Current distribution cAlculations

Antenna design and simulations

Sensor modeling

RCS & Bi-RCS computations

Current distributions on metallic plates

Inverse scattering simulations

Radargrams of buried pipes

Experimental inverse scattering

Borehole measurements

ScaleME

Inverse Scattering Reconstructions

The Electromagnetics Laboratory has had a long history in the area of inverse scattering research for about 10 years now. In the 1990, we came up we an iterative inverse scattering scheme, the Distorted Born Iterative method (DBIM), which allowed us to perform the reconstruction of highly contrasted bodies, more specifically in time-domain. This numerical scheme was reveiled almost at the same period as a similar one, developped in Supelec, France, known as the Newton-Kantorovich method, more specifically aimed towards frequency-domain reconstructions. Later on, further studies proved that these two schemes were equivalent. So far, these two technique still represent the state of the art in iterative inverse scattering for complex and highly contrasted inhomogeneous bodies.

For further readings about DBIM, go to Prof. Weng Cho Chew's publication page or download the following paper: W.C. Chew, G.P. Otto, W.H. Weedon, J.H. Lin, C.C. Lu, Y.M. Wang, and M.Moghaddam, "Nonlinear Diffraction Tomography-The Use of Inverse Scattering for Imaging," Int. J. Imaging Sys. Tech., vol. 7, pp. 16-24, 1996. (compressed file using the "compress" command on UNIX, hold down the shift key while clicking here).

In the following, we present the result of the experimental reconstruction from measurement data gathered with our in-house experimental system, more thoroughly described here.

Reconstruction of a hollow PVC pipe (4.8cm in outer diameter, 3.7cm in innner diameter)

PVC pipe permittivity distribution at the 1st iteration

PVC pipe permittivity distribution at the 5th iteration

PVC pipe permittivity distribution at the 10th iteration

PVC pipe permittivity distribution at the 20th iteration

PVC pipe permittivity distribution at the 30th iteration

PVC pipe permittivity distribution at the 40th iteration

PVC pipe permittivity distribution at the 50th iteration

PVC pipe permittivity distribution at the 60th iteration

Reconstruction of two plastic rods (2cm in diameter and separated by 2.5mm)

The above work is a collaboration between Dr. FuChiarng Chen and Prof. Weng Cho Chew. We also would like to thank former students who developped and participated actively in this area: Olivier Franza, Hong Gan, Guy Klemens, Jiun-Hwa Lin, Qing-Huo Liu, and Dr. William Weedon. Please send suggestions, comments, and inquiries to: fchen@sunchew.ece.uiuc.edu.