Virginia Polytechnic Institute and State University

ESM 4714 Fall 2000

Christopher W. Thornton


"Visualizing the Discrepancy between Physical and Virtual Measurement of the Six Degrees of Freedom in the CAVE"




Project Background


Tracking system accuracy in the CAVE is a continuing issue in the visualization community. Two questions of interest to this type of project is as follows.

  1. Can environmental characteristics introduce error into tracking system data?
  2. Do inherent errors in the tracking systems exist?

For example, the Ascension Flock of Birds is an electromagnetic traking system. Can this system be influenced by ambient EMFs and the structural metal in the area. The Intersense IS-900 is an ultrasonic tracking system. Can this system be influenced by ambient ultasonic "noise".


This project is the continuation of one that I began in the Spring 2000 semester. The following are the original target goals for this project.

- Record the physical measurements of x,y,z,h,p,r in the CAVE.

x = x Cartesian position

y = y Cartesian position

z = z Cartesian position

h = heading (yaw)

p = pitch

r = roll

- Record the virtual measurements of x,y,z,h,p,r in the CAVE (position according to the Intersense IS-900 tracking system).

- Model the discrepancies of physical versus virtual x,y,z,h,p,r in the CAVE.


However, due to the inavailability of the CAVE this semester, the following are the topics of this project.

- Describe the CAVE measurement procedure for the Intersense IS-900 (will work with any tracing system)

- Model of the CAVE measurement points

- Example of tracker data visualization (virtual tracker position)