Passive 3D Time-of-Flight Imaging leveraging VLC Infrastructure

Visible light communication (VLC), as a readily available communication technology, can provide a practical and low-cost solution for power-constrained active Time-of-Flight (ToF) imaging in indoor settings. This paper demonstrates a novel passive ToF imaging concept that exploits opportunity illuminators, e.g., VLC sources. This differs from classical ToF methods, in that two parallel sensing channels are used to attain passive 3D imaging. We studied a bistatic geometry using the pulse-based (PB) ToF method. Furthermore, we explored both uniform and non-uniform sampling approaches in the time-shift domain, in order to preserve depth accuracy with a minimal number of noise-contaminated measurements. Using a matched filtering method, we attained a negligible root-mean-square error (RMSE) even for the low signal-to-noise ratio (SNR) of the measurements. We corroborate the proposed framework by conducting the first reported passive-ToF 3D imaging experiments of this kind. Our “proof-of-concept” witnessed the feasibility of VLC-enabled passive ToF, thus opening unprecedented co-design avenues with mainstream optical wireless communication (OWC) variants.