Caller identification in a secure environment using voice biometrics

Abstract

A method for passive enrollment and identification of a telephone caller to a called telephone number, comprising the steps of audio recording a telephone call; identifying and separating any multiple speakers on the telephone call and specifying a one of the multiple speakers; creating a net speech portion of the telephone call by trimming portions of audio recording from the beginning and end of the audio recording; processing the net speech portion against an existing Biometric Voice Print (BVP) database; creating a new BVP for the at least one of the multiple speakers if no match of the net speech portion against the BVP database is found in the processing step; comparing subsequent calls against the BVP, whether existing or created, to identify the at least one of the multiple speakers; and associating in a cluster all subsequent calls having voice prints matching the BVP.

What is claimed is: 
     
         1 . A method for passive enrollment and identification of a telephone caller in a telephone call to a called telephone number, comprising the steps of:
 a) selecting one of said speakers;   b) designating a net speech portion of speech by said selected speaker by trimming portions of said speech from the beginning and end of said telephone call;   c) creating a biometric voice print of said net speech portion;   d) processing said biometric voice print against an existing biometric voice print database;   e) creating a new biometric voice print for said selected speaker if no match of said biometric voice print against said database is found in said processing step; and   f) iterating said processing step a plurality of times during the remainder of said telephone call to detect changes in identity of said selected speaker.   
     
     
         2 . A method in accordance with  claim 1  comprising the further step of comparing voice prints of callers on subsequent telephone calls against said BVP, whether existing or created, to identify again said selected speaker. 
     
     
         3 . A method in accordance with  claim 1  comprising the further step of audio recording said telephone call including the voice of said speaker prior to said designating step. 
     
     
         4 . A method in accordance with  claim 1  comprising the further step of associating in a cluster all subsequent calls having voice prints matching said BVP. 
     
     
         5 . A method in accordance with  claim 2  comprising the further steps of:
 a) identifying telephone numbers associated with said subsequent calls; and 
 b) clustering all such telephone numbers in association with said called number. 
 
     
     
         6 . A method in accordance with  claim 1  wherein said creating step comprises the steps of:
 a) computing the AIP/AIS of said caller; and 
 b) triggering creation of a BVP only if said AIP/AIS exceeds a predetermined threshold. 
 
     
     
         7 . A method in accordance with  claim 1  wherein said processing step is carried out if said net speech portion is at least seven seconds long. 
     
     
         8 . A method in accordance with  claim 1  wherein said creating step is carried out if said net speech portion is at least 30 seconds long. 
     
     
         9 . A method in accordance with  claim 1  comprising the further steps of:
 a) downloading a plurality of recordings of calls from said caller; 
 b) processing said plurality of recordings to yield a plurality of net speech portions; 
 c) generating a plurality of voice prints from said plurality of net speech portions; and 
 d) creating an enhanced BVP from said new BVP and said plurality of voice prints. 
 
     
     
         10 . A method in accordance with  claim 1  wherein said caller is selected from the group consisting of an inmate within a secure facility and a civilian outside said secure facility. 
     
     
         11 . A method in accordance with  claim 1  wherein both the caller and the person being called can be identified from a single recording comprising speech of both persons. 
     
     
         12 . A method in accordance with  claim 1  comprising the further steps of:
 a) determining whether the caller is a person of interest; 
 b) alerting the facility that a person of interest is leaving a voice mail; 
 c) identifying instances of said caller using multiple telephone numbers to leave voice mail messages for the same or multiple inmates. 
 
     
     
         13 . A method in accordance with  claim 1 , comprising the further steps of:
 a) associating a Billing Telephone Number with said telephone caller;   b) preprocessing said call to normalize volume, suppress silence, and reduce ambient noise;   c) isolating said caller's voice from any other voices on said telephone call;   d) trimming the beginning and end of said call;   e) extracting at least seven seconds of net speech of said caller;   f) creating a voice print of said net speech;   g) comparing said voice print of said caller against the BVP database.   
     
     
         14 . A method in accordance with  claim 13 , comprising the further steps of:
 a) establishing a test window length within said telephone call;   b) continuously analyzing speaker voice input during said call;   c) generating a first test voice identification score at the conclusion of said first test window;   d) starting a second test window before the end of said first test window such that said second test window overlaps a portion of said first test window;   e) starting one or more additional test windows wherein each of said additional test windows overlaps a portion of the immediately preceding test window.   
     
     
         15 . A method in accordance with  claim 14  wherein each of said test windows is equal in length. 
     
     
         16 . A method in accordance with  claim 13  wherein said first test window is between 7 and 30 seconds in length, and wherein said second test window begins between 3.5 and 15 seconds into said call. 
     
     
         17 . A method in accordance with  claim 13  comprising the further step of continuing to monitor the identity of said caller throughout said call. 
     
     
         18 . A method in accordance with  claim 13  comprising the further step of identifying all existing voice prints matching said incoming caller voice prints.