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公开(公告)号：US20180174335A1
公开(公告)日：2018-06-21
申请号：US15580488
申请日：2016-06-06
Applicant: Hitachi, Ltd.
Inventor： Keisuke YAMAKAWA , Shinichi KOJIMA
CPC classification number: G06T11/006 , A61B6/032 , A61B6/5205 , A61B6/5258 , G06T5/002 , G06T2207/10081 , G06T2211/424
Abstract: High-quality image and low radiation exposure are achieved without increasing man-hours and data amount to be held. A table of iterative correction parameters optimized in the representative imaging conditions is held and an iterative correction parameter optimized in the actual imaging conditions is determined from the iterative correction parameters held in the table. In addition to the parameter table, a reference weight is also held and is reflected to generate the iterative correction parameter for each pixel position.
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公开(公告)号：US20170119335A1
公开(公告)日：2017-05-04
申请号：US15123192
申请日：2015-02-04
Applicant: HITACHI, LTD.
Inventor： Keisuke YAMAKAWA , Shinichi KOJIMA
CPC classification number: A61B6/5258 , A61B6/032 , A61B6/461 , A61B6/467 , A61B6/5205 , G06T11/006 , G06T2211/424
Abstract: This X-ray CT device uses iterative reconstruction to obtain a CT image with the desired noise reduction or X-ray reduction ratio. An iterative approximation reconstruction unit (136) is provided which, from measured projection data obtained by an X-ray detection unit of the X-ray CT device, iteratively reconstructs a CT image in a reconstruction range of a subject, and iteratively corrects the CT image such that calculated projection data, calculated through forward projection of a CT image, is the same as the difference between measured projection data detected by the X-raw detection unit and calculated projection data. The iterative approximation reconstruction unit is provided with a parameter determination unit (151), an iterative correction unit (152), and a table unit (153) which calculates in advance the relation between each parameter used in the iterative reconstruction, and noise reduction or X-ray reduction ratio in the CT image. The parameter determination unit (151) determines the parameters from a calculation table in the table unit (153) depending on the desired reduction ratio.
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Patent Agency Ranking
公开(公告)号：US20170003233A1
公开(公告)日：2017-01-05
申请号：US15114091
申请日：2014-02-26
Applicant: HITACHI, LTD.
Inventor： Akio YONEYAMA , Rika BABA , Keisuke YAMAKAWA
CPC classification number: G01N23/046 , G01N23/04 , G01N23/20 , G01N2223/056 , G01N2223/3306 , G01N2223/419 , G01N2223/423
Abstract: An object of the present invention is to non-destructively obtain, in an X-ray imaging apparatus, a sectional image of a subject with spatial resolution higher than spatial resolution of an image detector. In the present invention, the image detector is two-dimensionally moved with respect to an incident X-ray for each half (180°) rotation of the subject, and a plurality of image groups (CT data sets) is obtained at different positions of the image detector. An image (sinogram) is synthesized from each image group thus obtained, which image is equal to an image obtained with a detector whose pixel size is smaller than the pixel size constituting the above described image detector. From this synthesized image, a sectional image with high spatial resolution is calculated by reconstruction calculation.
Abstract translation: 本发明的目的是在X射线成像设备中非破坏性地获得具有高于图像检测器的空间分辨率的空间分辨率的被摄体的截面图像。 在本发明中，对于被摄体的每半（180°）旋转，图像检测器相对于入射X射线二维移动，并且在不同位置处获得多个图像组（CT数据集） 图像检测器。 从如此获得的每个图像组合成图像（正弦图），该图像等于其像素尺寸小于构成上述图像检测器的像素尺寸的检测器获得的图像。 从该合成图像，通过重建计算来计算具有高空间分辨率的截面图像。
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公开(公告)号：US20170231581A1
公开(公告)日：2017-08-17
申请号：US15503041
申请日：2015-06-15
Applicant: HITACHI, LTD.
Inventor： Xingdong SHENG , Yingjie HAN , Taiga GOTO , Keisuke YAMAKAWA
CPC classification number: A61B6/032 , A61B6/03 , A61B6/5264 , G06T7/70 , G06T11/003 , G06T11/006 , G06T2207/10081 , G06T2207/30004 , G06T2211/424
Abstract: A CT image reconstructing method, a CT image reconstructing device and a CT system are provided for reducing motion artifacts in CT images in case of motion of an object. The CT image reconstructing method reconstructs CT images from projection data obtained by X-ray scanning, including a moving object position detecting step for detecting a position of a moving object in a CT image; a partial angle selecting step for selecting a view point and an angle range according to said position of the moving object and selecting data of partial angles in said projection data according to said view point and said angle range; a partial angle constraint step for generating partial angles constraint conditions according to the data of said partial angles; and an iterative reconstruction step for generating CT images by iterative reconstruction, thereby improving temporal resolution of CT images of moving objects and reducing motion artifacts.
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公开(公告)号：US20170176609A1
公开(公告)日：2017-06-22
申请号：US15325497
申请日：2015-07-23
Applicant: HITACHI, LTD.
Inventor： Yushi TSUBOTA , Shinji KUROKAWA , Keisuke YAMAKAWA , Yasutaka KONNO , Shinichi KOJIMA , Fumito WATANABE
CPC classification number: G01T1/2985 , A61B6/032 , A61B6/4233 , G01N23/046
Abstract: Provided is a technique in an X-ray imaging apparatus for implementing data interpolation approximating an ideal point response trajectory interpolation, along with reducing calculation load. A method is provided to perform interpolation at high speed, in a direction along the point response trajectory. Sinograms are interpolated in advance from measured data, as to representative angles (e.g., 0°, ±30°, ±60°, and 90°) only. When a pixel targeted for back projection is determined at the time of reconstruction, a slope of the point response trajectory is determined as to each view. According to the slope of the trajectory, each representative sinogram is added with weight, whereby interpolation data in association with any angle can be obtained.
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公开(公告)号：US20210027430A1
公开(公告)日：2021-01-28
申请号：US16897768
申请日：2020-06-10
Applicant: Hitachi, Ltd.
Inventor： Mariko YAMAMOTO , Keisuke YAMAKAWA , Isao TAKAHASHI , Taiga GOTOU , Hisashi TAKAHASHI
Abstract: Noise is reduced for a medical image for which noise cannot be quantified by a general-purpose image quality evaluation index. An image processor has a preprocessor that generates input images including an original image and one or more images with reduced noise compared with the original image; and a noise reduction processor outputs an image, which is obtained by reducing noise from the original image based on the input images, by applying a learned network. The learned network used in the noise reduction processor is constructed by performing deep learning using a plurality of learning sets in which one or more of a medical image including noise, a noise-reduced image obtained by performing noise reduction processing on the medical image, and an intermediate image obtained during the noise reduction processing are input images and a correct image is obtained based on the input images an output image.
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公开(公告)号：US20180220979A1
公开(公告)日：2018-08-09
申请号：US15504827
申请日：2015-08-06
Applicant: Hitachi, Ltd.
Inventor： Shinichi KOJIMA , Keisuke YAMAKAWA
CPC classification number: A61B6/4241 , A61B6/032 , A61B6/463 , A61B6/542
Abstract: Provided is a photon counting CT device for estimating an exposure dose to a subject, precisely in a simple configuration, irrespective of a spectrum shape of X-rays being applied. An exposure dose derived from the X-rays with predetermined intensity is obtained in every energy range provided in advance, and held as exposure per band data. When an imaging condition is provided, X-rays are applied in accordance with the imaging condition thus provided, and a photon count (intensity) of the incident X-rays as to each energy range is obtained, in the shape of spectrum of the X-rays applied to a detector without placing the subject. The intensity of the incident X-rays is multiplied by the exposure per band, and the results as to all the energy ranges are added up. Accordingly, the exposure dose caused by the X-rays being applied in accordance with the provided imaging condition is estimated.
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