ABSTRACT
To date, the long-term measurement of small displacements in bridges and structures continues to be a first-level technological challenge, especially if it is necessary to have sub-millimeter measurement accuracy. This paper introduces and evaluates a novel displacement sensor for structural monitoring referred to as Laser and Video-based Displacement Transducer (LVBDT), which combines the use of laser beams, light emitting diodes (LEDs), and a digital video camera. The post-processing of video data is based on the principles of virtual visual sensing. While this sensor can capture dynamic displacements, it has been especially designed for static and slow-varying displacements. The laboratory and in-field tests performed demonstrate that the proposed inexpensive solution is accurate, reliable and feasible for a range of applications.
