Spatial Phase-Sweep: Increasing temporal resolution of transient imaging using a light source array
This addresses the need for higher temporal resolution in transient imaging for applications like light-in-flight capture, though it appears incremental as it builds on existing Time-of-Flight systems.
The paper tackles the problem of limited temporal resolution in transient imaging by proposing 'spatial phase-sweep', a technique that uses a linear array of light sources to achieve a theoretical temporal resolution of 100 Gfps, overcoming the 100 picosecond limit of current electronics.
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.