Research On Three-dimensional Imaging Precision Using Phase Shifting

Three-dimensional imaging measurement technology based on Phase shifting method with non-contact,fast measurement speed and easy to realize the automation is more and more popular,has been widely used in various fields,such as mechanical engineering,virtual reality,robot guidance and reverse engineering etc.With the increasing demand,how to effectively find the factors that affect the accuracy of imaging and propose solutions to improve the accuracy of measurement is becoming more and more important.In this paper,three-dimensional imaging is realized by phase shifting method,and the data processing method of imaging is determined.The factors that affect the accuracy of imaging are simulated and the causes of accuracy are proposed.At the same time,the three-dimensional imaging experiment is completed.First of all,this paper summarized the achievements of three-dimensional imaging using phase shifting method both at home and abroad,and the factors that affect imaging accuracy are analyzed,which provide a reference for the research of this paper.Secondly,the imaging principle of three-dimensional imaging using phase shifting was determined.Based on the principle of scanning projection with a MEMS mirror,method of three-step phase shifting and phase unwrapping method,we established the imaging system mathematical model using camera imaging principle and coordinate transformation.At the same time,the error and precision measurement methods were analyzed,and the error assessment method was proposed.Combined with the principle of imaging and data processing methods,we proposed the research project of various factors,which influence the accuracy of imaging.Then,we simulated the imaging process,researched on the error caused by the uniformity of the line light source using line source of semiconductor laser as the light source,Powell prism as a linear prism,the width of laser beam,Gaussian modulation,the noise,the image saturation,the tooling debugging precision and light intensity transitivity of the optical lens.The main factors affecting the imaging accuracy were determined by comparing the effects of various factors on the imaging accuracy.And feasible methods for achieving high precision imaging were proposed.Finally,we established the three-dimensional imaging measurement system based on the imaging principle,considering the actual measurement requirements,designed the control signal.Then,we measured a plane,a model of face plaster andthe distance of cartons.The root mean square error of the plane imaging measurement is 2.2612mm;the face plaster image reduction can clearly distinguish the facial morphology;the distance between three cartons is reduced,and the reduction accuracy is in the order of centimeters.The research results of imaging factors were verified by three-dimensional imaging experiments.