Multipoint digital automatic white balance for a video system
First Claim
1. An apparatus comprising:
- means for producing digitized red, green and blue channel data;
means for sampling the red, green and blue channel data at a plurality of illumination levels;
means for addressing locations within red, green and blue look-up-tables based on the values of the sampled red, green and blue channel data, wherein at least one of the red, green and blue look-up-tables contains base line data; and
means for retrieving base line data from the locations addressed in the look-up-table containing base line data and for storing the retrieved base line data in the locations addressed in the look-up-tables that do not contain base line data.
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Abstract
A multipoint digital automatic white balance system is provided that automatically compensates for changes in illumination conditions. Three color channels are balanced by measuring the relative output of the red to green channels and the blue to green channels at many different illumination levels. Base line measurements obtained in the green channel are used to create calibrated green channel data that is stored in a green channel LUT, which in turn is used to create corresponding red and blue channel data that is stored in red and blue LUTs. In operation, digitized red, green and blue input signals are applied to the red, green and blue LUTs to generate white balance corrected red, green and blue output signals.
38 Citations
7 Claims
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1. An apparatus comprising:
- means for producing digitized red, green and blue channel data;
means for sampling the red, green and blue channel data at a plurality of illumination levels;
means for addressing locations within red, green and blue look-up-tables based on the values of the sampled red, green and blue channel data, wherein at least one of the red, green and blue look-up-tables contains base line data; and
means for retrieving base line data from the locations addressed in the look-up-table containing base line data and for storing the retrieved base line data in the locations addressed in the look-up-tables that do not contain base line data. - View Dependent Claims (2, 3)
- means for producing digitized red, green and blue channel data;
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4. A method of providing multipoint white balance correction comprising the steps of:
- sampling red, green and blue channel data at a plurality of illumination levels;
addressing locations within red, green and blue look-up-tables based on the values of the sampled red, green and blue channel data, wherein at least one of the red, green and blue look-up-tables contains base line data;
retrieving the base line data from the location addressed in the look-up-table containing the base line data; and
storing the retrieved base line data in the locations addressed in the look-up-tables that do not contain base line data. - View Dependent Claims (5, 6, 7)
- sampling red, green and blue channel data at a plurality of illumination levels;
Specification