基于改进小波变换的语音基音周期检测

摘要

Pitch has been widely used in many areas,such as speech encoding,speech recognition,speech conversion,music retrieval and diagnosis of diseases of vocal system.Aiming at the disadvantages of pitch period measurement based on wavelet transform,e.g.,low accuracy,high complexity and poor robustness,and the problem of the difficulty of judging the speech pitch period under noisy speech environment,especially under non-stationary noising,the speech pitch period detection method based on the improved wavelet transform is proposed.Firstly,each frame of noisy signal is preprocessed to extract the information with speech segments and eliminate the DC component.Then,endpoint detection is conducted after window-added framing,and re-framing after filtering;and then the low frequency coefficient reconstructed signal is extracted after using wavelet decomposition.Finally,the pitch detection for the reconstructed signal is accomplished combining with the fourth order cumulative method.The experimental results show that under different noisy speech environment and low SNR condition,the accuracy of noisy speech pitch detection is improved.Comparing with the method of traditional wavelet transform,this method features better robustness and low computation complexity,these are helpful in speech pitch period detection.%基音在许多方面都有比较广泛的应用,比如语音编码、语音识别、语音转换、音乐检索以及发声系统疾病诊断等.针对目前很多小波变换方法在测量基音周期时存在的准确度低、复杂度高、鲁棒性差等缺点,以及在带噪语音环境下,特别是在非平稳噪声下比较难判断语音基音周期的问题,提出了一种基于改进小波变换的语音基音检测方法.首先将每帧带噪信号进行预处理,提取出有话段的信息,消除直流分量;然后在加窗分帧后先进行端点检测,滤波后再分帧;接着再利用小波分解后取低频系数重构信号;最后结合四阶累积法对重构信号进行基音检测.试验结果表明,该方法在不同带噪语音环境下和低信噪比条件下,提高了带噪语音基音检测的准确性.与传统的小波变换法相比,该方法鲁棒性好且计算复杂度低,有利于语音基音周期检测.