共查询到19条相似文献,搜索用时 296 毫秒
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周嘉维 《中国原子能科学研究院年报》2002,(1):115-115
这是一个涉及多学科相关技术的项目,计算机数字成像是该项目中的一部分,即将前端设备送来的信号作相应处理,然后以数字成像的方法在计算机屏幕上显示出来。已实现的功能包括:实时控制系统的启动、停止,实时数据获取,探测器零点校正,探测器效率校正,实时成像,图像缩放, 相似文献
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本文探讨了在测定辐射成像系统的检测灵敏度时,用计算机代替人眼对检测图像进行判别的原理,方法以及实际应用时存在的一些问题,确定并实现了一套初步可行的算法。 相似文献
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核磁共振成像,是继X射线CT、单光子发射CT(SPECT)和正电子发射CT(PET)等计算机断层成像方法之后,在80年代崛起的最先进的成像技术。它初露崭头就已具备了许多优势,正日趋广泛地用于临床诊断和生理、病理研究,其前景相当喜人。这个全新的成像原理是首先由美国纽约洲立大学的P.C.Lauterbur教授在1973年提出 相似文献
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借助计算机模拟成像,通过分析不同情况下的图像重构,研究了抽样间距和投影数、重构算法、荧光测量等若干因素对图像重构质量的影响,并得出了一些有益的结果,对实际应用具有一定的参考意义。 相似文献
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分析了已有的各种核辐射剂量场测量方法的基础上, 利用闪烁体吸收发光特点并结合计算机实时成像处理技术,提出了对剂量场分布进行实时成像测量的新方法——阵列式吸收发光CT 法。研制出闪烁光纤阵列构成的探测器及其伺服控制系统, 用高灵敏度的电荷耦合器件(CCD)拾取探测器产生的微弱闪烁光信号,并采用定点采集的方法对视频信号进行数据的快速采集。在图像重建方法上, 提出了迭代滤波反投影重建方法和利用非完全投影进行数据修复,对获取的投影数据进行变换和处理,并通过选择滤波函数及其适当的参数, 可获得最佳滤波效果,以重建剂量场的二维场分布,从而建立了剂量场的实时、高精度的成像测量系统。 相似文献
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高分辨micro-SPECT成像系统针孔准直器的优化设计 总被引:2,自引:2,他引:0
为了最大限度地减少γ射线在针孔准直器上的透射和散射效应,采用蒙特卡罗方法对单光子发射计算机断层(SPECT)成像系统使用的针孔准直器进行优化.模拟计算结果与实验测试得到的系统灵敏度和空间分辨率曲线相符,达到了高分辨小动物成像的要求. 相似文献
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CT自从被发明以来其技术已发生了很大的变化.这些变化不仅体现在计算机技术、探测器技术和X线技术方面,同时CT的图像重建算法也在不断地发展.本文提出的中间函数重建算法,是一种可以应用于扇束和锥束扫描的图像重建算法.研究它的目的是为将来的锥束扫描提供直接重建算法. 相似文献
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平衡法放射性核素心血管造影局部室壁运动的定性分析有助于对室壁运动异常作出评价。但由于评价结果主要由观察者依据心室舒张末期及收缩末期这二个时相的边界叠加影象来判断,因而主观因素不可避免。特别是对冠心病例,其室壁运动“正常”与“运动低下”之间的鉴别尤为困难,对室间隔的活动也往往难于估价。为此,本文研究了局部室壁运动的计算 平衡法放射性核素心血管造影局部室壁运动的定性分析有助于对室壁运动异常作出评价。但由于评价结果主要由观察者依据心室舒张末期及收缩末期这二个时相的边界叠加影象来判断,因而主观因素不可避免。特别是对冠心病例,其室壁运动“正常”与“运动低下”之间的鉴别尤为困难,对室间隔的活动也往往难于估价。为此,本文研究了局部室壁运动的计算 相似文献
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Computers are needed in nuclear medicine, they answer a need to avoid loss of patient data and are necessary for image processing which deserves a wider use than it presently enjoys. The computer is nearly essential for dynamic or function studies and its use is due to increase. If a computer is to function effectively in clinical service, the processes it executes must be finished in a very short time. This time constraint means that clinical programs must be assembly language programs rather than slower "higher level" language programs. A computer is near its speed limit while servicing a gamma camera and while processing images. Full use of the computer for nuclear medicine requi'res development of systems providing rapid and reliable image processing and production of hard copy results, of course, at a reasonable cost. 相似文献
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The techniques of digital image analysis and enhancement have been applied to TEM micrographs. Digitized micrographs of irradiated A1 and Mo containing cavities were enhanced by applying digital unsharp masking and thresholding techniques. These techniques produce enhanced images that allow for more effective analysis of image features using conventional analysis methods as well as computer methods. For the Mo data, a template-matching algorithm was applied to thresholded data and a computer-generated void histogram was obtained. The computer analysis gives results that are in agreement with conventional analysis of the same data. It is concluded that computer methods for cavity/void analysis can be successfully developed. 相似文献
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Chapuy S. Dimcovski M. Dimcovski Z. Lehmann E.H. Pachoud M. Valley J.-F. Verdun F.R. Vontobel P. 《IEEE transactions on nuclear science》2001,48(6):2357-2364
We present in this paper industrial nondestructive X-ray and neutron testing applications with a real-time digital imaging device and control system X-View based on active matrix flat-panel imager technology. X-View consists of X-ray or neutron converters, arrays of amorphous silicon (a-Si:H) thin-film transistors and photodiodes, a fast real-time electronic system for readout and digitization of images and appropriate computer tools for control, real-time image treatment data representation, and off-line analysis. Some basic image-quality parameters and different objects were assessed for quantitative and qualitative analysis. Results show a wide dynamic range (16 bits ADC resolution) and lack of blooming, a high frame rate (up to 25 fps), and rapid image capture. Images are directly displayed, on-line, on a PC monitor and archived in a digital form for radiography and radioscopy procedures and limitless industrial applications in X-ray and neutron inspections 相似文献
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For discontinuity analysis more and more sophisticated methods are used in the nuclear industry. The rapid development of computer technology offers the possibility to use imaging techniques. Instead of specialized focusing transducers the more flexible synthetic focusing techniques can be used. Presupposing that the material is ultrasonically isotropic and homogeneous, imaging techniques make it possible to visualize the reflectivity of the volume to be tested.Siemens developed the high speed holographic instrument Holo 3000 in cooperation with the University of Bochum. In this paper the method of Broad Band Holography is presented in the context of other imaging techniques.Different filtering methods have been investigated in order to achieve highest resolution and best signal to noise ratio with a given dataset. Different transducers respective wave modes have been applied to austenitic welds and claddings. The reconstructed image was evaluated using image processing techniques in order to investigate the possibilities to produce results easier to be quantifed than the original reconstruction.The results presented show a reliable expert tool for analysis measurements which also can be used for flaw detection. 相似文献