High resolution orthophotos for the recognition of structural damages with “mago”

Abstract

The present work aims to show an innovative method for the orthophoto generation, identified with the acronym MAGO (Adaptive Mesh for Orthophoto Generation) and implemented in C++ environment. The innovations produced by this new approach allow to overcome some problems typically observable in the application of the existing techniques. In particular, MAGO strength points are: (1) the possibility to obtain an orthophoto with the GSD (Ground Sample Distance) resolution, corresponding to the dimension of the pixel of the original image; (2) the creation of a triangular adaptive mesh, generated from the point cloud, able to represent the object of interest surface, which is projected on the orthophoto plan, in a detailed way.
The procedure has been applied to the case study of a masonry road bridge in the district of Genoa, to verify its potential in the study concerning the cracking state of the downstream arch. A portion of the wider crack is reproduced by means of high resolution orthophotos, generated starting from photogrammetric and laser scanner cloud points. Finally, the outputs are analyzed and compared, on the basis of the final metrical quality and the user-friendliness.