Opens in a new tab

AES E-Library

← Back to search

Conference Paper

Objective Speech Intelligibility Measures Based on Speech Transmission Index for Forensic Applications

Authors: Costantini, Giovanni; Paoloni, Andrea; Todisco, Massimiliano

AES Conference: 39th International Conference: Audio Forensics: Practices and Challenges · Paper 8-2 · June 2010

Abstract

In order to decide whether the transposition of the speech originated from a lawful interception, in the written text reflect the views of those who spoke the words or only the views of the transcriber, is required to have an objective method to measure speech intelligibility. Usually, a lawful interception can have two types of distortion: the distortions that affect the speech signal itself (called speech distortion) and the distortions that affect the background noise (called noise distortion). Unfortunately, the forensic expert does not have the original clean signal, therefore, must make its assessment based on the only available signal. This paper addresses the issue by using three different objective approaches, that are the Signal-to-Noise ratio weighted with the curves "A" (S/NA), the Articulation Index (AI) and Speech Transmission Index (STI) to evaluate the signal and a corpus which is measured voice intelligibility. The approaches are tested with three different types of noise and the results were compared with the speech intelligibility scores measured by subjective tests. Measures based on STI have proven to be reliable for predicting the intelligibility in forensic applications.

Details

Published in
AES Conference: 39th International Conference: Audio Forensics: Practices and Challenges
Paper number
8-2
Publication date
June 6, 2010
Session subject
Speech and Forensics - Automated Systems
Affiliation
Fondazione Ugo Bordoni, Rome, Italy; Università Tor Vergata, Rome, Italy; Institute of Acoustics O.M. Corbino, Rome, Italy (See document for exact affiliation information.)
Type
Conference Paper