This paper proposes an efficient compensation method using a first-order approximation of time axis scaling for the variations of the room acoustic transfer function. The time axis scaling model is based on the fact that the change of the sound velocity due to the change of room temperature is a dominant factor for the variations of room impulse response affected by environmental conditions. In this paper, the effectiveness of the compensation method is evaluated using room impulse responses measured in the real environment. As the results, it is clarified that the variations of room impulse response can be modeled by the first-order approximated time axis scaling when the successive re-estimation is performed every small change of temperature. Furthermore, it is shown that the compensation method applied to an inverse filtering based dereverberation approach improves the intelligibility and speech recognition rates dramatically.
['Michiaki Omura', 'Motohiko Yada', 'Hiroshi Saruwatari', 'Shoji Kajita', 'Kazuya Takeda', 'Fumitada Itakura']
Compensating of room acoustic transfer functions affected by change of room temperature