Comparison of Various Algorithms for Phase Unwrapping in Optical Phase Microscopy

Interferometric techniques belong to the standard repertoire in the field of optical metrology to give reliable quantitative results for investigating transparent objects or measuring surface displacements. Meanwhile holographic interferometric methods have also found their applications in the field of microbiology (Marquet et al., 2005) where their quantitative nature gives an advantage over phase contrast or DIC microscopy (Murphy, 2001), which yield high spatial resolution but can give only qualitative results. There exists a variety of temporal and spatial phase based interferogram analysis methods. In this paper we concentrate on phase shifting and phase demodulation techniques. Our interferometer enables us to perform both tasks in one setup simultaneously. In both applications we have the problem of unwrapping phase images (Ghiglia and Pritt, 1998) for the analysis of the recorded fringe patterns. We present an FFT based 2D unwrapping algorithm that allows a simple and fast reconstruction of the phase distribution of the objects. We apply our methods for technical and biological objects.