Micro Resolution Time-of-Flight Imaging with Super heterodyne Interferometry

A technique to generate modulation frequencies as high as 1 THz using optical super heterodyne interferometry for high resolution time-of-flight depth imaging

Three dimensional imaging techniques have been widely used in both industry and academia. Time-of-flight (ToF) sensors offer a promising method of 3D imaging due to compact size and low complexity. However, state-of-the-art ToF sensors only have depth resolutions of centimeters due to limitations in the modulation frequencies that can be used. In this paper, we propose a technique to generate modulation frequencies as high as 1 THz using optical super heterodyne interferometry. Our proposed system provides great flexibility in imaging range and resolution. We experimentally demonstrate an increase in depth resolution by an order of magnitude relative to currently available commercial ToF cameras.

Publications

Micro Resolution Time-of-Flight Imaging

Fengqiang Li, Florian Willomitzer, P Rangarajan, Mohit Gupta, Andreas Velten, Oliver Cossairt

Proc. ICCP 2018

pdf
@INPROCEEDINGS{Li_ICCP_2018,
author={F. Li and F. Willomitzer and P. Rangarajan and M. Gupta and A. Velten and O. Cossairt},
booktitle={2018 IEEE International Conference on Computational Photography (ICCP)},
title={SH-ToF: Micro resolution time-of-flight imaging with superheterodyne interferometry},
year={2018},
volume={},
number={},
pages={1-10},
keywords={image resolution;image sensors;light interferometry;SH-ToF;ToF cameras;ToF sensors;academia;depth resolution;industry;modulation frequencies;optical superheterodyne interferometry;three dimensional imaging techniques;time-of-flight sensors;Adaptive optics;Frequency modulation;Laser beams;Optical imaging;Optical interferometry;Optical sensors},
doi={10.1109/ICCPHOT.2018.8368473},
ISSN={},
month={May},}

High-depth-resolution Range Imaging with Multiple-wavelength Superheterodyne Interferometry using 1550-nm Lasers

Fengqiang Li, Joshua Yablon, Andreas Velten, Mohit Gupta, Oliver Cossairt

Applied Optics 2017

pdf
@article{Li:17,

author = {Fengqiang Li and Joshua Yablon and Andreas Velten and Mohit Gupta and Oliver Cossairt},

journal = {Appl. Opt.},

keywords = {Imaging systems; Lasers and laser optics; Interferometric imaging ; Diode lasers; Imaging systems; Imaging techniques; Laser beam combining; Phase modulation; Range imaging},

number = {31},

pages = {H51–H56},

publisher = {OSA},

title = {High-depth-resolution range imaging with multiple-wavelength superheterodyne interferometry using 1550-nm lasers},

volume = {56},

month = {Nov},

year = {2017},

url = {http://ao.osa.org/abstract.cfm?URI=ao-56-31-H51},

doi = {10.1364/AO.56.000H51},

abstract = {Lasers and laser diodes are widely used as illumination sources for optical imaging techniques. Time-of-flight (ToF) cameras with laser diodes and range imaging based on optical interferometry systems using lasers are among these techniques, with various applications in fields such as metrology and machine vision. ToF cameras can have imaging ranges of several meters, but offer only centimeter-level depth resolution. On the other hand, range imaging based on optical interferometry has depth resolution on the micrometer and even nanometer scale, but offers very limited (sub-millimeter) imaging ranges. In this paper, we propose a range imaging system based on multi-wavelength superheterodyne interferometry to simultaneously provide sub-millimeter depth resolution and an imaging range of tens to hundreds of millimeters. The proposed setup uses two tunable III-V semiconductor lasers and offers leverage between imaging range and resolution. The system is composed entirely of fiber connections except the scanning head, which enables it to be made into a portable device. We believe our proposed system has the potential to tremendously benefit many fields, such as metrology and computer vision.},

}