Simulations of three-dimensional radiometric imaging of extended sources in a security screening portal

2015 ◽  
Author(s):  
Neil A. Salmon ◽  
Nick Bowring
Keyword(s):  
Three Dimensional ◽  
Security Screening ◽  
Extended Sources

scholarly journals Three-Dimensional Holographic Imaging Using Single Frequency Microwave Data

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Reza K. Amineh ◽  
Maryam Ravan ◽  
Raveena Sharma ◽  
Smit Baua
Keyword(s):  
3D Imaging ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Single Frequency ◽  
Low Frequencies ◽  
Reconstruction Process ◽  
Security Screening ◽  
Holographic Imaging ◽  
Wave Imaging ◽  
The Media

Three-dimensional (3D) microwave and millimeter wave imaging techniques based on the holographic principles have been successfully employed in several applications such as security screening, body shape measurement for the apparel industry, underground imaging, and wall imaging. The previously proposed 3D holographic imaging techniques require the acquisition of wideband data over rectangular or cylindrical apertures. Requirement for wideband data imposes limitations on the hardware (in particular at very high or very low frequencies). It may also lead to errors in the produced images if the media is dispersive (e.g., in biomedical imaging) and not modeled properly in the image reconstruction process. To address these limitations, here, we propose a technique to perform 3D imaging with single frequency data. Instead of collecting data at multiple frequencies, we acquire the backscattered fields with an array of resonant antennas. We demonstrate the possibility of 3D imaging with the proposed setup and perform a comprehensive study of the capabilities and limitations of the technique via simulations. To perform a realistic study, the simulation data is contaminated by noise.

scholarly journals Three-dimensional cross-nanowire networks recover full terahertz state

Science ◽  
2020 ◽  
Vol 368 (6490) ◽  
pp. 510-513 ◽  
Author(s):  
Kun Peng ◽  
Dimitars Jevtics ◽  
Fanlu Zhang ◽  
Sabrina Sterzl ◽  
Djamshid A. Damry ◽  
...  
Keyword(s):  
Polarization State ◽  
Three Dimensional ◽  
Wide Band ◽  
Field Vector ◽  
Infrared Light ◽  
Electromagnetic Spectrum ◽  
Polarization Component ◽  
Security Screening ◽  
Orthogonal Components ◽  
Nanowire Networks

Terahertz radiation encompasses a wide band of the electromagnetic spectrum, spanning from microwaves to infrared light, and is a particularly powerful tool for both fundamental scientific research and applications such as security screening, communications, quality control, and medical imaging. Considerable information can be conveyed by the full polarization state of terahertz light, yet to date, most time-domain terahertz detectors are sensitive to just one polarization component. Here we demonstrate a nanotechnology-based semiconductor detector using cross-nanowire networks that records the full polarization state of terahertz pulses. The monolithic device allows simultaneous measurements of the orthogonal components of the terahertz electric field vector without cross-talk. Furthermore, we demonstrate the capabilities of the detector for the study of metamaterials.

An efficient design method for LED surface sources in three-dimensional rotational geometry using projected angle difference  An efficient design method for LED surface sources

2018 ◽  
Vol 51 (3) ◽  
pp. 457-464 ◽  
Author(s):  
X Li ◽  
P Ge ◽  
H Wang
Keyword(s):  
Design Method ◽  
Near Field ◽  
Three Dimensional ◽  
Optical Systems ◽  
Two Dimensional ◽  
Efficient Design ◽  
Angle Difference ◽  
Extended Sources ◽  
The Relationship ◽  
Better Than

An efficient method is proposed for the design of prescribed rotational illumination on the far or near field using the edge-ray principle. By this method, the prescribed illuminance on the prescribed location can be determined by projected angle difference in a two-dimensional design process for LED extended sources. Profiles of the lens with two initial curves on the centre can be calculated based on the relationship between the illuminance and the projected angle difference. The initial optical systems we calculated are close to the prescribed illumination despite the influence of skew rays. More importantly, a prescribed illumination on the near field can be achieved accurately and quickly by using this method, which is better than the usual luminous intensity distribution design methods for LED extended sources.

scholarly journals Prescribed intensity design for extended sources in three-dimensional rotational geometry

2015 ◽  
Vol 40 (9) ◽  
pp. 2130 ◽  
Author(s):  
Rengmao Wu ◽  
Yi Qin ◽  
Hong Hua ◽  
Youri Meuret ◽  
Pablo Benítez ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Extended Sources

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Sign in / Sign up

Export Citation Format

Share Document