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

• Published in: Optics and laser technology 2024-03, Vol.170, p.110268, Article 110268
• Main Authors: Wang, Peng, Peng, Tao, Zhang, Shuhe, Lu, Fengya, Zhong, Zhensheng, Li, Jun, Wang, Yi, Zhou, Jinhua
• Format: Article
• Language: English
• Subjects: Diffraction phase microscopy; Phase unwrapping; Regularization; Sparse prior
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2023.110268

•We proposed a sparse prior phase unwrapping (SPUP) method with L0-norm and L1-norm regularizations to solve the wrapped phase of interferograms in diffraction phase microscopy.•The SPUP algorithm has robust denoising ability and high phase fidelity for smooth and borderline objects.•The SPUP method can be further applied to other interferometry methods, such as synthetic aperture radar, magnetic resonance imaging, and optical Doppler tomography. 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.