Comparison between innovative techniques of photogrammetry

Main objective of this work is to suggest some easy procedures to solve typical non-linear problems of analytical photogrammetry, which are also frequent in digital photogrammetry. In particular, we propose a two-steps procedure based on two phases: Relative Orientation and Absolute Orientation, both characterized by non-linear functions. It is firstly necessary to form the model, finding the solution of the Relative Orientation, and then to reconstruct the object considering the solution of the Absolute Orientation. Once validated the technique of orientation of two images, a procedure for the orientation of three images is proposed. In particular, the introduction of a third image allows avoiding human decision to find the final solution. In order to find an easy solution for three-image orientation, each model coming from two images of a triplet is analysed, computing the relative orientation bby using an exhaustive research of preliminary values of its parameters. This non-conventional approach supplies the orientation of two images, taking into account a priori information among four base solutions. Once each model is relatively registered, the absolute orientation is computed by using a linear parameterization. We did a comparison between the method of the three photogrammetric images and a method of Computer Vision