Data processing: speech signal processing – linguistics – language – Speech signal processing – Application
Reexamination Certificate
2000-03-15
2003-01-21
McFadden, Susan (Department: 2654)
Data processing: speech signal processing, linguistics, language
Speech signal processing
Application
C704S246000, C704S270000
Reexamination Certificate
active
06510415
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a voice authentication method and a system utilizing same and, more particularly, to a system and method which compare a voice print of a user with each of a plurality of stored voice prints of known individuals, and provide authentication only if the user voice print is most similar to a stored voice print of an individual the user claims to be among all other stored voice prints.
The use of various types of methods to secure systems from unauthorized access is common practice in financial institutions, banks, electronic commerce Internet sites, computer networks and the like.
Currently available physical authentication devices which are frequently used to access secure systems, such as crypto cards, limited access cards, or keys, provide low security protection, since such devices can be lost, stolen, loaned to an unauthorized individual and/or duplicated.
Another and more sophisticated approach for authentication, which is used to provide higher security protection, is known in the art as biometric authentication. Biometric authentication involves identification of unique body characteristics, such as, fingerprints, retinal scans, facial recognition and voice pattern authentication.
Retinal scanning is based on the fact that retinal blood vessel patterns are unique and do not change over lifetime. Although this feature provides high degree of security, retinal scanning has limitations since it is expensive and requires complicated hardware and software for implementation.
Finger printing and facial recognition also requires expensive and complicated hardware and software for implementation.
Voice verification, which is also known as voice authentication, voice pattern authentication, speaker identity verification and voice print, is used to provide a speaker's identification. Voice pattern authentication differs from voice pattern recognition. In voice pattern recognition, or speech recognition the speaker utters a phrase (e.g., a word, such as a password) and the system determines the spoken word b) selecting from a pre-defined vocabulary. Therefore voice recognition provides for the ability to recognize a spoken phrase and not the identity of the speaker.
The terms voice verification and voice authentication are interchangeably used hereinbelow. Techniques of voice verification have been extensively described in U.S. Pat. Nos. 5,502,759; 5,499,288; 5,414,755; 5,365,574; 5,297,194; 5,216,720; 5,142,565; 5,127,043; 5,054,083; 5,023,901; 4,468,204 and 4,100,370, all of which are incorporated by reference as if fully set forth herein. These patents describe numerous methods for voice verification.
Voice authentication seeks to identify the speaker based solely on the spoken utterance. For example, a speaker's presumed identity may be verified using a feature extraction and pattern matching algorithms, wherein pattern matching is performed between features of a digitized incoming voice print and those of previously stored reference samples. Features used for speech processing involve, for example, pitch frequency, power spectrum values, spectrum coefficients and linear predictive coding, see B. S. Atal (1976) Automatic recognition of speakers from their voice. Proc. IEEE, Vol. 64, pp. 460-475, which is incorporated by reference as if fully set forth herein.
Alternative techniques for voice authentication include, but are not limited to, neural network processing, comparison of a voice pattern with a reference set, password verification using selectively adjustable signal thresholds, and simultaneous voice recognition and verification.
State-of-the-art feature classification techniques are described in S. Furui (1991) Speaker dependent-feature extraction, recognition and processing techniques. Speech communications, Vol. 10, pp. 505-520, which is incorporated by reference as if fully set forth herein.
Text-dependent speaker recognition methods rely on analysis of predetermined utterance, whereas text-independent methods do not rely on any specific spoken text. In both case, however, a classifier produces the speaker's representing metrics which is thereafter compared with a preselected threshold. If the speaker's representing metrics falls below the threshold the speaker identity is confirmed and if not, the speaker is declared an impostor.
The relatively low performance of voice verification technology has been one main reason for its cautious entry into the marketplace. The “Equal Error Rate” (EER) is a calculation algorithm which involves two parameters: false acceptance (wrong access grant) and false rejection (allowed access denial), both varying according the degree of secured access required, however, as shown below, exhibit a tradeoff therebetween. State-of-the-art voice verification algorithms (either text-dependent or text-independent) have EER values of about 2%.
By varying the threshold for false rejection errors, false acceptance errors are changing as graphically depicted in FIG. 1 of J. Guavain, L. Lamel and B. Prouts (March, 1995) LIMSI 1995 scientific report, which is incorporated by reference as if fully set forth herein. In this Figure presented are five plots which correlate between false rejection rates (abscissa) and the resulting false acceptance rates for voice verification algorithms characterized by EER values of 9.0%, 8.3%, 5.1%, 4.4% and 3.5%. As mentioned above, there is a tradeoff between false rejection and false acceptance rates, which renders all plots hyperbolic, wherein plots associated with lower EER values fall closer to the axes.
Thus, by setting the system for too low false rejection rate, the rate of false acceptance becomes too high and vice versa.
Various techniques for voice-based security systems are described in U.S. Pat. Nos. 5,265,191; 5,245,694; 4,864,642; 4,865,072; 4,821,027; 4,797,672; 4,590,604; 4,534,056; 4,020,285; 4,013,837; 3,991,271; all of which are incorporated by reference as if fully set forth herein. These patents describe implementation of various voice-security systems for different applications, such as telephone networks, computer networks, cars and elevators.
However, none of these techniques provides the required level of performance, since when a low rate of false rejection is set, the rate of false acceptance becomes unacceptably high and vice versa.
To try and overcome the above mentioned limitation of prior art systems, U.S. Pat. No. 5,913,196 to the present inventors, describes a computerized system which includes at least two voice authentication algorithms. Each of the voice authentication algorithms is different from the others and serves for independently analyzing a voice of the speaker for obtaining an independent positive or negative authentication of the voice by each of the algorithms. If every one of the algorithms provide positive authentication, the speaker is positively identified, whereas, if at least one of the algorithms provides negative authentication, the speaker is negatively identified.
Although the authentication system and method described in U.S. Pat. No. 5,913,196 is considerably more accurate than other prior art voice authentication systems, it still suffers from limitations common to prior art systems, which limitations arise from signal distortion (due to, for example, channel mismatch), user error and random background noise.
There is thus a widely recognized need for, and it would be highly advantageous to have, a voice authentication system and method for authorizing or denying a user access to a secure site, which system and method are devoid of the above limitations.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a system for authorizing a user access to a secure site, the system comprising (a) a memory unit being for storing information including a stored voice print and an identity of each of a plurality of individuals having access to the secured site, the stored voice print of each of the plurality of individuals being generated from
Talmor Alon
Talmor Eli
Talmor Rita
Friedman Mark M.
McFadden Susan
Sentry Com Ltd.
LandOfFree
Voice authentication method and system utilizing same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Voice authentication method and system utilizing same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Voice authentication method and system utilizing same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3050105