| Advances in resolution and imaging speed of FPAs (Focal Plane Arrays) have allowed optical measurement techniques to be used in a variety of applications that were previously considered impractical. Here, the uncertainty and resolution of stereo-photogrammetric measurements were investigated for purposes of quantifying complex mechanical deformations. First, a study of the anisotropic, three-dimensional, measurement uncertainties was performed to verify theoretical predictions. Then, a case study of bend-twist coupled wind turbine blade deflections was used to demonstrate a relevant application and methodology of acquiring stereo-photogrammetric measurements. In addition, an image cross-correlation approach was developed for purposes of tracking target deflections for small object displacements or stereo-videogrammetric applications. Results indicate that the uncertainty of stereo-photogrammetric measurements can be readily predicted from system parameters and decoupled into a coordinate system native to the object of interest. |
