Using Pressure Patterns to Detect Natural Motions for
Traversing Virtual Environments, 07-9178

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Principal Investigators
Warren C. Couvillion Jr.
Roger R. Lopez
Jian Ling

Inclusive Dates: 01/01/00 - 12/31/00

Background - Although some inexpensive methods of navigating virtual environments are in use, they are unnatural, such as flying in the direction that the userís finger is pointing. Attempts to use natural motions to navigate virtual environments have included moving a surface beneath the user or attaching a large number of sensors to the user.

Approach - The research teamís goal was to develop an inexpensive, nonintrusive method to detect motions similar to those in the real world, such as walking in place, and to use this information to navigate in a virtual environment. A pressure-sensitive mat (patent pending) detected the patterns made as the user walked. Pressure-sensitive resistors were arranged hexagonally to reduce directional bias on a thick plastic sheet. The resistors were connected to a computer through an analog-to-digital card.

The team defined a set of gestures for walking forward, backward, right and left, and used several visualizations to determine if the pressure patterns were distinct and repeatable. Data were then recorded from several subjects to determine an algorithm for detecting the step patterns. Finally, the team wrote a real-time application to read the pressure mat and detect the userís gesture. These data were used to move the viewpoint in rendering a three-dimensional environment in the userís head-mounted display.

Accomplishments - The team successfully detected whether a user was standing; walking forward or backward; or moving right or left. This information was then utilized to allow users to traverse virtual environments successfully. They were able to pick out landmarks in the virtual environment, and move to them by walking in place using motions similar to those used in the real world.

The unique prototype system allows users to navigate in virtual environments using real-world motions, such as walking, to improve the realism of the virtual reality application.
SwRI staff wrote software for a suite of visualizations to illustrate the pressure patterns made by walking. Here the pressures are shown as positive prints.

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