期刊
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
卷 111, 期 1, 页码 53-63出版社
ACOUSTICAL SOC AMER AMER INST PHYSICS
DOI: 10.1121/1.1421344
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资金
- NCI NIH HHS [CA 74050, CA 81688] Funding Source: Medline
- NHLBI NIH HHS [HL 50855] Funding Source: Medline
- NATIONAL CANCER INSTITUTE [R01CA074050, R29CA081688] Funding Source: NIH RePORTER
- NATIONAL HEART, LUNG, AND BLOOD INSTITUTE [R01HL050855] Funding Source: NIH RePORTER
A k-space method for large-scale simulation of ultrasonic pulse propagation is presented. The present method, which solves the coupled first-order differential equations for wave propagation in inhomogeneous media, is derived in a simple form analogous to previous finite-difference methods with staggered spatial and temporal grids. Like k-space methods based on second-order wave equations, the present method is exact for homogeneous media, unconditionally stable for slow [c(r)less than or equal toc(0)] media, and highly accurate for general weakly scattering media. In addition, unlike previous k-space methods, the form of the method allows straightforward inclusion of relaxation absorption and perfectly matched layer (PML) nonreflecting boundary conditions. Numerical examples illustrate the capabilities of the present k-space method. For weakly inhomogeneous media, accurate results are obtained using coarser temporal and spatial steps than possible with comparable finite-difference and pseudospectral methods. The low dispersion of the k-space method allows accurate representation of frequency-dependent attenuation and phase velocity associated with relaxation absorption. A technique for reduction of Gibbs phenomenon artifacts, in which compressibility and exponentially scaled density functions are smoothed by half-band filtering, is introduced. When employed together with this smoothing technique, the k-space method provides high accuracy for media including discontinuities, high-contrast inhomogeneities, and scattering structures smaller than the spatial grid resolution. (C) 2002 Acoustical Society of America.
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