An Error Concealment Decoding Method for Recognizing Speech with Missing Frames in Distributed Speech Recognition

• Main Authors: CHIA HAO CHANG, 張家豪
• Other Authors: 簡福榮
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/epx2ez

碩士 === 國立臺北科技大學 === 電機工程系研究所 === 102 === Nowadays it is very common to include automatic speech recognition (ASR) as a core component in the interface of mobile devices. In the client-server distributed speech recognition (DSR) system architecture, speech features are extracted and quantized at the user’s end (client end) and sent to a remote recognition server end for recognition. The transmission of speech feature data across networks between the two ends brings in problems of transmission errors. Speech features suffering from frame loss will be inevitable in the application of DSR over error prone channels, where the packets may be lost or discarded due to corruptions or delay. In this thesis, in order to reduce the performance degradation because of frame missing, an error concealment decoding method based on the most reliable reduced frame rate data and adapted hidden Markov model (HMM) is proposed (RFR-MA). The performance of the proposed method is compared to a baseline system, in which linearly interpolated FFR data sequence is used for back-end decoding (FFR-INT). Experimental results show that a DSR system using the RFR-MA method can achieve the same level of accuracy as the FFR-INT method and significantly lessens the computation time.