Automatic removal of phase aberration in holographic microscopy for drug sensitivity detection of ovarian cancer cells

Abstract

Real-time and long-term monitoring of the morphological changes of cells in biomedical science is highly desired. Quantitative phase imaging (QPI) obtained by various interferometric methods is the ideal tool for monitoring such processes as it allows to get quantitative information and thus assessing the right response on cell behaviors. Among QPI, digital holography (DH) in microscope configuration is a powerful tool as it is tolerant versus defocusing and for this reason is able to compensate for eventual defocusing effect during long time-lapse recording. Moreover, DH dynamic phase imaging for biological specimens has several advantages, namely non-invasive, label-free, and high-resolution. However, in DH, one of the main limitations is due to the need compensate aberrations due to the optical components in the object beam. In fact, the image of the object is inevitably embedded in aberrations due to the microscope objective (MO) and other optical components in the optical setup. Here, we propose an automatic and robust phase aberration compensation method based on a synthetic difference (SD) image process. The method is able to detect automatically object-free regions. From such regions, hologram’s aberrations can be accurately evaluated and cleaned up in the final QPI maps. Thanks to our method, temporal evolutions of cell morphological parameters were quantitatively analyzed, hence helping in studying the drug sensitivity of ovarian cancer cells. The experimental results demonstrated that the proposed method could robustly separate the object-free region from the distorted phase image and automatically compensate the total aberrations without any manual interventions, extra components, prior knowledge of the object, and optical setup.