Real Time Acoustical Imaging by Means of Liquid Surface Holography

Abstract

The techniques of liquid surface acoustical holography have proven to be very effective and useful in applications to industrial testing and biomedical imaging. The most useful images have been produced by focused image techniques, that is, by using acoustic lenses to focus the image into the hologram. Because liquid surface holography has usually been illustrated by use of images focused into the hologram, there has been an erroneous but growing belief that liquid surfaces are not effective in forming true holograms capable of imaging outside the hologram plane. Although published papers (1,2,3) provide evidence that this belief is incorrect, further evidence at this time may be useful and will be presented in this paper.