3D measurement system based on divergent multi-line structured light projection, its accuracy analysis

Abstract

This paper proposes an effective three-dimensional(3D) measurement system based on divergent multi-line structured light projection, and analyzes the measurement accuracy of the system. In the system, the previous methods have been improved. The accuracy of system calibration and 3D measurement can be improved effectively by changing the calibration board, changing the relative distance between the camera and the laser. Firstly, the camera calibration and the light plane calibration are realized by projecting a circular calibration board and a blank board. Secondly, the Steger centerline extraction algorithm is used to complete the extraction of the centerline of the stripe. Finally, based on the system calibration parameters and the centerline extraction results, the surface 3D measurement of the object is realized, and the camera calibration, light plane calibration and 3D measurement accuracy are analyzed. Experiments show that the calibration method proposed in this paper can obtain higher accuracy than the checkerboard calibration method, which can reduce the camera calibration error by more than 3 times and the light plane calibration error by more than 1 times. In addition, compared with the previous calibration method, the blank board avoids the influence of the calibration pattern on the light stripe. Finally, the relative error of light plane calibration is controlled within 1% by changing the relative distance between the camera and the laser.