公开(公告)号：US06195444B1

公开(公告)日：2001-02-27

申请号：US09228380

申请日：1999-01-12

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

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

IPC分类号： G06K900

CPC分类号： G06K9/00771 ,  G06K2209/09

摘要： A method and apparatus for detecting concealed objects in computed tomography data are disclosed. Sheet-shaped objects such as sheet explosives can be detected by a CT scanning system, in particular, a CT baggage scanning system. The invention analyzes CT voxels in a subregion in proximity to the sheet object to determine if the sheet object is concealed in an electronic device or is “sandwiched” within an item such as a book or magazine. To detect electronic concealment, the number of voxels in a subregion that contains the object having a density above a predetermined threshold is counted and the ratio of that number of voxels to the number of object voxels is computed. If the ratio exceeds a threshold, then it is concluded that the object is concealed in electronics. In response, the CT scanning system can alter discrimination parameters to allow the object to be classified as a threat. For “sandwich” concealment, layers on opposite sides of a sheet object are examined. The mean and standard deviation of density values for the voxels are computed. Where the mean density exceeds a predetermined threshold and the standard deviation is below a different threshold, for at least one of the layers, then it is concluded that the sheet object is sandwiched within an innocuous object such as a magazine or a book.

摘要翻译： 公开了一种用于检测计算机断层摄影数据中的隐藏对象的方法和装置。 CT扫描系统，特别是CT行李扫描系统可以检测片状物体，如片状炸药。 本发明分析在片材对象附近的子区域中的CT体素，以确定片材物体是否被隐藏在电子设备中，或者被“夹在”诸如书籍或杂志的物品内。 为了检测电子隐藏，对包含密度高于预定阈值的对象的子区域中的体素数进行计数，并计算该体素数与对象体素数之比。 如果比值超过阈值，则得出结论，该物体被隐藏在电子设备中。 作为响应，CT扫描系统可以改变辨别参数以允许对象被分类为威胁。 对于“三明治”隐蔽，检查片材对象的相对侧上的层。 计算体素密度值的平均值和标准偏差。 在平均密度超过预定阈值并且标准偏差低于不同阈值的情况下，对于至少一个层，则得出结论，片材物体被夹在诸如杂志或书籍的无害物体内。

公开(公告)号：US6128365A

公开(公告)日：2000-10-03

申请号：US22060

申请日：1998-02-11

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

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

IPC分类号： G01N23/04

CPC分类号： G06K9/00771 ,  G06K2209/09 ,  Y10S378/901

摘要： Sheet-shaped objects can be detected by analyzing a neighborhood of voxels surrounding a test voxel. If the density is sufficiently different, then the 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. 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. A dilation function can then be performed to replace surface voxels. A corrected mass can be compared to mass thresholds. Bulk objects can be detected by a modified morphological connected components labeling (CCL) approach. A merging process can be used to reconnect related items. The system can also identify objects that contain liquids. The object detection rate and false alarm rate can be adjusted by adjusting individual object detection rates and/or false alarm rates.

摘要翻译： 可以通过分析围绕测试体素的体素的邻域来检测片状物体。 如果密度充分不同，则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。 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，以便在检测到床单后将它们组合到对象中。 然后可以执行扩张功能来代替表面体素。 可以将校正的质量与质量阈值进行比较。 大量物体可以通过修改后的形态连接元件标记（CCL）方法进行检测。 合并过程可用于重新连接相关项目。 系统还可以识别含有液体的物体。 可以通过调整个别物体检测率和/或误报率来调整物体检测率和误报率。

公开(公告)号：US6078642A

公开(公告)日：2000-06-20

申请号：US21889

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： G01N23/04

CPC分类号： G06K9/00771 ,  G06K2209/09

摘要： A method and apparatus for detecting and classifying objects in computed tomography (CT) data are disclosed. A connectivity process can be applied to voxels in the data to combine them into objects. 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： 公开了一种用于在计算机断层摄影（CT）数据中检测和分类对象的方法和装置。 连接过程可以应用于数据中的体素，以将它们组合成对象。 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：US6076400A

公开(公告)日：2000-06-20

申请号：US21782

申请日：1998-02-11

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

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

IPC分类号： G01N9/02

CPC分类号： G06K9/00771 ,  G06K2209/09

摘要： A method and apparatus for detecting objects in computed tomography (CT) data are disclosed. Sheet-shaped objects such as sheet explosives can be detected by 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. Bulk objects can be detected by a modified morphological connected components labeling (CCL) approach which performs a series of erosion and dilation steps to separate adjacent objects in the data such that they can be individually labeled and analyzed. A merging process can be used to reconnect related items, such as multiple sticks, that were separated during an erosion step. The merging process allows multiple objects that would individually pass as non-threat items to be combined into a single item that is correctly classified as a threat. The system can also identify objects that contain liquids, if desired. The process of the invention can be carried out in multiple stages. The overall system performance, including overall object detection rate and false alarm rate, can be adjusted by adjusting individual object detection rates and/or false alarm rates.

公开(公告)号：US6026171A

公开(公告)日：2000-02-15

申请号：US22064

申请日：1998-02-11

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

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

IPC分类号： A61B6/00 ,  G01N23/00 ,  G01Q80/00 ,  G01Q90/00 ,  G01T1/29 ,  G01V5/00 ,  G06K9/00

CPC分类号： G01V5/005 ,  G01T1/2985 ,  G06K9/00771 ,  G06K2209/09

摘要： A method and apparatus for detecting objects in computed tomography (CT) data are shown. Specifically, the system can identify objects that contain liquids, if desired. A subregion that encloses an object is defined, and a top surface of the subregion is identified. Volume elements at the surfaces of the object are identified. If a ratio of top surface volume elements to the total number of surface volume elements is determined. If that ratio exceeds a predetermined threshold, then the object can be identified as including a liquid.

摘要翻译： 示出了用于在计算机断层摄影（CT）数据中检测物体的方法和装置。 具体来说，如果需要，系统可以识别含有液体的物体。 定义包围对象的子区域，并且识别该子区域的顶表面。 识别物体表面的体积元素。 如果确定顶表面体积元素与表面体积元素总数之比。 如果该比例超过预定阈值，则可以将该物体识别为包括液体。

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

IPC分类号： A61B6/03 ,  G06F17/10 ,  G06T1/00 ,  G06T11/00 ,  G06F15/00

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.

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

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

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.

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

IPC分类号： G21K1/04 ,  G21K5/10

CPC分类号： G21K5/10 ,  A61B6/027 ,  G21K1/04 ,  G21K1/043

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。

公开(公告)号：US4709333A

公开(公告)日：1987-11-24

申请号：US816013

申请日：1986-01-03

申请人： Carl R. Crawford

发明人： Carl R. Crawford

IPC分类号： G06T11/00 ,  G06F15/42

CPC分类号： G06T11/005 ,  A61B6/5258 ,  Y10S378/901

摘要： Method and apparatus for producing CT images in which localized regions ("rub-out" regions) of the original object are not reproduced in order to eliminate artifacts generated by objects within those regions. An operator defines rub-out regions encompassing objects to be removed. For each projection, the rub-out regions of the object are determined and then merged together. A baseline is calculated for each modified rub-out region. That information is then utilized to modify the projection set, in effect eliminating the object from the set. The modified projection set is then used to create a reconstructed image in the normal way.

摘要翻译： 用于产生CT图像的方法和装置，其中不再现原始对象的局部区域（“擦除”区域）），以便消除这些区域内的对象产生的伪影。 操作员定义包含要删除的对象的擦除区域。 对于每个投影，确定对象的擦除区域，然后合并在一起。 为每个修改的擦除区域计算基线。 然后利用该信息来修改投影集，实际上从集合中消除了对象。 然后使用修改的投影集以正常方式创建重建图像。

公开(公告)号：US4636952A

公开(公告)日：1987-01-13

申请号：US677560

申请日：1984-12-03

申请人： Carl R. Crawford

发明人： Carl R. Crawford

IPC分类号： G06T11/00 ,  G06F15/42

CPC分类号： G06T11/005 ,  G06T2211/421 ,  Y10S378/901

摘要： Image reconstruction in a tomographic scanning system using a fan beam of radiation and a curved equi-angular detector array is facilitated by mapping signals from the curved array into a virtual equi-spaced planar detector array. Back projection image reconstruction algorithms are simplified by using the signals from the virtual equi-spaced planar array.

摘要翻译： 通过将来自弯曲阵列的信号映射成虚拟的等间隔平面检测器阵列，便于使用辐射扇形光束和弯曲等角度检测器阵列的断层扫描系统中的图像重建。 通过使用来自虚拟等间隔平面阵列的信号来简化背投影图像重构算法。