A spatial–frequency dual–domain network for remote sensing water body segmentation
摘要
Accurate extraction of water bodies from high-resolution remote sensing imagery underpins flood monitoring, water resource management, and ecological assessment. Two structural challenges persist in this task: maintaining long-range structural continuity of river and canal networks, which local convolutions fail to preserve across large spatial extents; and fine-grained boundary discrimination at water–land interfaces, where spectral similarity between water and surrounding backgrounds causes spatial-domain features to over-smooth shorelines and narrow channels. We propose a spatial–frequency dual-domain feature enhancement network for water body extraction that addresses both challenges by integrating an axial gated depthwise convolution module at deep encoder features and a frequency-domain boundary enhancement module at mid-resolution features. The axial gated module captures long-range spatial context at low-resolution encoder features, while the frequency-domain module performs band-selective spectral gain modulation at mid-level features to preserve fine boundary detail. Both modules are integrated into a ConvNeXt-Tiny encoder–decoder architecture and evaluated on three public benchmarks. Our method achieves Dice scores of 0.894 on DeepGlobe, 0.878 on Gaofen (+4.6 pp over DiffRoad, the strongest Gaofen baseline), and 0.897 on LoveDA (water/non-water setting, +3.0 pp). It ranks first in Dice on Gaofen and LoveDA, where complex urban waterways and shadow interference pose severe challenges, and remains competitive with the strongest transformer-based models on DeepGlobe. Bootstrap significance tests confirm that the observed gains over all convolutional baselines are statistically significant (