FurtherDevelopments of the Spherical Photogrammetry for Cultural Heritage

The spherical photogrammetry with multi-image panoramas, proved to be very useful for metric documentation and recording of Cultural Heritage. Low cost, easiness, rapidity, completeness are the main advantages of this new technique. As examples of survey Plaza de Armas in Cuzco, Peru, and some Italian churches are shown. The panoramic photogrammetry has been chosen in a public tender to document and survey five villas designed by A.Palladio in Northern Italy. Panoramic imaging is now used to produce interactive exploration and realistic models of some of the most noticeable monuments of Libya in a joint Italian-Libyan project. Recently, to improve the quality of the plotting and capabilities of the technique, some new features have been added: 1) the socalled monoplotting, 2) the imposition of some geometrical constraints such as verticality, horizontality of lines, the belonging to the same plane in the space, 3) the orientation of non-metric plane images by DLT, being the panorama the provider of the control information, and finally 4) the back projection of the panorama for the model rendering and editing, (photomodelling). 1)The monoplotting is the possibility (limited to objects lying on a plane) to plot from one panorama only. The missing stereoscopy doesn’t enable complex details to be plotted, but in case that this detail, lays on a plane, its 3d coordinates are computed by intersection with the plane of the projective lines coming from one panorama. 2) The imposition of some geometrical constraints can help in the orientation phase, providing information useful to improve the accuracy of the plotting. 3) DLT There is the possibility to orient non metric images, as touristic images, or archive images, taking the control points from the panorama bundle block, making use of DLT approach. In particular this is useful where the visibility given by the panorama is difficult, like in the zenithal areas. 4) Photomodelling. The back-projection of the spherical panorama consists in the possibility, given by the knowledge of the orientation parameters, to back project the panorama over the surfaces of the plotted 3d model of the object. This procedure speeds up the rendering phase, making it easier, and partly overcome the difficulty caused by the lack of stereoscopy, to plot rough, uneven surfaces, enabling the interactive photo-modeling. The model can be edited and modified until it coincides with the projections of the panoramas.