A Multiscale Spatial–Spectral Prototypical Network for Hyperspectral Image Few-Shot Classification

Abstract

Due to the complex environment of hyperspectral image (HSI) gathering area, it is difficult to obtain a large number of labeled samples for HSI. Therefore, how to effectively achieve the HSI few-shot classification is a hot spot of current research. Prototypical network (PN) is one of the most classical few-shot learning algorithms, which has been widely employed for few-shot image classification and few-shot object detection. However, existing PN-based algorithms for HSI only utilize the single-scale spatial-spectral feature extracted from the last layer, ignoring the semantic information with different scales contained in the other layers. To solve this problem, a novel multi-scale spatial-spectral prototypical network (MSSPN) is proposed in this letter. The contribution of this letter is threefold. Firstly, a multi-scale spatial-spectral feature extraction algorithm based on ladder structure is proposed to effectively achieve the integration of spatial-spectral features with different scales. Secondly, with the theory of ladder-structure-based extraction algorithm, we design a multi-scale spatial-spectral prototype representation, which is suggested to be more robust and effective in the multi-scale spatial-spectral metric space. Finally, our proposed MSSPN has the advantage of expandability, and can be easily applied for the other PN-based few-shot learning methods. The experimental results on HSI few-shot classification indicate that our proposed MSSPN algorithm can achieve higher accuracy than the representative HSI classifiers and the existing PN-based algorithms.