Fundamentals of Acoustic Field Theory and Space-Time Signal Processing

Ziomek, Lawrence J.

doi:10.1201/9781003069317

Cited by 62 publications

(10 citation statements)

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“…is a distance-related attenuation assuming spherical propagation [56], and c is the sound propagation velocity in air.…”

Section: Notation and Problem Statementmentioning

confidence: 99%

Audiovisual Tracking of Multiple Speakers in Smart Spaces

Sanabria-Macias,

Marron-Romera,

Macias-Guarasa

2023

Sensors

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This paper presents GAVT, a highly accurate audiovisual 3D tracking system based on particle filters and a probabilistic framework, employing a single camera and a microphone array. Our first contribution is a complex visual appearance model that accurately locates the speaker’s mouth. It transforms a Viola & Jones face detector classifier kernel into a likelihood estimator, leveraging knowledge from multiple classifiers trained for different face poses. Additionally, we propose a mechanism to handle occlusions based on the new likelihood’s dispersion. The audio localization proposal utilizes a probabilistic steered response power, representing cross-correlation functions as Gaussian mixture models. Moreover, to prevent tracker interference, we introduce a novel mechanism for associating Gaussians with speakers. The evaluation is carried out using the AV16.3 and CAV3D databases for Single- and Multiple-Object Tracking tasks (SOT and MOT, respectively). GAVT significantly improves the localization performance over audio-only and video-only modalities, with up to 50.3% average relative improvement in 3D when compared with the video-only modality. When compared to the state of the art, our audiovisual system achieves up to 69.7% average relative improvement for the SOT and MOT tasks in the AV16.3 dataset (2D comparison), and up to 18.1% average relative improvement in the MOT task for the CAV3D dataset (3D comparison).

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“…is a distance-related attenuation assuming spherical propagation [56], and c is the sound propagation velocity in air.…”

Section: Notation and Problem Statementmentioning

confidence: 99%

Audiovisual Tracking of Multiple Speakers in Smart Spaces

Sanabria-Macias,

Marron-Romera,

Macias-Guarasa

2023

Sensors

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“…Arrays of acoustic sources that are closely spaced relative to the upper wavelength of operation can produce a highly controllable radiation aperture. A variety of useful designs have appeared over the years, many well before the current period of readily available components including fixed passive designs 1,2 and actively steered examples 3,4,5 . To achieve a radiation pattern that is free of unwanted artefacts generally imposes constraints on the spacing 6 of the transducers and therefore, the size of the transducers limits the available SPL. Some interesting schemes to mitigate these artefacts have been found 7 , yet for high SPL or full-range reproduction, such systems are often inadequate.…”

Section: 'Broadside' Aperture Type Arraysmentioning

confidence: 99%

Hybrid Line Arrays - A Viable Alternative

THOMPSON,

LEEMBRUGGEN,

GILFILLAN

2023

Reproduced Sound 2009

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In this paper we investigate a hyrbid combination of a high frequency horn and a steered end-fire array loudspeaker. After a brief review of established line array methods we describe the hybrid line array and the advantages of this combination. We then explain how numerical optimisation can be applied to the hybrid array to determine the elemental transfer functions that can optimise the system to meet user requirements. The performance of this system is analysed and its limitations discussed. Finally we suggest some areas where more investigation is required. ESTABLISHED METHODS OF RADIATION CONTROL HornsAside from relying on the size of a direct radiator, horns offer the simplest of all methods to control radiation pattern. Constant or differential-dispersion horns are commonplace, well understood and can be produced relatively cheaply. However, when the mouth size is small compared to the radiated wavelength, the device behaves more like a simple source, thus losing the ability to control its radiation pattern. With increasing frequency, the horn becomes acoustically larger and enters the region of effective pattern control. At the highest frequencies, increasingly smaller regions concentrated at the throat have most influence on the output.

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“…12, b fills the gap, understandable from further discussion. The artifact of amplitude loss points to or allows deducing the interface being a typical energy release defect with the meanings of axis of phenomenological thermo-mechanical conversion comparable to minimization of entropy, where mathematical implications for further understanding are available in [41]. The excessive energy loss possibly may include such contributions as more physical aspects and causes of immiscibility in nature, such as slip and, squeeze and collision associated with "fluid bodies" of miniscule dimensions whether integrating with or disintegrating from the interface.…”

Section: Fig 11 P-and S-wave Velocity Variation For All Tests: a -P-w...mentioning

confidence: 99%

Viability assessment of integrated P- and S-wave surveys using ultrasound

Hassan

2022

jour

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Potential of, integrated geophysical, especially P- and S-wave combined near surface surveys, is assessed; demonstrated with use of sparingly, reduced chronographic i. e., time and velocity, (1 MHz) ultrasonic imaged data. Case of aqueous and non-aqueous, predominantly, fossil fuel origins spills seepage within near-surface geology is examined in terms of evaluation of possible complexities of fluids and surrounding interactions; which are experimentally simulated embodied as flow components of an immiscible displacement process. Such processes are understood and studied widely, within various, especially near-field geo- and engineering including environmental and also geo-disaster contexts. Interesting relevant scenarios, including aspects, of geological complexity of well known geographical locations while their subjugation also to various, whether natural or anthropogenic, stressors are presented alongside pertinent theory for better grasp, including plausibility, of methodology and inferring. Experimental analogues and geometrical constraints are explained in detail. Ultrasonic P- and S-wave, data in relevant context, also verified analytically, are comprehensively evaluated. S-wave data not only corroborates P-wave data attributes in time-space localization of displaced, from displacing phase, including a “dim spot”, an interesting artifact corresponding to interface (or mixed phase) region, S-wave also manifested other elastic and thermo-mechanical characteristics of the same feature. Further a flow rate, especially, that of injection, control or dependence of a planned displacement process was confirmed, for example if required in tracer and remedial studies. S-waves characteristic suitability to reveal other fluid-fluid and fluid-solid interaction peculiarities at micro and possibly at nano scale, as amplitude effects, is foreseen to assume significant promise.

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Fundamentals of Acoustic Field Theory and Space-Time Signal Processing

Cited by 62 publications

References 0 publications

Audiovisual Tracking of Multiple Speakers in Smart Spaces

Audiovisual Tracking of Multiple Speakers in Smart Spaces

Hybrid Line Arrays - A Viable Alternative

Viability assessment of integrated P- and S-wave surveys using ultrasound

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