Acoustic signal analysis for forensic applications
Durand R. Begault, Christopher Peltier · The Journal of the Acoustical Society of America · 2006
Acoustical analysis of audio signals is important in many legal contexts for determining the authenticity, originality, and continuity of recorded media; determining the circumstances of events in question that may have been recorded; for determining the audibility of signals; and for identification or elimination of talkers as a match to an unknown exemplar. Recorded media are analyzed in forensic applications using both familiar techniques (waveform and spectral analyses) and more novel methods (e.g., ferro fluid development of media; specialized tape heads with nonstandard reproduction characteristics; crystal microscopy; detection and matching to power grid frequencies). Audibility analyses frequently require careful reconstructive field measurements and criteria in excess of normally accepted standards. Voice identification-elimination protocols must account for examiner bias and exemplar quality and can be described using a receiver operator curve (ROC) model. This presentation gives an overview of these techniques and their comparative advantages for specific forensic applications.