公开(公告)号：US06411095B1

公开(公告)日：2002-06-25

申请号：US09305718

申请日：1999-05-05

申请人： Daniel C. Chin ,  Rengaswamy Srinivasan ,  Paul R. Zarriello

发明人： Daniel C. Chin ,  Rengaswamy Srinivasan ,  Paul R. Zarriello

IPC分类号： G01V308

CPC分类号： G01V3/06

摘要： The invention is directed to an apparatus and method for locating objects in a body through the mapping and imaging of the conductivity profiles of such objects by applying a force to the object and/or body and measuring certain characteristics of the body responsive to the application of force. In accordance with a preferred embodiment, the force applied to the object and body is in the form of an electrical voltage or current such that electrical potentials, currents, and magnetic fields are generated throughout the subsurface site. The voltage, current, or magnetic field is then measured at the surface or the boundary of the body. An estimate of subsurface conductivity is then made and a conductivity profile generated by minimizing a loss function. Preferably, the loss function is in the form of the sum square of the differences between measurement values and a set of computed values based on a gradient approximation technique. In a preferred embodiment, the approximation technique is a simultaneous perturbation stochastic approximation (SPSA). To characterize the object within the body, a conductivity profile is then constructed using a numerical technique such as a finite element method (FEM) to compute the potentials or magnetic fields along with the experimental values measured at the boundary of the site. The characterization of the object includes its location, size, and conductivity.

摘要翻译： 本发明涉及一种用于通过对物体和/或身体施加力并对身体的某些特征进行映射和成像来映射和成像身体中的物体的装置和方法，该装置和方法响应于应用 力。 根据优选实施例，施加到物体和身体的力是电压或电流的形式，使得在整个地下部位产生电势，电流和磁场。 然后在身体的表面或边界处测量电压，电流或磁场。 然后进行地下电导率的估计，并通过最小化损失函数产生电导率分布图。 优选地，损失函数是基于梯度近似技术的测量值与一组计算值之间的差的总和的形式。 在优选实施例中，近似技术是同时扰动随机近似（SPSA）。 为了表征体内的物体，然后使用诸如有限元法（FEM）的数值技术构造电导率分布，以计算电位或磁场以及在场地边界处测量的实验值。 对象的表征包括其位置，大小和电导率。