Algorithms for interpreting SAR imagery of complex building scenes

SAR images of sites containing many buildings or other structures can be difficult to interpret visually. This is because SAR signatures generated by such sites are both complex and yet often sparser than the panchromatic signatures So familiar to the human brain. It is often difficult to visually associate a given SAR signature component with a specific structure. This paper presents ongoing work aimed at developing interpretation aids for such SAR images. Specifically, the paper focuses on recently developed methods for rapidly predicting SAR signatures of buildings and then overlaying them precisely on SAR imagery as visual interpretation guides. Using 3-dimensional building models, complex multibounce SAR signatures are simulated at interactive speeds. Signatures from dominant single point or single line scatterers are similarly formed. Tradeoffs between signature simulation speed and precise signature detail are discussed. Also discussed are the sensor modeling requirements and the precision georegistration methods needed to position the simulated signatures over actual SAR imagery. The paper includes a discussion of techniques used and examples of simulated signatures overlaid on imagery using these methods. Finally, application of the SAR signature overlays and precision registration methods to image fusion is discussed.