Módszerek összehasonlítása

	Akusztikus holográfia	Gerendafókuszálás	BEM Akusztika
Tudományterület	Akusztika	Akusztika	Akusztika
Módszercsalád	Process / pipeline	Process / pipeline	Process / pipeline
Keletkezés éve	1985	1988	1971
Megalkotó	James Maynard, Earl Williams, Yongjian Lee	Van Veen, Barry Buckley	Carlos Brebbia, Robert Butterfield
Típus	Sound field reconstruction method	Directional audio array processing	Computational simulation for acoustics
Alapmű	Maynard, J. D., Williams, E. G., & Lee, Y. (1985). Near-field acoustic holography: I. Theory of generalized holography and the development of NAH. Journal of the Acoustical Society of America, 78(4), 1395–1413.	Van Veen, B. D., & Buckley, K. M. (1988). Beamforming: A versatile approach to spatial filtering. IEEE ASSP Magazine, 5(2), 4–24.	Burton, A. J., & Miller, G. F. (1971). The application of integral equation methods to the numerical solution of some exterior boundary-value problems. Proceedings of the Royal Society A, 323(1553), 201–210.
Alternatív nevek	NAH, near-field acoustics, sound field mapping, acoustic imaging	beamformer, spatial filtering, microphone array, phased array	BEM, boundary element method, indirect BEM, direct BEM
Kapcsolódó	5	5	5
Összefoglaló	Near-Field Acoustic Holography (NAH) is a technique for reconstructing 3D acoustic sound fields and visualizing sound radiation from sources by measuring pressure at a dense microphone array in the near field. Pioneered by Maynard, Williams, and Lee in 1985, NAH extends holographic principles from optics to acoustics, enabling detailed acoustic source characterization, noise source identification, and acoustic field visualization that is impossible with conventional single-point or line-array methods.	Beamforming is a spatial signal processing technique that uses microphone arrays to selectively enhance sound from a desired direction while suppressing sounds from other directions. Formalized by Van Veen and Buckley in 1988, beamforming is fundamental to hands-free speech communication, hearing aids, sonar, radar, and spatial audio recording. It enables 'listening' with directional sensitivity despite using omnidirectional microphones, by exploiting time delays and phase differences between array elements.	The Boundary Element Method (BEM) is a numerical technique for solving acoustic wave equations in complex geometries. Unlike finite element methods (FEM) that mesh entire volumes, BEM discretizes only the acoustic boundaries (surfaces), reducing computational cost and memory. First applied to acoustics by Burton and Miller in 1971, BEM is widely used for predicting room acoustics, exterior noise radiation, and acoustic scattering without the need for volumetric meshing.