Patent ID: 6862253

Claim:
A sonic identification system, comprising: a) an emitter, configured to broadcast ultra-sonic energy toward a subject at a variety of frequencies within a frequency range during a time interval; b) a receiver, configured to receive and detect the ultra-sonic energy reflected off of the subject, and to develop signals representing characteristics of the reflected ultra-sonic energy; and c) a microprocessor, coupled to at least one of the emitter and receiver, including: i) a pre-processor, configured to receive the signals from the receiver and to develop a new spectrogram of the subject comprising a plurality of said signals taken over the time interval; ii) a memory, configured for containing records of spectrograms related to a plurality of known subjects; and iii) a processor configured to analyze the new spectrogram using a pattern-matching algorithm, to identify invariant features of the new spectrogram, and to determine whether the identity of the subject of the new spectrogram is the same as the subject of any of the records of spectrograms stored in the memory.