Method and apparatus to modify pitch estimation function in acoustic signal musical note pitch extraction
First Claim
1. A method comprising:
- initializing a function ft and a time t, where t=0, x′
0=f0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of an acoustic signal at time zero; and
determining at least one pitch estimate using the function x′
t=ft(Ft) by an iterative process of creating ft+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2, xt−
3, . . . , and functions ft(Ft), ft−
1(Ft−
1), ft−
2(Ft−
2), ft−
3(Ft−
3) . . . and incrementing t;
calculating at least one final pitch estimate; and
at least one of outputting to an input acoustic transducer, or storing in a memory, the acoustic signal processed in accordance with the 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.
28 Citations
30 Claims
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1. A method comprising:
-
initializing a function ft and a time t, where t=0, x′
0=f0(F0), x′
0 is a pitch estimate at time zero and F0 is a frequency of an acoustic signal at time zero; anddetermining at least one pitch estimate using the function x′
t=ft(Ft) by an iterative process of creating ft+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2, xt−
3, . . . , and functions ft(Ft), ft−
1(Ft−
1), ft−
2(Ft−
2), ft−
3(Ft−
3) . . . and incrementing t;calculating at least one final pitch estimate; and at least one of outputting to an input acoustic transducer, or storing in a memory, the acoustic signal processed in accordance with the at least one final pitch estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A computer-readable storage medium storing a computer program for causing the computer to perform operations that comprise:
-
initializing a function ft and a time t, where t=0, x′
0=f0(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=ft(Ft) by an iterative process of creating ft+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, xt−
2, xt−
3, . . . , and functions ft(Ft), ft−
1(Ft−
1), ft−
2(Ft−
2), ft−
3(Ft−
3) . . . and incrementing t;
calculating at least one final pitch estimate; andat least one of outputting to an input acoustic transducer, or storing in a memory, the acoustic signal processed in accordance with the at least one final pitch estimate. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A system comprising:
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an input to receive data representing an acoustic signal; and a processor to process the received data to estimate a pitch of the acoustic signal, where said processor comprises; means for initializing a function ft, and a time t, where t=0, x′
0=f0(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=ft(Ft) by an iterative process of creating ft+1(Ft+1) based at least partly on pitch estimates x′
t, x′
t−
1, x′
t−
2, x′
t−
3, . . . , and functions ft(Ft), ft−
1(Ft−
1), ft−
2(Ft−
2), ft−
3(Ft−
3) . . . and incrementing t; andmeans for determining at least one final pitch estimate (xt);
wherein the system further comprises at least one of;an output acoustic transducer coupled to the processor to output the acoustic signal processed in accordance with the at least one final pitch estimate; and at least one memory coupled to the processor for storing the acoustic signal processed in accordance with the at least one final pitch estimate. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification