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公开(公告)号：US5216601A
公开(公告)日：1993-06-01
申请号：US440530
申请日：1989-11-22
申请人： Carl R. Crawford , Kevin F. King
发明人： Carl R. Crawford , Kevin F. King
CPC分类号： G06T11/005 , A61B6/027
摘要： A method of reducing image artifacts in images acquired with fan beam, helical scanning, tomographic imaging systems rebins the fan beam data into parallel beam projection sets. Data is spliced from first areas of the parallel beam projection data to second areas to create a set of 2.pi. radians of complete projection data. The 2.pi. of projection data is divided into half scans which are interpolated and extrapolated to produce a new projection set at the slice plane with reduced helical offset error. A feathering function is used to blend the discontinuities in the interpolation and extrapolation weights to prevent streak image artifacts.
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2.发明授权Method for reducing patient translation artifacts in tomographic imaging 失效用于减少患者转录成像在TOMOGRAPHIC成像中的方法
公开(公告)号：US5170346A
公开(公告)日：1992-12-08
申请号：US440531
申请日：1989-11-22
申请人： Carl R. Crawford , Kevin F. King
发明人： Carl R. Crawford , Kevin F. King
CPC分类号： A61B6/032 , A61B6/027 , G06T11/005
摘要： A method of reducing artifacts in images acquired with fan beam, helical scanning, tomographic imaging systems, applies a weighting function to the tomographic projection set. The weighting function reduces the contribution to the final image of projection data with large helical offset. Other redundant data within the projection set is increased in weight by the weighting function to prevent image artifacts from the weighting. In one embodiment, the projection set is centered on the slice plane to avoid discontinuities in the projection data caused by the weighting functions.
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公开(公告)号：US5361291A
公开(公告)日：1994-11-01
申请号：US796113
申请日：1991-11-20
申请人： Thomas L. Toth , Carl R. Crawford , Kevin F. King
发明人： Thomas L. Toth , Carl R. Crawford , Kevin F. King
IPC分类号： A61B6/03 , G06T11/00 , G01N23/083
CPC分类号： A61B6/032 , A61B6/4021 , G06T11/005 , Y10S378/901
摘要： A CT apparatus for reducing aliasing in reconstructed images uses an x-ray tube with a translatable focal spot to double the spatial sampling rate, over that achieved by a conventional CT machine. Radial resolution artifacts in the image, identified to the "bleeding through" of previous samples from different focal spot positions into the present sample are removed by a convolution process employing the inverse of the detector transfer function. Timing of the data sampling with respect to the changing of the wobble positions is also employed to minimize the bleed through and to improve signal-to-noise ratio.
摘要翻译： 用于减少重建图像中的混叠的CT装置使用具有可平移焦点的X射线管将空间采样速率提高一倍，超过常规CT机实现的。 通过使用检测器传递函数的倒数的卷积处理，去除了识别为从先前样品从不同焦斑位置到本样品的“渗透”的图像中的径向分辨率伪像。 关于摆动位置改变的数据采样的定时也用于使渗流最小化并提高信噪比。
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4.发明授权Computed tomographic image reconstruction method for helical scanning using interpolation of partial scans for image construction 失效用于图像构建部分扫描插值的螺旋扫描的计算机断层图像重建方法
公开(公告)号：US5270923A
公开(公告)日：1993-12-14
申请号：US430372
申请日：1989-11-02
CPC分类号： A61B6/032 , A61B6/027 , G06T11/005
摘要： A method of reducing image artifacts in images acquired with fan beam, helical scanning, tomographic imaging systems uses half scans of less than 360.degree. of projection data of an imaged object on each side of the slice plane being imaged. The half scans are weighted with half scan weighting factors to compensate for redundant data and are weighted with helical scanning weighting factors to interpolate the half scans projection data to projection data at the slice plane. The imaged object may be moved one slice thickness for each 360.degree. of scanning so that the half scans are concentrated closer to the slice plane thereby reducing interpolation errors. Alternatively, for a series of slice images, the imaged object may be moved one slice thickness for each half scan to reduce average slice acquisition time.
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5.发明授权Method for helical scanning with a stationary detector using rebinning and splicing to create detector vertex projection sets 失效使用重新启动和分离创建检测器VERTEX投影机的静态检测器进行螺旋扫描的方法
公开(公告)号：US5208746A
公开(公告)日：1993-05-04
申请号：US440566
申请日：1989-11-22
申请人： Kevin F. King , Carl R. Crawford
发明人： Kevin F. King , Carl R. Crawford
CPC分类号： G06T11/005 , A61B6/027
摘要： A method of reducing image helical scanning artifacts in fourth generation computed tomography imaging systems, rebins 360.degree. of projection data into two half scans. The data of the half scans is spliced so as to create 360.degree. of contiguous detector vertex projections. A weighting function is applied to the two half scans and they are reconstructed to an image per conventional reconstruction methods. The weighting functions provide effective interpolation and extrapolation of the half scan data to a slice plane centered in the projection data. In one embodiment, the weighting functions are feathered with a cubic function to remove weighting induced image artifacts.
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公开(公告)号：US5090037A
公开(公告)日：1992-02-18
申请号：US615514
申请日：1990-11-19
申请人： Thomas L. Toth , Kevin F. King , Carl R. Crawford
发明人： Thomas L. Toth , Kevin F. King , Carl R. Crawford
摘要： A CT apparatus reduces errors in projection data acquired in helical scanning. The imaged object moves concurrently along a translation axis and the x-ray beam is periodically translated with the imaged object so as to subtend a single predetermined volume element during the acquisition of one projection set of data for a first slice. The x-ray beam then returns to its starting position and tracks a second predetermined volume element within a next slice. The x-ray beam may be translated by moving the focal point or a collimator or a combination of both.
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7.发明授权Compensation of computed tomography data for X-ray detector afterglow artifacts 失效计算机断层摄影数据补偿X射线探测器余辉假象
公开(公告)号：US5265013A
公开(公告)日：1993-11-23
申请号：US615777
申请日：1990-11-19
申请人： Kevin F. King , Carl R. Crawford
发明人： Kevin F. King , Carl R. Crawford
CPC分类号： G06T11/005 , Y10S128/922
摘要： An x-ray CT system has a detector which revolves about the object being imaged to acquire attenuation data from many different angles through a range of at least 180.degree.. The response of the detector has a time lag which as the detector revolves tends to blur the attenuation data. The acquired data is compensated for the resolution degradation by convolving the data with a function that is the inverse of a response function of the detector. An image can be reconstructed from this compensated data. However, this compensation process tends to reintroduce noise that was reduced by the blurring. As a result, a modified version of the detector response function is applied to the compensated data to reduce the noise without degrading the image resolution to an unacceptable level.
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公开(公告)号：US5233518A
公开(公告)日：1993-08-03
申请号：US435980
申请日：1989-11-13
申请人： Kevin F. King , Carl R. Crawford
发明人： Kevin F. King , Carl R. Crawford
CPC分类号： G06T11/005 , A61B6/027 , A61B6/032
摘要： A method of reducing image helical scanning; artifacts in computed tomography imaging systems divides 360.degree. of projection data into two half scans. Separate weighting functions are applied to the two half scans and they are reconstructed to an image per conventional reconstruction methods. The weighting functions provide effective interpolation and extrapolation of the half scan data to a slice plane centered in the projection data. In one embodiment, the weighting functions are feathered with a cubic function to remove weighting induced image artifacts.
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9.发明授权Helical scanning computed tomography apparatus with constrained tracking of the x-ray source 失效螺旋扫描计算机断层摄影装置，具有x射线源的约束跟踪
公开(公告)号：US5224136A
公开(公告)日：1993-06-29
申请号：US906805
申请日：1992-06-30
申请人： Thomas L. Toth , Kevin F. King , Carl R. Crawford
发明人： Thomas L. Toth , Kevin F. King , Carl R. Crawford
摘要： A CT apparatus reduces errors in projection data acquired in helical scanning. The imaged object moves concurrently along a translation axis and the x-ray beam is periodically translated with the imaged object so as to subtend a single predetermined volume element during the acquisition of one projection set of data for a first slice. The x-ray beam then returns to its starting position and tracks a second predetermined volume element within a next slice. The x-ray beam may be translated by moving the focal point or a collimator or a combination of both. Helical scans with a pitch requiring sweeping of the x-ray beam beyond the detector limits are accommodated by limiting the sweep to a lessor compliance distance. The angular rate of the sweep is held constant within this compliance distance during the sweep.
摘要翻译： CT装置减少了在螺旋扫描中获取的投影数据中的误差。 成像对象沿着平移轴同时移动，并且x射线束与成像对象周期性地平移，以便在获取第一切片的一个投影数据集期间对准单个预定体积元素。 然后x射线束返回到其起始位置，并在下一个切片内跟踪第二预定体积元素。 可以通过移动焦点或准直器或两者的组合来平移x射线束。 通过将扫描限制到出租人合规距离，通过需要扫描X射线束超过检测器极限的螺距的螺旋扫描得到适应。 在扫描过程中扫描的角速度保持恒定在该顺应距离内。
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10.发明授权Method of and system for classifying objects using local distributions of multi-energy computed tomography images 有权使用多能计算机断层摄影图像的局部分布对物体进行分类的方法和系统公开(公告)号：US07801348B2
公开(公告)日：2010-09-21
申请号：US11183471
申请日：2005-07-18
IPC分类号： G06K9/00
CPC分类号： G06K9/00771 , G01V5/0041 , G01V5/005
摘要： A method of and a system for identifying objects using local distribution features from multi-energy CT images are provided. The multi-energy CT images include a CT image, which approximates density measurements of scanned objects, and a Z image, which approximates effective atomic number measurements of scanned objects. The local distribution features are first and second order statistics of the local distributions of the density and atomic number measurements of different portions of a segmented object. The local distributions are the magnitude images of the first order derivative of the CT image and the Z image. Each segmented object is also divided into different portions to provide geometrical information for discrimination. The method comprises preprocessing the CT and Z images, segmenting images into objects, computing local distributions of the CT and Z images, computing local distribution histograms, computing local distribution features from the said local distribution histograms, classifying objects based on the local distribution features.
摘要翻译： 提供了一种使用多能CT图像的局部分布特征识别物体的方法和系统。 多能CT图像包括近似于扫描对象的密度测量的CT图像和近似有效的扫描对象原子数测量的Z图像。 局部分布特征是分段对象的不同部分的密度和原子序数测量的局部分布的一阶和二阶统计。 局部分布是CT图像和Z图像的一阶导数的幅度图像。 每个分段对象也被分成不同的部分以提供用于辨别的几何信息。 该方法包括预处理CT和Z图像，将图像分割成对象，计算CT和Z图像的局部分布，计算局部分布直方图，从所述局部分布直方图计算局部分布特征，根据局部分布特征对对象进行分类。
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