Few-Shot SAR Target Recognition Based on Deep Kernel Learning

Deep learning methods have achieved state-of-the-art performance on synthetic aperture radar (SAR) target recognition tasks in recent years. However, obtaining sufficient SAR images for training these deep learning methods is costly in time and labor. This paper focuses on recognizing targets with a few training samples, that is, few-shot target recognition. We combine deep neural networks’ powerful feature representation capabilities with the nonparametric flexibility of Gaussian processes (GPs) and propose a few-shot recognition model based on deep kernel learning. Deep neural networks map input samples into a low-dimensional embedding space. GPs employ a family of kernel functions to measure the similarity between embedded samples and classify them. During training, the model builds diverse related tasks to learn kernel functions with parameters shared across few-shot tasks. These learned kernel functions define common prior knowledge that can be transferred to unseen tasks. During testing, the model can recognize novel tasks with a few samples based on learned kernel functions. We conducted extensive experiments on a widely-used real SAR dataset to evaluate the model’s effectiveness. The test results demonstrate that our model is superior to several recently proposed few-shot recognition methods.