CT Image Reconstruction Based on the Scale-Space Radon Transform

With the aim to improve the reconstructed image quality in Computed Tomography (CT) using filtered Backprojection (FBP), we propose to model the X-ray beam with the Scale Space Radon Transform (SSRT) instead of the Radon Transform (RT), where the assumptions made on the physical dimensions of the CT system elements, such as the X-ray focal spot, the detector cell and the image voxels, reflect better the reality. The FBP algorithm is used to reconstruct the image from the SSRT sinogram, where the RT spectrum used in FBP is replaced by SSRT and the Gaussian kernel, expressed in their frequency domain. PSNR and SSIM, as quality measures, are used to compare RT and SSRT-based image reconstruction on Shepp-Logan head and anthropomorphic abdominal phantoms. The experiments show an outstanding performance of SSRT-based image reconstruction method compared to RT-based method, especially, when the number of projections is reduced and CT data is corrupted by Poisson-Gaussian noise, making it more appropriate for applications requiring low-dose radiation, such as medical X-ray CT.