Domain-Aware Lightweight Spectral-Grouped Convolutions for Hyperspectral Fish Freshness Classification
This study addresses the challenge of accurately classifying fish freshness from hyperspectral images, which is hindered by spectral dominance, ordinal label structure, and severe sample scarcity that limit the effectiveness of conventional deep learning approaches. To overcome these limitations, this work proposes SGNet, a lightweight network that introduces domain-aware spectral grouping convolution to decouple spectral and spatial features. By integrating depthwise separable convolution with a dual channel–spatial attention mechanism, SGNet enhances discriminative capability with minimal computational overhead. Evaluated on a self-collected dataset of salmon samples stored over 16 days, SGNet achieves a classification accuracy of 97.8% and an average absolute error of 0.64 days using only 4.75 million parameters—reducing parameter count by 5–18× compared to ResNet-50 and Vision Transformer while maintaining high accuracy and real-time performance.