Three-dimensional tomographic imaging camera based on compressive sensing

摘要

A detection apparatus and method for FMCW LIDAR employ signals that are modified so that low-cost and low-speed photodetector arrays, such as CCD or CMOS cameras, can be employed for range detection. The LIDAR is designed to measure the range to one or more targets and includes a single mode swept frequency laser (SFL), whose optical frequency is varied with time, as a result of which, a target beam which is reflected back by the one or more targets is shifted in frequency from a reference beam by an amount that is proportional to the relative range to the one or more targets. The reflected target beam(s) is/are combined with the reference beam and detected by the photodetector array. In the case of a sparse number of targets to be detected, Compressive Sensing (CS) techniques can be employed by a processor to reduce the number of measurements necessary to determine the range of each target.

主权项

1. An apparatus for detecting the range of one or more targets comprising:
a swept frequency laser source for generating an output launched laser beam whose frequency varies as a function of time over a predetermined optical bandwidth; an interferometer for receiving said launched laser beam and dividing said laser beam into a target beam and a reference beam, said interferometer including a first, target arm for directing said target beam to one or more targets whose range is to be determined, receiving a one or more reflected target beams from said one or more targets; a second, reference arm for transmitting said reference beam; and a combiner for combining said reference beam in said reference arm with said one or more reflected target beams in said target arm and forming a combined output beam; a modulator for modulating at least one of said target beam and said reference beam; a waveform generator for applying one of a plurality of non-sinusoidal waveforms to said modulator such that said combined output beam contains at least range information for each of said one or more targets; a photodetector for receiving said combined output beam and generating an output measurement in response thereto; and a processor for controlling operation of said swept frequency laser source and said waveform generator so that a sequence of said non-sinusoidal waveforms is applied to said modulator by said waveform generator and said photodetector generates a sequence of output measurements, each of which corresponds to one of said non-sinusoidal waveforms applied to said modulator; and wherein said processor receives said sequence of output measurements from said photodetector and is programmed to determine the range of said one or more targets by using compressive sensing techniques with said sequence of output measurements.