Fig. 8: Overall framework of CartiSurface.

Starting from a 3D knee MRI, femoral and tibial subchondral surfaces are extracted and uniformly sampled to provide geometric anchors. These samples are fed into an implicit SDF network, implemented as an MLP with skip connections, to reconstruct a continuous cartilage volume. A geometry-aware loss enforces anatomically meaningful constraints, including consistent inter-surface spacing, local parallelism, and smooth curvature. The resulting cartilage thickness is estimated across the joint and visualized as surface heatmaps, providing smooth, clinically interpretable maps robust to MRI resolution and noise.