光谱成像技术研究室知识库

Structured light 3D reconstruction technology has the advantages of non-contact, low cost and high reliability, and is widely used in industrial parts defect detection, cultural relics 3D digitization and other fields. As the core part of structured light, coding method is the key element to obtain 3D scene information, which directly affects the accuracy of 3D reconstruction. The combination of gray coding and phase shifting is a typical method for 3D shape measurement. However, due to the complexity of sinusoidal fringe calculation, and the fringe pattern boundary cannot be strictly aligned, there is a step change problem, which limits the application of this method in the field of real-time high-speed three-dimensional measurement. In this paper, the phase shift method of triangular wave and gray coding are combined to measure the 3D morphology. The triangular wave function only uses two raster images and the phase information can be obtained by simple intensity ratio calculation. The binary defocus technique can shorten the projection time, but it blurs the edge boundary of gray code and aggravates the step problem of reconstruction of object surface. In order to solve this problem, the complementary gray code whose fringe width is half of the sinusoidal fringe period is used to correct the period deviation. The experimental results show that the proposed method can reduce the number of fringe projection, simplify the calculation steps and shorten the time of data processing, so it is feasible. © 2021 SPIE.