Displacement monitoring method based on laser projection to eliminate the effect of rotation angle

Abstract

Currently, laser technology has become increasingly mature. Semiconductor lasers have the characteristics of small size, long indication distance, long life, and low cost. Therefore, many studies regard them as the launching devices of monitoring system and fix them at the monitoring points of structures to reflect the displacements of the monitoring points through the spots produced by them. However, this method also exhibits a drawback, that is, this method can only be applied to the case where only displacement is generated at the monitoring point and no rotation angle is generated. If the rotation occurs at the monitoring point, the spot displacement is caused by the coupling effect of the displacement and rotation angle at the monitoring point, which will affect the monitoring results significantly. In this article, a method is proposed to decouple the effect of the displacement and angle and eliminate the influence of the angle sufficiently, by projecting the laser spots onto two screens. This method can significantly improve the application scope of the monitoring system and provide the possibility for its application in practical engineering.

Multi-Point Displacement Synchronous Monitoring Method for Bridges Based on Computer Vision

“…The application results from actual bridges showed that the system could accurately obtain the bridges' dynamic and static displacement information. Liu P et al [11,12] proposed a laser-based horizontal displacement monitoring method for foundation pits. They installed a laser transmitter at the monitoring point, projected the laser spot on the screen, and obtained the horizontal displacement of the monitoring point by shooting the change in the spot's position with the camera.…”

Vibration compensation for railway track displacement monitoring system using biomedical image processing concept

“…In the high‐speed operation of high‐speed trains, a large number of seamless tracks have been used to eliminate rail joints and seams, the seamless track is affected by factors such as temperature, settlement and stress, which will cause relative displacement between the rail and the subgrade, especially in the seamless track, the steel rail cannot be freely expanded and contracted, the temperature force produced by rail temperature changes will cause the rail to move longitudinally, and the excessive temperature force and displacement, will cause the rail to expand or even break, cause the line to lose stability and endanger driving safety [1]. Resonance of railway bridges is a severe concern with high‐speed trains since it affects riding comfort, destroys accompanying structures, and reduces the strength of girder bodies.…”