Automatic white balance using non-uniform averaging

A system comprising:

• an optical element;
• an image sensor coupled to the optical element, the image sensor comprising:
• a pixel array including a plurality of pixels,
• an automatic white balance (AWB) circuit coupled to the pixel array to:
• transform red, green, and blue color data obtained from each pixel into x and y chromaticity values for each pixel;
• determine a distance between a Planckian locus and the x and y chromaticity values for each pixel;
• determine a weight for each pixel based on the distance between the x and y chromaticity values for each pixel and the Planckian locus;
• determine red, green, and blue adjustments for each pixel using the weight for each pixel, wherein determining red, green and blue adjustments for each pixel comprises using the weight for each pixel and the red, green and blue color data from each pixel to determine a weighted average red value, a weighted average green value, and a weighted average blue value, and adjusting the red, green and blue color data of each pixel using the corresponding weighted average values, and
• apply a white balance adjustment to the red, green and blue color data obtained from each pixel.

A process comprising:

• transforming red, green, and blue color data obtained from each pixel in a pixel array into x and y chromaticity values for each pixel;
• determining a minimum distance in (x, y) space between a Planckian locus and the x and y chromaticity values for each pixel;
• determining a weight for each pixel based on the minimum distance between its x and y chromaticity values and the Planckian locus;
• determining red, green, and blue adjustments for each pixel using the weight for each pixel, and
• applying a white balance adjustment to the red, green and blue color data obtained from each pixel.

An apparatus comprising:

• an automatic white balance (AWB) circuit coupled to a pixel array to:
• transform red, green, and blue color data obtained from each pixel into x and y chromaticity values for each pixel;
• determine a distance between a Planckian locus and the x and y chromaticity values for each pixel;
• determine a weight for each pixel based on the distance between the x and y chromaticity values for each pixel and the Planckian locus;
• determine red, green, and blue adjustments for each pixel using the weight for each pixel, wherein determining red, green and blue adjustments for each pixel comprises using the weight for each pixel and the red, green and blue color data from each pixel to determine a weighted average red value, a weighted average green value, and a weighted average blue value, and adjusting the red, green and blue color data of each pixel using the corresponding weighted average values;
• and
• apply a white balance adjustment to the red, green and blue color data obtained from each pixel.

A process comprising:

• transforming red, green, and blue color data obtained from each pixel in a pixel array into x and y chromaticity values for each pixel;
• determining a distance between a Planckian locus and the x and y chromaticity values for each pixel;
• determining a weight for each pixel based on the distance between its x and y chromaticity values and the Planckian locus;
• determining red, green, and blue adjustments for each pixel using the weight for each pixel, wherein determining red, green and blue adjustments for each pixel comprises using the weight for each pixel and the red, green and blue color data from each pixel to determine a weighted average red value, a weighted average green value, and a weighted average blue value, and adjusting the red, green and blue color data of each pixel using the corresponding weighted average values;
• and
• applying a white balance adjustment to the red, green and blue color data obtained from each pixel.