In noise suppression systems for automotive applications, the use of adaptive beamformers has proven to be of great potential. Nevertheless, in diffuse noise fields the amount of noise attenuation is rather limited and depends on the number of microphones. In order to enhance the signal-to-noise ratio further, additional classical noise suppression schemes, like spectral subtraction, are often applied. Unfortunately, these schemes tend either to introduce speech distortions or to leave a large amount of residual noise. We describe a method of extracting additional spatial information from a conventional beamformer in a generalized sidelobe structure. This spatial information can be utilized, e.g., to control parameters, like overestimation or spectral floor, of classical noise suppression schemes in a frequency selective manner or to compute a simple attenuation factor for suppressing nonstationary noise. An outlook is given on further usage of the spatial information in other algorithmic parts of a hands-free telephone or a speech recognition system.
['M. Fuchs', 'Tim Haulick', 'Gerhard Schmidt']
Noise suppression for automotive applications based on directional information