Fast-correction of Rotating Center Offset with Part Views Sinogram in 2D CT

The existing CT reconstruction algorithms depend on the precise position of the center of rotation. Without the accurate positioning, artifacts will be introduced into the reconstructed image. Sinograms with 180° or 360° views are used to estimate the rotation center. These projection require a long scan time and more computing resources. In this paper, we propose two methods for correcting the rotation center offset of parallel-beam scan and fan-beam scan, both of which only use part views of the projection data. In parallel beam scan, we use the theorem relating to the mass center of the object space and the projection space, to accurately measure the location of the rotation center in the sinogram from the 60° view. In fan beam scan, we realign the fan projection to the parallel projection, rotation center can still be measured accurately in the sonogram from the fan angle plus 60° view.