Research On High-speed Three-dimensional Surface Shape Measurement Method Based On High Frame Rate Phase Shift Sinusoidal Fringe Projection

From the first industrial revolution represented by the steam engine in the 18 th century to the current third industrial revolution characterized by digitization,our understanding of the objective world has become increasingly profound,and the level of practice has rapidly improved due to the rapid development of technology.As a typical application for observing the objective world,3D measurement technology plays a crucial role in the digitization of the objective world.This thesis focuses on the research of fast structured light 3D imaging methods based on a high-frame-rate projection module and explores the structured light 3D measurement technology based on a binocular stereo vision system.The thesis includes the following three parts:(1)Theoretical analysis of the high-frame-rate projection module.Firstly,the generation principle of binary-coded sinusoidal patterns is theoretically analyzed,and the projection modules based on liquid crystal and LED are introduced respectively.Then,the optical path structure of the projection system is designed through simulation and integrated packaging is performed.Finally,experimental verification is conducted,showing that both the liquid crystal and LED projection modules can correctly produce the phase-shifted patterns,and no secondary spectrum is observed in the frequency spectrum.(2)A high-speed measurement system based on the high-frame-rate sinusoidal pattern projection module is constructed.This system consists of a high-speed camera and an LED sinusoidal pattern projection module capable of projecting at a speed of up to 1 MHz.High-speed measurement experiments are conducted at frequencies of 1000 Hz and 2000 Hz,respectively.Phase measurement experiments are performed on both the liquid crystal and LED projection modules,with root mean square errors of 0.53 rad and 2.40 rad,respectively,compared to commercial projection devices.(3)A measurement system based on a binocular stereo vision system is established.Rapid acquisition and calibration of the binocular stereo vision system are achieved,and the research and implementation of stereo matching 3D reconstruction methods based on epipolar geometry are conducted.By combining epipolar geometry constraints and the phase characteristics of structured light measurement,stereo matching is performed to compensate for the calibration difficulties of the projection modules proposed in this paper,enabling fast matching computation and achieving 3D reconstruction.The average error of point cloud reconstruction is 1.38 mm with a relative error of 2.15%,and the angle measurement error is 2.90° with a relative error of 9.00%.