Through-wall and wall microwave tomography imaging

Abstract

In the present work new results of experimental investigation on TWWI with using the microwave tomography technique are submitted. A tomographic algorithm is employed for the cross-section imaging of dielectric and metal objects on the other side of a concrete wall and within a concrete block. The cross-section restoration of studied objects is based on the tomography integral equation. The scattered field of the object is measured on a direct line parallel to the wall investigated. The solution of this integral equation gives the possibility to find the function representing the normalized polarization current distribution in the probing cross-section which is normal to the wall surface and in which the scan line lies (vertical cross-section). The normalized polarization current distribution depends on frequency and can be calculated for a set of frequencies. The image function is defined as modulus of the sum of the normalized polarization current distributions. If the wall material in vertical cross-section is not homogeneous because of the presence of defects or quests within the wall or on the other side of the wall, one can see these inhomogeneities. A set of images in different vertical cross-sections allows us to reconstruct a 3D image of the object. It is shown that advanced through-wall and wall images can be obtained by application of an indemnification procedure to the field caused by final sizes of the scanning line and also by using an algorithm allowing us to allocate from the complete field the scattering component.