flexible. The precise clamping force design of 5-10N ensures that the camera module 13 is stable and does not slip during calibration, while avoiding damage to the equipment due to excessive clamping force. Combined with the bearing seat connection method, the clamping plate 1403 is subjected to uniform force, further ensuring the stability and safety of camera installation.

[0036] A rubber pad 1404 is attached to the side of the clamping plate 1403 near the camera module 13. The rubber pad 1404 is made of methyl vinyl silicone rubber. Specifically, the rubber pad 1404 made of methyl vinyl silicone rubber is soft and has a moderate coefficient of friction. It can increase the friction with the camera module 13 during clamping, improve the fixation stability, and prevent the clamping plate 1403 from directly contacting the device shell and causing scratches or indentations. At the same time, the material has excellent elastic recovery and aging resistance. It is not easy to deform or crack after long-term use. It can adapt to the high frequency of camera loading and unloading and clamping needs, and ensure the durability of the device protection effect.

[0037] Four sets of supplementary lights 15 are fixedly installed on the top of the mounting base 11. The four sets of supplementary lights 15 are respectively set around the four edges of the mounting base 11. The supplementary lights 15 are narrow-band LED lights. Specifically, the four sets of narrow-band LED supplementary lights 15 are distributed around the four edges of the mounting base 11, which can achieve uniform supplementary lighting to the shooting area, accurately improve the contrast between the laser line and the background, and avoid the blurring of the laser line image caused by ambient light interference. The narrow-band characteristic can reduce wavelength crosstalk with the laser line, ensure the accuracy of laser line feature extraction, and the supplementary lighting range is adapted to the camera shooting field of view, without affecting the core calibration process, effectively improving the calibration reliability in complex lighting environments.

[0038] The surface of the extrinsic calibration plate 4 is covered with a high-flatness ceramic diffuse reflection layer. The flatness of the ceramic diffuse reflection layer is ≤0.005mm, and the diffuse reflectivity is ≥85%. Specifically, the high-flatness ceramic diffuse reflection layer (flatness ≤0.005mm) provides a stable reference surface for laser line imaging, avoiding laser line distortion caused by unevenness and ensuring the accuracy of extrinsic parameter calculation. The high diffuse reflectivity of ≥85% can efficiently reflect the laser line, making the laser line image clear and bright. When used with the supplementary light 15, it can further improve the distinction between the laser line and the background, adapting to the calibration needs under different lighting and angle scenarios.

[0039] The linear guide 7 is equipped with a grating ruler with a positioning accuracy of ≤±0.001mm. The moving base 8 works in conjunction with the linear guide 7 to drive the camera module 13 to move in a straight line, and the movement distance can be adjusted within the range of 15-50cm. Specifically, the linear guide 7 with a built-in grating ruler with a positioning accuracy of ≤±0.001mm provides ultra-high precision positioning for the linear movement of the camera module 13, ensuring the consistency of the position reference under different calibration distances, and laying a solid foundation for the accuracy of internal and external parameter calibration. The adjustable movement distance range of 15-50cm flexibly adapts to the calibration requirements of different relative poses. With the smooth transmission of the moving base 8, it can quickly switch calibration scenes and ensure the stability of the movement process, improving calibration efficiency and adaptability.

[0040] Working principle and usage process of this invention: I. Working Principle This laser automatic calibration system is based on "precise linkage of mechanical structure + functional synergy of core components," achieving integrated calibration of intrinsic and extrinsic parameters through modular design. Its core logic is as follows: First, the camera module 13 is fixed to a dedicated fixture, ensuring the fixture and the reference plane (extrinsic parameter calibration plate 4) are in a fixed relative position, providing a stable benchmark for calibration. Then, with the linkage of the linear guide rail 7 and the angle adjustment component 12, the camera's position and orientation are quickly switched, aligning it with the intrinsic parameter calibration plate 6 and the extrinsic parameter calibration plate 4 respectively. High-precision drive components (servo motors, grating rulers) ensure the positioning accuracy of key actions, while a high-flatness ceramic diffuse reflection layer extrinsic parameter calibration plate and a narrow-band supplementary light 15 optimize the laser line imaging quality. Combined with the integrated multi-chessboard intrinsic parameter calibration plate 6, efficient data acquisition is achieved. Finally, by segmenting the intrinsic parameter image to extract features, acquiring multiple sets of laser line images under different poses, and calculating parameters, precise calibration of the camera's intrinsic and laser-camera extrinsic parameters is completed, without the need to disassemble the calibration process or replace equipment.

[0041] Specifically: Intrinsic parameter calibration relies on an intrinsic parameter calibration plate 6 integrating four independent checkerboard grids. Multiple sets of feature data can be acquired in a single camera shot. After image segmentation, the intrinsic parameter matrix is ​​calculated using an intrinsic parameter calibration algorithm. Extrinsic parameter calibration adjusts the relative pose of the extrinsic parameter calibration plate 4 and the camera through a rotating component 3. Combined with a narrowband fill light 15, the contrast between the laser line and the background is enhanced. The camera acquires laser line imaging images under different poses, extracts the center point of the laser line, and calculates its spatial coordinates through back projection. Based on multiple sets of coordinate data, the extrinsic parameter relationship between the laser plane and the camera plane is calculated. The clamping component 14, through precise clamping force and the cooperation of the flexible rubber pad 1404, ensures the stable fixation of the camera module 13 without damage. Throughout the process, all components work together to achieve efficient and accurate calibration.

[0042] II. Usage Procedure Step 1. Fix the camera to the device: Place the camera module 13 to be calibrated into the placement seat 11, rotate the threaded rod 1402 to drive the clamping plate 1403 to move, and fix the camera module 13 with a precise clamping force of 5-10N. The methyl vinyl silicone rubber pad 1404 on the clamping plate 1403 fits against the camera shell to avoid scratches. At this time, the relative position of the clamping assembly 14 that fixes the camera and the external parameter calibration plate 4 (reference plane) remains fixed, establishing a stable reference for subsequent calibration.

[0043] Step 2. Camera facing upwards to capture the internal parameter calibration image: Activate the angle adjustment component 12, and the second motor 1201 directly drives the placement seat 11 to rotate, switching the orientation of the camera module 13 to face the internal parameter calibration plate 6 directly above; through the cooperation of the linear guide rail 7 and the moving seat 8, drive the camera module 13 to move along a straight line to the optimal shooting position for internal parameter calibration (the positioning accuracy is guaranteed to be ≤±0.001mm by the grating ruler), and the camera starts shooting and acquiring an internal parameter calibration image containing 4 independent checkerboard grids.

[0044] Step 3. Segmenting Images and Calculating Camera Intrinsic Parameters: The system segments the acquired single intrinsic parameter calibration image into four independent single chessboard images. Then, the intrinsic parameter calibration algorithm is used to extract the corner features of the chessboard and calculate the camera intrinsic parameter matrix, thus completing the intrinsic parameter calibration.

[0045] Step 4. Move the camera position so that the camera faces forward towards the external parameter calibration plate 4: After the internal parameter calibration is completed, the moving sub-base 8 is moved by the linear guide rail 7 to adjust the linear position of the camera module 13; at the same time, the angle adjustment component 12 is activated to switch the orientation of the camera module 13 from facing upward to facing forward, so that it faces the external parameter calibration plate 4 in the fixed frame 2, and the calibration scene switch is completed.

[0046] Step 5. Image capture: Turn on the line laser module and the four sets of narrow-band fill lights 15 on the top of the mounting base 11. The fill lights 15 provide uniform illumination to enhance the contrast between the laser line and the background. The camera starts capturing images to ensure that the laser light image is clearly presented in the captured image.

[0047] Step 6. Change the relative pose of the reference plane and the camera: Start the first motor 304, which drives the rotating rod 301, rotating plate 305 and external parameter calibration plate 4 to rotate synchronously through the worm gear 302 and worm 303. Combined with the sliding cooperation of the slide groove 306 and the sliding plate 307, the attitude of the external parameter calibration plate 4 (reference plane) is smoothly adjusted, thereby changing the relative pose of the reference plane and the camera. Alternatively, the position of the camera module 13 can be finely adjusted through the linear guide rail 7 to further optimize the relative pose relationship.

[0048] Step 7. Image capture: Repeat step 5, and the camera will again capture an image containing the laser line image in the current relative pose. If it is necessary to improve the accuracy of the extrinsic parameter calibration, steps 6 and 5 can be repeated to capture more sets of laser line images in different relative poses. The system extracts the center point of the laser line based on multiple sets of image data and back-projects to calculate the spatial coordinates. Finally, the extrinsic parameter matrix of the laser plane and the camera plane is calculated to complete the extrinsic parameter calibration.

[0049] Step 8. Calibration Completion and Equipment Reset: After all internal and external parameters are calibrated, the system automatically saves the calibration parameters; turn off the line laser module and the fill light 15, loosen the clamping plate 1403 of the clamping assembly 14, and take out the camera module 13; the linear guide rail 7, the rotating assembly 3, and the angle adjustment assembly 12 are all reset to their initial positions, waiting for the next calibration operation.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A line laser automatic calibration system, comprising a base (1), characterized in that: The upper surface of the base (1) is fixedly mounted with a fixing frame (2), a first support frame (5), and a linear guide rail (7). The top of the interior of the fixing frame (2) is provided with an external parameter calibration plate (4) having diffuse reflection characteristics. The interior of the fixing frame (2) is fixedly mounted with a rotating component (3). The rotating component (3) is connected to the external parameter calibration plate (4) and drives the external parameter calibration plate (4) to rotate to adjust its relative pose with the camera module (13). An internal parameter calibration plate (6) integrating 4 independent checkerboard grids is fixedly mounted on the side of the first support frame (5). The internal parameter calibration plate (6) is located directly above the linear guide rail (7). The side of the linear guide rail (7) is movably connected with a moving sub-base (8). A second support frame (9) is fixedly installed on the top of the second support frame (9), and a mounting frame (10) is fixedly installed on the top of the second support frame (9). A placement seat (11) is rotatably installed on the inner side of the mounting frame (10). An angle adjustment component (12) is provided on the side of the placement seat (11). The angle adjustment component (12) is connected to the placement seat (11) and drives the placement seat (11) to rotate to switch the camera module (13) to face the internal parameter calibration plate (6) or the external parameter calibration plate (4). The camera module (13) is provided inside the placement seat (11). A clamping component (14) is provided on the side of the placement seat (11). The camera module (13) is fixedly installed inside the placement seat (11) through the clamping component (14).

2. The automatic line laser calibration system according to claim 1, characterized in that: The rotating assembly (3) includes a rotating rod (301), which is rotatably mounted inside the fixed frame (2). A worm gear (302) is fixedly mounted on the outer side of the rotating rod (301), and a worm (303) meshes with the outer side of the worm gear (302). A first motor (304) is fixedly mounted on the outer side of the fixed frame (2), and the first motor (304) is fixedly connected to the worm (303). A rotating plate (305) is fixedly mounted on the top of the rotating rod (301), and the rotating plate (305) is fixedly connected to the external parameter calibration plate (4).

3. The automatic line laser calibration system according to claim 2, characterized in that: The top of the fixed frame (2) is provided with a sliding groove (306), and the bottom of the rotating plate (305) is welded with a sliding plate (307), and the sliding plate (307) is slidably connected to the sliding groove (306).

4. The automatic line laser calibration system according to claim 2, characterized in that: The angle adjustment assembly (12) includes a second motor (1201), which is fixedly installed on the outside of the mounting bracket (10), and the output shaft of the second motor (1201) is fixedly connected to the placement seat (11).

5. The automatic line laser calibration system according to claim 4, characterized in that: Both the first motor (304) and the second motor (1201) are servo motors with an angle control accuracy of ≤ ±0.01°.

6. The automatic line laser calibration system according to claim 1, characterized in that: The clamping assembly (14) includes a threaded hole (1401) which is opened on the side of the placement seat (11). The threaded hole (1401) is internally threaded with a threaded rod (1402). The side of the threaded rod (1402) is fixedly connected to a clamping plate (1403) through a bearing seat. The clamping plate (1403) abuts against the camera module (13), and the clamping force of the clamping plate (1403) on the camera module (13) is in the range of 5-10N.

7. The automatic line laser calibration system according to claim 6, characterized in that: A rubber pad (1404) is bonded to the side of the clamp (1403) near the camera module (13), and the rubber pad (1404) is made of methyl vinyl silicone rubber material.

8. The automatic line laser calibration system according to claim 1, characterized in that: Four sets of supplementary lights (15) are fixedly installed on the top of the placement base (11). The four sets of supplementary lights (15) are respectively arranged around the four edges of the placement base (11). The supplementary lights (15) are narrow-band LED lights.

9. The automatic line laser calibration system according to claim 1, characterized in that: The surface of the external parameter calibration plate (4) is covered with a high-flatness ceramic diffuse reflection layer, the flatness of the ceramic diffuse reflection layer is ≤0.005mm, and the diffuse reflectance is ≥85%.

10. The automatic line laser calibration system according to claim 1, characterized in that: The linear guide (7) is equipped with a grating ruler inside. The positioning accuracy of the grating ruler is ≤ ±0.001mm. The moving base (8) cooperates with the linear guide (7) to drive the camera module (13) to move along a straight line, and the moving distance can be adjusted within the range of 15-50cm.

Images