A new software for forensic voice comparison: IMPAVIDO

IMPAVIDO (Integrated Methods for Parametric Voice Identification) is a new tool for forensic voice comparison.

IMPAVIDO provides the user with an operating environment for performing forensic speaker recognition activities by comparing the spectral-acoustic characteristics of the recorded voice of one or more subjects.

IMPAVIDO's primary users are professionals in the investigative and judicial sectors: experts, technical consultants, and judicial police personnel.

IMPAVIDO implements two semi-automatic, acoustic-phonetic methodologies, inspired by those most widely used in Italy: a) the IDEM/SPREAD (IDEntification Method), developed by the Ugo Bordoni Foundation in Rome, and traditionally used by the Carabinieri Corps, and b) SMART (Statistical Methods Applied to the Recognition of the Talker), traditionally used by the Italian Police.

The innovative feature of the IMPAVIDO software compared to the two aforementioned methodologies is that it emulates them in the same software environment, offering the user an integrated system in order to provide a broader view of the characterization of the acoustic parameters being compared.

IMPAVIDO also includes some corrections to the IDEM methodology, as well as the implementation of metrics for assessing the accuracy of recognition operations.

Finally, unlike IDEM and in line with SMART, IMPAVIDO potentially allows for work on the seven Italian vowels (/i, e, ɛ, a, ɔ, o, u/).

IMPAVIDO is based on the Bayesian method and therefore on the Likelihood Ratio, now accepted and strongly recommended by the international forensic scientific community, in line with ENFSI recommendations.

This approach aims to provide evidence in court in terms of statistical probability to support the hypothesis that two compared voices belong to the same individual versus the hypothesis that they belong to different individuals, overcoming the old "identified/unidentified" assessments which, in principle, are not the responsibility of the expert, but of the judge, based on all the evidence emerging during the trial.