The Filtered Back Projection Algorithm Involving A New Scanning Mode

Fan-beam CT (computed tomography), which is easy to be implemented and be controlled in practice, is widely used in clinical medicine .While the fast 3-D spiral reconstructing images method will be the mainstream in feature research, It is still valuable to research the fan-beam CT. So the reconstructing algorithm involving the fan-beam scanning is the research subject in this article.We propose the fan-beam CT involving collinear equispaced detector. In the global and local reconstruction, we propose the 2-D fan-beam filtered back projection algorithm (FBP)[3] with a new window function[1,2]. In simulation experience, by comparing the global and local reconstruction images by new window function and general window function, the new window function is estimated.Sometimes the rotation radius of the region of interest is too large to be inside the scanning range in industrial CT. On the base of the Huitao Zhang,Peng Zhang's work, the image reconstruction formula involving the new scan mode is given in this paper. A new local reconstruction algorithm is constructing using the recomposition method in the new reconstructing mode. During the simulation experience, the reconstructing using the local projection data is implemented. By comparing the data of original image and reconstruction image, it is easy to find that the filtered back projection algorithm is effective and easy to be implemented in the new scanning mode.