手法を比較

	音響ホログラフィ	音線追跡（Acoustic Ray Tracing）	Beamforming
分野	音響学	音響学	音響学
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1985	1979	1988
提唱者	James Maynard, Earl Williams, Yongjian Lee	James Allen, David Berkley	Van Veen, Barry Buckley
種類	Sound field reconstruction method	Computational room acoustics method	Directional audio array processing
原典	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.	Allen, J. B., & Berkley, D. A. (1979). Image method for efficiently simulating small-room acoustics. Journal of the Acoustical Society of America, 65(4), 943–950.	Van Veen, B. D., & Buckley, K. M. (1988). Beamforming: A versatile approach to spatial filtering. IEEE ASSP Magazine, 5(2), 4–24.
別名	NAH, near-field acoustics, sound field mapping, acoustic imaging	ray tracing, geometric acoustics, image source method, sound ray propagation	beamformer, spatial filtering, microphone array, phased array
関連	5	5	5
概要	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.	Acoustic ray tracing is a computational technique for predicting sound propagation in rooms by treating acoustic energy as rays that reflect specularly off surfaces. Formalized by Allen and Berkley in 1979 via the image source method, ray tracing is one of the most computationally efficient methods for room acoustic simulation, especially for early and mid-reflections. It is widely used in audio engineering, architectural acoustics, and interactive spatial audio for virtual environments.	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.