120 results about "Differential phase contrast" patented technology

A device for imaging an object, such as for breast imaging, includes a gantry frame having mounted thereon an x-ray source, a source grating, a holder or other place for the object to be imaged, a phase grating, an analyzer grating, and an x-ray detector. The device images objects by differential-phase-contrast cone-beam computed tomography. A hybrid system includes sources and detectors for both conventional and differential-phase-contrast computed tomography.

The present invention generally refers to a correction method for grating-based X-ray differential phase contrast imaging (DPCI) as well as to an apparatus which can advantageously be applied in X-ray radiography and tomography for hard X-ray DPCI of a sample object or an anatomical region of interest to be scanned. More precisely, the proposed invention provides a suitable approach that helps to enhance the image quality of an acquired X-ray image which is affected by phase wrapping, e.g. in the resulting Moiré interference pattern of an emitted X-ray beam in the detector plane of a Talbot-Lau type interferometer after diffracting said X-ray beam at a phase-shifting beam splitter grating. This problem, which is further aggravated by noise in the obtained DPCI images, occurs if the phase between two adjacent pixels in the detected X-ray image varies by more than π radians and is effected by a line integration over the object's local phase gradient, which induces a phase offset error of π radians that leads to prominent line artifacts parallel to the direction of said line integration.

A differential phase-contrast X-ray imaging system is provided. Along the direction of X-ray propagation, the basic components are X-ray tube, filter, object platform, X-ray phase grating, and X-ray detector. The system provides: 1) X-ray beam from parallel-arranged source array with good coherence, high energy, and wider angles of divergence with 30-50 degree. 2) The novel X-ray detector adopted in present invention plays dual roles of conventional analyzer grating and conventional detector. The basic structure of the detector includes a set of parallel-arranged linear array X-ray scintillator screens, optical coupling system, an area array detector or parallel-arranged linear array X-ray photoconductive detector. In this case, relative parameters for scintillator screens or photoconductive detector correspond to phase grating and parallel-arranged line source array, which can provide the coherent X-rays with high energy.

Embodiments of methods and apparatus are disclosed for obtaining a phase-contrast digital radiographic imaging system and methods for same that can include an x-ray source for radiographic imaging; a beam shaping assembly including a collimator and a source grating, an x-ray grating interferometer including a phase grating, and an analyzer grating; and an x-ray detector, where a single arrangement of the beam shaping assembly, the x-ray grating interferometer and a position of the detector is configured to provide spectral information (e.g. at least two images obtained at different relative beam energies).

A phase retrieval method for differential phase contrast imaging includes receiving data corresponding to a differential phase image generated from a measured signal. The measured signal corresponds to an X-ray signal detected by a detector after passing through a subject located with a grating arrangement between an X-ray source and the detector. The method further includes generating a phase image corresponding to the integration of the differential phase image. Generating the phase image includes performing an iterative total variation regularized integration in the Fourier domain.

For correcting differential phase image data 52, differential phase image data 52 acquired with radiation at different energy levels is received, wherein the differential phase image data 52 comprises pixels 60, each pixel 60 having a phase gradient value 62a, 62b, 62c for each energy level. After that an energy dependent behavior of phase gradient values 62a, 62b, 62c of a pixel 60 is determined and a corrected phase gradient value 68 for the pixel 60 is determined from the phase gradient values 62a, 62b, 62c of the pixel 60 and a model for the energy dependence of the phase gradient values 62a, 62b, 62c.

The invention discloses a method and system based on a differential phase contrast imaging reduction quantitative phase image, and relates to the field of the computer imaging. The stable method from a target image to a reduction quantitative phase image is established. The method is capable of firstly establishing a differential phase contrast imaging two-dimensional optical phase transfer function H(u), and establishing the relation between the H(u), a frequency domain function of a differential phase contrast image (the figure is as shown in the specification) and the quantitative phase information, finally executing the deconvolution operation to recover the quantitative phase information through the phase transfer function of the differential phase contrast imaging. The method is capable of further researching a method of quantitatively recovering the phase information under the asymmetrical illumination pattern formed by multi-axis division so as to enhance the reconstitution capacity of the phase information in the different directions, and using the mathematical optimization to reduce the frequency noise increase caused by the direct deconvolution. The method is capable of overcoming the defects that the traditional quantitative image acquisition operation is complicated and the imaging condition is rigorous, and the obtained image resolution is higher.

The invention relates to an X-ray differential phase-contrast imaging system which has three circular gratings. The circular gratings are aligned with the optical axis of the radiation beam and a phase stepping is performed along the optical axis with the focal spot, the phase grating and/or the absorber grating. The signal measured is the phase-gradient in radial direction away from the optical axis.

The present invention discloses a dual-channel structure optical digital phase contrast microscopy imaging system and a realization method thereof, wherein the system comprises a light source, a beam expansion collimating unit, a light splitter, a lens group and two same cameras. The beam expansion collimating unit is used to adjust the divergent light emitted out by the light source into the parallel light and irradiate to a to-be-detected object, the light splitter, the lens group and the two cameras form two sets of symmetrical 4f imaging systems and obtain two synchronization images to calculate a real-time bright field micrograph, a differential phase contrast graph and a quantitative phase diagram image. Based on utilizing the common and cheap devices in the market specifically, and by processing simply, a same phase contrast imaging effect can be realized, and the problems that the devices are expensive, and a spatial light modulator is sensitive to the polarization of the light, are solved.

The present invention relates to differential phase-contrast imaging, in particular to a structure of a diffraction grating, e.g. an analyzer grating and a phase grating, for X-ray differential phase-contrast imaging. In order to make better use of the X-ray radiation passing the object, a diffraction grating (14) for X-ray differential phase-contrast imaging is provided with at least one portion (24) of a first sub-area (26) and at least one portion (28) of a second sub-area (30). The first sub-area comprises a grating structure (54) with a plurality of bars (34) and gaps (36) being arranged periodically with a first grating pitch P G (38), wherein the bars are arranged such that thy change the phase and/or amplitude of an X-ray radiation and wherein the gaps are X-ray transparent. The second sub-area is X-ray transparent and wherein the at least one portion of the second sub-area provides an X-ray transparent aperture (40) in the grating. Portions of the first and second sub-areas are arranged in an alternating manner in at least one direction (42).

The invention relates to the technical field of nanometer resolution X ray wave zone plate microscopic imaging and specifically discloses an X ray differential phase contrast microscopic imaging system and an imaging method. The system sequentially comprises an X ray light source, a collecting lens, a sample stage, an X ray wave zone plate, an absorbing ring and an imaging detector along the X ray propagation direction. The X ray differential phase contrast microscopic imaging system is provided to overcome the defects of an X ray microscope taking a wave zone plate as an objective lens, and the X ray differential phase contrast microscopic imaging system and the two-dimensional and/or three-dimensional imaging method provided by the invention can be used for quickly imaging objects.

The present invention relates to differential phase-contrast imaging of an object (108). When reconstructing image information from differential phase-contrast image data, streak- like artefacts (502) may occur. The artefacts (502) may substantially reduce legibility of reconstructed image data. Accordingly, it may be beneficial for removing or at least suppressing said artefacts (502). Thus, a method (400) for regularized phase retrieval in phase-contrast imaging is provided comprising receiving (402) differential phase-contrast image data of an object (108); generating (404) reconstructed image data of an object (108) and presenting (406) reconstructed image data of the object (108). The differential phase-contrast image and the reconstructed image data comprise a two-dimensional data structure having a first dimension and a second dimension. Generating reconstructed image data comprises integration of image data in one of the first dimension and the second dimension of the data structure. A gradient operator is determined in the other one of the first dimension and second dimension of the data structure and the data structure is employed for reconstructing image data resulting in a reduction of artefacts (500) within the reconstructed image data.

The invention discloses a transverse dislocated absorption grating-based X ray grating differential phase contrast imaging method and device. The method comprises the following steps: arranging a Talbot-Lau imaging structure by the novel transverse dislocated absorption grating disclosed by the invention; acquiring the two-dimensional intensity image after X ray penetrates through an object by the imaging structure; and separating the X ray absorption contrast image, differential phase contrast image and scattering contrast image from the acquired two-dimensional intensity image by the Fourier analysis method. Compared with the traditional method, the embodiment of the invention does not need to move the grating, three types of contrast images can be obtained by single exposure, so the imaging time is greatly shortened, the imaging dose is reduced and the imaging efficiency and stability of a system are improved.

The invention discloses an X-ray grating difference phase-contrast three-dimensional cone beam computerized tomography method and device based on transverse dislocation gratings. The method comprisesthe following steps: arranging a Talbot-Lau three-dimensional cone beam tomography structure by a transverse dislocation absorbing grating; acquiring the two-dimensional intensity image sequence of anX ray passing through an object through the structure; separating out an X-ray absorbing contrast image sequence, a differential phase-contrast image sequence and a scattering contrast image sequencefrom a collected two-dimensional intensity image by using a Fourier analysis method; and performing image reconstruction on the three contract image sequences to obtain three contract CT slicing images of the object by using an absorbing contrast filtered backprojection reconstruction algorithm, a differential phase contrast filtered backprojection reconstruction algorithm and a scattering contrast filtered backprojection reconstruction algorithm. Stepping of the absorption grating is not required, three contract CT slicing images can be obtained by a traditional CT scanning method based on X-ray attenuation, the imaging time is greatly shortened, the imaging dosage is reduced, and the system imaging efficiency and the stability are improved.