Audio signal processing methods and systems
First Claim
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1. A method of identifying at least one fundamental frequency component of an audio signal, the method comprising receiving and recording an audio event, and converting the recorded audio event into an audio signal, the method further comprising:
- (a) filtering the audio signal to produce a plurality of sub-band time domain signals;
(b) transforming the plurality of sub-band time domain signals into a plurality of sub-band frequency domain signals by mathematical operators;
(c) summing together the plurality of sub-band frequency domain signals to yield a single spectrum;
(d) calculating the bispectrum of each of the plurality of sub-band time domain signals;
(e) summing together the bispectra calculated in (d);
(f) calculating the diagonal of the summed bispectra;
(g) multiplying the single spectrum and the diagonal of the summed bispectra to produce a product spectrum; and
(h) identifying at least one fundamental frequency component of the audio signal from the product spectrum or information contained in the product spectrum.
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Abstract
Described are methods and systems of identifying one or more fundamental frequency component(s) of an audio signal. The methods and systems may include any one or more of an audio event receiving step, a signal discretization step, a masking step, and/or a transcription step.
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Citations
21 Claims
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1. A method of identifying at least one fundamental frequency component of an audio signal, the method comprising receiving and recording an audio event, and converting the recorded audio event into an audio signal, the method further comprising:
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(a) filtering the audio signal to produce a plurality of sub-band time domain signals; (b) transforming the plurality of sub-band time domain signals into a plurality of sub-band frequency domain signals by mathematical operators; (c) summing together the plurality of sub-band frequency domain signals to yield a single spectrum; (d) calculating the bispectrum of each of the plurality of sub-band time domain signals; (e) summing together the bispectra calculated in (d); (f) calculating the diagonal of the summed bispectra; (g) multiplying the single spectrum and the diagonal of the summed bispectra to produce a product spectrum; and (h) identifying at least one fundamental frequency component of the audio signal from the product spectrum or information contained in the product spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A non-transitory computer-readable medium for identifying at least one fundamental frequency component of an audio signal or audio event, the non-transitory computer-readable medium comprising:
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code components configured to enable a computer to perform a method of identifying at least one fundamental frequency component of an audio signal, the method comprising receiving and recording an audio event, and converting the recorded audio event into an audio signal, the method further comprising; (a) filtering the audio signal to produce a plurality of sub-band time domain signals; (b) transforming the plurality of sub-band time domain signals into a plurality of sub-band frequency domain signals by mathematical operators; (c) summing together the plurality of sub-band frequency domain signals to yield a single spectrum; (d) calculating the bispectrum of each of the plurality of sub-band time domain signals; (e) summing together the bispectra calculated in (d); (f) calculating the diagonal the summed bispectra; (g) multiplying the single spectrum and the diagonal of the summed bispectra to produce a product spectrum; and (h) identifying at least one fundamental frequency component of the audio signal from the product spectrum or information contained in the product spectrum.
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Specification