Multi-Variate Gaussian-Based Inverse Kinematics

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Bibliographic Details
Title: Multi-Variate Gaussian-Based Inverse Kinematics
Authors: Huang, J., Wang, Q., Fratarcangeli, Marco, 1974, Yan, K., Pelachaud, C.
Source: Computer Graphics Forum. 36(8):418-428
Subject Terms: Animation, Guassian process, Jacobian, Clustering, Inverse kinematics, I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism
Description: Inverse kinematics (IK) equations are usually solved through approximated linearizations or heuristics. These methods lead to character animations that are unnatural looking or unstable because they do not consider both the motion coherence and limits of human joints. In this paper, we present a method based on the formulation of multi-variate Gaussian distribution models (MGDMs), which precisely specify the soft joint constraints of a kinematic skeleton. Each distribution model is described by a covariance matrix and a mean vector representing both the joint limits and the coherence of motion of different limbs. The MGDMs are automatically learned from the motion capture data in a fast and unsupervised process. When the character is animated or posed, a Gaussian process synthesizes a new MGDM for each different vector of target positions, and the corresponding objective function is solved with Jacobian-based IK. This makes our method practical to use and easy to insert into pre-existing animation pipelines. Compared with previous works, our method is more stable and more precise, while also satisfying the anatomical constraints of human limbs. Our method leads to natural and realistic results without sacrificing real-time performance.
File Description: electronic
Access URL: https://research.chalmers.se/publication/248859
http://publications.lib.chalmers.se/records/fulltext/248859/local_248859.pdf
Database: SwePub
Description
Abstract:Inverse kinematics (IK) equations are usually solved through approximated linearizations or heuristics. These methods lead to character animations that are unnatural looking or unstable because they do not consider both the motion coherence and limits of human joints. In this paper, we present a method based on the formulation of multi-variate Gaussian distribution models (MGDMs), which precisely specify the soft joint constraints of a kinematic skeleton. Each distribution model is described by a covariance matrix and a mean vector representing both the joint limits and the coherence of motion of different limbs. The MGDMs are automatically learned from the motion capture data in a fast and unsupervised process. When the character is animated or posed, a Gaussian process synthesizes a new MGDM for each different vector of target positions, and the corresponding objective function is solved with Jacobian-based IK. This makes our method practical to use and easy to insert into pre-existing animation pipelines. Compared with previous works, our method is more stable and more precise, while also satisfying the anatomical constraints of human limbs. Our method leads to natural and realistic results without sacrificing real-time performance.
ISSN:14678659
01677055
DOI:10.1111/cgf.13089