เปรียบเทียบวิธี

	Acoustic Holography	Beamforming	ท่อวัดอิมพีแดนซ์
สาขาวิชา	สวนศาสตร์	สวนศาสตร์	สวนศาสตร์
ตระกูล	Process / pipeline	Process / pipeline	Process / pipeline
ปีกำเนิด	1985	1988	1866
ผู้ริเริ่ม	James Maynard, Earl Williams, Yongjian Lee	Van Veen, Barry Buckley	August Kundt
ประเภท	Sound field reconstruction method	Directional audio array processing	Acoustic absorption measurement
แหล่งต้นตำรับ	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.	ASTM E1050-19 (2019). Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube, Two Microphone and a Digital Frequency Analysis System. American Society for Testing and Materials.
ชื่อเรียกอื่น	NAH, near-field acoustics, sound field mapping, acoustic imaging	beamformer, spatial filtering, microphone array, phased array	kundt tube, resonance tube, acoustic absorption, sound absorption coefficient
ที่เกี่ยวข้อง	5	5	5
สรุป	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.	An impedance tube (or Kundt tube) is a laboratory apparatus for measuring the acoustic absorption coefficient and surface impedance of materials. Originally developed by August Kundt in 1866, the technique has been standardized by ASTM and ISO for characterizing noise-control and acoustic-treatment materials. The impedance tube method is simple, portable, and cost-effective, making it the industry standard for pre-design acoustic material selection and quality control.