Improved phase-unwrapping method using geometric constraints

TL;DR

This paper introduces a simplified and faster phase-unwrapping method for digital fringe projection that avoids complex calibration and additional fringe patterns, effectively overcoming limitations of previous approaches.

Contribution

The proposed method eliminates the need for system calibration and low-frequency fringe patterns, streamlining the process and enhancing speed while maintaining accuracy.

Findings

Successfully overcomes phase unwrapping failures with large frequency ratios

Reduces calibration complexity and processing time

Demonstrates improved robustness and efficiency in experiments

Abstract

Conventional dual-frequency fringe projection algorithm often suffers from phase unwrapping failure when the frequency ratio between the high frequency and the low one is too large. Zhang et.al. proposed an enhanced two-frequency phase-shifting method to use geometric constraints of digital fringe projection(DFP) to reduce the noise impact due to the large frequency ratio. However, this method needs to calibrate the DFP system and calculate the minimum phase map at the nearest position from the camera perspective, these procedures are are relatively complex and more time-cosuming. In this paper, we proposed an improved method, which eliminates the system calibration and determination in Zhang's method,meanwhile does not need to use the low frequency fringe pattern. In the proposed method,we only need a set of high frequency fringe patterns to measure the object after the high frequency is directly estimated by the experiment. Thus the proposed method can simplify the procedure and improve the speed. Finally, the experimental evaluation is conducted to prove the validity of the proposed method.The results demonstrate that the proposed method can overcome the main disadvantages encountered by Zhang's method.