A study on the effects of lightning and marker color variation to marker detection and tracking accuracy in gait analysis system

This work is a part of the project to develop a multicamera 3-D gait analysis system based on passive markers. The system consists of two modules, i.e. the camera synchronization and calibration module and the marker detection and tracking module. The work presented in this paper concerns with the automatic detection of 2-D marker coordinates from the video recording produced by one camera. 2-D coordinates as a result from this module could be transformed into 3-D gait coordinates when combined with another 2-D coordinates detected from different camera, by using the calibration module. Videography is one of common methods for gait analysis, in which we use one or more camera for passive marker detection and tracking. These passive markers are reflective markers that reflect light from light source around them to camera and result as proportional electric current from camera to computer. Detection and tracking module developed in this work is based on videography method and has three specifications that are it has ability to detects passive marker in normal condition of light, it designed for 3D application, and it has ability to detect several colors of markers for solving the problem rise from false marker detection in condition where marker displacement on each frame transition bigger than distance between markers on patient.