Line-Scan Camera Calibration Using an Auxiliary Camera and Dynamic Scanning
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Solution Overview
Problem
Existing line-scan camera calibration methods are affected by the accuracy of calibration objects and acquisition conditions, leading to difficulties in achieving high-precision calibration results.
Innovation Solution
A line-scan camera calibration method based on an auxiliary camera, which involves calibrating the auxiliary camera, rigidly combining it with the line-scan camera, and using a motion platform to capture images of a checkerboard calibration board and dynamic scanning images. The method calculates motion vectors, registration points, and internal parameters of the line-scan camera, as well as a rigid transformation matrix, to improve calibration accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing calibration methods based on one-dimensional calibration objects are used, then the calibration process is simple, but the calibration accuracy is low due to manufacturing accuracy limitations and acquisition condition sensitivity
Solution Approach 1:
The patent introduces a motion platform as an intermediary component to achieve precise calibration. The motion platform enables controlled movement of the line-scan camera along a straight line, allowing acquisition of multiple images at different positions. This intermediary device provides precise motion control that compensates for the limitations of simple one-dimensional calibration objects, thereby improving calibration accuracy without requiring complex calibration targets.
Solution Approach 2:
The patent transforms the calibration process from a static approach to a dynamic one. Instead of using a complex static calibration object, the system uses a simple calibration object (such as a plane mirror or flat board) and achieves high-precision calibration through dynamic movement of the camera along a straight line. The motion platform enables the system to capture images at multiple predetermined positions, and through dynamic scanning, the line-scan camera acquires images at multiple rows, converting spatial movement into calibration information.
2Measurement precision
If multiple images at different positions are captured to improve calibration accuracy, then the precision increases, but the number of images and calibration time increase
Solution Approach 1:
The patent uses dynamic scanning where the line-scan camera moves along a straight line and captures images at multiple rows during motion. This dynamic approach allows the system to efficiently acquire calibration data from multiple positions without requiring separate static captures for each position. The motion platform enables continuous movement while the camera captures images at predetermined positions and multiple rows, reducing total calibration time while maintaining high precision through the use of motion vectors for coordinate transformation.
Solution Approach 2:
The patent uses a plane mirror or flat board as a calibration object that creates virtual images of the motion platform's movement. By capturing images of this simple calibration object at multiple positions and using image processing to extract feature points, the system can derive calibration information without requiring complex calibration targets. The calibration object acts as a reference that copies the motion information, enabling accurate calibration through relatively simple image capture and processing.
Data Source
AI summary
A line-scan camera calibration method based on an auxiliary camera, including: calibrating the auxiliary camera, rigidly combining the auxiliary camera with a line-scan camera and installing the combined camera onto a motion platform, and placing a checkerboard calibration board within an imaging area of the combined camera; driving a motion platform to capture images and dynamic scanning images of the checkerboard calibration board, calculating a motion vector of the combined camera; calculating coordinates of registration points; fitting an equation of an imaging plane using coordinates of multiple registration points in the auxiliary camera coordinate system; calculating internal parameters of the line-scan camera and a rigid transformation matrix between the auxiliary camera and the line-scan camera based on properties of a rotation matrix and the line-scan camera imaging model. This application improves the calibration accuracy of the line-scan camera.