Precise building deformation measurement using holographic multipoint replication

For the active control of large-scale structures, especially high-rise buildings and bridges, fast and accurate measurement of local deformations is required. We present a highly accurate and fast vision-based measurement technique and, to the best of our knowledge, first experimental results for the control of an adaptive-structures prototype frame, equipped with hydraulic actuators. Deformations are detected at multiple discrete points, based on a photogrammetric approach with additional holographic spot replication. The replication leads to effective averaging of most error contributions, especially discretization and photon noise. Measurements over a distance of 11.4 m result in a measurement uncertainty of 0.0077 pixel (corresponding to 0.055 mm in object space).