Evaluation of OpenCV- and Laser Pointer- based Vertical Displacement Sensor for Structure Health Monitoring

The establishment of automatic observation systems for structural health monitoring of buildings and structures requires the installation of expensive geodetic equipment. The lack of low-cost geodetic sensors limits the implementation of continuous monitoring technologies for early prevention of accidents due to structural integrity failures of engineering structures. Most structural integrity monitoring is carried out manually. The disadvantage of episodic manual monitoring is reduced reaction time in the event of an emergency. The paper presents the results of research on a prototype of a low-cost vertical displacement sensor. This sensor can replace manual levelling in observation systems for geodetic monitoring of foundation settlement of buildings and structures. The possibility of developing such automatic sensors using low- cost uncalibrated cameras, laser modules and an open computer vision library is investigated. The sensitivity of the developed prototype to vertical displacements was 0.12 mm/pixel. This is comparable to the value of the maximum acceptable error for repeated levelling of class I.