1. A store system comprising: an image output section comprising at least one processor and configured to output an image captured by an image pickup section; an object recognizing section configured to recognize a plurality of objects which are commodities of a same kind by reading a feature value of the image; a similarity determining section configured to calculate a similarity value indicating a degree to which an object, of the plurality of objects which are commodities of the same kind, is similar to a reference image of the object determined in advance and determine whether the similarity value exceeds a threshold value set in advance; and a defective informing section configured to inform, in response to the similarity determining section determining that the similarity value does not exceed the threshold value, that the object is not recognized as a regular commodity, wherein in response to the similarity determining section determining that the similarity value of the object does not exceed the threshold value, the defective informing section modifies the image to graphically distinguish the object, the similarity value of which does not exceed the threshold value, from other objects of the plurality of objects which are commodities of the same kind having similarity values that exceed the threshold value, and informs that the object is not recognized as the regular commodity.