# Holcombe:MotionTracking

Alex Holcombe
• Ryo Nakayama

## Interceptive timing

• Bassin anticipation timer and 'Modified Bassin Anticipation Timer' for timing swinging bat etc.

## Motion tracking

• tablet (Wacom A2), holding a stylus in their dominant hand. The tablet recorded the two-dimensional position of the stylus at a frequency of 200 Hz. (Avoiding moving obstacles M. Pilar Aivar Æ Eli Brenner Æ Jeroen B. J. Smeets )
• The monitor was viewed through a mirror that was placed half way between a serial digitizing tablet (Calcomp DrawingBoard III 34240) and the monitor in order for the virtual image to be perceived on top of the tablet. Binocular information of the distance of the stimulus plane, thus, did not conflict with the proprioceptive distance cue of the unseen hand. The position of the pen on the tablet was recorded at a frame rate of 200 Hz. The individual position data time series were digitally low-pass filtered with a Butterworth filter (cutoff frequency of 5 Hz) (primo y Joan)

### 3D motion tracking

• the Motion Analysis HiRes system from Motion Analysis Corporation. it was done in 1998, so it is out of date and the systems have better accuracy and resolution now.
• Vicon another top system
• Polhemus webpage Liberty system starts at $7995.00. This includes a standard source and one standard sensor. Additional sensors are USD$600.00 each. The Fastrak starts at $6350.00 and additional sensors are$500.00 each. THe Patriot system starts at $2500.00 and an additional sensor is$600.00. This is maximum for the patriot. It only allows for 2 sensor configuration.
• Flock Of Birds
• The ninth international symposium on three dimensional analysis , I couldn’t see any accuracy tests but lots on the technical applications. One comparison from 1998 is at http://www.arielnet.com/topics/comparison/

### Elbow tracking

• length to fulcrum 47 cm
• good viewing dist 60 cm when arms straight out
• voltage should be passed through potentiometer, something like -5 volts in one wire, +5 for other. Green wire is ground I think
• to provide time-marker of stim start, should use analog mini-RCA jack for inputting to A/D converter and PC that records joint angle. Or could use digital input they don't use