Patent ID: 7613338

Claim:
An image processing method performed by an image processing system, said method comprising: a luminance level extraction step of extracting, with the image processing system, luminance components from image data; a scale conversion step of obtaining, with the image processing system, on a predetermined scale a distribution of the luminance components extracted in the luminance level extraction step; a luminance level enhancement step of setting, with the image processing system, a middle luminance value for the image data, correcting a luminance value larger than the middle luminance value in the luminance distribution converted in the scale conversion step so as to decrease a luminance value before scale conversion that corresponds to the larger luminance value, and correcting a luminance value smaller than the middle luminance value so as to increase a luminance value before scale conversion that corresponds to the smaller luminance value; and an image reproduction step of reproducing, with the image processing system, the image data by using the luminance distribution enhanced in the luminance level enhancement step as a new image luminance distribution, wherein in the luminance level enhancement step, letting A be a luminance component value output in the luminance level extraction step, B be a luminance component value output in the scale conversion step, C be the middle luminance, and D and E be luminance level enhancement parameters, a luminance level is converted on the basis of a characteristic given by for B≦C , ( C/B ) D ·A for B>C, 1−{(1 −C )/(1 −B )} E ·(1 −A ).