Spatial Resolution Enhancement Based on Detector Displacement for Computed Tomography

In this paper, the impact of resolution enhancements of X-ray 2D projections on the spatial resolution of the reconstructed 3D computed tomography volume data is investigated. The resolution enhancement of an X-ray 2D projection is achieved by subpixel displacement of the X-ray detector which is mounted on linear stages for x- and y-positioning. Multiple projections at the same rotation angle but with different detector positions are applied to reconstruct a high resolution (HR) projection. Due to the HR projections which contain additional information, the spatial resolution of the 3D volume data is enhanced. For assessing the improvement quantitatively, the modulation transfer function (MTF) has been evaluated based on the ASTM-E 1695-95 standard. In order to reduce the reconstruction time of the 2D HR image out of the captured projections with detector displacement, the reconstruction task has been decomposed into sub-problems and implemented on a multi-GPU computer system. It is shown that multi-GPU implementations have accelerated the HR reconstruction process sufficiently such that no extra delay for the 3D CT reconstruction is generated.