Polarimetric Hierarchical Semantic Model and Scattering Mechanism Based PolSAR Image Classification

TL;DR

This paper introduces a hierarchical semantic model for PolSAR image classification that effectively segments complex scenes into homogeneous regions by leveraging polarimetric information and a multi-level semantic approach.

Contribution

The paper proposes a novel polarimetric hierarchical semantic model (PHSM) that combines primal and middle-level semantics for improved PolSAR image segmentation.

Findings

Outperforms state-of-the-art methods in region homogeneity

Enhances edge preservation in terrain classification

Effective across different bands and sensors

Abstract

For polarimetric SAR (PolSAR) image classification, it is a challenge to classify the aggregated terrain types, such as the urban area, into semantic homogenous regions due to sharp bright-dark variations in intensity. The aggregated terrain type is formulated by the similar ground objects aggregated together. In this paper, a polarimetric hierarchical semantic model (PHSM) is firstly proposed to overcome this disadvantage based on the constructions of a primal-level and a middle-level semantic. The primal-level semantic is a polarimetric sketch map which consists of sketch segments as the sparse representation of a PolSAR image. The middle-level semantic is a region map which can extract semantic homogenous regions from the sketch map by exploiting the topological structure of sketch segments. Mapping the region map to the PolSAR image, a complex PolSAR scene is partitioned into aggregated, structural and homogenous pixel-level subspaces with the characteristics of relatively coherent terrain types in each subspace. Then, according to the characteristics of three subspaces above, three specific methods are adopted, and furthermore polarimetric information is exploited to improve the segmentation result. Experimental results on PolSAR data sets with different bands and sensors demonstrate that the proposed method is superior to the state-of-the-art methods in region homogeneity and edge preservation for terrain classification.