Multi-user interface and interactions on direct-touch horizontal surfaces: collaborative tabletop research at MERL

While "displays" have the connotation of affording visual output, "surfaces" invite the users to interact. What happens then when the surfaces are also displays, when a direct input interface space and output visual space are superimposed onto the same touch interactive surfaces? In the past three years at MERL, we have systematically examined, studied and evaluated, holistically, user interface and interaction techniques on one particular type of direct touch computational surfaces - multitouch multiuser tabletops. We have created and prototyped a set of novel interface systems ranging from a photo story sharing table called PDH (personal digital historian) to the DiamondSpin tabletop tool kit, and UbiTable, to interaction concepts including CoRDs, Modal Spaces, Glimpse multilevel input model, ExpressiveTouch bimanual gestures and bifocal tabletop display interactions. We have also obtained preliminary findings on nonspeech audio feedback on multi-user interactive tabletops, and some of the effects of the size of tables and size of groups on different aspects of multiuser collaboration. Our future research investigates interaction and visualization across table centric interactive spaces with multiple surfaces of tabletops and walls in a new project called DiamondSpace.