Geometric correction of cone beam computed laminography based on projected address translation

Abstract

Precise alignment of the system scan geometry is crucial to the reconstruction quality of computed laminography (CL). Different from computed tomography (CT), a challenging task for CL image reconstruction is to deal with rotational axes that are no longer symmetrical. In this paper, we take advantage of the fact that the difference between the inverse of the projected transverse coordinates of two points rotated about the axis of rotation under the CL scan geometry sums to zero when the projection angle differs by 180 deg. Based on this fact, the projection data under the scanned geometry with errors are aligned to the theoretical projection geometry. To validate this calibration method, a numerical printed circuit board (PCB) phantom was simulated. The results demonstrate that this method is capable of achieving high accuracy compared to the previous methods. The experimental results on printed circuit boards (PCB) demonstrate that the method can effectively improve geometric alignment accuracy of CL and obtain high-resolution reconstructed images.