MH-Net: Multiheaded 3D Hand Pose Estimation Network With 3D Anchorsets and Improved Multiscale Vision Transformer

Accurate 3D hand pose estimation is a challenging computer vision problem primarily because of self-occlusion and viewpoint variations. Existing methods address viewpoint variations by applying data-centric transformations, such as data alignments or generating multiple views, which are prone to data sensitivity, error propagation, and prohibitive computational requirements. We improve the estimation accuracy by mitigating the impact of self-occlusion and viewpoint variations from the network side and propose MH-Net, a novel multiheaded network for accurate 3D hand pose estimation from a depth image. MH-Net comprises three key components. First, a multiscale feature extraction backbone based on an improved multiscale vision transformer (MViTv2) is proposed to extract shift-invariant global features. Second, a 3D anchorset generator is proposed to generate three disjoint sets of 3D anchors that serve two purposes: formulating hand pose estimation as an anchor-to-joint offset estimation and defining three unique viewpoints from a single depth image. Third, three identical regression heads are proposed to regress 3D joint positions based on unique viewpoints defined by their respective anchorsets. Extensive ablation studies have been conducted to investigate the impact of anchorsets, regression heads, and feature extraction backbones. Experiments on three public datasets, ICVL, MSRA, and NYU, show significant improvements over the state-of-the-art.