Abstract: An interactive presentation system uses a presentation computer, a computer-controlled image projector and a projection screen, in which control of the presentation computer is accomplished by using a wireless optical pointer that projects an encoded control cursor onto the projection screen. The projected screen images are monitored by a video camera, and the control cursor is scanned, detected and decoded for emulating various keyboard commands and/or pointing device (mouse, touch pad, track ball) position-dependent cursor operations. The control cursor is reliably detected and its coordinate location is accurately determined on the basis of one or more primary image attributes, for example image intensity and image repetition rate, both of which are independent of monitoring angles and pointing device projection angles, and one or more secondary image attributes, for example image size, color and pattern.

Abstract: A touch-sensitive matrix switch assembly includes a pair of transparent insulating substrates having conductive row strips and column strips. The conductive row strips and column strips are separated by longitudinal extending channels, and an insulating spacer strip is deposited in each row channel and in each column channel. The substrates are mounted together with the row conductors extending transversely with respect to the column conductors. An air gap between the row conductors and column conductors is provided by the engagement of the row spacer strips against the column spacer strips. The space strips are formed by very small diameter transparent glass or polymer particles which are mixed with a transparent polymer adhesive in a volatile solvent. The glass or polymer particle/adhesive mixture is sprayed into the channels through a mask to produce a transparent, non-conductive glass or polymer deposit which is enlarged slightly out of the channel, thereby defining a spacer strip.