The Experts below are selected from a list of 9600 Experts worldwide ranked by ideXlab platform
Kazuhiro Iida - One of the best experts on this subject based on the ideXlab platform.
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effects of adding a spectral peak generated by the second pinna resonance to a parametric model of head related transfer functions on upper Median Plane sound localization
Applied Acoustics, 2018Co-Authors: Kazuhiro Iida, Yohji IshiiAbstract:Abstract The parametric head-related transfer function (HRTF) recomposed of only a spectral peak (P1) and two spectral notches (N1 and N2), which are respectively generated by the first resonance and the first and second anti-resonances of the pinna, has been reported to provide approximately the same localization performance as the measured HRTF for the front and rear directions. However, for the upper direction, the localization performance for some of the subjects decreased. In the present study, we conducted two localization tests with four listeners and seven target angles in the upper Median Plane (0–180°) to investigate whether adding a spectral peak (P2), generated by the second resonance of the pinna, can resolve this performance decrease. The results suggested that (1) the mean vertical localization error of the parametric HRTF recomposed of N1, N2, and P1 was significantly larger than that of the measured HRTFs at the target vertical angles of 30° and 120°; (2) by adding P2 to N1N2P1, the mean vertical localization error decreased at the target vertical angles of 0°, 30°, 90°, and 120°, and no statistically significant difference was observed between N1N2P1 + P2 and the measured HRTFs at any target vertical angle; and (3) a sound image was hardly perceived in the upper direction by reproducing only P2, but the presence of P2 to improve the salience of N1 was discussed.
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Generation of the Individual Head-Related Transfer Functions in the Upper Median Plane Based on the Anthropometry of the Listener’s Pinnae
2018 IEEE 7th Global Conference on Consumer Electronics (GCCE), 2018Co-Authors: Kazuhiro Iida, Hikaru Shimazaki, Masato OotaAbstract:In order to address the individual differences in the head-related transfer functions (HRTFs) of different listeners, the individualization of the HRTF has been investigated. In the present study, multiple regression analyses were carried out as objective variables of the amplitude level of each discrete frequency of the early HRTFs in the upper Median Plane and as explanatory variables of fourteen anthropometric parameters of the pinnae. The results showed the potential of generation of the individual HRTFs from the listener's anthropometry of the pinnae without any HRTF database.
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Roles of spectral peaks and notches in the head-related transfer functions in the upper Median Plane for vertical localization
Journal of the Acoustical Society of America, 2016Co-Authors: Kazuhiro Iida, Yohji IshiiAbstract:The parametric head-related transfer function (HRTF) recomposed of only a spectral peak (P1) generated by the first resonance of the pinna and two spectral notches (N1 and N2) generated by the first and the second anti-resonances of the pinna has been reported to provide approximately the same localization performance as the measured HRTF for the front and rear directions. However, for the upper directions, the localization performance for some of the subjects decreased. In the present study, we carried out two localization tests with seven target vertical angles in the upper Median Plane to clarify whether adding a spectral peak (P2) generated by the second resonance of the pinna can resolve this performance decrease. The results suggested the following: (1) N1, N2, and P1 play an important role in vertical localization; (2) localization performance was improved by adding P2 to N1N2P1 at the upper directions; (3) however, a sound image was hardly perceived in the upward direction by reproducing only P2, ...
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personalization of head related transfer functions in the Median Plane based on the anthropometry of the listener s pinnaea
Journal of the Acoustical Society of America, 2014Co-Authors: Kazuhiro Iida, Yohji Ishii, Shinsuke NishiokaAbstract: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...
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Mechanism for generating peaks and notches of head-related transfer functions in the Median Plane
The Journal of the Acoustical Society of America, 2012Co-Authors: Hironori Takemoto, Parham Mokhtari, Ryouichi Nishimura, Hiroaki Kato, Kazuhiro IidaAbstract:It has been suggested that the first spectral peak and the first two spectral notches of head-related transfer functions (HRTFs) are cues for sound localization in the Median Plane. Therefore, to examine the mechanism for generating spectral peaks and notches, HRTFs were calculated from four head shapes using the finite-difference time-domain method. The comparison between HRTFs calculated from the whole head and the pinna-related transfer functions calculated from the segmented pinna indicated that the pinna determines the basic peak–notch pattern of the HRTFs. An analysis of the distribution patterns of pressure nodes and anti-nodes on the pinna computed in the steady state for sinusoidal excitations confirmed that the first three peaks correspond to the first three normal modes of the pinna. The analysis also revealed that at the first spectral notch frequencies, one or two anti-nodes appeared in the cymba and the triangular fossa, and a node developed in the concha. Furthermore, according to changes in the instantaneous pressure distribution patterns on the pinna, three types of mechanisms were hypothesized for inducing the node in the concha depending on the source elevation angle.
Hiroaki Kato - One of the best experts on this subject based on the ideXlab platform.
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frequency and amplitude estimation of the first peak of head related transfer functions from individual pinna anthropometry
Journal of the Acoustical Society of America, 2015Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:The first (lowest) peak of head-related transfer functions (HRTFs) is known to be a concha depth resonance and a spectral cue in human sound localization. However, there is still no established model to estimate its center-frequency F1 and amplitude A1 from pinna anthropometry. Here, with geometries of 38 pinnae measured and their Median-Plane HRTFs calculated by numerical simulation, linear regression models were evaluated in estimating F1 and A1 from 25 concha depth and aperture measurements. F1 was best estimated (correlation coefficient r = 0.84, mean absolute error MAE = 118 Hz) by lateral distances from the base of the posterior cavum concha to the outer surface of the antitragus and antihelix (longest measures of concha depth). A1 was best estimated (r = 0.83, MAE = 0.84 dB) by the lateral distance from the ear-canal entrance to the side of the cheek near the anterior notch (shortest measure of concha depth) and by the equivalent diameter of the concha aperture. These results suggest that the first resonance's quarter-wavelength corresponds to the longest lateral extent of the concha and that its energy lost to the surrounding air depends on the concha aperture and the cavum concha's shortest lateral depth.
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frequency and amplitude estimation of the first peak of head related transfer functions from individual pinna anthropometry
Journal of the Acoustical Society of America, 2015Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:The first (lowest) peak of head-related transfer functions (HRTFs) is known to be a concha depth resonance and a spectral cue in human sound localization. However, there is still no established model to estimate its center-frequency F1 and amplitude A1 from pinna anthropometry. Here, with geometries of 38 pinnae measured and their Median-Plane HRTFs calculated by numerical simulation, linear regression models were evaluated in estimating F1 and A1 from 25 concha depth and aperture measurements. F1 was best estimated (correlation coefficient r = 0.84, mean absolute error MAE = 118 Hz) by lateral distances from the base of the posterior cavum concha to the outer surface of the antitragus and antihelix (longest measures of concha depth). A1 was best estimated (r = 0.83, MAE = 0.84 dB) by the lateral distance from the ear-canal entrance to the side of the cheek near the anterior notch (shortest measure of concha depth) and by the equivalent diameter of the concha aperture. These results suggest that the first...
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Mechanism for generating peaks and notches of head-related transfer functions in the Median Plane
The Journal of the Acoustical Society of America, 2012Co-Authors: Hironori Takemoto, Parham Mokhtari, Ryouichi Nishimura, Hiroaki Kato, Kazuhiro IidaAbstract:It has been suggested that the first spectral peak and the first two spectral notches of head-related transfer functions (HRTFs) are cues for sound localization in the Median Plane. Therefore, to examine the mechanism for generating spectral peaks and notches, HRTFs were calculated from four head shapes using the finite-difference time-domain method. The comparison between HRTFs calculated from the whole head and the pinna-related transfer functions calculated from the segmented pinna indicated that the pinna determines the basic peak–notch pattern of the HRTFs. An analysis of the distribution patterns of pressure nodes and anti-nodes on the pinna computed in the steady state for sinusoidal excitations confirmed that the first three peaks correspond to the first three normal modes of the pinna. The analysis also revealed that at the first spectral notch frequencies, one or two anti-nodes appeared in the cymba and the triangular fossa, and a node developed in the concha. Furthermore, according to changes in the instantaneous pressure distribution patterns on the pinna, three types of mechanisms were hypothesized for inducing the node in the concha depending on the source elevation angle.
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Pinna sensitivity patterns reveal reflecting and diffracting surfaces that generate the first spectral notch in the front Median Plane
2011 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2011Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:Finite-Difference Time Domain (FDTD) acoustic simulation was used to calculate Pinna-Related Transfer Functions (PRTFs) of the KEMAR manikin's DB60 pinna. A baseline set of 25 PRTFs were first calculated at regular intervals of elevation angle in the front Median Plane. The simulation was then repeated 1784 times, corresponding to every unique, single-voxel perturbation of the pinna's outer surface geometry. All perturbed PRTFs were compared with the baseline set, in order to precisely quantify the frequency shifts in all the spectral peaks and notches up to 14 kHz. This paper focuses on the pinna sensitivity patterns for the first spectral notch Nl, known to be an auditory cue to elevation in the Median Plane. In particular, Nl sensitivity patterns revealed the elevation dependence of broad areas of the pinna's upper structures that are involved in reflection, and the role of the tragus region involved in diffraction.
Bernhard Laback - One of the best experts on this subject based on the ideXlab platform.
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modeling the effects of sensorineural hearing loss on sound localization in the Median Plane
Trends in hearing, 2016Co-Authors: Robert Baumgartner, Piotr Majdak, Bernhard LabackAbstract:Listeners use monaural spectral cues to localize sound sources in sagittal Planes (along the up-down and front-back directions). How sensorineural hearing loss affects the salience of monaural spectral cues is unclear. To simulate the effects of outer-hair-cell (OHC) dysfunction and the contribution of different auditory-nerve fiber types on localization performance, we incorporated a nonlinear model of the auditory periphery into a model of sagittal-Plane sound localization for normal-hearing listeners. The localization model was first evaluated in its ability to predict the effects of spectral cue modifications for normal-hearing listeners. Then, we used it to simulate various degrees of OHC dysfunction applied to different types of auditory-nerve fibers. Predicted localization performance was hardly affected by mild OHC dysfunction but was strongly degraded in conditions involving severe and complete OHC dysfunction. These predictions resemble the usually observed degradation in localization performanc...
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Modeling the Effects of Sensorineural Hearing Loss on Sound Localization in the Median Plane
SAGE Publishing, 2016Co-Authors: Robert Baumgartner, Piotr Majdak, Bernhard LabackAbstract:Listeners use monaural spectral cues to localize sound sources in sagittal Planes (along the up-down and front-back directions). How sensorineural hearing loss affects the salience of monaural spectral cues is unclear. To simulate the effects of outer-hair-cell (OHC) dysfunction and the contribution of different auditory-nerve fiber types on localization performance, we incorporated a nonlinear model of the auditory periphery into a model of sagittal-Plane sound localization for normal-hearing listeners. The localization model was first evaluated in its ability to predict the effects of spectral cue modifications for normal-hearing listeners. Then, we used it to simulate various degrees of OHC dysfunction applied to different types of auditory-nerve fibers. Predicted localization performance was hardly affected by mild OHC dysfunction but was strongly degraded in conditions involving severe and complete OHC dysfunction. These predictions resemble the usually observed degradation in localization performance induced by sensorineural hearing loss. Predicted localization performance was best when preserving fibers with medium spontaneous rates, which is particularly important in view of noise-induced hearing loss associated with degeneration of this fiber type. On average across listeners, predicted localization performance was strongly related to level discrimination sensitivity of auditory-nerve fibers, indicating an essential role of this coding property for localization accuracy in sagittal Planes
Parham Mokhtari - One of the best experts on this subject based on the ideXlab platform.
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frequency and amplitude estimation of the first peak of head related transfer functions from individual pinna anthropometry
Journal of the Acoustical Society of America, 2015Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:The first (lowest) peak of head-related transfer functions (HRTFs) is known to be a concha depth resonance and a spectral cue in human sound localization. However, there is still no established model to estimate its center-frequency F1 and amplitude A1 from pinna anthropometry. Here, with geometries of 38 pinnae measured and their Median-Plane HRTFs calculated by numerical simulation, linear regression models were evaluated in estimating F1 and A1 from 25 concha depth and aperture measurements. F1 was best estimated (correlation coefficient r = 0.84, mean absolute error MAE = 118 Hz) by lateral distances from the base of the posterior cavum concha to the outer surface of the antitragus and antihelix (longest measures of concha depth). A1 was best estimated (r = 0.83, MAE = 0.84 dB) by the lateral distance from the ear-canal entrance to the side of the cheek near the anterior notch (shortest measure of concha depth) and by the equivalent diameter of the concha aperture. These results suggest that the first resonance's quarter-wavelength corresponds to the longest lateral extent of the concha and that its energy lost to the surrounding air depends on the concha aperture and the cavum concha's shortest lateral depth.
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frequency and amplitude estimation of the first peak of head related transfer functions from individual pinna anthropometry
Journal of the Acoustical Society of America, 2015Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:The first (lowest) peak of head-related transfer functions (HRTFs) is known to be a concha depth resonance and a spectral cue in human sound localization. However, there is still no established model to estimate its center-frequency F1 and amplitude A1 from pinna anthropometry. Here, with geometries of 38 pinnae measured and their Median-Plane HRTFs calculated by numerical simulation, linear regression models were evaluated in estimating F1 and A1 from 25 concha depth and aperture measurements. F1 was best estimated (correlation coefficient r = 0.84, mean absolute error MAE = 118 Hz) by lateral distances from the base of the posterior cavum concha to the outer surface of the antitragus and antihelix (longest measures of concha depth). A1 was best estimated (r = 0.83, MAE = 0.84 dB) by the lateral distance from the ear-canal entrance to the side of the cheek near the anterior notch (shortest measure of concha depth) and by the equivalent diameter of the concha aperture. These results suggest that the first...
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Mechanism for generating peaks and notches of head-related transfer functions in the Median Plane
The Journal of the Acoustical Society of America, 2012Co-Authors: Hironori Takemoto, Parham Mokhtari, Ryouichi Nishimura, Hiroaki Kato, Kazuhiro IidaAbstract:It has been suggested that the first spectral peak and the first two spectral notches of head-related transfer functions (HRTFs) are cues for sound localization in the Median Plane. Therefore, to examine the mechanism for generating spectral peaks and notches, HRTFs were calculated from four head shapes using the finite-difference time-domain method. The comparison between HRTFs calculated from the whole head and the pinna-related transfer functions calculated from the segmented pinna indicated that the pinna determines the basic peak–notch pattern of the HRTFs. An analysis of the distribution patterns of pressure nodes and anti-nodes on the pinna computed in the steady state for sinusoidal excitations confirmed that the first three peaks correspond to the first three normal modes of the pinna. The analysis also revealed that at the first spectral notch frequencies, one or two anti-nodes appeared in the cymba and the triangular fossa, and a node developed in the concha. Furthermore, according to changes in the instantaneous pressure distribution patterns on the pinna, three types of mechanisms were hypothesized for inducing the node in the concha depending on the source elevation angle.
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Pinna sensitivity patterns reveal reflecting and diffracting surfaces that generate the first spectral notch in the front Median Plane
2011 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2011Co-Authors: Parham Mokhtari, Hironori Takemoto, Ryouichi Nishimura, Hiroaki KatoAbstract:Finite-Difference Time Domain (FDTD) acoustic simulation was used to calculate Pinna-Related Transfer Functions (PRTFs) of the KEMAR manikin's DB60 pinna. A baseline set of 25 PRTFs were first calculated at regular intervals of elevation angle in the front Median Plane. The simulation was then repeated 1784 times, corresponding to every unique, single-voxel perturbation of the pinna's outer surface geometry. All perturbed PRTFs were compared with the baseline set, in order to precisely quantify the frequency shifts in all the spectral peaks and notches up to 14 kHz. This paper focuses on the pinna sensitivity patterns for the first spectral notch Nl, known to be an auditory cue to elevation in the Median Plane. In particular, Nl sensitivity patterns revealed the elevation dependence of broad areas of the pinna's upper structures that are involved in reflection, and the role of the tragus region involved in diffraction.
Youngjin Park - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of three different standard head-related transfer functions using an elevation discrimination task for virtual sources displayed in the Median Plane
ICCAS 2010, 2010Co-Authors: Hyun Jo, William L. Martens, Youngjin ParkAbstract:The performance in controlling elevation effect of virtual sources displayed in the Median Plane was tested for three different sets of standard head-related transfer functions (HRTFs) using an elevation discrimination task. The three candidate sets compared included a representative subject's customized head-related impulse response (HRIR), mean-HRIR derived from the CIPIC database, and mean-HRIR of individually customized HRIRs proposed by Jo et al.. The goal of the current study was to find the best standard HRTF dataset for many listeners, with particular emphasis on its ability to work well without requiring a given listener to engage in any customization procedure. A two interval two alternative forced choice (2-AFC) discrimination for virtual source elevation was used to find how easy it was for subjects to distinguish between elevation angles within 15 or 30 degrees of each other. The simple question asked of each subject was “Which sound source is perceived as higher between the two presented.” To compare the performance of elevation discrimination, individually measured HRTF, individually customized HRTF, and HRTF of KEMAR dummy were also used. The results from six subjects showed that even though the listeners' own measured HRTFs were used, they could not discriminate elevation well for sources differing only in terms of polar angle in the Median Plane. Similar poor performance was observed when using HRIRs from KEMAR. With regard to the search for standard filters for general use across listeners, a representative subject's customized HRTF, which was based on the method provided by Hwang, et al. was preferred as it supported the best discrimination performance between the tested candidate HRTF datasets.
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enhanced vertical perception through head related impulse response customization based on pinna response tuning in the Median Plane
IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences, 2008Co-Authors: Kihoon Shin, Youngjin ParkAbstract:Human's ability to perceive elevation of a sound and distinguish whether a sound is coming from the front or rear strongly depends on the monaural spectral features of the pinnae. In order to realize an effective virtual auditory display by HRTF (head-related transfer function) customization, the pinna responses were isolated from the Median HRIRs (head-related impulse responses) of 45 individual HRIRs in the CIPIC HRTF database and modeled as linear combinations of 4 or 5 basic temporal shapes (basis functions) per each elevation on the Median Plane by PCA (principal components analysis) in the time domain. By tuning the weight of each basis function computed for a specific height to replace the pinna response in the KEMAR HRIR at the same height with the resulting customized pinna response and listening to the filtered stimuli over headphones, 4 individuals with normal hearing sensitivity were able to create a set of HRIRs that outperformed the KEMAR HRIRs in producing vertical effects with reduced front/back ambiguity in the Median Plane. Since the monaural spectral features of the pinnae are almost independent of azimuthal variation of the source direction, similar vertical effects could also be generated at different azimuthal directions simply by varying the ITD (interaural time difference) according to the direction as well as the size of each individual's own head.
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modeling of Median Plane head related impulse responses using a set of general basis functions
Transactions of The Korean Society for Noise and Vibration Engineering, 2008Co-Authors: Sungmook Hwang, Youngjin Park, Younsik ParkAbstract:A principal components analysis (PCA) of the Median-Plane head-related impulse responses (HRIRs) in the CIPIC HRTF database reveals that the individual HRIRs in the Median Plane can be adequately reconstructed by a linear combination of 12 orthonormal basis functions. These basis functions can be used to model arbitrary Median-Plane HRIRs, which are not included in the process to obtain the basis functions. Memory size can be reduced up to 5-fold depending on the number of HRIRs to be modeled. To clarify whether these basis functions can be used to model other set of arbitrary Median Plane HRIRs, a numerical error analysis for modeling and a series of subjective listening tests were carried out using the measured and modeled HRIRs. The results showed that the set of individual HRIRs in the Median Plane, which were measured in our lab using different measurement conditions, techniques, and source positions, can be modeled with reasonable accuracy. All subjects, involved in the subjective listening test, reported not only the accurate vertical perception but also the front-back discrimination with the modeled HRIRs based on 12 basis functions.
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Interpretations on principal components analysis of head-related impulse responses in the Median Plane.
The Journal of the Acoustical Society of America, 2008Co-Authors: Sungmok Hwang, Youngjin ParkAbstract:A principal components analysis of the Median-Plane head-related impulse responses (HRIRs) in the CIPIC HRTF database reveals that the individual HRIRs can be reconstructed by a linear combination of 12 principal components (PCs) within 5% of error in the least-squares sense. The PCs include the intersubject and interelevation variations in the Median-Plane HRIRs. Each PC provides sound cues for the front–back discrimination and/or the vertical perception. There exist common systematic elevation dependencies in the weights of lower-numbered PCs which contribute to the pinna/head diffractions, whereas the elevation dependencies in the weights of higher-numbered PCs are different from subject to subject.
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Sound source localization in Median Plane using artificial ear
2008 International Conference on Control Automation and Systems, 2008Co-Authors: Sungmok Hwang, Youngjin Park, Younsik ParkAbstract:Sound source localization is the method using the measurements of the acoustic signals from microphone arrays in acoustical engineering. This technique has been used broadly in 3-D sound technology, humanoid robot and teleconferencing and so on. For robot industry, their ultimate purpose is to be with human being. This is why the industry is demanding applicable robotpsilas auditory system in the form of artificial ears like humanpsilas external ear such as ear pinna. It has more benefits to make use of auditory system with ear pinna to humanoid robots for HRI. In this paper, we propose a specific sound source localization method using a pair of artificial ears, each of which consisting of a single ear pinna and two microphones. The feasibility and localization performance of proposed method for speech signal in Median Plane is shown. Through the experiment in office environment, we confirm that robots with artificial ears can estimate the elevation angle of speech signal just using two microphone output signals.