Research On Computer Vision Measurement System Of Boiler Drum Water Level

High and low water level accident of industrial boiler drum is one of the major malignant accidents which influence the safety production of the power plant and steel mill for a long time. The main reason is that the measuring technique of water level in steam drum still has some drawbacks. The boiler drum’s water level measuring system belongs to the safety instrument system, which is pointed out in IEC61508and IEC61511safety standards, the operating personnel must monitor the drum’s water level in real time. Power plant and steel mill usually use double color water level indicator in the field, take the picture of the water level indicator by industrial camera and connect it to the industrial television in the control room through coaxial cable. So operators can monitor the water level and find the abnormal level in time, but the industrial television can only realize the function of remote monitoring of water level gauge on the spot, it can not get quantitative values. It is unable to participate in the steam drum water level control system, nor can be achieved with the interactive features of the boiler DCS system.The research of this project is based on the basic condition of industrial field. The system combines embedded technology and computer vision measuring technology, applies the video capture system based on TMS320DM642to acquire the analog video signal of the industrial camera. The video data can be transmitted to the upper computer through the network interface, and the upper computer uses the visual development tool based on LabVIEW to complete the image acquisition and processing. According to the characteristics of the double color level meter in the actual application, this topic proposed the method based on intensity histogram statistics to extract liquid level information after a large number of tests. The whole system can realize the dynamic display of the fuzzy level image and quantization of water level, at the same time, the water-level’s real time data can be saved and be translated into4-20 mA standard current output signal, which can be a proper interface to the DCS system.This paper firstly summarized the domestic and foreign research on development status of the boiler drum’s water level measurement, then put forward the characteristic and significance of using computer vision method to monitor the water level, and the whole system is designed. Hardware part of the system mainly introduced the multimedia microprocessor unit, the video acquisition unit, external data storage unit and network data communication unit, software part of the system mainly introduced the acquisition method of video image and different processing methods of water level image, the characteristics of intensity histogram statistics method and its realization arc deeply analyzed. This article also introduced the video recording, data storage, and the implementation method of current output. Finally the static calibration and systematic test are introduced.