Individualized Head Related Transfer Functions

Human sound localization helps to pay attention to spatially separated speakers using interaural level and time differences as well as angle-dependent monaural spectral cues. In a monophonic teleconference, for instance, it is much more difficult to distinguish between different speakers due to missing binaural cues. Spatial positioning of the speakers by means of binaural reproduction methods using head-related transfer functions (HRTFs) enhances speech comprehension. These HRTFs are influenced by the torso, head and ear geometry as they describe the propagation path of the sound from a source to the ear canal entrance. Through this geometry-dependency, the HRTF is directional and subject-dependent. To enable a sufficient reproduction, individual HRTFs should be used. However, it is tremendously difficult to measure these HRTFs. For this reason this thesis proposes approaches to adapt the HRTFs applying individual anthropometric dimensions of a user. Since localization at low frequencies is mainly influenced by the interaural time difference, two models to adapt this difference are developed and compared with existing models. Furthermore, two approaches to adapt the spectral cues at higher frequencies are studied, improved and compared. Although the localization performance with individualized HRTFs is slightly worse than with individual HRTFs, it is nevertheless still better than with non-individual HRTFs, taking into account the measurement effort.

3-D Audio Using Loudspeakers is concerned with 3-D audio systems implemented using a pair of conventional loudspeakers. A well-known problem with these systems is the requirement that the listener be properly positioned for the 3-D illusion to function correctly. This book proposes using the tracked position of the listener's head to optimize the acoustical presentation, thus producing a much more realistic illusion over a larger listening area than existing loudspeaker 3-D audio systems. Head-tracking can be accomplished by applying pattern recognition techniques to images obtained from a video camera. Thus, an immersive audio environment can be created without donning headphones or other equipment. 3-D Audio Using Loudspeakers discusses the theory, implementation, and testing of a head-tracked loudspeaker 3-D audio system. Crosstalk cancellers that can be steered to the location of a tracked listener are described. The objective performance of these systems has been evaluated using simulations and acoustical measurements made at the ears of human subjects. Many sound localization experiments were also conducted; the results show that head-tracking both significantly improves localization when the listener is displaced from the ideal listening location, and also enables dynamic localization cues. Much of the theory and experimental results presented are also applicable to loudspeaker 3-D audio systems in general, not just head-tracked ones. 3-D Audio Using Loudspeakers is of interest to researchers studying virtual acoustic displays, and to engineers developing the same. The book serves as a valuable reference to anyone working in this field.

This is the first comprehensive, yet clearly presented, account of statistical methods for analysing spherical data. The analysis of data, in the form of directions in space or of positions of points on a spherical surface, is required in many contexts in the earth sciences, astrophysics and other fields, yet the methodology required is disseminated throughout the literature. Statistical Analysis of Spherical Data aims to present a unified and up-to-date account of these methods for practical use. The emphasis is on applications rather than theory, with the statistical methods being illustrated throughout the book by data examples.

The field of spatial hearing has exploded in the decade or so since Jens Blauert's classic work on acoustics was first published in English. This revised edition adds a new chapter that describes developments in such areas as auditory virtual reality (an important field of application that is based mainly on the physics of spatial hearing), binaural technology (modeling speech enhancement by binaural hearing), and spatial sound-field mapping. The chapter also includes recent research on the precedence effect that provides clear experimental evidence that cognition plays a significant role in spatial hearing.The remaining four chapters in this comprehensive reference cover auditory research procedures and psychometric methods, spatial hearing with one sound source, spatial hearing with multiple sound sources and in enclosed spaces, and progress and trends from 1972 (the first German edition) to 1983 (the first English edition) -- work that includes research on the physics of the external ear, and the application of signal processing theory to modeling the spatial hearing process. There is an extensive bibliography of more than 900 items.

Section 3. Capturing and controlling the spatial sound field. A study on 3D sound image control by two loudspeakers located in the transverse plane / K. Iida, T. Ishii, and Y. Ishii. Selective listening point audio based on blind signal separation and 3D audio effect / T. Nishino [und weitere]. Selective listening point audio based on blind signal separation and 3D audio effect / T. Nishino. Sweet spot size in virtual sound reproduction : A temporal analysis / Y. Lacouture Parodi and P. Rubak. Psychoacoustic evaluation of different methods for creating individualized, headphone-presented virtual auditory space from B-format room impulse responses / A. Kan, C. Jin, and A. van Schaik. Effects of microphone arrangements on the accuracy of a spherical microphone array (SENZI) in acquiring high-definition 3D sound space information / J. Kodama [und weitere]. Perception-based reproduction of spatial sound with directional audio coding / V. Pulkki [und weitere]. Capturing and recreating auditory virtual reality / R. Duraiswami [und weitere]. Reconstructing sound source directivity in virtual acoustic environments / M. Noisternig, F. Zotter, and B.F.G. Katz. Implementation of real-time room auralization using a surrounding loudspeaker array / T. Okamoto [und weitere]. Spatialisation in audio augmented reality using finger snaps / H. Gamper and T. Lokki. Generation of sound ball : Its theory and implementation / Y.-H. Kim [und weitere]. Estimation of high-resolution sound properties for realizing an editable sound-space system / T. Okamoto, Y. Iwaya, and Y. Suzuki -- Section 4. Applying virtual sound techniques in the real world. Binaural hearing assistance system based on frequency domain binaural model / T. Usagawa and Y. Chisaki. A spatial auditory display for telematic music performances / J. Braasch [und weitere]. Auditory orientation training system developed for blind people using PC-based wide-range 3-D sound technology / Y. Seki [und weitere]. Mapping musical scales onto virtual 3D spaces / J. Villegas and M. Cohen. Sonifying head-related transfer unctions / D. Cabrera and W.L. Martens. Effects of spatial cues on detectability of alarm signals in noisy environments / N. Kuroda [und weitere]. Binaural technique for active noise control assessment / Y. Watanabe and H. Hamada

This book covers all aspects of head-related transfer function (HRTF), from the fundamentals through to the latest applications, such as 3D sound systems. An introductory chapter defines HRTF, describes the coordinate system used in the book, and presents the most recent research achievements in the field. HRTF and sound localization in the horizontal and median planes are then explained, followed by discussion of individual differences in HRTF, solutions to this individuality (personalization of HRTF), and methods of sound image control for an arbitrary 3D direction, encompassing both classic theory and state of the art data. The relations between HRTF and sound image distance and between HRTF and speech intelligibility are fully explored, and measurement and signal processing methods for HRTF are examined in depth. Here, supplementary material is provided to enable readers to measure and analyze HRTF by themselves. In addition, some typical HRTF databases are compared. The final two chapters are devoted to the principles and applications of acoustic virtual reality. This clearly written book will be ideal for all who wish to learn about HRTF and how to use it in their research.

Book Soundscape Semiotics - Localization and Categorization is a research publication that covers original research on developments within the Soundscape Semiotics field of study. The book is a collection of reviewed scholarly contributions written by different authors. Each scholarly contribution represents a chapter and each chapter is complete in itself but related to the major topics and objectives. The chapters included in the book are divided in two section. First section - Advanced Signal Processing Methodologies for Soundscape Analysis contains 5 chapters, and second section - Human Hearing Estimations and Cognitive Soundscape Analysis 3 chapters. The target audience comprises scholars and specialists in the field.

This book systematically details the basic principles and applications of head-related transfer function (HRTF) and virtual auditory display (VAD), and reviews the latest developments in the field, especially those from the author’s own state-of-the-art research group. Head-Related Transfer Function and Virtual Auditory Display covers binaural hearing and the basic principles, experimental measurements, computation, physical characteristics analyses, filter design, and customization of HRTFs. It also details the principles and applications of VADs, including headphone and loudspeaker-based binaural reproduction, virtual reproduction of stereophonic and multi-channel surround sound, binaural room simulation, rendering systems for dynamic and real-time virtual auditory environments, psychoacoustic evaluation and validation of VADs, and a variety of applications of VADs. This guide provides all the necessary knowledge and latest results for researchers, graduate students, and engineers who work in the field of HRTF and VAD.