Active imaging at 350 GHz for security applications

David M. Sheen; Douglas L. McMakin; Jeffrey Barber; Thomas E. Hall; Ronald H. Severtsen

doi:10.1117/12.778011

22 April 2008 Active imaging at 350 GHz for security applications

David M. Sheen, Douglas L. McMakin, Jeffrey Barber, Thomas E. Hall, Ronald H. Severtsen

Proceedings Volume 6948, Passive Millimeter-Wave Imaging Technology XI; 69480M (2008) https://doi.org/10.1117/12.778011
Event: SPIE Defense and Security Symposium, 2008, Orlando, Florida, United States

Abstract

Imaging in the sub-millimeter wave range of 300 - 1000 GHz is useful for a variety of applications including security screening, imaging through obscurations, and non-destructive evaluation. Waves in this frequency range have wavelengths ranging from 0.3 to 1.0 mm and are able to penetrate many optical obscurants. The ability to form high-resolution images that penetrate clothing makes imaging in this frequency range particularly interesting for personnel security screening at standoff distances. The Pacific Northwest National Laboratory (PNNL) has previously developed portal screening systems that operate at the lower end of the millimeter-wave frequency range around 30 GHz. These systems are well suited for screening within portals and can achieve resolution of about 5 mm at ranges of less than 1 meter. However, increasing the range of these systems would dramatically reduce the resolution due to diffraction at their relatively long wavelength. Operation at much higher frequencies, for example 350 GHz, will enable an order of magnitude improvement of the resolution at a given range, while still achieving adequate clothing penetration. PNNL's portal imaging systems have relied on wavefront reconstruction, or holographic, imaging techniques to mathematically focus the imagery. In the sub-millimeter-wave, this may not always be practical due to sensitivity of the system to slight changes in the position of the imaging target during data collection. In this case, physical focusing using lenses or reflectors may be more practical. In this paper, we examine the effectiveness of imaging near 350 GHz for security screening applications. Imaging results are presented using the holographic wavefront reconstruction technique, as well as a focused reflector-based imaging system.

Citation Download Citation

David M. Sheen, Douglas L. McMakin, Jeffrey Barber, Thomas E. Hall, and Ronald H. Severtsen "Active imaging at 350 GHz for security applications", Proc. SPIE 6948, Passive Millimeter-Wave Imaging Technology XI, 69480M (22 April 2008); https://doi.org/10.1117/12.778011

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available