【作者】 丁金明；

【导师】 曲兴华；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2004， 硕士

【摘要】 质量是影响企业生存和发展的核心要素之一。在生产过程中对产品的质量进行检测，并将检测所获得的信息用于自动控制是实现这一目标的重要手段。本课题的研究对象是金属镀层工件表面上的多种随机缺陷，目的是把有缺陷的工件检测出来，分选出来，从而实现质量检测的目的。由于金属镀层表面对光的反射特性比较强，强反射复杂表面上随机缺陷的自动检测是一项重要的研究课题，也具有一定的技术难度。在本课题前一阶段的研究中，在研究工件表面照度与缺陷检测难易程度的关系时，提出了缺陷显现力的概念；在照明光源的选择和图像处理方法上也做出了一定的研究。本论文继续研究照明技术和图像处理方法，针对各种缺陷的自身特点提出了不同的算法，在前人研究的基础上，结合CCD光电检测技术、计算机图像处理技术与自动控制技术，初步设计了金属镀层工件表面缺陷的面阵CCD自动检测系统。论文的主要研究内容有：研究了金属镀层工件表面缺陷的特征，发现缺陷的显现程度与光源照明系统、工件到光源和CCD的距离等都有关系；研究并制作了几种光源，最后设计制作了圆台形LED均匀散射光光源，为采集图像提供良好的照明条件，并改善了图像质量；初步设计了分选机构和翻转机构；针对涉及到的各种缺陷，提出相应的检测方法，在实验的基础上研究了阈值分割的算法，解决了本课题所需要的去除圆周、圆度判断和判断最大直线长度的算法；对大量实验数据进行分析，并提出了改进措施。更多还原

【Abstract】 Quality is one of the essential factors that affect the survival and development of an enterprise. For this purpose, one important means is to automatically inspect material and product during the process of produce and feedback the inspection information into quality control. What this thesis being studied is the stochastic defects on the surface of electroplated workpieces. We expect to make out all the defective workpieces and take them off and let the quality detection come true. The reflection of the electroplated workpieces surface is very strong. Automatic detection for defects on strongly reflective surface is an important research thesis, which is not easy to solve too. This thesis have been studying for quite a long time. When studying the relation of the illumination of workpiece surface and the difficulty to detect defects, the concept of defects’ expressivity was brought out. My former had also studied the illumination system and many methods in image processing. This paper continue studying on the illuming system and image processing methods and make out all detection methods for each kind of defects. On the shoulder of my former, combined with CCD photoelectricity inspection and image processing and automatic control technique, This paper presented out an methods and auto-detect system for detecting the defects of workpieces’ electroplated surface. The main content of this thesis are:1.In research of the character of the defects of workpieces’ electroplated surface I found that the Defect Expressivity is related to not only the illumination system but also the distance from workpieces to lamp-house and CCD.2.After studied and designed several kind of lamp-house I finally designed a conoid LED illumination system with uniform scatter light, which provides a good illumination condition for CCD and helps improving the quality of images.3.The pilot study on disparting machine and overturn machine.4.Putting forward different detecting methods for different defects. Based on experimentation I have studied the image binaryzation arithmetic and solved the arithmetic of getting rid of white circle and circularity judging and line’s max length judging. <WP=4>5.Analyzing the vast experimental data and proposing the betterment suggestion.更多还原