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Place ENS Paris-Saclay, Amphi d'Alembert (1Z18)
Potential and challenges of robotic X-ray tomography
Abstract
X-ray tomography (XR) is a very effective non-destructive testing (NDT) method for determining the internal structural characteristics of an object (its dimensions, shape, density) and detecting possible defects. However, current commercial systems, which generally consist of positioning the object to be inspected on a turntable in a restricted space, offer little flexibility with regard to the shape and size of the object or the intended application.
In this context, robotic inspection is one of the major challenges in the field of X-ray inspection and the Department of Imaging and Simulation for Control (DISC) of CEA LIST has acquired a robotic X-ray imaging platform. The platform is composed of two six-axis robots that respectively move a micro-focus X-ray tube and a planar detector opposite each other. As opposed to conventional X-ray tomography equipment where only circular and helical trajectories are accessible, such a platform allows great adaptability of the trajectory to integrate constraints on the object or the environment.
In addition to the possibility of inspecting large parts that cannot be positioned in conventional tomographs, such a platform makes it possible to diversify inspection strategies. For example, it can be used to take a global 2D X-ray of the part, then to zoom in on doubtful or sensitive parts and finally to take a local 3D image to characterise an area or defect in greater detail. For this last 3D reconstruction task, specific algorithms are developed to adapt to the acquisition conditions imposed by robotic inspection (limited angle of view, truncation of projections).