FPM-WSI: Fourier ptychographic whole slide imaging via feature-domain backdiffraction

TL;DR

This paper introduces FPM-WSI, a novel computational framework for whole slide imaging that uses feature-domain backdiffraction to achieve stitching-free, high-resolution, full-field-of-view microscopy, reducing artifacts and simplifying setup.

Contribution

It proposes a feature-domain backdiffraction method for Fourier ptychographic microscopy that eliminates stitching artifacts and reduces the need for precise illumination calibration.

Findings

Effective elimination of vignetting artifacts.

Reduces requirement for precise illumination knowledge.

Enables automatic blind-digital refocusing.

Abstract

Fourier ptychographic microscopy (FPM), characterized by high-throughput computational imaging, theoretically provides a cunning solution to the trade-off between spatial resolution and field of view (FOV), which has a promising prospect in the application of digital pathology. However, block reconstruction and then stitching has currently become an unavoidable procedure due to vignetting effects. The stitched image tends to present color inconsistency in different image segments, or even stitching artifacts. In response, we reported a computational framework based on feature-domain backdiffraction to realize full-FOV, stitching-free FPM reconstruction. Different from conventional algorithms that establish the loss function in the image domain, our method formulates it in the feature domain, where effective information of images is extracted by a feature extractor to bypass the vignetting effect. The feature-domain error between predicted images based on estimation of model parameters and practically captured images is then digitally diffracted back through the optical system for complex amplitude reconstruction and aberration compensation. Through massive simulations and experiments, the method presents effective elimination of vignetting artifacts, and reduces the requirement of precise knowledge of illumination positions. We also found its great potential to recover the data with a lower overlapping rate of spectrum and to realize automatic blind-digital refocusing without a prior defocus distance.