Picture signal contrast control
DCFirst Claim
Patent Images
1. A method of controlling contrast in a first part of a picture, said picture being represented by a picture signal, said picture signal comprising a number of sub signals each holding color information for different areas of the picture, said color information being represented by a first set of basic colors, each of said basic colors having an amplitude, the method comprising:
- increasing (1) contrast by increasing the amplitudes of all basic colors in a selected sub signal representing that part of the picture to be contrast increased,determining (2–
4) if an amplitude of one of said basic colors exceeds a predefined value, andreducing (2–
4) saturation of said color information if an amplitude of one of said basic colors exceeds the predefined value.
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Abstract
The present invention relates to controlling contrast in at least part of a picture. The contrast control is performed by reducing the saturation (2–4) of the picture during contrast increase (1).
42 Citations
14 Claims
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1. A method of controlling contrast in a first part of a picture, said picture being represented by a picture signal, said picture signal comprising a number of sub signals each holding color information for different areas of the picture, said color information being represented by a first set of basic colors, each of said basic colors having an amplitude, the method comprising:
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increasing (1) contrast by increasing the amplitudes of all basic colors in a selected sub signal representing that part of the picture to be contrast increased, determining (2–
4) if an amplitude of one of said basic colors exceeds a predefined value, andreducing (2–
4) saturation of said color information if an amplitude of one of said basic colors exceeds the predefined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14)
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11. A signal processing device (33) for controlling contrast in a first part of a picture, said picture being represented by a picture signal, said picture signal comprising a number of sub signals each holding color information for different areas of the picture, said color information being represented by a first set of basic colors, each basic color having an amplitude, said signal processor comprising:
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means (1) for increasing the contrast by increasing the amplitudes of the basic colors in the sub signal representing that part of the picture to be contrast increased, means (4) for determining if an amplitude of one of said basic colors exceeds a predefined value, and means (4) for reducing saturation of said color information if an amplitude of one of said basic colors exceeds the predefined value.
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Specification