Figure 1.

Establishing point correspondence between the ground truth (dashed curve) and the reconstructed mesh (solid curve) with (a) the Chamfer and (b) the LP & Chamfer approach. We focus on the part of the meshes and ground truth landmarks (red crosses $a^{\prime }$, $c^{\prime }$ and $e^{\prime }$) on the nose. The estimated nose tip with the Chamfer method, ${\widehat{c}}^{\prime }$, is far from the true nose tip $c^{\prime }$. Also, the point $b$ is approximately in the middle of the nose root $a$ and tip $c$, but its counterpart ${\widehat{b}}^{\prime }$ estimated with the Chamfer method is closer to $a^{\prime }$ than $c^{\prime }$ (a similar observation holds for $d$ and ${\widehat{d}}^{\prime }$). LP non-rigidly aligns the meshes by “pulling” the nose tip $c$ towards $c^{\prime }$ with a force of $u_c$ and dragging all the points on the mesh. Thus, LP & Chamfer finds better correspondences ${\widehat{b}}^{\prime }$ and ${\widehat{d}}^{\prime }$ as well as ${\widehat{c}}^{\prime }$.