Figure 3
Flat-field-corrected projections of a projection acquired at 0° subtracted with a projection acquired at 180° (after horizontal flipping). (A) Original misplacement of sample and (B) after correction of the sample movement via rapid alignment and forward projecting (number of iterations: 40), which severely reduces the sample-movement error seen in (A), especially at the top of the sample (displayed as upside-down in XRM mode). The images are displayed on a 32-bit grey-level scale. Similar features have been marked with arrow heads. (Note that the correction of the projections worked better on the top of the sample than on the bottom part, which is most likely related to a slight wobble or tilt of the rotation axis, which could not be `entirely' corrected for by the rapid alignment algorithm.) |