White balance adjustment device and color identification device
AssigneeEastman Kodak Company
InventorTakanori Miki
Life of this patent
Estimating the term…
Abstract
The present invention is directed to improving the accuracy of white balance adjustment. An image input from an image capture device 10 is divided into blocks, and white balance gains are calculated from a representative value of each block. Prior to calculation of the representative value of each block, a color range determining circuit 13 determines whether each pixel included in each block belongs to a light source color range, or belongs to an apparent object color range. A representative value of that block is calculated from remaining pixels other than pixels determined to belong to the apparent object color range. Thus, by preventing the representative value from being affected by an object color, the accuracy of white balance gains is improved.
Claims16
A white balance adjustment device for adjusting white balance of an input image, the white balance adjustment device comprising:
- dividing means for dividing an input image into a plurality of blocks;
- determining means for determining, from a color difference of each pixel included in each of the blocks, whether or not each pixel is of an object color;
- representative value calculating means for calculating a representative value for each of the blocks, from remaining pixels that are obtained by excluding, from pixels included in each of the blocks, pixels determined to be a pixel of an object color;
- and
- gain calculating means for calculating white balance gains from the representative values calculated for all the blocks.
A white balance adjustment device for adjusting white balance of an input image, the white balance adjustment device comprising:
- dividing means for dividing an input image into a plurality of clusters on the basis of chromaticities of pixels of the input image;
- representative value calculating means for calculating a representative value for each of the clusters;
- determining means for determining, from the representative value, whether or not each cluster is of an object color;
- and
- gain-calculating means for calculating white balance gains from representative values of remaining clusters that are obtained by excluding, from all the clusters, clusters determined to be a cluster of an object color.
A white balance adjustment device for adjusting white balance using a representative value of each block obtained by dividing an input image into a plurality of blocks, the white balance adjustment device comprising:
- selecting means for selecting, from all pixels included in each of the blocks, pixels representing a light source color;
- and
- calculating means for calculating the representative value from only the selected pixels.
A white balance adjustment device for adjusting white balance from a representative value of each cluster obtained by dividing an input image into a plurality of clusters, each cluster being formed of a group of pixels having identical chromaticity, the white balance adjustment device comprising:
- selecting means for selecting, from all the clusters, clusters representing a light source color;
- and
- adjustment means for adjusting the white balance from only representative values of the selected clusters.
A color identification device for identifying whether or not a pixel or cluster included in an input image represents a light source color, the color identification device comprising:
- color difference calculating means for calculating a color difference of the pixel or cluster;
- memory means for storing, as a light source color range, a color difference range corresponding to an object that has an achromatic color under a plurality of light sources, and for storing, as object color ranges, color difference ranges corresponding to particular color objects, both the light source color range and the object color ranges being defined on a color difference plane;
- and
- processing means for determining whether or not the color difference of the pixel or cluster belongs to the light source color range or the object color ranges stored by the memory means, to thereby identify whether or not the pixel or cluster represents a light source color.
Dependencies are inferred from the claim text.