Patent ID: 7081923

Claim:
A method for adjusting image brightness comprising the steps of: effecting a computation on color image data represented by a color signal composed of at least three components to obtain pixel lightness components and an average brightness of an image; adjusting brightness of the image represented by the color image data based on the lightness components; and adjusting the brightness of the image represented by the color image data based on the average brightness of the image, wherein the average brightness of the image is adjusted with color saturation components of the pixels, and wherein the step of adjusting the brightness of the image represented by the color image data based on color saturation components of the pixels is effected by computing weighted lightness components by weighting the lightness components of the pixels by the color saturation components of the pixels, computing mean values of the weighted lightness components, and adjusting the brightness by converting the color image data to make the mean values desired values.