Terahertz wave imaging using time domain iterative shrink threshold method

Abstract

Abstract We propose a new linear imaging method that combines the iterative shrinkage thresholding algorithm (ISTA) with the synthetic aperture (SA) method to achieve high resolution. Unlike other ISTA methods that use a single frequency component of signals, we use time domain signals directly as measurement, which allows for simultaneous wide bandwidth calculation and potentially better imaging results. Additionally, we simplify the backward estimation process by using impulse back-projection based on the SA method, which reduces the computing cost compared to the ISTA method. Numerical simulation and experimental measurement results show that the image resolution is similar to that of our previous non-linear imaging method, and two reflectors with different reflectivity are imaged linearly. These comparison results demonstrate the effectiveness of our proposed method in achieving high-resolution and maintaining the linearity of target reflectivity.