Computational optical sectioning in Fresnel incoherent correlation holography.

Fresnel incoherent correlation holography (FINCH) is a widely used incoherent digital holography technique. FINCH has a higher lateral resolution but a lower axial resolution compared to those of direct imaging methods with the same numerical aperture. The low axial resolution problem of FINCH was addressed by developing sectioning FINCH methods implemented by pixel-by-pixel electronic scanning of a phase pinhole to achieve sectioning capability in FINCH, mimicking a conventional confocal microscope. The above approach requires not only an additional spatial light modulator for electronic scanning but also time-consuming data acquisition and processing. In this study, for the first time, to the best of our knowledge, we developed a fully computational sectioning method for FINCH. This computational optical sectioning FINCH (COS-FINCH) exploits the axial intensity and phase characteristics of FINCH holograms and first and second order derivatives of axial intensity distributions to identify the object planes, extract information, and achieve sectioning. Extensive simulation studies and results of preliminary experimental studies are presented.