High Speed Video Measurement Technology And Its Application In Water Tank Level Monitoring

At present,with the rapid development of urbanization in China,high-rise buildings,as an important part of urbanization,are emerging.These high-rise buildings are vulnerable to shaking and even collapse when encountering special disasters such as earthquakes and hurricanes.If collapse occurs,it will have a huge impact on people's lives and properties.Therefore,the earthquake resistance and stability of buildings are very important to the overall safety of buildings,and have attracted widespread attention.In order to further enhance the seismic capacity of high-rise buildings,scholars put forward measures to add damping devices on buildings and have been widely used.TLD(tuned liquid damper)is a very useful passive structure control damping device.Generally speaking,this kind of damper device is to fix the water tank on the top of the building.When the building shakes due to external force,the liquid in the water tank can provide damping effect by the dynamic side force generated in the shaking process.The utility model has the advantages of simple structure,good automatic activation performance,no need of starting device,etc.The dynamic change data of TLD water tank liquid level obtained by monitoring can be used to analyze the disaster level of buildings and evaluate the health of buildings,and can also be used to provide guidance for scientific reinforcement and repair of buildings.Therefore,the research on the dynamic change of liquid level in TLD water tank has gradually become a hot research field.Laser displacement meter is used to monitor the dynamic change of liquid level in TLD water tank,which has disadvantages of single point and one dimension.Close range photogrammetry is a kind of non-contact measurement technology which determines the shape and state change of the target by acquiring and processing the image.It has been continuously innovated and developed in recent decades.High speed video photogrammetry is the latest research achievement of close range photogrammetry.In addition to the traditional non-contact advantages of close range photogrammetry,high-speed video photogrammetry technology also has the capabilities of comprehensive domain,high-speed acquisition,high-efficiency storage,etc.It can obtain the physical and geometric information of the object in a very short time.In this paper,the high-speed video photogrammetry technology is applied to the dynamic monitoring of the liquid level of TLD water tank.The sensor network of the high-speed video Photogrammetry System for the dynamic monitoring of the liquid level of TLD water tank is constructed.The spherical artificial mark points suitable for the dynamic monitoring of the liquid level of TLD water tank are designed,and it is difficult to set up the control system according to the surrounding environment of TLD high-speed video photogrammetry monitoring In the end,the TLD tank liquid displacement field is constructed.It is proved that it is feasible and valuable to apply high-speed video photogrammetry technology to dynamic monitoring of liquid level in TLD water tank.The main research contents and achievements are as follows:(1)In this paper,the development course of close range photogrammetry technology is briefly introduced,the development of high-speed video photogrammetry technology is summarized,the application of high-speed video photogrammetry technology in civil engineering is introduced,and the research status of TLD water tank liquid level monitoring is briefly summarized.The basic principle of constructing high-speed video image sensor network and the characteristics of high-speed video image photogrammetry system are analyzed.This paper systematically studies the characteristics of each part of the high-speed video photogrammetry sensor network,including high-speed camera,data acquisition card,synchronous controller,computer,artificial marker point and lighting source.According to the actual application of this study,a set of high-speed video image sensor network system for TLD liquid level dynamic monitoring is constructed,a spherical mark point suitable for TLD water tank liquid level dynamic monitoring in this study is designed,and the synchronization of the two high-speed cameras applied in this study is verified by stroboscopic method.(2)This paper summarizes the basic principles and methods of high-speed video photogrammetry,including the internal and external orientation elements.In view of the difficulty in arranging control points around the experimental environment,this paper takes the internal and external orientation elements of the image into the matrix as a whole from the perspective of integrated solution,and puts forward the integrated calculation method of internal and external orientation elements.This method first solves the initial value of the similar rotation matrix of the implicit internal and external parameters,then transforms the spatial coordinates into the imaging square coordinates by mapping,then solves the distortion parameters and corrects the image distortion.It avoids the possibility of falling into local extremum and the loss of new precision in the process of solving single element..(3)The high-speed video image sensor network system constructed in this study is applied to the dynamic change monitoring experiment of TLD water tank liquid level.The displacement change of liquid surface target point based on time series in the experiment is calculated and analyzed.The results are compared with the data collected by laser displacement meter in the traditional laser method.It is shown that the displacement change obtained by high-speed video photogrammetry technology is highly similar to that obtained by laser displacement meter,and the error between the vertical displacement and laser method is less than 10%?In addition,according to the experimental results,the appropriate target points are selected to construct the liquid level displacement field.Compared with the traditional laser method,the high-speed video photogrammetry technology has the advantages of the full range monitoring of the liquid level.The liquid level displacement field constructed can more intuitively reflect the change of the liquid level of TLD water tank.The experimental results verify the feasibility of high-speed video photogrammetry technology applied to TLD tank liquid level dynamic monitoring,and provide a new solution for TLD tank liquid level monitoring.