[Problem] To provide an image processing device for highlighting changes in the color of mucosa, and the like, that can occur with atrophy of the stomach resulting from atrophic gastritis, an operation method for the imaging processing device, and an image processing program. [Solution] An endoscope image is acquired that is formed by an image signal which includes a narrow band image signal. The lightness, hue, and saturation levels of the pixels forming the endoscope image are each calculated. The difference between the hue of a reference color representing a normal area and the hue of the pixels of the endoscope image is modified, with the hue of the reference color as the center, such that the hue H of the pixels becomes a hue H+ΔH distant from the hue of the reference color. The difference between the saturation of the reference color, which is determined in accordance with the lightness level of the pixels of the endoscope image, and the saturation of the pixels is modified, with the saturation of the reference color as the center, such that the saturation S of the pixels becomes a saturation S+ΔS distant from the saturation of the reference color. The lightness level of the pixels of the endoscope image is set to the original lightness level, and the image is output using color having the altered hue and saturation.La présente invention vise à fournir un dispositif de traitement d'image permettant de mettre en évidence des changements de couleur d'une muqueuse, et similaire, qui peut se produire avec une atrophie de l'estomac résultant d'une gastrite atrophique ； un procédé de fonctionnement pour le dispositif de traitement d'imagerie et un programme de traitement d'image. Une image endoscopique est acquise, qui est formée par un signal d'image qui comprend un signal d'image à bande étroite. La luminosité, la teinte et les niveaux de saturation des pixels formant l'image endoscopique sont tous calculés. La différence entre la teinte d'une couleur de référence
