Author(s): Kwonkyu Yu; Woosung Cho
Linked Author(s):
Keywords: Flow velocity; Surface image velocimeter; Image processing; Smartphone; Android
Abstract: The present study aims to develop a real-time SIV (Surface Image Velocimeter) system on a smartphone with Android operating system. Firstly the SIV system figures out the location of the site using the GPS of the phone. Then it measures the angles (azimuth, pitch and roll) of the instrument to calculate the camera distance to the measurement points on the water surface using the built-in clinometer. The only parameter that needs to be entered is the height of the phone from the water surface. After setting the parameters, the camera of the phone takes a series of images. For the normal NTSC type video camera, it captures 30 frames per second. With the help of Java CV, and open source computer vision library, we split the frames of the video and analyzed the image frames to obtain the water surface velocity field. The image processing algorithm was based on a correlation analysis of spatio-temporal images. The code was implemented with Java to the Android operating system. Since all the image processing is performed in the smartphone itself, the SIV system can measure water surface velocity literally in real-time. The test showed that the developed system was greatly effective and convenient. And the measured results showed that the system was fairly useful for river flow measurement work.
Year: 2014