title: Measuring gait using a ground laser range sensor.
abstract: This paper describes a measurement system designed to register the displacement of the legs using a two-dimensional laser range sensor with a scanning plane parallel to the ground and extract gait parameters. In the proposed methodology, the position of the legs is estimated by fitting two circles with the laser points that define their contour and the gait parameters are extracted applying a step-line model to the estimated displacement of the legs to reduce uncertainty in the determination of the stand and swing phase of the gait. Results obtained in a range up to 8 m shows that the systematic error in the location of one static leg is lower than 10 mm with and standard deviation lower than 8 mm; this deviation increases to 11 mm in the case of a moving leg. The proposed measurement system has been applied to estimate the gait parameters of six volunteers in a preliminary walking experiment.
authors.affiliation: Department of Computer Science and Industrial Engineering, University of Lleida, Jaume II, 69, 25001 Lleida, Spain; E-Mails:  tpalleja@diei.udl.cat  (T.P.);  mteixido@diei.udl.cat  (M.T.);  mtresanchez@diei.udl.cat  (M.T.).
authors.forename: Tomàs
authors.initials: T
authors.lastname: Pallejà
authors.forename: Mercè
authors.initials: M
authors.lastname: Teixidó
authors.forename: Marcel
authors.initials: M
authors.lastname: Tresanchez
authors.forename: Jordi
authors.initials: J
authors.lastname: Palacín