Abstract:Based on the computer vision theorem, this study uses off the shelf cameras to measure structural dynamic displacement by the technique of camera coefficients calibration, image point tracking, and three dimensional point reconstruction. To validate the proposed technique, the tests of sinusoidal motion of a point, free vibration of a cantilever beam, and a three story building model under earthquake excitation, are performed. Results show that the proposed technique has the capability of accurate displacement measurement and the wide future of engineering application, which is shown to be a good complement to the traditional sensors with the advantages of 3D and multi point measurement, non contact type, more flexibility, and low cost.