Automatic monitoring of the quality of cable television pictures

A system which automatically detects and recognizes impaired cable television pictures is proposed. The automatic detection and recognition of pictures impaired by (1) intermodulation beats and (2) snow noise are discussed. It is shown that the two-dimensional Fourier spectrum of any picture impaired by an intermodulation beat contains four pulses with a distinguishing characteristic which renders the identification of the presence of a beat feasible. For snow noise an improved method which estimates the signal-to-noise ratio of any picture is proposed. From the above it is concluded that the automatic monitoring of the quality of the cable picture may be done in a nonintrusive fashion and without the use of a test signal