Enhancement of spatial resolution of roentgenographic methods using deconvolution

The spatial resolution of X-ray micro radiography (alike any other imaging method) is the crucial parameter, which determines the span of possible applications. Its improvement remains a major experimental and data processing challenge. From theoretical principles the lower limit of the spatial resolution of a radiographic method is given by the size of the so-called point spread function (PSF) of the imaging system. Hence, details in the radiograms smaller than the size of the PSF cannot be theoretically distinguished. In the case of high geometrical magnification, the X-ray spot size becomes the most important factor for PSF determination. We have successfully measured in 2-D the X-ray spot shape and using deconvolution the spatial resolution has been improved for high-contrast object up to three-fold. We have successfully illustrated the approach for real biological and material structure investigations. Another possibility for resolution enhancement is sub-pixel micro-shifting of the X-ray detector used. Although this approach is quite common for optical imaging, it has not been fully investigated for X-ray imaging. In our measurements we have used sub-pixel micro-shifts of the Medipix2 detector. The method is successfully presented on real objects.