Abstract: Doppler correction of broadband LIDAR includes mixing, during a first time interval, a returned optical signal with an in-phase version of the transmitted signal to produce a first mixed optical signal that is detected during the first time interval to produce a first electrical signal. During a non-overlapping second time interval the returned optical signal is mixed with a quadrature version of the transmitted signal to produce a second mixed optical signal that is detected during the second time interval to produce a second electrical signal. A complex digital signal uses one of the digitized electrical signals as a real part and a different one as the imaginary part. A signed Doppler frequency shift of the returned optical signal is determined based, at least in part, on a Fourier transform of the complex digital signal. A device is operated based on the Doppler frequency shift.
Type:
Grant
Filed:
July 10, 2017
Date of Patent:
September 3, 2019
Assignee:
Blackmore Sensors and Analytics Inc.
Inventors:
Stephen C. Crouch, Krishna Rupavatharam
Abstract: Laser 3D imaging techniques include splitting a laser temporally-modulated waveform of bandwidth B and duration D from a laser source into a reference beam and a target beam and directing the target beam onto a target. First data is collected, which indicates amplitude and phase of light relative to the reference beam received at each of a plurality of different times during a duration D at each optical detector of an array of one or more optical detectors perpendicular to the target beam. Steps are repeated for multiple sampling conditions, and the first data for the multiple sampling conditions are synthesized to form one or more synthesized sets. A 3D Fourier transform of each synthesized set forms a digital model of the target for each synthesized set with a down-range resolution based on the bandwidth B.
Type:
Grant
Filed:
June 24, 2016
Date of Patent:
July 31, 2018
Assignees:
Blackmore Sensors and Analytics Inc., Montana State University
Inventors:
Stephen C. Crouch, Brant M. Kaylor, Zeb W. Barber, Randy R. Reibel