METHOD AND DEVICE FOR GEOMETRIC CALIBRATION OF CT SCANNER

摘要

PROBLEM TO BE SOLVED: To eliminate artifacts and improve Modulation Transfer Function (MTF).SOLUTION: A method for geometric calibration of a CT scanner includes: establishing a complete geometric description of the CT scanner including an unknown geometric parameter for each row of detector cells; establishing a description of a forward projection function using the complete geometric description; acquiring actual projection coordinates of a calibration phantom placed in a scanning field of view (SFOV) on a current row of detector cells and corresponding to a plurality of angles; acquiring calculated projection coordinates of the calibration phantom on the current row of detector cells and corresponding to the plurality of angles using the description of the forward projection function; and acquiring a calibrated value for the at least one unknown geometric parameter by evaluating the unknown geometric parameter based on the acquired actual projection coordinates and calculated projection coordinates via a nonlinear least square fitting algorithm.