SpectralTrain: A Universal Framework for Hyperspectral Image Classification
Organizations: School of Medical Information, Wannan Medical University, Wuhu, China · University of Chinese Academy of Sciences, Beijing, China · The Chinese University of Hong Kong, Hong Kong, China · Northeastern University, Liaoning, China
Abstract
Hyperspectral image (HSI) classification typically involves large-scale data and computationally intensive training, which limits the practical deployment of deep learning models in real-world remote sensing tasks. This study introduces SpectralTrain, a universal, architecture-agnostic training framework that enhances learning efficiency by integrating curriculum learning (CL) with principal component analysis (PCA)-based spectral downsampling. By gradually introducing spectral complexity while preserving essential information, SpectralTrain enables efficient learning of spectral -- spatial patterns at significantly reduced computational costs. The framework is independent of specific architectures, optimizers, or loss functions and is compatible with both classical and state-of-the-art (SOTA) models. Extensive experiments on three benchmark datasets -- Indian Pines, Salinas-A, and the newly introduced CloudPatch-7 -- demonstrate strong generalization across spatial scales, spectral characteristics, and application domains. The results indicate consistent reductions in training time by 2-7x speedups with small-to-moderate accuracy deltas depending on backbone. Its application to cloud classification further reveals potential in climate-related remote sensing, emphasizing training strategy optimization as an effective complement to architectural design in HSI models. Code is available at https://github.com/mh-zhou/SpectralTrain.
Figures & tables
| Dataset | Data unit | Bands | Classes | ||
|---|---|---|---|---|---|
| Indian Pines | scene | 200 | 16 | 22 | |
| Salinas-A | scene | 204 | 6 | 18 | |
| CloudPatch-7 | 380 patches from 28 scenes | 462 | 7 | 30 |
| Stage | Equivalent-budget interval | Active PCs | ||
|---|---|---|---|---|
| 1 | 1–100 | 10 | 0.45 | 10 |
| 2 | 101–200 | 20 | 0.70 | 10 |
| 3 | 201–300 | 30 | 1.00 | – |
| Settings | OA (%) | AA (%) | Kappa | Time (s/epoch) |
|---|---|---|---|---|
| Ours (PCA curriculum) | 99.02 | 99.04 | 0.99 | 8.00 |
| + Savitzky–Golay | 98.82 | 98.87 | 0.99 | 8.00 |
| + Gaussian | 98.80 | 98.84 | 0.99 | 11.00 |
| + TV Denoising | 98.87 | 98.91 | 0.99 | 8.00 |
| Model | Current SOTA Training Ravikumar et al. (2022) | SpectralTrain | ||||||
|---|---|---|---|---|---|---|---|---|
| Time (s/epoch) | OA (%) | AA (%) | Kappa | Time (s/epoch) | OA (%) | AA (%) | Kappa | |
| ResNet-34 | 113 | 98.55 | 98.59 | 0.98 | 66 | 98.20 | 98.05 | 0.98 |
| ADGAN | 664 | 98.96 | 98.91 | 0.98 | 298 | 98.28 | 98.10 | 0.98 |
| MetaFormer | 77 | 98.93 | 98.98 | 0.99 | 17 | 98.95 | 98.94 | 0.99 |
| ConvNeXt-T | 269 | 99.06 | 99.14 | 0.99 | 94 | 99.15 | 99.18 | 0.99 |
| SQS | 356 | 99.30 | 99.30 | 0.99 | 254 | 98.17 | 98.11 | 0.98 |
| Dimensionality Reduction Method | OA (%) | AA (%) | Kappa | Time (s/epoch) |
|---|---|---|---|---|
| PCA | 99.15 | 99.18 | 0.99 | 8.00 |
| UMAP | 99.36 | 99.39 | 0.99 | 8.00 |
| ICA | 98.89 | 98.86 | 0.99 | 8.00 |
| Loss Function | OA (%) | AA (%) | Kappa | Time (s/epoch) |
|---|---|---|---|---|
| Cross Entropy Loss | 98.96 | 99.01 | 0.99 | 8.00 |
| Multi-Label Soft Margin Loss | 98.96 | 98.97 | 0.99 | 8.00 |
| Binary Cross Entropy with Logits | 99.02 | 99.04 | 0.99 | 8.00 |
| Optimizer | OA (%) | AA (%) | Kappa | Time (s/epoch) |
|---|---|---|---|---|
| AdamW | 99.15 | 99.18 | 0.99 | 8.00 |
| AdamMini | 98.95 | 98.99 | 0.99 | 8.00 |
| SGD | 98.82 | 98.83 | 0.99 | 8.00 |
| Epoch | OA (%) | AA (%) | Kappa |
|---|---|---|---|
| 50 | 98.67 | 98.67 | 0.99 |
| 100 | 98.80 | 98.88 | 0.99 |
| 200 | 98.87 | 98.93 | 0.99 |
| 300 | 99.15 | 99.18 | 0.99 |
| 400 | 98.98 | 98.98 | 0.99 |
| 500 | 98.86 | 98.94 | 0.99 |
| # | Settings | OA (%) | AA (%) | Kappa |
|---|---|---|---|---|
| S1 | Seed = 1 | 98.87 | 98.85 | 0.98 |
| S2 | Seed = 10 | 98.80 | 98.87 | 0.98 |
| S3 | Seed = 42 | 98.96 | 98.99 | 0.99 |
| S4 | Seed = 123 | 98.96 | 98.94 | 0.99 |
| S5 | Seed = 666 | 98.83 | 98.92 | 0.98 |
| S6 | Mean Std |
| Model | OA (%) | AA (%) | Kappa |
|---|---|---|---|
| ADGAN | 97.37 | 94.59 | 0.97 |
| MetaFormer | 94.34 | 93.31 | 0.94 |
| ConvNeXt-T | 98.72 | 99.12 | 0.99 |
| SQS | 94.02 | 97.30 | 0.94 |
| 3D-ConvSST | 90.95 | 84.56 | 0.91 |
| RCNN | 98.33 | 98.71 | 0.98 |
| Model | OA (%) | AA (%) | Kappa |
|---|---|---|---|
| ADGAN | 92.69 | 94.23 | 0.93 |
| MetaFormer | 94.10 | 94.22 | 0.94 |
| ConvNeXt-T | 98.09 | 97.86 | 0.98 |
| SQS | 95.02 | 95.37 | 0.95 |
| 3D-ConvSST | 97.35 | 96.65 | 0.97 |
| RCNN | 98.09 | 98.02 | 0.98 |
| Model | OA (%) | AA (%) | Kappa |
|---|---|---|---|
| ADGAN | 98.28 | 98.10 | 0.98 |
| MetaFormer | 98.95 | 98.94 | 0.99 |
| ConvNeXt-T | 99.15 | 99.18 | 0.99 |
| SQS | 98.17 | 98.11 | 0.98 |
| 3D-ConvSST | 99.02 | 99.04 | 0.99 |
| RCNN | 99.44 | 99.42 | 0.99 |
Appendix figures & tables4 assets
Supplementary material from the paper’s appendix.
Appendix
Hyperspectral Image Classification
Hyperspectral image classification assigns land-cover, material, or biological labels using the spectral and spatial information in image pixels.
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