Multiple-wavelength-scanning-based phase unwrapping method for digital holographic microscopy

A phase unwrapping approach based on multiple-wavelength scanning is presented for digital holographic microscopy. It unwrapped the ambiguous phase image layer by layer by synthesizing the extracted continuous components from a set of multiple phase images obtained by varying the optical wavelength, where the discontinuities occur at different places and the phase speckle noise presents various distributions in state. The total time for data acquisition is approximately 22 min for 10 wavelengths. The simulation and experimental results demonstrate that the proposed method has a more accurate calculation and better counteraction of phase noise compared with those of previously reported approaches. In addition, the wrapped phase image of the object containing the steps has also been unwrapped successfully. (C) 2014 Optical Society of America