Towards Zero-power 3D Imaging: VLC-assisted Passive ToF Sensing

TL;DR

This paper presents a passive 3D imaging method using VLC-assisted ToF sensing that eliminates the need for active illumination, enabling low-power depth imaging through existing lighting infrastructure.

Contribution

It introduces a bistatic passive ToF imaging system synchronized via optical wireless communication, redefining image formation without active illumination.

Findings

Achieved passive depth and intensity imaging without emitted photons

Demonstrated synchronization using VLC infrastructure

Reduces optical power requirements for ToF cameras

Abstract

Passive Time-of-Flight (ToF) imaging can be enabled by optical wireless communication (OWC). The lighting infrastructure is the backbone of emerging light-based wireless communication. To this end, communication sources are used as opportunity illuminators to probe the scene, and an array of time-resolved pixels are exploited to demodulate the return, provided that the ToF camera can be externally synchronized. Our work employs a direct line-of-sight path to synchronize the camera externally. Together with the indirect path given by the reflections from the scene, this yields a bistatic configuration. Each Time-of-Flight (ToF) measurement induced a solution space of ellipsoidal shape and redefined the image formation model based on the bistatic configuration. In this demo, we showcase a passive ToF camera capable of delivering intensity and depth information in practice without emitting photons from the ToF camera. Our passive modality can eliminate built-in illumination sources, thus coping with optical power constraints, as is desired in future ToF cameras.