【作者】 李琎；

【导师】 曲学军；

【作者基本信息】 沈阳航空工业学院 ， 航空宇航制造工程， 2009， 硕士

【摘要】 在飞机制造中,复杂轮廓表面的加工与测量技术水平已成为一个国家航空科技水平的标志之一。虽然包含自由曲面的飞机零部件与模具的数控加工技术取得了显著进展,但其形状检测和质量保证一直是一个自动化程度很低的过程。本文对飞机零部件的数字化检测技术进行了讨论,提出了在CMM精确控制下的线结构光与计算机视觉相集成检测方案,并对其中的关键技术并进行了深入研究。主要研究内容包括:1.根据飞机零部件的结构和检测要求,构建了多传感器检测规划模型,分配CMM接触式测量、线结构光视觉测量系统和双目视觉测量系统的检测任务,获得完备的零件外形数据。建立复杂形状质量评价方法与指标,将所获测量数据与零件数字化模型进行比较,来完成飞机典型部件与零件的质量检测。2.实现了CCD摄像机、图像采集卡、线结构光激光传感器以及供电电源等设备与计算机系统的连接,编制了获取图像数据的接口程序,实现了摄像机的拍摄参数的配置,图像拍摄模式、帧速率以及图像文件的保存等功能。3.研究了图像处理的算法,包括图像数据的随机噪声的剔除,激光光条图像的分割以及光条中心点的提取。在随机噪声的剔除算法中,使用一种改进的基于5×5滤波窗口的中值滤波技术,大大简化了后续的图像处理过程,并降低了条纹中心提取的误判率,从而提高了测量数据的可靠性。4.在建立的基于小孔成像的摄像机成像数学模型中,考虑了径向畸变误差对测量数据的影响,在此基础上实现了一种基于两步法的摄像机标定方法。该方法只需对标定模板进行一次拍摄,即可获得摄像机内外参数。通过投影面上三个不共线点的坐标来确定结构光平面方程,结合前面获得的标定结果,即可完成线结构激光传感器的标定。5.使用VC+6.0开发了实验系统。通过获取的计算机图像信息得到了测量数据的三维信息,以此验证系统的测量精度。更多还原

【Abstract】 In aircraft manufacturing, techniques of processing and detecting complex surfaces have become a symbol of scientific and technological level of a country. Although CNC machining technology of aircraft parts and dies which contain free-form surfaces have made remarkable progress, automation degree of detection and quality assurance of above them has always been very low. In this paper, digital detection technology of aircraft parts and components is discussed, detection scheme which integrate the line structured light sensor and machine vision under CMM control is put forward, and key technologies of above technique are researched in depth.Main works of us focus on following parts:1.According to structure feature and detecting requirement of the aircraft parts and components, a multiple sensor detection model is set up, which distributes detection tasks among CMM contact measurement, line structured light visual detection system and binocular vision measurement system in order to get complete part appearance data. Quality evaluation method and indicator of complicated shape is also established, which can be used as guidelines to compare measuring data with digital produce model, thus quality detection of typical aircraft components and parts can be realize.2. Connection between devices such as CCD camera, IEEE1394 card, line-structure laser senor, power supply with computer system is established, interface programs used to getting image is coded, which can set parameters, customize model of shoot and frame-ratio, and save the image files.3. Image process algorithms are studied, which include eliminating random noise of image data, devising laser-stripes image and getting center points from these stripes. An advanced median-filter arithmetic based on 5×5 windows is used to eliminate random noise, thus simplify latter image process, reduces misjudgments in the process of getting center points and increasing the reliability of measurement data. 4. Mathematical model of CCD camera based on pin-hole imaging theory set up by us has considered the influence of radial distortion error towards measurement data, based on above theory a calibration method which have two main steps is provided. Only one shoot to calibration model is needed to get all the inner and outer parameters of the camera. Equation of projection plane is acquired by three non-linear points, combined with above results the calibration of line structured light senor can be deduced.5. An experimental inspection system is developed with VC++6.0. Through this system, 3D digital information of measuring data is derived from image information, and then precision of this system is verified by these data.更多还原