Research Of 3-D Reconstruction Methods In Reverse Engineering

3-D shape measurement and graphics model reconstruction is a branch of computer image processing and a research direction that integrates machine vision and computer image and graph processing. It has a wide and urging application in the fields of Automation Process, Machine Vision, CAD, Virtual Reality (VR), Medicine and so on. However, it is an important but difficult problem to design a technology that can be used to measure 3-D surface of an object nicely and rapidly and can recover 3-D shape by this information. This paper presents a method named Grating Projection that captures the 3-D surface profilometry of an object without any contact but high speed. It is a global measurement technology. Because of the cragginess of the 3-D surface, the distortion stripes appear when the common rectangular grating or sine grating is projected onto the object surface, which includes information about the 3-D surface profilometry. The images including distortion stripes are taken by CCD camera. The 2-D stripes information is got after processing these images according to triangular requirements. On the basis of mathematic reconstruction model and arithmetic, the 3-D surface profilometry data are gotten. Furthermore, this paper presents three phase methods' theories of grating projection and realize the phase shift measurement. The stripe images including phase information are taken when several shifting phase gratings are projected onto the object surface according to phase shift measurement requirements. After analyzing these images to get the phase about the 3-D surface profilometry, the phase-height conversion arithmetic is applied to find the 3-D surface coordination data. In the last part of this paper, it analyzes the perfect measurements needed of the two methods and points out the further research direction.