个性化耳廓旋转角测量与头相关传输函数定制

Measurement of Individual Pinna Rotation Angle and Customization of Head-Related Transfer Functions

耳廓旋转角的测量结果与头部初始位置有关,不同的耳廓旋转角测量方法可能影响个性化头相关传输函数(HRTF)的仰角分布特性.文中分别采用面部垂直参考面和法兰克福水平参考面测量并比较了60名受试者的耳廓旋转角,发现两种方法所得均值相差5°左右.为了分析耳廓旋转角对个性化HRTF空间分布的影响,将一个左耳廓在同一个椭球上按5°间隔旋转,得到耳廓旋转角分别为16°、11°和6°的3个计算模型.然后,用快速多极边界元方法(FM-BEM)计算分析了3个耦合模型的HRTF数据.结果表明:不同耳廓旋转角条件下,HRTF的耳廓高频谷点的频率差异可以达到约1.0 k Hz,某些角度的谷点幅度差异可达到约10 d B.最后,用空间坐标变换方法定制不同耳廓旋转角的个性化HRTF,结果表明,定制HRTF的耳廓谷点频率和幅度与直接通过数值计算的HRTF基本吻合,证明个性化耳廓旋转角定制方法有效.

The measured value of pinna rotation angle depends on subject＇s original head position, and the correspondingmeasurement methods of pinna rotation angle may affect the distribution of individual head-related transferfunctions （HRTFs） in various elevations. In this paper, both face-based vertical reference plane and Frankfurt referenceplane are used to measure and compare the pinna rotation angles of 60 human subjects, and a mean differenceof about 5° is obtained. Then, in order to discover the effect of pinna rotation angle on the spatial distributionof individual HRTFs, the left pinna is rotated on the same ellipsoidal head model with an interval of 5°, and threecalculation models respectively corresponding to the pinna rotation angles of 16°, 11° and 6° are obtained. Moreover,the HRTFs of the three coupling models are calculated and analyzed by means of the fast multi-pole boundaryelement method （FM-BEM）. The results show that the frequency discrepancy of the pinna notches at high frequenciesreaches about 1.0 kHz, and that the magnitude difference even reaches about 10 dB in some directions. In addition,from the individual HRTFs customized via spatial coordinate transformation, it is found that the frequenciesand magnitude of pinna notches of the customized HRTFs are similar to those of directly-calculated HRTFs, whichmeans that the proposed individual customization method for individual pinna rotation angle is effective.