ELECTRIC FIELD SENSING FOR GRAPHICAL INTERFACES
Joshua Smith*, Tom White, Christopher Dodge, David Allport†,
Joseph Paradiso*, Neil Gershenfeld*
* Physics and Media Group
MIT Media Laboratory
20 Ames St.
Cambridge, MA. 02139
†VSIS Incorporated
Sunnyvale, CA
Abstract
Low frequency electric fields provide a means to build contact and
non-contact user interfaces that are unobtrusive, responsive,
inexpensive, and simple to configure. In this paper, we outline the
theory and implementation of such sensing techniques, contrasting
them with more familiar alternatives. We then present a range of
applications that we have developed for interacting with computer
graphics.
1) Introduction
The earliest bit-mapped graphical computers have progressed to bring real-time
three-dimensional rendering and digital video to the desktop, but the common physical
interface remains unchanged from the first workstations, as we are still using the same
keyboards and mice. The result is that many applications, such as modeling or navigation
in virtual worlds, are often limited not by processing speed but by the users' difficulty in
conveying desired actions to the computer.
The range of alternative controllers that have been tried are notable, not just for their
diversity, but also for their compromising constraints and/or relatively disappointing overall
performance. They can broadly be divided into non-contact approaches and those that
require contact with the user. The most familiar non-contact interface is video, using one or
more cameras to determine the users' actions [1]. The canonical problems with video are
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To be published in the Special Issue on Input Devices, IEEE Computer Graphics and Applications, May 1998
the difficulty in obtaining estimates faster than standard video frame rates, the need for
enormous input bandwidth and computational power to process the images, and the
requirement to constrain the scene background, activity, and illuminat