Processing of projections containing phase contrast in laboratory micro-computerized tomography imaging
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Applied Crystallography |
| MU Faculty or unit | |
| Citation | |
| Web | http://journals.iucr.org/j/issues/2013/04/00/xk5002/xk5002.pdf |
| Doi | http://dx.doi.org/10.1107/S002188981300558X |
| Field | Solid matter physics and magnetism |
| Keywords | phase-contrast imaging; X-ray imaging; X-ray radiography; digital radiography; computerized tomography; computed radiography |
| Description | Free-space-propagation-based imaging belongs to several techniques for achieving phase contrast in the hard X-ray range. The basic precondition is to use an X-ray beam with a high degree of coherence. Although the best sources of coherent X-rays are synchrotrons, spatially coherent X-rays emitted from a sufficiently small spot of laboratory microfocus or sub-microfocus sources allow the transfer of some of the modern imaging techniques from synchrotrons to laboratories. Spatially coherent X-rays traverse a sample leading to a phase shift. Beam deflection induced by the local change of refractive index may be expressed as a dark-bright contrast on the edges of the object in an X-ray projection. This phenomenon of edge enhancement leads to an increase in spatial resolution of X-ray projections but may also lead to unpleasant artefacts in computerized tomography unless phase and absorption contributions are separated. The possibilities of processing X-ray images of lightweight objects containing phase contrast using phase-retrieval methods in laboratory conditions are tested and the results obtained are presented. For this purpose, simulated and recorded X-ray projections taken from a laboratory imaging system with a microfocus X-ray source and a high-resolution CCD camera were processed and a qualitative comparison of results was made. |
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