In high resolution X-band POLSAR image

the water body

cement roads and the bare soil are always at low level radar backscattering signals

which is caused by no Bragg scattering phenomenon in smooth surfaces.The prevalent H/AlphaWishart and Freeman-Durden methods cannot distinguish those targets.This paper explores the improved X-band classification algorithm based on the pre-classification result for low backscattering objects in urban areas.The occurrence plane which is combined by entropy and the standard deviation of the co-pol channel diff phase is used to refine the pre-classification.The experiments show that the overall accuracy is above 80% and Kappa coefficient is higher than 0.7.The improved method improves the potential to distinguish the mixture classes of the low backscattering objects.