System and method for tracking sound pitch across an audio signal using harmonic envelope

A system configured to analyze audio information, the system comprising:

• one or more processors configured to execute computer program modules, the modules comprising:
• an audio information module configured to obtain audio information derived from an audio signal representing one or more sounds, wherein the audio information includes audio information that corresponds to an audio signal during a first time sample window, wherein such information includes transformed audio information that specifies a magnitude of an intensity coefficient related to an intensity of the audio signal as a function of frequency during the first time sample window, wherein the audio information corresponding to the first time sample window indicates chirp likelihood as a function of fractional chirp rate, wherein the chirp likelihood for a given fractional chirp rate indicates the likelihood of the sound having the estimated pitch also having the given fractional chirp rate during the first time sample window;
• an envelope vector module configured to determine, as a function of pitch in the first time sample window, an envelope vector having coordinates, wherein the envelope vector module is configured to determine the envelope vector for a given pitch in the first time sample window based on the values for the intensity coefficient at harmonic frequencies of the given pitch in the first time sample window;
• an envelope correlation module configured to obtain an envelope vector for a sound represented by the audio signal during a second time sample window, and to determine, for the first time sample window, a correlation metric as a function of pitch, wherein the correlation metric for a given pitch in the first time sample window indicates a level of correlation between the envelope vector for the second time sample window and the envelope vector for the given pitch in the first time sample window;
• and
• a pitch estimation module configured to determine an estimated pitch for the first time sample window based on the determination of the correlation metric for the first time sample window, and wherein the pitch estimation module is further configured to determine an estimated fractional chirp rate for the first time sample window based on the estimated pitch and the chirp likelihood for the first time sample window.