Perturbative Fourier Ptychographic Microscopy for Fast Quantitative Phase Imaging

TL;DR

Perturbative Fourier ptychographic microscopy (pFPM) combines dark-field illumination and iterative algorithms to achieve fast, high-resolution, wide-field quantitative phase imaging with fewer measurements, overcoming limitations of traditional methods.

Contribution

The paper introduces pFPM, a novel extension of DPC that incorporates dark-field illumination and iterative regularization to improve resolution and speed in quantitative phase imaging.

Findings

pFPM achieves high-resolution, wide-field phase imaging with fewer measurements.

The method improves reconstruction quality over standard DPC.

Tailored annular dark-field illumination enhances image quality.

Abstract

In computational phase imaging with a microscope equipped with an array of light emitting diodes as illumination unit, conventional Fourier ptychographic microscopy achieves high resolution and wide-field reconstructions but is constrained by a lengthy acquisition time. Conversely, differential phase contrast (DPC) offers fast imaging but is limited in resolution. Here, we introduce perturbative Fourier ptychographic microscopy (pFPM). pFPM is an extension of DPC that incorporates dark-field illumination to enable fast, high-resolution, wide-field quantitative phase imaging with few measurements. We interpret DPC as the initial iteration of a Gauss-Newton algorithm with quadratic regularization and generalize it to multiple iterations and more sophisticated regularizers. This broader framework is not restricted to bright-field measurements and allows us to overcome resolution limitations of DPC. We develop tailored annular dark-field illumination patterns that align with the perturbative interpretation and lead to an improvement in the quality of reconstruction with respect to other common illumination schemes. Consequently, our methodology combines an enhanced phase reconstruction algorithm with a specialized illumination strategy and offers significant advantages in both imaging speed and resolution.