Research On Calibration Method Of 3D System With Surface Structure Light Measurement

With the rapid development of advanced manufacturing technologies and artificial intelligence technologies in the era of information technology,the acquisition and application of three-dimensional data has received more and more attention.Using three-dimensional data to achieve face recognition,cultural relics identification,product appearance and apparel design,VR(virtual reality technology)and smart manufacturing and defect detection are changing the way people live and produce.They are becoming new research hotspots.As one of the main methods for acquiring three-dimensional data,surface-structured light 3D measurement system has the advantages of non-contact,high-precision,and high-speed.Calibration is the key link influencing the measurement accuracy.This paper mainly focuses on the 3D structure of impact surface light.The Camera and system calibration method for measuring accuracy is studied.The main research contents of this paper are as follows:1.Research on camera calibration method in surface structured light three-dimensional measurement system;The basic principle of camera calibration in surface structured light three-dimensional measurement system is analyzed in detail,the sources of errors affecting camera calibration are analyzed,and the feature extraction algorithm of two-dimensional calibration target image is studied.The advantages and disadvantages of several feature point extraction algorithms are compared.Finally,the camera calibration experiment is carried out and satisfactory results are obtained.2.Research on system calibration method of fringe reflection three-dimensional measurement system;First we introduces the calibration method of fringe reflection three-dimensional measurement system and the basic principle of fringe reflection technology.Then we analyzes the effect of calibration results on its measurement accuracy,and compares the three calibration methods respectively based on the display screen and the reference plane,based on mobiling the display screen and based on the analytical expression of the phase gradient.Finally,the influences of camera calibration parameters such as focal length and principal point on the measurement results were experimentally studied.3.Research on portable fringe projection three-dimensional measurement system;The measuring principle and system calibration method of fringe projection three-dimensional measuring system are introduced in detail.The portable fringe projection three-dimensional measuring system based on the micro projector and smart phone is studied.The overall structure design of the system is given and it is carried out through experiments and the traditional system.By contrast,the feasibility is verified.A micro fringe projection 3D measurement system based on only one smart phone is further designed.The system is equivalent to the size of one smart phone and has the advantages of being economical and portable.4.Research on dual camera calibration method in binocular vision;The basic principle of binocular vision measurement system is introduced and the method of dual camera calibration is analyzed,and meantime the basic principle of dual camera calibration is described.Finally,a dual camera calibration experiment with parallel and non-parallel optical axes of the camera is performed.5.Research on the method of eliminating the ambiguity of fringe reflection three-dimensional measurement system;We first analyzes the causes of the polysemy of fringe reflection three-dimensional measurement system and introduces the current research status of polysemy elimination methods in this thesis.Then the research on the elimination method of system placement error based on dual laser positioning is carried out.Finally the simulation and experiment are carried out to verify its feasibility.