Abstract EN:

The amount of services offered by the last generation mobile phones has significantly increased compared to previous generations. Nowadays, phones offer new kinds of facilitiessuch as organizers, phone books, e-mail/fax, and games. At the same time, the size of mobile phones has steadily reduced. Both these observations raise an important question: ?How can we use the full facilities of a mobile phone without a large keyboard??. Voice based human-to-computer interfaces supply a friendly solution to this problem but require an embedded speech recognizer. Over the last decade, the performance of Automatic Speech Recognition (ASR) systems has improved and nowadays facilites the implementation of vocal human-to-computer interfaces. Moreover, even if scientific progress could be noticed, the potential gain (in performance) remains limited by computing resources: a relatively modern computer with a lot of memory is generally required. The main problem to embed ASR in a mobile phone is the low level of resources available in this context which classically consists of a 50/100 MHz processor, a 50/100 MHz DSP, and less than 100KB of memory. This thesis focuses on embedded speech recognition in the context of limited resources