SCANNING TOMOGRAPHIC ACOUSTIC MICROSCOPY WITH MULTIPLE TRANSDUCERS AND FREQUENCIES

Abstract
The scanning tomographic acoustic microscope (STAM) is an instrument that utilizes the principles of diffraction tomography and acoustical holography to produce unambiguous subsurface images of structurally complex objects. One of the several techniques to obtain projection data is to rotate the transducer and another, to rotate the specimen. In either case a small unknown movement out of register will cause phase errors which can severely degrade the tomograms. A third technique uses a multiplicity of fixed transducers and frequencies. Our simulation studies show that this technique is capable of producing the best images because it is entirely free of either transducer or specimen movement.