Generation of true ortho-images based on virtual worlds: learning aspects

Abstract

Many of the theoretical concepts in photogrammetry are difficult to understand by means of equations and figures. Furthermore, commercial software is not usually adapted to the requirements of teaching and learning. However, photogrammetric simulation software based on virtual worlds can be used to improve both learning and understanding of complex geometrical issues such as the generation of true ortho-images in urban areas, and assists in training and skills development. This paper tackles image orthorectification by means of a photogrammetric simulation and its generation based on digital elevation/ building/surface models, and the interior and exterior orientation parameters of the image sensor, namely, a digital camera. Internal processes such as masking and visibility analysis which are necessary to yield successful true ortho-images are reported, with examples from both simple and complex urban environments.