【作者】 宁乔；

【导师】 于强；

【作者基本信息】 中国科学院研究生院（空间科学与应用研究中心） ， 计算机应用技术， 2008， 硕士

【摘要】 空间流体实验具有无人操作的特殊性,需要对监控图像进行实时处理,得到观察对象的特性参数(例如体积、表面积等),再通过控制系统控制观察对象的特性。本课题研究了利用CCD捕捉到的液滴灰度图像,分析求取液滴的表面张力、接触角、体积等物理参数的方法;同时通过反馈控制系统,维持液滴的大小,从而求取液滴的蒸发速率。该系统主要由图像采集,图像处理,反馈控制三个部分组成。其工作原理是对CCD采集到的液滴图像进行分析,得到液滴的物性参数,控制注液器动态注入来维持液滴的大小,由此得到单位时间内的注入量,也即液滴蒸发速率。或通过对液滴图像几何尺寸的计算,得到单位时间内液滴的变化量,进而得到液滴的蒸发速率。针对液滴的灰度图像,利用边界提取、域值分割等图像处理方法,得到液滴的基本轮廓。建立基于液面像素点坐标的拉普拉斯方程,运用牛顿-拉夫逊法、龙格-库塔法、坐标轮换法,遗传算法等多种数值方法,对液滴的边界进行拟合,寻求最优的轮廓拟合点。根据最优的拟合点,确定液滴的物理参数。选取了牛顿法和一维寻优相结合的算法进行轮廓拟合的,并和Rotenberg等人提出的算法进行了比较,证明了该方法收敛速度较快,拟合精度较高的特点。该方法是实现空间蒸发液滴热毛细对流和接触角测量实验的一项关键技术,也是直接为我国“实践十号”返回式科学实验卫星上的“蒸发与流体界面效应空间实验研究”项目而专门开发的,同时也可以运用到非接触测量的实验场合。更多还原

【Abstract】 The liquid experiment in space needs intelligence to deal with the surveillance image right away to obtain the characteristics of object. A method is investigated to analyze the physical feature of a drop, such as surface tension, contact angle volume and evaporation velocity through fitting contour of the drop picture.The system is constituted of 3 parts: image acquisition, image processing, and feedback control. Analyzing drop pictures from the CCD camera, the physical features of the drop could be obtained, and evaporating volume could be calculated from the geometry differences between two pictures. To maintain the drop volume, drive the injector to inject dynamically. The evaporation velocity could be calculated by the evaporating volume during unit time.From the grey picture, generally contour of a drop is obtained by Edge detection and Segmentation algorithms. Constructed the Laplace equation of the drop, made contour approach process through comparing and using Newton-Raphson method, Runge-Kutta method,coordinate rotator method and GA. With the help of contour approach, physical feature of the drop is obtained. A new algorithm which nests Newton-Raphson method with One-dimensional optimization is presented. Compared with the original algorithm raised by Rotenberg, the new one reached convergence quickly with high accuracy. It is a key technology of the special experimental system for liquid experiment in“SJ10”returns type satellite. The method is especially applicable for unmanned environment as well as non-contact measurement in the experiments.更多还原