Use of video shadow for small group interaction awareness on a large interactive display surface

Abstract

This paper reports work done as part of the Large Interactive Display Surface (LIDS) project at the University of Waikato. One application of the LIDS equipment is distributed meeting support. In this context large display surfaces are used as shared workspaces by people at collaborating sites. A meeting with start with a shared presentation document, typically and agenda document with summary and detail on agenda items as required. During the meeting, annotations with be made on the shared document, and new pages will be added with notes and drawings. To prevent access collisions and generally mediate use of the shared space, mechanisms to provide awareness of actions of people at other sites are required. In our system a web camera is used to capture a low-resolution image of the person/people near the board on each side. Rather than transmit the image directly we computed a shadow/silhouette. The shadow is displayed behind other screen content. This provides awareness of position and impending write actions and allows intentional pointing to locations of the screen. It also has the advantage of being transmitted with low bandwidth, being relatively insensitive to low frame rates, and minimizing visual interference with substantive data being displayed on the screen.