Patent US 4,646,145

Television viewer reaction determining systems generate distinct signals indicative of different viewer reactions to television programs. These systems generate a further signal identifying any of the mentioned distinct signals as indicative of a viewer reaction to an unspecified person appearing in any video program. The mentioned distinct and further signals are gathered, and the unspecified person is identified from such gathered signals. The gathering of the mentioned signals is preferably effected in real time within a tolerance corresponding to an average rate of change of persons appearing in the video programs.