共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
本文探讨了CT图像边缘提取的常规方法,引入了启发式搜索算法用于工业CT图像的边缘信息提取;通过这种方法可以得到连接闭合的单象素边缘图像,为将来的序列CT图像三维重建提供了原始数据.最后针对箱包CT图像进行了算法验证,实验表明在图像存在噪声和伪影的情况下,算法仍能检测出满足三维重建需求的边缘信息. 相似文献
3.
4.
5.
人因对系统安全的影响日益突出,但现有的概率安全评估方法对其重视不足.本文建立了一种考虑人因的面向对象贝叶斯网络概率安全评估模型.该模型将人因整合到已有的事件序列图框架中,然后构建面向对象贝叶斯网络模型中的类,并转化为潜在贝叶斯网络进行推理,最后将推理结果整合到事件序列图中进行概率安全评估.利用该模型对核电站失水事故进行了分析,结果表明,该模型不仅适用于实时情境评估的情形,还适用于积累了一定量信息之后的情境评估.由于采用了面向对象的建模思想,有效地降低了建模的复杂程度,非常适用于大型复杂系统安全性建模分析. 相似文献
6.
7.
8.
天幕靶是一种探测弹丸通过空间预定平面时刻的触发传感器,天幕具有一定厚度,并不是一个没有厚度的理想平面,弹丸也并不是一个规则的理想圆柱,所以弹丸穿过天幕不是一个时间点而是一个时刻段.研究弹丸穿过天幕的时间段内哪个时刻点更精确的代表弹丸穿过天幕的时刻点,从而触发计时仪,才能更精确的实现弹丸测速.通过论述弹尖、弹底和幕中触发方式的弹丸过靶信息提取方式,以天幕厚度与测试精度之间的关系为出发点,构建了弹丸穿过光幕的几何计算模型,分析了弹长与幕厚的不同关系下的弹丸过靶信息提取的方法. 相似文献
9.
为实现低成本、高分辨率的小动物单光子发射断层成像(SPECT),设计了一种基于临床探测器和针孔准直器的小动物SPECT成像系统。综合考虑视野尺寸、空间分辨率和绝对探测效率等指标,分别给出了单针孔和七针孔准直器的两种最优化设计方案,并通过对比两种设计方案在全视野范围内的平均空间分辨率和探测效率,对成像性能进行了评估。结果表明,与单孔准直器相比采用七针孔准直器设计可同时获得更高的空间分辨率和探测效率。经蒙特卡罗模拟成像实验验证,该七针孔准直器在临床探测器上可达0.5mm级的超高空间分辨率,且成本远低于采用专用探测器的现有小动物SPECT系统。 相似文献
10.
高精度模拟置输出卡用于控制合肥光源储存环主电源设值,该卡具有较高的精度和较好的稳定度.本文介绍了高精度模拟量输出卡的软、硬件设计,并给出了该卡测试结果. 相似文献
11.
遥感影像尺度转换及最优尺度选择探讨 总被引:2,自引:0,他引:2
从信息提取的角度阐述遥感影像尺度问题的重要性,评述了尺度效应、尺度转换以及最优尺度选择研究的国内、外现状.重点探讨几种不同尺度转换方法,以及基于像元和面向对象的最优尺度选择方法的技术特点,分析了尺度研究未来发展方向. 相似文献
12.
由相叠的低分辨扇形束投影数据重建高分辨CT图像 总被引:5,自引:0,他引:5
在研究扇形束插值代数重建法基础上,提出了由相叠的低分辨扇形束投影数据重建高分辨CT图像的两个新算法,即扇形束的虚拟探测器法和扇形束的直接重建法,并给出和分析了数值模拟结果。 相似文献
13.
14.
15.
《Fusion Engineering and Design》2014,89(9-10):2184-2188
The need of performing high resolution fast neutron spectroscopy in a very harsh environment like that of the Radial Neutron Camera (RNC) of ITER, requires to develop new detectors and methodologies. Diamond detectors have been proved to be excellent candidates but the electronics needs a substantial improvement. Because of the high radiation level and the temperatures expected near the detector positions in the RNC, the electronics must be placed several meters away. A novel Fast Charge Amplifier (FCA) was developed that, connected to a diamond detector using several tens of meters of low capacitance coaxial cable, is able to produce fast output signals suitable to be processed by digital electronics. These fast output signals allow to operate at high count rates avoiding pile-up problems. This novel amplifier connected to a digitizer is here tested in the neutron energy range from 5 to 20.5 MeV using the mono-energetic neutrons produced by the Van de Graaff (VdG) accelerator of the EC-JRC-IRMM and by the PTB cyclotron. From the measurements the experimental response functions of the diamond detector at different neutron energies were obtained. The shape of the response functions have been compared with that predicted with a routine which was implemented for the Monte Carlo code MCNPX with the scope to validate the calculations versus the experimental data. The goal is to develop a tool which allows to calculate the diamond detector response functions also in term of absolute efficiency. This methodology along with the ability to measure at high reaction rates and the insensitivity to radiation damage launches the system described in this paper as a promising method for neutron spectrometry in the RNC of ITER. 相似文献
16.
17.
本文从铀资源勘查后遥感应用技术的研究内容出发,着重从物理意义相关性、反映地质规律深度相关性、时态相关性、平面赋存规律相关性,以及信息相关性的作用机理等5个方面对遥感信息与重力、航磁、航放等地球物理信息之间的相关性进行了初步探讨,为今后从定性和定量角度深入研究后遥感应用技术中遥感信息与其他地学信息之间的相关性开创了一个良好的开端。 相似文献
18.
卫星遥感及其应用的发展态势 总被引:4,自引:0,他引:4
简述了卫星遥感传感器分辨率、辐射精度、卫星运行模式、载荷形式、数据处理,以及遥感应用等方面的最新进展,卫星遥感传感器分辨率显著提高,多传感器的有效集成是21世纪卫星遥感的新概念和新技术。后遥感应用技术是遥感技术深化应用的重要组成部分,具有重要的实践意义。 相似文献
19.
U. Gelius L. Asplund E. Basilier S. Hedman K. Helenelund K. Siegbahn 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1984,1(1):85-117
The design and performance of a new high resolution multipurpose instrument are described and illustrated. The instrument comprises a high-power, fine-focusing e?-gun, a high speed rotating anode, a double focusing multi-crystal X-ray monochromator, a monochromatic UV-source with a toroidal grating, a fine-focus variable energy e?-source, a four-element electrostatic e?-lens system, a large 36 cm hemispherical electrostatic analyzer, a 12 cm wide electron multi-detector system and a dedicated computer system. Various sample probes for gases, liquids and solids are discussed. The instrument is shown to reach an energy resolution of at least 0.23 eV with X-ray excitation at a sufficient intensity to enable the study of gases.A number of illustrative examples of the proved instrumental performance is presented. A new “line-sharpening” effect, due to post-collision interaction in Auger electron spectra, is revealed due to the high spectrometer resolution. The strongest vibrational components of the C 1s ESCA line from methane are for the first time resolved. High resolution spectra are also presented for solids, e.g. the spin-orbit split Si 2p line is well resolved into two components and new resolved structures appear in the Ag and Au valence bands. Calculated density of states are found to be in good agreement with these structure rich d-bands. Phonon excitation accompanying the photoionization process is discussed in relation to its causing additional broadening of the Si 2p lines. 相似文献
20.
An improved acoustic-holographic reconstruction-algorithm is presented which allows a three-dimensional image-reconstruction, together with - for the first time - an axial resolution much below one wavelength. This high resolution makes it possible not only to evaluate exactly the contours of defects in the axial direction but also to measure its deformation under thermal or mechanical load. Experimental measurements correspond to the theoretical model, being limited primarily by the dynamic range of the experimental setup. 相似文献