An Improved Synthesis Phase Unwrapping Method Based on Three-Frequency Heterodyne

Abstract

An improved three-frequency heterodyne synthesis phase unwrapping method is proposed to improve the measurement accuracy through phase difference and phase sum operations. This method can reduce the effect of noise and increase the equivalent phase frequency. According to the distribution found in the phase difference calculation process, the Otsu segmentation is introduced to judge the phase threshold. The equivalent frequency obtained from the phase sum is more than those of all projected fringe patterns. In addition, the appropriate period combinations are also studied. The simulations and related experiments demonstrate the feasibility of the proposed method and the ability to improve the accuracy of the measurement results further.

Fringe Projection Profilometry Based on Saturated Fringe Restoration in High Dynamic Range Scenes

“…The basic principle is to project periodically changing sinusoidal fringe patterns onto the measured object, and the object’s height will modulate the fringes and cause distortion. Then, a camera is utilized to capture the distorted fringe patterns, and the phase of the object, which represents its height, is obtained using phase retrieval methods [ 2 , 3 , 4 , 5 ]. Generally, FPP is very effective for Lambertian objects.…”