1. An information processing apparatus comprising: learning means for performing Adaptive Boosting Error Correcting Output Coding learning using image feature values of a plurality of sample images each being assigned a class label to generate a multi-class classifier configured to output a multi-dimensional score vector corresponding to an input image; registration means for inputting a register image to the multi-class classifier, and registering a multi-dimensional score vector corresponding to the input register image in association with identification information about the register image; and determination means for inputting an identification image to be identified to the multi-class classifier, and determining a similarity between a multi-dimensional score vector corresponding to the input identification image and the registered multi-dimensional score vector corresponding to the register image.