Multi-illumination white balance circuit with thumbnail image processing

A method for image processing, the method comprising:

• determining a set of initial weights for a source pixel in a version of a thumbnail image by determining component values for a plurality of color channels of the source pixel;
• determining a set of weights for the source pixel in a weight map for the version of the thumbnail image, each weight in the set of weights determined based on corresponding initial weights from the set of initial weights, each weight in the set of weights representing an intensity level of a respective chrominance class of a plurality of chrominance classes for the source pixel;
• and
• applying the set of weights to values of the plurality of color channels of the source pixel to generate color component values of the plurality of color channels of a target pixel in a target thumbnail image.

An image processing circuit, comprising:

• a thumbnail image processing circuit including:
• a weights determination circuit configured to determine a set of initial weights for a source pixel in a version of a thumbnail image by determining component values for a plurality of color channels of the source pixel,
• a weight map calculation circuit coupled to the weights determination circuit and configured to determine a set of weights for the source pixel in a weight map for the version of the thumbnail image, each weight in the set of weights determined based on corresponding initial weights from the set of initial weights, each weight in the set of weights representing an intensity level of a respective chrominance class of a plurality of chrominance classes for the source pixel, and
• a target thumbnail generator circuit coupled to the weight map calculation circuit and configured to apply the set of weights to values of the plurality of color channels of the source pixel to generate color component values of the plurality of color channels of a target pixel in a target thumbnail image;
• and
• a reintegration circuit coupled to the thumbnail image processing circuit and configured to:
• apply the weight map to a set of coefficients to generate a weighted set of coefficients, and
• apply the weighted set of coefficients to pixel values in an input image to generate an output image.