Automatic speaker verification systems employing moment invariants

Claim 1

The method of verifying the identity of a person by the use of utterance comparisons comprising the steps of: a. computing an utterance vector from samples of the person's speech; b. computing an utterance vector from samples of an imposter's speech; c. analyzing the computed utterance vector of the person and the computed utterance vector of the imposter for deriving weighting factors indicative of the differences therebetween; d. recording the person's computed utterance vector and said weighting factors on a security card that is issued to said person; e. comparing the utterance vector recorded on said security card against a most recent computed utterance vector from the person for determining the differences therebetween; f. comparing the differences determined in step (e) with said recorded weighting factors and verifying the identity of said person if the comparison is within a first range and rejecting the identity of said person if the comparison is within a second range.

Claim 2

The method of verifying the identity of a person by the use of utterance comparisons comprising the steps of: a. computing an utterance vector from samples of the person's speech; b. computing an utterance vector from samples of an imposter's speech; c. analyzing the computed utterance vector of the person and the computed utterance vector of the imposter for deriving weighting factors indicative of the differences therebetween; d. recording the person's computed utterance vector and said weighting factors on a security card that is issued to said person; e. comparing the utterance vector recorded on said security card against a most recent computed utterance vector from the person for determining the differences therebetween; f. comparing the differences determined in step (e) with said recorded weighting factors and verifying the identity of said person if the comparison is within a first range and rejecting the identity of said person if the comparison is within a second range.

Claim 4

The method of verifying the identity of a person by the use of reference utterances comprising: a. computing said reference utterance from sets of moment invariants developed from a plurality of different utterances of a phrase by said person; b. computing a plurality of imposter utterance vectors from sets of moment invariants developed from a plurality of different utterances of a phrase by a plurality of imposters; c. computing an error weighting function of the differences between said reference utterance and said imposter utterance and setting a threshold for acceptance of verification as a function of error in verification; and d. verifying the identity of said person when the reference utterance is above the set threshold.

Claim 5

The method of verifying the identity of a person by the use of reference utterances comprising: a. computing said reference utterance from sets of moment invariants developed from a plurality of different utterances of a phrase by said person; b. computing a plurality of imposter utterance vectors from sets of moment invariants developed from a plurality of different utterances of a phrase by a plurality of imposters; c. computing an error weighting function of the differences between said reference utterance and said imposter utterance and setting a threshold for acceptance of verification as a function of error in verification; and d. verifying the identity of said person when the reference utterance is above the set threshold.

Claim 9

A system for verifying the identity of an electrical signal comprising: means for providing a representation of sampled amplitude values of said electrical signal; means for computing moment invariants from said sampled amplitude values; storage means for storing a plurality of computed moment invariants representative of imposter electrical signals; analyzing means for computing weighting functions indicative of the differences between computed imposter moment invariants and the first named computed moment invariants; recording means for recording the computed first named moment invariants and the weighting functions therefor; and means for accepting the identity of said electrical signal when moment invariants computed from a non-recorded electrical signal compare with the recorded moment invariants within limits established by said weighting functions.

Claim 10

A system for verifying the identity of an electrical signal comprising: means for providing a representation of sampled amplitude values of said electrical signal; means for computing moment invariants from said sampled amplitude values; storage means for storing a plurality of computed moment invariants representative of imposter electrical signals; analyzing means for computing weighting functions indicative of the differences between computed imposter moment invariants and the first named computed moment invariants; recording means for recording the computed first named moment invariants and the weighting functions therefor; and means for accepting the identity of said electrical signal when moment invariants computed from a non-recorded electrical signal compare with the recorded moment invariants within limits established by said weighting functions.

Claim 11

A system for verifying the identity of a person from an utterance of a reference phrase comprising: a. means for transforming said uttered reference phrase into electrical signals; b. means for sampling said electrical signals and for converting the samples into amplitude values; c. means for operating upon said amplitude values for computing identity moment invariants of said amplitude values; d. means for storing said identity moment invariants; e. means for storing a plurality of moment invariants corresponding to reference phrases uttered by imposters; f. analyzing means operatively connected to said means for storing said identity moment invariants and said means for storing a plurality of imposter moment invariants for deriving factors indicative of the differences therebetween; and g. means for recording said identity moment invariants and said derived factors whereby identity of a person is established by comparing the computed identity moment invariants of a reference phrase uttered at a later time against the recorded identity moment invariant when the differences therebetween compare favorably with said derived factors.

Claim 12

A system for verifying the identity of a person from an utterance of a reference phrase comprising: a. means for transforming said uttered reference phrase into electrical signals; b. means for sampling said electrical signals and for converting the samples into amplitude values; c. means for operating upon said amplitude values for computing identity moment invariants of said amplitude values; d. means for storing said identity moment invariants; e. means for storing a plurality of moment invariants corresponding to reference phrases uttered by imposters; f. analyzing means operatively connected to said means for storing said identity moment invariants and said means for storing a plurality of imposter moment invariants for deriving factors indicative of the differences therebetween; and g. means for recording said identity moment invariants and said derived factors whereby identity of a person is established by comparing the computed identity moment invariants of a reference phrase uttered at a later time against the recorded identity moment invariant when the differences therebetween compare favorably with said derived factors.

Claim 15

A system for verifying the identity of an individual by comparing the individual's previously recorded utterance against a non-recorded utterance and verifying the individual's identity if the comparison is favorable, said system comprising: means for providing a representation of sampled amplitude values of the individual's utterance; means for computing moment invariants from said sampled amplitude values; storage means for storing a plurality of computed moment invariants representative of imposter utterances; analyzing means for computing weighting functions indicative of the differences between computed imposter moment invariants and computed individual moment invariants; recording means for recording the computed individual moment invariants and the weighting functions therefor; and means for accepting the identity of said individual when moment invariants computed from an individual's non-recorded utterance compare with the recorded moment invariants within limits established by said weighting functions.

Claim 16

A system for verifying the identity of an individual by comparing the individual's previously recorded utterance against a non-recorded utterance and verifying the individual's identity if the comparison is favorable, said system comprising: means for providing a representation of sampled amplitude values of the individual's utterance; means for computing moment invariants from said sampled amplitude values; storage means for storing a plurality of computed moment invariants representative of imposter utterances; analyzing means for computing weighting functions indicative of the differences between computed imposter moment invariants and computed individual moment invariants; recording means for recording the computed individual moment invariants and the weighting functions therefor; and means for accepting the identity of said individual when moment invariants computed from an individual's non-recorded utterance compare with the recorded moment invariants within limits established by said weighting functions.

Claim 19

A system for verifying the identity of a person by the use of utterance comparisons comprising: means for converting an utterance into a corresponding electrical signal; means for providing representations of sampled amplitude values of said corresponding electrical signals; means for computing moment invariants from said provided representations; memory means for storing said computed moment invariants; means for storing a plurality of computed moment invariants corresponding to imposter utterances; analyzing means for computing weighting functions indicative of the differences between the moment invariants of the person to be identified and those of an imposter; means for comparing subsequent computed moment invariants of the person against previously computed moment invariants for providing representations of the differences therebetween; and means for comparing said provided difference representations against said computed weighting functions and for providing an acceptance indication when said differences are within acceptable magnitudes.

Claim 20

A system for verifying the identity of a person by the use of utterance comparisons comprising: means for converting an utterance into a corresponding electrical signal; means for providing representations of sampled amplitude values of said corresponding electrical signals; means for computing moment invariants from said provided representations; memory means for storing said computed moment invariants; means for storing a plurality of computed moment invariants corresponding to imposter utterances; analyzing means for computing weighting functions indicative of the differences between the moment invariants of the person to be identified and those of an imposter; means for comparing subsequent computed moment invariants of the person against previously computed moment invariants for providing representations of the differences therebetween; and means for comparing said provided difference representations against said computed weighting functions and for providing an acceptance indication when said differences are within acceptable magnitudes.