Automatic Calibration Method of Voxel Size for Cone-beam 3D-CT Scanning System

TL;DR

This paper presents an automatic, easy-to-implement calibration method for voxel size in cone-beam 3D-CT systems, ensuring accurate data analysis during rotary table movements.

Contribution

A novel calibration approach using spherical phantom projections and linear interpolation to dynamically adjust voxel size during scanning.

Findings

Method achieves high accuracy in voxel size calibration.

The calibration process is simple and suitable for real-time application.

Experimental results confirm the method's effectiveness and practicality.

Abstract

For cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary table along X-ray direction. In order to realize the automatic calibration of the voxel size, a new easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least square fitting. Through these interpolation values, a linear equation is obtained, which reflects the relationship between the rotary table displacement distance from its nominal zero position and the voxel size. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system, and when the rotary table is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy