Abstract: A spectrum measurement and estimation method for tomographic reconstruction, beam hardening correction, dual-energy CT and system diagnosis, etc., comprises determining the spectra for combinations of source acceleration voltage, pre-filters and/or detectors and after measuring the transmission values of several pre-filters, calculating corrected spectra for the combinations of the source acceleration voltage, pre-filters and/or detectors.

Abstract: A method is presented to minimize the helical pitch (P) of chiroplasmonic nanostructures to the molecular size-comparable scale. In particular, chiroplasmonic nanostructures can be used to induce plasmonic chirality via chirality transfer and used for chirality-related primary applications such as chiral sensing. In one aspect, there is provided a chiroptically active plasmonic nanoparticle with a helical pitch (P) less than its wire diameter (d) produced via a glancing angle deposition (GLAD) process.

Abstract: A segmentation-and-spectrum-based metal artifact reduction (MAR) system and method is applied in polychromatic X-ray CT system that uses a priori knowledge of high-Z metals in samples which contribute the primary artifacts at a known x-ray energy spectrum. Using a basis materials decomposition, the method solves the problem of reducing or eliminating metal artifacts associated with beam hardening using only a single scan of the sample performed at selected x-ray energy.

Abstract: X-ray microscopy tomography scanning systems are not constrained by continuous scanning trajectories like in medical scanners. In fact, the source and detector can be held stationary during subsequent image capture producing a discrete sampling pattern. For such systems, a method of producing an optimized, even illumination of the object by choosing source/detector locations on a surface of an imaginary cylinder surrounding the object is disclosed. The locations, in one example, form a regular lattice with even coverage on the surface of that cylinder, rather than at locations along a continuous curve such as a helix. Using this method, the effective pitch may be increased beyond the theoretical limit imposed by helical scanning, allowing a greater range of y-axis coverage for the same number of projection angles, corresponding to an increase in throughput.

Abstract: An X-ray imaging system comprising: an X-ray source, a source grating, a fixed grating module and an X-ray detector, which are successively positioned in the propagation direction of X-ray; an object to be detected is positioned between the source grating and the fixed gating module; said source grating can perform stepping movement in a direction perpendicular to the optical path and grating stripes; wherein the system further comprises a computer workstation for controlling said X-ray source, source grating and X-ray detector so as to perform the following processes: the source grating performs stepping movement in at least one period thereof; at each stepping step, the X-ray source emits X-ray to the object to be detected, and the detector receives the X-ray at the same time; wherein after at least one period of stepping and data acquisition, the light intensity of X-ray at each pixel point on the detector is represented as a light intensity curve; the light intensity curve at each pixel point on the detec

Abstract: A method and apparatus for CT image reconstruction may include selecting, by a unit, projection data of the same height on a curve having a curvature approximate to that of the scanning circular orbit, implementing, by a unit, a weighting processing on the selected projection data, filtering, by a unit, the weighting processed projection data along a horizontal direction, implementing, by a unit, three-dimensional back projection on the filtered projection data along the direction of ray. The method and apparatus can effectively eliminate cone beam artifact under a large cone angle.

Abstract: An x-ray imaging technology, performing an x-ray dark-field CT imaging of an examined object using an imaging system which comprises an x-ray source, two absorbing gratings G1 and G2, an x-ray detector, a controller and a data processing unit, comprising the steps of: emitting x-rays to the examined object; enabling one of the two absorbing gratings G1 and G2 to perform phase stepping motion within at least one period range thereof; where in each phase stepping step, the detector receives the x-ray and converts it into an electric signal; wherein through the phase stepping of at least one period, the x-ray intensity at each pixel point on the detector is represented as an intensity curve; calculating a second moment of scattering angle distribution for each pixel, based on a contrast of the intensity curve at each pixel point on the detector and an intensity curve without presence of the examined object; taking images of the object at various angles, then obtaining an image with scattering information of the

Abstract: An X-ray imaging system comprising: an X-ray source, a source grating, a fixed grating module and an X-ray detector, which are successively positioned in the propagation direction of X-ray; an object to be detected is positioned between the source grating and the fixed gating module; said source grating can perform stepping movement in a direction perpendicular to the optical path and grating stripes; wherein the system further comprises a computer workstation for controlling said X-ray source, source grating and X-ray detector so as to perform the following processes: the source grating performs stepping movement in at least one period thereof; at each stepping step, the X-ray source emits X-ray to the object to be detected, and the detector receives the X-ray at the same time; wherein after at least one period of stepping and data acquisition, the light intensity of X-ray at each pixel point on the detector is represented as a light intensity curve; the light intensity curve at each pixel point on the detec

Abstract: A method and apparatus for CT image reconstruction may include selecting, by a unit, projection data of the same height on a curve having a curvature approximate to that of the scanning circular orbit, implementing, by a unit, a weighting processing on the selected projection data, filtering, by a unit, the weighting processed projection data along a horizontal direction, implementing, by a unit, three-dimensional back projection on the filtered projection data along the direction of ray. The method and apparatus can effectively eliminate cone beam artifact under a large cone angle.

Abstract: An x-ray imaging technology, performing an x-ray dark-field CT imaging of an examined object using an imaging system which comprises an x-ray source, two absorbing gratings G1 and G2, an x-ray detector, a controller and a data processing unit, comprising the steps of: emitting x-rays to the examined object; enabling one of the two absorbing gratings G1 and G2 to perform phase stepping motion within at least one period range thereof; where in each phase stepping step, the detector receives the x-ray and converts it into an electric signal; wherein through the phase stepping of at least one period, the x-ray intensity at each pixel point on the detector is represented as an intensity curve; calculating a second moment of scattering angle distribution for each pixel, based on a contrast of the intensity curve at each pixel point on the detector and an intensity curve without presence of the examined object; taking images of the object at various angles, then obtaining an image with scattering information of the

Abstract: A method for phase contrast imaging comprises: illuminating an object by terahertz radiation such that the terahertz radiation interacts with the object; illuminating a diffraction grating by the terahertz radiation that has interacted with the object; translating the diffraction grating along the direction of the grating wave vector, to measure, for each of different grating positions, an intensity distribution of the terahertz radiation that has interacted with the object and with the grating in a diffraction field; and retrieving a phase contrast image of the object from the intensity distributions. An apparatus for phase contrast imaging is also provided.

Abstract: A method for phase contrast imaging comprises: illuminating an object by terahertz radiation such that the terahertz radiation interacts with the object; illuminating a diffraction grating by the terahertz radiation that has interacted with the object; translating the diffraction grating along the direction of the grating wave vector, to measure, for each of different grating positions, an intensity distribution of the terahertz radiation that has interacted with the object and with the grating in a diffraction field; and retrieving a phase contrast image of the object from the intensity distributions.