US 12,154,194 B2
Coherent optical sensor with sparse illumination
David Millar, Lexington, MA (US); Okan Atalar, Stanford, CA (US); Keisuke Kojima, Weston, MA (US); Toshiaki Koike-Akino, Belmont, MA (US); Pu Wang, Cambridge, MA (US); and Kieran Parsons, Cambridge, MA (US)
Assigned to Mitsubishi Electric Research Laboratories, Inc., Cambridge, MA (US)
Filed by Mitsubishi Electric Research Laboratories, Inc., Cambridge, MA (US)
Filed on Jul. 10, 2020, as Appl. No. 16/925,680.
Prior Publication US 2022/0012926 A1, Jan. 13, 2022
Int. Cl. G06T 11/00 (2006.01); G01B 9/02091 (2022.01)
CPC G06T 11/005 (2013.01) [G01B 9/02091 (2013.01); G06T 2207/10081 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for a target image reconstruction, comprising:
emitting stepped frequency waveforms having different constant frequencies at different periods of time;
modulating the stepped frequency waveforms into frequency ranges each having a first frequency and a second frequency, wherein each of the stepped frequency waveforms is increased from the first frequency to the second frequency based on a range function, wherein the modulated stepped frequency waveforms have a sparsity factor, wherein the sparsity factor is defined as a number of wavelengths multiplied by a bandwidth per wavelength, divided by a total measurement bandwidth, wherein the sparsity factor is determined so as to be less than 1;
transmitting the modulated stepped frequency waveforms continuously to a target and accepting reflection of the modulated stepped frequency waveforms reflected from the target;
interfering the modulated stepped frequency waveforms and the reflection of the modulated stepped frequency waveforms to produce beat signals of interferences between the modulated stepped frequency waveforms and the reflection of the modulated stepped frequency waveforms; and
reconstructing an image of the target from the beat signals.