Contrast mechanism illuminated by polychromatic X-rays and tomographic correction.

Contrast mechanism of the synchrotron-based monochromatic X-ray imaging has been well-established for the analysis and interpretation of tomographic reconstruction. However, it is not suitable for the laboratory-based polychromatic X-ray imaging and tomography due to the change of illuminated X-ray coherence. Here we have proposed a new contrast mechanism of broad-spectrum-related X-ray imaging by presenting a general mixed contrast formula and its tomographic correction, determined by the coherence degree of light sources. The simulation and experimental results quantitatively verified the polychromatic contrast mechanism and tomographic correction of artifacts related to the feature distribution of spectral broadening, coherent, and incoherent scattering of an object. The new contrast mechanism provided the theoretical explanation and optimization of hard polychromatic X-ray tomography.