System and method for tracking sound pitch across an audio signal using harmonic envelope
First Claim
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1. 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.
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Abstract
A system and method may be configured to analyze audio information derived from an audio signal. The system and method may track sound pitch across the audio signal. The tracking of pitch across the audio signal may take into account change in pitch by determining at individual time sample windows in the signal duration an estimated pitch and a representation of harmonic envelope at the estimated pitch. The estimated pitch and the representation of harmonic envelope may then be implemented to determine an estimated pitch for another time sample window in the signal duration with an enhanced accuracy and/or precision.
35 Citations
12 Claims
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1. 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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computer-implemented method of analyzing audio information, the method being implemented in a computer system that includes one or more physical processors, the method comprising:
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obtaining, at the one or more processors, 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, and 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; determining, at the one or more processors as a function of pitch in the first time sample window, an envelope vector having coordinates, wherein determination of the coordinates of the envelope vector for a given pitch in the first time sample window is based on the values for the intensity coefficient at harmonic frequencies of the given pitch in the first time sample window; obtaining, at the one or more processors, an envelope vector for a sound represented by the audio signal during a second time sample window; determining, at the one or more processors 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; determining, at the one or more processors, an estimated pitch for the first time sample window based on the determination of the correlation metric for the first time sample window; and determining 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. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification