FLOW MEASUREMENTS USING VISUALIZED COLOR IMAGES
Department of Computer and Systems Engineering, Faculty of Engineering, Kobe University, Kobe 657, JAPAN
This paper presents some flow measurement systems based on color image information. The first one is a quantitative thermal flow visualization system to obtain simultaneously both velocity and temperature distributions. Flow visualization is accomplished by the use of thermo-sensitive liquid crystal tracers. A correlation method gives the 2-D velocity vector distribution. An algorithm for the color-to-temperature calibration is presented to obtain the temperature distribution.
The second one is a 3-D flow velocity vector measurement system using tracer images visualized by a color spectrum. In this system, tracer particles are visualized by a color spectrum slit method using a prism. The color of a tracer particle can determine its position in one direction. In the other two directions, the tracer particle can be tracked in consecutive frames of the 2-D tracer image by using a correlation and a particle tracking method. A 3-D velocity vector is consequently obtained by a combination of the color spectrum with the methods for 2-D velocity vector measurement.
The last one is another 3-D flow velocity vector measurement system using a spatio-temporal correlation method. The method needs two tracer particle color images observed at a short distance in the flow direction. Each of the images is a time series. The spatial correlation gives 2-D information on a 3-D velocity vector. In addition, the temporal correlation gives information on the third dimension. A 3-D velocity vector is consequently obtained by calculating the spatio-temporal correlation between the two images.