基于面阵式探测器连续太赫兹波三维层析成像

A continuous-wave terahertz 3-D computed tomography using a pyroelectric array detector

摘要:

太赫兹波层析成像技术是利用太赫兹波的穿透性对样品进行旋转投影数据采集，通过层析重建算法获得样品的二维横截面图，并实现样品的三维内部结构图的重构。本文介绍了基于面阵式探测器连续太赫兹波层析成像系统。该成像系统的优势在于利用了面阵式探测器记录二维投影数据，相比扫描层析成像系统，提高了投影采集速率。为了获得高精确度的二维投影数据，利用角谱衍射传播算法将二维投影图传播至样品后表面，实现抑制太赫兹波在物体外部衍射效应，最终利用滤波反投影算法重建出高保真的样品三维内部结构图，并进一步探索了基于面阵式探测器的连续太赫兹波层析成像技术在无损检测和安全检测上的可行性。

Abstract:

Terahertz computed tomography makes use of the penetrability of terahertz radiation and obtains three-dimensional(3-D) object projection data. In this paper, continuous-wave terahertz computed tomography using a pyroelectric array detector is presented. Compared with scanning terahertz computed tomography, a pyroelectric array detector can obtain a large quantity of projection data in a short time. To obtain a high precision two-dimensional(2-D) projection data, the two-dimensional projection data is propagated by angular spectrum algorithm; then the diffraction effects are suppressed on external sample. Two-dimensional cross-sectional images and three-dimensional images of the internal structure of the object are obtained by the filtered back projection algorithm. Further, the feasibility of terahertz computed tomography is explored in non-destructive testing and security testing.