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    Please use this identifier to cite or link to this item: http://asiair.asia.edu.tw/ir/handle/310904400/26292


    Title: 使用互補型雜訊移除演算法及聲譜濾波法於語音增強之研究
    Authors: 陸清達
    Contributors: 資訊學院;資訊傳播學系
    Keywords: 語音增強;頻譜刪減;音樂型殘留雜訊;中值濾波;後處理;脈衝雜訊移除;Speech enhancement;spectral subtraction;musical residual noise;median filter;post processing;impulse noise denoising
    Date: 2011
    Issue Date: 2013-07-18 15:56:59 (UTC+8)
    Abstract: 有許多的語音增強處理系統已經成功地被提出來從事改善受到各種雜訊干擾的語 音信號,但是大部分的方法,都面臨殘留雜訊過多與語音失真太嚴重的問題。我們經過 仔細的研究發現:使用聽覺遮蔽閾值調適的方法處理受干擾語音信號,可以藉由保留人 耳聽不見的殘留雜訊,維持較多的受干擾語音信號,達到降低語音失真的目的;可是受 到背景雜訊估計誤差的影響,造成增強後的語音信號中的音樂型殘留雜訊效應依然很明 顯,聽起也非常吵雜,其主因就是具有較大音強的殘留雜訊頻譜,隨機地分佈在相鄰次 頻帶與相鄰音框中所致;要如何降低音樂型殘留雜訊的效應,依然是一項迫切需要解決 的問題。有許多殘留雜訊抑制的後處理演算法,在抑制殘留雜訊頻譜的過程中,會造成 嚴重的語音失真,或者產生回音現象,使得後處理的效果不盡理想。所以本研究計畫嘗 試透過語音增強及後處理方式,有效抑制殘留雜訊與保留語音信號。首先,我們將設計 精良的互補型雜訊抑制演算法,在語音信號失真最小的情形下,能有效抑制受干擾語音 信號中的背景雜訊,並且可以提升音樂型殘留雜訊的鑑別度;接著施以疊代式二維聲譜 濾波的後處理方式,大幅的抑制音樂型殘留雜訊頻譜,提升增強後的語音信號品質。

    Many speech enhancement systems have been proposed to enhance a speech signal corrupted by various kinds of noise. However, most of them suffer from a quantity of residual noise containments and serious speech distortion. After careful study on the research topic of speech enhancement, we find that a speech enhancement algorithm adapted by the auditory masking properties of the human ear performs better than the other state-of-the-art methods. It is attributed to the fact that residual noise with small magnitude is inaudible to the human ear. Preserving it does not cause annoying effect, but brings the benefit of reducing speech distortion in the enhanced speech. However, the annoying musical residual noise still exists and is apparent in the spectrogram. The major reason is the incorrect estimation on the noise level, yielding musical residual tones with strong energy to randomly appear over neighbor subbands and in successive frames. Thus, how to reduce the effect of musical residual is an import task for speech enhancement. Many residual noise reduction algorithms produce serious speech distortion and echo effect, resulting in the quality of enhanced speech to be deteriorated. In this project, we aim at improving the performances of the reduction of residual noise and of the preservation of speech quality by speech enhancement and post-processing techniques. Firstly, we will design an improved version of complementary denoising algorithm to efficiently remove the background noise, while the speech distortion is kept at a low level and the residual noise should be apparent for detection. In turn, an iterative-two-dimensional spectrogram filtering technique will be developed for significantly reducing the spectra of musical residual noise. Accordingly, the quality of the enhanced speech is improved.
    Appears in Collections:[資訊傳播學系] 科技部研究計畫

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