A Virtual Simulator for Photogrammetry

This paper shows the use of synthetic images obtained from digital surface models to optimize, on the one hand, photogrammetric planning, and on the other, computer animations. Synthetic images are generated in a photogrammetric simulator built up to project 3D models onto images, after defining a virtual (or real) photogrammetric camera with known inner orientation parameters. The outer orientation parameters are saved whenever a synthetic image is taken. The 3D model is design with simple own format metadata, and is able to recognize 3D solids stored in a library. Each solid is spatially georeferenced and can be combined with any others to generate complex structures. When projecting the 3D model to the set of images, the simulator checks visibility conditions in order to create either distorted or undistorted perspective views. These views are mathematically equivalent to real photographic shots. Besides, the virtual simulator can also be used to optimize before-hand data collection on simple or complex scenarios. Additionally, this virtual simulator for photogrammetry is able to produce free-attitude single or multiple stereo pairs; the latter possibility allows the creation of manual or automatic computer animations. The recreation of image shots is also possible if the inner orientation parameters are changed. Therefore, the performance of each camera for each photogrammetric project can be analysed before starting it.