1. A processing system relating to an image feature, the processing system comprising: an input unit which receives an input of a plurality of sample images obtained by capturing an object associated with a category in different conditions with respect to a plurality of the categories; and a generation unit which generates likelihood distribution information in which each value representing a possible feature of each pixel or each pixel block, and each value representing a likelihood belonging to each of the categories are associated with each other, based on a feature of each pixel or each pixel block included in an area relating to each of the objects within the plurality of sample images associated with a category.