PostureHMR: Posture Transformation for 3D Human Mesh Recovery

Human Mesh Recovery (HMR) aims to estimate the 3D human body from 2D images, which is a challenging task due to inherent ambiguities in translating 2D observations to 3D space. A novel approach called PostureHMR is pro-posed to leverage a multi-step diffusion-style process, which converts this task into a posture transformation from an SMPL T-pose mesh to the target mesh. To inject the learning process of posture transformation with the physical structure of the human body model, a kinematics-based forward process is proposed to interpolate the intermediate state with pose and shape decomposition. Moreover, a mesh-to-posture (M2P) decoder is designed, by combining the in-put of 3D and 2D mesh constraints estimated from the im-age to model the posture changes in the reverse process. It mitigates the difficulties of posture change learning directly from RGB pixels. To overcome the limitation of pixel-level misalignment of modeling results with the input image, a new trimap-based rendering loss is designed to highlight the areas with poor recognition. Experiments conducted on three widely used datasets demonstrate that the proposed approach outperforms the state-of-the-art methods.