Robust full-pose-parameter estimation for the LED array in Fourier ptychographic microscopy

TL;DR

This paper introduces a physics-based calibration method for accurately estimating the full set of pose parameters of the LED array in Fourier ptychographic microscopy, enhancing imaging quality and robustness.

Contribution

It presents a novel, comprehensive approach to calibrate all relevant LED array pose parameters using a physics-based model, improving alignment accuracy in FPM.

Findings

Effective recovery of random pose parameters demonstrated

Significant improvement in image clarity and quality

High robustness to misalignments achieved

Abstract

Fourier ptychographic microscopy (FPM) can achieve quantitative phase imaging with a large space-bandwidth product by synthesizing a set of low-resolution intensity images captured under angularly varying illuminations. Determining accurate illumination angles is critical because the consistency between actual systematic parameters and those used in the recovery algorithm is essential for high-quality imaging. This paper presents a full-pose-parameter and physics-based method for calibrating illumination angles. Using a physics-based model constructed with general knowledge of the employed microscope and the brightfield-to-darkfield boundaries inside captured images, we can solve for the full-pose parameters of misplaced LED array, which consist of the distance between the sample and the LED array, two orthogonal lateral shifts, one in-plane rotation angle, and two tilt angles, to correct illumination angles precisely. The feasibility and effectiveness of the proposed method for recovering random or remarkable pose parameters have been demonstrated by both qualitative and quantitative experiments. Due to the completeness of the pose parameters, the clarity of the physical model, and the high robustness for arbitrary misalignments, our method can significantly facilitate the design, implementation, and application of concise and robust FPM platforms.