Motion correction for passive radiation imaging of small vessels in ship-to-ship inspections

Abstract

Passive radiation detection remains one of the most acceptable means of ascertaining the presence of illicit nuclear materials. In maritime applications it is most effective against small to moderately sized vessels, where attenuation in the target vessel is of less concern. Unfortunately, imaging methods that can remove source confusion, localize a source, and avoid other systematic detection issues cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing system sensitivity. This is particularly true for the smaller watercraft, where passive inspections are most valuable. We have developed a combined gamma-ray, stereo visible-light imaging system that addresses this problem. Data from the stereo imager are used to track the relative location and orientation of the target vessel in the field of view of a coded-aperture gamma-ray imager. Using this information, short-exposure gamma-ray images are projected onto the target vessel using simple tomographic backprojection techniques, revealing the location of any sources within the target. The complex autonomous tracking and image reconstruction system runs in real time on a 48-core workstation that deploys with the system.

Ground Penetrating Radar as a Contextual Sensor for Multi-Sensor Radiological Characterisation

“…The use of video camera image data to correct blurring of moving source images was also applied in [ 36 ] for ship to ship inspection in order to detect maritime smuggling of nuclear materials. The blurring of the image in this case is a result of wave action, which keeps both the inspection and target vessels in continuous motion.…”

“… ( a ) Reconstructed image of moving source without (top) and with (bottom) motion compensation [ 27 ]; ( b ) 3D tomographic radiation source image on a stationary volume collapsed to the x - y , y - z , x - z planes [ 36 ]. …”

A novel method for assessing imaging quality of coded-aperture gamma-ray camera to radioactive plane source

“…Gamma-ray imaging technology has been widely exploited in many radiation-monitoring-related fields, including that of environmental radiation and nuclear facility operations as well as nuclear material decommissioning and nuclear security [1][2][3][4][5][6][7]. Coded-aperture imaging technology has been applied in radiation monitoring fields specifically because of its wide energy range and high angular resolution [8][9][10].…”