An Adaptive Defocus Three-Dimensional Measurement Method Based on Tabu Search and Combined Gray Code

Tong Jia,Gaohui Cao,Dong Xu,Miao Hu,Hongyu Wang

doi:10.1109/access.2020.2966761

Abstract

In the field of 3D measurement, digital fringe projection (DFP) techniques have become a hotspot of research and application due to its non-contact, low cost and high resolution characteristics, but the gamma effect caused by projector seriously affects the 3D measurement quality of DFP techniques. This paper presents a Tabu Search optimization algorithm to generate high-quality binary patterns, which are projected and defocused to obtain the wrap phase, which can avoid the influence of gamma effect on phase quality. Secondly, in order to solve the problem that it is difficult to maintain the degree of defocus, a defocus adaptive optimization system is built. Finally, in order to reduce the influence of projector defocus on Gray code phase unwrapping, a combined Gray code method is proposed, which can accurately unwrap the wrap phase and reduce the interference of the color of object on phase unwrapping. The experimental results show that the proposed method improves the 3D measurement results of DFP techniques and improves the robustness.

Highlights

With the rapid development of technologies such as 3D vision and virtual reality, it is more and more important to accurately reconstruct three-dimensional (3D) shape of objects
I, j refers to the coordinate index of the pixel, Rrefers to an ideal sinusoidal pattern, which refers to a sinusoidal pattern that is projected onto the surface of the object without being affected by the gamma effect
R refers to the defocused binary pattern, d is the difference of the pixel values between the ideal sinusoidal patterns and the defocused binary patterns, m, n refers to the length and width of the image, and Rmse is the mean square error between R and R, that is the evaluation value of R

Summary

Introduction

With the rapid development of technologies such as 3D vision and virtual reality, it is more and more important to accurately reconstruct three-dimensional (3D) shape of objects. Among the methods of three-dimensional measurement, optical methods are commonly used due to their non-contact properties. Digital fringe projection (DFP) techniques [1], [2] are popular for their low cost and flexibility. A DFP system uses a computer to generate sinusoidal fringe patterns that are projected on to an object by a projector. A camera captures the fringe patterns distorted by the object surface geometry, and a phase analysis algorithm is used to reconstruct a three-dimensional (3D) shape. The phase accuracy will directly affect the 3D reconstruction result of the measured object

Methods

Results

Conclusion