Table 1 Comparison of methods.
Feature/method | Standard 3D U-Net | Attention U-Net | Multi-scale pyramid networks | Proposed method |
|---|---|---|---|---|
Multi-scale input | Single-scale | Single-scale | Serial or fused input | Parallel multi-scale input paths |
Attention mechanism | None | Channel/spatial attention | Typically integrated into encoder | Spatial attention embedded in skip connections |
Core design objective | General segmentation | Enhance response to key regions | Enhance multi-scale perception | Preserve karst topological connectivity |
Boundary optimization strategy | Dice/cross-entropy | Same as left | Same as left | Dice + boundary-aware loss (gradient L1) |
Geological adaptability | Limited | Limited | Moderate | High (targeting karst scale and connectivity) |
