Effect Of Individual Coupling Parameter Between Pinnae And Head On Sound Source Localization Factor

In the case of free field, head-related transfer functions(HRTFs) describe the acoustic transmission process from sound source to two ears and contain main spatial information of sound source, including the localization information of spatial sound source. They are the essential for VAD(Virtual Audition Display). In description, HRTFs reflect the subjects’ effect physical structure of point source acoustic wave filter, which are the physical quantities different from person to person, with individuals. In order to a better display result, the individual HRTFs data should be imported, in the other word, personalized customizations in VAD. However, personalized customizations are always very difficult because of the complexity of subjects’ physical structures and parameters.Therefore, when we want to simplify signal processing and acquire approximate individuals’ display effect, we are necessary to subdivide HRTFs. For example, ITD which is short for Interaural Time Difference, affecting sound source localization of low frequency(about below 2k Hz), can be composed of HRTFs’ minimum phase and pure delay, therefore it can be used to personalized customization of ITD; shoulder reflection mainly acts on sound source localization of low and medium frequency(about below 3~5k Hz), and it has a certain time delay with binaural sound pressure direct sound in time domain, so the shoulder reflection also can customizaion by itself; The HRTFs’ magnitude spectrums localization factor caused by pinnae mainly affect the high frequency(about above 5~6 k Hz) sound source localization, and because pinnae link to head, they should be analysis together.In fact, the different magnitude spectrums of individual HRTFs are uncorrelated with head shape and are correlated with the difference of pinnae. Therefore, if in order to further simplify the parameters, the head and the pinnae should be separated to research which will increase the coupling problem between them in this project. Overall, the coupling parameter between the pinnae and the head mainly includes the pinna rotation angle, pinna flare angle and pinna offset on the surface of the head.This paper, using human subjects head model database established by laser scan, sets up personalized approximation model, which means using head width, head depth and head height to fit ellipsoid approximation human subjects, and to joint the scanning pinna. On the basis, dealing with the different coupling of the pinnae and the head, and using boundary element method to calculate simulation approximate personalized HRTF. The coupling relationship of the pinnae and the head will be mainly analyzed: one is the effect for HRTF by pinna rotation angle and the pinna flare angle, and its application in the personalization, in the end, through psychoacoustic experiments, to analyze the actual effect in the VAD using personalized HRTFs which are get by personalized custom approximation coupling parameters. The other is to establish ellipsoid theory model, to analyze the influence of ITD through changing the relative position between pinna and head, and to expound the importance of the pinna offset.After all, in the paper,the research work provides an important basis and direction for the custom of personalized physiological parameters.