Ultrasonic imaging of an object at the presence of Fourier and non-Fourier transformation in the transmitted through the object acoustic field.
ABSTRACT A metal object is computer visualized by registration of the amplitudes of the transmitted through the object short acoustic pulses. The pulses are separated by time, because of the presence of holes and internal compact components in the longitudinal section (structure along the propagation direction of acoustic wave). The acoustic field transmitted through the object is composited from a field presenting Fourier transformation of the hole shape and field, transmitted through the metal components in the longitudinal section of the object. A computer Fourier transformation of the digital data of the amplitude fields transmitted through the object components is performed instead of converging lens. The Fourier series of the object obtained as digital data after the transformation is multiplied with a term, describing the angle distribution of the field on spatial frequencies. The reconstruction of the image of the metal components is performed by reverse transformation, i.e. summing up in all spatial frequencies. 3D visualization of the transmitted through the hole acoustic field determines the hole geometry (circular, square, rectangular). It is shown that at the transmission of a short acoustic pulse through the components with different thicknesses and holes, presenting Fourier and non-Fourier transformation can be registered separately in contrast to the optics.
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ABSTRACT: Ultrasonic three-dimensional images are constructed by stacking B-scan tomograms or ultrasonic CAT scans with a computer algorithm for subsequent perspective or sectional display. Perspective images of surfaces representing Doppler measurements of fluid velocity are illustrated in combination with isovelocity contours for flows through a flexible tube in vitro. Isospeed contours calculated from a dynamically moving epicardial surface are mapped onto the heart surface illustrating the combination of quantitative parametric data with a qualitative surface display. The efficacy of three-dimensional displays for increasing the information density and comprehensibility of pictoral representations of ultrasonic data sets is discussed.Journal of Medical Systems 01/1983; 6(6):579-89. · 1.78 Impact Factor
Chapter: Introduction to Fourier optics2 01/1995; Roberts and Company Publishers., ISBN: 0070242542