Deep neural networks have achieved strong performance in image classification tasks due to their ability to learn complex patterns from high-dimensional data. However, their large computational and memory requirements often limit deployment on resource-constrained platforms such as remote sensing devices and edge systems. Network compression techniques have therefore been proposed to reduce model size and computational cost while maintaining predictive performance. In this study, we conduct a systematic evaluation of neural network compression methods for a remote sensing application, namely hyperspectral land cover classification. Specifically, we examine three widely used compression strategies for convolutional neural networks: pruning, quantization, and knowledge distillation. Experiments are conducted on two benchmark hyperspectral datasets, considering classification accuracy, memory consumption, and inference efficiency. Our results demonstrate that compressed models can significantly reduce model size and computational cost while maintaining competitive classification performance. These findings provide insights into the trade-offs between compression ratio, efficiency, and accuracy, and highlight the potential of compression techniques for enabling efficient deep learning deployment in remote sensing applications.
Figures & tables
Figure 1: Random selection vs. spatially disjoint samples on the IP and UP dataset, considering the same number of samples per class
Figure 2: The implementation details of spectral model (CNN1D) , spatial model (CNN2D), and spatial-spectral model (CNN3D)
Figure 3: A typical three-stage network pruning pipeline
Figure 4: Three types of fine-tuning schemes: (a) One-shot pruning: prune and retrain the model only once (b) Iterative pruning: prune layer by layer, and retrain the model before pruning the next layer (c) Multi-pass pruning: prune and retrain the whole network, then repeat this process until satisfied
Approach
Paper
Network
Size Reduction
Datasets
Application
[ 93 ]
MobileNet, ResNet
80%
OPTIMAL-31
Scene Classification
[ 108 ]
2D-CNN
97%
Indian Pines, Salinas, Xiongan
Hyperspectral Classification
[ 57 ]
VGG, ResNet
70%
AID, NWPU45, PatternNet, WHU19
Scene Classification
[ 92 ]
2D-CNN
80%
Bijie
Landslides Recognition
Pruning
[ 32 ]
AlexNet, VGG
-
UC Merced, NWPU-RESISC45
Scene Classification
[ 67 ]
3D-CNN
-
Indian Pines, Pavia University
Hyperspectral Classification
Table 1: Existing work of neural network compression in remote sensing applications
Quantization Modes
Data Requirements
Inference Latency
Inference Accuracy Loss
Dynamic Quantization
No Data
Fast
Smallest
Static Quantization
Unlabeled data
Fastest
Small
Quantization Aware Training
Labeled data
Fastest
Smallest
Table 2: Different quantization modes
Figure 5: Different distillations modes. Blue: networks are learned before distillation; Yellow: networks are learned during distillation
INDIAN PINES
PAVIA UNIVERSITY
# trainable parameters
Disjoint
Random
Disjoint
Random
RF
-
66.1
79.4
68.5
88.8
MLR
-
78.5
83.5
74.6
90.5
SVM
-
69.9
81.0
79.8
95.8
MLP
31,047
82.4
88.9
82.5
92.5
LSTM
102,416
80.7
88.4
78.1
96.1
Table 3: Top-1 accuracy for baseline models (c: number of channels after PCA)
Conv1
Conv2
fc1
fc2
Total
Memory (MB)
MLP
-
-
-
-
31,047
0.13
CNN1D
-
-
-
-
72,416
0.29
CNN2D
50,050
125,100
250,100
909
426,866
1.71
Prune (90%)
15,015
11,280
22,530
496
49,321
0.60
Prune (95%)
10,010
5,020
10,020
336
25,386
0.31
Prune (98%)
5,005
1,260
2,510
176
8,951
0.12
Table 4: Number of parameters in each layer and memory consumption for original and pruned models
Conv1
Conv2
fc1
fc2
# of filters
# of neurons
CNN2D
50
100
2,500
100
Prune (90%)
15
30
750
30
Prune (95%)
10
20
500
20
Prune (98%)
5
10
250
10
Table 5: Number of remaining filters in Conv layers and neurons in FC layers after pruning
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (Pruning ratio: 90%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.5
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
82.8
97.6
99.2
99.9
77.7
99.7
99.6
99.9
Table 6: Top-1 and Top-5 accuracy of model using pruning methods (90% reduction)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (Pruning ratio: 95%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.4
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
82.1
97.1
99.3
100
74.1
99.6
99.0
100
Table 7: Top-1 and Top-5 accuracy of model using pruning methods (95% reduction)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (Pruning ratio: 98%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.4
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
78.2
96.4
98.9
100
77.2
99.9
98.1
100
Table 8: Top-1 and Top-5 accuracy of model using pruning methods (98% reduction)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Pruning Ratio
Fine-tuning Strategy
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
I
84.6
98.1
99.3
99.9
82.0
99.6
99.4
100
II
86.1
97.5
99.6
99.9
81.7
99.7
99.5
100
90%
III
81.5
97.9
99.2
99.9
81.3
98.9
98.7
99.9
I
86.1
98.4
99.4
99.9
83.0
99.3
99.3
100
Table 9: Different fine-tuning strategy using L1-norm pruning method (Strategy I: prune once and retrain; Strategy II: prune and retrain iteratively; Strategy III: Multi-pass scheme)
INDIAN PINES
PAVIA UNIVERSITY
Memory (MB)
Inference Latency (ms/sample)
Disjoint
Random
Disjoint
Random
MLP
0.13
0.34
82.4
88.9
82.5
92.5
CNN1D
0.29
0.62
82.5
89.4
82.3
93.5
CNN2D
1.71
3.28
86.3
99.4
83.2
99.3
Dynamic Quantization
0.96
2.58
86.5
99.4
83.2
99.6
Static Quantization
0.44
0.70
86.7
99.4
83.3
99.6
Table 10: Neural network performance using different quantization modes (converted from float32 into int8)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (student network: 90%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.5
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
82.8
97.6
99.2
99.9
77.7
99.7
99.6
99.9
Table 11: Top-1 and Top-5 accuracy of student model using knowledge distillation methods (90% reduction)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (student network: 95%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.5
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
82.1
97.1
99.3
100
74.1
99.6
99.0
100
Table 12: Top-1 and Top-5 accuracy of student model using knowledge distillation methods (95% reduction)
INDIAN PINES
PAVIA UNIVERSITY
Disjoint
Random
Disjoint
Random
Methods (student network: 98%)
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
Top-1
Top-5
MLP
82.4
98.6
88.9
99.7
82.5
99.5
92.5
99.9
CNN-1D
82.5
97.9
89.4
99.5
82.3
99.7
93.5
99.9
Baselines
CNN-2D
86.3
98.7
99.5
99.9
83.2
99.9
99.3
100
Scratch
Pruned CNN2D
78.2
96.4
98.9
100
77.2
99.9
98.1
100
Table 13: Top-1 and Top-5 accuracy of student model using knowledge distillation methods (98% reduction)