A computer simulation study and component evaluation for a quaternion filter for sourceless tracking of human limb segment motion
Contributors: Naval Postgraduate School (U.S.) 
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 1997
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 92
Subjects: VIRTUAL REALITY; HUMAN FACTORS ENGINEERING; MAN COMPUTER INTERFACE
Description: Current methods of tracking the human body within virtual environments (VE) are hampered by problems due to      interference which occurs from using artificially generated source signals. In recent years, the miniaturization of      self-contained inertial tracking systems has made them a viable alternative. They are impervious to external      interference but require filtering in order to give accurate orientation data. Filters for this purpose using Euler angles      are common, but are limited by their inability to track through the vertical axis. A filter based on quaternions would      not have this limitation. This thesis presents an implementation of a quaternion filter in Lisp. The filter was tested      with a computer simulated inertial tracker. Also presented is a quantitative and qualitative assessment of an existing      inertial tracker, Angularis, which uses a filter based on Euler angles. This effort resulted in an improved filter based      on quaternions which allows objects to be tracked through the vertical axis making it a more desirable option for      body tracking applications. The evaluation of the Angularis inertial tracker yielded generally good results when      tested on a tilt-table at various rates of motion through 45 degrees of rotation. Specifically, orientation errors      measured were typically less than one degree for smooth motion. However, when moved rapidly through large      orientation angles, it was found that the nonlinear characteristic of the proprietary filter resulted in large steady state      errors.
Notes: Thesis advisors, Robert B. McGhee, John S. Falby.

AD-A331 813.

Thesis (M.S. in Computer Science) Naval Postgraduate School, March 1997.

Includes bibliographical references (p. 87-89)

dk/dk cc:9116 11/14/97.