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41.发明授权
公开(公告)号：US4989142A
公开(公告)日：1991-01-29
申请号：US261534
申请日：1988-10-24
申请人： Carl R. Crawford
发明人： Carl R. Crawford
IPC分类号： G06T5/00
CPC分类号： G06T5/006
摘要： Three-dimensional images are formed from tomographic data collected such that each two-dimensional slice is tilted with respect to the transverse slice direction. Geometric distortion in the reconstructed 3-D image caused by the slice tilt is removed either during extraction of the 3-D surface from the tomographic data or during rendering of the final surface using a matrix transformation.
摘要翻译： 三维图像由收集的断层数据形成，使得每个二维切片相对于横向切片方向倾斜。 在从层析成像数据提取3-D表面或者在使用矩阵变换渲染最终表面期间，都可以去除由切片倾斜引起的重建的3D图像中的几何失真。
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42.发明授权Three-dimensional images obtained from tomographic data using a variable threshold 失效使用可变阈值从断层数据获得的三维图像
公开(公告)号：US4914589A
公开(公告)日：1990-04-03
申请号：US261533
申请日：1988-10-24
申请人： Carl R. Crawford
发明人： Carl R. Crawford
CPC分类号： G06T11/008 , G01R33/563 , G01R33/56
摘要： Three-dimensional images are formed from tomographic data collected in a medical diagnostic imaging system. The images include structures of specific interest having voxel densities not confined to a single, exclusive area of the image histogram. A variable threshold dependent on the particular voxel locations is used in extracting the 3-D surface definition in order to eliminate partial volume artifacts in the 3-D image.
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43.发明授权
公开(公告)号：US4868748A
公开(公告)日：1989-09-19
申请号：US125426
申请日：1987-11-25
IPC分类号： G01N23/04 , A61B5/055 , A61B6/03 , A61B8/14 , G01N29/06 , G01R33/32 , G06T1/00 , G06T1/20 , G06T15/08 , G06T17/00
CPC分类号： G06T17/005 , G06T1/20 , G06T17/00
摘要： Three-dimensional objects within a tomographic data-base are extracted for viewing by comparing the tomographic data to a predetermined threshold or range defining the object boundaries. A surface extraction method is structured so as to allow for several vector operations, thus adapting the method for implementation using an array processor.
摘要翻译： 通过将断层摄影数据与限定对象边界的预定阈值或范围进行比较，提取层析数据库内的三维物体进行观察。 表面提取方法被构造成允许几个向量操作，从而使用阵列处理器来适应实现方法。
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公开(公告)号：US4606004A
公开(公告)日：1986-08-12
申请号：US591730
申请日：1984-03-21
CPC分类号： G06T11/005 , A61B6/5258 , Y10S378/901
摘要： Apparatus for reduction of filtration truncation errors caused by convolving a plurality of input signals, such as line-integral projection data obtained in a computerized tomography (CT) scan of an object, with a common kernel function in a finite precision machine using Fourier transform techniques. The resulting convolved output signals contain correlated noise which, in the case of reconstructed CT images, manifests itself as structured noise in the form of rings and center spots in the image. The correlated noise can be reduced by randomly shifting the data prior to convolving it. The random shift can be achieved by a rotational permutation scheme. Another scheme for shifting the data is to prepend or append zeros to the data by using a random number generator or a deterministic function.
摘要翻译： 用于减少由使用傅里叶变换技术的有限精密机器中的公共核心功能卷积多个输入信号（例如在对象的计算机断层摄影（CT）扫描中获得的线积分投影数据）引起的过滤截断错误的装置 。 所产生的卷积输出信号包含相关噪声，其在重建的CT图像的情况下，以图像中环和中心点的形式表现为结构化噪声。 相关噪声可以通过在卷积之前随机移位数据来减少。 随机移位可以通过旋转置换方案来实现。 用于移动数据的另一种方案是通过使用随机数生成器或确定性函数来将零添加到数据中。
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公开(公告)号：US06850587B1
公开(公告)日：2005-02-01
申请号：US10279412
申请日：2002-10-24
CPC分类号： A61B6/032 , A61B6/027 , A61B6/488 , G06T11/005 , G06T2211/432 , Y10S378/901
摘要： A method of reconstructing a three-dimensional image from a set of X-ray projections generated by a scanning system, where the image corresponds to a first volume segment that is a portion of a longer object, includes reconstructing a first estimate image of a second volume segment larger than the first volume segment. The second volume segment includes the first volume segment. The method also includes applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image. The method further includes re-projecting the hypothetical object image so as to produce a set of simulated hybrid projections corresponding to the first volume segment. The method also includes reconstructing the hybrid projections so as to produce a three-dimensional image corresponding to the first volume segment.
摘要翻译： 一种从由扫描系统生成的一组X射线投影重建三维图像的方法，其中图像对应于作为较长物体的一部分的第一体积分段，包括重建第二估计图像的第二估计图像 音量段大于第一音量段。 第二卷段包括第一卷段。 该方法还包括对第一估计图像应用加权函数以掩蔽第一卷段，以便产生假想对象图像。 该方法还包括重新投影假想对象图像，以产生对应于第一音量段的一组模拟混合投影。 该方法还包括重建混合投影以产生对应于第一体积段的三维图像。
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46.发明授权Apparatus and method for calibrating detectors in a computed tomography scanner 失效用于在计算机断层扫描仪中校准检测器的装置和方法
公开(公告)号：US6148057A
公开(公告)日：2000-11-14
申请号：US184808
申请日：1998-11-02
申请人： Steven N. Urchuk , Carl R. Crawford
发明人： Steven N. Urchuk , Carl R. Crawford
CPC分类号： A61B6/583
摘要： A method and apparatus for calibrating detectors in a computed tomography (CT) system to compensate for differential errors in the detectors are disclosed. Multiple sets of scan data are acquired for a phantom at multiple thicknesses of the phantom. The phantom can be made from multiple slabs of material positioned on the scanner table in a horizontal orientation or in a vertical orientation. Horizontal slabs are removed or added to the stack of slabs to vary the thickness of the phantom. With vertically oriented slabs, each slab is of a different height such that scans of different slabs produce X-ray data for rays having different path lengths and, therefore, attenuations. For each detector, errors in the scan data at the multiple phantom thicknesses are identified and fit to a parametric equation with respect to the log attenuation associated with each thickness. In one embodiment, the parametric equation is a quadratic polynomial. The polynomial is used during subsequent scanning of actual objects to adjust attenuation measurements.
摘要翻译： 公开了一种用于校准计算机断层摄影（CT）系统中的检测器以补偿检测器中的差分误差的方法和装置。 对于体模的多个厚度的体模获取多组扫描数据。 幻影可以由水平方向或垂直方向定位在扫描台上的多块材料制成。 水平板被移除或添加到板的堆叠中以改变体模的厚度。 对于垂直取向的板坯，每个板坯具有不同的高度，使得不同板坯的扫描为具有不同路径长度的光线产生X射线数据，因此产生衰减。 对于每个检测器，在多个幻影厚度处的扫描数据中的误差被识别并且适合于与每个厚度相关联的对数衰减的参数方程。 在一个实施例中，参数方程是二次多项式。 多项式用于后续扫描实际物体以调整衰减测量。
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47.发明授权Apparatus and method for computed tomography scanning using halfscan reconstruction with asymmetric detector system 失效用不对称检测器系统进行半扫描重建的计算机断层扫描仪的设备和方法
公开(公告)号：US5848117A
公开(公告)日：1998-12-08
申请号：US904516
申请日：1997-08-01
IPC分类号： A61B6/03
CPC分类号： A61B6/032 , A61B6/027 , Y10S378/901
摘要： A method and apparatus for halfscan reconstruction in a CT scanning system using an asymmetric detector system are described. In halfscan asymmetric (HSA) reconstruction, a halfscan reconstruction approach is used for data acquired by the symmetric portion of the array, and a fullscan reconstruction approach is used to reconstruct data acquired by the asymmetric portion of the array. When scanning oversized subjects which extend beyond the symmetric field of view of the array, a halfscan reconstruction approach is used which applies a zero weighting to data acquired by the asymmetric portion of the array and ramps data acquired by the asymmetric portion to zero.
摘要翻译： 描述了使用不对称检测器系统的CT扫描系统中半扫描重建的方法和装置。 在半扫描不对称（HSA）重建中，半扫描重建方法用于由阵列的对称部分获取的数据，并且全扫描重建方法用于重建由阵列的不对称部分获取的数据。 当扫描超过阵列的对称视场的超大对象时，使用半扫描重建方法，其对由阵列的不对称部分获取的数据施加零加权，并将由非对称部分获取的数据斜坡化为零。
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公开(公告)号：US5802134A
公开(公告)日：1998-09-01
申请号：US831558
申请日：1997-04-09
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.
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。
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公开(公告)号：US5287276A
公开(公告)日：1994-02-15
申请号：US964335
申请日：1992-10-22
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 projections 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 an warping function which models 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期间从一系列突起中获取投影数据在扫描期间也感测到由呼吸引起的患者胸部的运动，并且获取的运动数据与模拟胸部的扭曲功能一起使用 运动，以计算校正所获取的投影数据并减少通过反投影所获取的投影数据产生的图像中的运动伪影的因子。
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50.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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