## 6 Discussion  
The feature-matching method based on entropy rate superpixel seeds and adaptive morphological reconstruction (AMR) proposed in this paper has shown significant advantages in experiments. Compared with traditional superpixel segmentation methods, its segmentation accuracy has been improved, and the phenomenon of over-segmentation has been reduced. This improvement is mainly due to the adaptive filtering capability of the AMR method for invalid seed points. By combining the LOG (Laplacian of Gaussian) operator to extract contour features, AMR can effectively distinguish meaningful areas in the surface morphology (such as ablation marks, scratches) from noise. For example, when there is complex light reflection on the contact group surface, traditional methods are prone to over-segmentation due to noise interference, while AMR reduces the impact of uneven lighting on image segmentation through multi-scale Gaussian functions and morphological reconstruction operations. In addition, the entropy rate-based balance function ensures the consistency of the size of the segmented areas, thereby further enhancing the robustness of feature extraction. The AMR method exhibits stronger adaptability when dealing with non-uniform surfaces (such as local ablation areas). In the reconstruction of ablation areas, the AMR method successfully preserves the details of the ablation edges, while traditional methods result in detail loss due to over-reliance on fixed threshold segmentation. However, the computational complexity of AMR is relatively high, and efficiency issues may arise when processing large-scale point cloud data. Future research can further enhance its practical application value by optimizing iterative algorithms or introducing parallel computing.  
The three-dimensional fractal contact model based on the W-M function proposed in this paper has shown improvements in predicting contact area and estimating contact resistance over existing models, thanks to an in-depth understanding of the multi-scale features and deformation mechanisms of micro-asperities. Compared to traditional statistical models, such as the GW model, the fractal model avoids the impact of measurement instrument accuracy on surface morphology characterization by introducing scale parameters, such as fractal dimension and characteristic scale. Furthermore, the model incorporates the elastic, elastoplastic, and fully plastic deformation mechanisms of micro-asperities, enabling a more realistic simulation of the non-linear mechanical processes during actual contact.  
Experimental data indicate that at a fractal dimension of 2.5, the contact area exhibits an approximate 3/2 power law relationship with the load, which is consistent with the predictions of the classical Hertz theory under elastic contact conditions. However, at higher loads, the model predicts a slower increase in contact area, reflecting the impact of elastoplastic deformation on the contact process. Additionally, the introduction of the substrate curvature (as shown in Equation (16)) significantly enhances the model's applicability to actual contact groups, such as arc-shaped contacts. For instance, as the substrate curvature radius increases, the contact area decreases under the same load, but the contact stability improves. This conclusion aligns with the engineering practice of \"increasing contact pressure to reduce arc erosion\" in the design of railway relay contacts.