Few-Shot Remote Sensing Scene Classification via Subspace Based on Multiscale Feature Learning

Because of the challenges associated with the difficulty of accurately labeling the remote sensing (RS) scene images and the need to identify new scene classes, few-shot learning has shown significant advantages in addressing the remote sensing scene classification (RSSC) tasks, leading to a growing interest. However, due to the scale variations of targets and irrelevant complex background in scene images, the current few-shot methods exist the following problems: the problem of the extraction capability of feature extractor in the few-shot mechanism; the problem of the separability of few-shot RS scene images classifier. To solve the above problems, an approach, called few-shot RSSC via subspace based on multiscale feature learning is introduced in this work. We first design a multiscale feature learning technique to address scale variations of the targets in the scene images. Concretely, different branches are utilized to learn scene features at various scales. The self-attention mechanism is embedded in each branch to incorporate the understanding of the global information in the different scale features. After that, a multiscale feature fusion operation, incorporating channel attention, will be devised to effectively merge the different scale features, so as to obtain a more precise feature representation of RS scene images. Furthermore, the subspace is utilized to capture the shared characteristics of each category, to reduce the impact of the complex irrelevant backgrounds in the scene images. The results of our experiments conducted on the public available RS scene datasets demonstrate the strong competitiveness of our approach.