公开(公告)号：US20060023844A1

公开(公告)日：2006-02-02

申请号：US10899775

申请日：2004-07-27

申请人： Ram Naidu ,  Zhengrong Ying ,  Chitra Subramanian ,  Sergey Simanovsky ,  Carl Crawford

发明人： Ram Naidu ,  Zhengrong Ying ,  Chitra Subramanian ,  Sergey Simanovsky ,  Carl Crawford

IPC分类号： H05G1/00

CPC分类号： G01N23/046 ,  G01N2223/419 ,  G01T1/185

摘要： A method of and a system for spectral correction in multi-energy computed tomography are provided to correct reconstructed images, including high-energy CT images and Z (effective atomic number) images, for spectral variations, which include time variations on a scanner due to HVPS drift and scanner to scanner variations due to the beamline component differences. The method uses a copper filter mounted on the detector array for tracking the spectral changes. The method comprises: generating copper ratios; computing working air tables; calculating scales and offsets; and correcting high-energy CT images and Z images using calculated scales and offsets. The method further includes an off-line calibration procedure to generate necessary parameters for the online correction.

摘要翻译： 提供了一种用于多能量计算机断层摄影中的光谱校正的方法和系统，用于校正重建图像，包括高能CT图像和Z（有效原子序数）图像，用于光谱变化，包括扫描仪上的时间变化，由于 HVPS漂移和扫描仪由于束线分量差异而导致扫描仪变化。 该方法使用安装在检测器阵列上的铜过滤器来跟踪光谱变化。 该方法包括：产生铜比; 计算工作台面; 计算比例和偏移量; 并使用计算的比例和偏移校正高能CT图像和Z图像。 该方法还包括离线校准程序以产生用于在线校正的必要参数。

公开(公告)号：US07224763B2

公开(公告)日：2007-05-29

申请号：US10899775

申请日：2004-07-27

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

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

IPC分类号： G01N23/00

CPC分类号： G01N23/046 ,  G01N2223/419 ,  G01T1/185

摘要： A method of and a system for spectral correction in multi-energy computed tomography are provided to correct reconstructed images, including high-energy CT images and Z (effective atomic number) images, for spectral variations, which include time variations on a scanner due to HVPS drift and scanner to scanner variations due to the beamline component differences. The method uses a copper filter mounted on the detector array for tracking the spectral changes. The method comprises: generating copper ratios; computing working air tables; calculating scales and offsets; and correcting high-energy CT images and Z images using calculated scales and offsets. The method further includes an off-line calibration procedure to generate necessary parameters for the online correction.

摘要翻译： 提供了一种用于多能量计算机断层摄影中的光谱校正的方法和系统，用于校正重建图像，包括高能CT图像和Z（有效原子序数）图像，用于光谱变化，包括扫描仪上的时间变化，由于 HVPS漂移和扫描仪由于束线分量差异而导致扫描仪变化。 该方法使用安装在检测器阵列上的铜过滤器来跟踪光谱变化。 该方法包括：产生铜比; 计算工作台面; 计算比例和偏移量; 并使用计算的比例和偏移校正高能CT图像和Z图像。 该方法还包括离线校准程序以产生用于在线校正的必要参数。

公开(公告)号：US20050259781A1

公开(公告)日：2005-11-24

申请号：US10850910

申请日：2004-05-21

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

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

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

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：US20070014472A1

公开(公告)日：2007-01-18

申请号：US11183471

申请日：2005-07-18

申请人： Zhengrong Ying ,  Ram Naidu ,  Sergey Simanovsky ,  Matthew Hirsch ,  Carl Crawford

发明人： Zhengrong Ying ,  Ram Naidu ,  Sergey Simanovsky ,  Matthew Hirsch ,  Carl Crawford

IPC分类号： G06K9/00 ,  G06K9/46

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。

公开(公告)号：US20050271293A1

公开(公告)日：2005-12-08

申请号：US10860984

申请日：2004-06-04

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

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

IPC分类号： G06K9/00

CPC分类号： G06T5/005 ,  G06T5/20 ,  G06T2200/04 ,  G06T2207/10081 ,  G06T2207/30112

摘要： A method of and a system for destreaking the photoelectric image in multi-energy computed tomography are provided, wherein the photoelectric projections are generated from the projection data acquired using at least two x-ray spectra for scanned objects; wherein a neighboring scheme is provided; the method comprises computing the statistics including mean and standard deviation using the neighboring scheme; calculating an upper limit and a lower limit from the computed statistics; detecting outliers in the photoelectric projections using the upper and lower limits; and replacing values of outliers using the upper or lower limit.

摘要翻译： 提供了一种用于在多能计算机断层摄影中破坏光电图像的方法和系统，其中光电投影是从使用扫描对象的至少两个X射线光谱获取的投影数据产生的; 其中提供相邻方案; 该方法包括使用相邻方案计算包括平均值和标准偏差的统计量; 从计算的统计量计算上限和下限; 利用上下限检测光电投影中的异常值; 并使用上限或下限替换异常值的值。

公开(公告)号：US20070031036A1

公开(公告)日：2007-02-08

申请号：US11198360

申请日：2005-08-04

申请人： Ram Naidu ,  Zhengrong Ying ,  Sergey Simanovsky ,  Matthew Hirsch ,  Carl Crawford

发明人： Ram Naidu ,  Zhengrong Ying ,  Sergey Simanovsky ,  Matthew Hirsch ,  Carl Crawford

IPC分类号： G06K9/00

CPC分类号： G01V5/0008

摘要： A method of and a system for identifying objects using histogram segment 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 method comprises: computing a density histogram for each potential threat object; smoothing the density histogram using a low-pass filter; identifying peaks in the smoothed density histogram; assigning a segment to each peak; computing histogram segment features for each segment; classifying each potential threat object into a threat or a non-threat using computed features.

摘要翻译： 提供了一种用于使用来自多能CT图像的直方图段特征来识别对象的方法和系统。 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。 该方法包括：计算每个潜在威胁对象的密度直方图; 使用低通滤波器平滑密度直方图; 识别平滑密度直方图中的峰值; 为每个峰分配一个段; 计算每个段的直方图段特征; 使用计算特征将每个潜在的威胁对象分类为威胁或非威胁。

公开(公告)号：US20050276373A1

公开(公告)日：2005-12-15

申请号：US10853942

申请日：2004-05-26

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

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

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

CPC分类号： G06T11/005 ,  A61B6/032 ,  A61B6/5282 ,  G01N23/046 ,  G01N2223/419 ,  G06T2211/408

摘要： Method of and system for adaptive scatter correction in the absence of scatter detectors in multi-energy computed tomography are provided, wherein input projection data acquired using at least two x-ray spectra for scanned objects may include a set of low energy projections and a set of high energy projections; wherein a low-pass filter of variable size is provided; the method comprises estimating the size of the low-pass filter; computing amounts of scatter; and correcting both sets of projections for scatter. The estimation of low-pass filter size comprises thresholding high energy projections into binary projections; filtering the binary projections; finding the maximum of the filtered binary projections; calculating the low-pass filter size from the found maximum. The computation of amounts of scatter comprises exponentiating input projections; low-pass filtering the exponentiated projections with the estimated filter size; computing the amounts of scatter from the filtered projections.

摘要翻译： 提供了在多能计算机断层摄影中不存​​在散射检测器的自适应散射校正的方法和系统，其中使用至少两个用于扫描对象的X射线光谱获得的输入投影数据可以包括一组低能量投影和一组 的高能量预测; 其中提供可变尺寸的低通滤波器; 该方法包括估计低通滤波器的尺寸; 计算散射量; 并且校正两组用于散射的投影。 低通滤波器尺寸的估计包括将高能量投影阈值化为二进制投影; 过滤二进制投影; 找出滤波后的二进制投影的最大值; 从找到的最大值计算低通滤波器尺寸。 散射量的计算包括指数输入投影; 用估计的滤波器大小对指数投影进行低通滤波; 从过滤的投影计算散射量。

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：US07724866B2

公开(公告)日：2010-05-25

申请号：US11769370

申请日：2007-06-27

申请人： Ram Naidu ,  Basak Ulker Karbeyaz ,  Zhengrong Ying ,  Sergey Simanovsky ,  Matthew Hirsch ,  David Schafer ,  Carl R. Crawford

发明人： Ram Naidu ,  Basak Ulker Karbeyaz ,  Zhengrong Ying ,  Sergey Simanovsky ,  Matthew Hirsch ,  David Schafer ,  Carl R. Crawford

IPC分类号： A61B6/03

CPC分类号： G01V5/005 ,  A61B6/027 ,  G01T1/2985

摘要： A method of and a system for variable pitch CT scanning for baggage screening and variable pitch image reconstruction are disclosed. The method comprises decelerating conveyor belt speed when additional time is needed to render a decision on a complex bag; accelerating conveyor belt speed to its normal speed when decisions are reached on undecided bags; generating cone-beam projection data at variable scanning pitch corresponding to variable conveyor belt speed; computing a tilt angle and a distance offset for each tilted slice using the pitch values at which the cone-beam projection data is acquired for that tilted slice; generating fan-beam projection data for each tilted slice using the tilted angle and the distance offset; generating correction projection data to compensate for the error between the source trajectory and the tilted reconstruction plane; generating the corrected fan-beam projection data by adding the correction projection data to the fan-beam projection data; reconstructing tilted slices using the corrected fan-beam projection data; and interpolating the reconstructed tilted slices into axial slices.

摘要翻译： 公开了用于行李筛选和可变间距图像重构的可变间距CT扫描的方法和系统。 该方法包括在需要额外的时间来对复杂袋子做出决定时减速输送带速度; 加速输送带速度达到正常速度，在未定的袋子上达成决定; 产生对应于可变输送带速度的可变扫描间距的锥形束投影数据; 使用对于该倾斜切片获取锥形束投影数据的间距值来计算每个倾斜切片的倾斜角和距离偏移; 使用倾斜角度和距离偏移量为每个倾斜切片生成扇形投影数据; 产生校正投影数据以补偿源轨迹和倾斜重建平面之间的误差; 通过将校正投影数据添加到扇形投影数据来生成校正的扇形投影数据; 使用校正的扇形束投影数据重建倾斜的切片; 并将重构的倾斜切片内插到轴向切片中。

公开(公告)号：US07474786B2

公开(公告)日：2009-01-06

申请号：US11198360

申请日：2005-08-04

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

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

IPC分类号： G06K9/00

CPC分类号： G01V5/0008

摘要： A method of and a system for identifying objects using histogram segment 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 method comprises: computing a density histogram for each potential threat object; smoothing the density histogram using a low-pass filter; identifying peaks in the smoothed density histogram; assigning a segment to each peak; computing histogram segment features for each segment; classifying each potential threat object into a threat or a non-threat using computed features.

摘要翻译： 提供了一种用于使用来自多能CT图像的直方图段特征来识别对象的方法和系统。 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。 该方法包括：计算每个潜在威胁对象的密度直方图; 使用低通滤波器平滑密度直方图; 识别平滑密度直方图中的峰值; 为每个峰分配一个段; 计算每个段的直方图段特征; 使用计算特征将每个潜在的威胁对象分类为威胁或非威胁。