Research On Structure Light Depth Perception Method Based On Phase-Shifting

Phase shift depth perception is a structured light depth sensing method that uses phase shift coding patterns.Due to its high resolution and high precision,it is widely used in the fields of cultural relics protection,biomedical,media art,industrial manufacturing and national defense.In the phase shift depth sensing method,nonlinear error and phase unwrapping error are the key factors that limit its development.Among them,the nonlinear error refers to the error caused by the distortion of the phase shift coding pattern caused by the gamma effect of the projector,and the phase unwrapping error is an error caused by the ambient light of the depth perception scene and the surface color of the object.Based on the analysis and summary of relevant research results at home and abroad,this thesis makes a comprehensive evaluation of the existing methods,and deeply studies the phase shift depth perception algorithm.The main research contents and innovations of this thesis are shown in the following aspects:First of all,this thesis builds a phase shift depth sensing hardware system.It is used to compare the proposed algorithm with the traditional phase shift depth sensing technology.In order to meet the requirements of the depth sensing system for the position of the equipment,the system calibration was carried out according to the Zhang Zhengyou calibration method.Then,based on the nonlinear error problem in the phase-shifting depth perception method,a Binary Pattern Optimization Algorithm Based on Tabu Search(BPTS)algorithm is designed.The BPTS algorithm is based on error diffusion technology.It introduces the idea of Tabu Search algorithm to obtain high-quality binary projection patterns.Combined with the defocus projection scheme,it can perfectly avoid nonlinear errors,reduce relative phase errors,and improve the accuracy of depth perception..Finally,this thesis designs a timing phase unwrapping algorithm based on CGC coding for the error of phase unwrapping in phase-shifting depth perception method,that is,the poor performance of complex measurement environment with ambient light and object surface color interference.Compared with the traditional GCM algorithm,the CGC algorithm is superior in terms of robustness,accuracy and practicability.The experimental results show that the phase shift depth sensing method based on BPTS algorithm and CGC phase unwrapping algorithm has a great improvement in accuracy,robustness and practicability.