Calculation and Analysis of Near-Field Head-Related Transfer Functions from a Simplified Head-Neck-Torso Model

2012 ◽  
Vol 29 (3) ◽  
pp. 034302 ◽  
Author(s):  
Ze-Wei Chen ◽  
Guang-Zheng Yu ◽  
Bo-Sun Xie ◽  
Shan-Qun Guan
Keyword(s):  
Transfer Functions ◽  
Near Field ◽  
Torso Model ◽  
Head Neck

Improved Analytical Models for Single- and Multi-layer Silver Superlenses

2009 ◽  
Vol 1182 ◽  
Author(s):  
Ciaran P Moore ◽  
Richard John Blaikie ◽  
Matthew D Arnold
Keyword(s):  
Transfer Functions ◽  
Near Field ◽  
Single Layer ◽  
Analytical Models ◽  
Full Field ◽  
Accurate Performance ◽  
Imaging Performance ◽  
Performance Estimates ◽  
Continuous Metal ◽  
Good Agreement

AbstractSpatial-frequency transfer functions are regularly used to model the imaging performance of near-field �superlens� systems. However, these do not account for interactions between the object that is being imaged and the superlens itself. As the imaging in these systems is in the near field, such interactions are important to consider if accurate performance estimates are to be obtained. We present here a simple analytical modification that can be made to the transfer function to account for near-field interactions for objects consisting of small apertures in otherwise-continuous metal screens. The modified transfer functions are evaluated by comparison with full-field finite-element simulations for representative single-layer and multi-layer silver superlenses, and good agreement is found.

scholarly journals Numerical simulations of near-field head-related transfer functions: Magnitude verification and validation with laser spark sources

2020 ◽  
Vol 148 (1) ◽  
pp. 153-166
Author(s):  
Sebastian T. Prepeliţă ◽  
Javier Gómez Bolaños ◽  
Ville Pulkki ◽  
Lauri Savioja ◽  
Ravish Mehra
Keyword(s):  
Numerical Simulations ◽  
Transfer Functions ◽  
Near Field ◽  
Verification And Validation ◽  
Laser Spark

Near-Field Virtual Audio Displays

2002 ◽  
Vol 11 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Douglas S. Brungart
Keyword(s):  
Transfer Functions ◽  
Near Field ◽  
Multimodal Interfaces ◽  
Sound Sources ◽  
Auditory Cues ◽  
Current State ◽  
Potential Applications ◽  
Technical Challenges ◽  
State Of Research ◽  
Virtual Audio

Although virtual audio displays are capable of realistically simulating relatively distant sound sources, they are not yet able to accurately reproduce the spatial auditory cues that occur when sound sources are located near the listener's head. Researchers have long recognized that the binaural difference cues that dominate auditory localization are independent of distance beyond 1 m but change systematically with distance when the source approaches with in 1 m of the listener's head. Recent research has shown that listeners are able to use these binaural cues to determine the distances of nearby sound sources. However, technical challenges in the collection and processing of near-field head-related transfer functions (HRTFs) have thus far prevented the construction of a fully functional near-field audio display. This paper summarizes the current state of research in the localization of nearby sound sources and outlines the technical challenges involved in the creation of a near-field virtual audio display. The potential applications of near-field displays in immersive virtual environments and multimodal interfaces are also discussed.

scholarly journals Substituting EMC emission measurement by field and cable scan method using measured transfer function

2013 ◽  
Vol 11 ◽  
pp. 183-188 ◽  
Author(s):  
D. Rinas ◽  
J. Jia ◽  
A. Zeichner ◽  
S. Frei
Keyword(s):  
Transfer Functions ◽  
Near Field ◽  
Good Alternative ◽  
Emission Measurement ◽  
Far Field ◽  
Field Calculation ◽  
Automotive Components ◽  
Anechoic Chambers ◽  
Cispr 25 ◽  
Space Requirements

Abstract. Today EMC emissions of automotive components are often measured in anechoic chambers by an antenna at fixed position according to CISPR 25 (ALSE-method). The antenna voltage often cannot sufficiently describe the behaviour of the measured electronic components and systems. Furthermore space requirements and costs are very high for the ALSE-method. Field- and cable-scan methods combined with near-field to far-field transformation techniques might be a good alternative. Residual reflections from the walls, the metallic floor, the measuring table, interaction of the antenna with the environment, and other factors affect the measurements. Thus, models which only regard the current distribution for near- and far field calculation cannot produce results equal to a chamber measurement. In this paper methods for computing transfer functions for the substitution of EMC antenna measurements with field- and cable scans in a specified calibration area are introduced. To consider influences of the environment, the environment is characterized in a first step and included with transfer functions in the calculation process for the equivalent ALSE-field.

scholarly journals Inverse Patch Transfer Functions Method as a Tool for Source Field Identification

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Dorian Vigoureux ◽  
Nicolas Totaro ◽  
Jonathan Lagneaux ◽  
Jean-Louis Guyader
Keyword(s):  
Background Noise ◽  
Experimental Validation ◽  
Transfer Functions ◽  
Near Field ◽  
Theoretical Background ◽  
Wall Pressure ◽  
Additional Measurement ◽  
Field Identification ◽  
Open Issue ◽  
Source Velocity

Many methods to detect, quantify, or reconstruct acoustic sources exist in the literature and are widely used in industry (near-field acoustic holography, inverse boundary element method, etc.). However, the source identification in a reverberant or nonanechoic environment on an irregularly shaped structure is still an open issue. In this context, the inverse patch transfer functions (iPTF) method first introduced by Aucejo et al. (2010, “Identification of Source Velocities on 3D Structures in Non-Anechoic Environments: Theoretical Background and Experimental Validation of the Inverse Patch Transfer Functions Method,” J. Sound Vib., 329(18), pp. 3691–3708) can be a suitable method. Indeed, the iPTF method has been developed to identify source velocity on complex geometries and in a nonanechoic environment. However, to obtain good results, the application of the method must follow rigorous criteria that were not fully investigated yet. In addition, as it was first defined, the iPTF method only provides source velocity while wall pressure or intensity should also give useful information to engineers. In the present article, a procedure to identify wall pressure and intensity of the source without any additional measurement is proposed. This procedure only needs simple numerical postprocessing. Using this new intensity identification, the influence of background noise, evanescent waves, and mesh discretization are illustrated on numerical examples. Finally, an experiment on a vibrating plate is shown to illustrate the iPTF procedure.

Effect of Sound Source Scattering on Measurement of Near-Field Head-Related Transfer Functions

2008 ◽  
Vol 25 (8) ◽  
pp. 2926-2929 ◽  
Author(s):  
Yu Guang-Zheng ◽  
Xie Bo-Sun ◽  
Rao Dan
Keyword(s):  
Sound Source ◽  
Transfer Functions ◽  
Near Field

Transfer functions in collection scanning near-field optical microscopy

1999 ◽  
Vol 172 (1-6) ◽  
pp. 171-179 ◽  
Author(s):  
Sergey I. Bozhevolnyi ◽  
Brian Vohnsen ◽  
Elena A. Bozhevolnaya
Keyword(s):  
Optical Microscopy ◽  
Transfer Functions ◽  
Near Field

Transfer Function Measurements on a Swirl Stabilized Premix Burner in an Annular Combustion Chamber

2004 ◽  
Author(s):  
Klaas Kunze ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Transfer Function ◽  
Heat Release ◽  
Combustion Chamber ◽  
Acoustic Waves ◽  
Velocity Fluctuation ◽  
Transfer Functions ◽  
Flow Direction ◽  
Near Field ◽  
Thermal Power ◽  
Annular Combustor

A generic swirl stabilized premix burner for natural gas is experimentally investigated in both a single burner test rig and in an annular combustion chamber. Flame transfer functions are measured relating the fluctuation of the flame heat release to the axial velocity fluctuation at the burner outlet. The OH-chemiluminescence signal of the flame, captured with a photomultiplier tube, is taken as an estimate for flame heat release, whereas the velocity fluctuation is measured with a hot wire probe. As integral measurements of the entire flame reveal important differences between the single burner and the annular combustor, locally resolved measurements are performed observing slices of the flame that are perpendicular to the main flow direction at a variable distance from the burner outlet. In both the single and the annular combustor a near field and a far field of the dynamic flame behavior can be distinguished. The annular combustor flame has a larger near field than the single combustor flame and a different shape in the presence of circumferential acoustic waves. Variation of swirl, thermal power and mass flow and comparison of the steady state heat release distribution within the flames lead to the result that the effective swirl in the annular combustor is lower than for the identical burner in the single burner combustor. When the difference in swirl is compensated for by modifying the burner configuration in the annular combustion chamber the flame transfer function is still not equal to the single combustor flame. The remaining difference can be attributed to the circumferential acoustic waves in the annular combustor which influence the flame shape.

Sign in / Sign up

Export Citation Format

Share Document