Figure 2
Differences in reconstruction due to differences in backprojector and filter implementations. (a) A 33 × 33 phantom with one bright pixel. (b) Sinogram of the phantom (computed using a strip kernel from the ASTRA toolbox). (c) Differences in (unfiltered) backprojection when using different backprojectors: (left to right) backprojection using a CPU line kernel from the ASTRA toolbox, backprojection using a GPU pixel-driven kernel from the ASTRA toolbox, absolute difference between the two backprojections. (d) Differences in reconstruction when using different filtering routines in FBP with the gpu-pixel kernel as backprojector: (left to right) reconstruction using filtering in real space with the Ram–Lak filter, reconstruction using the ramp filter in Fourier space, absolute difference between the two reconstructions. |