Contour Measurement Of Specular Target Based On Line Structed Light

Three-dimensional outline of the object parameters is an important parameter in surface quality inspection and surface processing. People have done a lot of research in three-dimensional contour measuring. With the rapid development of computer technology, laser technology and digital image processing technology, the optical three-dimensional contour measurement has taken a dominant role in the three-dimensional contour measurement. Different from traditional three-dimensional contour measurement techniques, optical three-dimensional contour measurement have advantages of being non-contacting and non-damaging, high-resolution, high speed of data acquisition, real-time and easy to realize, which make it to be more widely used and developed in automatic testing, quality control, reverse engineering, machine vision and other areas.However, with the appearance of a large number of components of specular surfaces, conventional optical three-dimensional measurement method is no longer applicable. The main reason for this difficulty is the diffuse light in the conventional optical measurement. Specular surface has a high reflection characteristic. Strong surrounding environment light will result that image capture device being unable to collect correct image information. How to address the impact of specular reflection to measure the three-dimensional contour of the specular object becomes a hot topic. For these special and very common specular objects, this thesis presents a method of two-camera vision based on line-structured light in measurement of specular objects, by collecting the weak diffuse optical of specular surfaces. In this thesis, a lock-in image technique and an image enhancement method of linear superposition is applied, which can eliminate background light’s interference, reduce noise in the image, keep feature information of the target and enhance image feature information.This thesis first studies the principle of line-structured light three-dimensional measurement and two-camera calibration method. Secondly, the thesis studies three-dimensional contour reconstruction algorithm and determine the use of contour stitching algorithm. Then the thesis introduces pre-image processing algorithm of band of light image, which can solve the problem of discontinuous contours and burrs. Finally, the thesis designs a specular target measuring system from hardware and software aspects. With the measuring system, a plane mirror and a highly reflective metal are measured.