Method and apparatus to modify pitch estimation function in acoustic signal musical note pitch extraction
First Claim
1. A method to estimate pitch in an acoustic signal, comprising:
- initializing a function ƒ
t and a time t, where t=0, x′
0=ƒ
0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of the acoustic signal at time zero;
determining at least one pitch estimate using the function x′
t=ƒ
t(Ft) by an iterative process of creating ƒ
t+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2,xt−
3. . . and functions ƒ
t(Ft), ƒ
t−
1(Ft−
1), ƒ
t−
2(Ft−
2), ƒ
t−
3(Ft−
3) . . . and incrementing t; and
calculating at least one final pitch estimate.
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Abstract
In one aspect thereof this invention provides a method to estimate pitch in an acoustic signal. The method includes initializing a function ƒt and a time t, where t=0, x′0=ƒ0(F0), x′0 is a pitch estimate at time zero and F0 is a frequency of the acoustic signal at time zero; determining at least one pitch estimate using the function x′t=ƒt(Ft) by an iterative process of creating ƒt+1(Ft+1) based at least partly on pitch estimates x′t, x′t−1, x′t−2, x′t−3, . . . , and functions ƒt(Ft), ƒt−1(Ft−1), ƒt−2(Ft−2), ƒt−3(Ft−3) . . . and incrementing t; and calculating at least one final pitch estimate. Embodiments of this invention can be applied to pitch extraction with various different input acoustic signal characteristics, such as just intonation, pitch shift in the frequency domain, and non-12-step-equal-temperament tuning.
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Citations
30 Claims
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1. A method to estimate pitch in an acoustic signal, comprising:
-
initializing a function ƒ
t and a time t, where t=0, x′
0=ƒ
0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of the acoustic signal at time zero;
determining at least one pitch estimate using the function x′
t=ƒ
t(Ft) by an iterative process of creating ƒ
t+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2,xt−
3. . . and functions ƒ
t(Ft), ƒ
t−
1(Ft−
1), ƒ
t−
2(Ft−
2), ƒ
t−
3(Ft−
3) . . . and incrementing t; and
calculating at least one final pitch estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15)
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12. A computer-readable storage medium storing a computer program for causing the computer to estimate pitch in an acoustic signal by operations of:
-
initializing a function ƒ
t and a time t, where t=0, x′
0=ƒ
0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of the acoustic signal at time zero;
determining at least one pitch estimate using the function x′
t=ƒ
t(Ft) by an iterative process of creating ƒ
t+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, xt−
2, xt−
3, . . . , and functions ƒ
t(Ft), ƒ
t−
1(Ft−
1), ƒ
t−
2(Ft−
2), ƒ
t−
3(Ft−
3) . . . and incrementing t; and
calculating at least one final pitch estimate. - View Dependent Claims (13, 16, 17, 18, 19, 20, 21, 22)
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23. A system comprising means for receiving data representing an acoustic signal and processing means to process the received data to estimate a pitch of the acoustic signal, where said processing means comprises means for initializing a function ƒ
-
t, and a time t, where t=0, x′
0=ƒ
0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of the acoustic signal at time zero;
means for determining at least one pitch estimate using the function x′
t=ƒ
t(F0) by an iterative process of creating ƒ
t+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2, x′
t−
3, . . . , and functions ƒ
t(Ft), ƒ
t−
1(Ft−
1), ƒ
t−
2(Ft−
2), ƒ
t−
3(Ft−
3) . . . and incrementing t; and
means for determining at least one final pitch estimate (xt). - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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t, and a time t, where t=0, x′
Specification