Study On Combined Vision Measurement Based On Line Structured Light

The dissertation is drawn up during the work of the project 2004BS05002 which is supported by doctoral fund of Shandong province. Line Structured-light measurement system only can measure free surfaces of the objects. To meet the demand of measuring the complex prototypes completely in reverse engineering, combining to binocular stereoscopic vision system, a multi-probe measurement system that is mainly composed of a three-dimensional movement machine, a structured-light sensor and two cameras are proposed in this dissertation.Aiming to solve some key problems such as calibration, extraction of curvilinear structures from 2D images and binocular matching approach in the vision measurement filed for both line structured-light vision and binocular stereoscopic vision, comprehensive studies on them both theoretically and practically are done.The main work in the dissertation includes the following aspects:1. Aiming at the requirements of calibration, a single-tooth target is designed to get the calibration points by adjusting the laser plane to parallel to the YZ plane of the three-dimensional movement machine. The camera and the line structured-light are calibrated by using the same group calibration points according to the radial-alignment-constraint (RAC) approach. It is guaranteed that the calibration is simple, practical and convenient for the 3D data patch assembling and data merging measurement by both the line structured-light and the binocular stereo vision.2. Based on the demand of binocular stereo vision match, the Hessian matrix method is used to extract the sub-pixel curvilinear structures from 2D images to insure the precision of the measurement system.3. Aiming at the difficulty in matching and the high wrong-match rate in binocular stereoscopic vision system, the epipolar line match method, the region match method and the characteristic match method are unified in this dissertation to get the good match result. It is guaranteed that the binocular stereo vision match is precise, efficient and practical.4. Aiming at the requirements of this combined vision measurement system, the 3D data of the complex prototypes measuring by both the line structured light and the binocular stereo vision are amalgamative to achieve the 3D reconstruction of complex prototypes and are showed in the reverse engineering software Surfacer V10.6.Experiment studies show that the combined system can meet the demand of measuring the complex prototypes completely with high accuracy, and has high practical value.