Applying the peephole metaphor in a mixed-reality room

This article presents the generalized peephole metaphor, a model of interaction for ubiquitous computing and instrumented environments. The metaphor provides a way of organizing and structuring ubiquitous input and output facilities in instrumented environments consisting of several distributed but coordinated sensors and displays. Its main idea is to look at the environment as one large display and sensor continuum, in which peepholes provide localized and user-specific windows between the physical environment and a virtual information layer. The metaphor nicely matches models of human perception, for example the fact that humans make use of external representation in their environments and access information by guiding their attention to specific locations. The article presents a specific mixed-reality room and shows how a number of input and output activities can be described in terms of the peephole metaphor. It discusses how the metaphor can cope with scalability and access control and how it supports a family of interaction styles and presentation methods in instrumented environments. It analyzes the technological requirements for implementing the peephole metaphor and show that it works well with the limited hardware already available, such as projector-camera units, wall-mounted displays, and portable screens. © 2006 IEEE.