Quantitative Phase and Amplitude Imaging Using Differential-Interference Contrast (DIC) Microscopy

摘要

We present an extension of the development of an alternating minimization (AM) method' for the computationof a specimen's complex transmittance function (magnitude and phase) from DIC images. The ability to extractboth quantitative phase and amplitude information from two rotationally-diverse DIC images (i.e., acquired byrotating the sample) extends previous efforts in computational DIC microscopy that have focused on quantitativephase imaging only. Simulation results show that the inverse problem at hand is sensitive to noise as well asto the choice of the AM algorithm parameters. The AM framework allows constraints and penalties on themagnitude and phase estimates to be incorporated in a principled manner. Towards this end, Green and DePierro's "log-cosh" regularization penalty is applied to the magnitude of differences of neighboring values ofthe complex-valued function of the specimen during the AM iterations. The penalty is shown to be convex inthe complex space. A procedure to approximate the penalty within the iterations is presented. In addition, amethodology to pre-compute AM parameters that are optimal with respect to the convergence rate of the AMalgorithm is also presented. Both extensions of the AM method are investigated with simulations.