Extrapolated speckle-correlation imaging

TL;DR

This paper introduces a novel speckle-correlation imaging technique that extrapolates speckle correlations to expand the imaging field of view through thick scattering media, overcoming the limitations of the memory effect.

Contribution

The authors develop a new method to extend speckle-correlation imaging capabilities by estimating correlation decay, enabling imaging through media with limited memory effect.

Findings

Successfully reconstructed point sources behind scattering media.

Demonstrated larger field of view compared to conventional methods.

Validated the approach through numerical and experimental results.

Abstract

Imaging through scattering media is a longstanding issue in a wide range of applications, including biomedicine, security, and astronomy. Speckle-correlation imaging is promising for non-invasively seeing through scattering media by assuming shift-invariance of the scattering process called the memory effect. However, the memory effect is known to be severely limited when the medium is thick. Under such a scattering condition, speckle-correlation imaging is not practical because the correlation of the speckle decays, reducing the field of view. To address this problem, we present a method for expanding the field of view of single-shot speckle-correlation imaging by extrapolating the correlation with a limited memory effect. We derive the imaging model under this scattering condition and its inversion for reconstructing the object. Our method simultaneously estimates both the object and the decay of the speckle correlation based on the gradient descent method. We numerically and experimentally demonstrate the proposed method by reconstructing point sources behind scattering media with a limited memory effect. In the demonstrations, our speckle-correlation imaging method with a minimal lensless optical setup realized a larger field of view compared with the conventional one. This study will make techniques for imaging through scattering media more practical in various fields.