1. A method of identity verification using biometric signature data, comprising: creating a face sample database based on a plurality of acquired face samples, each of the plurality of acquired face samples including parameters for defining different postures and expressions; calculating a feature database by extracting selected features of entries in the face sample database; calculating positive samples and negative samples based on entries in the feature database; calculating a key bin feature using a learning algorithm, the key bin feature distinguishing each of the positive samples and negative samples; and calculating a classifier from the key bin feature for use in identifying and authenticating an acquired face image of a person-to-be-identified.