【作者】 樊帆；

【导师】 石晓龙；

【作者基本信息】 华中科技大学 ， 系统工程， 2009， 硕士

【摘要】 钢铁质量检测一直是钢铁生产的一个重要环节,对钢铁连铸坯的生产效率和生产质量都有着重大的意义。钢铁连铸坯表面缺陷检测作为一种重要的钢铁质量检测技术,一直是钢铁生产领域关注的热点。近些年钢铁连铸坯表面缺陷评级技术中应用最为广泛的技术冷酸蚀表面缺陷检测法在准确性上有很好的效果,但由于该技术仍采用人工来进行,在检测效率和精确性上已逐渐无法满足生产的需求。本文针对连铸坯冷酸蚀表面缺陷在自动化评级上的应用需求,提出了基于数字图像处理技术的解决方案,实现连铸坯冷酸蚀图像的缺陷评级自动化。本文着重对该自动评级技术中的图像预处理过程进行了深入研究。图像预处理旨在通过有针对性的处理,实现图像在各方面统一化,消除影响图像特征提取的不利因素,为后续特征提取的工作提供必要的支持。对于图像预处理过程中,重点对光照补偿、图像分割进行了研究。针对图片中偏光现象严重的情况,本文通过对直方图均衡化法、光照探测补偿法的算法及效果的研究比较,提出了基于以上两种方法的改进的光照补偿算法,有效克服了偏光现象对连铸坯图像的影响,保证了图像分割的有效性。针对图像预处理中的图像分割问题,本文对不同的缺陷分别提出了研究算法,根据中心偏析、中心疏松的离散性特点,提出了全局阈值、局部阈值结合基于邻域的杂散点分割法的算法;针对内裂、特裂、角裂缺陷的表现特征和评级方法,提出了全局阈值结合区域生长法、基于边界跟踪的图像分割法,并在效率上进行比较分析。更多还原

【Abstract】 Steel quality inspection , which has always been an important process in the production of iron and steel , is of great significance to the efficiency and quality of Continuously Cast steel billet production. Steel billet surface defect detection , as an important techniques of Steel quality inspection,has been the focus in this field .In recent years the most widely used technique of Steel billet surface defect detection is Cold Acid Etching ,has proved to be efficient, however ,this technique , which is a manual job,can not meet the needs of the efficiency and accuracy.According to the requirements of automatic rating of the Steel billet surface defect by Cold Acid Etching,this paper propose a solution based on the techniques of digital image processing , achieving the purpose of the accurate automatic rating . This paper focus on the process of the pre-processing in this technique and carry out an in-depth study of it.Image Pre-processing process is designed , with efficient operations, to make the images normalized , to eliminate the adverse effects against the Feature Extraction, to provide the necessary support to the Follow-up Feature Extraction process . In the image pre-processing process , this article mainly focus on the illumination compensation and the image segmentation . Against the serious problems caused by Polarized light,this article provide two Algorithms ,Histogram equalization and the illumination detection and compensation , and take a study and comparison . Basing on these two Algorithms , this paper provides an improved , successfully overcome the impact to the continuous casting steel billets caused by the phenomenon of polarized light. In the image segmentation process , this paper provide different algorithms for each defects. According to the characteristics of center segregation and center porosity , the paper provide the overall threshold and Local threshold combined with algorithm of Neighborhood-based spurious points segmentation; According to the characteristics of outlooks and rating rules of internal crack. corner crack. Special crack , the paper provides overall threshold Algorithm combined with edge-detection based segmentation Algorithm and Algorithm based on seeded region growing theory ,and do some analysis and comparison between them in efficiency .更多还原