Motion Analysis
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The VICON 612 (Oxford Metrics Ltd., Oxford, UK) is a precision measurement instrument designed to locate and track retroreflective markers moving in a calibrated measurement space (about 8 feet long and 3 feet wide in our lab). It can also synchronize voltage recordings from a wide range of transducers, such as EMGs or force plates. Although the system is designed primarily for use in biomechanics research and clinical medicine, movements of any type can be measured and analyzed.
Marker trajectories are measured by six, 120Hz video cameras. The measurement space is illuminated by infra-red strobe lights mounted on each camera, whose output is invisible to the human eye. Illumination, video data collection, and analog to digital conversion of transducer input (force plate data and EMG data), is synchronized and controlled by the VICON 612 Datastation, which is in turn controlled by a Pentium-based PC running the Windows 2K operating system. The results of photogrammeretric measurement and analog data collection are stored in a published file format (C3D). These data are then processed using the biomechanical model contained in the VICON Clinical Manager (VCM) software. Within this program, the gait cycle is defined by identifying heel-strike and toe-off. Graphs are then produced showing angles at the pelvis, hip, knee and ankle. Plots of joint moment, power, and ground reaction force are also produced. Click here for an AVI Demo of Vicon 612 (612 KB) Click here for an AVI Demo of Vicon Polygon Bones walking (821 KB) Oxford Metric's web site may be found at: |