Digital Signal Processing Reference
In-Depth Information
Chapter 6
USE OF MULTIPLE SPEECH RECOGNITION
UNITS IN AN IN-CAR ASSISTANCE SYSTEM
1
Alessio Brutti
1
, Paolo Coletti
1
, Luca Cristoforetti
1
, Petra Geutner
2
,
Alessandro Giacomini
1
, Mirko Maistrello
1
, Marco Matassoni
1
, Maurizio
Omologo
1
, Frank Steffens
2
, Piergiorgio Svaizer
1
1
ITC-irst (Centro per la Ricerca Scientifica e Tecnologica), I-38050 Povo - Trent, Italy;
2
Robert Bosch GmbH, Corporate Research and Development, P.O. Box 10 60 50, Stuttgart
Germany.
Email: brutti@itc.it
Abstract:
This chapter presents an advanced dialogue system based on in-car hands-free
voice interaction, conceived for obtaining driving assistance and for accessing
tourist information while driving. Part of the related activities aimed at
developing this “Virtual Intelligent Codriver” are being conducted under the
European VICO project. The architecture of the dialogue system is here
presented, with a description of its main modules: Front-end Speech Processing,
Recognition Engine, Natural Language Understanding, Dialogue Manager and
Car Wide Web. The use of a set of HMM recognizers, running in parallel, is
being investigated within this project in order to ensure low complexity,
modularity, fast response, and to allow a real-time reconfiguration of the
language models and grammars according to the dialogue context. A corpus of
spontaneous speech interactions was collected at ITC-irst using the Wizard-of-
Oz method in a real driving situation. Multiple recognition units specialized on
geographical subdomains and simpler language models were experimented
using the resulting corpus. This investigation shows that, in presence of large
lists of names (e.g. cities, streets, hotels), the choice of the output with
maximum likelihood among the active units, although a simple approach,
provides better results than the use of a single comprehensive language model.
Keywords:
Automatic speech recognition,
in-car dialogue system, driving assistance,
language models.
1
This work was partially funded by the Commission of the EC, Information Society Technologies (IST), 2000-25426,
under VICO. Partners of the VICO project are Robert Bosch GmbH (D), DaimlerChrysler AG (D), ITC-irst (I) and
Phonetic Topographies NV (B).
