White light phase shifting interferometric microscopy with whole slide imaging for quantitative analysis of biological samples.

In this paper, we demonstrate the white light phase shifting interferometer employed as whole slide scanner and phase profiler for determining qualitative and quantitative information over large field-of-view (FOV). Experiments were performed on human erythrocytes and MG63 Osteosarcoma cells. Here, we have recorded microscopic images and phase shifted white light interferograms simultaneously in a stepped manner. Sample slide is translated in transverse direction such that there exists a correlation between the adjacent frames, and they were stitched together using correlation functions. Final stitched image has a FOV of 0.24 × 1.14 mm with high resolution ~0.8 μm. Circular Hough transform algorithm is implemented to the resulting image for cell counting and five-step phase shifting algorithm is utilised to retrieve the phase profiles over a large FOV. Further, this technique is utilised to study the difference between normal and anaemic erythrocytes. Significant changes are observed in anaemic cells as compared to normal cells.