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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/35395
標題: | 語音加強的雜訊消除技術 Noise Reduction Algorithms for Speech Enhancement |
作者: | Chung-Han Huang 黃重翰 |
指導教授: | 貝蘇章 |
關鍵字: | 語音訊號,Wiener 濾波器,Minimum Statistical雜訊估計,雜訊消除,訊號失真,composite wiener filter, noise reduction,speech distortion,MMSE,wiener filter,noise estimation, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 隨著語音訊號應用越來越廣泛,語音增強上的雜訊消除演算法種類變化也越來越多。但是隨著雜訊消除或壓抑的程度越大,所伴隨的訊號失真也越來越大。訊號失真的狀況深深影響後續的許多應用。例如:語音辨識。本論文研究研究改良Wiener濾波器,使其變成一種可以依據不同雜訊比以少許的雜訊壓抑換回多量的訊號失真,試圖在雜訊消除和訊號失真上取得一個較好的平衡。此外本論文亦提出新的改良概念在Minimum Statistical雜訊估計演算法,用遮罩長度變化來得到較好的雜訊估計,以降低高估雜訊消除到所需訊號的現象。以外,我們將所改良的技術和原本的Wiener濾波器用雜訊消除因子和訊號失真因子在不同的雜訊環境下(例:白雜訊、人群嘈雜聲、非洲世足賽烏烏茲拉樂器聲)做比較,以顯示其改良技術有明顯較好的結果。最後,用不同的判斷方法來使用composite wiener filter使其可以有更好的效果在減少訊號失真並維持一定程度的雜訊壓抑。 When clean speech affected by various types of noise, there are many methods to reduce noise. Companying more noise we reduce, more speech distortions the enhanced signals produce. Although wiener filter makes mean square error minimum(MMSE), it also has highly speech distortions. The thesis improves wiener filter to become a tradeoff filter and implements adaptive tradeoff parameter to let it have different degree of suppression in different SNR. We also improve the wiener filter with different gain function in order to make a balance between noise reduction and speech distortion, and it saves some information of clean speech. Besides, a new noise estimation method originated from minimum statistical estimation is proposed. All of the improvement methods will reduce distortion of speech and maintain a certain degree of noise reduction. At last we compare result of the improved algorithms with conventional wiener filter in white noise, babble noise and Vuvuzela noise based on speech distortion measure and noise reduction measure. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/35395 |
全文授權: | 有償授權 |
顯示於系所單位: | 電信工程學研究所 |
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