长悬臂三坐标测量机测端抖动实时修正系统

长悬臂三坐标测量机是用来在线测量工字钢结晶器内腔尺寸的，测量运行过程中，由于长悬臂及测杆的弱刚性和各轴传导结构的非理想性，造成测杆端部的空间抖动，直接影响测量精度。论文结合有限元分析了产生抖动的原因，基于面阵CCD和图像处理技术，建立检测系统并建模，实时检测测头触发瞬间测杆端部在空间3个方向的抖动位移，在VC＋＋6．0环境下编写软件，通过软件计算实时修正抖动对测量精度的影响。并通过试验验证了该系统的实用性。     

Exploring thermal spray gray alumina coating pore network architecture by combining stereological protocols and impedance electrochemical spectroscopy

Complex multiscale pore network architecture characterized by multimodal pore size distribution and connectivity develops during the manufacture of ceramic thermal spray coatings from intra- and interlamellar cracks generated when each lamella spreads and solidifies to globular pores resulting from lamella stacking defects. This network significantly affects the coating properties and their in-service behaviors. De Hoff stereological analysis permits quantification of the three-dimensional (3D) distribution of spheroids (i.e., pores) from the determination of their two-dimensional (2D) distribution estimated by image analysis when analyzing the coating structure from a polished plane. Electrochemical impedance spectroscopy electrochemically examines a material surface by frequency variable current and potential and analyzes the complex impedance. When a coating covers the material surface, the electrolyte percolates through the more or less connected pore network to locally passivate the substrate. The resistive and capacitive characteristics of the equivalent electrical circuit will depend upon the connected pore network architecture. Both protocols were implemented to quantify thermal spray coating structures. Al₂O₃-13TiO₂ coatings were atmospherically plasma sprayed using several sets of power parameters, are current intensity, plasma gas total flow rate, and plasma gas composition in order to determine their effects on pore network architecture. Particle characteristics upon impact, especially their related dimensionless numbers, such as Reynolds, Weber, and Sommerfeld criteria, were also determined. Analyses permitted identification of (a) the major effects of power parameters upon pore architecture and (b) the related formation mechanisms. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

基于改进C-V方法的焊接图像识别

基于简化的Mumford—Shah水平集图像分割模型，Chart—Vese提出了不依赖于图像边缘的水平集图像分割算法（C～V方法）。文中对该算法进行了深入研究，指出了原方法存在的缺陷，即处理的图像必须具有比较明显的特征，分割目标过多且较为分散时则很难得到理想的结果，每次迭代过程都需要对所有的图像数据进行计算，比较费时。根据焊接图像本身的特点给出了三点改进，即强化特征模型的修正、多尺度快速算法和全局特性抑制。应用改进的算法，进行了模拟对比试验和真实熔池图像识别的试验。结果表明，该方法能识别出焊接图像连续轮廓，提取有用信息，具有良好的适应性，同时为复杂图像的特征物体目标提取提供了可行的思路。     

面状缺陷超声B扫描检测图像增强研究

针对面状焊接缺陷超声B扫描检测图像受噪声污染造成的质量下降问题,利用多尺度小波分析方法,对超声B扫描图像进行了增强处理.分析了缺陷信号和噪声的小波变换特性,分别在软、硬阈值函数条件下,采用固定阈值、Stein无偏似然估计阈值、混合型阈值、极大极小准则阈值等方法进行了信号增强处理,比较了不同阈值方法小波变换的处理效果.结果表明:小波变换方法能有效地提高超声B扫描图像质量,硬阈值条件下固定阈值小波变换方法的图像增强处理效果较好.     

铝液充型过程水模拟计算机可视化技术

采用可视观察方法研究了铝液充型过程的二维流动状态,并与水模拟实验进行了对比分析,通过调整水粘度来保证水模拟过程与铝液充型过程的相似性.以PIV技术为基础,运用数字视频处理中的运动补偿技术,选用NCCF准则和三步搜索法对低压铸造浇注系统水模拟充型过程的内部二维流场进行了计算和分析;运用边缘检测及提取技术,选用Roberts边缘检测算子对低压铸造浇注系统水模拟充型过程的二维表面流场进行了计算和分析,实现了水模拟过程的量化分析.     

Morphological analysis and classification of types of surface corrosion damage by digital image processing

This paper examines a new concept of corrosion surface damage analysis by using the digital image processing. Corrosion phenomena are analyzed using a digital value for morphological surface damages instead of electrochemical methods. Initial images are characterized by three categories: color, texture and shape features. To calculate corrosion surface damages color we use the interpretation of HIS model. For the texture attributes, the method of co-occurrence matrix is used. Five types of corrosion damage are examined. Multidimensional scaling procedure is used to define the classification plane. This study suggests a probabilistic method of decision-making. This analysis develops a method for automated identification system of corrosion damages and is supposed to be more advantageous than that of electrochemical techniques.     

MAG焊熔池图像特征及可用信息分析

针对MAG焊焊接过程的特点,采用被动式视觉传感的方式,利用近红外CCD摄像机,配合1064nm窄带滤光片和0.1%中性减光片组成的复合滤光系统,很好地排除了弧光的干扰,采集到大量高清晰的MAG焊短路过渡、射滴过渡、射流过渡熔池图像.利用数字图像处理技术对熔池图像进行图像处理,并提取出反映焊接质量的图像特征信息.对于单幅熔池图像进行了灰度分析,并提取了三条熔池图像等值轮廓线;对于连续多帧熔池图像,提出了利用熔池图像差影检测和熔池图像平均灰度来研究MAG焊焊接过程的新思路,为熔化极气体保护焊焊接过程质量控制奠定了基础.     

牙科着色玻璃渗透氧化铝陶瓷的性能研究

在1400℃下熔融2h制备4种定制颜色的着色渗透玻璃，并将玻璃于1120℃渗透入预烧结氧化铝多孔基体，采用分光光度计测定渗透后的透射比和颜色参数，渗透后的复合材料作三点弯曲强度及断裂韧性测试，断裂面进行扫描电镜观察。结果表明：玻璃渗透后铝瓷的颜色参数范围：L^＊：68．80-78．44，a^＊：1．32～4．75，b^＊：16．86-21．86。三点弯曲强度为（420-27．72）MPa，断裂韧性为（3．70-0．13）MPa·m^1/2。     

玻璃模具喷焊时温度分布规律研究

利用G90-SAT红外热像仪测量了玻璃模具喷焊时的温度分布。结果表明，无论是同一点不同时刻的温度还是同一时刻不同截面的温度变化均十分复杂，工件表面每一点的温度都遵循低→高→最高→高→低的变化规律，喷焊重熔时温度最高。热喷焊是一个快速加热、快速冷却的过程，喷焊过程中，玻璃模具表面的温度存在着不均匀性及不同时性。     

镀铬层表面等离子束流加热区视觉信息检测试验

论述了视觉传感技术的特点和研究现状。针对镀铬层固态表面传热及光路特点，选取了普通CCD摄像机，利用固态表面对电弧的反射光和加热工件自身的辐射光，在近红外波段取像的视觉采集方法。结合近红外光谱特点和CCD摄像机的光谱响应度变化趋势，在980nm波长的窗口区域提取到了清晰的视觉图像。分析了镀铬层固态表面等离子束流加热区图像的成像机理，在对加热区图像特征进行分析的基础上对图像进行了处理，提取出了有效信息。