title: Spatiotemporal representation of 3D hand trajectory based on beta-elliptic models.
abstract: The aim of this paper was to model the hand trajectory during grasping by an extension in 3D of the 2D written language beta-elliptic model. The interest of this model is that it takes into account both geometric and velocity information. The method relies on the decomposition of the task space trajectories in elementary bricks. The latter is characterized by a velocity profile modelled with beta functions and a geometry modelled with elliptic shapes. A data base of grasping movements has been constructed and the errors of reconstruction were assessed (distance and curvature) considering two variations of the beta-elliptic model ('quarter ellipse' and 'two tangents points' method). The results showed that the method based on two tangent points outperforms the quarter ellipse method with average and maximum relative errors of 2.73% and 8.62%, respectively, and a maximum curvature error of 9.26% for the former. This modelling approach can find interesting application to characterize the improvement due to a rehabilitation or teaching process by a quantitative measurement of hand trajectory parameters.
authors.affiliation: a REGIM: Research Groups on Intelligent Machines , National School of Engineers (ENIS), University of Sfax , BP 1173, 3038 Sfax , Tunisia.
authors.forename: Houcine
authors.initials: H
authors.lastname: Boubaker
authors.forename: Nasser
authors.initials: N
authors.lastname: Rezzoug
authors.forename: Monji
authors.initials: M
authors.lastname: Kherallah
authors.forename: Philippe
authors.initials: P
authors.lastname: Gorce
authors.forename: Adel M
authors.initials: AM
authors.lastname: Alimi
mesh_terms: D000328:Adult; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008962:Models, Theoretical; D009068:Movement; D013997:Time Factors
keywords: beta functions; elliptic shape; hand trajectory; modelling