Optimized Techniques to Reduce Speckle in SAR Images

The Synthetic Aperture Radar (SAR) is one of the most modern spaceborne sensors used to have "images" of the Earth surface; although its characteristic to be an all-weather, day-night instrument makes it particularly attractive for geoscience investigations, the speckle which affects all SAR images reduces the possibility to correctly classify crops and vegetates areas. In this paper the effect of incoherent integration on speckle reduction is described, both for independent and correlated observations (looks) of distributed targets, and two methods to improve the radiometric resolution are discussed. Results are shown for the case of 4 partially overlapped looks with Signal-to-Noise ratio variable in accordance to the azimuth antenna pattern and a trade-off between the two techniques is made.