This application relates to a method and a structure for generating a picture compensation signal, and a restoring system. A center luminance value is obtained by means of an image capturing device; then a grayscale percentage value is set by means of a calculating module, and luminance is adjusted according to the grayscale percentage value; a luminance value is obtained by means of the image capturing device according to the grayscale percentage value; a luminance difference value is obtained by means of a luminance difference detection module; and whether the luminance difference value is less than a default value is determined by a difference determining module; if the luminance difference value is less than the default value, a grayscale percentage value is reduced by the calculating module, and comparison again; and if the luminance difference value exceeds the default value, a sampling grayscale is obtained by a processing module.