Improved Sigma Filter for Speckle

heLeesigmafilterwasdevelopedin1983basedonthesimpleconceptoftwo-sigmaprobability,anditwasrea-sonablyeffectiveinspecklefiltering.However,deficiencieswerediscoveredinproducingbiasedestimationandinblurringanddepressingstrongreflectedtargets.Theadvancementofsyntheticapertureradar(SAR)technol