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. Author manuscript; available in PMC: 2013 Jul 27.
Published in final edited form as: Phys Med Biol. 2013 Jun 5;58(12):R63–R96. doi: 10.1088/0031-9155/58/12/R63

Figure 1.

Figure 1

(A) FBP reconstruction from simulated projections of a digital abdomen phantom. Simulations were performed on a very fine (4096×4096) grid with 0.125 mm voxels and 16 rays traced per 2 mm detector bin. All reconstructions are presented on a 512×512 grid of 1 mm voxels (“natural” voxel size for this geometry with magnification of 2). Iterative unregularised Ordered Subset Convex (OSC) reconstruction on the 512×512 grid is shown in (B) at a noise level matching the FBP image (accomplished by low-pass filtering). Despite better resolution (FWHM of the line pattern), the OSC image is plagued by edge and aliasing artifacts caused by object discretisation. Artifacts are indicated by arrows; in each case, an image of a section of the phantom is also shown using a compressed gray scale to better visualise the artifacts. OSC reconstruction on a fine grid (1024×1024) followed by downsampling to the same grid as used for FBP is illustrated in (C). Gray scale range is 0.9–1.1 g/cm3 for full images and 1.0–1.02 g/cm3 for image details. Figure adopted from (Zbijewski and Beekman 2004a).