IMAGE PROCESSING DEVICE AND AUTO WHITE BALANCING METHOD

An auto white balancing method for image data includes calculating block variances for the image data and selecting blocks having a block variance higher than a block variance value. The method further includes selecting patches included in a gray zone defined at a color space, applying a corresponding block variance as a weight to the patches of the gray zone, adjusting a first mean value at the color space, and selecting first patch candidates belong to a first distribution at a luminance domain from among patches selected with reference to the adjusted first mean value. The method further includes selecting a shrunken gray zone corresponding to an anchor point in the gray zone and selecting second patch candidates having a second distribution at a color space and a luminance domain, from among patches included in the shrunken gray zone, and calculating a final gain for the image data by combining a first RGB gain and a second RGB gain respectively extracted from the first patch candidates and the second patch candidates.