US Patent 7184079 White balance adjustment method, image processing apparatus and electronic camera

An image-capturing device captures a subject image through an exchangeable lens. A white balance sensor that is set at a position conjugate with the position of the image-capturing device relative to the exchangeable lens to receive the light from the subject image and outputs color signals. A white balance adjustment signal calculation circuit calculates white balance adjustment basic signals based upon the color signals output from the white balance sensor and weighting points in conformance to the photographic range, the number of sets of red color data and the subject brightness value. Adjustment signals to be used for white balance adjustment are determined based upon the weighting points and the adjustment basic signals.