Sunday, March 20, 2011

Reference 2: Virtual Reality, Input Devices, Wii Balance Board

"Navigation in Virtual Reality with the Wii Balance Board" is a project by Andre Hilsendeger, Stephan Brandauer, Julia Tolksdorf, Christian Frohlich that uses Wii Balance Board to navigate around virtual reality. Below are the details of the project's document.

Navigation in a Virtual Reality should be intuitive and not interfering with other interactions. But many navigation tools, like data gloves or WiiMote controllers, require at least one hand. This means the user is only able to interact single-handed with the environment while navigating through Virtual Reality. To solve this issue, they decided to use the Wii Balance Board as an input device for navigation because the board opens a low-cost and accessible way to gain input via a channel not used before. In addition, the board's output values may be interpreted in several ways, meaning di fferent navigation metaphors may easily be applied to it. Therefore they realized some of those metaphors and tested them in a comparative user study to determine the best and most intuitive locomotion technique for the environment on the Wii Balance Board.

The Wii Balance Board is a controller for Nintendo's Wii video game console which has one pressure sensor at each corner. The sensor data is transmitted via bluetooth and enables the calculation of the direction the user is leaning to. To retrieve the data from the Wii Balance Board, they decided to use an extended version of the WiiUse library2 which supports the Wii Balance Board. One of the questions that arose was how to use the Wii Balance Board to navigate. Since the Board is a at surface they decided to develop a two-dimensional navigation. Out of two possible solutions - imitate walking by steps on the Board or steer by leaning to the desired direction - they chose the second one since we did expect better results in accuracy, ease of use, speed of learning and lower cognitive load. Furthermore imitate walking may require some physical e ffort and thus is not desired for long term usage.

For a simple use of the board's data, they chose to convert the four sensor values to a threedimensional normalized vector, leaning in the same direction as the user: the user-vector. A physical correct calculation of the user-vector was not realized since their goal was to deliver values the user wants to communicate with his action, not those he actually acts out.

The main reasons were problems we experienced in earlier development steps:
  • it was difficult to stand still in the Virtual Environment: the user had to stand in a close-to-exact position above the center of the board.
  • thresholds, as the simplest solution to the first problem, required constant adjustment, and decreased the immersion due to the discontinuous control-mechanism.
The mentioned problems were solved by introducing equations for two angles of the user-
vector based on all four sensor values:






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