Multi-Aspect-Aware Bidirectional LSTM Networks for Synthetic Aperture Radar Target Recognition

The outstanding pattern recognition performance of deep learning brings new vitality to the synthetic aperture radar (SAR) automatic target recognition (ATR). However, there is a limitation in current deep learning based ATR solution that each learning process only handles one SAR image, namely learning the static scattering information, while missing the space-varying information. It is obvious that space-varying scattering information introduced in the multi-aspect joint recognition should improve the classification accuracy and robustness. In this paper, a novel multi-aspect-aware method is proposed to achieve this idea through the bidirectional long short-term memory (LSTM) recurrent neural networks-based space-varying scattering information learning. Specifically, we first select different aspect images to generate the multi-aspect space-varying image sequences. Then, the Gabor filter and three-patch local binary pattern are progressively implemented to extract comprehensive spatial features, followed by dimensionality reduction with the multi-layer perceptron network. Finally, we design a bidirectional LSTM recurrent neural network to learn the multi-aspect features with further integrating the softmax classifier to achieve target recognition. Experimental results demonstrate that the proposed method can achieve 99.9% accuracy for 10-class recognition. Besides, its anti-noise and anti-confusion performances are also better than the conventional deep learning-based methods.