What are Fading and Speckle?
Fading and speckle are the inherent “noise-like” processes which degrade the quality of an image Fading is due to variation in the time delay of the reflected energy caused by multiple targets in a resolution cell with range variations differing by less than a wavelength. Reflecting surfaces are rarely uniform. For example, even a homogeneous forest has variations in the shape, height and variation of its canopy. These small differences cause local tonal variations which are known as speckle. Using independent data sets to estimate the same ground patch, by average independent samples, can effectively reduce the effects of fading and speckle. This can be done by: Multiple-look filtering, separates the maximum synthetic aperture into smaller sub- apertures generating independent looks at target areas based on the angular position of the targets. Therefore looks are different Doppler frequency bands. Averaging (incoherently) adjacent pixels. Reducing these effects enhances radiometric re
