Purpose: To investigate how an intrinsic speckle-tracking approach to speckle-based X-ray imaging can be used to extract an object's effective dark-field signal, which is capable of providing object information in three dimensions. Approach:The effective dark-field signal was extracted using a Fokker-Planck type formalism, which models the deformations of illuminating reference-beam speckles due to both coherent and diffusive scatter from the sample. We here assumed that (a) small-angle scattering fans at the exit surface of the sample are rotationally symmetric, and (b) the object has both attenuating and refractive properties. The associated inverse problem, of extracting the effective dark-field signal, was numerically stabilised using a "weighted determinants" approach.Results: Effective dark-field projection images are presented, as well as the dark-field tomographic reconstructions of the wood sample. Dark-field tomography was performed using a filtered-back projection reconstruction algorithm. The dark-field tomographic reconstructions of the wood sample provided complementary, and otherwise inaccessible, information to augment the phase-contrast reconstructions, which were also computed.Conclusions: An intrinsic speckle-tracking approach to speckle-based imaging can tomographically reconstruct an object's dark-field signal at a low sample exposure and with a simple experimental set-up. The obtained dark-field reconstructions have image quality comparable to alternative X-ray dark-field techniques.

No abstract

No abstract

Abstract.A dedicated micro-tomography beamline is proposed for the Australian Synchrotron. It will enable highresolution micro-tomography with resolution below a micron and supporting phase-contrast imaging modes. A key feature of the beamline will be high-throughput/high-speed operation enabling near real-time micro-tomography.

has made contributions to the development and application of novel theoretical and computational approaches to 2D, 3D and 4D image reconstruction and structure characterisation in application to X-ray imaging and diffraction. These approaches were successfully used in experiments at numerous laboratory and synchrotron radiation sources (Photon Factory, Japan; SPring-8, Japan; ELETTRA, Italy; ESRF, France; Australian Synchrotron). In particular, Dr Pavlov has developed new theoretical approaches in diffraction tomography, deterministic coherent diffractive imaging, phase-contrast imaging/tomography and extended the statistical dynamical X-ray diffraction theory to multilayer structures and nanostructures.