Scattering correction method of cone-beam X-ray CT based on slanted hole scattering correction plate

Compared with two-dimensional fan-beam and parallel-beam CT systems, cone-beam X-ray CT has advantages such as fast scanning speed, high X-ray utilization efficiency, consistent axial and horizontal resolution of reconstructed images, and is the focus of current industrial CT technology development. However, the imaging quality is affected by the presence of scattered radiation. In order to reduce the impact of scattered radiation on image quality, this paper proposes a new scatter correction method based on an slanted hole scatter correction plate. The principle and implementation of this method are thoroughly investigated. By acquiring raw scan data and scan data after using the slanted hole scatter correction plate, scatter field data is obtained using interpolation and smoothing techniques. Then, by subtracting the scatter field data from the original data and performing reconstruction, scatter-free CT images can be obtained. Compared with the grating-based scatter correction plate method, the results show that when applied to cone-beam CT scans of turbine blades, the contrast-to-noise ratio of typical regions (cooling channels within the blades and inner walls of the blades) is improved by 14.2% and 56.8% respectively with the slanted hole scatter correction plate method, whereas with the grating-based scatter correction plate method, the same positions only show an improvement of 5.6% and 27.6% respectively. This validates the superiority of the slanted hole scatter correction plate scatter correction method.