Large Range Liquid Level Real Time Measuring System

In consideration of tide measuring instrument whose characteristic are large measuring scale, high accuracy and faster measuring speed ,we design a set of height measuring system based on digital image process theory. The system mainly includes vision measurement part, tracking control part and tidal simulation part three components. The experimental results show that this system has superior performance over the measurement of large scale water level with good robustness and it could complete a measurement with high accuracy.The main research contents include:1. Analysis the current situation of the measuring method of liquid level at home and abroad, elaborating the research background and significance of the large range liquid level real time measuring system designed in this topic.2. Complete the large range liquid level real time measuring system designing, through processing the image of ruler and water tube captured from CCD camera to complete the task of high accuracy measurement. The technical indicators of this system are 0 ~ 8m measuring range, 0.1mm measurement resolution and±1mm measurement precision.3. Write the communication program getting the measuring result of the environment sensors including temperature-humidity sensor and atmospheric pressure sensor, so we can monitor the change of the experiment environment.4. Design the visual detection part of this measuring system and complete the 3 pattern recognition tasks including the identification of ruler scribed line and the identification of the liquid level position. During the recognition of ruler number, we use template matching method with respect to the robustness of algorithm and stability of the measuring system. As to the identification of ruler scribed line, we make full use of the gray features of the image and structure characteristics of the ruler. We use the edge detection operator to identify the position of liquid level.5. In order to realize the real-time measurement of the height of liquid level, we design the automatic tracking system though the feedback control of the position of the motor according to the real-time position of liquid height.6.Design the tidal simulation system to control the inlet valve and outlet valve automatically, which make the speed of liquid can be set as any numerical value between 0.3mm / S ~ 2.0mm / S and write program to realize the sinusoidal variation of the liquid level, completing the simulation of the tidal phenomenon.