Imaging Through Random Discrete-Scatterer Dispersive Media
Abstract
The objective of the effort was to develop a methodology which would allow enhanced signal transmission, high resolution range imaging and/or target detection through optically obscuring, dilute, discrete-scatterer media such as clouds, fog, dust and other aerosols. (A) Properties of chirped-train waveforms such as their multi-band power spectra and the resulting point spread and ambiguity functions were analyzed. Advantages of the utilization of chirped trains in "multi-spectral"imaging (i.e., imaging based on frequency sub-bands of the chirped train signal) allowing extraction of frequency dependent information with improved signal-to-noise ratio was observed. (B) Propagation of short infrared/optical pulses in dilute random media consisting of large, compared to the wavelength, scatterers was analyzed. A rigorous approach based on analytic complex-contour integration of numerically determined cut and pole singularities of the radiative transport equation solution in the Fourier space was developed. It was found that the intensity of a propagating pulse, in addition to the coherent ("ballistic") contribution and a long late-time diffusive tail, also exhibits a sharply rising early-time component that (i) can be attributed to the small-angle diffractive part of the scattering cross-section on medium particles, (ii) is attenuated proportionally to the nondiffractive rather than total cross-section, and (iii) can be extracted by high-pass filtering of the received pulse.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 27, 2015
- Accession Number
- ADA622740
Entities
People
- Elizabeth H. Bleszynski
- Marek C. Bleszynski
- Thomas Jaroszewicz