Study on phase unwrapping algorithms in interferogram processing

Abstract

Phase unwrapping problem has raised great interest in last decade because it is encountered in many image signal processing fields. For ideal wrapped phase maps, the unwrapping work is straightforward. In practice, the data obtained includes a high proportion of noise; perhaps speckle noise, electronic noise, and sampling aliasing, and so on. Unwrapping of noisy interferogram still presents a challenge. Filtering work could distort the phase data of the processed map and cause filtering aliasing. In order to use phase unwrapping algorithm with reliable to test and analyze, and simplicity to program and implement. Special request has been analyzed about the elimination of noise in wrapped phase field. A scheme for pre-unwrapping filter is proposed. Noise-reduction were discussed that can filter wrapped phase data without smoothing the edges of phase jumps. It has proved that the pre-unwrapping could strengthen the interference fringe clarity during noise elimination, and it has good retention of original information. The use of this filter allows unwrapping of noisy phase maps with simple and fast Fourier unwrapping algorithms, thus avoiding the need for complex unwrapping routines.