Sistema de captura de movimiento para un laboratorio de análisis de la marcha

Abstract

Gait analysis uses a variety of strategies to capture and evaluate the motion patterns of body segments, including motion capture systems with passive or active markers, inertial systems with sensors attached to the body, and visual information processing techniques without the need for markers. Each of these approaches has advantages and disadvantages in terms of accuracy, portability, installation complexity, cost, and computational requirements, so the choice of the appropriate method will depend on the specific objectives of the analysis and the characteristics of the research environment. This project describes the implementation of an optical motion capture system based on passive reflective markers, for the Rehabilitation Engineering laboratory of the Universidad Politécnica Salesiana Sede Girón, for which a system composed of eight infrared cameras provided by the manufacturer OptitrackTM was used. This system was implemented in an area of 25 m2 , with the cameras configured and calibrated to avoid occlusion and ensure accuracy in capturing different body segments during movements. For this purpose, a calibration scheme of the cameras has been implemented to obtain the information recording area defined as a capture volume, thus achieving the three-dimensional recording of the trajectories of the markers of the subject under analysis. For the visualization and processing of the information, a biomechanical model is implemented, which allows to simulate the captured movements and to establish clinical measurements of the body movements. All this based on open source libraries. Finally, kinematic studies were performed, obtaining the Euler angles of both the lower and posterior part of the subject. The results obtained from the angular measurements for gait analysis were contrasted against a conventional evaluation scheme using KINOVEA software, showing a correlation coefficient for both the knee and shoulder joints. Being a useful system in the areas of biomechanics and rehabilitation engineering as it allows to evaluate and monitor gait in healthy patients or patients with pathologies, it also constitutes a scenario for the development of new techniques for gait analysis in general.