Interacting with digital tabletops.

A digital tabletop is sufficiently different from the standard desktop computer in that it invites researchers to challenge traditional perspectives on human–computer interaction, such as rethinking the use of a computer as a solitary act, the kinds of activities people want to do with computers, the types of social interactions that can be part of digital interactions, and how the interplay between digital and social needs can be supported. These new perspectives come in part from the historical use of tables to support group activities and in part from the growing interest in supporting collaborative activities digitally. Researchers in both academia and industry have stepped enthusiastically up to the plate. As a result, digital tabletop interaction has become an active and varied research area. Although digital tabletops have been around for nearly 20 years, a serious obstacle to their widespread research is that most sites had to invent and build their own digital table, often at considerable cost and effort. Thus tables varied—often widely—in basic technologies , physical appearance and hardware capabilities, size, display, and input. These often led to idiosyncrat-ic software capabilities, such as display and input-specific interfaces and interaction techniques. It also meant that each site could not easily leverage hardware and software developed by others, requiring constant rein-vention of the wheel. Fortunately, this is changing due to the availability of digital tabletop platforms. Mitsubishi Electric Research Laboratories, for example, developed the Diamond-Touch multiuser input surface. 1 Rather than keep it in-house, they donated this technology, along with a basic tabletop software toolkit called the DiamondSpin, to selected university research laboratories across the globe. 2 Similarly, technologies intended for touch-sensitive vertical displays—such as those produced by Smart Technologies and Mimeo—can be purchased and repurposed as a table simply by laying them flat. This readily available technology encouraged new research on digital tabletops, where groups could concentrate on table interaction instead of low-level hardware and software design. This not only led to a relatively recent renewal of interest in this interaction environment, but the formation of a community, that is, the organization of the first IEEE workshop (held in Adelaide, Australia, in January 2006) devoted specifically to tabletop research. Even as we write this introduction, new table-top hardware and software platforms are being show-cased at the Emerging Technologies exhibit at the ACM Siggraph 2006 conference. Of course, these existing technologies provide particular hardware and software combinations, which not only …