Study On Analytical Methods For X-ray CT Imaging Metal Artifacts Reducing

Nowadays,X-ray computed tomography technology has been active in various fields.Specially it is widely used in industrial nondestructive testing and medically assisted diagnosis.The characteristic of CT is that it can obtain the information inside the object without damaging the physical structure of that.In practical application,the projection data measured by the detector often contains a variety of errors,which is represented by noise and beam-hardening,etc.The specific performance is the introduction of artifacts found in the reconstructed image that reduces the image quality.Especially in the clinical application of CT images,patients are often equipped with metal implants or some metal interventional therapy equipment,which will produce metal artifacts in the CT reconstruction images caused by a variety of physical effects.The cause of metal artifacts is complex,and the metal material as well as shape size will directly lead to different strength and distribution of the artifacts.Although there are some papers and patents about the method of metal artifacts reduction,there is still no general method to eliminate or reduce the metal artifact.Therefore,it is of great significance to study a widely applicable method of metal artifact reduction for CT imaging.Aiming at the problem of metal artifacts in medical CT images,this paper studies a method of reducing metal artifacts.The difference between polychromatic energy spectrum and the projection data under single energy spectrum is firstly analyzed,then reconstructing by CT reconstruction system,obtaining metal objects from the reconstruction image by image segmentation,and then reconstructing the artifact images with metal objects projection and preprocessing,finally minus the artifact images from original image for the target image,that is the image after correction.In this paper,the artifact reduction method can effectively reducing banded artifacts,at the same time,it can maintain the structure characteristics of the original information,and does not require prior information of X-ray energy spectrum and the original projection data.