A system for identifying a program stream being displayed at a receiver location comprises means at a central station for measuring the relative luminance of a plurality of predetermined areas in each frame and recording that data with their times of occurrence for each of a plurality of program streams as reference data, and means at a receiver location to measure the relative luminance of the same areas but at a repetition rate less than that at the central station for a given time after a channel change and thereafter at an even lower repetition rate and storing the measurements at the receiver location with times defining corresponding broadcast times, and means for transmitting the stored data to the central station for correlating the measured and reference data using the recorded times to access the corresponding measured values of the recorded and reference data.
A system identifies which of first and second signal sources is supplying a program signal to a monitored receiver. The first and second signal sources and the monitored receiver are located in a household. The system extracts a reference program signature representative of an output of the monitored receiver and first and second source program signatures representative of an output of the first and second signal sources. The system identifies which of the first and second signal sources is a source of the program signal in response to the reference program signature and the first and second source program signatures.
An audience rating system for digital television and radio, using identification codes in control streams of time-multiplexed digital transmissions. When a television set or radio, that is being monitored pursuant to the system, is turned on and tuned into a channel, and each time that the channel is changed, an identification code for each audio, video or auxiliary digital stream of the channel is extracted from the control stream, and recorded along with the time. In the first preferred embodiment, the multiplexed digital transmission is received separately by the television set or radio (or an attached IRD) and a meter connected to it. In the second preferred embodiment, the meter does not receive the multiplexed digital transmission separately, but has access to elementary streams extracted from the transmission by an IRD, and extracts identification codes for the channels being received from their elementary streams.
An audience rating system for digital television and radio, using identification codes in control streams of time-multiplexed digital transmissions. When a television set or radio, that is being monitored pursuant to the system, is turned on and tuned into a channel, and each time that the channel is changed, an identification code for each audio, video or auxiliary digital stream of the channel is extracted from the control stream, and recorded along with the time. The time is also recorded when the television set or radio is turned off. This data makes it possible to determine what stations, channels, and programs members of the audience being monitored are watching or listening to at any particular time. In the first preferred embodiment, the multiplexed digital transmission is received separately by the television set or radio (or an attached IRD) and a meter connected to it. The meter compares digital streams of the channel being received by the television set or radio with digital streams of each of the channels in the multiplexed digital transmission, until it finds a match. In the second preferred embodiment, the meter does not receive the multiplexed digital transmission separately, but has access to elementary streams extracted from the transmission by an IRD, and extracts identification codes for the channels being received from their elementary streams. The elementary stream may be accessed through an auxiliary connector in a digital decoder, through an access control card connector, or through soldering electrical connections to internal points in the IRD.
Large amounts of multimedia data are transmitted over information networks in the form of a digital stream, analog video, or text captioning. Often, repetitions such as paid advertisements, theme music at the commencement of a TV broadcast, and common jingles and slogans occur in these streams. Detection of repetitions in a transmitted signal such as streaming audio or video is described, and includes extracting a plurality of samples from the information stream and accumulating the samples into segments comprising an interval of the transmitted signal. A vector indicative of the samples in each of the segments is generated, and each of the vectors in the segments is correlated to generate a covariance matrix, or signature, corresponding to the segment. Each of the covariance matrices are aggregated into a sequence of covariance matrices and compared to other covariance matrices to generate a distance matrix. The distance matrix includes a distance value, indicative of the similarity between the distance matrices, as a result of the comparing of each matrix. The distance matrix is then traversed to determine similar sequences of covariance matrices.
A real-time distortion analysis system (20) utilizes a baseline preparation processor (38) and a remote comparison processor (50) to determine (72, 78) a plurality of color and central moments for baseline and broadcast video streams respectively. The baseline stream is taken from a broadcast signal sent from a broadcast station (26), and the broadcast video stream is taken from a viewer signal sent from a remote receiving station (28, 30, 32) to viewers (34). The remote comparison processor (50) compares (82), on a frame by frame basis, the baseline and broadcast moments and determines a cumulative absolute difference which reflects differences between the two video streams. To conduct a frame by frame analysis of the two video streams, the system (20) temporally aligns the video streams. Alternatively, the system (20) uses a moment database (88) to compare the moments at a time subsequent to broadcast.
