Industrial CT Rotation Center Calibration Method Based on Weighted Average

The precise positioning of the rotation center is an important condition for reconstructing high-quality CT images. In this paper we propose a center rotation calibration method based on weighted average. First we divide the projection sinogram into two sets of projection data by limit of 180°, thus we can figure out the calibration coefficient of the two sets of projection data and their corresponding detector probes. Then we use the maximum and the sub-maximal cross-correlation coefficients to obtain the actual rotation center coordinates by weighting average the coordinate values of the detector elements. The algorithm proposed in this paper is completely based on the original projection data. There is no need to determine the geometric parameters of the CT measurement, and we can acquire sub-pixel level accuracy of the rotation center without interpolating the projection data in advance. The accuracy is higher while the implementation is quite simple.