An Imaging Enhancement Method for a Terahertz Rotation Mirror Imaging System Based on a Scale-Recurrent Network

Chengwu You,Zhenyu Long,Defeng Liu,Kejia Wang,Jinsong Liu,Zhengang Yang,Tianyi Wang,Wei Liu

doi:10.3390/electronics10222821

Abstract

The terahertz (THz) rotation mirror imaging system is an alternative to the THz array imaging system. A THz rotation mirror imaging system costs less than a THz array imaging system, while the imaging speed of a THz rotation mirror imaging system is much higher than the imaging speed of a THz raster-scan imaging system under the same hardware conditions. However, there is some distortion in the THz image from the THz rotation mirror imaging system. The distortion, which makes images from the THz rotation mirror imaging system difficult to identify, results from the imaging principle of the THz rotation mirror imaging system. In this article, a method based on the scale-recurrent network (SRN) is put in place to correct the distortion. A comparison between distorted THz images and corrected images shows that the proposed method significantly increases the structural similarity between the THz images and the samples.

Highlights

THz waves are electromagnetic waves ranging from 0.1 THz to 10 THz [1]
A method based on the scale-recurrent network (SRN) is introduced to correct the distortion of the THz rotation mirror imaging system, considering that the basic outlines of the sample in the THz image are unchanged
When the network is in training, the initial learning rate is set to 2.7 × 10−6, the batch

Summary

Introduction

THz waves are electromagnetic waves ranging from 0.1 THz to 10 THz [1]. THz waves are nonionizing [2] and have the ability to penetrate foam [3], ceramic [4], and magnetic material [5] as well as polymer composites [6]. The THz imaging technique has great application prospects for non-contact [7,8] and non-destructive [9,10] detection. The use of terahertz radiation has a very promising future in medical imaging due to its nonionizing properties [11]. In the last 20 years, research on THz imaging has been conducted on a large scale [12,13]. There are two types of THz imaging techniques. One is called the THz active imaging technique, which includes THz computed tomography (CT) [14], THz synthetic aperture radar (SAR) [15], terahertz frequency-modulated continuous wave (FMCW) radar [16], THz timedomain spectroscopy (TDS) [17] and THz scanning near-field microscopy (SNOM) [18], etc

Methods

Results

Conclusion