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109:. The luminance component describes the brightness of each part of the picture, while the chrominance component describes the colour tone. When displayed on a black-and-white monitor, the luminance signal produces a normal black-and-white image, while the chrominance signal manifests as a fine pattern of dots of varying size and intensity overlaid over the black-and-white picture. A related phenomenon is
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engineer, noticed that when playing back a copy of a black-and-white telerecording through colour video equipment, spurious colour was generated by the presence of chroma dots in the picture. He theorised that it might be possible to use the chroma dots to reconstruct the original colour signal, and
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television or monitor. They are commonly found on black-and-white recordings of television programmes originally made in colour. Chroma dots were once regarded as undesirable picture noise, but recent advances in computer technology have allowed them to be used to reconstruct the original colour
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In the early days of colour television, it was common practice for broadcasters to produce black-and-white film copies of colour programmes for sale and transmission in territories lacking colour broadcast facilities or employing different colour television systems. During the
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episode "Room at the Bottom" using information from the chroma dot patterning. The process has since been used to restore other programmes including the pilot episode of
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In 2008, it was announced that members of the working group had successfully managed to restore the
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Reconstructed Colour picture (reconstructed using software written by
Richard Russell)
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Example of the chroma dot reconstruction (please view images at 100%)
253:"BBC - Press Office - Dad's Army episode to be seen in colour"
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in 2007 set up a working group to carry out further research.
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signal from black-and-white recordings, providing a means to
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are visual artifacts caused by displaying an unfiltered
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Analogue colour video signals comprise two components:
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202:"Recapturing colour from black and white film"
79:Quadrant calculation for Colour reconstruction
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39:Example of the chroma dot reconstruction:
278:"BBC Two - Are You Being Served?, Pilot"
67:Black and white picture with chroma dots
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26:analogue colour video signal on a
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178:, episode 1; and episodes 2-6 of
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228:"Color Recovery Working Group"
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175:Invasion of the Dinosaurs
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157:Are You Being Served?
124:telerecording process
169:Planet of the Daleks
309:Display technology
208:. 11 December 2008
130:Use in restoration
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107:chrominance
20:Chroma dots
188:References
163:Doctor Who
151:Dad's Army
97:Background
257:bbc.co.uk
111:dot crawl
103:luminance
33:re-colour
303:Category
287:29 March
262:29 March
237:29 March
212:29 March
117:History
289:2015
264:2015
239:2015
214:2015
105:and
282:BBC
166:. (
142:BBC
24:PAL
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