Metal artifact suppression in terahertz computed tomography.

Metal artifact suppression in images of terahertz computed tomography is a bottleneck problem that hinders the development of this technique, and few studies have been conducted so far. In this paper, we propose a metal artifact suppression method containing 8 steps based on the idea of sinogram restoration. The method has been applied to the slice images of several metal objects and the effects before and after metal artifact suppression have been compared to verify the effectiveness of the method.

Terahertz fan-beam computed tomography.

A terahertz (THz) fan-beam computed tomography (CT) system using a 0.3 THz continuous-wave sheet beam is proposed. The diffraction-free sheet beam expands in a fan shape in only one direction and provides propagation-invariant focal lines and extended the depth-of-field.

Generation of a meter-scale THz diffraction-free beam based on multiple cascaded lens-axicon doublets: detailed analysis and experimental demonstration.

An effective approach is proposed for obtaining a long-distance THz diffraction-free beam with meter-scale length. Multiple 3D-printed lens-axicon doublets are cascaded to form the generation system. In order to manifest the physical mechanism behind the generation process of this long-distance diffraction-free beam, we make a detailed comparative analysis of three beams: the ideal Bessel beam, the quasi-Bessel beam generated by single axicon, and the diffraction-free beam generated by the lens-axicon doublets.