Device and method for analyzing an information signal
First Claim
1. A device, comprising:
- an extractor to provide extracted short-time spectra by extracting short-time spectra or derived short-time spectra having at least one of harmonic or percussive portions from an information signal;
a decomposer to decompose the extracted short-time spectra into component signal spectra representing profile spectra for a plurality of tone sources, the profile spectra determined in part by a reduced number of the extracted short-time spectra resulting from a weighted linear combination of the extracted short-time spectra; and
a calculator to calculate a plurality of amplitude envelopes over time on the basis of the profile spectra and the extracted short-time spectra, the plurality of amplitude envelopes corresponding to the plurality of tone sources.
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Abstract
In order to analyze an information signal, a significant short-time spectrum is extracted from the information signal, the means for extracting being configured to extract such short-time spectra which come closer to a specific characteristic than other short-time spectra of the information signal. The short-time spectra extracted are then decomposed into component signals using ICA analysis, a component signal spectrum representing a profile spectrum of a tone source which generates a tone corresponding to the characteristic sought for. From a sequence of short-time spectra of the information signal and from the profile spectra determined, an amplitude envelope is eventually calculated for each profile spectrum, the amplitude envelope indicating how a profile spectrum of a tone source all in all changes over time. The profile spectra and all the amplitude envelopes associated therewith provide a description of the information signal which may be evaluated further, for example for transcription purposes in the case of a music signal.
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Citations
20 Claims
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1. A device, comprising:
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an extractor to provide extracted short-time spectra by extracting short-time spectra or derived short-time spectra having at least one of harmonic or percussive portions from an information signal; a decomposer to decompose the extracted short-time spectra into component signal spectra representing profile spectra for a plurality of tone sources, the profile spectra determined in part by a reduced number of the extracted short-time spectra resulting from a weighted linear combination of the extracted short-time spectra; and a calculator to calculate a plurality of amplitude envelopes over time on the basis of the profile spectra and the extracted short-time spectra, the plurality of amplitude envelopes corresponding to the plurality of tone sources. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, comprising:
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extracting short-time spectra or derived short-time spectra having at least one of harmonic or percussive portions from an information signal to provide extracted short-time spectra; decomposing the extracted short-time spectra into component signal spectra representing profile spectra for a plurality of tone sources, the profile spectra determined in part by a reduced number of the extracted short-time spectra resulting from a weighted linear combination of the extracted short-time spectra; and calculating a plurality of amplitude envelopes over time on the basis of the profile spectra and the extracted short-time spectra, the plurality of amplitude envelopes corresponding to the plurality of tone sources. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A tangible computer storage medium having stored thereon a computer program which, when executed by a computer, results in the computer performing a method comprising:
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extracting short-time spectra or derived short-time spectra having at least one of harmonic or percussive portions from an information signal to provide extracted short-time spectra; decomposing the extracted short-time spectra into component signal spectra representing profile spectra for a plurality of tone sources, the profile spectra determined in part by a reduced number of the extracted short-time spectra resulting from a weighted linear combination of the extracted short-time spectra; and calculating a plurality of amplitude envelopes over time on the basis of the profile spectra and the extracted short-time spectra, the plurality of amplitude envelopes corresponding to the plurality of tone sources.
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Specification