(a)
(b)
(c)
(d)
Figure 4: Reformatted coronal slices of the phantom. (a) Images reconstructed from noise-free projection images using ordered subset expectation maximisation reconstruction. (b) Autoregressive filtering before and after ordered subset expectation maximisation reconstruction. (c) Filtered back projection reconstruction method preceded by Butterworth. (d) Ordered subset expectation maximisation reconstruction followed by Butterworth filtering. Stacks with the highest activity. Intermediate count level. The images are individually scaled to their own maximum.