title: Insights into head-related transfer function: Spatial dimensionality and continuous representation.
abstract: This paper studies head-related transfer function (HRTF) sampling and synthesis in a three-dimensional auditory scene based on a general modal decomposition of the HRTF in all frequency-range-angle domains. The main finding is that the HRTF decomposition with the derived spatial basis function modes can be well approximated by a finite number, which is defined as the spatial dimensionality of the HRTF. The dimensionality determines the minimum number of parameters to represent the HRTF corresponding to all directions and also the required spatial resolution in HRTF measurement. The general model is further developed to a continuous HRTF representation, in which the normalized spatial modes can achieve HRTF near-field and far-field representations in one formulation. The remaining HRTF spectral components are compactly represented using a Fourier spherical Bessel series, where the aim is to generate the HRTF with much higher spectral resolution in fewer parameters from typical measurements, which usually have limited spectral resolution constrained by sampling conditions. A low-computation algorithm is developed to obtain the model coefficients from the existing measurements. The HRTF synthesis using the proposed model is validated by three sets of data: (i) synthetic HRTFs from the spherical head model, (ii) the MIT KEMAR (Knowles Electronics Mannequin for Acoustics Research) data, and (iii) 45-subject CIPIC HRTF measurements.
authors.affiliation: Department of Information Engineering, Research School of Information Sciences and Engineering, College of Engineering and Computer Science, The Australian National University, Canberra ACT 0200, Australia. wen.zhang@anu.edu.au
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Thushara D
authors.initials: TD
authors.lastname: Abhayapala
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Kennedy
authors.forename: Ramani
authors.initials: R
authors.lastname: Duraiswami
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000465:Algorithms; D000669:Amplifiers, Electronic; D001307:Auditory Perception; D003198:Computer Simulation; D003463:Cues; D006257:Head / Q000033:anatomy & histology / Q000502:physiology*; D019416:Head Movements; D006801:Humans; D008954:Models, Biological; D011312:Pressure; D011571:Psychoacoustics; D015203:Reproducibility of Results; D013017:Sound Localization; D013028:Space Perception; D013997:Time Factors; D014159:Transducers