Figure 6
Variation of filters with projection data. (Top) Two slices of a simulated foam phantom with differences in features. (Bottom left) Implementation-adapted filters for all slices of the foam phantom (slice-specific filters). Central slice (slice No. 128) filters for each implementation are indicated with bold lines. (Bottom right) Scatter plot of pixelwise standard deviations σ using slice-specific filters, the central slice filter and the Shepp–Logan filter. Standard deviations using the central slice filter are almost the same as those using slice-specific filters (orange dots). These points lie on a straight line (shown in black) with slope ∼1 and intercept ∼0. In contrast, standard deviations using the Shepp–Logan filter are higher than those using slice-specific filters (blue dots) for most pixels. |