Accurate PSF determination in x ray image restoration.

When a source's focal spot is known, an x ray image can be significantly improved by a deconvolution algorithm with the point spread function (PSF). We propose a simple method to measure the PSF for image restoration using x ray speckle imaging. In this method, the PSF is reconstructed with intensity and total variation constraints from a single x ray speckle of an ordinary diffuser. Compared with the traditional time-consuming measurement with a pinhole camera, the speckle imaging method is fast and easy to execute. When the PSF is available, we use a deconvolution algorithm to reconstruct the sample's radiography image, and the result provides more structural details than the original images.