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. 73. The method recited in claim 72 further including the step of comparing the extracted signature with reference signatures.