Abstract:
As a remote sensing technique, photogrammetry does not need access to objects being
measured. This can be a great advantage when it comes to deformation monitoring. This
paper proposes a low-cost photogrammetric system for deformation monitoring of
structural materials. The system design is based on a setup consisting of a projector and
multiple cameras, and it is using a pattern projection. The software necessary to perform
the 3D object reconstruction includes modules dealing with epipolar resampling, feature
extraction, matching and tracking, and 3D multiple light ray intersection. The system
was tested by first fitting a point cloud reconstruction of a flat particle board to a
mathematical plane. Then, the same particle board was artificially deformed, and the
normal distances from the new point cloud reconstruction to the original fitted plane
were calculated. The experiment proved that it was possible to detect sub-millimetre
level deflections.