Filtering optical wrapped phase images algorithm

• Published in: Optical engineering 2017-11, Vol.56 (11), p.111704-111704
• Main Authors: Medina, Orlando M, Estrada, Julio C, López, Yolanda Y
• Format: Article
• Language: English
• ISSN: 0091-3286; 1560-2303
• DOI: 10.1117/1.OE.56.11.111704

In optical interferometry, noise and distortions in the recovered wrapped phase are very common, and their nature is inherent to the quality and visibility of the fringe patterns that modulate the phase. Filtering these phase imperfections from the wrapped phase is not straightforward since we cannot directly apply filters without damaging their information, that is, its modulus 2π phase jumps. However, having a way to filter noise and distortions from the wrapped phase is desirable and very important because, at the end, the filtered phase is closer to the expected, errors are reduced, and the unwrapping task can be less complex. We propose a modulus 2π filtering method to remove noise and distortions directly from the wrapped phase without damaging its information. The presented method is a global filtering process, but we use the local frequencies from the wrapped phase in such a way that each pixel is tuned to its instant frequency.