6 results about "Checkerboard pattern" patented technology

This invention provides an underwater immersed tube positioning and monitoring method, a docking monitoring method, and related equipment. By pre-setting a black and white checkerboard pattern on the immersed tube and using an underwater robot equipped with a binocular camera to photograph and identify the checkerboard pattern, reliable calculation of the immersed tube's position and attitude can be achieved in complex underwater environments. Compared to existing assisted positioning methods using active laser targets, this invention utilizes a black and white checkerboard pattern as a passive visual marker, which has the advantages of simple structure, low manufacturing cost, convenient deployment, and no need for retrieval. It can effectively reduce the investment in underwater construction auxiliary equipment and work processes. Combined with underwater robot operations, it can also reduce the risks of manual underwater operations and improve the safety, practicality, and engineering economy of immersed tube positioning and monitoring.

This invention discloses a method and apparatus for calibrating a telecentric structured light system based on the geometric center of a checkerboard pattern. The method includes: selecting test calibration board images from a set of calibration board images; performing image edge detection and binarization based on the Sobel operator to obtain a binarized edge map; performing line detection based on the Hough transform, calculating the rotation correction angles corresponding to the vertical lines of the checkerboard pattern, and constructing a rotation matrix using the rotation correction angles; constructing a standard checkerboard pattern template based on ROI selection and edge expansion processing of the test calibration board images; performing normalization processing on each calibration board image, and then performing template matching and sub-pixel-level center localization with the standard checkerboard pattern template to finally determine the center coordinates of the checkerboard pattern in the corresponding calibration board image as feature point coordinates; and using the rotation matrix to perform attitude correction on the feature point coordinates of each calibration board image, thereby calibrating the telecentric structured light system. This invention can significantly improve calibration accuracy and stability.

This invention proposes a method for uncoupling a train using a robot, belonging to the field of train uncoupling technology. The method involves collecting the position and speed of the train carriage, and simultaneously determining whether the carriage has entered the robot's grasping window. If the carriage has not entered the window, but the robot has, the camera is activated and acquires RGB and depth images. The depth image is then registered to the color image, and the point cloud coordinates of the coupler are calculated. The robot receives the grasping path and executes the grasping action according to the order of the points forming the path. Once the carriage is uncoupled, the robot's grasping action is complete. The acquisition of RGB and depth images utilizes a perspective projection model and Zhang Zhengyou calibration method to acquire multiple sets of checkerboard patterns. This method overcomes the challenges of complex uncoupling environments, numerous obstacles, short uncoupling windows, and unfavorable lighting conditions that can lead to uncoupling failures.

This invention discloses a cabin relative pose detection system and calibration method based on non-cooperative assembly characteristics, belonging to the field of automated docking and assembly technology for large cabin sections. The method first uses a laser tracker as a spatial reference to perform nonlinear error calibration and optimal measurement position compensation on multiple displacement sensors in the measuring device. Then, by pushing a calibration plate and simultaneously acquiring images from a vision camera, a mapping relationship between image pixel size and spatial distance is established. Finally, the in-situ calibration of the measuring device is completed. This invention eliminates the need for complex camera parameter calibration using checkerboard patterns or dedicated targets. Through sensor data fusion and spatial mapping, it achieves high-precision and high-efficiency relative pose calculation of cabin non-cooperative assembly characteristics. This method is applicable to flexible assembly scenarios of multiple types and varying batches of cabin sections, effectively improving the assembly quality and consistency of aerospace products such as missiles.

The application discloses a high-robustness and high-precision camera calibration board and an angle point detection method. The method comprises the following steps: forming an expected calibration board by combining an ArUco code pattern and a black-and-white checkerboard pattern; establishing a calibration board coordinate system and setting an ArUco code pattern angle point in the calibration board coordinate; collecting a calibration board image to obtain a pixel coordinate of the ArUco code pattern angle point; using the calibration board coordinate and the pixel coordinate to solve a projection transformation matrix T from the calibration board coordinate system to a pixel coordinate system; using the projection transformation matrix T and a known model of the calibration board to calculate a pixel coordinate of a black-and-white checkerboard angle point; and using a sub-pixel algorithm to obtain an accurate pixel coordinate of the black-and-white checkerboard angle point. The application solves the problems of low accuracy of the ArUco code pattern angle point coordinate, a small number of angle points, and the black-and-white checkerboard pattern being easily affected by environmental interference, a placing posture, backlight, local shadow and the like, leading to detection failure and angle point loss.

This invention provides a method, apparatus, medium, and device for determining distortion parameters of a camera module. The method requires only capturing one image of a checkerboard pattern and performing anti-distortion processing on the corner points of the checkerboard image to reduce deviations caused by image distortion. Furthermore, through homography matrix transformation, perspective distortion caused by the shooting angle is reduced, minimizing the impact of perspective interference on distortion parameters. Then, through fine-tuning of distortion parameters, anti-distortion processing, and closed-loop processing of matrix deviation, the distortion parameters are ensured to always be optimized towards the direction of minimum deviation. The final target distortion parameters closely match the true distortion characteristics of the camera module under test, ensuring the accuracy of distortion parameter determination. The entire testing process does not require limiting the shooting environment or capturing multiple images for analysis, making the operation relatively simple and thus improving the efficiency of distortion parameter determination.