Learning 3D joint constraints from vision-based motion capture datasets

Learning 3D joint constraints from vision-based motion capture datasets
Pramod Narasimha Murthy, Hammad Tanveer Butt, Sandesh Hiremath, Alireza Khoshhal, Didier Stricker
MVA 2019. IAPR Conference on Machine Vision Applications (MVA-2019) May 27-31 Tokyo Japan Springer 2019 .

Abstract:

Realistic estimation and synthesis of articulated human motion must satisfy anatomical constraints on joint angles. A data-driven approach is used to learn human joint limits from 3D motion capture datasets. We represent joint constraints with a new formulation (s1,s2,τ) using swing-twist representation in exponential maps form. Our parameterization is applied on Human3.6M dataset to create the lookup-map for each joint. These maps enable us to generate ‘synthetic’ datasets in entire joint rotation space of a given joint. A set of neural network discriminators is then trained with synthetic datasets to learn valid/invalid joint rotations. The discriminators achieve accuracy of [94.4−99.4%] for different joints. We validate precision-accuracy trade-off of discriminators and qualitatively evaluate classified poses with an interactive tool. The learned discriminators can be used as ‘priors’ for human pose estimation and motion synthesis.