Correlated Statistical Uncertainties in Coded-Aperture Imaging

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

OSTI ID:1148866

Fleenor, Matthew C ^[1]; Blackston, Matthew A ^[1]; Ziock, Klaus-Peter ^[1]

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1. ORNL

In nuclear security applications, coded-aperture imagers provide the opportu- nity for a wealth of information regarding the attributes of both the radioac- tive and non-radioactive components of the objects being imaged. However, for optimum benefit to the community, spatial attributes need to be deter- mined in a quantitative and statistically meaningful manner. To address the deficiency of quantifiable errors in coded-aperture imaging, we present uncer- tainty matrices containing covariance terms between image pixels for MURA mask patterns. We calculated these correlated uncertainties as functions of variation in mask rank, mask pattern over-sampling, and whether or not anti- mask data are included. Utilizing simulated point source data, we found that correlations (and inverse correlations) arose when two or more image pixels were summed. Furthermore, we found that the presence of correlations (and their inverses) was heightened by the process of over-sampling, while correla- tions were suppressed by the inclusion of anti-mask data and with increased mask rank. As an application of this result, we explore how statistics-based alarming in nuclear security is impacted.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1148866
• Journal Information: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. SORMA
• Country of Publication: United States
• Language: English