Publications by authors named "Toru Den"
We have developed a sparse phase-stepping (SPS) method for x-ray Talbot-Lau interferometry, which first constructs a SPS intensity pattern of fewer images than the conventional phase-stepping (PS) method and then fills the data gap with neighboring pixels for phase retrieval. The SPS method is highly beneficial in practice since the fundamental difference in spatial resolution between the SPS and PS methods becomes negligible due to the blur caused by an interferometer. The concept of the SPS method has been proved by the experiment using a small effective source size.
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- A Talbot-Lau interferometer with 2D gratings and an X-ray tube was used to explore a phase-contrast imaging method that detects phase gradients in two directions.
- Fourier analysis of Moiré fringe patterns helped create differential phase and scattering images from a single exposure, revealing clear 2D structures of plastic phantoms and soft tissue features at 17.5 keV.
- The study also examined the spatial resolution of various phase retrieval methods, finding that the choice of method had little impact on image blur, while a large effective source size increased image intensity.
We demonstrate a single shot two-dimensional grating-based X-ray phase-contrast imaging using a synchrotron radiation source. A checkerboard designed phase grating for π phase modulation at 17 keV and 35 keV, and a lattice-shaped amplitude grating with a high aspect ratio to shield X-rays up to 35 keV were fabricated. A Fourier analysis of Moiré fringe generated by the gratings was introduced to obtain the two-dimensional differential phase-contrast image with a single exposure.
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