Image processing method and device for performing grayscale conversion, and image processing program

摘要

Disclosed are an image processing method and device and an image processing program that are able to perform gradation conversion—that achieves a favorable saturation reproduction when exchanging and reproducing images between devices or between color spaces having different dynamic ranges—by element of having: a first gradation conversion that, when converting gradation characteristics of image data of an image, converts first gradation characteristics using a one-dimensional first lookup table corresponding to the RGB pixel data of the image; and a second gradation conversion that converts the RGB pixel data of the image to chromaticity data and luminescence data or lightness data, and that converts second gradation characteristics of the converted luminescence data or lightness data using a one-dimensional second lookup table corresponding to the luminescence data or lightness data; and then weighting the first gradation conversion and the second gradation conversion.