Autofocusing and resolution enhancement in digital holographic microscopy by using speckle-illumination

Abstract

Sequential speckle illumination has been incorporated into digital holographic microscopy (DHM) for autofocusing and resolution enhancement. For autofocusing, the image plane is numerically determined by searching for the minimal deviation among the reconstructed images obtained by different speckle illuminations and propagating the object wave to the image plane accordingly. Furthermore, an iterative method is used to synthesize the numerical aperture from the reconstructed object waves obtained by different speckle illuminations, in order to achieve resolution enhancement. The feasibility of the proposed method is demonstrated by both simulation and experiment.