Image measurement system of bubble characteristic parameters in aerated water flows

Abstract

In order to measure bubble characteristic parameters in the aerated water flows, a new method based on image processing is proposed. Firstly, an image based measurement system is set up. Secondly, segment the captured image and extract bubbles, and then fit the extracted bubbles' area by minimum mean square error (MMSE) with ellipse fitting. Finally, calculate bubble volume by an ellipse fitting with MMSE, and measure bubbles velocities and kinetic locus by tracking and locating them in each frame. A smooth kinetic locus of each bubble is obtained by using cubic spline function to connect the discrete centroid points thus a visual measurement of flow field is guaranteed. The experiment results show that the proposed method both has higher accuracy in stationary and dynamic parameters measurement.