journal menu
![[Figure 2]](vl5049fig2mag.jpg)
|
|
Figure 2
Images of the carbon-sphere sample, collected for the various dark-field approaches compared in this study. (Top) Dual-energy propagation-based approach. Dark-field contrast is generated by the difference in local blurring between two images collected at two sufficiently different X-ray energies (Ahlers et al., 2024  ). Note that the horizontal features observed within the microsphere-filled tube at 20 keV originate from the flat-field correction. The illumination was not uniform, and the horizontal structures in it were blurred by the dark-field effects generated by the microspheres, preventing these variations from being fully divided out during the flat-field correction. This is analogous to the challenges of performing flat-field correction in the presence of strong phase effects (Homann et al., 2015), but arises here due to dark-field effects. (Middle) The sample-induced dark-field effect in the single-grid approach blurs the 2D periodic reference-grid pattern (How & Morgan, 2022). (Bottom) In speckle-based imaging, dark-field contrast can be retrieved by tracking the speckle-blur between the reference-speckle and sample-plus-speckle images (Alloo et al., 2023; Beltran et al., 2023). The two black rectangles in the top left-hand images of this figure indicate the scale bars for the magnified and whole images (0.2 mm and 1 mm, respectively). Note that in the case of the multi-speckle approach, images are collected for multiple positions of the speckle generator, but these are not shown here. |
![[Figure 2]](vl5049fig2.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
access
