公开(公告)号：US5251128A

公开(公告)日：1993-10-05

申请号：US615778

申请日：1990-11-19

申请人： Carl R. Crawford

发明人： Carl R. Crawford

IPC分类号： A61B5/113 ,  A61B6/03 ,  G01T1/161 ,  G06T11/00 ,  G06F15/42

CPC分类号： A61B6/589 ,  A61B5/113 ,  A61B5/721 ,  A61B6/032 ,  A61B6/5264 ,  G06T11/005 ,  A61B5/7257 ,  G06T2211/412 ,  G06T2211/421

摘要： An x-ray CT scanner acquires projection data from a series of views during a scan of a patient's chest. Movement of the patient's chest due to respiration is also sensed during the scan and this acquired motion data is employed along with a geometric model of chest motion to calculate factors which correct the acquired projection data and reduce motion artifacts in an image produced by back projecting the acquired projection data.

摘要翻译： X射线CT扫描仪在扫描患者胸部时从一系列视图中获取投影数据。 在扫描期间也感觉到患者胸部因呼吸而发生的运动，并且将所获取的运动数据与胸部运动的几何模型一起使用，以计算校正所获取的投影数据并减少通过反投影产生的图像中的运动伪像的因素 获取投影数据。

公开(公告)号：US5150427A

公开(公告)日：1992-09-22

申请号：US414377

申请日：1989-09-29

申请人： David M. Frazee ,  Carl R. Crawford

发明人： David M. Frazee ,  Carl R. Crawford

IPC分类号： A61B6/03 ,  A61B5/055 ,  G06T15/08 ,  G06T17/00

CPC分类号： G06T17/00

摘要： A method of editing image data produced from reconstructed tomographic data comprises the creation and editing of a bit map with bits corresponding to each data element of the image. The bit map permits faster processing of editing commands. The resultant image is displayed from a boolean combination of the edited bit map and the original data elements. Rapid altering of the boolean combination allows "toggling" of the edited image with an unedited image for clarity. The edited bit map may be used to edit a three dimensional reconstruction by substituting pad values for the image data according to the state of the bit map. The bit map may be altered to track certain editing processes such as connectivity or region growing.

公开(公告)号：US5046003A

公开(公告)日：1991-09-03

申请号：US371332

申请日：1989-06-26

申请人： Carl R. Crawford

发明人： Carl R. Crawford

IPC分类号： A61B5/055 ,  A61B6/03 ,  G06T1/00 ,  G06T3/60

CPC分类号： G06T3/608 ,  A61B6/032 ,  A61B6/027

摘要： A method of reducing image artifacts in tomographic projection imaging systems where the projection data is acquired using continuous gantry motion and using a variable table velocity to transport the imaged object past the rotating gantry. The table velocity is decreased when the projections are being acquired near the slice plane and increased when the projections being acquired are further from the slice plane. The table position is coordinated with the acquisition of projections so that the middle projections of the tomographic projection set are acquired close to the slice plane and the beginning and end projections are acquired when the projections are taken furthest from the slice plane. Interpolation procedures are used to further reduce image artifacts resulting from the taking of projection data at points removed from the slice plane.

摘要翻译： 一种降低断层摄影投影成像系统中的图像伪像的方法，其中使用连续台架运动获取投影数据，并使用可变表速度将成像物体传送通过旋转机架。 当在切片平面附近获取投影时，表速度降低，并且当获取的投影更远离切片平面时，表速度增加。 台面位置与投影的采集协调一致，使得断层投影组的中间投影被接近切片平面，并且当投影被从切片平面取得最远时获取开始和结束投影。 内插程序用于进一步减少由从切片平面移除的点处获取投影数据而导致的图像伪像。

公开(公告)号：US4953087A

公开(公告)日：1990-08-28

申请号：US261532

申请日：1988-10-24

申请人： Carl R. Crawford

发明人： Carl R. Crawford

IPC分类号： G01R33/56 ,  G06T17/00

CPC分类号： G01R33/56 ,  G06T17/00

摘要： Three-dimensional representations of the surface of a structure located in a three-dimensional space are formed from tomographic data collected in a medical diagnostic imaging system. The images include structures of specific interest displayed at a high resolution and adjacent structures to improve the perception of the structures of interest displayed at a low resolution. Total examination time is reduced because the total number of slices needed to form the image is reduced. A plurality of slices of different spacings are obtained and divided into first and second space portions (associated with different slice spacings). An interpolation factor which varies as a function of slice spacing is used in the dividing step to establish selected dimensions of first and second three-dimensional elements. The location of each of the first and second elements is specified as a function of the interpolation factor and the first and second three-dimensional elements which contain a portion of the surface are identified.

摘要翻译： 位于三维空间中的结构的表面的三维表示由收集在医学诊断成像系统中的断层数据形成。 这些图像包括以高分辨率显示的特定兴趣的结构和相邻的结构，以改善以低分辨率显示的兴趣结构的感知。 减少总检查时间，因为减少了形成图像所需的切片总数。 获得多个不同间隔的切片，并将其分成第一和第二空间部分（与不同切片间隔相关联）。 在分割步骤中使用作为切片间隔的函数而变化的内插因子来建立第一和第二三维元素的选定尺寸。 第一和第二元件中的每一个的位置被指定为内插因子的函数，并且识别包含表面的一部分的第一和第二三维元素。

公开(公告)号：US4703424A

公开(公告)日：1987-10-27

申请号：US688486

申请日：1985-01-03

申请人： Grant T. Gullberg ,  Carl R. Crawford

发明人： Grant T. Gullberg ,  Carl R. Crawford

IPC分类号： G01N23/04 ,  A61B6/03 ,  G06T1/00 ,  G06T11/00 ,  G06F15/42

CPC分类号： G06T11/006 ,  A61B6/037 ,  G06T2211/421 ,  Y10S378/901

摘要： Method and means for determining and compensating for a shift in the center of rotation of a fan beam CT reconstruction apparatus. Known reconstruction algorithms for fan beam computed tomography are based on the assumption that the center of rotation of the source or detector is on the midline of the fan. In certain cases due, for example, to machine inaccuracies, the center of rotation can be shifted from the assumed center, and such shift can cause artifacts in the reconstruction. The present invention provides a procedure for estimating the magnitude of the shift and also accommodates for the shift by applying a series of weighting factors to the projection information which are dependent on the magnitude of the shift. The weighted projections are then processed by the usual convolution operation, and the convolved projection sets back projected using a geometry modified to account for the shift. Efficiencies are achieved in that all projection sets can be weighted and convolved before back projection, and existing back projection hardware or software can be used to map the modified projection sets into the pixelized image space.

摘要翻译： 用于确定和补偿扇形束CT重建装置的旋转中心的偏移的方法和装置。 风扇束计算机断层摄影的已知重建算法是基于源或检测器的旋转中心位于风扇中线的假设。 在某些情况下，例如，由于机器不准确，旋转中心可以从假定的中心移位，这种偏移可能会导致重建中的伪像。 本发明提供了一种用于估计移位幅度的过程，并且还通过对依赖于移位幅度的投影信息应用一系列加权因子来适应偏移。 加权投影然后通过通常的卷积运算来处理，并且卷积的投影使用修改的几何来反映投影，以考虑到偏移。 实现效率是，所有投影集可以在反投影之前进行加权和卷积，现有的背投硬件或软件可用于将修改的投影集映射到像素化图像空间中。

公开(公告)号：US5901198A

公开(公告)日：1999-05-04

申请号：US948929

申请日：1997-10-10

申请人： Carl R. Crawford ,  Christopher C. Ruth

发明人： Carl R. Crawford ,  Christopher C. Ruth

IPC分类号： G01V5/00 ,  G01N23/04

CPC分类号： G01V5/005 ,  Y10S378/901

摘要： A method and apparatus for performing CT scans of baggage being carried or loaded onto commercial aircraft are described. The CT baggage scanner of the invention includes numerous features which provide the system with high baggage throughput on the order of seven hundred bags per hour as well as improved image quality and accurate target detection. In one aspect, the scanner includes an adaptive image reconstruction window which identifies data collected from the field of view that are not related to the baggage being scanned. These unrelated data are excluded from the image reconstruction process, resulting in greatly reduced reconstruction time and increased baggage throughput. The invention also includes the capability of performing calibration "air scans" with objects such as the system conveyor in the field of view. Data gathered during the calibration scan are applied to a threshold, and data exceeding the threshold are assumed to be from X-rays that are unobstructed by objects in the field of view and are therefore used to perform the air calibration. The baggage scanner can also analyze scan data to identify shapes of objects, particularly, objects formed in the shape of a sheet. This greatly improves the ability of the system to detect sheet explosives. The system also compensates for detector dark currents and provides dark current offsets which can be dependent upon detector temperature.

摘要翻译： 描述了用于对携带或加载到商用飞机上的行李进行CT扫描的方法和装置。 本发明的CT行李扫描器包括许多特征，为系统提供每小时七百袋的高行李吞吐量，以及改进的图像质量和精确的目标检测。 在一个方面，扫描器包括自适应图像重建窗口，其识别从视场收集的与正在扫描的行李无关的数据。 这些不相关的数据从图像重建过程中排除，从而大大减少了重建时间和增加了行李吞吐量。 本发明还包括在视场中执行诸如系统输送机之类的物体的校准“空气扫描”的能力。 在校准扫描期间收集的数据被应用于阈值，并且超过阈值的数据被假设为来自视场中的物体不受阻挡的X射线，因此用于执行空气校准。 行李扫描器还可以分析扫描数据以识别物体的形状，特别是形成为片状形状的物体。 这大大提高了系统检测片状炸药的能力。 该系统还补偿检测器暗电流，并提供暗电流偏移，这取决于检测器温度。

公开(公告)号：US5828718A

公开(公告)日：1998-10-27

申请号：US829062

申请日：1997-03-31

申请人： Christopher C. Ruth ,  John M. Dobbs ,  Carl R. Crawford

发明人： Christopher C. Ruth ,  John M. Dobbs ,  Carl R. Crawford

IPC分类号： A61B6/03

CPC分类号： A61B6/032 ,  A61B6/027 ,  Y10S378/901

摘要： A system for and method of generating a reconstructed tomographic image is described using an asymmetric detector array during a helical scan. An improved helical weighting system applies a helical halfscan technique to data collected by a symmetric portion of an asymmetric detector system and applies a helical fullscan technique to data collected by an asymmetric portion of the asymmetric detector system. The preferred system comprises an equi-angle interpolator, a streak artifact suppression filter, and an isocenter interpolator that preserve the distinction between even and odd data points in parallel beam projection data.

摘要翻译： 在螺旋扫描期间使用不对称检测器阵列描述了生成重建断层图像的系统和方法。 改进的螺旋加权系统将螺旋半扫描技术应用于由不对称检测器系统的对称部分收集的数据，并对不对称检测器系统的不对称部分收集的数据应用螺旋扫描技术。 优选的系统包括等角内插器，条纹伪影抑制滤波器和等距中心内插器，其保持平行光束投影数据中偶数和奇数数据点之间的区别。

公开(公告)号：US5644610A

公开(公告)日：1997-07-01

申请号：US690810

申请日：1996-08-01

申请人： Carl R. Crawford ,  Christopher C. Ruth ,  Iouri Bachilov ,  Ruvin Deych

发明人： Carl R. Crawford ,  Christopher C. Ruth ,  Iouri Bachilov ,  Ruvin Deych

IPC分类号： G06T11/00 ,  A61B6/03

CPC分类号： G06T11/005 ,  Y10S378/901

摘要： The disclosed CT scanner includes a tomography system for generating data during a scan. The tomography system includes a detector characterized by at least one afterglow amplitude and at least one afterglow time constant, and a sampling device for generating a plurality of samples x.sub.i for all i from zero to MAX minus one of the detector output signal. The scanner also includes a set of N sub-processors for processing the samples x.sub.i, each of the sub-processors being represented by a unique integer q selected from zero to N minus one and receiving only the samples X.sub.iN+q. Each sub-processor includes a device for generating a compensated signal according to a function of at least a portion of the received samples and parameters representative of the afterglow amplitude and the afterglow time constant.

摘要翻译： 所公开的CT扫描仪包括用于在扫描期间产生数据的断层摄影系统。 该断层摄影系统包括一个检测器，其特征在于至少有一个余辉振幅和至少一个余辉时间常数，以及采样装置，用于产生从0到MAX减去检测器输出信号之一的所有i的多个采样xi。 扫描器还包括用于处理样本xi的一组N个子处理器，每个子处理器由从零到N减去一个并且仅接收样本XiN + q的独特整数q表示。 每个子处理器包括用于根据所接收的采样的至少一部分的功能和表示余辉振幅和余辉时间常数的参数产生补偿信号的装置。

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

IPC分类号： G01N23/04 ,  A61B6/03 ,  G06T1/00 ,  G06T11/00

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.

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

IPC分类号： A61B6/03 ,  G21K1/02 ,  G21K5/10

CPC分类号： G21K5/10 ,  A61B6/027 ,  G21K1/025

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.