Abstract: Technologies for learning body part geometry are described. In some embodiments the technologies include systems, methods and computer readable medium for extracting biometric information from a body part of a user, such as the user's hand. In some instances the extraction is performed with the aid of a calibrated computer model of the body part in question. Body part information may be saved in a data structure for use as a biometric template. The Biometric authentication processes utilizing the technologies are also described.