Complete calibration of a structured light stripe vision sensor through a single cylindrical target

Abstract

In a complex industrial environment, it is not appropriate to use the traditional Zhang's calibration method to shoot multiple checkerboard images in different positions, and due to the contour characteristics of the cylindrical target, camera calibration and line-structured calibration can be simultaneously performed. Therefore, a complete calibration method for a line-structured light system based on a single cylindrical target is proposed. The calibration process is as follows: Placing the cylindrical target at least once and illuminate it with the light strip of the laser projector. The vision sensor captures the target image and then extracts the laser stripes and contour images of the cylindrical target. According to the contour characteristics of the cylindrical target and the definition of the collinear vector, the extracted contour image is used to solve the internal parameters of the camera. Because the line-structured light plane and cylindrical target intersection line in the axial of cylindrical is a standard circle, the equation of the light plane is established on the camera coordinate system. The effectiveness of the method is verified by simulation and physical experiments. The experimental results show that the RMS errors of the 30 distance is 0.07 mm. The proposed method does not need to rely on the constraints of multiple images and is simple to operate, meeting the requirements of industrial 3D measurement technology.