Abstract
Acoustical holography is being considered for quantitative studies of acoustic source distributions. We examine the quantitative significance of images reconstructed using the holographic technique described by R. L. Cohen in Pennsylvania State University Applied Research Laboratory Tech. Memo. 76-05, Jan 1976, for sources distributed over a plane surface. The image is formed by measuring the magnitude and phase of the sound pressure due to the sources on a parallel hologram plane and then calculating values of a Helmholtz integral of these pressures for field points located on the original source plane. Values of this integral form the reconstructed image. If the source and hologram planes are many wavelengths apart, this image represents a pressure distribution over the source plane which is nearly identical to the radiating, low wavenumber portion of the original pressure distribution on the source plane. The original pressure distribution may contain nonradiating high wavenumber components which are attenuated in the reconstructed image. To provide insight for understanding reconstructed images, the radiating portion of the pressure distribution is exhibited for point sources and for a finite circular membrane vibrating in an infinite rigid baffle. The radiating portions of these distributions differ considerably from the total pressure distribution for these sources.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
