Research On Image Monitoring System Of Subgrade Settlement Based On DSP

The smoothness of subgrade surface not only is the key to ensure the safety of railway operation,but also a necessary condition for establishing a modernized railway operation system and an intelligent information management mechanism.The unevenness of subgrade will lead to serious accidents such as train vibration and derailment.At present,the main settlement of measuring subgrade surface includes manual monitoring.However,with the subgrade environment becoming gradually complicated,the adoption of such methods is far from satisfactory in realizing the monitoring of subgrade deformation.Besides,manual monitoring has been unable to meet the requirements of subgrade settlement detection accuracy.The image type on-line monitoring system of subgrade surface settlement can be adopted to acquire the position information before and after monitoring targeted surface settlement through the differential calculation after the center value of the spot is located.In this way,the settlement and deformation of the monitoring point relative to the reference point can be reflected.Based on the overall consideration of both the current situation of railway subgrade settlement monitoring and the application of machine vision measurement in railway field,and meanwhile combining with the characteristics of the field environment and embedded system of subgrade settlement monitoring,it is appropriate to apply the laser and embedded technology to the monitoring of the surface settlement and deformation of railway subgrade.Based on DSP,an image-based on-line monitoring system of subgrade surface settlement is developed.First of all,according to the needs of China's railway operation regulations,it is necessary to collect and investigate on-line monitoring methods and data of subgrade surface settlement regarding long and large tunnels at home and abroad.The comprehensive and systematic integration of high precision spot image center positioning technology and methods and data relevant to target position and attitude correction could be favorable designing the model of image roadbed settlement monitoring system,and determining the appropriate research program.Secondly,according to the research scheme and environmental requirements of the railway site,the design and implementation of the settlement and deformation monitoring terminal are accomplished,mainly including DSP embedded control system,Camera,Laser,Display screen,Inclination sensor,Temperature sensor and Battery selection(applicable to working environment,etc).According to the principle of railway subgrade settlement monitoring,it is required to complete such procedures of image acquisition,data transmission,data storage and its monitoring center.According to the system function,the code work of the corresponding algorithm software is completed.Furthermore,for the traditional spot center positioning technology,the relatively long-distance of the target away from the laser might lead to the occurrence of a big error.The gravity center fitting method is proposed,and its algorithm needs to be transplanted to embedded system for verification.Simultaneously,due to the influence of vibration when the train passes,the deflection between the camera and the target will exert an effect on the accuracy of settlement measurement.In view of this,in order to improve the measurement accuracy of the monitoring system,it is of great significance to introduce a monocular vision algorithm and then transplant it to the settlement monitoring system for further verification.In the end,the purpose of developing the image type subgrade settlement monitoring system in the laboratory lies in achieving the goal of simulating the surface settlement of railway subgrade.The interface of the monitoring center is designed by LabVIEW so as to enable the monitoring center to have a remote real-time control of the settlement monitoring terminal.The accuracy and stability of the system are able to satisfy the requirements of ballastless track settlement measurement,which plays a crucial role in ensuring the safe and stable operation of the railway.