Analysis of Illumination Intensity in Fourier Ptychography Microscopy

Abstract

Fourier Ptychography Microscopy (FPM) is a computational imaging technique that achieves high-resolution, wide-field microscopy by combining multiple low-resolution images captured under varying illumination angles. While the method has demonstrated resolution beyond the traditional diffraction limit, its practical application remains constrained by long image acquisition times. This research investigates the limiting factors of the current 32×32 LED illumination array and explores modifications to improve illumination performance and reduce exposure time. Using optical power measurements, oscilloscope analysis, and controlled imaging trials, the study identifies multiplexing frequency and short duty cycles to be the primary factors affecting LED brightness resulting in longer capture times. Comparative experiments with custom-designed 5×5 and 7×7 matrices driven by static DC signals show a significant increase in optical power output and smoother illumination uniformity, leading to short exposure times. The findings highlight the impact of illumination stability on Fourier domain sampling and provide practical guidelines for developing LED arrays optimized for high-speed, high-fidelity FPM imaging.