Shadow enhancement in SAR imagery

Shadow cast by features on ground can be an important aid in object classification in synthetic aperture radar (SAR) images. Synthetic aperture imaging causes a fundamental limitation to shadow clarity due to the fact that the illuminator is moved during the data collection. This leads to a blend of echo and shadow, or geometrical fill-in in the shadow region. The fill-in is most dominant for wide beam synthetic aperture imaging systems. By treating the shadow as a moving target and compensating for the motion during the synthetic aperture imagery, we avoid the geometrical shadow fill-in. This new technique, referred to as the fixed focus shadow enhancement (FFSE) can be used directly as an imaging method on raw SAR data or as a post processing technique on the complex SAR image. In this paper, we demonstrate the FFSE technique on publicly available SAR data.