Journal•ISSN: 0018-9537
IEEE Transactions on Sonics and Ultrasonics
Institute of Electrical and Electronics Engineers
About: IEEE Transactions on Sonics and Ultrasonics is an academic journal. The journal publishes majorly in the area(s): Surface acoustic wave & Acoustic wave. It has an ISSN identifier of 0018-9537. Over the lifetime, 960 publications have been published receiving 27973 citations.
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TL;DR: In this article, the authors derived autocorrelation functions and power spectra derived from B-scans of a scattering phantom containing many scatterers per resolution cell, leading naturally to the definition of the average speckle spot or cell sue, and this inturn is comparable to the resolution cell.
Abstract: the of the magnitude, i.e., intensity, of the field.) It is shown that Rayleigh statistics govern the fist-order behavior of the magnitude; and the autocorrelation of the resulting image speckle is obtained by the methodof Middleton. The corresponding power spectrum follows immediately by Fourier transformation. Theoretical and experimentally determined autocorrelation functions and power spectra derived from B-scans of a scattering phantom containing many scatterers per resolution cell are presented. These functions lead naturally to the definition of the average speckle spot or cell sue, and this inturn is comparable to the resolution cell. Each independent speckle servesas a degreeof freedom that determines the number of samples of tissue available over a target.As the speckle cell size decreases this number increases in a manner predictable from the physical parameters of the cell size. However, it is found that the speckle cellis broadened, the degrees of freedom diminished, when the object structureis correlated. This yields the possibilityof deducing information about the object structure from the second-order statistics of the speckle texture, in addition to that obtainable from the fiistorder statistics.
1,449 citations
TL;DR: In this paper, the reduction in speckle that can be obtained with a compound scan with maximum amplitude writing is computed and the condition for the independence of two amplitude values is derived.
Abstract: Ultrasound images obtained with a simple linear or sector scan show a granular appearance, called "speckle." This speckle is analyzed. The reduction in speckle that can be obtained with a compound scan with maximum amplitude writing is computed. The reduction in speckle is almost as large as can be obtained with averaging. It depends on the number of independent amplitude values that are measured. The condition for the independence of two amplitude values is derived, and thus a limit is given for the possible reduction in speckle.
1,096 citations
TL;DR: In this article, a criterion for judging the relative effeciency of excitation of piezoelectric surface waves as a function of crystal plate orientation and propagation direction is developed based on a velocity change upon application of a thin conducting sheet to the surface.
Abstract: A criterion for judging the relative effeciency of excitation of piezoelectric surface waves as a function of crystal plate orientation and propagation direction is developed. This criterion is based on a velocity change upon application of a thin conducting sheet to the surface. Plots of surface wave velocity for various orientations of the crystal surface are presented as a function of propagation direction for the conducting sheet in contact with and infinitely far removed from the crystal surface. A plot of a typical velocity variation as a function of height of the conducting sheet is also presented. Evidence in support of the criterion of using velocity changes as an indicator of efficiency is presented in the form of mechanical displacement and electric potential plots for several orientations and propagation directions. All velocity displacements and potential calculations were carried out under the assumption that the crystal medium was lithium niobate.
641 citations
TL;DR: In this article, a nouvelle methode de caracterisation tres precise des materiaux is proposed, in which the caracteristiques de propagation des ondes de fuite a la limite entre l'eau et l'echantillon; the vitesse de phase and l'attenuation sont determinees a travers des mesures de la courbe V(z).
Abstract: On propose une nouvelle methode de caracterisation tres precise des materiaux. On mesure les caracteristiques de propagation des ondes de fuite a la limite entre l'eau et l'echantillon; la vitesse de phase et l'attenuation sont determinees a travers des mesures de la courbe V(z). On presente une methode d'analyse spectrale pour obtenir les proprietes acoustiques a partir des courbes V(z). Description des mesures effectuees en utilisant des materiaux isotropes ou anisotropes pour lesquels les vitesses s'etendent de 2000 a 11000 m/s. On examine tous les modes d'ondes de fuite impliques dans les phenomenes d'interferences dans les courbes V(z). Resultats experimentaux confirmant les resultats theoriques. Application a l'analyse de la structure des materiaux polycristallins
536 citations
502 citations