Research On Hilbert-Huang Transform And Its Application In Noisy Speech Signal Processing

With the development of modern science and technology, as a multidisciplinary and comprehensive subject, digital speech signal processing has become a hot research area nowadays. Due to the non-linear characteristics of speech signals, the performance of traditional speech processing techniques based on linear methods cannot be improved any more. The lately developing and ameliorating non-linear, non-stationary signal processing theories have brought new direction for speech signal processing.In general, speech signals are often corrupted acoustically by ambient noise. The noise degrades both the quality and the intelligibility of the speech signals; even make the speech processing system does not work well. So speech enhancement technologies are strongly desired to solve the problem. The objective of speech enhancement and speech detection is to reduce background noise, to improve the quality of voice communication, to increase the intelligibility and to ensure the reliability of the speech processing systems. Furthermore, speech enhancement can greatly improve the performance of many speech encoding and recognition system in the noisy environment. Speech enhancement technologies are a very important part of digital speech signal processing, and it is extensively used in wireless telephone, conference call, scene record, military wiretap and other fields.The new time-frequency analysis method, Hilbert-Huang transform based on EMD, was taken as a scientific breakthrough to Fourier analysis which base is linear and stationary. This work was supported by national science foundation project 'Speech stream detection in adverse acoustics environment based on Hilbert—Huang transform'.Based on the research of Hilbert—Huang transform, the main study contents are as follows:...