Iterative Geometric Calibration Algorithm Based on Projection Point Correction

In the healthcare engineering field, the mobile X-ray system is becoming more and more popular in tomographic reconstruction and surgical navigation. The calibration of the geometric relationship between the X-ray source and detector is very important for tomographic reconstruction and surgical navigation. In this paper, an iterative geometric calibration algorithm based on projection point correction is proposed, and a double-layer calibration object is designed for calibration. Firstly, the geometric parameters are roughly estimated by using the geometric center point of the projection contour of the steel ball as the projection point. Then, through iteration, the projection points are corrected by using the relationship between the projection contour and internal parameters of the steel ball. The accuracy of our algorithm is proved by simulation and practical experiments.