Multiplexed coded illumination for Fourier Ptychography with an LED array microscope

TLDR

Fourier Ptychography is a computational microscopy technique that produces gigapixel images with wide field of view and high phase and amplitude resolution, previously achieved by sequentially illuminating each LED to combine low‑resolution images into a higher‑bandwidth reconstruction. The study demonstrates a multiplexed illumination strategy that turns on multiple randomly selected LEDs per image. The authors replace the microscope’s illumination unit with a programmable LED array, use multiplexed illumination by turning on multiple randomly selected LEDs per image to sample different Fourier space regions, and experimentally validate the approach on a modified commercial microscope, reducing the number of images needed without compromising image quality. Compared with sequential scanning, the multiplexed strategy yields comparable image quality while reducing acquisition time and data capture by roughly an order of magnitude.

Abstract

Fourier Ptychography is a new computational microscopy technique that achieves gigapixel images with both wide field of view and high resolution in both phase and amplitude. The hardware setup involves a simple replacement of the microscope's illumination unit with a programmable LED array, allowing one to flexibly pattern illumination angles without any moving parts. In previous work, a series of low-resolution images was taken by sequentially turning on each single LED in the array, and the data were then combined to recover a bandwidth much higher than the one allowed by the original imaging system. Here, we demonstrate a multiplexed illumination strategy in which multiple randomly selected LEDs are turned on for each image. Since each LED corresponds to a different area of Fourier space, the total number of images can be significantly reduced, without sacrificing image quality. We demonstrate this method experimentally in a modified commercial microscope. Compared to sequential scanning, our multiplexed strategy achieves similar results with approximately an order of magnitude reduction in both acquisition time and data capture requirements.