Coded time of flight cameras: sparse deconvolution to address multipath interference and recover time profiles
Name
Raskar_Coded time.pdf
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21.66 MB
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Author(s)
Kadambi, Achuta
Whyte, Refael
Bhandari, Ayush
Streeter, Lee
Barsi, Christopher
Dorrington, Adrian
Raskar, Ramesh
Date Issued
November 2013
Journal
ACM Transactions on Graphics
Publisher
Association for Computing Machinery
Citation
Kadambi, Achuta, Refael Whyte, Ayush Bhandari, Lee Streeter, Christopher Barsi, Adrian Dorrington, and Ramesh Raskar. “Coded Time of Flight Cameras.” ACM Transactions on Graphics 32, no. 6 (November 1, 2013): 1–10.
Version
Author's final manuscript
Abstract
Time of flight cameras produce real-time range maps at a relatively low cost using continuous wave amplitude modulation and demodulation. However, they are geared to measure range (or phase) for a single reflected bounce of light and suffer from systematic errors due to multipath interference.
We re-purpose the conventional time of flight device for a new goal: to recover per-pixel sparse time profiles expressed as a sequence of impulses. With this modification, we show that we can not only address multipath interference but also enable new applications such as recovering depth of near-transparent surfaces, looking through diffusers and creating time-profile movies of sweeping light.
Our key idea is to formulate the forward amplitude modulated light propagation as a convolution with custom codes, record samples by introducing a simple sequence of electronic time delays, and perform sparse deconvolution to recover sequences of Diracs that correspond to multipath returns. Applications to computer vision include ranging of near-transparent objects and subsurface imaging through diffusers. Our low cost prototype may lead to new insights regarding forward and inverse problems in light transport.
MIT Department
Massachusetts Institute of Technology. Media Laboratory
Program in Media Arts and Sciences (Massachusetts Institute of Technology)
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1145/2508363.2508428
