FBP Image Reconstruction Algorithms About Region Of Interest And Its Analysis

ABSTRACT:In order to reduce the harm of X-ray on human body, local reconstruction for the region of interest (ROI) is becoming one of the important studies in image reconstruction. The local reconstruction algorithm based on the special filter is studied. Reconstructing the local image by using the projection data through the region of interest generates the unknown constant bias in the reconstructed image in general. By making continuation along the radial direction, the unknown projections are derived from the projections in the ROI. And by reconstructing from the modified projection, the local reconstructed image is improved. The error analysis of this method based on the special filter is derived. According to the numerical experiment, the conclusion is obtained that this algorithm is available to fan beam reconstruction problem. Besides, in this paper the method of data continuation was used in attenuated local image reconstruction for the ROI, and the special filter is also used on modifying the attenuated projections. The results of the numerical experiment showed that the method of data continuation is very effective when reducing the constant bias in the cases of attenuated local image reconstruction, and by using the special filter the qualified reconstructed image with the attenuated projections can be derived as well.