用于隐马尔可夫模型语音带宽扩展的激励分段扩展方法

摘要

Speech bandwidth expansion is used to enhance the auditory quality by artificially recovering the lost components in the high-band spectrum of narrow-band speech.Aiming at the problem of excitation expansion in speech source-filter extension model,a piecewise extension method was proposed.The higher spectrum part in the narrow-band excitation source and the white noise with the equivalent narrow-band excitation frame energy were used as the excitation sources for the lower and upper part of the extension band respectively.At last,the wideband excitation signal was composed of the above two and the original narrow band one.Experimental results of the wide band speech reconstruction with Hidden Markov Model (HMM) based spectrum envelope estimation show that the proposed method is superior to spectrum shift excitation expansion method.%语音带宽扩展通过人为恢复窄带语音的频谱带宽来提高语音听觉质量.针对源滤波器扩展模型的激励扩展问题,提出一种分段扩展方法.该方法在扩展带的低频段与高频段部分分别采用窄带激励源的高频部分与帧能量等效的白噪声作为激励信号,最后两者与原窄带激励组成宽带激励信号.基于隐马尔可夫模型(HMM)谱包络估计的宽带语音重构实验结果表明:该方法降低了重建语音的失真度,恢复重建的语音信号优于谱平移激励扩展方法.