改进的子波过零电子耳蜗语音编码策略

Improved Speech Coding Strategy Based on Wavelet Transform Zero-Crossings for Cochlear Implants

  • 摘要: 提出改进的倍频程小波过零刺激方案(WZCS),以改善电子耳蜗语音编码策略的性能. 在语音信号倍频程小波变换域的过零点通过幅度调制合成刺激脉冲,并基于Matlab对该算法和连续间隔采样(CIS)、通道专用采样序列(CSSS)、频率幅度联合调制编码(FAME)等编码策略进行仿真,将合成信号与原始语音、合成信号频谱与原始语音频谱进行了相关性分析. 仿真结果表明, WZCS算法合成信号的频谱与原始语音信号的频谱相关系数最大,WZCS算法合成信号频谱与原始语音最为相关,且相关显著,即与其他算法相比其保留了原始语音信号的更多频率和相位成分.

     

    Abstract: To enhance the performance of speech coding strategy of cochlear implants, wavelet transform zero-crossings stimulation (WZCS) strategy based on one-octave wavelet transform is presented. Zero-crossings of processed signal were derived in the domain of wavelet transform and further the amplitude of signals was modulated by corresponding temporal envelope to form the synthesized stimulus. Four strategies of WZCS, continuous interleaved sampling (CIS), channel specific sampling sequences(CSSS), frequency amplitude modulation encoding(FAME) were simulated using Matlab. Correlativity analysis between synthesized stimuli and original signal, also between their spectra and that of original speech, was implemented. Compared to other 3 strategies, WZCS obtains the highest correlation coefficient between spectrum of synthesized signal and that of original speech, that is to say, the spectrum of synthesized signal through WZCS strategy is the most correlated to that of original speech. The algorithm presented in this paper keeps more frequency components and phase information of original speech in synthesized stimulus compared to other strategies.

     

/

返回文章
返回
Baidu
map