Optimization of a multi-source rectangular X-ray CT geometry for inline inspection

Abstract

A fast-moving economy requires X-ray technology that inspects container traffic promptly and with high accuracy to identify nonconforming cargo. Unfortunately, conventional X-ray CT with a rotating gantry cannot be used because of the limited throughput. Instead, X-ray radiographs are acquired, but these do not provide depth information of the objects to be inspected. A novel solution is to use rotation-free CT geometries, which aim to preserve the image quality by using multiple static X-ray sources, albeit their optimal position and orientation have not been extensively studied to date. In this work, we investigate a rectangular, fixed-gantry CT geometry, for which we implemented a comprehensive simulation framework using the ASTRA Toolbox.(1) In addition, the orientation of the X-ray sources was optimized to perform ROI imaging with enhanced image quality, in terms of the mean squared reconstruction error. Lastly, we challenged the equidistant distribution of X-ray sources as the preferred configuration and compared the reconstructions with those of a projected circular distribution. Although spatially bound improvements were observed, future research is required.