Ball joints for Marker-less human Motion Capture

verfasst von: Gerard Pons Pons-Moll, Bodo Rosenhahn
Abstract: This work presents an approach for the modeling and numerical optimization of ball joints within a Marker-less Motion Capture (MoCap) framework. In skeleton based approaches, kinematic chains are commonly used to model 1 DoF revolute joints. A 3 DoF joint (e.g. a shoulder or hip) is consequently modeled by concatenating three consecutive 1 DoF revolute joints. Obviously such a representation is not optimal and singularities can occur. Therefore, we propose to model 3 DoF joints with spherical joints or ball joints using the representation of a twist and its exponential mapping (known from 1 DoF revolute joints). The exact modeling and numerical optimization of ball joints requires additionally the adjoint transform and the logarithm of the exponential mapping. Experiments with simulated and real data demonstrate that ball joints can better represent arbitrary rotations than the concatenation of 3 revolute joints. Moreover, we demonstrate that the 3 revolute joints representation is very similar to the Euler angles representation and has the same limitations in terms of singularities.
Organisationseinheit(en): Institut für Informationsverarbeitung
Typ: Aufsatz in Konferenzband
Publikationsdatum: 2009
Publikationsstatus: Veröffentlicht
Peer-reviewed: Ja
ASJC Scopus Sachgebiete: Angewandte Informatik, Maschinelles Sehen und Mustererkennung
Elektronische Version(en): https://doi.org/10.1109/WACV.2009.5403056 (Zugang: Unbekannt)

BibTeX

@inproceedings{69feb45b82264cddba47462a478da941,
title = "Ball joints for Marker-less human Motion Capture",
abstract = "This work presents an approach for the modeling and numerical optimization of ball joints within a Marker-less Motion Capture (MoCap) framework. In skeleton based approaches, kinematic chains are commonly used to model 1 DoF revolute joints. A 3 DoF joint (e.g. a shoulder or hip) is consequently modeled by concatenating three consecutive 1 DoF revolute joints. Obviously such a representation is not optimal and singularities can occur. Therefore, we propose to model 3 DoF joints with spherical joints or ball joints using the representation of a twist and its exponential mapping (known from 1 DoF revolute joints). The exact modeling and numerical optimization of ball joints requires additionally the adjoint transform and the logarithm of the exponential mapping. Experiments with simulated and real data demonstrate that ball joints can better represent arbitrary rotations than the concatenation of 3 revolute joints. Moreover, we demonstrate that the 3 revolute joints representation is very similar to the Euler angles representation and has the same limitations in terms of singularities.",
author = "Pons-Moll, {Gerard Pons} and Bodo Rosenhahn",
year = "2009",
doi = "10.1109/WACV.2009.5403056",
language = "English",
isbn = "9781424454976",
series = "2009 Workshop on Applications of Computer Vision, WACV 2009",
booktitle = "2009 Workshop on Applications of Computer Vision, WACV 2009",
note = "2009 Workshop on Applications of Computer Vision, WACV 2009 ; Conference date: 07-12-2009 Through 08-12-2009",
}