Three-Dimensional Terahertz Coded-Aperture Imaging in Space Domain

• Published in: IEEE access Vol. 6; pp. 32727 - 32736
• Main Authors: Chen, Shuo, Luo, Cheng-Gao, Wang, Hong-Qiang, Peng, Long, Deng, Bin, Zhuang, Zhao-Wen
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aperture imaging; Apertures; Coded-aperture imaging; correlation operation; Frequency domain analysis; frequency-domain (FD); Image resolution; Imaging; Imaging techniques; Medical imaging; Radar imaging; Signal to noise ratio; space-domain (SD); Spikes; terahertz; Terahertz frequencies; Three dimensional imaging; Three-dimensional displays; Time-domain analysis
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2018.2847898

As a promising radar imaging technique, terahertz coded-aperture imaging (TCAI) can achieve high-resolution, forward-looking, and staring imaging by producing spatiotemporal independent signals with coded apertures. However, traditional 3-DTCAI working in time domain, has two problems, that is, heavy computational burden caused by large-scale reference-signal matrix, and poor resolving ability under low signal-to-noise ratio (SNR). Frequency-domain (FD)-TCAI (FD-TCAI) is able to reduce the two problems only in a limited degree. Therefore, this paper first proposes a space-domain (SD)-TCAI (SD-TCAI) method, which achieves more effective and efficient 3-D imaging than FD-TCAI under low SNR. With correlation operation, SD-TCAI transforms the echo signals from frequency domain to space domain, where spike pulses appear in the target positions. According to different spike pulses, the 3-D imaging areas can be divided and reconstructed in parallel, and finally synthesized together to obtain the whole 3-D target. In this way, the computational burden is further reduced, leading to an improved SNR. In this paper, we build and present the imaging models and procedures of TD-TCAI, FD-TCAI, and SD-TCAI, respectively. The experimental results demonstrate that SD-TCAI has overwhelming superiority over TD-TCAI and FD-TCAI. Therefore, SD-TCAI has great potential in applications, such as security screening, nondestructive detection, and medical diagnosis.