1. An apparatus for generating a representative image representing a case and radiographic interpretation information for each case from medical images based on past cases, comprising: a wavelet feature calculation unit configured to calculate wavelet features of a plurality of images that have been taken and stored in the past; a keyword extraction unit configured to extract a keyword included in radiographic interpretation information for each of the stored images; an information storage unit configured to store the calculated wavelet features and the extracted keywords in association with the respective stored images; a group generation unit configured to classify the stored images on the basis of the extracted keywords to generate a plurality of groups; a centroid vector calculation unit configured to calculate, for each of the generated groups, a centroid vector of wavelet feature-based feature vectors of respective images corresponding to the keywords included in that group; a spatial distance calculation unit configured to calculate, for each of the groups, a spatial distance between the calculated centroid vector and each of the wavelet feature-based feature vectors of the respective images corresponding to the keywords included in that group; and a representative image storage unit configured to store, for each of the groups, the image for which the calculated spatial distance is the shortest and the radiographic interpretation information associated with the image as a representative image of that group.