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Speech analysis method and apparatus

Assignee: Individual
•
Filing: 1993-07-14
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Granted: 1994-09-06
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Expires: 2013-07-14
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Abstract

Abstract System (100) receives a speech signal at an input (102) which is measured and transformed by speech feature measuring device (104). The output feature vector from speech feature measuring device (104) is then compared to a reference model in a statistical classification manner. Acoustic similarity measuring device (106) performs statistical measurements while temporal speech model constraints block (108) imposes transitional probabilities to the probability measurements generated by measuring device (106). Acoustic similarity measuring device (106) performs a weighted analysis of the error vector defined between the speech feature vector and reference vector utilized during the analysis.

Inventors

  • 👤 George R. Doddington

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 08:51
CPC Classifications
G; G10; G10L; G10L15/00; G10L15/08; G10L15/10

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 166 words
A method of speech analysis comprising: receiving a speech signal; converting the speech signal into a converted signal for processing by a processor and memory system; generating a feature vector from said converted signal, said feature vector having a plurality of feature vector elements; providing a reference model comprising a plurality of states, each of said states comprising an associated means vector and covariance matrix; generating an error vector having a plurality of error elements, each of said error elements corresponding to one of said feature vector elements; weighting each of said error elements by a respective weight factor raised by an exponent, each respective weight factor comprising a factor proportional to a relative variance of each of said feature vector elements; generating an observation score based on said feature vector, said weighted error elements, and said reference model states; and based on a series of said observation scores, determining the probability that received speech signals correspond to a particular series of said reference model states.
Claim 2
Independent Claim 166 words
A method of speech analysis comprising: receiving a speech signal; converting the speech signal into a converted signal for processing by a processor and memory system; generating a feature vector from said converted signal, said feature vector having a plurality of feature vector elements; providing a reference model comprising a plurality of states, each of said states comprising an associated means vector and covariance matrix; generating an error vector having a plurality of error elements, each of said error elements corresponding to one of said feature vector elements; weighting each of said error elements by a respective weight factor raised by an exponent, each respective weight factor comprising a factor proportional to a relative variance of each of said feature vector elements; generating an observation score based on said feature vector, said weighted error elements, and said reference model states; and based on a series of said observation scores, determining the probability that received speech signals correspond to a particular series of said reference model states.
Claim 3
Dependent Claim 31 words
The method of claim 1 wherein said step of weighting said error elements comprises weighting only said error elements corresponding to said feature vector elements having variances below a predetermined value.
Claim 4
Dependent Claim 59 words
The method of claim 1 wherein the error vector is defined as a product of a diagonal matrix of scale factors, wherein each scale factor is a reciprocal of a square root of an eigenvalue of said covariance matrix, times an eigenvector matrix associated with said reference model, times a difference between the feature vector and said mean vector.
Claim 5
Dependent Claim 17 words
The method of claim 1, wherein said exponent is in a range of zero to negative one.
Claim 6
Dependent Claim 11 words
The method of claim 1 wherein said exponent is negative one-half.
Claim 7
Dependent Claim 56 words
The method of claim 1 wherein said weighting step yields a plurality of partial results, and said step of generating an observation score further comprises: squaring the partial results; summing the squared partial results; multiplying the summed, squared partial results times negative one-half; and adding a covariance dispersion factor to the multiplied, summed, squared partial results.
Claim 8
Independent Claim 208 words
An apparatus for performing speech analysis, comprising: circuitry for receiving a speech signal; circuitry for converting said speech signal to a converted signal for processing by a processor and memory system; circuitry for transmitting said converted signal to speech feature measuring circuitry; said speech feature measuring circuitry for generating a feature vector from said converted signal, said feature vector having a plurality of feature vector elements; a memory for storing a reference model comprising a plurality of states, each of said states comprising an associated mean vector and covariance matrix; acoustic similarity measuring circuitry, including: circuitry for generating an error vector having a plurality of error elements, each of said error elements corresponding to one of said feature vector elements; circuitry for weighting each of said error elements of the error vector by a respective weight factor raised by an exponent, each respective weight factor comprising a factor proportional to a relative variance of each of said feature vector elements; circuitry for generating an observation score based on said feature vector, said weighted error elements, and said reference model states; and circuitry for determining, based on a series of said observation scores, the probability that received speech signals correspond to a particular series of said reference model states.
Claim 9
Independent Claim 208 words
An apparatus for performing speech analysis, comprising: circuitry for receiving a speech signal; circuitry for converting said speech signal to a converted signal for processing by a processor and memory system; circuitry for transmitting said converted signal to speech feature measuring circuitry; said speech feature measuring circuitry for generating a feature vector from said converted signal, said feature vector having a plurality of feature vector elements; a memory for storing a reference model comprising a plurality of states, each of said states comprising an associated mean vector and covariance matrix; acoustic similarity measuring circuitry, including: circuitry for generating an error vector having a plurality of error elements, each of said error elements corresponding to one of said feature vector elements; circuitry for weighting each of said error elements of the error vector by a respective weight factor raised by an exponent, each respective weight factor comprising a factor proportional to a relative variance of each of said feature vector elements; circuitry for generating an observation score based on said feature vector, said weighted error elements, and said reference model states; and circuitry for determining, based on a series of said observation scores, the probability that received speech signals correspond to a particular series of said reference model states.
Claim 10
Dependent Claim 33 words
The apparatus of claim 7 wherein said circuitry for weighting said error elements comprises circuitry for weighting only said error elements corresponding to said feature vector elements having variances below a predetermined value.
Claim 11
Dependent Claim 63 words
The apparatus of claim 7 wherein said error vector is defined as a diagonal matrix of scale factors, wherein each scale factor is a reciprocal of a square root of an eigenvalue of said covariance matrix, times selected elements of an eigenvector matrix associated with said reference model, time corresponding selected elements of a difference between said feature vector and said mean vector.
Claim 12
Dependent Claim 17 words
The apparatus of claim 7 wherein said exponent is in a range of zero to negative one.
Claim 13
Dependent Claim 11 words
The apparatus of claim 7 wherein said exponent is negative one-half.

References Cited (Backward Citations)

US4032711A Cited
US4716592A Cited
US4669120A Cited
US4724535A Cited
US4741036A Cited
US5072452A Cited

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