In order to achieve the online surface settlement monitoring of ballastless track,an online surface settlement monitoring system with difference image type has been established, of which the components, the preprocessing measures of images, the precise positioning methods of laser spot have also been researched. The device mainly contains a dot laser and a point-position measurement device that uses a CCD to detect the position change of the laser spot image. Any position change of the dot laser can be measured and the settlement for one point can be obtained remotely. The multi-point settlements can be obtained by using a series of such devices. Some methods such as automatic background sub-tractions and high-precision method for locating the centers of laser spots have been adopted to enhance the stability, adaptability and accuracy of the measurement system. The device has been used in some railway sites and it has the advantages of high accuracy, low-cost and easy installation.
A Remote Subgrade Settlement Monitoring System Based on Optical Method
