NEAR-SURFACE LOCALIZATION AND SHAPE IDENTIFICATION OF A SCATTERER EMBEDDED IN A HALFPLANE USING SCALAR WAVES
NEAR-SURFACE LOCALIZATION AND SHAPE IDENTIFICATION OF A SCATTERER EMBEDDED IN A HALFPLANE USING SCALAR WAVES
复制标题
使用标量波对嵌入半平面的散射体进行近表面定位和形状识别
DOI：
10.1142/s0218396x09003963
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发表时间：
2009
影响因子：
--
通讯作者：
L. Kallivokas
中科院分区：
文献类型：
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作者：
C. Jeong;Nam Seong;L. Kallivokas
我们讨论的逆问题与识别的散射体的位置和形状完全嵌入在一个均匀的半平面，使用很少的surprise测量其响应探测标量波。典型的应用出现在剪切（SH）波（反平面运动）下的土壤中，或在压力波下的声学流体中。因此，我们使用的狄利克雷型（位移），或诺依曼型（流体速度）的测量，以引导定位和检测过程，分别针对刚性和声音硬的对象。定位单个目标的计算方法是基于偏微分方程约束优化思想，扩展我们最近的工作从全1到半平面的情况下。为了提高优化器收敛到真实形状和位置的能力，我们采用了基于幅度的失配泛函，并将反演过程嵌入到频率和方向性连续方案中，这似乎可以减轻解的多重性。我们使用的设备的总微分来解决的目标的形状参数，一个LA的反演迭代过程中不断变化的形状。2，3我们报告的数值结果背叛算法的鲁棒性的SH和声学的情况下，和各种目标，从圆形和椭圆形，土豆，风筝形的散射体。
We discuss the inverse problem associated with the identification of the location and shape of a scatterer fully embedded in a homogeneous halfplane, using scant surficial measurements of its response to probing scalar waves. The typical applications arise in soils under shear (SH) waves (antiplane motion), or in acoustic fluids under pressure waves. Accordingly, we use measurements of either the Dirichlet-type (displacements), or of the Neumann-type (fluid velocities), to steer the localization and detection processes, targeting rigid and sound-hard objects, respectively. The computational approach for localizing single targets is based on partial-differential-equation-constrained optimization ideas, extending our recent work from the full-1 to the half-plane case. To improve on the ability of the optimizer to converge to the true shape and location we employ an amplitude-based misfit functional, and embed the inversion process within a frequency- and directionality-continuation scheme, which seem to alleviate solution multiplicity. We use the apparatus of total differentiation to resolve the target's evolving shape during inversion iterations over the shape parameters, a la.2,3 We report numerical results betraying algorithmic robustness for both the SH and acoustic cases, and for a variety of targets, ranging from circular and elliptical, to potato-, and kite-shaped scatterers.