Improving Sar Automatic Target Recognition Using Simulated Images Under Deep Residual Refinements

In recent years, convolutional neural networks (CNNs) have been successfully applied for automatic target recognition (ATR) in synthetic aperture radar (SAR) data. However, it is challenging to train a CNN with high classification accuracy when labeled data is limited. This is often the case with SAR ATR in practice, because collecting large amounts of labeled SAR data is both difficult and expensive. Using a simulator to generate SAR images offers a possible solution. Unfortunately, CNNs trained on simulated data may not be directly transferable to real data. In this paper, we introduce a method to refine simulated SAR data based on deep residual networks. We learn a refinement function from simulated to real SAR data through a residual learning framework, and use the function to refine simulated images. Using the MSTAR dataset, we demonstrate that a CNN-based SAR ATR system trained on simulated data under residual network refinements can yield much higher classification accuracy as compared to a system trained on simulated images, and so can training on real data augmented with these simulated data under refinements compared to training with real data alone.