Real Time Instrumentation of Unsteady Flow Phenomena based upon Color Image Information

本研究的初衷是为了提高流速测量的准确性，利用彩色图像信息，同时利用莫尔法获得势场和示踪法获得速度矢量场。然而，在后一个目的上，事实证明，同时测量上述两个量的可视化方法在技术上是困难的。因此，我们把注意力转向温度场和流场共存的自由对流。通过使用液晶示踪剂使两个场可视化。从可视化的彩色图像中，完成了速度矢量和温度分布的同时测量。在此基础上，研制了三维流场速度矢量分布图像处理测试系统，具体验证了以下结果。1)建立了相关法速度矢量分布图像处理测试系统。实践证明，该系统对非定常流场也是十分有用的。2）通过图像的分色处理，同时获得了三维水流不同水深处的速度矢量分布; 3）将该系统应用于热分层的动力学行为，获得了温度和速度矢量随时间的变化。然而，在这种彩色图像处理仪器系统中，颜色测量的空间分辨率仍然较低。因此，发展一种广泛应用的分色算法，研究温度与颜色之间的严格关系，是今后需要解决的问题。

The original purposes of this study were to improve the accuracy of flow velocity measurement and to obtain a potential field by Moire method and a velocity vector field by a tracer method at the same time by using color image information. On the latter purpose, however, it was turned out that the visualization method for measuring the above two quantities at the same time was technically difficult on investigation. Therefore, we directed our attention to a free convection in which the temperature and flow fields coexist. The two fields were visualized by using the liquid crystal tracer. From the visualized color images, simultaneous measurements of the velocity vector and temperature distributions were completed. Furthermore, the image processing instrumentation system of velocity vector distributions in three dimensional flow fields was developed.Consequently, the following results were specifically confirmed. 1) The image processing instrumentation system of velocity vector distributions by using correlation method was established. It was proved that this system was very useful for even an unsteady flow field. And, the algorism for correcting erroneous velocity vectors was developed.2) The velocity vector distributions in different water depths of a three dimensional flow were simultaneously obtained by the color separation of the image.3) The changes of temperature and velocity vector distributions with time were obtained by applying the system to the dynamic behavior of a thermal stratification. In this color image processing instrumentation system, however, the spatial resolution of color measurement is still lower. Therefore, the problem remains that to be solved in the future is to develop an extensively used color separation algorism and study the strict relation between the temperature and the color.