The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Dinesh Manocha - One of the best experts on this subject based on the ideXlab platform.
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Diffraction Kernels for Interactive Sound Propagation in Dynamic Environments
IEEE transactions on visualization and computer graphics, 2018Co-Authors: Atul Rungta, Ravish Mehra, Carl Schissler, Nicholas Rewkowski, Dinesh ManochaAbstract:We present a novel method to generate plausible diffraction effects for interactive Sound Propagation in dynamic scenes. Our approach precomputes a diffraction kernel for each dynamic object in the scene and combines them with interactive ray tracing algorithms at runtime. A diffraction kernel encapsulates the Sound interaction behavior of individual objects in the free field and we present a new source placement algorithm to significantly accelerate the precomputation. Our overall Propagation algorithm can handle highly-tessellated or smooth objects undergoing rigid motion. We have evaluated our algorithm's performance on different scenarios with multiple moving objects and demonstrate the benefits over prior interactive geometric Sound Propagation methods. We also performed a user study to evaluate the perceived smoothness of the diffracted field and found that the auditory perception using our approach is comparable to that of a wave-based Sound Propagation method.
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source and listener directivity for interactive wave based Sound Propagation
IEEE Transactions on Visualization and Computer Graphics, 2014Co-Authors: Ravish Mehra, Lakulish Antani, Sujeong Kim, Dinesh ManochaAbstract:We present an approach to model dynamic, data-driven source and listener directivity for interactive wave-based Sound Propagation in virtual environments and computer games. Our directional source representation is expressed as a linear combination of elementary spherical harmonic (SH) sources. In the preprocessing stage, we precompute and encode the propagated Sound fields due to each SH source. At runtime, we perform the SH decomposition of the varying source directivity interactively and compute the total Sound field at the listener position as a weighted sum of precomputed SH Sound fields. We propose a novel plane-wave decomposition approach based on higher-order derivatives of the Sound field that enables dynamic HRTF-based listener directivity at runtime. We provide a generic framework to incorporate our source and listener directivity in any offline or online frequency-domain wave-based Sound Propagation algorithm. We have integrated our Sound Propagation system in Valve's Source game engine and use it to demonstrate realistic acoustic effects such as Sound amplification, diffraction low-passing, scattering, localization, externalization, and spatial Sound, generated by wave-based Propagation of directional sources and listener in complex scenarios. We also present results from our preliminary user study.
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SIVE@VR - Wave-based Sound Propagation for VR applications
2014 IEEE VR Workshop: Sonic Interaction in Virtual Environments (SIVE), 2014Co-Authors: Ravish Mehra, Dinesh ManochaAbstract:Realistic Sound effects are extremely important in VR to improve the sense of presence and immersion. They augment the visual sense of the user and can help reduce simulation fatigue. Sound can provide 3D spatial cues outside eld of view and help create high-fidelity VR training simulations. Current Sound Propagation techniques are based on heuristic approaches or simple line-of-sight based geometric techniques. These techniques cannot capture important Sound effects such as diffraction, interference, focusing. For VR applications, there is a need for high-fidelity, accurate Sound Propagation. In order to model Sound Propagation accurately, it is important to model wave-based Sound Propagation. We present a set of efficient wave-based Propagation techniques for VR applications that can handle large scenes, directional Sound sources, and generate spatial Sound. Our technique has been integrated in Valve's game engine and we use it to demonstrate realistic acoustic effects such as diffraction, high-order re ection, interference, directivity, and spatialization, in complex scenarios.
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ad frustum adaptive frustum tracing for interactive Sound Propagation
IEEE Transactions on Visualization and Computer Graphics, 2008Co-Authors: Anish Chandak, Christian Lauterbach, Micah Taylor, Zhimin Ren, Dinesh ManochaAbstract:We present an interactive algorithm to compute Sound Propagation paths for transmission, specular reflection and edge diffraction in complex scenes. Our formulation uses an adaptive frustum representation that is automatically sub-divided to accurately compute intersections with the scene primitives. We describe a simple and fast algorithm to approximate the visible surface for each frustum and generate new frusta based on specular reflection and edge diffraction. Our approach is applicable to all triangulated models and we demonstrate its performance on architectural and outdoor models with tens or hundreds of thousands of triangles and moving objects. In practice, our algorithm can perform geometric Sound Propagation in complex scenes at 4-20 frames per second on a multi-core PC.
Ravish Mehra - One of the best experts on this subject based on the ideXlab platform.
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Diffraction Kernels for Interactive Sound Propagation in Dynamic Environments
IEEE transactions on visualization and computer graphics, 2018Co-Authors: Atul Rungta, Ravish Mehra, Carl Schissler, Nicholas Rewkowski, Dinesh ManochaAbstract:We present a novel method to generate plausible diffraction effects for interactive Sound Propagation in dynamic scenes. Our approach precomputes a diffraction kernel for each dynamic object in the scene and combines them with interactive ray tracing algorithms at runtime. A diffraction kernel encapsulates the Sound interaction behavior of individual objects in the free field and we present a new source placement algorithm to significantly accelerate the precomputation. Our overall Propagation algorithm can handle highly-tessellated or smooth objects undergoing rigid motion. We have evaluated our algorithm's performance on different scenarios with multiple moving objects and demonstrate the benefits over prior interactive geometric Sound Propagation methods. We also performed a user study to evaluate the perceived smoothness of the diffracted field and found that the auditory perception using our approach is comparable to that of a wave-based Sound Propagation method.
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source and listener directivity for interactive wave based Sound Propagation
IEEE Transactions on Visualization and Computer Graphics, 2014Co-Authors: Ravish Mehra, Lakulish Antani, Sujeong Kim, Dinesh ManochaAbstract:We present an approach to model dynamic, data-driven source and listener directivity for interactive wave-based Sound Propagation in virtual environments and computer games. Our directional source representation is expressed as a linear combination of elementary spherical harmonic (SH) sources. In the preprocessing stage, we precompute and encode the propagated Sound fields due to each SH source. At runtime, we perform the SH decomposition of the varying source directivity interactively and compute the total Sound field at the listener position as a weighted sum of precomputed SH Sound fields. We propose a novel plane-wave decomposition approach based on higher-order derivatives of the Sound field that enables dynamic HRTF-based listener directivity at runtime. We provide a generic framework to incorporate our source and listener directivity in any offline or online frequency-domain wave-based Sound Propagation algorithm. We have integrated our Sound Propagation system in Valve's Source game engine and use it to demonstrate realistic acoustic effects such as Sound amplification, diffraction low-passing, scattering, localization, externalization, and spatial Sound, generated by wave-based Propagation of directional sources and listener in complex scenarios. We also present results from our preliminary user study.
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SIVE@VR - Wave-based Sound Propagation for VR applications
2014 IEEE VR Workshop: Sonic Interaction in Virtual Environments (SIVE), 2014Co-Authors: Ravish Mehra, Dinesh ManochaAbstract:Realistic Sound effects are extremely important in VR to improve the sense of presence and immersion. They augment the visual sense of the user and can help reduce simulation fatigue. Sound can provide 3D spatial cues outside eld of view and help create high-fidelity VR training simulations. Current Sound Propagation techniques are based on heuristic approaches or simple line-of-sight based geometric techniques. These techniques cannot capture important Sound effects such as diffraction, interference, focusing. For VR applications, there is a need for high-fidelity, accurate Sound Propagation. In order to model Sound Propagation accurately, it is important to model wave-based Sound Propagation. We present a set of efficient wave-based Propagation techniques for VR applications that can handle large scenes, directional Sound sources, and generate spatial Sound. Our technique has been integrated in Valve's game engine and we use it to demonstrate realistic acoustic effects such as diffraction, high-order re ection, interference, directivity, and spatialization, in complex scenarios.
Vladimir E. Ostashev - One of the best experts on this subject based on the ideXlab platform.
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Equations for direct numerical simulation of Sound Propagation in a moving atmosphere
The Journal of the Acoustical Society of America, 2003Co-Authors: Vladimir E. Ostashev, D. Keith Wilson, Lanbo Liu, Mark L. Moran, David F. Aldridge, David H. MarlinAbstract:Most previous analytical and numerical studies of Sound Propagation in a moving atmosphere have been based on wave equations for the Sound pressure and on various parabolic approximations to the wave equations. However, these equations cannot be used as starting equations for recently proposed direct numerical simulation (DNS) of Sound Propagation outdoor since such starting equations should be first‐order differential equations with respect to time. In the present paper, we derive two closed sets of the first‐order differential equations for the Sound pressure and fluctuations in medium velocity and density due to a propagating Sound wave. These sets can be used as starting equations for DNS of Sound Propagation in a moving atmosphere. The ranges of applicability of these sets are studied by comparing them with the equations for the Sound pressure used previously. Note that both sets can also be employed for analytical studies of Sound Propagation in a moving atmosphere. Examples of the use of these sets...
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Sound Propagation and Scattering in Random Moving Media
Lecture Notes in Physics, 2002Co-Authors: Vladimir E. OstashevAbstract:This paper gives a handbook-type overviewof the theories of Sound Propagation and scattering in random moving media and the major phenomena known in this field.
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Development of the Modern Theory of Sound Propagation in the Turbulent Atmosphere
1998Co-Authors: G. H. Goedecke, Vladimir E. OstashevAbstract:Abstract : The foundations of the modern theory of Sound Propagation and scattering in a homogeneous and isotropic atmospheric turbulence are developed: The Sound scattering cross-section for von Karman spectra of temperature and wind velocity fluctuations is calculated; the rigouros theory of line of sight Sound Propagation in an atmosphere with Kolmogorov, Gaussian and von Karman spectra of temperature and wind velocity fluctuations is developed; a new theoretical formulation of the interference of the direct wave from source to receiver and that reflected from the ground in a turbulent atmosphere is presented; the Sound scattering cross section in an atmosphere with arbitrary profiles of temperature and wind velocity is calculated; some predictions of the modern theory are verified experimentally; correct wideangle parabolic equations for Sound waves in a turbulent atmosphere are derived and used for numerical simulations of Sound Propagation. The modern theory has already been adopted by scientists for calculations of Sound Propagation in turbulent media and as a basis for development of new acoustic remote sensing techniques of the atmosphere and ocean in several countries and organizations including the U.S. Army Research Laboratory.
Patrick J. Loughlin - One of the best experts on this subject based on the ideXlab platform.
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Local spectral and spatial frequency moments of shallow-water Sound Propagation
Advanced Signal Processing Algorithms Architectures and Implementations XII, 2002Co-Authors: Patrick J. LoughlinAbstract:Underwater Sound Propagation is inherently nonstationary, particularly in shallow water where the ocean surface and bottom act like waveguide boundaries, giving rise to structural (or geometric) dispersion. The spectrogram has been a principal means to study the nonstationarities and dispersion characteristics of shallow-water Sound Propagation. In this paper, we give the low-order conditional time-frequency moments of a wave propagating in a waveguide. Comparison of these results is made to spectrograms of explosive source Sound Propagation in the Yellow Sea.
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Time-frequency analysis and conditional moments of shallow-water Sound Propagation
The Journal of the Acoustical Society of America, 2002Co-Authors: Patrick J. LoughlinAbstract:Shallow‐water Sound Propagation is inherently nonstationary owing to such effects as geometric dispersion. The spectrogram has been a principal means to study the nonstationarities and dispersion characteristics of shallow‐water Sound Propagation. In this talk, we give the low‐order conditional spectral and wave number moments of Sound Propagation in dispersive environments, and show how they characterize the nonstationarities induced by channel dispersion on the propagating wave. [Work supported by ONR (N00014‐02‐1‐0084).]
Sujeong Kim - One of the best experts on this subject based on the ideXlab platform.
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source and listener directivity for interactive wave based Sound Propagation
IEEE Transactions on Visualization and Computer Graphics, 2014Co-Authors: Ravish Mehra, Lakulish Antani, Sujeong Kim, Dinesh ManochaAbstract:We present an approach to model dynamic, data-driven source and listener directivity for interactive wave-based Sound Propagation in virtual environments and computer games. Our directional source representation is expressed as a linear combination of elementary spherical harmonic (SH) sources. In the preprocessing stage, we precompute and encode the propagated Sound fields due to each SH source. At runtime, we perform the SH decomposition of the varying source directivity interactively and compute the total Sound field at the listener position as a weighted sum of precomputed SH Sound fields. We propose a novel plane-wave decomposition approach based on higher-order derivatives of the Sound field that enables dynamic HRTF-based listener directivity at runtime. We provide a generic framework to incorporate our source and listener directivity in any offline or online frequency-domain wave-based Sound Propagation algorithm. We have integrated our Sound Propagation system in Valve's Source game engine and use it to demonstrate realistic acoustic effects such as Sound amplification, diffraction low-passing, scattering, localization, externalization, and spatial Sound, generated by wave-based Propagation of directional sources and listener in complex scenarios. We also present results from our preliminary user study.