CD$^2$: Fine-grained 3D Mesh Reconstruction with Twice Chamfer Distance

Monocular 3D reconstruction is to reconstruct the shape of object and its other detailed information from a single RGB image. In 3D reconstruction, polygon mesh is the most prevalent expression form obtained from deep learning models, with detailed surface information and low computational cost. However, some state-of-the-art works fail to generate well-structured meshes, these meshes have two severe problems which we call Vertices Clustering and Illegal Twist. By delving into the mesh deformation procedure, we pinpoint the inadequate usage of Chamfer Distance(CD) metric in deep learning model. In this paper, we initially demonstrate the problems resulting from CD with visual examples and quantitative analyses. To solve these problems, we propose a fine-grained reconstruction method CD$^2$ with Chamfer distance adopted twice to perform a plausible and adaptive deformation. Extensive experiments on two 3D datasets and the comparison of our newly proposed mesh quality metrics demonstrate that our CD$^2$ outperforms others by generating better-structured meshes.