A study of material identification using SAR

Abstract

Abstract-We investigate the feasibility of using synthetic aperture radar (SAR) data to identify materials at each pixel in a SAR image. A fundamental concept underlying our approach is to extract the dispersion of the reflectivity at each pixel by dividing the data into several frequency sub-bands. We first compute synthetic radar data using parameters that are characteristic of a typical wide-band SAR system operating in a spotlight mode and illuminating several scattering regions that differ in their frequency response. Secondly, we process the data by subdividing the full data set into frequency sub-bands thereby extracting the dispersion at each pixel. Third and finally, we perform the material identification using a rudimentary classification analysis. The approach described herein offers a new method for planning experimental data collections for the purpose of material identification through SAR image formation.

Synthetic Aperture Imaging of Direction- and Frequency-Dependent Reflectivities

“…Data segmentation is a natural idea that has been used before for synthetic aperture imaging of frequency dependent reflectivities [21,11]. Here we use it for estimating the direction dependence of the reflectivity, as well.…”

“…The reconstruction of frequency dependent reflectivities with synthetic aperture radar has been considered in [8], where Doppler effects are shown to be useful in inversion, and in [21,11], where data are segmented over frequency sub-bands, and then images are formed separately, for each data subset. Data segmentation is a natural idea, and we show here how to use it for reconstructing both frequency and direction dependent reflectivities.…”

Imaging frequency-dependent reflectivity from synthetic-aperture radar

“…In this case, the transmitted frequency band can be split up into intervals around these frequencies, and separate images formed from each band. If, in addition, the β (Doppler terms) are negligible, then (29) and (30) can be written…”

“…One approach [29,33] to obtaining both frequency and spatial information is simply to divide the radar frequency band into sub-bands, and then form images from the individual bands. These images are necessarily of lower resolution, but taken together, they provide information about the frequency dependence of the target radar reflectivity.…”

A Multiple Measurement Vector Approach to Synthetic Aperture Radar Imaging

“…SAR imaging of frequency-dependent reflectivities has been studied in [16,35,34], using either Doppler effects, or data segmentation over frequency sub-bands. Data segmentation is a natural idea for imaging both frequency and direction dependent reflectivities that are regular enough so that they can be approximated as piecewise constant functions over properly chosen frequency sub-bands and cones of angles of incidence (i.e., sub-apertures).…”