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Stereophotomap and Stereopace for the management of cultral heritage: An example
The screen is divided into either 2D or 3D independent windows. This allows one to display drawings, images and stereo-models of the object at the same time. In each 3D window a floating mark allow stereoscopic collimations and measurements using a multifunctional mouse. One window contains the Stereophotomap hierarchical data structure, where the user can see the data that the project contains, understand their organisation and then decide how to explore the Stereophotomap.
Figure 2 - Organisation of the screen
A second window contains a "graphic index" In addition, the operator can activate one or more stereoscopic windows simultaneously , that could contain:
- different parts of the land or of the objects;
- different zoom levels of the same area;
- two different stereophotomaps of the same part of the land or the same object;
- link between aerial and terrestrial images.
Figure 3 - Hot-spot joining different blocks and images taken at different dates
This software allows the user to move inside the whole project space. A graphic index gives a general view of the selected partition of the Stereophotomap, the user clicks on a point and the software automatically loads the stereo-pairs of interest, a 3D window appears and the floating mark follows the movements of the mouse.
The movement inside the Stereophotomap is continuous: the user does not see the change of stereo-pairs during the navigation in any direction. When required, the system shows special symbols on the images, highlighting the availability of other strips or blocks. Clicking on the symbol it is possible to load and explore in a continuous way, for example, the Basilica facade, or Giotto' s frescos, or the vaults always referred to the same absolute reference system.
The stereoscopic collimation and the co-ordinate measurements of single points can be carried out by using one of two available procedures. When the operator moves in height, the first procedure moves both images (Helava procedure). The second moves only one image (Inghilleri principle). This last solution is suitable for an unskilled operator: they can monoscopically collimate the chosen point on the fixed image and then eliminate the x-parallaxe by just looking at the homologous point on the other image.
Figure 4 - Co-ordinate recording of the same selected points
In both cases, the system uses matching algorithms, pixel and sub-pixel correlation, in order to refine the collimation and to obtain the required accuracy in measuring X,Y,Z co-ordinates.
The co-ordinates of the selected can be recorded in an electronic sheet (for example Excel).