Ptychographic non-line-of-sight imaging for depth-resolved visualization of hidden objects

TL;DR

This paper introduces ptychographic NLOS (pNLOS), a novel depth-resolved imaging technique that uses coded ptychography to visualize hidden objects with high resolution and fidelity beyond line-of-sight.

Contribution

The paper presents a new NLOS imaging method leveraging coded ptychography to achieve depth-resolved visualization of obscured objects.

Findings

High-resolution imaging of hidden objects achieved

Depth information successfully recovered

Effective imaging through complex wall surfaces

Abstract

Non-line-of-sight (NLOS) imaging enables the visualization of objects hidden from direct view, with applications in surveillance, remote sensing, and light detection and ranging. Here, we introduce a NLOS imaging technique termed ptychographic NLOS (pNLOS), which leverages coded ptychography for depth-resolved imaging of obscured objects. Our approach involves scanning a laser spot on a wall to illuminate the hidden objects in an obscured region. The reflected wavefields from these objects then travel back to the wall, get modulated by the wall's complex-valued profile, and the resulting diffraction patterns are captured by a camera. By modulating the object wavefields, the wall surface serves the role of the coded layer as in coded ptychography. As we scan the laser spot to different positions, the reflected object wavefields on the wall translate accordingly, with the shifts varying for objects at different depths. This translational diversity enables the acquisition of a set of modulated diffraction patterns referred to as a ptychogram. By processing the ptychogram, we recover both the objects at different depths and the modulation profile of the wall surface. Experimental results demonstrate high-resolution, high-fidelity imaging of hidden objects, showcasing the potential of pNLOS for depth-aware vision beyond the direct line of sight.