1. A date identification apparatus comprising: an isolator that isolates, out of image data generated through capturing of an image of a medium to which a date is assigned using seven-segment characters, date area data to which the date is estimated to be assigned; a binarization converter that binarizes the date area data using a threshold based on luminance and hue; a labeler that subjects the binarized date area data to labeling to extract target area data that is identifiable as a numeral; a numeral identifier that performs a histogram on at least the target area data using a plurality of lines and identifies a numeral on a basis of a peak count in each of the lines; and a date data assigner that assigns date data based on the identified numeral to the image data.