Forensic Speaker Identification

A voice is much more than just a string of words. Voices, unlike fingerprints, are inherently complex. They signal a great deal of information in addition to the intended message: the speakers' sex, for example, or their emotional state, or age. Although evidence from DNA analysis grabs the headlines, DNA can't talk. It can't be recorded planning,

A reference for professionals who work with recorded evidence, covering areas such authentication of speech recordings, voice stress analysis, and speaker identification. It covers the basic sciences behind voice identification. It also covers what the reader needs to know about coordinating 'ear witness' lineups.

A voice is much more than just a string of words. Voices, unlike fingerprints, are inherently complex. They signal a great deal of information in addition to the intended message: the speakers' sex, for example, or their emotional state, or age. Although evidence from DNA analysis grabs the headlines, DNA can't talk. It can't be recorded planning, carrying-out or confessing to a crime. It can't be so apparently directly incriminating. Perhaps it is these features that contribute to the interest and importance of Forensic Speaker Identification (FSI)

Forensic Speaker Recognition: Law Enforcement and Counter-Terrorism is an anthology of the research findings of 35 speaker recognition experts from around the world. The volume provides a multidimensional view of the complex science involved in determining whether a suspect’s voice truly matches forensic speech samples, collected by law enforcement and counter-terrorism agencies, that are associated with the commission of a terrorist act or other crimes. While addressing such topics as the challenges of forensic case work, handling speech signal degradation, analyzing features of speaker recognition to optimize voice verification system performance, and designing voice applications that meet the practical needs of law enforcement and counter-terrorism agencies, this material all sounds a common theme: how the rigors of forensic utility are demanding new levels of excellence in all aspects of speaker recognition. The contributors are among the most eminent scientists in speech engineering and signal processing; and their work represents such diverse countries as Switzerland, Sweden, Italy, France, Japan, India and the United States. Forensic Speaker Recognition is a useful book for forensic speech scientists, speech signal processing experts, speech system developers, criminal prosecutors and counter-terrorism intelligence officers and agents.

Almut Braun carried out forensic phonetic speaker identification experiments (voice lineups) with 306 lay listeners. Blind listeners significantly outperformed sighted listeners when the speech recordings were presented in studio quality. For recordings in mobile phone quality or of whispering voices, blind and sighted listeners achieved similar results. The data can be used as reference material for real cases with blind earwitnesses. Furthermore, it is discussed whether blind individuals are particularly suitable to work as forensic audio analysts for law enforcement agencies.

There are many reasons for writing a book; this one was conceived and devel oped mainly for two. First, a new area has emerged from within the forensic sciences-that of forensic phonetics. As with all new specialties, it is necessary to define it, identify its boundaries, justify its importance and compile a list of the elements it encompasses. This book attempts to outline these several rela tionships. Second, over the past decade I have become fascinated with forensics in general and the rapidly expanded subarea of forensic phonetics in particular. Admittedly, the latter field is one that is not as yet sufficiently appreciated-and much more needs to be known about its nature and extent. Yet, I have found it to be a most enjoyable area of study and my attempts to describe its domains were quite informative. It was especially interesting to struggle with the interfaces between forensic phonetics and related fields, and discover how they overlap. Only a few comments will be made about the book's contents here in the preface. For one thing, they are described in some detail in the first chapter.

This volume and its companion volume LNAI 4441 constitute a state-of-the-art survey in the field of speaker classification. Together they address such intriguing issues as how speaker characteristics are manifested in voice and speaking behavior. The nineteen contributions in this volume are organized into topical sections covering fundamentals, characteristics, applications, methods, and evaluation.