Determining fiber orientations in a fiber reinforced material with X-ray CT is challenging because the width of the individual fibers is often much smaller than the spatial resolution of the X-ray images. However, the anisotropic X-ray scattering signal of the fibers yields information about the fiber direction without the need to individually resolve them. In this work, edge illumination phase contrast imaging is used to sample the anisotropic X-ray scattering in the object along different directions. The measured scatter is represented on a sphere by a set of spherical harmonics. Next, the orientation of the fibers is extracted from the scatter function by constrained spherical deconvolution. This approach is experimentally validated, for both parallel and crossing fiber distributions in a single voxel, using Monte Carlo simulations in GATE. The retrieved fiber orientations for parallel and crossing carbon fibers are presented as result.
Edge illumination X-ray phase contrast imaging is a method which relies on two gratings to obtain attenuation, phase and dark field contrast. Current gratings consist of periodic apertures in a high-absorbing flat plate. While edge illumination was originally designed for parallel-beam imaging, it also works with cone-beam sources when the opening angle is sufficiently low. With higher opening angles, however, current gratings cause a shadow which results in a decreased intensity. In this paper, three alternative grating geometries are studied with Monte-Carlo simulations and their performance is evaluated in terms of shadowing. Results show that the alternative grating geometries significantly reduce shadowing in cone-beam based edge illumination.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.