Photographic 3D Scanning System Based On Robot Vision

As industry and information technology develop rapidly,3D optical scanner play a more and more important role in all kinds of product design and testing. The hot researches in the field are to look for a more convenient 3D measurement, to make more portable metrical equipment. Although the existing laser line type 3D scanner can satisfy the requirement of accuracy of measurement, another alternative is needed because of its changeableness, giantism and immovability.With the help of the present research, this paper will discuss and research camera 3D scanner which based on the robot vision theory. This kind of 3D scanner can make use of structured light projection technology to cast grating pattern on the surface of under test object, and make control of CCD camera to take photos of distorted pattern image, take advantage of phase measuring profilometry to determine the corresponding point that under test device present in right-and-left images and match the points according to epipolar constraint. At last, combing camera params that come from the process of calibration with triangulation measurement principle to calculate apical 3D coordinate of the surface of under test object. The way of measuing surface replace the way of measuing line, what’s more the measuring equipment is composed of optical projector, a CCD camera and a tripod, which make it easy to carry, simple to use, accurate to measure.The thesis comprehensively summarizes and overviews the existing several kinds of optical 3D measurement method, and make a deep research in phase measurement method, then briefly introduces several methods to encode grating stripe. From the actual test on the method which combine Gray code with phase-shift coding, we can conclude that only testing by Gray coding stripe,the difficulty of pattern measuring will increase gradually, which will unable to identify patterns of the images, besides, Gray code make little contribution to the solution of the phase. So we need to comebine Gray code with phase-shift code. Firstly, grading with the help of Gray code in order to make a brife division of measurement area. Secondly, making detailed classification through sine phase shift coding stripe. Then, taking full use of the four step phase-shift method to carry out phase processing of sine phase shift stripe images and calculating point cloud data of under testing object after matching the adjustive phase results through 3D technology. Finally, using OpenGL to bring 3D rendering of under test object into force which make a convenient for the user to view and check the testing result.Corroesponding to the requirements of testing, on the one hand, this paper set up a hardware platform, on the other hand, it also develop software system which including the following dodules:the CCD camera calibration, the camera control, projector control, image data disposing and 3D rendering, file management. As a whole, this hardware system possess the basic functions of 3D optical measuring instrument.