Image processing device, image processing method, and recording medium

An image processing method comprising:

• calculating a first similarity score group and m second similarity score groups, the first similarity score group including n similarity scores indicating similarity between a first face image corresponding to a face image of a target person and each of n (n≥2) face images, the m second similarity score groups including n similarity scores indicating similarity between m second face images and each of the n face images, the m second face images being obtained by converting an attribute of the first face image by individually applying m (m≥2) conversion methods to the first face image;
• acquiring a first score distribution and m second score distributions, the first score distribution indicating a distribution state of at least a part of the similarity scores in the first similarity score group, the m second score distributions indicating a distribution state of at least a part of the similarity scores in each of the m second similarity score groups;
• acquiring at least one conversion parameter corresponding to at least one conversion method from among the m conversion methods based on comparison results between the first score distribution and the m second score distributions, and
• generating a face image by converting the attribute of the first face image based on the conversion parameter.

A non-transitory computer-readable recording medium recording a program, the program causing a computer to execute processing comprising:

• calculating a first similarity score group and m second similarity score groups, the first similarity score group including n similarity scores indicating similarity between a first face image corresponding to a face image of a target person and each of n (n≥2) face images, the m second similarity score groups including n similarity scores indicating similarity between m second face images and each of the n face images, the m second face images being obtained by converting an attribute of the first face image by individually applying m (m≥2) conversion methods to the first face image;
• acquiring a first score distribution and m second score distributions, the first score distribution indicating a distribution state of at least a part of the similarity scores in the first similarity score group, the m second score distributions indicating a distribution state of at least a part of the similarity scores in each of the m second similarity score groups;
• acquiring at least one conversion parameter corresponding to at least one conversion method from among the m conversion methods based on comparison results between the first score distribution and the m second score distributions, and
• generating a face image by converting the attribute of the first face image based on the conversion parameter.