ciPA 2003 XIX 11 ' International Symposium, 30 September-04 October, 2003, Antalya, Turkey 
These functions are offered, for example, by the ENVI 
software (Environment for Visualizing Images, by Research 
Systems Inc). (Fig. 9). 
Figure 9. Overlap between the original colour image and the 
grey distance matrix 
Once the solid image has been built, the main important 
result is achieved: for each pixel, it is easy to compute in real 
time the XYZ position of the object point in an absolute 
reference system and to display the 3 coordinates on the 
screen (see Fig. 10). 
Figure 10. The solid image and the cursor giving the XYZ 
object co-ordinates of the pointed pixel 
5. SOME APPLICATIONS 
5.1 A coloured 3D model 
One of the possible opportunities offered by the solid image 
is the creation of a 3D model of the represented object. The 
R, G and B radiometric values and the 3D coordinates are in 
fact known for each pixel of the image. When this 
information is known, it is possible, in a very simple way, to 
create a three-dimensional model to which a radiometric 
value corresponds to every object point in the space. The 
mathematical model used for this operation is the central 
perspective model. 
One of the 3D models that is possible to create with the Solid 
image Maker software is a VRML (Virtual Reality Modelling 
Language) model. This 3D model can be visualized with 
specific software for browser web (for example the COSMO 
player or the CORTONA VRML player for Explorer or 
Netscape). 
a) 
b) 
Figure 11. a) The 3D model - b) The 3D RGB coloured 
model - VRML model shown with CORTONA VRML 
player for browser web. 
All these display devices are found free of charge in Internet. 
This type of software has a great drawback: the model can 
only be visualized, but not measured. 
In the case where the metric aspect of the represented object 
is considered to be much more important than its simple 
visualization, using the solid image maker it is possible to 
export the 3D model in some other graphic formats (for 
example DXF and ASCII text file formats). In this case it is 
not possible to associate a radiometric values to each point in 
the space. The model will therefore not be coloured. 
5.2 An artificial stereo pair 
Another product obtainable from the solid image is an 
artificial stereo pair. This couple of images is obtained by 
fixing a taking base that can be chosen by the operator. The 
mathematical model used for this operation is the central 
perspective projection.