Distance Learning-Based Prototypical Network With Multi-Domain Adaptation for Few-Shot Hyperspectral Medical Image Classification

Hyperspectral imaging (HSI) holds immense potential for medical diagnostics by capturing tissue-specific spectral signatures that facilitate precise disease detection. However, effective HSI classification in clinical settings is hindered by two main challenges: (i) the severe lack of labelled medical HSI samples constrains model training. Prototypical networks, as a few-shot learning paradigm, have been adopted to address label scarcity. However, current Euclidean-based prototypical methods typically assume equal feature variance and spherical distributions, while ignoring intraclass covariance and spectral correlations; (ii) significant domain shifts across heterogeneous medical HSI datasets undermine model generalisation, impair multi-domain interpretability, and force expensive per-dataset retraining. To overcome these limitations, we propose a novel distance-learning-based prototypical network with multi-domain adaptation for few-shot hyperspectral medical image classification. First, by embedding a class-covariance-aware Mahalanobis metric within the prototypical block, our module adapts similarity measures to each class's intrinsic spectral-spatial covariance and scale variations, thereby enhancing prototype robustness under severe label scarcity and significantly reducing misclassification compared with existing few-shot networks. Secondly, we introduce the domain-aware adapter block designed to address domain shift and multi-domain variability by dynamically fusing shared spectral-spatial representations with domain-specific characteristics via spectral integration and switchable adapters. We undertook extensive experiments on three publicly available hyperspectral medical datasets: skin dermoscopy, multidimensional choledochal, and in-vivo brain dataset. Compared to state-of-the-art classifiers, the proposed method achieved excellent performance on all three datasets, paving the way for generalisable HSI solutions in clinical workflows and biomedical research.