In the context of rehabilitation medicine, human movement analysis is best suited to an integration of observational techniques and measurements of physiological signals. For this purpose, the SYBAR system was developed. SYBAR is based on a combination of an intelligent data acquisition controller, a video digitizer and SYBAR software, to integrate the synchronized data streams and allow user-domain specific visualization.

The Syntech IDAC (Intelligent Data Acquisition Controller) combines a 16- channel data acquisition system with independent and fully software- programmable input amplifiers in a single instrument. For each of the 16 channels, the DC offset, gain, band pass and notch (50/60 Hz) filter and sampling rate (1-50 kHz) can be programmed individually. Each channel is provided with its own 16 bit D/A converter, the outputs of which are digitally multiplexed for transfer to the PC via the USB port. Data communication via the USB port also programs all gains and digital filter settings per channel. The software takes care of real-time on-screen presentation of all signals before and during recording, and monitors the effects of the amplifier settings. Stored data can be manually or automatically post-processed and exported. In SYBAR, the IDAC is configured to record bipolar surface EMG via 8 channels, while six other channels connect to a force plate measuring ground reaction force. The trigger from a synchronization generator is also recorded.

Videos are digitized using either commercially available digitalization or the SYBAR software. In the first case, a synchronization pulse is inserted visually into the video stream. Digitizing by means of the SYBAR software provides the option of reading the VITC (vertical interval time code) from the video stream itself. In this way, synchronization with physiological signals can be achieved either automatically or manually (using the visually inserted synchro-pulse).

After importing files from IDAC, SYBAR can customize the visualization of the various signals. This includes video overlay ('enhanced reality') of the ground reaction force vector. Thus, meaningful representations of the recorded signals are obtained (i.e. relevant to the user group). The user interface of this domain- specific application is kept straightforward, and can be tailored to groups of users.

Paper presented at Measuring Behavior 2002 , 4^th International Conference on Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, The Netherlands

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