【作者】 沙吉乐；

【导师】 叶声华；

【作者基本信息】 天津大学 ， 测试计量技及仪器， 2003， 博士

【摘要】 本文研究了基于立体视觉原理和液晶光栅投影技术的三维视觉测量系统。该系统结构简洁，便于携带，可以实现现场三维形貌（自由曲面）的非接触，快速的测量。系统利用液晶投射空间规则编码点图案到被测曲面，由双目传感器接收经曲面调制的测量图像，经专用设计的图像处理软件，采用粗、细匹配技术精确获得特征匹配点，利用视觉技术得到三维数据点阵。采用了NURBS理论对数据点阵进行曲面插值，获得NURBS参数曲面方程，为工业自动化生产提供标准接口。论文中主要研究内容如下：1．研制了基于液晶光栅技术的新型双目视觉传感器，无需硬件改动，只需改变软件即可实现点扫描、线扫描和光栅编码型视觉传感器的功能。分析了双目传感器的测量精度，优化了传感器设计。2．设计了光学投影系统，分析了投影系统的测量景深与测量范围的关系，设计了测量系统控制模块，构建了实验室条件下的测量系统。3．将空间规则点图案投射到被测物体表面形成特征点，然后利用空间二分编码粗略获得空间特征点（称为粗匹配），再利用自相关技术、质心技术和角点技术精确获得空间特征点的图像坐标（称谓细匹配）。利用已经精确标定的双目传感器获得特征点的三维坐标。4．设计了针对液晶特点的图像处理专用软件，采用了中值滤波、自动化阈值、形态学技术对液晶图像进行处理，实现粗、细匹配方案。5．根据获得的三维数据点阵具有拓扑矩形的特点，研究了利用NURBS理论的曲面重构技术，实现测量数据与工业生产标准接口。更多还原

【Abstract】 A 3D vision measuring system based on stereovision theory and LCD grating projection technique is studied in this thesis. The system is brevity and portable, it can get three-dimensional coordinates of the free form at field. The measuring is non-contact and quickly. Regular point images of LCD are projected to the measured surface. The images modulated by the surface are received by binocular vision sensor. A special image processing software is developed to deal with the LCD images. Characteristic points are obtained accurately by rough-precise match technology. The coordinates of 3D data points are calculated by binocular sensor that is calibrated precisely. These points define a surface equation based on NURBS theory. It supplies interface to industry manufacture. The main works of this thesis are summarized as follows:1. A new binocular vision sensor based on LCD grating technique is developed. It has the functions of three traditional vision sensors: point scanning, line scanning and grating code. The deficiency of the sensor is analyzed. The structure of the sensor is optimized.2. Optical rejection system is designed; the depth of field of the projection system is calculated. The control module of measuring system is designed. An experimental system is developed.3. Characteristic points are established through projecting images of regular points to measured surface. Space dimidiate coding method which is called rough match and correlation technology, centroid technology, corner detect technology which are called precise match are used to acquire characteristic points accurately. The coordinates of these points are calculated by binocular vision sensor that is calibrated precisely.4. A special image processing software is programmed according to the characteristic of LCD image. Median filter, auto-threshold and morphological technology are used for rough-precise match.5. NURBS surface reconstruction method is studied. The 3D data points obtained above are topological rectangles, which are required by NURBS theory. The reconstruction using NURBS method supplies standard interface for industry manufacture.更多还原