Dual-Frequency Phase Unwrapping Method for anti-Jump Errors of Wrapped Phase

Abstract

The accuracy of stripe structured light three-dimensional measurement is greatly improved with the development of hardware and image processing technology. However, the fault tolerance and anti-jamming ability of complex measured objects need to be improved. First, by aiming at the problem of large error caused via wavelength position jump in phase unwrapping, the shortcomings of single-frequency phase unwrapping method were analyzed, a dual-frequency phase unwrapping method was proposed, and its mathematical model was established. Second, the error tolerance was analyzed near the dual-frequency phase hopping point, and the maximum error tolerance value is 0.25δ. In the environment of interference and noninterference, the three-dimensional measurement experiment shows that the mathematical model of dual-frequency phase unwrapping and the theoretical correctness of error analysis. Its measurement accuracy and anti-interference ability are higher than those of single-frequency phase unwrapping. Also, it can suppress the gross error caused by wavelength dislocation effectively, and the operation is simple. Aiming at three-dimensional measurement and reconstruction of highly complex surface with self-occlusion, the local reconstructed has high accuracy, and the reconstructed surface is smooth. It corresponds to the real measured surface and has good anti-interference performance.

Keywords:

• Three-dimensional measurement
• stripe structured light
• wrapped phase
• phase unwrapping
• dual-frequency

Additional information

Funding

This work was financially supported by 2019 Hei Long Jiang Postdoctoral Foundation Project (Grant No. LBH-Z19165), 2019 Guangdong Regular Colleges and Universities Characteristic Innovation Projects (Grant No. 2019GKTSCX026), 2020 Special fund for science and technology innovation strategy of Guangdong Province (Grant No. pdjh2020a0933) and 2020 Guangdong Polytechnic high level talents research start-up fund Project.