Spatial Phase-Sweep: Increasing temporal resolution of transient imaging using a light source array

TL;DR

This paper introduces spatial phase-sweep, a technique that leverages a light source array to surpass electronic temporal resolution limits in transient imaging, achieving potentially 100 Gfps in temporal resolution.

Contribution

The paper presents a novel spatial phase-sweep method that exploits light speed and a light source array to significantly enhance transient imaging temporal resolution.

Findings

Prototype implementation demonstrates improved temporal resolution.

Achieves theoretical 100 Gfps in transient imaging.

Utilizes a linear array of light sources for phase-shift control.

Abstract

Transient imaging or light-in-flight techniques capture the propagation of an ultra-short pulse of light through a scene, which in effect captures the optical impulse response of the scene. Recently, it has been shown that we can capture transient images using commercially available Time-of-Flight (ToF) systems such as Photonic Mixer Devices (PMD). In this paper, we propose `spatial phase-sweep', a technique that exploits the speed of light to increase the temporal resolution beyond the 100 picosecond limit imposed by current electronics. Spatial phase-sweep uses a linear array of light sources with spatial separation of about 3 mm between them, thereby resulting in a time shift of about 10 picoseconds, which translates into 100 Gfps of transient imaging in theory. We demonstrate a prototype and transient imaging results using spatial phase-sweep.