This paper discusses signal processing methods for speech extraction in use with voice communication applications such as personal digital assistants (PDA:s), mobile telephone terminals and personal computers. The user will be distant from the device and thus the speech signal entering the device will be subject to reverberation as well as disturbed by background noise. The proposed structure consists of a microphone array which allows for techniques of directional processing. Thus it will be able to enhance a desired speech source and suppress other speech sources in the background. Three different optimal beamforming methods are considered in a real world car hands-free environment; an optimal near-field array gain optimization procedure, a theoretical diffuse noise field model for a point source and a least squares solution.

Arbetet beskriver problemformuleringen av spatiell talf;rb'ttring av bredbandiga signaler i närfältet. En ny praktisk implementering presenteras och utvärderas.