Widefield lensless endoscopy via speckle-correlations

TL;DR

This paper introduces a novel lensless endoscopic imaging method that uses speckle correlations to achieve high-resolution, variable-distance imaging through a fiber bundle without distal optics, and is insensitive to fiber bending.

Contribution

It presents a computational, single-shot imaging technique that overcomes limitations of traditional fiber-optic endoscopes, enabling miniaturization and flexible imaging without distal optics or focus mechanisms.

Findings

Achieves diffraction-limited resolution

Insensitive to fiber bending

Allows variable working distance imaging

Abstract

Flexible fiber-optic endoscopes provide a minimally-invasive solution for imaging at depths beyond the reach of conventional microscopes. Current endoscopes require focusing and/or scanning mechanisms at the distal end, which limit miniaturization and frame-rate, and induce aberrations. Alternative lensless solutions are based on adaptive wavefront-correction, but are extremely sensitive to fiber bending. Here, we demonstrate a novel endoscopic approach, which enables single-shot imaging at a variable working distance through a conventional fiber bundle, without the use of any distal optics. Our approach computationally retrieves the object image from a single speckle pattern transmitted through the bundle, exploiting phase information preserved through inherent angular speckle correlations. Unlike conventional fiber-bundle endoscopes, the resulting image is unpixelated, the resolution is diffraction-limited, objects can be imaged at variable working distance, and the technique is completely insensitive to fiber bending. Since no optical elements are required, miniaturization is limited only by the bundle diameter.