Diffraction culling for virtual-acoustic simulations.

Calamia, Paul; Markham, Benjamin; Svensson, U. Peter

doi:10.1121/1.4783825

Cited by 5 publications

(3 citation statements)

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“…When all such edges are known, they can be considered as edge sources. The secondary source approach by Svensson et al was applied to room acoustical geometries, 70,[144][145][146] whereas the computationally more efficient but less accurate UTD formulation has been employed for complex geometries. 139,147 Subsequent developments presented the efficient implementation of secondorder diffraction to facilitate complex geometries.…”

Section: Diffraction Modeling In Ray Tracing and Image-source Methodsmentioning

confidence: 99%

Overview of geometrical room acoustic modeling techniques

Savioja¹,

Svensson

2015

The Journal of the Acoustical Society of America

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301

190

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Computerized room acoustics modeling has been practiced for almost 50 years up to date. These modeling techniques play an important role in room acoustic design nowadays, often including auralization, but can also help in the construction of virtual environments for such applications as computer games, cognitive research, and training. This overview describes the main principles, landmarks in the development, and state-of-the-art for techniques that are based on geometrical acoustics principles. A focus is given to their capabilities to model the different aspects of sound propagation: specular vs diffuse reflections, and diffraction.

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Section: Diffraction Modeling In Ray Tracing and Image-source Methodsmentioning

confidence: 99%

Overview of geometrical room acoustic modeling techniques

Savioja¹,

Svensson

2015

The Journal of the Acoustical Society of America

Self Cite

301

190

View full text Add to dashboard Cite

show abstract

“…It is mentioned that the BT formulation and the Medwin extension expose singularities, for example, at the values of initial arrival time [CK88; SFV99; TSK01] and in the vicinity of transitions zones [SC06;Cal09]. As has been pointed out earlier, continuity of the sound field is imperative for perception-appropriate dynamic auralisation.…”

Section: Acoustic Diffraction Modelsmentioning

confidence: 98%

Real-Time Auralisation of Outdoor Sound Propagation

Stienen¹

2023

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Auralisation describes the process of generating and presenting audible sound using computer programs and audio hardware. Since the result is perceived naturally by the human's auditory system, a demonstration by means of auralisation is easily comprehensible and does neither require background knowledge nor expertise. Producing auralisation under real-time constraints increases the implementation demands significantly. Real-time auralisation is required in applications that respond to user interaction, for example, in interactive Virtual Reality (VR) environments. Dynamically moving sound sources and receivers evoke a change in the perceived sound, and the corresponding result must be provided as quickly as possible. A feeling of immersion can be created if the response time of the system does not exceed perceptual thresholds and thus enables a plausible scene presentation. To achieve this emotional state, real-time auralisation must comply with the expected physical behavior. Because auralisation has gained much attention in room acoustics, the established concepts and approaches are insufficient, if applied to outdoor scenarios. This is due to the fact that simulation principles based on Geometrical Acoustics (GA) can determine specular sound reflection with ease, but only rudimentarily incorporate the contribution of diffracted sound. Nonetheless, the transmission of sound from a source to a receiver in an urban setting contains a significant contribution of reflected and diffracted components. Furthermore, highly dynamic virtual environments are time-variant. Traditional realisations neglect this characteristic, treating an acoustic environment as temporarily static on a frame-by-frame basis. Adaption to dynamic events is implemented by update routines performing sequences of time-invariant simulations, which is contradictory to the highly dynamic nature of outdoor scenarios. This misconception is addressed in this dissertation and an alternative solution is suggested. The realisation of a real-time auralisation application for outdoor environments represents a promising addition to current noise assessment procedures. It also delivers the foundation for auditory modality in VR regarding outdoor scenarios, serving as an audio-video tool for scientific investigations of urban sound environments, accounting for perceptual aspects. der PDs und die Zuordnung individueller Wellenfronten basiert auf einer Winkeldistanzmetrik ("k-means clustering") und die Korrektur der ITD berücksichtigt die Abweichungen im Azimut. Die Machbarkeit des vorgeschlagenen Echtzeit-Auralisierungssystems und die Eignung für die Schallausbreitung im Freien werden in einer interaktiven Applikation demonstriert, die auf VR-Technologien basiert.For the young who are inspiring me, the old who ground me and my dearest who holds everything together.

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“…Factors that constrain the accuracy include the inability of the standard algorithm to include boundary scattering or diffraction (the latter being zero in a rectangular or cuboid domain). These must be added on as additional processes [3,4]. But it's main constraining factor is its exponential computational cost scaling with reflection order.…”

Section: Introductionmentioning

confidence: 99%

Raytracing in Galerkin Boundary Integral form

McGee

Hargreaves

2023

inter noise

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Ray tracing is an established method for computing the late-time part of room impulse responses. But it has the drawback that only very crude Monte Carlo models of boundary scattering and diffraction are possible to include without losing its attractive computational cost scaling. This happens because higher-resolution models of these processes output multiple child rays for every parent ray received, making the number of rays grow with reflection order. An emerging solution is so-called 'Surface-Based' Geometrical Acoustics. Here the distribution of rays arriving at a boundary is mapped onto a predefined set of spatial elements and angular interpolation functions, producing a vector of coefficients. Re-radiation of subsequent reflections is then a matrix multiplication, with the steady state solution being solvable via a Neumann series. Since rays only every propagate one reflection order before being collected, diffraction and scattering process that cause them to multiply can be included without issue. Here we present a new formulation based on a Galerkin Boundary Element Method (BEM). A unique feature is its ability to readily change interpolation functions, so their effect on accuracy and convergence can be assessed. In this preliminary work, it is verified against an Image Source Model for a rectangular room.

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Diffraction culling for virtual-acoustic simulations.

Cited by 5 publications

References 0 publications

Overview of geometrical room acoustic modeling techniques

Overview of geometrical room acoustic modeling techniques

Real-Time Auralisation of Outdoor Sound Propagation

Raytracing in Galerkin Boundary Integral form

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