The Effect of Synthetic Aperture Radar Image Resolution on Target Discrimination
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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This research details the effect of spatial resolution on target discrimination in Synthetic Aperture Radar SAR images. Multiple SAR image chips containing targets and non-targets are used to test a baseline Automatic Target Recognition ATR system with reduced spatial resolution obtained by lowering the pixel count or synthesizing a degraded image. The pixel count is lowered by averaging groups of adjoining pixels to form a new single value. The degraded image is synthesized by low-pass filtering the image frequency space and then lowering the pixel count. A two parameter Constant False Alarm Rate CFAR detector is tested, and three different types of feature spaces size, contrast, and texture are used to train a linear classifier. The results are scored using the Area Under the Receiver Operator Characteristic AUROC curve. The CFAR detector is shown to perform better at lower resolution. All three feature sets together performed well with degradation of resolution separately the sets had different performances. The texture features performed best because they do not rely on the number of pixels on the target, while the size features performed worst for the same reason. The contrast features yielded improved performance when the resolution was slightly reduced.
- Active and Passive Radar Detection and Equipment
- Target Direction, Range and Position Finding