【作者】 刘斌；

【导师】 孙长库；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 自动光学检测技术具有检测方法先进、检测速度快、自动化程度高等优点,可在线完成物体表面空间三维坐标的测量。本文采用线结构光视觉技术建立了微小三维尺寸(0.01-10mm)自动光学检测系统。论文研究的主要内容和创新技术有:1.通过引入光平面和测量坐标系的夹角参数,建立了传感器的DLT改进数学模型和多项式模型。2.研究了传感器两步标定方法,第一步将数学模型中的参数标定完成,第二步确定光平面与测量坐标系的夹角的数值。该方法可直接构建传感器的测量坐标系,过程简单,标定结果可靠,适合现场实施。3.对传感器标定和安装过程中可能产生的误差进行了分析。提出了对标定构建的测量坐标系与实际测量坐标系偏斜造成的误差进行修正的模型,研究了使用一标准块对修正模型参数进行校准的方法。4.研究了光强自适应调整方法,应用于研制了电路板锡膏三维测量系统,保证了光条图像的效果,降低图像处理复杂度的同时提高了光条中心提取的准确度。对该系统进行了重复性测量实验,结果表明系统的高度测量精度可达±1?m,并在现场进行了实际测量实验。5.研究了椭圆弧光条图像的径向灰度重心提取的方法,应用于研制了微小直径高精度测量系统,提高了系统的测量精度。对该系统进行了重复性测量实验,结果表明系统的测量精度可达±1.4?m。使用该系统对发动机旋转叶片边缘曲率半径进行了实际测量。更多还原

【Abstract】 Automatic Optical Inspection (AOI) has advantages of advanced inspectionmethod, high measuring speed and high degree of automation. It can be applied toobtain 3D coordinate of the object surface points at the scene. Based on structuredlight vision technology, an AOI system for 3D micro size (0.01-1mm) measurement isproposed in this dissertation.The major contribution and innovations of this dissertation are as follows:1. Two mathematical models of the sensor are studied. One is the improvedmodel based on Direct Linear Transform (DLT). The other is the polynomial model.And the angle between the light plane and the measuring coordinate system isintroduced.2. A two-step calibration method for the mathematical models is studied. In thefirst step, the parameters of the mathematical model are confirmed. In the second step,the angle between the light plane and the measuring coordinate system is calculated.This method can build the measuring coordinate system directly. The process of themethod is simple and stable. It is suitable for on-site calibration.3. The errors, which maybe occurred during the calibration or the installationprocess of the sensor, are analyzed. The correction model is proposed, which canreduce the error caused by the deflection between the measuring coordinateconstructed by the calibration and the actual one. The calculation method using astandard part for the parameters in the correction model is studied.4. The adaptive adjustment method of laser light intensity is proposed, which isapplied in the developed high-precision measuring system for 3D size of solder pastesprinted on the PCBs. By using the method, the light-stripe image effect is guaranteed.And the accuracy of the light-stripe center extraction is improved while thecomplexity of image processing is reduced. The repeatability precision of the systemwas tested. The experimental result proved that the measuring precision along theheight direction is±1?m. The system was also tested on-site.5. A novel grayscale barycenter extraction algorithm along radial directions isproposed, which is applied in the developed high-precision measuring system formicro diameter. The accuracy of the measurement result can be improved obviouslyby using the algorithm. The repeatability precision of the system was tested. The experimental result proved that the measuring precision is±1.4?m. At the scene, thesystem was applied to measure the curvature radius of metal blades.更多还原