Akinori Fujita

Ring artifacts reduction in cone-beam CT images based on independent component analysis

Cone-beam CT (CBCT) scanners are based on volumetric tomography, using a 2D extended digital array providing an area detector [1]. Compared to traditional CT, CBCT has many advantages, such as less X-ray beam limitation, high image accuracy, rapid scan time, etc. However, in CBCT images there are always some ring artifacts that appear as rings centered on the rotation axis. Due to the data of the constructed images are corrupted by these ring artifacts, qualitative and quantitative analysis of CBCT images will be compromised. Post processing and application such as image segmentation and registration also turn more complex as the presence of such artifacts. In this paper, a method based on independent component analysis (ICA) is presented. It deals with the reconstructed CBCT image and can effectively reduce such ring artifacts.

Independent Component Analysis for Removing X-ray Scatter in X-ray Images

Cone beam CT has a capability for the 3-dimensional imaging of large volumes with isotropic resolution. But the main limitation of cone beam CT is a larger amount of X-ray scatter. The X-ray scatter may enhance the noise in the reconstructed images. In this paper, we propose a new method based on independent component analysis (ICA) for removing the X-ray scatter in the observed X-ray images. The observed X-ray images can be considered as a linear mixture of scattered X-ray and primary X-ray. We show that the scattered X-ray and the primary X-ray can be blindly separated from two observed X-ray images by the use of ICA. The results indicate that the proposed method is effective for removing X-ray scatter from the X-ray images.