Reconstruction Algorithms for High-Energy Computed Tomography Images of Rocket Motors

ABSTRACT: High Energy X-ray computed tomography (CT) is used to inspect the integrity of solid rocket motors. The purpose of this proposal is to improve the detection of defects when they are obscured due to physical limitations of CT. Lickenbrock has developed an advanced variant of the expectation-maximization (EM) algorithm, and other algorithms, for improving fidelity of CT. The EM algorithm is an iterative CT algorithm. It has a limitation of long computation times with large image volumes involving 100's of CT slices. Approaches to accelerating its computation speed involves the utilization of many parallel graphical processing units on one computer. Algorithmic speed improvement approaches include a mathematical formulation that improves progress of the algorithm at each iteration. Additionally, algorithms that reduce noise and artifacts that can obscure defects and are due to practical physical limitations of the CT scanner are being developed. Phase I showed the feasibility of significantly increasing speed and significantly improving image fidelity. Phase II will involve implementing and improving a complete working system and deploying the system at the Hill AFB CT Facility. The Phase III commercialization will involve a software and computer workstation product that will be a 3rd party add-on to industrial CT systems. BENEFIT: The benefit to the Department of Defense will be the capability to deploy improved computed tomography (CT) algorithms for improving defect detection in solid rocket motor inspection. Commercial applications include automotive components, baggage handling at airports, and micro CT for small animal, tissue-engineering and materials imaging.