Phase unwrapping through demodulation by use of the regularized phase-tracking technique

Most interferogram demodulation techniques give the detected phase wrapped owing to the arctangent function involved in the final step of the demodula tion process. To obtain a continuous detected phase, an unwrapping process must be performed. Here we propose a phase-unwrapping technique based on a regularized phase-tracking (RPT) system. Phase unwrapping is achieved in tw o steps. First, we obtain two phase-shifted fringe patterns from the demodu lated wrapped phase (the sine and the cosine), then demodulate them by usin g the RPT technique. In the RPT technique the unwrapping process is achieve d simultaneously with the demodulation process so that the final goal of un wrapping is therefore achieved. The RPT method for unwrapping the phase is compared with the technique of least-squares integration of wrapped phase d ifferences to outline the substantial noise robustness of the RPT technique . (C) 1999 Optical Society of America.