Motion Capture Discussion Group Homepage

Announcements

from Kang: Wiki created, people...I will upload iQ Basics, more Q&A and other stuff after I am done...

Schedule

Topic	Time	Location
Web Tutorial IQ - Manual Editing	Friday, June 17, 2005	X527
Web Tutorial IQ - VST file Editing	Friday, July 15, 2005	X527
Web Tutorial IQ - Labeling Data	Friday, August 12, 2005	X527

To Capture

Michiel doing cartwheels

To Buy

Mo-cap suits ... (current is a large) and maybe sleeve-less (vest)
Hygienic/medical tapes for direct skin attachment
Soft markers for capture when performing moves involving contact
Black duct tape
Velcro tape (black) ... fuzzy side

Q&A

Q: What dynamic calibration is for?
- A: from P21 of Vicon System Manual
  Static calibration calculates the origin or centre of the capture volume and determines the orientation of the 3D Workspace.
  Dynamic calibration involves movement of a calibration wand throughout the whole volume and allows the system to calculate the relative positions and orientations of the cameras. It also linearises the cameras.
Q: What to do if residuals are still too high? What should they be to begin with. what do they mean?
- A: from P23 of Vicon System Manual
  A residual for each camera is a measure of the accuracy of a single camera. They are larger the greater the distance of the camera from the capture volume and are measured in millimeters. It is the root mean square of the distance between two rays; the first being that from the centre of the strobe ring to the centroid of the marker and the second being the reflected ray from the marker to the camera lens.
  Residuals should be less than 0.1% of the distance from the camera to the centre of the capture volume. For example, our cameras are roughly 3~4 meters from the centre of the volume, the residuals should be less than 3~4mm. So we are good with a 1mm mean residual. Consistency between residual values from all cameras is also important.
  Residual values much higher than those given here may indicate a problem. Mathematically it means that the calibration algorithm failed to converge to a meaningful result. Extraneous reflections or flickering light from elsewhere in the capture space, or reflective material from the person performing the calibration and wand waving might be the noise sources. Try checking the live monitors for additional sources of light.
Q: Why we are getting zero wand visibility?
- A: