Liquid level detection method and liquid level detection device based on visible laser and image processing

Abstract

The invention discloses a liquid level detection method and a liquid level detection device based on visible laser and image processing. The liquid level detection method comprises the steps of a first step, establishing a measurement coordinate system, wherein the background is the vertical-direction inner wall of a container for storing liquid, a camera and a laser head which is used for transmitting the visible laser are arranged above the liquid level, the camera obliquely faces the background relative to a horizontal surface, an included angle between the optical axis of the camera and the horizontal surface is theta; a second step, obtaining the movement track of a visible laser point through visible laser point movement detection; and a third step, obtaining a corner point coordinate which corresponds with the position of the liquid level based on the image of the movement track, and calculating an actual liquid level value AC'' based on the corner point coordinate according to a formula AC''=AC*sin(<ACC'') / sin(180DEG-theta-<ACC''). The liquid level detection method and the liquid level detection device based on visible laser and image processing have advantages of easy application and high interference resistance.

Description

Technical field [0001] The invention relates to a liquid level detection method and device based on visible laser and image processing. Background technique [0002] Liquid level detection refers to measuring the height of liquid with a certain method. This technology is widely used in many aspects such as daily life, industrial production, oil transportation, power station and energy-saving control of urban sewage motors. [0003] At this stage, water level detection can be roughly divided into contact and non-contact methods. One is the use of a float-type level gauge, which is a mechanical mode and is prone to failure. The second is to use a piezoresistive liquid level transmitter to detect the liquid level. This detection method is designed based on the principle that the pressure somewhere below the liquid surface is proportional to the distance from the liquid surface. At present, most of the products used are imported products, which are expensive and poor in immunity. Th...

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Problems solved by technology

[0006] ① Insufficient anti-interference ability: Due to changes in sunlight brightness and daytime changes, the contrast of the liquid level line is reduced, making it difficult to extract the liquid level line. At the same time, when there are projections of other interfering objects around the environment, it will cause liquid Misdetection of the level line, mistaking the projection of other objects as the liquid level line, thereby detecting errors;

[0007] ②Inconvenient installation: Considering the above factors, it is necessary to avoid direct sunlight and other protruding shelters during installation, and it is necessary to install a white backboard;

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