Structured Illumination Microscopy Image Reconstruction Algorithm

TLDR

Structured illumination microscopy (SIM) is a high‑speed super‑resolution technique that doubles spatial resolution, yet most reconstruction improvements focus on a single aspect and overlook key elements, and the literature lacks a comprehensive review of the theoretical background. This study aims to consolidate the essential theoretical details of the SIM algorithm in one place and to release an open‑source reconstruction code, OpenSIM, that lets users interactively adjust parameters and observe their effects on reconstructed images. OpenSIM implements the full SIM reconstruction pipeline, including accurate determination of illumination pattern phase shift, modulation factor, object power spectrum estimation, Wiener filtering with object spectrum, and merging of overlapping frequency components, allowing users to vary these parameters interactively.

Abstract

Structured illumination microscopy (SIM) is a very important super-resolution microscopy technique, which provides high speed super-resolution with about two-fold spatial resolution enhancement. Several attempts aimed at improving the performance of SIM reconstruction algorithm have been reported. However, most of these highlight only one specific aspect of the SIM reconstruction -- such as the determination of the illumination pattern phase shift accurately -- whereas other key elements -- such as determination of modulation factor, estimation of object power spectrum, Wiener filtering frequency components with inclusion of object power spectrum information, translocating and the merging of the overlapping frequency components -- are usually glossed over superficially. In addition, most of the work reported lie scattered throughout the literature and a comprehensive review of the theoretical background is found lacking. The purpose of the present work is two-fold: 1) to collect the essential theoretical details of SIM algorithm at one place, thereby making them readily accessible to readers for the first time; and 2) to provide an open source SIM reconstruction code (named OpenSIM), which enables users to interactively vary the code parameters and study it's effect on reconstructed SIM image.