Interactive graphics transmission system employing an adaptive stylus for reduced bandwidth

Abstract

An interactive graphics transmission system for use, illustratively, in video teleconferencing is described which advantageously reduces the amount of transmission bandwidth and user effort required to transmit changing graphical information. This is accomplished by first transmitting a full image of the graphic followed only by the changes which a conferee makes to that graphic. Those changes are determined by sensing the tilt of a light pen and the location of its tip, which is closest to the graphic, as a conferee manipulates the pen to change the graphic. The tilt of the pen primarily determines the mode in which the light pen is used. The mode information, in conjunction with the location of the pen's tip, is used to generate an instruction which specifies the way in which the graphic is to be changed, e.g., whether information is to be added to, deleted from or emphasized in a graphic. In addition, the location of the pen's tip specifies the address of that portion of the graphic that is to be changed. By transmitting just the instruction and address information while the user simultaneously manipulates the light pen to change a graphic, transmission bandwidth and user effort are both advantageously minimized.

Dependencies are inferred from the claim text.