Sixth European Conference on Speech Communication and Technology

Budapest, Hungary
September 5-9, 1999

Spectral Subtraction with Adaptive Averaging of the Gain Function

Harald Gustafsson, Sven Nordholm, Ingvar Claesson

Department of Telecommunications and Signal Processing University of Karlskrona/Ronneby, Ronneby, Sweden

The handsfree mode is convenient when using a mobile phone in a vehicle. This mode brings the microphone away from the talkerís mouth. As a consequence the speech signal picked up has low Signal to Noise Ratio. Thus, to improve the SNR a noise reduction method is employed. The proposed method is an improvement of the well-known spectral subtraction method which uses one SNR-depen-dent gain function to suppress the noise. The proposed method reduces the residual noise artifacts by using an adaptive averaging of the gain function. The adaptation is controlled by a spectral discrepancy measure, which is obtained by comparing the averaged noise spectrum and the current input signal spectrum. Experiments show a noise reduction of 10 dB with good noise quality and sig-nificantly low residual noise distortion. Sound results are presented at

Full Paper (PDF)   Gnu-Zipped Postscript

Acoustic Example #1 [IN]
Acoustic Example #2 [OUT]

Bibliographic reference.  Gustafsson, Harald / Nordholm, Sven / Claesson, Ingvar (1999): "Spectral subtraction with adaptive averaging of the gain function", In EUROSPEECH'99, 2599-2602.