Automatic calibration method for reconstructing voxel sizes of cone beam 3D-CT scanning system

The invention discloses an automatic calibration method for reconstructing voxel sizes of a cone beam 3D-CT scanning system. The method comprises utilizing diameter information of DR projection of spherical target bodies under different stroke distances along an X axis, using a least squares method for regression of a stroke-voxel size relationship V=b+kD under different imaging positions, and then embedding the V=b+kD in an automatic calibration module of the cone beam 3D-CT scanning system. When the cone beam 3D-CT scanning system operates, the calibration module automatically calculates exact values of the voxel sizes according to different scanning positions, thereby ensuring accuracy of data analysis and characteristic measurement based on 3D-CT images. The calibration method prevents difficulties of large difficulty in calculating a projective geometry amplification ratio and low precision existing in present calibration method, does not need to calibrate standard components after a CT scanning, and has advantages of simple operation, high precision and high automatic degree.