Noisy speech enhancement using discrete cosine transform

This paper illustrates the advantages of using the Discrete Cosine Transform (DCT) as compared to the standard Discrete Fourier Transform (DFT) for the purpose of removing noise embedded in a speech signal. The derivation of the Minimum Mean Square Error (MMSE) ®lter based on the statistical modelling of the DCT coecients is shown. Also shown is the derivation of an over-attenuation factor based on the fact that speech energy is not always present in the noisy signal at all times or in all coecients. This over-attenuation factor is useful in suppressing any musical residual noise which may be present. The proposed methods are evaluated against the noise reduction ®lter proposed by Y. Ephraim and D. Malah (1984), using both Gaussian distributed white noise as well as recorded fan noise, with favourable results. Ó 1998 Elsevier Science B.V. All rights reserved. ReÂsume Cet article illustre les avantages apportes par l'utilisation de la Transformation Cosinus Discrete (D...

• Type: Journal
• Year: 1998
• Where: SPEECH
• Authors: Ing Yann Soon, Soo Ngee Koh, Chai Kiat Yeo
• Keywords: Du Bruit, La Parole, Over-attenuation Factor, SPEECH 1998