ISCA Tutorial and Research Workshop on Statistical and Perceptual Audio Processing

ICC Jeju, Korea
October 3, 2004

Harmonicity Based Blind Dereverberation with Time Warping

Tomohiro Nakatani, Keisuke Kinoshita, Masato Miyoshi, Parham S. Zolfaghari

NTT Communication Science Laboratories, NTT Corporation, Seika-cho, Soraku-gun, Kyoto, Japan

Speech dereverberation is desirable in applications such as robust automatic speech recognition (ASR) in the real world. Although a number of dereverberation methods have been exploited, dereverberation is still a challenging problem especially when using a single microphone. To overcome this problem, a harmonicity based dereverberation method (HERB) has recently been proposed. HERB can blindly estimate the inverse filter of a room impulse response based on harmonicity of speech signals and dereverberate the signals. However, HERB uses an imprecise assumption that hinders the dereverberation performance, that is, the fundamental frequency (F0) of a speech signal is assumed to be constant within a short time frame when extracting the features of harmonic components. In this paper, we introduce time warping analysis into HERB to remove this bottleneck. Time warping analysis expands and contracts the time axis of a signal in order to make the F0 of the signal constant, and makes it possible to estimate harmonic components precisely even when their frequencies change rapidly. We show that time warping analysis can effectively improve the dereverberation effect of HERB when the reverberation time is longer than 0.1 sec.

Full Paper
Acoustic Examples:   Reverberant   Dereverberated  

Bibliographic reference.  Nakatani, Tomohiro / Kinoshita, Keisuke / Miyoshi, Masato / Zolfaghari, Parham S. (2004): "Harmonicity based blind dereverberation with time warping", In SAPA-2004, paper 53.