K-L变换语音波形编码算法研究

Speech waveform encoding algorithm research based on K-L transform

为了有效改善解码语音的质量,提出了一种K-L变换语音波形编码算法。由语音帧构造协方差矩阵,并对其进行特征值分解,得到特征值及其对应的特征向量,由特征向量构造正交矩阵;用正交矩阵对语音帧作正交变换得到变换系数向量;选取适当特征值对应的特征向量构造重构矩阵;用重构矩阵对变换系数向量作逆变换得到增强后的语音信号;对增强后的语音抽取并传输至解码端;通过插值技术重构语音信号。在不同信噪比下对不同语音样本进行仿真实验,并同离散余弦变换编码比较,实验表明,该算法不仅数据压缩率高、解码语音清晰和自然,而且同时实现语音良好的自适应增强。

In order to effectively improve the quality of the decoded speech, a kind of speech self-adaption enhancement algorithm based on K-L transform is put forward. Covariance matrix is constructed by speech frame vectors; eigenvalues and corresponding to eigenvectors are got by decomposing eigenvalues of covariance matrix, orthogonal matrix is constructed by the eigenvectors; the transform coefficient vector is got by orthogonal transform of frame vectors with orthogonal matrix; through the analysis, selecting the appropriate eigenvalues and corresponding to eigenvectors reconstruct the new matrix; the transform coefficient vector is used as the inverse transformation to get the enhancement speech signal with reconstruction matrix. The enhanced speech extracted and transmitted to the decoder; reconstruction speech signal with interpolation technique. Under different SNR simulation experiments on different speech, and compared with the DCT encoding, The results show that the algorithm has high data compression rate, decoding speech is clear and natural, what＇s more, good self- adaption enhancement of speech is realized.