Patent application number | Description | Published |
20080310598 | Method for calibrating dual-energy CT system and method of image reconstruction - A method for calibrating a dual-energy CT system and an image reconstruction method are disclosed to calculate images of atomic number and density of a scanned object as well as its attenuation coefficient images at any energy level. The present invention removes the effect from a cupping artifact due to X-ray beam hardening. The method for calibrating a dual-energy CT system is provided comprising steps of selecting at least two different materials, detecting penetrative rays from dual-energy rays penetrating said at least two different materials under different combinations of thickness to acquire projection values, and creating a lookup table in a form of correspondence between said different combinations of thickness and said projection values. The image reconstruction method is provided comprising steps of scanning an object with dual-energy rays to acquire dual-energy projection values, calculating projection values of base material coefficients corresponding to said dual-energy projection values based on a pre-created lookup table, and reconstructing an image of base material coefficient distribution based on said projection values of base material coefficients. In this way, images of atomic number and density of an object as well as its attenuation coefficient images can be calculated from the images of the distribution of base material coefficients. Compared with the prior art technique, the method proposed in the present invention has advantages of simple calibration procedure, high calculation precision and invulnerability to X-ray beam hardening. | 12-18-2008 |
20090003516 | X-Ct Scan System - An X-CT scan system includes a base, an object rotary support, an X-ray generation device and a data acquisition system, wherein one side of the detector is leveled to or beyond the prolong line of the connecting line between the X-ray source of the X-ray generation device and the center of the object rotary support, the length of the beyond portion is less than the radius of the imaging field. The advantage of the invention is in that the invention can reconstruct the entire image of the object by means of X-ray projection data which only covers half of the area of the object. Compared with the traditional CT scan system, half of the detector size can be saved at most. The X-CT scan system is simplified and the projection data amount for scan and computation amount for image reconstruction are also reduced with the reconstructed image quality guaranteed. | 01-01-2009 |
20090129544 | METHOD AND APPARATUS FOR SUBSTANCE IDENTIFICATION - A method for substance identification and an apparatus thereof are disclosed. The method comprises comprising steps of: transmitting an object under inspection using high-energy rays and low-energy rays, so as to obtain a high-energy transmission image and a low-energy transmission image for the object, wherein a value of each pixel in the high-energy image indicates a high-energy transparency of the high-energy rays with respect to corresponding parts of the object, and a value of each pixel in the low-energy image indicates a low-energy transparency of the low-energy rays with respect to corresponding parts of the object; calculating a value of a first function for the high-energy transparency and a value of a second function for the high-energy transparency and the low-energy transparency, for each pixel; and classifying locations determined by the value of the first function and the value of the second function using a pre-created classification curve, so as to identify the type of the substance of a part of the object corresponding to each pixel. With the present invention, it is possible to not only obtain a transmission image of the object, but also obtain material information in the object. | 05-21-2009 |
20090262891 | LINEAR TRACK SCANNING IMAGING SYSTEM AND METHOD - In a linear track scanning imaging system and method, the imaging system may include: a ray generating unit having a plurality of ray sources that emit beams alternately, only one ray source at a time; an actuating arrangement causing an object under examination to move with respect to the linear track scanning imaging system along a linear track, leading the object to pass through a scanning area of the linear track scanning imaging system; a data collecting unit that collects projection data of the object for each ray source; an imaging unit that reconstructs an image of the object under examination based on the projection data collected for each ray source; and a display unit for displaying the reconstructed image. | 10-22-2009 |
20110293064 | X-RAY DARK-FIELD IMAGING SYSTEM AND METHOD - 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 G | 12-01-2011 |
20120106832 | METHOD AND APPARATUS FOR CT IMAGE RECONSTRUCTION - 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. | 05-03-2012 |
20130094625 | X RAY SOURCE GRATING STEPPING IMAGING SYSTEM AND IMAGE METHOD - 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 detector is compared with a light intensity curve in the absence of the object to be detected, a pixel value of each pixel point is calculated from change in said light intensity curve; an image of the detected object is reconstructed according to the calculated pixel value. | 04-18-2013 |
20140093152 | METHODS AND DEVICES FOR LOCATING OBJECT IN CT IMAGING - The present disclosure provides methods and devices for locating a plurality of interested objects in CT imaging. Location of the interested objects in the three-dimensional space can be determined by using three projection images that are substantially perpendicular to each other. The method can rapidly locate interested objects in a CT image without pre-reconstruction of the CT image even if there are a plurality of interested objects in the field of view. The algorithm does not involve interactive steps. The method is rapid and effective, and thus applicable to industrial applications. | 04-03-2014 |