Level Measurement For A Liquid Tank Based On Image Method

Liquid level measurement is much important on many fields, such as production, life, scientific research occasions, and so on. The method of liquid level measurement can be divided into contact measurement and non-contact measurement according to whether contact with the liquid or not.The first method can not adopt those kinds of liquid, such as inflammable, explosive and caustic liquid, which can usually ignite the measuring liquid. With the measuring time increasing, the precision of the contact sensor will be reduced. In order to solve the problem of contact measurement, this paper select the non-contact measurement technology for tanks by using an image technology, which is based on working principle: firstly, a visible laser light beam is brought out to irradiate the tank’s liquid surface at an certain angle, then the beam faculas are formed which includes the information of liquid level; secondly, we use a image sensor to obtain the liquid surface image; finally, we use ARM9 to process the image to obtain the level by using the relation of the incident faculas and liquid level.In this paper, the works are as follows: firstly, the system of a non-contact level measurement has been constructed based on image processing; secondly, research of using one single laser to complete level measurement; thirdly, in order to improve the precision of level measurement, we show a new method, which use three lasers; fourthly, the paper introduces a accuracy level measure algorithm to slove the problem of shaking liquid surface; finally, an ARM9 platform has been used to complete level measurement.The real time dynamic level measure system can measure the level of tank liquid accurately, which can also measure the shaking liquid level.