A Study on Extraction of Robust Parameters of Individuality for Speaker Recognition Based on Acoustic Theory of Speech Production

为了阐明声道解剖结构、声学参数和听觉之间的关系，我们发展了一种新的方法，从持续元音的磁共振图像中测量声道的三维形状。从MR图像测量了三个成年男性、三个女性和一个男孩发音的五个日语元音的声道形状的尺寸。系统研究了男性、女性和儿童声道形态和声学参数的差异。结果表明，声道形状的尺寸不均匀对声学特性没有本质的影响。本研究讨论了从男性和女性的MR图像测量的元音的声道形状的个性。研究了受试者声道大小的差异及其对声学特性的影响。元音质量的知觉相似性测试显示…主要依靠声道长度可以实现从女性元音到男性元音的更多归一化。结果表明，对于相同的男性元音，发音的“不变性”可能是声学参数(前三个共振峰频率F1、F2和F3，它们在听觉中起重要作用)，而不是发音模拟。为了从语音信号中稳定地估计说话人个体参数，引入源-滤波模型来描述语音产生，其中语音信号被看作是声源激励的滤波器(声道)的输出。提出了一种基于直接子空间的状态空间系统辨识算法来分析模型参数的语音分析方法。实验结果表明，该方法不仅可以很好地估计包括共振峰频率较高的声道参数，而且可以很好地估计声源参数，除了说话人识别外，该项目的研究成果有望应用于语音合成、感知、语音转换、编码、识别等几乎所有的语音研究领域。较少

In order to elucidate the relation among the anatomical structure of the vocal tract, the acoustic parameters, and the auditory perception, we have developed a new method to measure three dimensional vocal tract shapes from magnetic resonance (MR) images of sustained vowels. The dimensions of the vocal tract shapes of five Japanese vowels phonated by three adult males, three females and a boy are measured from the MR images. Differences of vocal tract shapes and acoustic parameters among male, female and child are systematically investigated. The result showed that the non-uniformity in the dimensions of the vocal tract shape had no essential effect on the acoustic characteristics.In this research individualities of the vocal tract shape of vowels measured from MR images of males and females were discussed. Differences in dimensions of the vocal tract of the subjects and their effects on acoustic characteristics were investigated. Perceptual similarity tests of vowel quality showed tha … More t normalization of vowels from females to males could be made by relying largely on the vocal tract length.Vowels of the males were carefully compared at the articulatory and acoustic levels. The result suggested that, for an identical vowel of males, the "invariance" of the phonation may be acoustic parameters (the first three formant frequencies F1, F2 and F3, which are important in auditory perception) rather than the articulatory simulation. It was also showed that the higher formant frequencies (F4, F5) are stable factors of speaker individuality.To stably estimate speaker individual parameters from a speech signal, a source-filter model was introduced to represent the speech production, in which a speech signal is regarded as the output of a filter (the vocal tract) excited by a sound source.A novel speech analysis method was proposed to analyze the model parameters by using a direct subspace-based state-space system identification algorithm. Experimental results showed that not only the vocal tract parameters including the higher formant frequencies but also the source parameters can be estimated quite well.In addition to speaker recognition, the results of this project can be expected to be applied in almost all the speech research areas, such as synthesis, perception, voice conversion, coding, recognition. Less