Abstract
The displacement measurement approach by high resolution / high speed video camera and image processing have the possibility to realize simple and detailed railway bridge deflection measurement without target. However, its measurement accuracy has not been verified in detail so far. This study verified the accuracy of multiple points measurement of non-target video measurement method for micro displacement through experimental tests of model bridge. As a result, it was clarified that displacement of approximately 0.03 pixel (full amplitude) can be measured excepting for the white spot. In addition, the applicability to practical were estimated based on the past actual measurement results and experimental results. As a result, it was suggested that deflection measurement will be possible up to a measurement distance of 50 m if the bridge has over 20 m span and it is not at night. Finally, by a field test was conducted and the results indicated that the non-target optical method is possible to measure the deflection to the train passing with approximately same accuracy as the optical one with target and U Doppler I.
