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標題: | 座艙語音記錄器之單通道適應性噪音濾除 Single Channel Adaptive Noise Cancellation for Noisy Speech from Cockpit Voice Recorders |
作者: | Chih-Ting Liu 劉致廷 |
指導教授: | 陳永耀 |
關鍵字: | 座艙語音記錄器,單通道噪音濾除,適應性濾波器,主要頻率合成,線性預估誤差濾波器, Cockpit Voice Recorder,Single Channel Noise Cancellation,Adaptive Filter,Principal Frequencies Synthesis,Linear Prediction Error Filter, |
出版年 : | 2007 |
學位: | 碩士 |
摘要: | 為了調查飛航事故之可能肇事原因,我們利用飛航記錄器來協助失事調查。而飛航記錄器一般有兩種形式,一為座艙語音記錄器(Cockpit Voice Recorder, CVR),一為飛航資料記錄器(Flight Data Recorder, FDR)。座艙通話記錄器除了記錄駕駛員的通話內容外還會把非語音的聲音一併記錄起來,例如,螺旋槳噪音、開關撥動聲…等。當螺旋槳噪音的能量遠大於駕駛員語音的能量時,我們很難從其中辨別出駕駛員的語音內容來調查失事原因。因此,噪音濾除可視為我們最首要的任務。傳統的適應性噪音濾除需要兩組感應器來擷取訊號做噪音濾除,但是我們沒有第二組感測器來擷取噪音源訊號。本論文利用適應性濾波器基於主要頻率合成及線性預估誤差濾波器來實現單通道噪音濾除。適應性濾波器基於主要頻率合成主要是用來消除螺旋槳噪音;而線性預估誤差濾波器主要是用來消除語音中的餘值噪音訊號。如此,我們可以清楚辨識駕駛員的語音內容以幫助調查失事原因。 We use a flight recorder to assist the aircraft accident investigation for identifying the probable cause of aircraft accident. There are two forms in a flight recorder, the Flight Data Recorder (FDR) and the Cockpit Voice Recorder (CVR). The CVR effectively acts as a latent signal transducer for both speech and non-speech acoustic information such as propeller noise, switch sound…etc. When the power of the noise from propeller is overwhelmingly greater than the power of the desired pilot’s speech, we cannot identify the pilot’s speech content to investigate the accident cause. A typical technique, adaptive noise cancellation, appears to be the primary task, but it assumes the use of two sensors. In our situation, we do not have the second sensor to pick up the reference signal to achieve noise cancellation. This thesis hence focus on single channel noise cancellation using adaptive filter based on principal frequencies synthesis (PFS) and linear prediction error filter (LPEF). Adaptive filter based on PFS is used to cancel the propeller noise form CVR; LPEF is used to whiten the residual noise in speech. Thus we can identify the pilot’s speech content more easily from the enhanced speech to assist us in the accident investigation. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/24965 |
全文授權: | 未授權 |
顯示於系所單位: | 電機工程學系 |
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ntu-96-1.pdf 目前未授權公開取用 | 1.62 MB | Adobe PDF |
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