【作者】 刘建华；

【导师】 单亦先； 任旭虎；

【作者基本信息】 中国石油大学 ， 信号与信息处理， 2008， 硕士

【摘要】 构造物理模拟实验是研究地质构造的一种有效方法,是帮助地质学家认识构造变形过程、研究构造形成机制的重要手段。目前实验中实验体顶面检测技术主要采用照相、摄像、目视或用直尺简单测量等定性测量方法,测量精度低,而且由于实验介质多采用易变形的砂体,用接触式测量方法获取顶面信息时,易破坏顶面面形。为了地质学家准确分析构造变形信息,需要采用非接触测量方法获取模拟实验顶面信息。鉴于光学三维测量技术具有非接触、测量速度较快、精度较高等优点,论文采用了基于光学三维测量技术的相位测量轮廓术来完成实验体顶面变形信息的测量,针对实验体顶面变形信息复杂的特点,对测量中的关键技术,如相位展开算法、测量系统标定等环节进行了深入的研究,具体工作如下:1.论文在分析了相位展开的基本原理、主要相位展开方法的基础上,针对实际测量时,由于砂箱边界阴影、噪声等因素的影响,利用传统的相位展开算法无法精确获取实验体三维形态,对相位展开过程中噪声引起相位误差传递的机理进行了研究,借鉴传统质量图,提出了一种新的质量图(背景梯度-相位导数偏差质量图),并结合基于可靠性排序的相位展开算法对模拟物体和实际物体进行了相位展开,实验结果表明该算法较好的避免了由噪声引起的误差传递问题,证实了算法的可行性和有效性。2.系统标定是进行三维面形测量的必要前提,标定分为两部分:Z坐标标定和(X,Y)坐标标定,Z标定用于建立物体高度和相位差的对应关系,(X,Y)标定就是建立起图像像素坐标与物体世界坐标(X,Y)的对应关系。文中研究了系统标定的数学模型,借鉴成熟的标定方法和图像处理技术,利用基于Harris角点检测的亚像素定位技术提取角点,插值拟合的隐式标定方法进行相位-高度映射关系的标定,进一步提高了测量系统的标定精度。3.论文从理论上分析了三维面形测量系统的误差来源,结合实际情况,搭建了基于相位测量轮廓术的实验系统。该系统利用计算机控制投影仪产生结构光,由摄像机获取变形的结构光图像,然后采用相位测量轮廓术进行数据处理来获取构造模拟实验体顶面信息,实验结果表明采用相位测量轮廓术进行构造物理模拟实验顶面测量能够获得比较满意的结果。更多还原

【Abstract】 The tectophysics simulating experiment is an effective method for researching geological structure, as it plays an important role in the research of the transforming progress and forming mechanism of tectonic deformation. The typical top surface measurement technology presently used in tectophysics simulating experiment such as photograph, imagery, eye estimate and so on is not good in measurement accuracy. And it can easily destroy the top surface of ductile sand body that is widely used in experiment, when we use contacting method of measurement to obtain information of top surface. And optical 3-D Measurement technology provides the non-contacting method for geologist to obtain accurate information.The thesis adopts Phase Measurement Profilometry based on Optical 3-D Measurement technology because of it’s advantages of non-contacting, quick measuring, high accuracy and so on to accomplish measurement of top surface information. In allusion to the complex features of top surface deformation of the experiment body, we pay attention on key technology such as phase unwrapping algorithm, system calibration and so on. What is contained in the thesis is as follows:1.By analyzing the fundamental principle of phase unwrapping and main unwrapping algorithm and studying up on the phase error propagation problems caused by noise, the thesis proposes a new quality map based on the background gradient and phase derivative variance to solve the lower measurement accuracy problem caused by sand box border shadow and top surface deformation of the experiment body, then unwraps simulation data and real data using the reliability ordering phase unwrapping algorithm. The new method is feasibility and effectiveness because it can better avoid the error propagation.2.System calibration is essential in optics 3-D shape measurement. Z and (X, Y) coordinate calibration are two parts of it. Z calibration means to find out the relationship between height and phase difference. And(X, Y) calibration is to build a correspondence between image coordinate and world coordinate. The thesis studies up on the mathematical model of system calibration, traditional calibration methods and image processing, then adopts sub pixel allocation technology of harris comer detection to locate corner and the implicit calibration method of interpolating approximation to accomplish the phase-height mapping. The result shows that this method can further improve accuracy of system calibration.3.The thesis theoretically analyzes the system errors and designs an experimental system for PMP based on the result of theoretical analysis and computer simulation. The system is fulfilled with a computer controlling projector to display structured light and a CCD camera to detect the deformed image, and then obtains top surface information by processing data with PMP. The result shows that the method used in tectophysics simulating experiment can obtain good effectiveness.更多还原