Organizations: State Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao 266100, China · Department of Electrical and Computer Engineering, Mississippi State University, Starkville, MS 39762 USA
Remote sensing image semantic segmentation (RSISS) has attracted significant attention due to the growing demand for fine-grained land cover information. The Segment Anything Model (SAM), proposed as a foundation vision model, offers strong segmentation performance and generalization capabilities for RSISS tasks. However, existing SAM-based approaches face two limitations: (1) Insufficient adaptation of SAM's features to the diverse characteristics of land cover types. (2) Semantic ambiguity at object boundaries, which hinders accurate delineation. To address these limitations, we propose Frequency and Edge-guided SAM (FE-SAM), a scalable and efficient framework for RSISS. Specifically, we introduce a Frequency-Modulated Adapter (FMA) that adaptively decomposes and modulates frequency-domain features based on the input data. It selectively enhances informative high- and low-frequency components corresponding to different land cover types. Furthermore, to improve SAM's ability to capture fine-grained details, we design EGRefiner, which integrates multi-scale edge-enhanced information extracted from the input image. Extensive experiments on three benchmark datasets demonstrate that FE-SAM outperforms state-of-the-art methods. The source codes are available at: https://github.com/oucailab/FE-SAM.
Figures & tables
Fig. 1: Framework of our Frequency and Edge-guided Segment Anything Model ( FE-SAM ) for remote sensing image semantic segmentation. It reuses the pre-trained weights of SAM with two novel modules: Frequency-Modulated Adapter (FMA) and Edge-Guided Refiner (EGRefiner).
Fig. 2: Framework of our Frequency and Edge-guided Segment Anything Model ( FE-SAM ) for remote sensing image semantic segmentation. It reuses the pre-trained weights of SAM with two novel modules: Frequency-Modulated Adapter (FMA) and Edge-Guided Refiner (EGRefiner).
Fig. 3: Cross-dataset spectral analysis. Top rows: representative patches and their 2D log-magnitude spectra from SA-1B and three remote sensing datasets. Bottom: averaged radial PSD curves.
Fig. 4: Illustration of the Edge-Guided Refiner (EGRefiner).
Class
Pixels( ×106 )
Proportion(%)
Vaihingen
Imp. surf.
121.5
29.2
Building
113.6
27.3
Low veg.
79.1
19.0
Tree
80.7
19.4
Car
5.0
1.2
Clutter
16.2
3.9
TABLE I: Pixel-level class distribution on three datasets
Fig. 5: Statistical significance analysis of mIoU on the ISPRS Vaihingen and Potsdam datasets.
Method
Type
Vaihingen
Potsdam
LoveDA
FCN8s
CNN- based
78.25
81.03
48.02
U-Net
80.96
83.96
50.46
DeepLabv3+
81.78
84.02
51.45
MA-Net
82.76
84.91
51.64
A2-FPN
82.40
85.16
52.20
UNetFormer
Transformer- based
82.86
85.24
52.44
TABLE II: Semantic segmentation results (measured by mIoU) of various methods on three benchmark datasets. The bold and underline denote the best and second results.
Method
Type
Backbone
Per-class F1-score
mIoU(%)
m-F1(%)
OA(%)
Imp.surf.
Building
Low veg.
Tree
Car
FCN8s
CNN- based
VGG-16
95.22
91.89
81.76
88.52
79.68
78.25
87.41
88.96
U-Net
ResNet-18
96.03
94.51
82.58
88.73
83.76
80.96
89.12
89.94
DeepLabv3+
ResNet-18
96.38
95.13
82.88
88.86
84.84
81.78
89.62
90.50
MA-Net
ResNet-18
96.39
95.17
83.86
89.51
86.33
82.76
90.25
90.69
A2-FPN
ResNet-18
96.31
95.04
83.01
89.08
86.67
82.40
90.02
90.52
TABLE III: Quantitative comparisons with the state-of-the-art methods on the ISPRS Vaihingen dataset. The bold and underline denote the best and second results.
Fig. 6: Additional qualitative results on the ISPRS Vaihingen dataset. From top to bottom, each row showcases a different challenging scene. Our model, FE-SAM (last column), consistently produces segmentation masks that are more detailed and accurate than those from competing methods.
Method
Type
Backbone
Per-class F1-score
mIoU(%)
m-F1(%)
OA(%)
Imp. surf.
Building
Low veg.
Tree
Car
FCN8s
CNN- based
VGG-16
90.62
92.55
85.02
85.95
92.48
81.03
89.32
88.00
U-Net
ResNet-18
92.31
94.56
85.82
87.37
95.01
83.96
91.01
89.60
DeepLabv3+
ResNet-18
92.78
95.07
86.10
87.41
94.86
84.02
91.24
89.70
MA-Net
ResNet-18
92.86
95.30
86.47
87.77
95.45
84.91
91.57
90.41
A2-FPN
ResNet-18
93.08
95.79
86.53
88.00
94.84
85.16
91.65
90.44
TABLE IV: Quantitative comparisons with the state-of-the-art methods on the ISPRS Potsdam dataset. The bold and underline denote the best and second results.
Fig. 7: Additional qualitative results on the ISPRS Potsdam dataset. Our model, FE-SAM (last column), consistently generates more accurate and complete segmentation masks compared to other state-of-the-art methods, especially in areas with complex object layouts.
Method
Type
Backbone
Per-class IoU
mIoU(%)
Background
Building
Road
Water
Barren
Forest
Agriculture
FCN8s
CNN- based
VGG-16
54.46
63.95
56.88
62.66
11.83
32.30
47.03
48.02
U-Net
ResNet-18
54.16
58.56
57.19
57.93
27.31
41.54
56.53
50.46
DeepLabv3+
ResNet-18
54.39
60.15
58.09
63.30
26.52
41.94
55.38
51.45
MA-Net
ResNet-18
54.76
60.94
57.10
62.18
34.82
37.26
54.42
51.64
A2-FPN
ResNet-18
55.64
62.00
58.42
65.56
28.08
42.19
53.54
52.20
TABLE V: Quantitative comparisons with the state-of-the-art methods on the LoveDA dataset. The bold and underline denote the best and second results.
Fig. 8: Additional qualitative results on the LoveDA dataset. The selected scenes showcase diverse urban and rural landscapes. Our model, FE-SAM (last column), consistently provides more complete and semantically accurate segmentation masks than competing methods.
Method
Backbone
mIoU (%)
B-IoU
B-IoU
( d=8 )
( d=16 )
U-Net[42]
ResNet-18
80.96
73.12
75.48
DeepLabv3+[43]
ResNet-18
81.78
74.56
76.82
UNetFormer[46]
ResNet-18
82.86
76.28
78.53
SAM[8]
ViT-B
83.04
75.82
77.96
SAM-Adapter[50]
SAM-B
83.35
77.14
79.21
TABLE VI: Quantitative comparison of boundary segmentation quality on the ISPRS Vaihingen dataset. B-IoU ( d=8 ) and B-IoU ( d=16 ) measure the accuracy within 8 and 16 pixels from the boundary
Method
Total Params(M)
FLOPs(M)
FPS
SAM [8]
86.94
103.17
15.6
SAM-Adapter [50]
90.78
109.61
14.1
RSPrompter [18]
93.45
113.66
11.8
Semantic-SAM [52]
101.12
115.83
10.2
FE-SAM (Ours)
94.52
114.11
12.4
TABLE VII: Model complexity comparison of SAM-based methods.
Fig. 9: Comparison of mIoU, total parameters, and inference speed among SAM-based methods.
FMA
EGRefiner
Vaihingen
Potsdam
LoveDA
83.04
85.94
52.54
✓
84.06
86.50
54.13
✓
83.57
86.25
53.64
✓
✓
85.24
86.73
55.66
TABLE VIII: Ablation studies on different modules of FE-SAM.
Fig. 10: Visual comparisons of feature representations before and after the FMA module. From left to right: original remote sensing images, feature heatmaps before FMA, and feature heatmaps after FMA.
Method
Trainable Params (M)
Vaihingen
Potsdam
LoveDA
Full tuning
83.02
83.04
85.94
52.54
Adapter
7.83
83.12
86.09
53.14
LoRA
7.09
83.20
86.15
53.07
FMA (Ours)
7.56
84.06
86.50
54.13
TABLE IX: Comparison of different parameter-efficient fine-tuning strategies. Performance is measured in mIoU(%).
FMA Configuration
Vaihingen
Potsdam
LoveDA
Baseline (w/o FMA)
83.57
86.25
53.64
Fixed LPF/HPF (Generic)
84.12
86.41
54.02
Fixed LPF/HPF (Learned)
84.45
86.50
54.31
FMA (Ours)
85.24
86.73
55.66
TABLE X: Ablation on the necessity of FMA’s adaptive partitioning, evaluated across all three benchmark datasets. Performance is measured in mIoU(%).
Fig. 11: Visual validation of FMA’s adaptive frequency partitioning on the ISPRS Vaihingen dataset.
Fig. 12: Visual validation of FMA’s adaptive frequency partitioning on the ISPRS Potsdam dataset.
Configuration
Vaihingen
Potsdam
LoveDA
Single-Scale DConv 3x3
84.72
86.55
54.71
Single-Scale DConv 5x5
84.85
86.60
55.06
Single-Scale DConv 7x7
84.81
86.58
54.89
Multi-Scale DConv (Ours)
85.24
86.73
55.66
TABLE XI: Ablation study on the multi-scale architecture of EGRefiner on three benchmark datasets (mIoU%).
Fig. 13: Qualitative comparison visualizing the efficacy of the Edge-Guided Refiner (EGRefiner) for boundary refinement on challenging scenes from the ISPRS Vaihingen dataset.
EGRefiner Configuration
Vaihingen
Potsdam
LoveDA
w/o Element-wise Subtraction
84.65
86.48
55.03
w/o Channel-wise Concat
84.81
86.55
55.21
w/o Fs Feature Fusion
79.32
81.05
49.58
EGRefiner (Full, Ours)
85.24
86.73
55.66
TABLE XII: Ablation study on the architectural components of the EGRefiner, evaluated across all three benchmark datasets.