US6278970B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speech transformation using log energy and orthogonal matrix
Assignee: British Telecommunications PLC
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Filing: 1997-03-25
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Granted: 2001-08-21
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Expires: 2017-03-25
Abstract
Abstract Calculate the log frame energy value of each of a pre-determined number n of frames of an input speech signal and apply a matrix transform to the n log frame energy values to form a temporal matrix representing the input speech signal. The matrix transform may be a discrete cosine transform.
Inventors
- 👤 Benjamin P Milner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:12
CPC Classifications
G; G10; G10L; G10L15/00; G10L15/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
90 words
A method of generating features for use with speech responsive apparatus, said method comprising: calculating the logarithmic frame energy value of each of a sequence of a predetermined number n of frames of an input speech signal; and applying a predetermined orthogonal transform matrix to the n logarithmic frame every values to form a frame energy vector representing the input speech signal, wherein the predetermined orthogonal transform matrix encodes temporal information such that the elements of the off-diagonal of the covariance matrix of the frame energy vector are substantially zero.
Claim 2
Independent Claim
90 words
A method of generating features for use with speech responsive apparatus, said method comprising: calculating the logarithmic frame energy value of each of a sequence of a predetermined number n of frames of an input speech signal; and applying a predetermined orthogonal transform matrix to the n logarithmic frame every values to form a frame energy vector representing the input speech signal, wherein the predetermined orthogonal transform matrix encodes temporal information such that the elements of the off-diagonal of the covariance matrix of the frame energy vector are substantially zero.
Claim 3
Dependent Claim
19 words
A method as in claim 1 wherein successive sequences represent overlapping groups of n frames of the input signal.
Claim 4
Dependent Claim
18 words
A method as in claim 1 , wherein the predetermined orthogonal transform matrix represents a discrete cosine transform.
Claim 5
Dependent Claim
21 words
A method as in claim 1 , wherein the temporal matrix is truncated so as to include fewer than n elements.
Claim 6
Independent Claim
122 words
A method of speech recognition comprising: receiving an input signal representing speech, said input signal being divided into frames; generating a feature by calculating the logarithmic frame energy value of each of a predetermined number n frames of the input speech signal; applying a predetermined orthogonal transform matrix to the n logarithmic frame energy values to form a frame energy vector representing the input speech signal, the predetermined orthogonal transform matrix encoding temporal information such that the elements of the off-diagonal of the covariance matrix of the frame energy vector are substantially zero; comparing the generated feature with recognition data representing allowed utterances, said recognition data relating to the feature; and indicating recognition or otherwise on the basis of the comparison step.
Claim 7
Independent Claim
122 words
A method of speech recognition comprising: receiving an input signal representing speech, said input signal being divided into frames; generating a feature by calculating the logarithmic frame energy value of each of a predetermined number n frames of the input speech signal; applying a predetermined orthogonal transform matrix to the n logarithmic frame energy values to form a frame energy vector representing the input speech signal, the predetermined orthogonal transform matrix encoding temporal information such that the elements of the off-diagonal of the covariance matrix of the frame energy vector are substantially zero; comparing the generated feature with recognition data representing allowed utterances, said recognition data relating to the feature; and indicating recognition or otherwise on the basis of the comparison step.
Claim 8
Dependent Claim
20 words
A method of speech recognition as in claim 5 wherein the predetermined orthogonal transform matrix represents a discrete cosine transform.
Claim 9
Dependent Claim
94 words
Feature generating apparatus for use with speech responsive apparatus, said feature generating apparatus comprising: a processor for calculating the logarithm of the energy of each of a predetermined number n of frames of an input speech signal; and a processor for applying a predetermined orthogonal transform matrix to the n logarithmic energy values so calculated to form a frame energy vector representing the input speech signal, the predetermined orthogonal transform matrix encoding temporal information such that the elements of the off diagonal of the covariance matrix of the frame energy vector are substantially zero.
Claim 10
Dependent Claim
94 words
Feature generating apparatus for use with speech responsive apparatus, said feature generating apparatus comprising: a processor for calculating the logarithm of the energy of each of a predetermined number n of frames of an input speech signal; and a processor for applying a predetermined orthogonal transform matrix to the n logarithmic energy values so calculated to form a frame energy vector representing the input speech signal, the predetermined orthogonal transform matrix encoding temporal information such that the elements of the off diagonal of the covariance matrix of the frame energy vector are substantially zero.
Claim 11
Dependent Claim
19 words
Feature generating apparatus as in claim 7 in which the predetermined orthogonal transform matrix represents a discrete cosine transform.
Claim 12
Dependent Claim
12 words
Speech recognition apparatus including feature generating apparatus as in claim 7 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-20 | 2005-02-19 | 2005-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-20 | 2009-02-19 | 2009-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-20 | 2013-02-19 | 2013-08-21 | $7700.00 | Window Closed / Lapsed |