Image converting method and device

An image converting device comprising:

• a JND corresponding value width acquisition unit configured to, on the basis of input image data, acquire a JND corresponding value width corresponding to a reflectance component of the input image data;
• a luminance width acquisition unit configured to acquire a luminance width corresponding to the JND corresponding value width or a value obtained by converting the JND corresponding value width in accordance with a predetermined rule using, as a reference, a second reference luminance different from a first reference luminance, wherein the first reference luminance is used as a reference when acquiring the JND corresponding value width;
• a corrected reflectance component acquisition unit configured to acquire a gradation width corresponding to the luminance width as a corrected reflectance component;
• and
• a mixer configured to generate output image data by mixing an illumination light component of the input image data or a corrected illumination light component thereof and the corrected reflectance component.