An Adaptive Decomposition Approach with Dipole Aggregation Model for Polarimetric SAR Data

A Hybrid Polarimetric Target Decomposition Algorithm with Adaptive Volume Scattering Model

Previous studies have shown that scattering mechanism ambiguity and negative power issues still exist in model-based polarization target decomposition algorithms, even though deorientation processing is implemented. One possible reason for this is that the dynamic range of the model itself is limited and cannot fully satisfy the mixed scenario. To address these problems, we propose a hybrid polarimetric target decomposition algorithm (GRH) with a generalized volume scattering model (GVSM) and a random particle cloud volume scattering model (RPCM). The adaptive volume scattering model used in GRH incorporates GVSM and RPCM to model the volume scattering component of the regions dominated by double-bounce scattering and the surface scattering, respectively, to expand the dynamic range of the model. In addition, GRH selects the volume scattering component between GVSM and RPCM adaptively according to the target dominant scattering mechanism of fully polarimetric synthetic aperture radar (PolSAR) data. The effectiveness of the proposed method was demonstrated using AirSAR dataset from San Francisco. Comparison studies were carried out to test the performance of GRH over several target decomposition algorithms. Experimental results show that the GRH outperforms the algorithms we tested in this study in decomposition accuracy and reduces the number of negative power pixels, demonstrating that the GRH can significantly avoid mechanism ambiguity and negative power issues.

A Comparative Study on Classification Features between High-Resolution and Polarimetric SAR Images through Unsupervised Classification Methods

Feature extraction and comparison of synthetic aperture radar (SAR) data of different modes such as high resolution and full polarization have important guiding significance for SAR image applications. In terms of image and physical domain for higher spatial resolution single-polarized and coarser spatial resolution quad-pol SAR data, this paper analyzes and compares the feature extraction with unsupervised classification methods. We discover the correlation and complementarity between high-resolution image feature and quad-pol physical scattering information. Therefore, we propose an information fusion strategy, that can conduct unsupervised learning of the landcover classes of SAR images obtained from multiple imaging modes. The medium-resolution polarimetric SAR (PolSAR) data and the high-resolution single-polarized data of the Gaofen-3 satellite are adopted for the selected experiments. First, we conduct the Freeman–Durden decomposition and H/alpha-Wishart classification method on PolSAR data for feature extraction and classification, and use the Deep Convolutional Embedding Clustering (DCEC) algorithm on single-polarized data for unsupervised classification. Then, combined with the quantitative evaluation by confusion matrix and mutual information, we analyze the correlation between characteristics of image domain and physics domain and discuss their respective advantages. Finally, based on the analysis, we propose a refined unsupervised classification method combining image information of high-resolution data and physics information of PolSAR data, that optimizes the classification results of both the urban buildings and the vegetation areas. The main contribution of this comparative study is that it promotes the understanding of the landcover classification ability of different SAR imaging modes and also provides some guidance for future work to combine their respective advantages for better image interpretation.

Guaranteed Robust Tensor Completion via ∗L-SVD with Applications to Remote Sensing Data

This paper conducts a rigorous analysis for the problem of robust tensor completion, which aims at recovering an unknown three-way tensor from incomplete observations corrupted by gross sparse outliers and small dense noises simultaneously due to various reasons such as sensor dead pixels, communication loss, electromagnetic interferences, cloud shadows, etc. To estimate the underlying tensor, a new penalized least squares estimator is first formulated by exploiting the low rankness of the signal tensor within the framework of tensor ∗L-Singular Value Decomposition (∗L-SVD) and leveraging the sparse structure of the outlier tensor. Then, an algorithm based on the Alternating Direction Method of Multipliers (ADMM) is designed to compute the estimator in an efficient way. Statistically, the non-asymptotic upper bound on the estimation error is established and further proved to be optimal (up to a log factor) in a minimax sense. Simulation studies on synthetic data demonstrate that the proposed error bound can predict the scaling behavior of the estimation error with problem parameters (i.e., tubal rank of the underlying tensor, sparsity of the outliers, and the number of uncorrupted observations). Both the effectiveness and efficiency of the proposed algorithm are evaluated through experiments for robust completion on seven different types of remote sensing data.