this document shows how to normalize illumination and reducing the negative effects of illumination on face recognition.

Logarithm transform is the preprocessing techniques used to normalize the illumination variation. In the log domain the re ectance and illumination of the image can be easily

对彩色图像进行归一化，消除由于光照不均造成的色差。-The color image normalization, to eliminate the chromatic aberration caused due to the uneven illumination.