Handbook of Biomedical Optics

Phase Imaging Microscopy: Beyond Dark-Field, Phase Contrast, and Differential Interference Contrast Microscopy 493

A nal important distinction between phase contrast and

DIC modalities is their response to features that fall outside the

depth of eld of the microscope objective (i.e., their response

to optical defocus aberrations). Phase contrast images of thick

objects are particularly prone to defocus artifacts in which out-

of-focus regions are visible as blurred features superimposed

on those that are in focus. In addition, defocused features can

exhibit a contrast reversal (inversion of bright and dark image

regions) that further complic ...