Recent Advances in Computational Time-of-Flight Imaging

—Time-of-Flight (ToF) cameras are 3D imaging de vices that capture the geometry of a scene, exploiting the fact that the travel time of photons is directly linked to the traveled distance. This kind of sensor holds great promise in emerging application areas, but a number of shortcomings compromise its deployment. Specifically, we focus on the relatively large power consumption compared to conventional cameras, the limited range at which depth can be accurately estimated, and measurement distortions produced by the harmonic content of the modulation/demodulation waveforms and the multi-path interference. In this work, we present recent advances in compu tational ToF imaging aiming to surpass these limitations, enabling passive operation indoors, long-range operation outdoors, and the realization of single-shot multi-frequency continuous-wave operation with minimal harmonic distortion. Passive operation is attained by exploiting opportunity sources of modulated light, such as LiFi or Visible Light Communications (VLC) modules. Independently, gains in operative range can be obtained by means of ultrashort pulse shaping combined with low-density coded demodulation. Accurate Fourier sampling with minimal harmonic distortion is attained by inducing custom resonant effects in the ToF pixels. Initial evaluation results prove the potential of these computational 3D imaging approaches to bypass the aforementioned limitations.

keywords: 3D imaging, passive ToF, VLC, single-shot multi frequency