基于PLC的X射线无损检测系统研究CSCD

研制基于PLC的X射线无损检测系统,系统主要应用于木材内部结构成像,呈现出横切面、径切面和弦切面木材内部图像。设计搭建西门子S7-1200PLC控制系统、升降旋转检测平台、CT检测设备,编写下位机控制程序和上位机人机交互界面。调试设备,将木材试样放于升降旋转检测平台中心,开启升降旋转检测平台和CT检测设备。在对木材试样进行扫描的过程中,X射线源发射扇形束X射线,X射线穿透木材试样。由X射线探测器接收数据,上传至上位机进行数据处理,完成图像重建。本研究完成了无损检测系统平台的设计调试,精确控制升降旋转检测平台动作,旋转精度达0.01°/s,升降精度达0.01mm/s。精确、稳定的运动控制使采集的投影数据准确可靠,实现了木材内部的高质量横经弦三切面成像。设计双伺服电机同步控制系统,实现基于PLC的X射线无损检测平台高精度控制,旋转和升降精度均达到较高水平,同步性能优越,完全满足科研人员对木材扫描要求,重建出高质量、高分辨率的木材内部构造图像,为木材无损检测提供了新方法。     

基于PLC的X射线无损检测系统研究

研制基于PLC的X射线无损检测系统,系统主要应用于木材内部结构成像,呈现出横切面、径切面和弦切面木材内部图像。设计搭建西门子S7-1200PLC控制系统、升降旋转检测平台、CT检测设备,编写下位机控制程序和上位机人机交互界面。调试设备,将木材试样放于升降旋转检测平台中心,开启升降旋转检测平台和CT检测设备。在对木材试样进行扫描的过程中,X射线源发射扇形束X射线,X射线穿透木材试样。由X射线探测器接收数据,上传至上位机进行数据处理,完成图像重建。本研究完成了无损检测系统平台的设计调试,精确控制升降旋转检测平台动作,旋转精度达0.01°/s,升降精度达0.01mm/s。精确、稳定的运动控制使采集的投影数据准确可靠,实现了木材内部的高质量横经弦三切面成像。设计双伺服电机同步控制系统,实现基于PLC的X射线无损检测平台高精度控制,旋转和升降精度均达到较高水平,同步性能优越,完全满足科研人员对木材扫描要求,重建出高质量、高分辨率的木材内部构造图像,为木材无损检测提供了新方法。     

微机控制DR／ICT射线检测系统的研制

工业X射线检测是通过数字射线成像（DR）和工业计算机层析（ICT）对金属构件进行无损检测的一项技术,结合一套DR／ICT检测设备的研制,把微机控制应用到检测系统伺服驱动和图像采集模块的控制中,实现了工业射线自动检测和控制功能,并通过实验验证了系统的可靠性和稳定性。     

基于3线阵探测器的亚像元成像超分辨率重构

虽然增加探测器的时间和空间采样频率可以提高亚像元成像系统空间分辨率,但探测器采集到的数据易发生混叠,使重构得到的图像的分辨率无法达到理想值。本文以3片线阵探测器亚像元成像为基础,提出一种超分辨率重构算法。首先,在高分辨率网格上建立插值模型;然后,辨识插值重构图像在线阵列方向和扫描方向的模糊核,得到整幅图像的模糊核;最后,采用带有Neumman边界条件的梯度平滑正则化模型去除模糊,抑制振铃效应。实验结果表明,该算法使亚像元成像系统分辨率为单线阵探测器无过采样成像系统分辨率的2.6倍;与双线性插值法相比,平均灰度等级(GMG)提高了7.71。该算法可以进一步实现对更多片线阵探测器亚像元成像的超分辨率重构,获取更高的系统分辨率。     

双层平板探测的双能成像检测系统

本文提出一种使用双层平板探测器单次曝光获取X射线双能图像,并实现双能减影的成像检测方法.介绍了单层平板、双层平板探测器结构以及双层平板探测成像系统工作原理.仿真分析不同、相同管电压在不同滤过下X射线的能谱变化,进一步通过试验分别探究使用kVp切换,双层平板方案时胸部体模双能成像特性.研究发现kVp切换、双层平板方案采集...     

X射线数字成像检测技术在GIS设备上的应用

为将GIS设备故障消除在缺陷发展初期,必须要有一种"可视化"的无损检测手段帮助寻找缺陷,X射线检测技术正是苦苦寻求的良药。采用X射线数字成像检测技术,对GIS设备内部结构进行透射,并在成像板上得到设备内部结构影像,通过图像处理系统的分析处理,在GIS设备不解体的情况下得到了清晰的内部结构影像,实现了"可视化"无损检测的目的,为GIS设备的故障诊断及检修提供了技术支持。     

微型X射线数字成像系统研究

X射线数字成像检测与诊断技术是X射线检测的发展趋势,微型X射线数字成像系统采用X射线敏感CCD面阵探测器作为射线探测元件,具有体积小、分辨率高、实时性好的特点。本文研制了基于X射线敏感CCD的微型X射线数字成像系统,介绍了整个系统的组成,阐述了X射线敏感CCD的工作原理,选定了系统采用的X射线敏感CCD,设计了CCD探测器的驱动电路、模数转化电路、数据采集与通讯电路、图像获取及处理软件等。该系统采用USB2.0接口与计算机进行通讯,直接采用USB接口电源供电,无需外部电源,结构简单。分辨率测试表明,该系统的分辨率>10lp/mm。     

基于CMOS视频采集卡的X光管道环焊缝检测系统

研发了一种针对CMOS图像传感器的高效视频采集卡,并运用于X射线管道环焊缝无损实时检测系统。首先选用合适的CMOS图像传感器和闪烁材料设计出了X光相机面板,完成了X光到可见光再到模拟电信号的转换;再根据传感器特性设计了基于ARM与CPLD的视频采集卡,实现了面板采集模拟电信号的数字转换;数据用TCP/IP协议传送到远端PC机,可保证野外作业无铅房防护工作人员的人身安全。PC终端的图像处理模块根据采集卡数据实时成像,成像效果可达B级无损探伤胶片标准。视频采集卡同时控制环形轨道爬行机构的周向运动,拍摄与爬行相互协调,实现了对管道环焊缝的灵活检测。该系统适合恶劣工况,性能稳定、操作简便,具有广阔的应用前景。     

基于神经网络算法的故障检测技术

针对复杂的机电产品内部构件状态检测这一工程难题,本文介绍了一种自动在线检测系统.该系统采用X射线对产品成像,运用数字图像处理技术对射线图像进行预处理,由神经网络算法进行故障诊断.故障识别模型采用了改进的BP神经网络算法,以正常装配状态时的多幅图像经预处理后作为学习样本训练BP神经网络.检测时一般只需拍摄两幅不同方位的图像,经预处理后输入神经网络与样本图像进行比较判断,即可识别出关键元器件的状态.该系统将数字射线成像技术和图像处理技术相结合,并在故障识别算法中采用了神经网络算法,提高了产品故障的检测速度和可靠性,在工业无损检测领域具有一定的实用性.     

大面阵高帧频CMOS成像电子学系统设计

为了满足大面阵高帧频CMOS探测器成像系统的设计要求,设计了基于GMAX0504探测器的CMOS成像系统,实现高帧频、大视场的成像需求;采用DDR3-SDRAM和NAND-FLASH,解决了图像数据存储速率与容量的瓶颈问题;通过图像处理的方法,提高了图像动态范围、信噪比(SNR)与调制传递函数(MTF)的设计指标;通过图像实时像元校正,提高了成像系统的光响应非均匀性(PRNU)指标。实验结果表明,图像信噪比(SNR)平均值为44dB,接近探测器的最大信噪比(SNR);光响应非均匀性(PRNU)均值为1.4%,满足成像需求。该CMOS成像系统设计结构可应用于更大面阵CMOS成像系统,为工程应用提供了保障。     

X光机数字化的研究进展

数字化X光机相对于传统屏片式X光机具有的高灵敏度,低噪声,数字化图片等优点。详细介绍两种X光机数字化方法:计算机X射线摄影(CR)和数字X射线摄影系统(DR)的组成部分、工作原理和最新进展。最后给出了各种X光机量子探测率和MTF随空间分辨力变化曲线,说明基于直接型平板探测器的DR系统具有更优越的性能,是数字化X光机的最终发展方向。     

Optimization the parameters of multichannel continuously scanning digital X-ray radiography systems

Analytical formulas for optimal selection of the values of the main parameters of a multichannel continuously scanning digital X-ray radiography system, which is based on a linear detector array, and the minimum required value of the exposure dose rate from an X-ray source are obtained using the specified values of the system’s spatial resolution in the “worst case” and the testing capacity taking the digital filtering of the radiation detection results into account.     

Low cost digital radiography system for weld joints and castings testing

A low cost digital radiography system (DRS) for testing weld joints and castings in laboratory was assembled. The DRS is composed from X-ray source, scintillator, first surface mirror with Aluminum coating, charged coupled device (CCD) camera and lens. The DRS was used to test flawed carbon steel welded plates with thicknesses up to 12 mm. The comparison between the digital radio-graphs of the plates weldments and the radiographs of the same plates weldments using medium speed film type had shown that, the detection capability of the weld flaws are nearly identical for the two radiography techniques, while the sensitivity achieved in digital radiography of the plates weldments was one Image Qualits Indicator (IQI) wire less than the sensitivity achieved by conventional radiography of the same plates weldments according to EN 462-1. Further, the DRS was also successfully used to test (100 × 100 × 100) mm³ Aluminum casting with artificial flaws of varied dimensions and orientations. The resulted digital radiographs of the casting show that, all the flaws had been detected and their dimensions can be measured accurately, this confirm that. The proposed DRS can be used to detect and measure the flaws in the Aluminum and others light metals castings accurately.     

Calculation of the velocity vector field of metal foaming in radiographic sequences

X-ray radiography is extended by a digital image processing method for measuring the velocity vector field of metal foaming in radiographic sequences. A tensor approach coupled with interpolation using an adaptive Gaussian window is proposed. The method was successfully tested on experimental images.     

Consideration of digital filtering during selection of parameters of multichannel continuously scanning digital X-ray radiography systems

The problem of optimal selection of the aperture length of an individual detector in a linear array, the radiation detection time, and the pulsed response of a digital filter has been solved in two versions for continuously scanning digital X-ray radiography systems containing a linear detector array. The maximum spatial resolution of the system in the scanning direction at a specified testing capacity served as the criterion for the optimal selection.     

Investigation of laser-welded titanium and stainless steel specimens using digital radiography methods

Specimens of ??titanium-titanium?? and ??titanium-12X18H10T steel?? welded joints that were obtained using laser radiation were investigated. When ??titanium-12X18H10T steel?? welded joints were formed, a copper plate was used as the intermediate insert. The digital computer radiography method using phosphorous image plates was used to study specimens; images were read out from image plates using an HD-CR 35 laser reader produced by Durr NDT. Fuji SR and Kodak SO-170 image plates were used in the experiments. The relative contrast sensitivity of X-ray images of specimens that was obtained experimentally was 1?C1.5% at exposures that were two to three times lower than for conventional radiography on an X-ray film. Defects with openings of > 0.1 mm were detected.     

高质量X射线检测数字化成像及图像采集

X射线数字成像检测是工业无损检测的新技术.非胶片实时数字成像检测以其高效率、低成本,特别是数字图像的可交换性和存储方便等特点成为射线检测的发展趋势.通常使用的由射线像增强器、视频摄像机、图像采集卡和计算机组成的系统成像质量差且只能在低能X射线下使用,作者经过反复研究和实验,研制了基于单晶闪烁屏和科学级CCD相机的可用于高、低能X射线高分辨率、高对比灵敏度数字成像检测系统.介绍了整个检测系统的组成,设计了科学级制冷CCD相机、预处理电路、A/D转换电路、微机EPP方式快速数据采集电路和软件等.给出了某铝铸件(厚150mm)在加速器高能X射线下的成像结果.实验证明该系统比普通像增强器和视频相机组成的系统具有适应射线能量范围宽和成像质量好的优点(成像时间长一些).系统的空间分辨率大于3lp/mm, 检测物体50mm(等效钢厚)以上时,对比度灵敏度小于1%.     

Radiopacity of tantalum-loaded acrylic bone cement

Radiopacifying agents are commonly added to bone cements to enhance the visibility of the cement in radiography. The radiopacifiers usually employed may, however, have undesired effects on the mechanical properties of the cement. A potentially new radiopacifier is tantalum, which in the present work was evaluated in terms of radiopacity. Bone cements containing different percentages of tantalum were compared with plain bone cement as well as with formulations containing different percentages of the commonly used radiopacifier barium sulphate. The radiopacity was assessed quantitatively and qualitatively, by measuring with a digital densitometer the optical density of the cement on X-ray films, and consulting the expertise of ten orthopaedic surgeons. It was found that tantalum does present radiopacity, but not as high as barium sulphate under the specific conditions applied to this study.     

Effect of Radiant Energy on the Formation of Optical Image in X-Ray Inspections

Digital radiography is currently a genuine alternative to the laborious and uneconomical method of X-ray diffraction in nondestructive testing. The processes of forming optical images on a radiographic film and on a flat-panel detector are different. The input action on a detector, whether a radiographic film or a digital transducer, is the so-called radiation image, the X-ray radiation generated by an X-ray tube and transmitted through a test object. The object attenuates radiation depending on its own thickness and material density. The main parameters of the radiation image are its contrast, definition, and signal-to-noise ratio (SNR). In order to achieve the most efficient conversion of the X-ray image into an optical one, one needs to choose the optimum combination of the listed parameters depending on which detector is being used. In this study, theoretical research and practical evaluation of its results have been carried out. Conditions have been determined for the best adaptation of a radiation image to the employed detector that ensure the prescribed quality indicators of the optical image of the test object. Results of the research that was carried out within the framework of scientific field 2.3 “Developing methods for automated nondestructive testing and the reliability of its results” (“Strategic directions of development of materials and technologies of their processing for a period of up to 2030”) are provided.     

CR系统的现状及进展

随着医学生物工程、光电子学以及计算机科学的进步,X射线机取得了长足的发展。重点介绍了计算机X射线摄影系统(CR)的组成部分、工作原理和最新进展。该系统可安装于传统X光机中,实现传统屏片式X光机的数字化。具有便于携带、灵活性高等优点,为保障人类健康发挥着重要的作用。