Macroscopic Interferometry: Rethinking Depth Estimation with Frequency-Domain Time-of-Flight

Achuta Kadambi1   Jamie Schiel1   Ramesh Raskar1

1MIT Media Lab   

IEEE CVPR 2016, Las Vegas

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).

Technical Paper

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.


Prototype for Multi-Depth Imaging

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 for hardware fabrication questions.


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"


Achuta Kadambi
MIT Media Lab