US 4,942,466 AGranted

Bandwidth compression for television signals

AssigneeBritish Broadcasting Corporation

InventorsCharles P. Sandbank, Ian Childs, Richard Storey

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Abstract

A video signal received from a source (10) is bandwidth-compressed by filters (12, 14, 16), filter (14) being a temporal filter and filter (16) being a spatial filter. Selection of the filter to be used is dependent upon picture content. The transmitter reconstitutes in interpolators (44, 46) the signal which would be regenerated at the receiver, determines which filter gives the best results, and transmits an indication of which filter has been used in a digital signal associated with the analogue video signal. Preferably a determination of motion vectors associated with the signal is made and the digital signal indicates which of the determined motion vectors is applicable to different areas of the picture. By transmitting the control signal digitally with the analogue video signal the receiver circuitry is greatly simplified while its reliability is improved.

Claims17

Dependent claims

A system for transmission of analogue video signals comprising, at a transmitter:

an analogue video signal source;
sampling means for sampling the analogue video signal generated by the source;
bandwidth compression means for compressing the bandwidth of the video signal generated by the source selectively by two or more different methods in response to a control signal, and including sub-sampling means for sub-sampling the sampled analogue video signal generated by the source;
means for converting the sub-sampled, bandwidth compressed video signal into analogue form;
means for transmitting the bandwidth-compressed video signal in analogue form;
control signal generating means responsive to the picture content of the video signal generated by the source to generate the control signal for successive picture areas to command the bandwidth compressing means to select a required one of the bandwidth compression methods for successive picture areas;
and at a receiver;
means for receiving the transmitted bandwidth-compressed video signal;
means for reconstituting a signal for display from the bandwidth-reduced transmitted video signal selectively by two or more different methods in dependence upon picture content;
and means for displaying the reconstituted signal;
further including:
means at the transmitter for transmitting in association with the analogue video signal a digital signal comprising the said control signal;
and
means at the receiver responsive to the transmitted digital signal to extract the control signal and command the reconstituting means to select the required one of the reconstituting methods for successive picture areas to reconstitute the signal for display.

11 more elements

Dependencies are inferred from the claim text.