image-based displacement monitoring when considering translational and rotational camera motions

A new method to filter the effect of camera motions through background templates is proposed in this manuscript. moreover, the effect of template sizes and brightness on the accuracy of monitored displacement was analyzed and compared. several experiments were performed on a multipurpose testing system (mts) machine using different frequencies and amplitudes to verify the method. all six camera motions (three translations and three rotations) were considered in this study, and the proposed method successfully filtered the effect of these motions. the results showed that filtering the camera vibrations significantly improved the displacement-monitoring accuracy from 53.0 to 97.0%. adopting scale factors for every frame and different position in each frame also helped to improve the accuracy of the monitored displacement from 97.0 to 99.0%. it is impossible to obtain correct nature frequency of the structure before filtering the camera vibrations because there is more than one peak from the camera vibrations or the environment in the fft result. with the developed filtering method, the target motions’ frequencies were successfully identified. © 2021, iran university of science and technology.