Feature extraction method, comparison system, and storage medium

A feature extraction method comprising:

• by at least one processor
• determining a degree of reliability indicating a likelihood of being a recognition target, with respect to a second region extracted as a foreground region of an image, the second region within a first region extracted from the image as a partial region including the recognition target;
• determining a feature of the recognition target, based on the degree of reliability, by using a first feature extracted from the first region, and a second feature extracted from the second region;
• and
• outputting information indicating the feature of the recognition target,
• wherein the method further comprises, by the at least one processor:
• calculating a ratio of an area of the second region to an area of the first region, and
• determining the degree of reliability, based on a reliability degree determination method in which the degree of reliability is determined to be lower as the ratio becomes larger when the ratio is larger than a first predetermined value, and the degree of reliability is determined to be lower as the ratio becomes smaller when the ratio is smaller than a second predetermined value.

A non-transitory computer-readable storage medium storing a program causing a computer to execute:

• determining a degree of reliability indicating a likelihood of being a recognition target, with respect to a second region extracted as a foreground region of an image, the second region within a first region extracted from the image as a partial region including the recognition target;
• determining a feature of the recognition target, based on the degree of reliability, by using a first feature extracted from the first region, and a second feature extracted from the second region;
• and
• outputting information indicating the feature of the recognition target,
• wherein the program causes the computer to further execute:
• calculate a ratio of an area of the second region to an area of the first region, and
• determine the degree of reliability, based on a reliability degree determination method in which the degree of reliability is determined to be lower as the ratio becomes larger when the ratio is larger than a first predetermined value, and the degree of reliability is determined to be lower as the ratio becomes smaller when the ratio is smaller than a second predetermined value.