The probe and singular sources methods are well-known two classical direct reconstruction methods in inverse obstacle problems governed by partial differential equations. The common part of both methods is the notion of the indicator functions which are defined outside an unknown obstacle and blow up on the surface of the obstacle. However, their appearance is completely different. In this paper, by considering an inverse obstacle problem governed by the Laplace equation in a bounded domain as a prototype case, an integrated version of the probe and singular sources methods which fills the gap between their indicator functions is introduced. The main result is decomposed into three parts. First, the singular sources method combined with the probe method and notion of the Carleman function is formulated. Second, the indicator functions of both methods can be obtained as a result of decomposing a third indicator function into two ways. The third indicator function blows up on both the outer and obstacle surfaces. Third, the probe and singular sources methods are reformulated and it is shown that the indicator functions on which both reformulated methods based, completely coincide with each other. As a byproduct, it turns out that the reformulated singular sources method has also the Side B of the probe method, which is a characterization of the unknown obstacle by means of the blowing up property of an indicator sequence.
翻译:摘要:探测法与奇源法是偏微分方程控制的反障碍问题中两种经典的直接重构方法。这两种方法的共同点在于指示函数的概念——指示函数在未知障碍物外部定义,并在障碍物表面发生爆破。然而,两者的表现形式截然不同。本文以有界域内拉普拉斯方程控制的反障碍问题作为原型案例,引入了一种融合探测法与奇源法的集成版本,该版本填补了两种方法指示函数之间的理论空白。主要结果分解为三个部分。首先,构建了结合探测法概念与卡尔曼函数的奇源法公式化体系。其次,两种方法的指示函数均可通过对第三种指示函数进行两种不同方式分解而获得;该第三种指示函数在外部边界与障碍物表面均发生爆破。最后,对探测法与奇源法进行重构,证明这两种重构方法所依赖的指示函数完全一致。作为副产品,研究发现重构后的奇源法同样具备探测法的"B面"特性,即通过指示序列的爆破性质对未知障碍物进行刻画。