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US 2007/0177032 A1Published application
Automatic color calibration of an image sensor
AssigneeNethra Imaging Inc.
InventorPing Wong
Life of this patent
Estimating the term…
Abstract
In one embodiment of the invention, a method is provided. The method, comprises (a) determining a white balance correction parameter for a white balance correction processing block for an image sensor, and including the white balance correction parameter in the white balance correction processing block; (b) determining a gamma correction parameter for a gamma correction processing block for the image sensor, and including the gamma correction parameter in the gamma correction processing block; and (c) determining a color correction parameter for a color correction processing block for the image sensor, and including the color correction parameter in the color correction processing block.
Claims22
A method, comprising:
- (a) determining a white balance correction parameter for a white balance correction processing block for an image sensor, and including the white balance correction parameter in the white balance correction processing block;
- (b) determining a gamma correction parameter for a gamma correction processing block for the image sensor, and including the gamma correction parameter in the gamma correction processing block;
- and
- (c) determining a color correction parameter for a color correction processing block for the image sensor, and including the color correction parameter in the color correction processing block.
1 more element
A method, comprising:
- (a) disabling a gamma correction function, a gain correction function, an offset correction function, and a color correction function for a sensor;
- (b) capturing a first image of a color test chart with the sensor, wherein a pixel value corresponding to each color patch of the color test chart is known;
- (c) determining a first measured pixel value for each color patch in the first image;
- (d) determining gamma correction parameters for the sensor based on differences between each first measured pixel value for a color patch and the known pixel value for that color patch;
- (e) enabling the gamma correction function for the sensor using the gamma correction parameters determined in step (d);
- (f) with the gamma correction function enabled, capturing a second image of the color test chart with the sensor, and determining a second measured pixel value for each color patch in the second image;
- (g) determining gain and offset parameters for the gain and offset corrections, respectively based on differences between each second measured pixel value for a color patch and the known pixel value for that color patch;
- (h) enabling the gain correction function and the offset correction function for the sensor, wherein for the gain correction function the channel gain parameters determined in step (g) are used, and for the offset correction function the offset parameters determined in step (g) are used;
- (i) capturing a third image of the color test chart with the sensor and with the gamma correction function, the gain correction function, and the offset correction function enabled;
- (j) determining a third measured pixel value for each color patch in the third image;
- and
- (k) determining color correction parameters for the color correction function based on differences between each third measured pixel value for a color patch and the known pixel value for that color patch.
9 more elements
The method, wherein the sensor is of a particular sensor design, and steps (a) to (k) are performed for each sensor design.
A computer-readable medium having stored thereon, a sequence of instructions which when executed by a processor, cause the processor to perform a method comprising:
- (a) disabling a gamma correction function, a gain correction function, an offset correction function, and a color correction function for a sensor;
- (b) capturing a first image of a color test chart with the sensor, wherein a pixel value corresponding to each color patch of the color test chart is known;
- (c) determining a first measured pixel value for each color patch in the first image;
- (d) determining gamma correction parameters for the sensor based on differences between each first measured pixel value for a color patch and the known pixel value for that color patch;
- (e) enabling the gamma correction function for the sensor using the gamma correction parameters determined in step (d);
- (f) with the gamma correction function enabled, capturing a second image of the color test chart with the sensor, and determining a second measured pixel value for each color patch in the second image;
- (g) determining gain and offset parameters for the gain and offset corrections, respectively based on differences between each second measured pixel value for a color patch and the known pixel value for that color patch;
- (h) enabling the gain correction function and the offset correction function for the sensor, wherein for the gain correction function the channel gain parameters determined in step (g) are used, and for the offset correction function the offset parameters determined in step (g) are used;
- (i) capturing a third image of the color test chart with the sensor and with the gamma correction function, the gain correction function, and the offset correction function enabled;
- (j) determining a third measured pixel value for each color patch in the third image;
- and
- (k) determining color correction parameters for the color correction function based on differences between each third measured pixel value for a color patch and the known pixel value for that color patch.
9 more elements
A system, comprising:
- a processor;
- and
- a memory coupled to the processor, the memory storing instructions which when executed by the processor, cause the processor to perform a method comprising:
- (a) disabling a gamma correction function, a gain correction function, an offset correction function, and a color correction function for a sensor;
- (b) capturing a first image of a color test chart with the sensor, wherein a pixel value corresponding to each color patch of the color test chart is known;
- (c) determining a first measured pixel value for each color patch in the first image;
- (d) determining gamma correction parameters for the sensor based on differences between each first measured pixel value for a color patch and the known pixel value for that color patch;
- (e) enabling the gamma correction function for the sensor using the gamma correction parameters determined in step (d);
- (f) with the gamma correction function enabled, capturing a second image of the color test chart with the sensor, and determining a second measured pixel value for each color patch in the second image;
- (g) determining gain and offset parameters for the gain and offset corrections, respectively based on differences between each second measured pixel value for a color patch and the known pixel value for that color patch;
- (h) enabling the gain correction function and the offset correction function for the sensor, wherein for the gain correction function the channel gain parameters determined in step (g) are used, and for the offset correction function the offset parameters determined step (g) are used;
- (i) capturing a third image of the color test chart with the sensor and with the gamma correction function, the gain correction function, and the offset correction function enabled;
- (j) determining a third measured pixel value for each color patch in the third image;
- and
- (k) determining color correction parameters for the color correction function based on differences between each third measured pixel value for a color patch and the known pixel value for that color patch.
12 more elements
Dependencies are inferred from the claim text.