US 5,414,755 A · System and method for passive voice verification in a telephone network

Abstract

A telephone long distance service is provided using speaker verification to determine whether a user is a valid user or an impostor. The user claims an identity by offering some form of identification, typically by entering a calling card number on the phone's touch-tone keypad or by a magnetic strip on the card which is read by the telephone. Unrestricted, extemporaneous speech of a group of customers are digitized, analyzed in accordance with a PCM circuit, and characterized as a non-parametric set of speech feature vectors. The extemporaneous speech of the long distance telephone service user claiming the identity of a service customer via his card number is digitized and analyzed in a like manner. The identity of the user is verified by comparing, either during or after the call, the signals in accordance with an algorithm which compares a reference utterance of a known customer with input utterances from one or more unknown telephone service users, one of which users has claimed the identity of the customer. This comparison results in a decision to accept or reject the hypothesized identity. The identity hypothesis to be tested is thus derived from the calling card of the customer.

Claims21

Dependent claims

A method of verifying that a person using a telephone network has an identity corresponding to one of a plurality of previously established identities, comprising the steps of:

storing reference frames of speech for a plurality of persons, each of said persons being associated with one of said plurality of previously established identities, each said speech frame including a plurality of speech feature vectors, said speech feature vectors being non-parametric in nature;
establishing a claimed identity for a person seeking verification;
passively monitoring a conversation via said telephone network between said person seeking verification and a called party to obtain a sample of said person's speech, said speech sample being thereafter processed into frames of speech;
and
comparing said sample with at least one reference set to determine whether said person seeking verification corresponds to said claimed identity, wherein said comparison includes generating a match score derived from a determination of nearest neighbor Euclidean distance between frames of speech associated with said speech sample and frames of said reference speech.

2 more elements

An apparatus for verifying that a person using a telephone network has an identity corresponding to one of a plurality of previously established identities, comprising:

means for storing reference frames of speech for a plurality of persons, each of said persons being associated with one of said plurality of previously established identities, each said speech frame including a plurality of speech feature vectors, said speech feature vectors being non-parametric in nature;
means for establishing a claimed identity for a person seeking verification;
means for passively monitoring a conversation via said telephone network between said person seeking verification and a called party to obtain a sample of said person's speech, said speech sample being thereafter processed into frames of speech;
and
means for comparing said sample with at least one reference set to determine whether said person seeking verification corresponds to said claimed identity, including means for generating a match score derived from a determination of nearest neighbor Euclidean distance between frames of speech associated with said speech sample and frames of said reference speech.

2 more elements

Dependencies are inferred from the claim text.

System and method for passive voice verification in a telephone network

Life of this patent

System and method for passive voice verification in a telephone network

Life of this patent

Abstract

Claims21