Dept. of Biophys. & Electron. Eng., Genoa Univ.
IEEE Trans Med Imaging. 1993;12(2):232-9. doi: 10.1109/42.232251.
A numerical method for microwave imaging of two-dimensional inhomogeneous biological bodies illuminated by TM waves is presented. It is a spatial-domain multiview approach which makes use of the moment method to discretize the integral-equation formulation of inverse scattering. A pseudoinversion technique is applied to obtain a minimum-norm solution for the equivalent current density inside the cross-section of a scatterer. A multi-illumination-angle multiview process is used. The invariance of the Green matrix makes it possible to perform only one pseudoinverse (off line and once for all), independently of the number of views, thus reducing the need for computer resources. A pixel representation is adopted, and a look-up table is utilized to fast synthesize images. No plane-wave illumination is required and no first-order approximations are applied. Distortions in the dielectric reconstruction and noise effects are evaluated via some numerical simulations.
提出了一种用 TM 波对二维非均匀生物物体进行微波成像的数值方法。这是一种基于空域的多视角方法,利用矩量法对逆散射积分方程进行离散化。应用伪逆技术获得了散射器横截面上等效电流密度的最小范数解。采用多照明角度多视角处理。格林矩阵的不变性使得只需要进行一次伪逆(离线且一次完成),与视角数量无关,从而减少了对计算机资源的需求。采用像素表示,并利用查找表快速合成图像。不需要平面波照明,也不应用一阶近似。通过一些数值模拟评估了介电重建中的失真和噪声影响。