Organizations: Istanbul Technical University, Informatics Institute, Maslak 34469, İstanbul, Türkiye · Istanbul Esenyurt University, Faculty of Business and Management Sciences, Department of Management Information Systems, Esenyurt, 34517, İstanbul, Türkiye
Feature extraction for hyperspectral image classification is conventionally addressed using rigid tensor decompositions that fail to capture complex spatio-spectral interdependencies, or heavily parameterized convolutional neural networks that are computationally expensive. To overcome these limitations, this work introduces the Holistic Multivariance Decomposition (HMD) framework as a novel, end-to-end differentiable neural network layer. By explicitly separating independent single mode variations from cooperative higher dimensional interactions via learnable, matrix valued supports, the proposed HMD-0, HMD-1 and HMD-2 approximants are optimized jointly with a downstream classifier via backpropagation. Comprehensive evaluations across three benchmark HS datasets demonstrate that the higher level HMD layers achieve superior classification accuracy compared to classical learnable tensor baselines, including Tucker, Canonical Polyadic, and Tensor Train decompositions. Furthermore, HMD-1 and HMD-2 achieve a generalization capacity and training stability comparable to standard 2D and 3D-CNNs while requiring significantly fewer feature extractor parameters. These results demonstrate that the HMD framework provides a structurally robust substitute for traditional convolution in multidimensional HS image classification, offering high parameter efficiency and stability throughout the optimization process.
Figures & tables
Dataset
Sensor
Spatial Size
Spectral Bands
Classes
Indian Pines
AVIRIS
145×145
200
16
Pavia University
ROSIS
610×340
103
9
Loukia
Hyperion
250×1376
176
14
Table 1: Summary of the HS datasets used in this study.
Figure 1: Ground truth classification maps for the three benchmark HS datasets, from left to right: Indian Pines, Pavia University and Loukia. Black pixels in all images represent unlabelled background regions excluded from training and evaluation.
Figure 2: Schematic representation of the comparative deep learning pipeline for HS image classification. The architecture highlights the eight interchangeable feature extraction layers including the proposed HMD family, classical tensor models, and CNN baselines feeding into an identical, shared classifier head.
Method
OA (%)
AA (%)
F1 (macro)
κ
HMD-0
94.20
94.67
0.9421
0.9339
HMD-1
99.85
99.90
0.9975
0.9983
HMD-2
99.41
99.64
0.9935
0.9933
Tucker
90.88
90.52
0.9110
0.8960
CP
74.93
64.56
0.6297
0.7159
TT
98.05
98.12
0.9825
0.9777
Table 2: Test-set classification performance on Indian Pines. Best value in bold ; second-best underlined .
Method
OA (%)
AA (%)
F1 (macro)
κ
HMD-0
78.87
70.78
0.7017
0.7229
HMD-1
98.11
97.31
0.9691
0.9749
HMD-2
99.31
98.91
0.9882
0.9909
Tucker
86.40
74.52
0.6981
0.8175
CP
89.61
82.16
0.8374
0.8590
TT
65.31
59.32
0.5191
0.5438
Table 3: Test-set classification performance on Pavia University. Best value in bold ; second-best underlined .
Method
OA (%)
AA (%)
F1 (macro)
κ
HMD-0
79.34
70.77
0.7190
0.7554
HMD-1
91.23
87.86
0.8985
0.8950
HMD-2
94.82
90.99
0.9292
0.9384
Tucker
73.27
71.33
0.6737
0.6823
CP
80.27
62.78
0.6490
0.7605
TT
78.71
71.94
0.7342
0.7409
Table 4: Test-set classification performance on Loukia. Best value in bold ; second-best underlined .
Rank
Method
OA (%)
AA (%)
F1
κ
Parameters
1
HMD-2
97.85
96.51
0.9703
0.9742
908
2
HMD-1
96.40
95.02
0.9550
0.9561
908
3
2D-CNN
94.90
93.15
0.9449
0.9400
12,768
4
3D-CNN
91.24
87.25
0.8723
0.8963
1,032
5
HMD-0
84.13
78.74
0.7876
0.8041
908
6
Tucker
83.51
78.79
0.7609
0.7986
908
Table 5: Mean performance across the three datasets, ranked by mean overall accuracy, alongside mean feature-extractor parameter count.
Figure 3: Sensitivity analysis of Overall Accuracy (OA) and Average Accuracy (AA) with respect to the subspace dimensionality reduction parameter ( r ) on the Indian Pines dataset.
Figure 4: Sensitivity analysis of Overall Accuracy (OA) and Average Accuracy (AA) with respect to the subspace dimensionality reduction parameter ( r ) on the Pavia University dataset.
Figure 5: Sensitivity analysis of Overall Accuracy (OA) and Average Accuracy (AA) with respect to the subspace dimensionality reduction parameter ( r ) on the Loukia dataset.
Figure 6: Training/validation accuracy and loss curves, all eight methods, Indian Pines dataset.
Figure 7: Training/validation accuracy and loss curves, all eight methods, Pavia University dataset.
Figure 8: Training/validation accuracy and loss curves, all eight methods, Loukia dataset.
Method
Formula
Indian Pines
Pavia University
Loukia
HMD-0 *
r(n1+n2+n3)
1,110
625
990
HMD-1 *
r(n1+n2+n3)
1,110
625
990
HMD-2 *
r(n1+n2+n3)
1,110
625
990
Tucker *
r(n1+n2+n3)
1,110
625
990
CP *
R(n1+n2+n3)
1,110
625
990
TT
n1R1+R1n2R2+R2n3R3
5,330
2,905
4,730
Table 6: Closed-form feature-extractor parameter counts by method and dataset, at the rank/filter configuration used throughout this study ( r=5 ; TT: R1=R2=R3=5 ; 2D-CNN: k=3 , f1=8 , f2=16 ; 3D-CNN: k=3 , f1=4 , f2=8 ). Indian Pines: n3=200 ; Pavia University: n3=103 ; Loukia: n3=176 .
Hyperspectral image (HSI) classification remains challenging due to high spectral dimensionality, redundancy, and limited labeled data. Although convolutional neural networks (CNNs) and Vision Transformers (ViTs) achieve strong performance by exploiting spectral-spatial information and long-range dependencies, they often incur high computational cost and large model size, limiting practical use. To address these limitations, a unified hybrid framework, termed ConvVitMamba, is proposed for efficient HSI classification. The architecture integrates three components: a multiscale convolutional feature extractor to capture local spectral, spatial, and joint patterns; a Vision Transformer based tokenization and encoding stage to model global contextual relationships; and a lightweight Mamba inspired gated sequence mixing module for efficient content-aware refinement without quadratic self-attention. Principal Component Analysis (PCA) is used as preprocessing to reduce redundancy and improve efficiency. Experiments on four benchmark datasets, including Houston and three UAV borne QUH datasets (Pingan, Qingyun, and Tangdaowan), demonstrate that ConvVitMamba consistently outperforms CNN, Transformer, and Mamba based methods while maintaining a favorable balance between accuracy, model size, and inference efficiency. Ablation studies confirm the complementary contributions of all components. The results indicate that the proposed framework provides an effective and efficient solution for HSI classification in diverse scenarios. The source code is publicly available at https://github.com/mqalkhatib/ConvVitMamba
Mohammed Q. Alkhatib
College of Engineering and IT, University of Dubai, Dubai 14143, United Arab Emirates
Hyperspectral imaging is widely used in remote sensing and engineering. Therefore, research on its classification methods is crucial. While CNN and Transformer-based methods have advanced, they still face locality constraints and high computational complexity. To address these issues, we propose an innovative hyperspectral image classification model, MSCM-net. Specifically, first of all, a model architecture combining multi-scale CNN and Mamba is proposed. It consists of a multi-scale feature extraction module (MCSE) and multiple stacked Mamba blocks, which integrates the local feature extraction capability of multi-scale CNN and the long sequence modeling advantage of Mamba. Secondly, the proposed MCSE module consists of multi-scale convolution and SENet. Convolution kernels of different scales extract local information with different receptive fields, enhancing the fusion of spatial and spectral information. Meanwhile, the SENet enables the model to automatically learn the importance of each channel in the multi-scale features. Furthermore, we also propose a dual-branch feature aggregation module, which further effectively extracts and integrates the spectral information contained in the central pixel and the spatial information in the surrounding pixels. Our model has undergone numerous experiments on three widely used benchmark datasets. The experimental results show that MSCM-net can achieve advanced classification performance while reducing computational complexity.
Jianjun Chen, Linlin Wang, Lifang Chang +4
Qingdao University of Technology, Qingdao, 266520, China · Nanyang Technological University, Singapore, 639798, Singapore
This work presents a data-efficient variant of the Attention-Based Dual-Branch Complex Feature Fusion Network (CFFN) for hyperspectral image classification. The proposed model, termed DE-CFFN, retains the original two-stream structure: the Real-Valued Neural Network (RVNN) processes standard hyperspectral patches, while the Complex-Valued Neural Network (CVNN) handles their Fourier-transformed counterparts. The main contribution of this work lies in the feature extraction process and architectural enhancement. Factor Analysis is used for dimensionality reduction, offering improved latent feature representation over Principal Component Analysis. Additionally, both the RVNN and CVNN streams are structurally modified by successively halving the number of filters in the 3D convolutional layers to reduce complexity. The outputs of both branches are concatenated and passed through a Squeeze and Excitation (SE) block to enhance joint feature representation. Evaluated on the Pavia University and Salinas datasets, DE-CFFN achieves classification performance comparable to CFFN, while significantly reducing model size, memory consumption, and inference latency, making it suitable for real-time hyperspectral imaging applications.
Maitreya Shelare, Atharva Satam, Poonam Sonar +1
Department of Electronics and Telecommunication, Rajiv Gandhi Institute of Technology, University of Mumbai, India