【作者】 余良忠；

【导师】 龙伟；

【作者基本信息】 四川大学 ， 机械制造及其自动化， 2003， 硕士

【摘要】 随着现代航天航空技术的迅速发展，球形工件上各种圆孔的加工位置精度要求也越来越高。相应地，对球面圆孔位置的检测精度提出了很高的要求，并且检测时要求采用非接触测量形式。 本文提出的测量系统使用当今先进的光电技术和数字图像处理技术实现了球面孔系相对位置的非接触式测量。测量系统利用光学成像技术把球面孔系坐标的三维测量转换为二维测量，使用线阵CCD和光栅传感器与机械运动机构相配合以扫描方式对球面圆孔进行图像采集，通过计算机数字图像处理技术对图像进行圆孔中心识别，并通过软件处理的方式把二维测量、计算结果转换为三维测量结果。 本文介绍了球面孔系坐标非接触测量系统组成结构、原理和工作过程，以及系统使用到的CCD、光栅传感器和轴角编码器等光电技术。同时介绍了步进电机单片机控制系统的软硬件设计原理与方法，详细分析了上位计算机如何控制前端单片机控制系统和图像采集系统实现对球面圆孔的图像采集，并结合球面孔系坐标的测量时间和精度要求提出了四种具有一定针对性的图像采集方法：“全程采集”、“双段采集”、“变速采集”和“局部采集”。同时介绍了中值滤波、二值化以及圆孔边缘提取等常用数字图像处理技术，并着重阐述了适合于本测量系统的“弦中心法”、“三点定圆法”和“最小二乘圆法”三种圆孔中心识别方法。最后建立了球面孔系坐标的几何模型及算法，实现二维测量到三维测量的转换，并以详尽的实验结果对本测量系统所能达到的精度进行验证。更多还原

【Abstract】 The fast development of spaceflight and aviation technology leads to rigorous precision requirement of the machining position of circular hole on the spherical work-piece. Accordingly, it requires much higher detecting precision on the position of spherical circular hole, and adopting noncontact measuring methods when detecting.The measurement system raised by this paper used some advanced photoelectric and digital image processing technology to measure the relative position of the spherical circular hole series in noncontact method. This measurement system transforms the three-dimensional measurement on the coordinates of spherical circular hole series to planar measurement by the optical imaging technology. By the digital image processing technology, this measurement system software identifies the center of circular hole in the image, which is captured by the measurement system by means of mechanical scanning using linear CCD and raster sensor cooperating with mobile mechanism. The planar measure and calculating results are converted into three-dimensional measure results automatically by the measurement system software.This paper firstly introduces the elements and working principle and process of the measurement system, together with some photoelectric technology used by this system such as CCD, raster sensor, and photoelectric rotary encoder. The designing principle and method of software and hardware for the single-chip control system of step motor are secondly introduced in the paper. Thirdly, this paper illustrates how the upper computer to control the single-chip control system and the imagecapturing system in the foreground to accomplish the image capturing process of the spherical circular hole in mechanical method, and aiming at the time and precision requirements of the project, it brings up four kinds of image capturing methods: "Full Area Capture", "Double Segment Capture", "Variant Speed Capture", and "Partial Area Capture". Fourthly, this paper presents some common digital image processing technology, including median filter, binary threshold and extracting of circular hole edge, and besides, expounds three kinds of recognising method for the center of circular hole, i.e. "Circle Chord Center", "Circle Fixed by Three Points", and "Least Square Circularity", according to this measurement system. Finally, based on the geometric model and arithmetic for the coordinates of spherical circular hole series, this paper demonstrates how to convert the planar measuring and calculating results to three-dimensional measuring results, and exhaustive experiment results validate the precision this measurement could achieve.更多还原