Author(s): Seojun Kim; Kwonku Yu; Byungman Yoon; Gabryul Park
Linked Author(s): Byungman Yoon
Keywords: Surface Image Velocimetry; Interrogation area; Particle density
Abstract: SIV (Surface Image Velocimetry), also known as LSPIV (Large Scale Particle Image Velocimetry) is an instrument to measure water surface velocity and to estimate water discharge by using image processing techniques. Since SIV is a non-contacting velocity measurement, it is very convenient and effective, especially economical, compared to traditional water velocity measurement techniques, like propeller velocimetries and the float method. In spite of its great merits, many people seem to think that it is less reliable, compared to the traditional methods. The present study aims to suggest a method to determine the size of standardized interrogation area with specified accuracy through error analyses associated with the various sizes of the interrogation area. For the error analyses, a series of artificial images with various numbers and sizes of particle are used. The analysis results showed that the accuracy of velocity measurements of the image velocimetry was significantly affected by the change of the size of interrogation area. Generally speaking, the error was reduced as the size of interrogation areas became small. For the same sizes of interrogation areas, the larger particle sizes and the larger number of particles resulted smaller errors. Especially, the errors of the image velocimetries were more affected by the number of particles rather than the sizes of them. In the viewpoint of the particle density, the size of interrogation area was small for large particle density cases. For the cases of large number of particle and small particle density, however, the minimum size of interrogation area became smaller.
Year: 2013