NCJ Number
66275
Journal
Kriminalistik Volume: 31 Dated: (1977) Pages: 529-540
Date Published
1978
Length
11 pages
Annotation
THE AUROS AUTOMATIC SPEAKER RECOGNITION SYSTEM WAS TESTED FOR RELIABILITY IN THIS EXPERIMENT BY THE WEST GERMAN MINISTRY OF RESEARCH AND TECHNOLOGY.
Abstract
AUTOMATIC VOICE RECOGNITION SYSTEMS THAT CAN BY CONNECTED TO THE PUBLIC TELEPHONE SYSTEM SERVE TWO FUNCTIONS: THEY VERIFY THE SPEAKER'S PROFESSED IDENTITY BY COMPARING THE TELEPHONE VOICE TO ALREADY STORED VOICE DATA OF THAT PERSON, AND THEY ATTEMPT TO IDENTIFY THE SPEAKER BY SCANNING THE DATA BASE FOR AN IDENTICAL VOICE. COMPUTERIZED VOICE RECOGNITION FACES TWO BASIC PROBLEMS: THE VARIATIONS OF THE VOICE PRINTS OF AN INDIVIDUAL SPEAKER AND THE HUGE AMOUNT OF DATA THAT MUST BE DECODED TO IDENTIFY A VOICE. THE AUROS (AUTOMATIC RECOGNITION OF SPEAKERS) SYSTEM TESTED IN THE PHILIPS LABORATORY IS ABLE TO IDENTIFY IN EACH CASE THE MOST EFFICIENT METHOD FOR IDENTIFICATION (E.G., THE FOURIER TRANSFORMATION, THE WALSH-HADAMARD TRANSFORMATION, OR INVERSE FILTERING). THE AUTOMATIC IDENTIFICATION PROCESS INCLUDES PRELIMINARY DATA TREATMENT, ANALYSIS OF THE SPEECH SEGMENT, CLASSIFICATION OF THE VOICE, AND CONCLUDING VERIFICATION. THE RELIABILITY RESEARCH ON AUROS INSPECTED 5,000 VOICE SAMPLES OF KNOWN SPEAKERS IN ACCORDANCE WITH THE MOST EFFICIENT IDENTIFICATION METHOD. THE SYSTEM WAS FORCED TO MAKE AN IDENTIFICATION, AND COMPUTER REJECTIONS WERE NOT ACCEPTED. FOR THE 2,500 CONTEXT DEPENDENT AND THE 2,500 CONTEXT INDEPENDENT SAMPLES, THE RECOGNITION RATE WAS AS HIGH AS 99.5 PERCENT. DURING THE VOICE VERIFICATION TEST, THE SYSTEM HAD TO STEER A MIDDLE COURSE TO AVOID TWO OPPOSING SOURCES OF ERROR: THE ERRONEOUS ACCEPTANCE OF A NONIDENTICAL VOICE AND THE ERRONEOUS REJECTION OF AN IDENTICAL VOICE. THE ERROR RATES IN BOTH DIRECTIONS WERE FOUND TO BE 1 PERCENT. THE PROBLEMS OF DELIBERATE VOICE DISTORTION AND OF DISTORTION THROUGH THE TELEPHONE SYSTEM ARE AS YET UNRESOLVED AND AS OF 1977 FORM THE SUBJECT OF A MAJOR RESEARCH PROJECT SPONSORED BY THE WEST GERMAN BUREAU OF CRIMINAL INVESTIGATION. THE ARTICLE CONTAINS NUMEROUS VOICE GRAPHS, MATHEMATICAL FORMULAS, AND A SHORT BIBLIOGRAPHY. --IN GERMAN. (SAJ)