This paper repurposes the microscopic technique of Frequency-Domain OCT to a macroscopic technique, Frequency ToF. Both techniques encode optical time of flight in the frequency of the received waveform. For short optical paths (top row), the received signal in the primal-domain is lower in frequency than that of longer optical paths (bottom row).
Macroscopic Interferometry, CVPR 2016 [PDF] [PDF Low Res]
 |
A form of meter-scale, macroscopic interferometry is proposed using conventional time-of-flight (ToF) sensors. Today, ToF sensors use phase-based sampling, where the phase delay between emitted and received, high-frequency signals encodes distance. This paper examines an alterna- tive ToF architecture, inspired by micron-scale, microscopic interferometry, that relies only on frequency sampling: we refer to our proposed macroscopic technique as Frequency- Domain Time of Flight (FD-ToF). The proposed architec- ture offers several benefits over existing phase ToF systems, such as robustness to phase wrapping and implicit resolu- tion of multi-path interference, all while capturing the same number of subframes. A prototype camera is constructed to demonstrate macroscopic interferometry at meter scale.
A computational camera is constructed to validate macroscopic interferometry (see the architecture in the top figure). Courtesy of Jamie Schiel, a DIY guide is available It is not trivial to rebuild this camera, but Jamie has put all the source code and hardware design filese up online. Please email schiel@mit.edu for hardware fabrication questions.
@inproceedings{CVPR16_Kadambi,
author = "Achuta Kadambi and Jamie Schiel and Ramesh Raskar,
title = "Macroscopic Interferometry: Rethinking Depth Estimation with Frequency-Domain Time-of-Flight",
booktitle = "Conference on Computer Vision and Pattern Recognition (CVPR)",
year = "2016"
}