Development of a noncontact liquid level measuring system using image processing

摘要

This paper describes how the authors developed a liquid level measuring system designed to directly analyze images of liquid surfaces. This measuring system is based on the principle that the contour of the image of a slanted metal strip placed in a liquid shows an inflection point on the liquid interface. This liquid level measuring system using image processing is useful in automatically measuring the levels of water, oil, liquefied gases, and alcoholic beverages. Among the features of this measuring system are: (1) it is of the noncontact type, so that there is no need to install a sensor or other high-precision devices close to the liquid to be measured; (2) it can be installed in a way not affected by the liquid; (3) the scale and the liquid surface can be analyzed on an image basis directly, so that periodic recalibration is unnecessary; (4) deviations in measurements can be easily detected by visually checking the monitor screen; (5) images from more than one camera can be processed with a single image processor to reduce total costs. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. [References: 1]