用于工业CT图像三维重建的边缘信息提取算法研究

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.     

大型集装箱检测系统中图像的去噪增强算法

提出了基于图像边缘信息的去噪增强算法，能有效区分错误噪声行，随机噪声和有用边缘，分别进行不同的图像处理，能在抑制噪声的同时增强图像边缘，提高大型集装箱检测系统的图像质量。     

基于自适应NLM修正的CT重建算法

针对稀疏角度CT图像重建问题,J.Huang等人提出了ART-NLM算法。该算法利用NLM对每次ART重建后的图像进行滤波去噪。虽然噪声抑制得到明显改善,但图像结构边缘模糊。论文在ART-NLM基础上改进NLM,通过自适应选取滤波参数及相似块的旋转变换,对待重建图像进行自适应NLM滤波,以达到同时去除噪声和保护边缘的目的。Shepp-Logan体模仿真实验表明,与传统ART-NLM算法相比,新算法提高了重建图像质量,有效平衡了图像去噪和边缘保护。     

基于视频识别和激光雷达的实物保护探测装置

<正>本研究实现了一套基于深度学习算法和激光雷达技术的主动式人员活动探测预警系统。该系统主要包括视频分析检测模块、激光雷达点云数据聚类分析模块以及系统控制模块。视频分析检测模块采用深度学习算法依靠GPU运算完成视频流中目标图像的识别。深度学习算法是通过低层信号到高层特征的函数映射,来建立学习数据内部隐含关系的逻辑层次模型,以模仿人脑的认     

人机交互低能辐射探测系统设计

设计了一种基于CMOS图像传感器与FPGA结合HMI(HumanMachineInterface)的低能辐射探测系统。该系统通过HMI将数据传输至手机APP,使用手机APP对探测结果进行显示并同步HMI进行远程控制。优化前端算法,提出了BP神经网络与边缘检测求和算法相结合的算法。利用60Co对系统的精确度与灵敏度进行测试,实验结果表明,通过BP神经网络与边缘检测求和算法的结合,采用HMI进行无线远程控制,可实现低能辐射在线探测技术的高精确度和高灵敏度特性。     

大型集装箱CT系统图像重建研究

研究了大型集装箱CT系统的图像重建技术,给出了卷积反投影算法的基本原理、实现过程,以及目前得到的重建图像。经实际检验,应用该算法重建的图像清晰,能够识别铸造工件中的孔及树木的年轮。     

射线图像的快速纹理提取算法

局部二值模式(LBP)可提取模糊的射线图像纹理,但无法描述像素间灰度差异程度,不能有效区分冗余的微小灰度变化。针对上述问题,本文提出了一新型的快速纹理提取算法C-LBP。新算法首先引入复冲击滤波器对图像进行预处理,提取图像虚部数据作为下一步纹理提取的输入。然后嵌入相对光滑的比较函数来改进LBP,并考虑圆域内中心点和邻点的灰度相似距离,区别对待圆域内的灰度信息。最后,增加一计数策略,以淘汰冗余的微小灰度变化。实验证实C-LBP具有处理时间短和检测效果好双重优势,保留了对较大灰度的敏感性,增强了对灰度差异程度的描述能力,可有效增强图像、提取边缘和识别缺陷。     

一种基于阈值分割的CT图像环状伪影消除方法

空域内的极坐标变换法及其衍生算法是一种常用的环形伪影消除方法。虽然极坐标法效果好,处理速度快,但是缺点同样明显:处理后的图像会出现明显的模糊,尤其是图像的边缘地带。论文提出的自适应分割算法在极坐标方法的基础上进行了改进,经实验证明,该算法在保证伪影消除效果的同时,最大限度地避免了图像边缘的模糊。同时,算法还会自动跳过无需处理的区域来减小计算量,从而加快图像处理速度。     

基于反锐化掩模的辐射图像信息增强算法

大型集装箱检查系统获得的辐射图像对比度都较差,影响视觉效果。因此对其对比度增强处理是非常必要和有意义的。在参考和总结大量对比度增强算法的基础上,提出了将反锐化掩模、自适应非线性滤波以及数学形态学等数字图像处理方法结合起来用于增强辐射图像信息的新算法。在增强辐射图像对比度的同时,尽可能保持了原始图像的边缘细节信息。算法在实际的辐射图像处理中获得了较好的效果。     

推扫型背散射成像系统图像质量优化

推扫型背散射成像技术是一种成像布局灵活、对有机物敏感的新型成像技术。在以较高速度进行成像的情况下,其探测效率和图像对比度受到一定限制。本文基于自主研发的推扫型背散射成像系统,设计开发了一套专用图像处理算法,包括归一化校正、衰减校正,图像去噪,图像增强,图像分割等,以降低图像噪声和提高图像对比度。目前此算法已实际应用于成像系统进行实验验证,图像质量具有明显改善,是一种行之有效的算法。     

Improved plasma position detection method in EAST Tokamak using fast CCD camera

To control the steady-state operation of Tokamak plasma, it is crucial to accurately obtain its shape and position. This paper presents a method for use in rapidly detecting plasma configuration during discharge of the Experimental Advanced Superconducting Tokamak device. First, a visible/infrared integrated endoscopy diagnostic system with a large field of view is introduced,and the PCO.edge5.5 camera in this system is used to acquire a plasma discharge image. Based on the analysis of various traditional edge detection algorithms, an improved wavelet edge detection algorithm is then introduced to identify the edge of the plasma. In this method, the local maximum of the modulus of wavelet transform is searched along four gradient directions, and the adaptive threshold is adopted. Finally, the detected boundary is fitted using the least square iterative method to accurately obtain the position of the plasma. Experimental results obtained using the EAST device show that the method presented in this paper can realize expected goals and produce ideal effects;this method thus has significant potential for application in further feedback control of plasma.     

Blowdown force analysis of piping system under LOCA conditions using BLOWDOWN code

The BLOWDOWN code was developed for blowdown force analysis of piping system under LOCA conditions. This is a post-processor of the thermal-hydraulic analysis code RELAP4/MOD6. The results obtained from the RELAP4/MOD6 code are converted into blowdown forces by the BLOWDOWN code.In the paper, the physics and algorithms of the BLOWDOWN code are outlined. Some numerical examples are also presented to show the effectiveness of the code.     

比值法下基于不同选择策略的遗传算法换料优化比较分析

遗传算法是一种应用于反应堆换料优化问题的经典算法,该算法的一个重要组成部分为选择策略。在目前的文献中,选择策略常直接选轮盘赌选择法或随机竞争选择法,缺乏对不同选择策略的比较与分析。为得到寻优能力最强的选择策略,本研究以钍基柱状高温气冷堆1/6堆芯为例,以比值法构造适应度函数,利用DRAGON程序进行堆芯物理计算,结合精英保留策略,对轮盘赌选择法、随机竞争选择法、均匀排序法、指数排序法和确定式选择法5种选择策略的寻优能力进行了比较分析。分析结果表明,在这5种选择策略中,指数排序法的寻优能力最强,是最适合求解换料优化问题的选择策略。      

Computerised defect sizing using ALOK analysis in shrunk-on wheel of turbine rotor

A computerised defect evaluation system using an advanced ultrasonic technique for shrunk-on wheels of a turbine rotor has been developed. The flaw image was reconstructed by a modified ALOK method with attention to the tip diffraction echoes of stress corrosion cracking (SCC). The results of the application of this system to the mock-up wheel with artificial slits and real SCC cracks show that this system is very useful for crack sizing and locating.     

基于硬件实现的锥束CT图像重建系统的存储机制设计

为了实现三维锥束CT图像重建加速系统的小型化,建立了基于FPGA的三维图像重建系统。并对该系统中所采用的FDK重建算法所需的数据存储量和数据传输量以及由SDRAM、SRAM和FPGA内部缓存组成的存储系统的数据吞吐率进行了研究。首先,根据FDK算法的滤波与反投影两个步骤介绍了三维锥束CT图像重建系统的数据规模。接着,介绍了一种以SDRAM为外部主存,以SRAM为外部缓存和以FPGA内部SRAM资源作为内部高速缓存的存储机制。然后,介绍了该存储机制的实现方法以及测试方法。最后对该三维图像重建系统的数据吞吐能力进行了测试,并将之与FDK算法所需的数据传输量进行了对比分析。试验结果表明:该存储机制的数据连续存取速度为151.9MB/s,数据随机存取速度为100MB/s,基本满足小规模的三维图像重建的数据存储与传输带宽的要求。     

密集粒子径迹的粘连分离

粒子径迹测量技术的核心问题为粘连径迹的分离。本文针对超密粒子径迹显微图像的粒子密度高、径迹粘连严重、颗粒度差异大、径迹内部灰度不均匀且存在杂质等特征,分析现有粘连分离算法存在的问题,提出了一种密集粒子径迹粘连分离方法。先对径迹显微图像进行增强,再进行扩展极大值分割,采用数学形态学及面积比例法分离图像内部粘连径迹,并对边缘处的径迹及无孔洞的单个径迹进行特殊处理。实验结果表明,算法能有效处理径迹显微图像,快速精确定位径迹轮廓,实现密集粒子径迹的粘连分离。     

移动式大型集装箱检测系统图像的矫正与放大研究

介绍了移动式大型集装箱检测系统图像的几何矫正的算法，给出了矫正前后图像的比较分析，并讨论了图像放大的算法。由于这些算法的采用，图像质量得以提高。     

FuzzyFTA: a fuzzy fault tree system for uncertainty analysis

This paper describes a new approach and new computational system, FuzzyFTA, for reliability analysis using fault tree and fuzzy logic. Some measures are defined to determine critical components and the uncertainty contribution of each one to the system. The FuzzyFTA system includes algorithms to consider the minimal cut set approach for the top event calculation. After that, these algorithms are used to determine importance measures. The computer code application is the Auxiliary Feedwater System (AFWS) analysis, a recent study made for Angra-I, Brazilian NPP.     

Alfvén eigenmode stability analysis and energetic particle transport prediction for CFETR hybrid scenario

The hybrid scenario is a projection for CFETR operation with high plasma current and density. Therefore, the energetic particles (EPs) generated by fusion reactions can destabilize Alfvén eigenmodes (AEs), which could result in significant EPs loss and redistribution. Both the eigenvalue code NOVA-K and the wrapped local stability code TGLFEP are used to analyze AE stability. The simulation indicates the beta-induced Alfvén eigenmodes with n>5 in the core region are the most unstable. The NOVA-K code is used to benchmark the critical density gradient calculated by TGLFEP. In addition, the EPtran code is employed to predict EP transport induced by unstable AEs and turbulence, which reduce EP density in the core and drive approximately 30% EP transport from the core to the edge, thus the EP density profile flattens and EPs with lower energy deposit near the edge.     

Temporal adaptive algorithm for TRAC-BF1/NEM/COBRA-TF coupled calculations in BWR safety analysis

A temporal adaptive algorithm was developed to perform the synchronization and optimization of the performance of TRAC-BF1/NEM/COBRA-TF three-dimensional neutron/thermal-hydraulics sub-channel analysis coupled code system. The multi-level coupling scheme for time synchronization of the TRAC-BF1/NEM and COBRA-TF under PVM is developed considering the different time-step selection algorithms of TRAC-BF1, NEM and COBRA-TF codes. The developed methodology allows one to synchronize the codes in time without doing significant code modifications to the time-step selection logic of the involved codes. The advantage of this approach is that COBRA-TF can capture the nature of a given transient, without losing any time-dependent data. Results for steady state and transient calculations that show how the implemented temporal adaptive algorithm works are presented. In addition selected results are presented to illustrate dynamic behavior and the type of thermal-hydraulic boundary conditions provided by the system code.