Voice Stress Analysis Technology
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The author(s) shown below used Federal funds provided by the U.S. Department of Justice and prepared the following final report: Document Title: Investigation and Evaluation of Voice Stress Analysis Technology Author(s): Darren Haddad, Sharon Walter, Roy Ratley, Megan Smith Document No.: 193832 Date Received: March 20, 2002 Award Number: 98-LB-VX-A013 This report has not been published by the U.S. Department of Justice. To provide better customer service, NCJRS has made this Federally- funded grant final report available electronically in addition to traditional paper copies. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice. Investigation and Evaluation of Voice Stress Analysis Technology Final Report February 13,2002 Darren Haddad Roy Ratley Sharon Walter Megan Smith AFRUIFEC ACS Defense Rome Research Site Rome, NY This project is supported under Interagency Agreement 98-LB-R-013 from the Office of Justice Programs, National Institute of Justice, Department of Justice. Points of view in this document are those of the author(s) and do not necessarily represent the official position of the U.S. Department of Justice. Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. Table of Contents 1.0 EXECUTIVE SUMMARY ......................................................... 1 2.0EFFORTOBJECTIVE ............................................................ 1 3.0INTRODUCTION ................................................................ 1 4.0HISTORYOFVSATECHNOLOGY ................................................. 2 5.0 AVAILABLE VSA SYSTEMS ...................................................... 5 5.1 PSYCHOLOGICAL STRESS EVALUATOR (PSE) ........................................... 5 5.2LANTERN ...................................................................... 5 5.3VERlCATOR ..................................................................... 5 5.4 COMPUTERIZED VOICE STRESS ANALYZER (CVSA) ..................................... 6 5.5VSAMARKlOOO ................................................................ 6 5.6VSA-15 ....................................................................... 6 5.7XANDlELECTRONICS ............................................................. 6 5.8TVSA3 ........................................................................ 7 6.0 METHODS OF VOICE STRESS ANALYSIS AND CLASSIFICATIONS ...................7 7.0TESTING ....................................................................... 8 7.1TESTOBJECTIVE ................................................................. 8 7.2 SCOPE/APPROACH............ ........ ............8 7.3 TEST AND ANALYSIS PROCEDURES . ........................ 9 7.4 SYSTEMS TESTED ............... ........................ 9 7.5 TECHNICAL TESTING ............. .................... 7.5.I Artijicial Signal Test (Test I) .................................................. 9 7.5.1.I Objective (Tcst I) .................... 7.5.1.2Test1 Set-Up ....................... 7.5.1.3Vericator ................................ ......... 10 7.5.1.4Diogenes Lantern .................................................... 7.5.2.2Scope ............................. 1.5.2.3Test ...... ........................................... 13 7.5.2.5SumrnaryTest2 ................................................................ 15 7.5.3Objective (Test 3) ...................... 7.5.3.1 Data Evaluation (Test 3) ................................... 7.5.3.2Data collection and Down Sampling .... 7.5.3.3Segmentation ................ .. ................................. 16 7.5.3.4Testing ........................... .............................................. 16 7.6FIELDTESTING ............................................................... 16 8-OCONCLUSION .................................................................. 19 9.0 SUGGESTED FOLLOW ON ......................................................19 1 Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. REFERENCES ...................... .............. ...................... 20 AppendixA ...................................... ................... 21 AppendixB .................................................................... 22 AppendixC .................................................................... 25 ii Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. List of Figures FIGURE1: FM RECORDER TEST SIGNALS @ 80 HZ & I60 HZ .................................. 10 FIGURE 2: WAVERFORMS TO THE DIOGENES LANTERN SYSTEM ................................ 12 FIGURE 3: TEST CONFIGURATION FOR SOURCE CONSISTENCY TESTS ............................ 13 FIGURE 4: WAVEFORM CHANGES USING THE CASSETTE RECORDER WITHOUT THE AGC SET ........... 15 iii Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. List of Tables TABLE1:COSTCOMPARISONS MADE BY A VSA VENDOR . 2 iv Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. Preface Relationship between the Air Force (AF) and the National Institute of Justice (NIJ): The National Law Enforcement and Corrections Technology Center -Northeast Region (NLECTC-NE) was established at the Air Force Research Laboratory - Information Directorate (AFRLAF) (formerly Rome Laboratory) in Rome, NY in 1996. The mission of the NLECTC-NE is to work with government, industry, and academia to identify, evaluate, demonstrate, develop and assess technology applications for law enforcement and corrections. AFRL/IF sponsors research and development in information and hsion, communications, collaborative environment and modeling and simulation, defensive information warfare and intelligent information systems technologies. This partnership allows the NLECTC- NE to draw upon the engineers of AFRL, to help assess the adaptation and development of products and technologies designed for the military with transfer to law enforcement, corrections, and other criminal justice applications. Voice stress analysis technology vendors claim the ability to detect stress, possibly indicating deception, in voice communications. The systems are advertised as being cheaper, easier to use, less invasive in use, and less constrained in their operation than polygraph technology. NIJ is funding the evaluation of the scientific value and utility of existing, commercial voice stress analysis technology for law enforcement requirements through NLECTC-NE. By utilizing the unique partnership with AFRL-IF, a thorough literature search provided insight into the history of the development of voice stress analysis, and information on previous evaluation efforts. AFFU-IF was then able to collect a variety of law enforcement audiohideo data that would be utilized to test the performance of Air Force algorithms developed within the AFRL Information directorate. This report will touch on two of these systems that have been evaluated and tested. V Points of view or opinions stated in this report are those of the authors and do not necessarily represent the official positions or policies of the United States Department of Justice. 1.01 EXECUTIVE SUMMARY Voice Stress Analysis (VSA) systems are marketed as computer-based systems capable of measuring stress in a person's voice as an indicator of deception. They are advertised as being less expensive, easier to use, less invasive in use, and less constrained in their operation than polygraph technology. Law enforcement officials have inquired about this technology. As a result, the National Institute of Justice (NIJ) has petitioned the Air Force Research Laboratory (AFRL/IFE) for assistance in evaluating voice stress analysis technology. This evaluation is broken down in three phases. In the first phase, Dr. John H.L. Hansen, from the University of Colorado, investigated the feasibility of detecting stress from speech. He reported on the methods, analysis, and classification of voice stress contained in the appendix of this report. The second and third phase of this study investigated the reliability of commercial VSA units, from a theoretical point of view and from an application (i.e. law enforcement) point of view. 1.02 EFFORT OBJECTIVE The Objective ofthis effort is to determine the effectiveness of commercially available voice stress analyzers (VSA) to detect "stress" in the voice of a talker. The use of 'lstressed speech" for this effort is defined as speech that exhibits a change in characteristics caused by mental stress such as anxiety and/or fear. Of particular interest is the detection of stressed speech (change) caused by an act of deception under law enforcement interview questioning or military interrogation. 1.03 1.04 INTRODUCTION Police departments everywhere are bombarded with offers of advanced technologies by commercial enterprises that promise to reduce their officers' workload, improve law enforcement effectiveness, and/or save lives. With increasingly limited budgets, police