【作者】 曲晓峰；

【导师】 苑玮琦；

【作者基本信息】 沈阳工业大学 ， 检测技术与自动化装置， 2008， 硕士

【摘要】 圆筒在机械、能源、军事等领域有着大规模的应用。但在圆筒的生产过程中,一直采用传统的人工离线检测方法进行检测。为提高圆筒检测的速度,目前工厂急切需要能够实现圆筒在线检测的方法和系统。但由于圆筒的一端封闭,且生产现场温度高,现有的机器视觉检测方法和系统难以实现圆筒的实时在线检测。本文提出了一种基于视觉的一端封闭圆筒内壁几何参数在线检测方法,设计了一种特殊结构的成像机构,通过对激光反射所形成的反映圆筒内壁几何尺寸变化的光斑图像进行处理,从而获取圆筒内壁几何参数变化信息。根据机器视觉原理,对圆筒内壁进行检测,本文提出以激光三角测距方法为基础,使用新的成像方法的检测方法。该方法采用反射镜对激光光路进行变向,使激光垂直照射到圆筒内壁表面,形成反映圆筒内壁几何尺寸变化的光斑图像,采用三棱镜对激光光斑图像成像。该方法能够实现激光垂直射入,图像垂直传出。一方面,该方法可以完整地检测圆筒内壁,即使是接近圆筒封闭一端的远端也可以实现内壁检测;另一方面,该方法将成像所需的电子设备远离被测圆筒设置,可以满足高温生产环境的长时间工作的要求。根据新的圆筒检测方法,设计了圆筒检测系统。该系统由包括激光器、反射镜和三棱镜在内的成像系统、包括镜头、相机和采集卡在内的图像采集系统和机械系统组成。文中详细地分析了光路反射系统的组成,以半五角棱镜作为最终成像装置。文中详细地分析了镜头与相机之间的关系,并根据实际检测要求仔细地计算了各个参数,包括视角、视野、工作距离。根据计算,选择标准PAL制式的相机,配合图像采集卡可以达到768×576的分辨率,需要镜头视角小于7.84°。设计制作了能够固定激光器、反射镜、三棱镜和相机,且反射镜、三棱镜位置角度可调的机械装置。将各个组件与机械装置进行组装,能够实现实时在线检测的演示模型样机。就激光光斑中心定位算法进行了研究,设计了将检测系统采集到的光斑图像自动转化成光斑位置数据的程序。经过演示模型样机的实验表明,该系统对于内壁尺寸检测的分辨率可达0.1毫米/像素,内壁尺寸变化检测范围可达30毫米,完成单点的检测时间小于40毫秒。更多还原

【Abstract】 Cylinder has a large-scale application in machinery, energy, military and other fields. But in the process of cylinder production, traditional off-line methods of detection is using. To improve the speed of cylinder detection, cylinder on-line detection methods and systems are urgently needed to achieve at the factory. However, for the cylinder has one end closed and the temperature at the production scene is very high, the real-time on-line detection can’t be achieved with the existing testing methods and machine vision systems. A vision-based one end closed cylinder wall geometric parameters on-line measurement method is presented in this paper, an imaging agency with special structure is designed, by processing the spot image which is formed by the laser reflector and reflects the cylinder wall geometry change, cylinder wall geometric parameters change information is accessed.The principle of machine vision is adopted, to test the inner wall of the cylinder. The method proposed in this paper is based on the laser triangulation method, with a new imaging method designed. Reflector is used to change the light path of the laser in this detection method, to make laser beam to the cylindrical surface of the inner wall, a spot image which reflects cylinder wall geometry changes formed, prism is used to imaging the laser spot on the image. The vertical in of laser and vertical out of image can be realized by this method. On the one hand, the method can detect cylinder wall perfectly, even the detection to the wall near the cylinder closed distal end can be achieved. The other hand, required electronic imaging equipment is setup away from the measured cylinder, the requirements which is need for long time working in the high temperature production environment is met.According to the new cylinder detection method, the cylinder detection system is designed. The system consists of imaging systems, which includes laser, mirror and prism, image acquisition system, which includes the lens, cameras and image acquisition card, and the mechanical system. The composition the optical reflector system is analyzed in detail, eventually a half pentagonal prism is taken to be the imaging devices. In this paper, the relationship between the camera and the lens is analyzed in detail, various parameters including the angle of view, field of view and working distance in accordance with the actual requirements is carefully calculated. According to the computation standard PAL camera which can reach 768×576 resolution when working with image acquisition card is selected, camera angle is need to be less than 7.84°. The mechanical devices has been designed and produced to the fixed laser, mirror, prism and cameras, with the position and angle of the mirror and prism adjustable. Demonstration model prototype which can achieve real-time on-line cylinder detection is made by assembling all components and mechanical devices.Laser spot positioning algorithm is studied in this paper, and program which can automatically change the spot images collected by the detection system to spot location data is designed. After the experiments of demonstration prototype model, it is showed that the resolution of the detection system of the inner wall can be 0.1 mm/pixel, wall size change detection range is not less than 30mm, and the detection time of one spot is less than 40ms.更多还原