A calibration method for conformal x-ray transmission imaging system

The X-ray source using ZnO nanowires as the cold cathode is first densely integrate a large number of X-ray sources into flat panel devices. Compared with traditional ray sources, X-ray sources device based on ZnO nanowires have small size, instantaneous response, and can be electronically controlled. We propose a new conformal transmission imaging system that uses this flat-panel ray source to irradiate objects with multiple points to complete extremely low-dose projection. In order to get the final image, it is necessary to process the original projection with an image restoration method to remove the projection aliasing caused by multiple point sources. Due to the addition of iteration in the image restoration process, the error caused by the geometric parameters will gradually become larger as the iteration progresses, resulting in distortion of the final image. Therefore, geometric correction of the imaging system is required. The new imaging system has a unique geometric relationship. Based on this geometric relationship, this paper proposes a geometric correction method applied to the new imaging scheme. In this method, the angle parameters in the new imaging system are estimated using a single point volume model. It only needs one projection of the phantom, and it can derive the analytical formula about the three angle errors, which can avoid falling into a local minimum. In this paper, we give the simulation results of the calibration method, which proves the validity and accuracy of the method.