Calibration method of line-structured light based on direction and length constraints

Line-structured light vision measurement technology, owing to its significant advantages, has been widely used in the field of industrial measurement. The performance of this technology in practical applications largely depends on the calibration accuracy of the light planes. With the rapid development of modern industry, the increasing precision requirements for workpiece manufacturing necessitate higher measurement accuracy, which presents new challenges for the calibration of structured light planes. Therefore, in this paper, an accurate line-structured light calibration method is proposed. It establishes direction and length constraints among the camera's optical center, target feature points, and laser control points. Based on the double constraints and the camera's internal parameters, the three-dimensional coordinates of laser control points in the camera coordinate system can be directly computed without relying on external parameters. The experimental results demonstrate that the proposed method can achieve better light plane fitting accuracy and measurement accuracy compared to traditional light plane calibration methods. Moreover, it has been effectively applied to the 3D reconstruction of cutting points along the edges of steel plates in industrial settings, demonstrating significant practical value.