Research On 3D Measurement System Of Structured Light Applicable For Fast 3D Shape Measurement

Using digital fringe projection method for 3D measurement,because has the advantages of non-contact,wide measurement range,high precision,high stability characteristics,has broad prospects for development in the field of industrial heritage quality control,3D modeling,virtual reality,biomedical,is a popular direction in the current domestic research workers of surgery.According to the nonlinear effects of structure light 3D reconstruction process and obtain the absolute phase of the problem,this paper research and analysis deeply,and constructed the structure light 3D measurement system for measuring fast and strong adaptability.This paper mainly focuses on the following three aspects:1)The nonlinear error correction of structure light is studied,and two solutions are proposed to overcome the nonlinear error.First of all,this chapter proposes a two two level grayscale synthesis method of fringe width modulation fringe grayscale level three single pulse,eliminating the structure light nonlinear calibration,realized in the three level pulse width modulation fringe grayscale under defocus structured light 3D reconstruction.Then,this paper presents a method of using the frequency domain digital filtering method for the structural nonlinear correction.Theoretical analysis,simulation and experimental verification are carried out for the two solutions.2)Proposed a structure of two yuan light ladder phase new encoding method,the encoding method can accurately determine the level of projection grating period,compared with the traditional step phase encoding method,to reduce the number of fringe projection under the same conditions,improve the measuring speed,without considering the influence of color projection multi channel color aliasing the next,if the fringe modulation of color channels,can further improve the measurement speed.The binarization encoding stripes,while retaining the advantages of traditional step phase measurement of a fast,according to different sinusoidal grating,adjust the number of phase-shift steps and step phase sub area,with the traditional phase encoding step do not have the flexibility.After this chapter on the theoretical simulation and real experimental results of 3D reconstruction,3D reconstruction with high accuracy,the simulation and experimental results verify the validity of 3D measurement by this method.3)To build an experimental system of structured light 3D reconstruction is used in this paper,a detailed description from two aspects of hardware and software of the system;study the phase depth mapping and image correction,the experimental results before and after correction of 3D reconstruction contrast table picture distortion caused by camera calibration effectively the correction.