Digital Signal Processing and System Theory

Talk Vasudev Kandade Rajan

Multi-channel Speech Quality Improvement for Automotive Applications

Date: 15.09.2011, 13:00 h - 14:00 h, Room: Aquarium

Vasudev Kandade Rajan
CAU, Kiel, Germany


Speech inside a car can put into two categories. In the first category, the travelers are talking "locally" to each other, in the second a (phone) call made to/from the car, where the "local" speaker speaks to a "remote" speaker with the help of a hands-free system. Out of the many factors that could potentially affect the quality of conversation in a phone call, the acoustical echo is the most prominent one. An acoustical echo is on in which the remote side speaker hears his/her own voice after a certain delay.

The main topic of the presentation and my thesis is to build a real-time system which can remove these echoes. The system has a parallel and postfilter structure. With such a structure even when the parallel filters has not fully converged, it is still possible to suppress the echoes (also referred to as residual echoes).
The talk will show how we successfully handle the "double talk situation", the most difficult task for an echo canceller. I will also show how a simple adaptive filter needs many subunits to function as desired. The talk will also include a small demonstration of the system in real-time.

Talk Vasudev Kandade Rajan