Algorithm based on the 1-norm character of interferograms for quantitative differential interference imaging

Abstract

Differential interference contrast (DIC) microscopy is widely used as a high-contrast imaging method for observing transparent biological samples. However, the absence of fringes in DIC images results in phase gradients that cannot be effectively extracted by most phase-shift algorithms, limiting its application in quantitative detection. Therefore, we propose an algorithm based on the 1-norm character of interferograms that can accurately extract phase shifts from a series of interferograms with less than 1/2 fringes. We improved this algorithm by combining the calculated phase shift with the least-squares fitting method to further extract the phase and applied it to quantitative DIC imaging. In contrast to the conventional algorithm, this algorithm can extract the phase gradient in DIC images with unknown phase shifts, thereby eliminating the computational error in the conventional algorithm introduced by imprecise phase shifts. Simulations and experiments demonstrated that the proposed algorithm can perform accurate phase gradient extraction.