An information processing device extracts, from an image taken by an imaging device, a human area in which it is determined that a human is present, acquires a representative value of first feature values, the first feature values being calculated by inputting, to a conversion function, each color of pixels included in a part of the human area, corrects, based on the representative value, a skin range indicating that a color indicated by a feature value acquired with the conversion function is a color of human skin, and determines whether a human is present in a part of the image acquired by the imaging device, based on whether a second feature value calculated with the conversion function for each of a plurality of pixels forming the part of the image is within the corrected skin range.