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US 2018/0007333 A1Published application
Per pixel color correction filtering
AssigneeApple Inc.
InventorsSuk Hwan Lim, D. Amnon Silverstein, David R. Pope
Life of this patent
Estimating the term…
Abstract
Embodiments relate to color correction circuit operations performed by an image signal processor. The color correction circuit computes optimal color correction matrix on a per-pixel basis and adjusts it based on relative noise standard deviations of the color channels to steer the matrix.
Claims23
An image signal processor comprising:
- a per-pixel color correction matrix circuit configured to compute a modified color correction matrix for each pixel in the image data, and generate first color values by at least applying the modified color correction matrix to the image data,
- wherein applying the modified color correction to a smoothed version of the image data results in same color values as the smoothed version of the image data applied with a standard color matrix, and
- wherein an expected noise variance value of the first color values is lower than an expected noise variance value in color values obtained by applying the standard color matrix to the image data.
A method of performing color correction on image data with a plurality of color channels, comprising:
- compute a modified color correction matrix for each pixel in the image data;
- and
- generate first color values by at least applying the modified color correction matrix to the image data, wherein applying the modified color correction to a smoothed version of the image data results in same color values as the smoothed version of the image data applied with a standard color matrix, and wherein an expected noise variance value of the first color values is lower than an expected noise variance value in color values obtained by applying the standard color matrix to the image data.
An electronic device comprising:
- an image sensor;
- and
- an image signal processor coupled to the image sensor and configured to receive image data from the image sensor, the image signal processor comprising:
- a per-pixel color correction matrix circuit configured to compute a modified color correction matrix for each pixel in the image data, and generate first color values by at least applying the modified color correction matrix to the image data, wherein applying the modified color correction to a smoothed version of the image data results in same color values as the smoothed version of the image data applied with a standard color matrix, and wherein an expected noise variance value of the first color values is lower than an expected noise variance value in color values obtained by applying the standard color matrix to the image data.
1 more element
Dependencies are inferred from the claim text.