Removal of Gridline Artifacts in Cone-beam CT Based on Wavelet Transform

In cone-beam computed tomography with flat-panel imagers, scattered X-ray photons lead to reduced image quality. Insertion of an anti-scatter grid between the patient or object and the flat-panel imagers is one of the most used techniques for reducing scattered radiation. However, while the scatter is reduced, gridline artifacts can be visible. Suppressing gridline artifacts in cone-beam computed tomography is significant. In this paper, the existing methods of removing gridline artifacts are summarized. Moreover, the wavelet transform method based on spectrum coalescence is innovatively proposed for removing gridline artifacts. Wavelet transform can remove gridline artifacts effectively and without introducing wavelet transform harmonics thus reducing the loss of object details. The effectiveness of this method is verified by experiments.