True Digital Orthophoto of the San Marco Basilica in Venice

The orthophoto is a powerful instrument of representation which combines radiometric and geometric properties. In architectural applications the orthophoto production cannot be performed by using the traditional orthophoto approach. True digital orthophoto is a new technique which uses several images and a complete DEM of the object in order to produce an orthogonal projection of complex objects. All the radiometric information hidden by central perspective in one image must be recovered by other images and the orthophoto production must choose, the best image to be used, one by one. Complete shape description can be easily achieved by using modern terrestrial laser scanner devices. The paper shows the true digital orthophoto production of the central door of the San Marco Basilica in Venice: the result obtained is a complete radiometric and geometric description of the studied object under examination.