Murphy Peter J, McGuigan Kevin G, Walsh Michael, Colreavy Michael
Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland.
J Acoust Soc Am. 2008 Mar;123(3):1642-52. doi: 10.1121/1.2832651.
The harmonics-to-noise ratio (HNR) of the voiced speech signal has implicitly been used to infer information regarding the turbulent noise level at the glottis. However, two problems exist for inferring glottal noise attributes from the HNR of the speech wave form: (i) the measure is fundamental frequency (f0) dependent for equal levels of glottal noise, and (ii) any deviation from signal periodicity affects the ratio, not just turbulent noise. An alternative harmonics-to-noise ratio formulation [glottal related HNR (GHNR')] is proposed to overcome the former problem. In GHNR' a mean over the spectral range of interest of the HNRs at specific harmonic/between-harmonic frequencies (expressed in linear scale) is calculated. For the latter issue [(ii)] two spectral tilt measures are shown, using synthesis data, to be sensitive to glottal noise while at the same time being comparatively insensitive to other glottal aperiodicities. The theoretical development predicts that the spectral tilt measures reduce as noise levels increase. A conventional HNR estimator, GHNR' and two spectral tilt measures are applied to a data set of 13 pathological and 12 normal voice samples. One of the tilt measures and GHNR' are shown to provide statistically significant differentiating power over a conventional HNR estimator.
浊音语音信号的谐波噪声比（HNR）已被隐含地用于推断有关声门处湍流噪声水平的信息。然而，从语音波形的HNR推断声门噪声属性存在两个问题：（i）对于相等的声门噪声水平，该测量依赖于基频（f0）；（ii）与信号周期性的任何偏差都会影响该比率，而不仅仅是湍流噪声。为了克服前一个问题，提出了一种替代的谐波噪声比公式[与声门相关的HNR（GHNR'）]。在GHNR'中，计算特定谐波/谐波间频率（以线性比例表示）处的HNR在感兴趣的频谱范围内的平均值。对于后一个问题[（ii）]，使用合成数据表明，两种频谱倾斜测量对声门噪声敏感，同时对其他声门非周期性相对不敏感。理论推导预测，随着噪声水平的增加，频谱倾斜测量值会降低。将传统的HNR估计器、GHNR'和两种频谱倾斜测量应用于13个病理性和12个正常语音样本的数据集。结果表明，其中一种倾斜测量和GHNR'比传统的HNR估计器具有统计学上显著的区分能力。
