72. A method of identifying a television signal received from either a television receiver or a video recorder for determining audience viewing habits comprising the steps of: detecting predetermined operational modes of the audience member's television receiver and the video recorder; detecting the occurence of a first event in one of the operational modes; detecting the occurence of a second event in the signal to be identified; extracting a signature from a single frame of the video signal to be identified after the occurence of the second event; and storing the extracted signature, the time of the signature extraction and the detected operational mode.
72. A method of identifying a television signal received from either a television receiver or a video recorder for determining audience viewing habits comprising the steps of: detecting predetermined operational modes of the audience member's television receiver and the video recorder; detecting the occurence of a first event in one of the operational modes; detecting the occurence of a second event in the signal to be identified; extracting a signature from a single frame of the video signal to be identified after the occurence of the second event; and storing the extracted signature, the time of the signature extraction and the detected operational mode. 78. The method recited in claim 72 wherein said second event is a still picture.