Centimeter-sized Cs_(3)Cu_(2)I_(5)single crystals grown by oleic acid assisted inverse temperature crystallization strategy and their films for high-quality X-ray imaging

Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.

Performance of Large Area Thin-Film CdTe Detector in Diagnostic X-Ray Imaging

Significant advancement in thin-film cadmium telluride (CdTe) deposition techniques in recent years has made this material attractive for the development of low-cost large area detector. Here we evaluate the intrinsic performance of the detector for a range of energies relevant to diagnostic imaging applications, such as fluoroscopy. The input x-ray spectra for a set of tube potentials ranging from 70 to 140 kVp were computed with the tungsten anode spectral model using interpolating polynomials (TASMIP) based on the measured output of our diagnostic x-ray simulator. Frequency-dependent detector performance analysis was conducted through Monte Carlo simulations of energy deposition within the detector. Intrinsic modulation transfer functions (MTF), noise power spectra (NPS), and detective quantum efficiencies (DQE) were computed for a set of CdTe detectors of varying thickness, from 100 to 1000 μm. MTF behavior at higher frequencies was affected by thickness and input energy, NPS increased with film thickness and energy, and the resultant DQE(f) decreased with increasing the input energy, but increased with the thickness of the detector. We found that the optimal thickness of CdTe under diagnostic x-ray beam is in the range of 300 to 600 μm. Physical properties of CdTe, such as the high atomic number and density, used in direct detection configuration, together with the recently established thin-film manufacturing techniques makes this technology a promising photoconductor for large area diagnostic flat panel imaging.

Application of molybdenum target X-ray photography in imaging analysis of caudal intervertebral disc degeneration in rats

BACKGROUND Conventional plain X-ray images of rats,the most common animals used as degeneration models,exhibit unclear vertebral structure and blurry intervertebral disc spaces due to their small size,slender vertebral bodies.AIM To apply molybdenum target X-ray photography in the evaluation of caudal intervertebral disc(IVD)degeneration in rat models.METHODS Two types of rat caudal IVD degeneration models(needle-punctured model and endplate-destructed model)were established,and their effectiveness was verified using nuclear magnetic resonance imaging.Molybdenum target inspection and routine plain X-ray were then performed on these models.Additionally,four observers were assigned to measure the intervertebral height of degenerated segments on molybdenum target plain X-ray images and routine plain X-ray images,respectively.The degeneration was evaluated and statistical analysis was subsequently conducted.RESULTS Nine rats in the needle-punctured model and 10 rats in the endplate-destructed model were effective.Compared with routine plain X-ray images,molybdenum target plain X-ray images showed higher clarity,stronger contrast,as well as clearer and more accurate structural development.The McNemar test confirmed that the difference was statistically significant(P=0.031).In the two models,the reliability of the intervertebral height measured by the four observers on routine plain X-ray images was poor(ICC<0.4),while the data obtained from the molybdenum target plain X-ray images were more reliable.CONCLUSIONMolybdenum target inspection can obtain clearer images and display fine calcification in the imaging evaluation of caudal IVD degeneration in rats,thus ensuring a more accurate evaluation of degeneration.

Rapid digitalization and panoramic evaluation of weld X-ray film

The computer evaluation of weld X-ray film is an attractive technique for weld seam NDT （ nondestructive testing）. To achieve this target, digitalization of film is the first step and automatic defect identification is another key technique. In this paper, a weld X-ray film digitalizing system has been established with linear array CCD and highlight LED light source. Its space resolution can reach 0. 04 mm/pixel and scanning speed can reach 100 mm/s for an industrial film. The transfer function curves of the system have been measured and the results indicate that its image gray resolution can reach 88 G/D at 4. 5D, and its dynamic range can be wider than 2. OD. In order to facilitate the evaluation of large welded structure, a panoramic evaluation algorithm is developed also. The algorithm includes image matching, image fusion and panoramic evaluation of the long linked film image.

纸膜双层缺陷检测的视觉成像光场设计

为实现包装盒纸质基底层和透明膜层缺陷的同步检测,开展了对纸和膜缺陷的同步成像研究。首先,分别建立了标准球面积分光场、椭球面积分光场和弧面积分光场模型,并利用COMSOL Multiphysics 5.6对3类光场进行射线仿真,对比分析了球面积分光场下射线角度均匀性及辐照均匀性,通过正交仿真优化椭球面积分光场参数;其次,在椭球面积分光场环境、亮场前打光环境、暗场前打光环境下对包装盒成像。与此同时,对包装盒的油污、抵触、开口、泡皱、破损5项常见缺陷依次进行物理检测和机器视觉检测,验证缺陷成像的有效性。试验结果表明,在椭球面积分光场下成像,图像对纸质基底层缺陷特征、透明膜层缺陷特征均有较好的呈现效果,图像上油污、抵触、开口、泡皱、破损的物理检出率分别为96.2%、92.5%、100%、95%、92%,异常检出率分别为98.6%、97.5%、100%、100%、98.4%,缺陷类别检出率分别为97.6%、96%、100%、97%、96%。研究结果表明,椭球面积分光场光路角度和辐照强度均匀,覆透明膜包装盒的缺陷特征呈现清晰,满足工业生产的检测要求。

Orientation and mobility control of 4HCB organic film for flexible X-ray detectors with high performance

In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.

宽幅胶片弊病在线检测系统

本文介绍了一套用于宽幅胶片生产线整理工序的弊病在线检测系统,该系统用来实时检测胶片表面常见的弊病。系统采用2台线阵CCD摄像机同步成像,940nm的LED面阵光源提供照明,利用单行处理、多行判断的快速弊病检测算法及时发现弊病。现场运行结果表明,系统能够完成对运行速度为90m/min,宽幅为1300mm的胶片表面弊病的检测任务。

用于光学薄膜缺陷检测的快速图像分割算法

为减少光学薄膜缺陷的漏检和误判,提高检测的快速性,提出了一种基于误差修正理论的图像分割算法。该算法接受带有随机误差的背景图像,并以各像素点灰度值残余误差与标准差的偏离程度作为分割依据,最终将缺陷检测转化为粗大误差判别。该算法使每个像素点都具有一个自动更新的最佳分割阈值,可改善全局或局部阈值分割不彻底的缺点。由于在系统初始化阶段标准均值背景图像已构建完毕,正常检测过程中仅需一次减法运算即可完成缺陷的分离;只有当背景图像灰度变化积累到一定程度时,才需要更新标准均值背景图像和标准差,因而算法总体运算量极小。实验结果表明,该算法能有效抑制图像噪声,克服由于目标与背景灰度级差极小而导致的分割困难,实现光学薄膜缺陷的快速检测。

用于生产线实时检测的胶片弊病检测仪

介绍了一种新型的用于生产线实时质量控制的胶片弊病检测仪。该检测仪采用 CCD红外高速摄影技术 ,通过滤波、分割、投影等快速图像处理算法 ,能够在 6 0 m / m in的速度下正确识别各种典型的胶片弊病 ,并对其位置进行准确测定。长期在线实验证明 ,该仪器运行稳定、抗干扰性强 ,检测精度符合生产要求 ,检出率在 98%以上 ,弊病定位相对误差小于 0 .0 8%。

CR技术与胶片射线照相技术检测能力的对比

对CR技术和胶片射线照相技术的记录介质结构、对比灵敏度以及缺陷检测能力进行了对比。结果表明,CR技术在对比灵敏度和缺陷检出能力方面,与胶片射线照相技术基本达到同等技术水平;CR技术具有比胶片射线照相技术宽容度大、曝光量小的优点,可大大提高工作效率,但CR技术对散射线较为敏感,在使用过程中应注意散射线的防护。

宽幅胶片弊病在线检测系统的研制

研制了一种基于CCD成像和数字图像处理技术的宽幅胶片弊病在线检测系统。在红外光源提供均匀照明的条件下,采用两台高分辨率线阵CCD摄像机对运转速度为90m/min、宽幅为1300mm的胶片实时成像,利用简化了的平滑去噪和边缘检测算法进行处理,并通过双阈值判据及时发现弊病,保存弊病位置信息和弊病图像。系统检测能力为横向80μm,纵向500μm,能够检测出各种典型的弊病。

低信噪比小检测目标光学薄膜缺陷图像分割算法研究

结合测量误差分析理论,提出一种新的高效的图像分割算法,将薄膜的连续图像采样过程看做等精度测量过程,背景图像认为仅存在随机误差,缺陷像素视做粗大误差。算法在起始阶段通过连续多次采样建立标准背景图像,并统计各像素位置的灰度标准差,然后将实时待测图像中的每个像素与标准背景像素进行减法运算,以3σ作为检测判据,从而将缺陷的检测与分离等效为粗大误差的判别与剔除问题;同时,考虑缺陷像素点的空间分布特征,将上述过程扩展到像素邻域范围,以二维分割阈值取代一维阈值,对离散噪声有明显的抑制作用。实验结果表明,该算法运算速度快,对低对比度图像适应性好,对噪声不敏感,可实现对不同种类缺陷的准确、完整分割,适于实时光学薄膜检测应用。

焊缝X射线探伤返修片的计算机打印技术

运用行式打印机输出焊缝X射线探伤返修片的方法,研究了最佳打印控制参数。结果表明:利用图象处理技术,对探伤返修片进行滤波,增强处理后,打印出的返修片分辨率高,视觉效果好,增强了图象的对比度,缺陷清晰,并改进了传统的返修片制作方法。

航空零件化铣胶膜激光刻线的视觉检测技术研究

设计并实现了一套针对航空零件化铣胶膜激光刻线的快速视觉检测系统。针对化铣胶膜刻线的特点讨论了检测路径的生成方法。研究了化铣胶膜刻线的图像处理方法和误差分析方法。该系统为化铣胶膜激光刻线提供了快速有效的数字化检测手段。

DR平板检测技术在螺旋埋弧焊管检测中的应用

简述了DR(digital radiography)平板探测器系统的成像原理。介绍了胜利钢管有限公司在螺旋埋弧焊管工业电视检测中引进的DR平板探测器系统的实际应用情况,并将该系统的成像效果与图像增强器、胶片等传统成像系统进行了对比。对比结果表明,DR平板探测器在螺旋埋弧焊管焊缝检测中具有明显的优势。最后指出了DR平板探测器系统使用过程中需要注意的一些问题。

X射线数字成像检测技术在防腐保温管道生产中的应用研究

大庆油田管道工厂化预制中常用X射线拍片检测方式对焊缝进行无损检测，这种检测方式存在许多局限，而采用X射线数字成像检测技术替代X射线胶片成像检测方式，可提高预制防腐保温管道的检测效率。先简要介绍了传统X射线拍片检测方式的局限性和X射线数字成像技术的基本原理，而后较详细介绍了X射线数字成像系统设备配置，最后对设备系统的综合性能进行了评价。研究工作最终达到了预期目标。

基于SIFT算法的射线底片拼接技术研究

由于射线检测技术自身技术特点和底片长度的限制,同一焊缝的射线检测信息通常需要多张相互搭接的底片方可完整显示,这不仅降低了检测结果的直观性,还存在底片被伪造的隐患。目前,监督检验人员对射线底片的人工辨识是防止底片伪造的主要手段,但同一工程中底片数量较多,势必造成人工辨识的效率和准确性较低。针对以上问题,采用SIFT算法对射线底片搭接区域特征的辨识与拼接技术展开研究,对含缺陷与不含缺陷的模拟试块射线底片进行实验,结果表明:SIFT算法能够有效匹配射线底片搭接区域的相似特征,并实现底片的完整无缝拼接,拼接准确率100%,此外,基于搭接区域特征和拼接结果实现底片伪造的快速辨识具有可行性。

胶片缺陷在线检测方法的研究

介绍了新研制的胶片质量在线检测系统。它采用 CCD红外成像和基于 Visual C++6.0的应用软件 ,综合运用低通滤波、边缘提取及投影检测等处理技术 ,对胶片缺陷的检测速度达到了 60 m/ min。实验证明 ,该系统运行稳定 ,检测准确率达到 98%以上 ,对于直径大于等于 1m m或直径虽小于 1mm但与背景有明显对比度的缺陷 。

图像分析技术用于微丸包衣膜厚度的在线测量

微丸包衣厚度是包衣质量评价的重要指标之一。为准确测量包衣厚度、提高包衣质量,开发了一种基于图像分析技术的微丸包衣厚度在线测量方法,即通过布置在流化床包衣腔周边的图像获取单元阵列拍摄包衣过程中微丸的实时图像,经图像处理后获得微丸的当前统计学平均直径,最后通过各时间点微丸直径计算适时的平均包衣厚度;针对因微丸粘连而在图像处理中出现伪轮廓的问题,提出了一种“比较坐标法”进行轮廓识别,可准确区别伪轮廓与目标轮廓;与传统的轮廓分离算法相比,“比较坐标法”能最大程度地保留原始轮廓区域的大小。分别使用直径0.6、1.0和1.4 mm的丸芯在流化床中进行包衣试验,然后测量经历不同包衣时长后颗粒的实时直径和包衣厚度,最后使用显微测量法进行了对比验证。结果表明,该方法能对流化床包衣过程中微丸的包衣厚度进行准确测量。