公开(公告)号：US07190757B2

公开(公告)日：2007-03-13

申请号：US10850910

申请日：2004-05-21

申请人： Zhengrong Ying ,  Ram Naidu ,  Sergey Simanovsky ,  Carl R. Crawford

发明人： Zhengrong Ying ,  Ram Naidu ,  Sergey Simanovsky ,  Carl R. Crawford

IPC分类号： A61B6/00

CPC分类号： G01N23/046 ,  G01N2223/419

摘要： A method of and a system for computing Z (effective atomic number) images from projection data are provided, wherein the projections are acquired using at least two x-ray spectra for a set of scanned objects, including a set of low energy projections and a set of high energy projections; the method comprises decomposing the low energy projections and high energy projections into photoelectric projections, reconstructing the photoelectric projections into photoelectric images, reconstructing one of the two sets of projections into CT images, and computing Z images from the CT images and the photoelectric images with parameters obtained from a calibration procedure.

摘要翻译： 提供了一种用于从投影数据计算Z（有效原子序号）图像的方法和系统，其中使用用于一组扫描对象的至少两个X射线光谱来获取投影，包括一组低能量投影和 一套高能量投影; 该方法包括将低能量投影和高能量投影分解为光电投影，将光电投影重建为光电图像，将两组投影中的一个重建为CT图像，并从CT图像和光电图像中计算Z图像 从校准程序获得。

公开(公告)号：US06317509B1

公开(公告)日：2001-11-13

申请号：US09022059

申请日：1998-02-11

申请人： Sergey Simanovsky ,  Ibrahim M. Bechwati ,  Muzaffer Hiraoglu ,  Carl R. Crawford

发明人： Sergey Simanovsky ,  Ibrahim M. Bechwati ,  Muzaffer Hiraoglu ,  Carl R. Crawford

IPC分类号： G06K900

CPC分类号： G01V5/005 ,  G01N33/22 ,  G06K9/00771 ,  G06K2209/09

摘要： A method and apparatus detects sheet explosives in computed tomography (CT) data. In particular, sheet-shaped objects such as sheet explosives can be discriminated from other object shapes and detected. The detection includes analyzing a neighborhood of voxels surrounding a test voxel. If the density of the test voxel is sufficiently different from the mean density of the neighboring voxels, then it is concluded that the test voxel is associated with a sheet object. Sheet objects can also be detected by eroding the CT data so as to eliminate voxels associated with thin objects. Remaining objects are then subtracted from the original data, leaving only thin sheet-shaped objects. Erosion of the data can be performed by identifying a neighborhood of voxels surrounding a voxel of interest. If the number of voxels having densities below a predetermined threshold exceeds a predetermined number, then it is assumed that the test voxel is a surface voxel and is removed from the object. A connectivity process can be applied to voxels to combine them into objects after sheets are detected to prevent sheets from being inadvertently removed from the data by erosion. A dilation function can then be performed on the eroded object to replace surface voxels removed by erosion. A corrected mass using the mean eroded density of the object can be computed and compared to mass thresholds to classify the object as to whether it poses a threat. Multiple mass thresholds can be used, each of which is associated with a particular density range based on the density of an expected threat object.

摘要翻译： 计算机断层摄影（CT）数据中的方法和装置检测片状炸药。 特别地，片状物体如片状炸药可以与其他物体形状区分开来并进行检测。 检测包括分析围绕测试体素的体素的邻域。 如果测试体素的密度与相邻体元的平均密度有很大的不同，则可以得出结论，测试体素与片材物体相关联。 也可以通过侵蚀CT数据来检测片材物体，以消除与薄物体相关联的体素。 然后从原始数据中减去剩余对象，只留下薄片状物体。 可以通过识别感兴趣的体素周围的体素的邻域来执行数据的侵蚀。 如果具有低于预定阈值的密度的体素的数量超过预定数量，则假设测试体素是表面体素并且从对象中移除。 可以将连接过程应用于体素，以便在检测到页面之后将其组合到对象中，以防止纸张被侵蚀从而无意中从数据中移除。 然后可以对侵蚀的物体执行扩张功能，以取代被侵蚀除去的表面体素。 可以计算使用对象的平均侵蚀密度的校正质量，并将其与质量阈值进行比较，以对对象是否构成威胁进行分类。 可以使用多个质量阈值，每个质量阈值基于预期威胁对象的密度与特定密度范围相关联。

公开(公告)号：US5970113A

公开(公告)日：1999-10-19

申请号：US948928

申请日：1997-10-10

申请人： Carl R. Crawford ,  Hans J. Weedon ,  Christopher C. Ruth

发明人： Carl R. Crawford ,  Hans J. Weedon ,  Christopher C. Ruth

IPC分类号： G01V5/00 ,  G01N23/00

CPC分类号： G01V5/005

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：US5887047A

公开(公告)日：1999-03-23

申请号：US948697

申请日：1997-10-10

申请人： Eric M. Bailey ,  Carl R. Crawford ,  Alexander I. Greenberg ,  Christopher C. Ruth

发明人： Eric M. Bailey ,  Carl R. Crawford ,  Alexander I. Greenberg ,  Christopher C. Ruth

IPC分类号： A61B6/03 ,  G01N23/04 ,  G06T15/00

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

摘要： A nutating slice CT image reconstruction apparatus and method generates a set of projection data using helical cone-beam scanning. The three-dimensional projection data is used to reconstruct a series of planar image slices. The slices are selected such that they define a tilt angle and a rotation angle with respect to the longitudinal axes of the object being scanned. Successive slices have equal tilt angles but changing rotation angles such that normal axes of successive slices define a nutation and precession about the longitudinal axis of the object. Projection data for the tilted slices are formed of selected one-dimensional fan-beam data. As such, the projection data can be applied to conventional two-dimensional reconstruction approaches to generate an image. The projection data can also be used to generate two-dimensional projection images at one or more stationary projection angles through an object being scanned. The nutation or tilt of image volume elements can be compensated for to provide a more accurate image and more accurate target assessment such as accurate total mass determination. A parallel processing architecture can be used to generate and process the nutated slices with improved efficiency.

摘要翻译： 章动切片CT图像重建装置和方法使用螺旋锥束扫描产生一组投影数据。 三维投影数据用于重建一系列平面图像切片。 切片被选择为使得它们相对于被扫描物体的纵向轴线限定倾斜角度和旋转角度。 连续切片具有相等的倾斜角度，但是改变旋转角度，使得连续切片的法线定义关于物体的纵向轴线的章动和进动。 倾斜切片的投影数据由选定的一维扇形光束数据形成。 因此，投影数据可以应用于常规的二维重建方法以产生图像。 投影数据还可用于通过被扫描物体在一个或多个固定投影角度产生二维投影图像。 可以补偿图像体积元件的章动或倾斜，以提供更准确的图像和更准确的目标评估，例如准确的总质量确定。 可以使用并行处理架构来提高效率来生成和处理章程切片。

公开(公告)号：US5396528A

公开(公告)日：1995-03-07

申请号：US723361

申请日：1991-06-28

申请人： Hui Hu ,  Carl R. Crawford ,  Armin H. Pfoh ,  Jiang Hsieh

发明人： Hui Hu ,  Carl R. Crawford ,  Armin H. Pfoh ,  Jiang Hsieh

IPC分类号： A61B6/03 ,  G01N23/04 ,  G01N23/083

CPC分类号： A61B6/032 ,  A61B6/4085 ,  Y10S378/901

摘要： A CT apparatus employing a cone beam of x-rays reduces image artifacts by employing full as opposed to half scans of less than 360.degree.. The present invention recognizes that rays of a cone beam that cross the imaging plane are not redundant with opposing rays in the scan, as is the case with the rays within the imaging plane. In a second embodiment, half scans of less than 360.degree. are obtained using in-plane and cross-plane rays of the cone beam and the data from the in-plane rays is used to estimate the missing data from that collected with the cross-plane rays.

摘要翻译： 使用X射线锥形束的CT装置通过采用与小于360度的半扫描相反的方式来减少图像伪影。 本发明认识到，如同成像平面内的射线的情况一样，穿过成像平面的锥形束的射线在扫描中与相对的射线不是冗余的。 在第二实施例中，使用锥形束的平面内和平面光线获得小于360°的半扫描，并且使用来自平面内射线的数据来估计从交叉点收集的数据中丢失的数据， 飞机射线

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。