The disclosure is an information processing device including: a memory; and at least one processor coupled to the memory and performing operations. The operations includes: generating, based on a target image including a target and a standard image not including the target, a target structure image indicating a shape feature of an object included in the target image and a standard structure image indicating a shape feature of an object included in the standard image, in each of a plurality of imaging conditions; calculating an individual difference being a difference between the target structure image and the standard structure image, and a composite difference based on the individual differences; calculating an individual smoothness being a smoothness of the target structure image, and a composite smoothness based on the individual smoothness; and generating a silhouette image of the target, based on the composite difference and the composite smoothness.