Application Study of LED Light Source Image on Water Level Measurement

• Main Authors: Chen, Chan-Jung, 陳家榮
• Other Authors: Yeh, Keh-Chia
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/06836858180574682171

碩士 === 國立交通大學 === 土木工程學系 === 101 === This study aims at the development of water level gauge for flood-prone areas. To overcome common level gauges, expensive cost and not being able to applied to flood-prone areas, this research focuses on five directions: low cost of hardware of the instrument, the availability of internal components, the convenience to set up the instrument, high accuracy of measurement, and the potential of development in the future. Optical triangulation water level gauge is designed in this study. Webcam with low price is used to capture the image in this study. The combination of optical triangulation method and centroid method is applied in the calculation. By tracing the position and the variation of the centroid of light source on the EPS kickboard, water level can be deduced. Experiments of water level are divided into static and dynamic parts. In the experiment of static water level, optical triangulation water level gauge was put in the static sink and measured with two different resolutions; measurements for the two resolutions were compared with the actual water level, and the both error were calculated and compared, too. As for dynamic experiment, flux of water was fixed, and the inaccuracy was measured by putting the optical triangulation water level gauge into sinks with different water levels. The measurements were compared with two submersible pressure sensors and another float sensor. Measurement of the triangulation water level gauge reveals that error range of the static water level is smaller than 0.01ft, which is the standard of precision of measurement set by United States Environmental Protection Agency.