A phase unwrapping method with the sparse prior for diffraction phase microscopy

Phase unwrapping is widely used in interferometry. In the typical least square (LS) method, the noise in the wrapped phase cannot be removed. An improved algorithm based on total variation (TV) imposes L1-norm on the image gradient to improve the sparsity. However, it may lead to over-sparsity, and the unwrapped phase will be compressed if the penalty term is overlarge. In this study, we proposed a sparse prior phase unwrapping (SPUP) algorithm to solve the wrapped phase of interferograms of diffraction phase microscopy (DPM). Since DPM has a unique sample sparsity in the imaging field of high-power objectives, the L0-norm and L1-norm regularizations are introduced into the SPUP process. The results verify the strong denoising ability and high phase fidelity of the proposed SPUP method. Moreover, the uneven background noise and phase shifting of DPM interferograms could be corrected, demonstrating the great potential of the SPUP method in various interferometry measurements.

Automated summary

In this study, a sparse prior phase unwrapping (SPUP) algorithm was proposed to solve the wrapped phase problem in interferograms. By introducing L0-norm and L1-norm regularizations, the SPUP method exhibited strong denoising ability and high phase fidelity. It could effectively correct uneven background noise and phase shifting, demonstrating great potential in various interferometry measurements.