Personalization of head-related transfer functions in the median plane based on the anthropometry of the listener's pinnae

Abstract

A listener's own head-related transfer functions (HRTFs) are required for accurate three-dimensional sound image control. The HRTFs of other listeners often cause front-back confusion and errors in the perception of vertical angles. However, measuring the HRTFs of all listeners for all directions of a sound source is impractical because the measurement requires a special apparatus and a lot of time. The present study proposes a method for estimating the appropriate HRTFs for an individual listener. The proposed method estimates the frequencies of the two lowest spectral notches (N1 and N2), which play an important role in vertical localization, in the HRTF of an individual listener by anthropometry of the listener's pinnae. The best-matching HRTFs, of which N1 and N2 are the closest to the estimates, are then selected from an HRTF database. In order to examine the validity of the proposed method, localization tests in the upper median plane were performed using four subjects. The results revealed that the best-matching HRTFs provided approximately the same performance as the listener's own HRTFs for the target directions of the front and rear for all four subjects. For the upper target directions, however, the performance of the localization for some of the subjects decreased.

A high-resolution head-related transfer function and three-dimensional ear model database

“…The individualization, which is often based on the anthropometric data of humans, requires a basic understanding of the physical effects such as diffraction, refraction and interference on the body. 8 Meanwhile at lower frequencies, the body and head dimensions are of major importance, 7,28 the main influence on higher frequencies is caused by the pinna (see, for example, publications 16,22 ). For a detailed study of the relationship between the HRTF and the anthropometric measures, large databases, providing both, are necessary.…”

Frequency and amplitude estimation of the first peak of head-related transfer functions from individual pinna anthropometry

“…Compared with each of those two previous datasets, as a group the participants in the present study showed on average a deeper concha as evaluated by d CIPIC (60% deeper and 13% deeper, respectively), a wider concha as evaluated by W (39% wider and 15% wider, respectively), and a comparable concha height as evaluated by H (7% longer and 1% shorter, respectively). The greater similarity with the pinna measurements of Iida et al (2014) may possibly reflect the common inclusion of mostly Japanese participants, but the small sample sizes preclude any further discussion on racial tendencies in pinna geometry.…”

“…5 (d CIPIC , W, and H), corresponding pinna anthropometry available in the CIPIC database (Algazi et al, 2001; http:// interface.cipic.ucdavis.edu/sound/hrtf.html) are shown by dots on the left side of our data (respectively, "d 8 ," "d 3 ," and "d 1 "þ"d 2 "), and those listed in Iida et al (2014) are shown by dots on the right side (respectively, "x d ," "x 2 ," and "x 6 "þ"x 7 "). The range, mean, and standard deviation of each of these sets of measurements are listed in Table II.…”

“…2 for the typical position of all anatomical landmarks. For d CIPIC , W, and H (our data shown by crosses), equivalent distances available in two other databases are shown for comparison (small dots): Respectively, "d 8 ," "d 3 ," and "d 1 "þ"d 2 " for 74 pinnae of the CIPIC database (http://interface.cipic.ucdavis.edu/sound/hrtf.html) are shown by dots on the left side of our data; and, respectively, "x d ," "x 2 ," and "x 6 "þ"x 7 " for 54 pinnae listed in Iida et al (2014) are shown by dots on the right side of our data. indicates the coefficient of correlation (r) between original and estimated values of F 1 .…”

“…By backward elimination, they found the best three-parameter estimation model to include concha depth, width, and length, with a correlation coefficient of 0.56 and a mean absolute error of 160 Hz in F 1 . Although no details were given in that study concerning their specific definition of the concha depth measurement, it was subsequently revealed (Iida et al, 2014) to be the same as distance "d 8 " suggested in the documentation accompanying the CIPIC HRTF database (Algazi et al, 2001, Fig. 3): Briefly, "d 8 " is the concha depth measured perpendicular to a straight line joining the lateral surface of the tragus and the a) Author to whom correspondence should be addressed.…”