Simulation tools for through wall imaging

• Main Author: Cheng, Kaixuan
• Other Authors: Abdulkadir C. Yucel
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/154359
• Institution: Nanyang Technological University

Through wall imaging (TWI) via electromagnetic signals has recently received significant attention due to its potential applications, which include rescuing humans from collapsed buildings, detecting the human activity inside buildings, detecting dangerous goods during transportation, and non-destructive testing. In the context of TWI, this thesis focuses on the development of a forward solver to be used in the iterative process of the TWI. In particular, the solver is based on a 2-D volume integral equation derived, assuming that the fields sent to interrogate the region of interest (RoI) lying on xy plane are transverse magnetic to the z-axis. The solver takes the permittivity map of the RoI partitioned with cells as input. After discretizing the polarization currents on cells via pulse basis functions and applying the point-matching, the solver iteratively solves the linear system of equation arising from the discretization. During the iterative solution, each matrix-vector multiplication is accelerated by the fast Fourier transform (FFT). The solver outputs the polarization currents as well as the incident, scattered, and total fields on each cell. During the iterative full-wave TWI inversion process, the developed solver will be extensively executed to obtain the field values corresponding to the trial permittivity maps. These field values will be compared with the actual field values obtained by the measurements to arrive at the actual permittivity map of RoI in the inversion process.