Author(s): Il Won Seo, Donghae Baek
Linked Author(s): Donghae Baek
Keywords: Pollutant mixing, tracer test, fluorescent dye, UAV, concentration fields
Abstract: The tracer test using fluorescent dye has been generally performed to understand the mixing behavior of pollutants accidently spilled into river. However the existing tracer test method requires a considerable amount of cost and labor, and it provides only concentration distribution in time at the fixed location of fluorometers. In this study, we developed the image processing techniques on the aerial images taken by digital camera which is mounted on the unmanned aerial vehicle (UAV) during performing the tracer test to overcome the limitation of conventional tracer test. The tracer tests were performed in the meandering channel which was artificially constructed but on large scale. The 20% of rhodamine WT was used as the tracer material. For acquisition of the aerial imageries, DJI-Phantom3 professional, which is the inexpensive and commercial UAV, was used, and the images were taken by the normal digital camera, which has three optical bands. The images were sequentially taken as 4K resolution (3840 2160) and 30 frames per second during tracer test. The image data were converted to concentration data in all time applying the image processing technique. It showed the determination coefficient over 0. 9 with the concentration data measured by fluorometers in water channel. The spatial distribution of concentration well represented represents well the effect of advection and dispersion in meandering channel, especially the transient storage in vegetated area. It is expected that this experimental method can contribute to the spatial analysis of dye dispersion in open channel flow, and facilitates to reduce the cost and labor for tracer test
Year: 2017