FDK reconstructions of Shepp-Logan phantom.

<p>From left to right are cross-section, sagittal view and coronal view, respectively. Row (A): phantom images; Row (B): the reconstruction with ray-driven projection and ray-driven back-projector (RMSE = 7.11%); Row (C) reconstruction with distance-driven projection and distance-driven back-projector (RMSE = 5.06%); Row (D): the reconstruction with linear interpolation based FSNP (256 sampling points per ray) and voxel-driven back-projector (RMSE = 5.30%); Row (E): the reconstruction with linear interpolation based FSNP (512 sampling points per ray) and voxel-driven back-projector (RMSE = 5.22%); Row (F): the reconstruction with blob based FSNP (256 sampling points per ray) and voxel-driven back-projector (RMSE = 2.98%).