Key Technology Research, Binocular Vision System

Stereo vision is an important branch of computer vision. It plays as an important role in reverse engineering, rapid prototyping and industrial inspection, etc. It is good for realizing non-contact measuring and 3D modeling. Binocular stereovision system, which simulates the eyes of human, is the most widely used method to implement measuring technology based on vision, which provides a rapid, wide-range, maneuverable measurement method comparing to the traditional coordinate measuring machine (CMM).In order to obtain 3D data of the project rapidly, a simple, flexible and applicable binocular stereovision system was set up. Key technologies of camera calibration, feature extracting and stereo matching were also studied deeply.A hardware platform of binocular stero measuring system with simple structure was built with low cost, which consists of CCD cameras, lens, a frame grabber card, a computer and a tripod. Besides the hardware configuration, the software framework of the measuring system was also built.Camera calibration techniques were studied systematically in the thesis. Non-linear model of camera is used with all kinds of non-linear distortion factors, theoretically based on perspective projection method, in which distortion coefficient is solved by least square method. Then,a imaging model with distortion is built. Its projection matrix is sloved through perspective projection and optimized according minimization error of projection. Extrinsic and intrinsic parameters are factorized from projection matrix. In this method, two cameras are calibrated once.A method for the acquisition 3D data was implemented by distributing reference points over the projectsto be digitized and utilizing the thchniques of feature extracting, epipolae rectification, feature matching and using calibrated parameters.A binocular stereovision was built based on the hardware platform, software framework, cameras calibration and reference points'reconstruction, by which an object is measued to examine the system.