EVALUATION OF COHERENT SCATTERERS IN HIGH-RESOLUTION POLARIMETRIC SAR IMAGERY

Pixels in SAR imagery can be grouped as those of coherent scatterers and those of distributed scatterers. Identifying coherent scatterers from distributed scatterers is of a general interest because the former are often associated with man-made targets whereas the latter are often associated with natural clutter. An ideal coherent scatter would exhibit scattering stability with respect to time, frequency, aperture angle, and polarization state. At high resolution, coherent scatterer returns may not satisfy the premise of circularly complex speckle. In this paper, we compare and evaluate the coherent scatterer detection methods based on the spectral stability among multiple sub-bands and one based on the non-circularity metric. It shows evaluating non-circularity offers a favorable option for identifying coherent scatters and accordingly demonstrates the need to be cautious on the circular speckle premise in high resolution images.