tailieunhanh - Báo cáo hóa học: " Research Article Pattern Projection with a Sinusoidal Phase Grating"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Pattern Projection with a Sinusoidal Phase Grating | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 351626 10 pages doi 2009 351626 Research Article Pattern Projection with a Sinusoidal Phase Grating Elena Stoykova Jana Harizanova and Ventseslav Sainov Central Laboratory of Optical Storage and Processing of Information Bulgarian Academy of Sciences P. O. Box 95 1113 Sofia Bulgaria Correspondence should be addressed to Elena Stoykova elena@ Received 1 October 2007 Accepted 21 March 2008 Recommended by John Watson The aim of this work is to study the diffractive properties of a sinusoidal phase grating for incorporation as a pattern projection element in a multisource and multicamera phase-shifting profilometric system. Two challenges should be overcome for successful operation of such a system which are connected to inherent limitations of the phase-shifting algorithm requirements for a sinusoidal fringe profile and for equal background and contrast of fringes in the recorded patterns. As a first task we analyze the frequency content of the projected fringes in the Fresnel diffraction zone for parallel and divergent light illumination at different grating parameters and wavelengths. As a second task we evaluate the systematical errors due to higher harmonics and multiwavelength illumination. Finally operation of the four-wavelength profilometric system is simulated and the error of the profilometric measurement evaluated. The results of test measurements are also presented. Copyright 2009 Elena Stoykova et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. Introduction Parallel acquisition of information as an inherent property of optical methods stimulated development of various optical techniques for noncontact measurement of surfaces of 3D objects and scenes. Among existing .