British Broadcasting Corporation

Ian Childs

Richard Storey

Charles P Sandbank

Field-rate upconversion of television signals

Bandwidth compression for television signals

Video signals (Y,U,V) from a telecine machine are accompanied by a blemish signal (D) (obtained for example by infra-red scanning of a color film) indicating the presence of scratches, dirt etc. This controls a switch (22) to substitute information from another part of the film (e.g. the previous frame, from a frame store 33). To prevent substitution with information also containing blemishes, the blemish signal in respect of the substitute information is made available (flag store 36) to suppress the substitution and switch to an alternative source such as a interpolator (31). The use of a movement detector, (not shown) to suppress substitution from another frame when motion occurs, is also described. The circuitry can be adapted for use in conjunction with a videotape dropout detector.

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Sutton, United Kingdom

Ian Childs