# Incoherent lensless imaging via coherency back-propagation

## TL;DR

This paper demonstrates a lensless imaging method that reconstructs scenes by numerically back-propagating measured complex coherence functions, enabling object detection without traditional lenses.

## Contribution

It introduces a novel incoherent imaging technique using coherency back-propagation with digital micromirror device-based coherence measurements.

## Key findings

- Successful reconstruction of object sizes and positions from coherence data
- Imaging achieved without lenses despite lack of shadows in intensity
- Method applicable to partially coherent light scattering

## Abstract

The two-point complex coherence function constitutes a complete representation for scalar quasi-monochromatic optical fields. Exploiting dynamically reconfigurable slits implemented with a digital micromirror device, we report on measurements of the complex two-point coherence function for partially coherent light scattering from a `scene' comprising one or two objects at different transverse and axial positions with respect to the source. Although the intensity shows no discernible shadows in absence of a lens, numerically back-propagating the measured complex coherence function allows estimating the objects' sizes and locations -- and thus the reconstruction of the scene.