In the first part of this work, we present two methods for improving the shape-threat detection performance of x-ray computed tomography. Our work uses a fixed-gantry system employing 25 x-ray sources. We first utilize Kullback-Leibler divergence and Mahalanobis distance to determine the optimal single-source single-exposure measurement. The second method employs gradient search on Bhattacharyya bound on error rate (P-e) to determine an optimal multiplexed measurement that simultaneously utilizes all available sources in a single exposure. With limited total resources of 10(6) photons, the multiplexed measurement provides a 41.8x reduction in P-e relative to the single-source measurement. In the second part, we consider multiple exposures and develop an adaptive measurement strategy for x-ray threat detection. Using the adaptive strategy, we design the next measurement based on information retrieved from previous measurements. We determine both optimal "next measurement" and stopping criterion to insure a target P-e using sequential hypothesis testing framework. With adaptive single-source measurements, we can reduce P-e by a factor of 40x relative to the measurements employing all sources in sequence. We also observe that there is a trade-off between measurement SNR and number of detectors when we study the performance of systems with reduced detector numbers. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/624371 |
| Date | 08 December 2016 |
| Creators | Masoudi, Ahmad, Thamvichai, Ratchaneekorn, Neifeld, Mark A. |
| Contributors | Univ Arizona, Elect & Comp Engn Dept, Univ Arizona, Coll Opt Sci, University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United States, University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United States, University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United StatesbUniversity of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States |
| Publisher | SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016 Society of Photo-Optical Instrumentation Engineers |
| Relation | http://opticalengineering.spiedigitallibrary.org/article.aspx?doi=10.1117/1.OE.56.4.041308 |
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