High-resolution terahertz coded-aperture imaging for near-field three-dimensional target

2019 ◽  
Vol 58 (12) ◽  
pp. 3293 ◽  
Author(s):  
Cheng-Gao Luo ◽  
Bin Deng ◽  
Hong-Qiang Wang ◽  
Yu-Liang Qin
Keyword(s):  
High Resolution ◽  
Near Field ◽  
Three Dimensional ◽  
Coded Aperture ◽  
Coded Aperture Imaging

scholarly journals Phaseless Terahertz Coded-Aperture Imaging Based on Incoherent Detection

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 226 ◽  
Author(s):  
Long Peng ◽  
Chenggao Luo ◽  
Bin Deng ◽  
Hongqiang Wang ◽  
Yuliang Qin ◽  
...  
Keyword(s):  
High Resolution ◽  
High Speed ◽  
Phase Retrieval ◽  
Time Frame ◽  
Frame Rate ◽  
Future Research ◽  
Coded Aperture ◽  
Main Work ◽  
Coded Aperture Imaging ◽  
The Matrix

In this paper, we propose a phaseless terahertz coded-aperture imaging (PTCAI) method by using a single incoherent detector or an incoherent detection array. We at first analyze and model the system architecture, derive the matrix imaging equation, and then study the phase retrieval techniques to reconstruct the original target with high resolution. Numerical experiments are performed and the results show that the proposed method can significantly reduce the system complexity in the receiving process while maintaining high resolution imaging capability. Furthermore, the approach of using incoherent detection array instead of single detector is capable of decreasing the encoding and sampling times, and therefore helps to improve the imaging frame rate. In our future research, the method proposed in this paper will be experimentally tested and validated, and high-speed PTCAI at nearly real-time frame rates will be the main work.

Near-field artifact reduction in planar coded aperture imaging

2001 ◽  
Vol 40 (26) ◽  
pp. 4697 ◽  
Author(s):  
Roberto Accorsi ◽  
Richard C. Lanza
Keyword(s):  
Near Field ◽  
Coded Aperture ◽  
Artifact Reduction ◽  
Coded Aperture Imaging

Radar coded aperture imaging for three dimensional target

2017 ◽  
Author(s):  
Shuo Chen ◽  
Chenggao Luo ◽  
Bin Deng ◽  
Yuliang Qin ◽  
Hongqiang Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Coded Aperture ◽  
Coded Aperture Imaging

Study of Microscale Three-Dimensional Printing Using Near-Field Melt Electrospinning

2017 ◽  
Author(s):  
Xiangyu You ◽  
Chengcong Ye ◽  
Ping Guo
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Low Cost ◽  
Near Field ◽  
Three Dimensional ◽  
Thin Wall ◽  
Direct Writing ◽  
Melt Electrospinning ◽  
Wall Structures ◽  
Jet Trajectory

Three-dimensional (3D) printing of microscale structures with high resolution (sub-micron) and low cost is still a challenging work for the existing 3D printing techniques. Here we report a direct writing process via near-field melt electrospinning to achieve microscale printing of single filament wall structures. The process allows continuous direct writing due to the linear and stable jet trajectory in the electric near-field. The layer-by-later stacking of fibers, or self-assembly effect, is attributed to the attraction force from the molten deposited fibers and accumulated negative charges. We demonstrated successful printing of various 3D thin wall structures (freestanding single walls, double walls, annular walls, star-shaped structures, and curved wall structures) with a minimal wall thickness less than 5 μm. By optimizing the process parameters of near-field melt electrospinning (electric field strength, collector moving speed, and needle-to-collector distance), ultrafine poly (ε-caprolactone) (PCL) fibers have been stably generated and precisely stacked and fused into 3D thin-wall structures with an aspect ratio of more than 60. It is envisioned that the near-field melt electrospinning can be transformed into a viable high-resolution and low-cost microscale 3D printing technology.

High-Resolution Seismic Hazard Analysis in a Complex Geological Configuration: The Case of the Sulmona Basin in Central Italy

2014 ◽  
Vol 30 (4) ◽  
pp. 1801-1824 ◽  
Author(s):  
Manuela Villani ◽  
Ezio Faccioli ◽  
Mario Ordaz ◽  
Marco Stupazzini
Keyword(s):  
High Resolution ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Near Field ◽  
Central Italy ◽  
Three Dimensional ◽  
Spectral Element ◽  
Seismic Wave Propagation ◽  
Novel Approach

This work proposes a novel approach for probabilistic seismic hazard analyses (PSHA) in the near field of active earthquake faults, in which deterministically computed ground motion scenarios, replacing empirically predicted ground motion values, are introduced. In fact, the databases of most ground motion prediction equations (GMPEs) tend to be insufficiently constrained at short distances and data may only partially account for the rupture process, seismic wave propagation and three-dimensional (3-D) complex configurations. Hence, herein, 3-D numerical simulations of a Mw = 6.4 earthquake rupture of the Sulmona fault in Central Italy, are carried out through the spectral element code GeoELSE ( f < 2.5 Hz), and the results are introduced in a PSHA, exploiting the capabilities of CRISIS2008 code. The SH results obtained highlight the combined effects of site, basin, and topographic features, and provide a “high-resolution” representation of the hazard in the Sulmona Basin, particularly at long periods. Such representation is expected to be more realistic than those based simply on a GMPE.

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