Location and recognition of flashlight projections for visual interfaces

We consider the location and recognition of flashlight projections given the image sequence supplied by a fixed camera monitoring a physical surface. A quotient method extracts a description of the flashlight projection that is independent of the reflectance of the illuminated surface. The information recovered is used to recognise individual flashlights and trigger audiovisual events in response to users' actions. A demonstration application, an interactive poster, is described and directions for future work identified.