A Scalable Multi-User Laser Input System

Projection technology has made wall-size displays a common component of modern meeting rooms. However, input technologies that comfortably allow multiple people to share and interact with the displayed data have seen relatively little progress. We introduce a system architecture that allows any number of users to interact simultaneously with a large display surface. In this system, each user utilizes a laser pointer as a pen or pointing device. Using computer vision techniques and Kalman filtering, the system determines the beginning, continuation, and end of all currently active pointer strokes, where a stroke is the continuous path of a laser spot on the display surface from the appearance of the spot to its disappearance. The laser spot position, velocity, and acceleration associated with each currently active stroke is available for use by application programs. This system scales well with display size, display resolution, and number of users.