Patent attributes
A white balance controlling apparatus can discriminate a green subject under a light source of the sun and a white subject under a fluorescent light source without the addition of a new color filter. The maximum or average value of luminance at a first portion of an image signal for one frame or field which includes pixels discriminated as pixels of green under a light source of the sun or white under a fluorescent light source is compared with that at any other portion of the image signal. If the maximum or average value of luminance at the first portion is either lower or higher than that at the other portion, then it is estimated that either a light source of the sun or a fluorescent light source is used.