When the vanishing point is not at infinity one must 
extend the procedure by defining or the position of the 
principle point (obviously approximately, by digitizing the 
four edges of the image), or the ratio between a horizontal 
and a vertical linear elements, or finally, by providing a 
given angle between two distinct lines in the image. After 
having activated the conclusive procedure, in a few 
seconds the rectified image appears on the screen. 
The four images used have been rectified without 
absolutely taking into account of the fact that they had 
been taken with a metric camera. 
The rectifications have then been assembled in a mosaic 
in order to obtain the perspective view, which is partially 
shown in figure 6. The final file has a size of about 12 Mb. 
The final image has then been scaled using the given 
distance between two of the 19 control points. As a metric 
test one has checked the residuals on the other points 
after the operation: these resulted sometimes to be larger 
than 10 cm. This result is, as forseen, not very significant, 
regarding the precision. 
With the mosaic of rectified images a number of test have 
been carried out with respect to the possibilities of vector 
editing and editing of the image itself by changing 
intensities, the cutting of an image along lines and the 
improvement of the areas of overlap between the images. 
    
Figure 6 - The rectifications assembled in a mosaic with program Archis. 
3.4 Conclusions 
The result does not have the metric characteristics of even 
semplified photogrammetric procedures. It can however 
be useful for a series of operations, which often lead to the 
necessity to carry out a survey of a view. In our opinion it 
is certainly better to have a product like that obtained with 
Archis than that, which one often obtains from an 
inorganic composition of direct measurements, 
photographs and representations on the spot. 
It is a very important fact that the final result contains all 
information of the photograph and is not a summary of 
only few lines. Processing of vector data can still and 
always take place. 
An other fundamentally large potential consists of the fact 
that the use is required of normal amateur cameras. 
Besides, control points are not required; for the scaling of 
the rectified image is is sufficient to know a few distances 
between points. 
The defects of a software like Archis are in the simplicity 
of its use. If the determination of the vanishing point is not 
carried out correctly, one risks to distort significantly the 
quality of the results from the geometric point of view. 
The approximations are quite allowed when the object is 
plane. All deviations from planarity of the surveyed wall 
are translated in ever worse approximations with respect 
to reality. 
References 
Bezoari G., Guzzetti F., 1992. L'impianto generale di un 
rilievo. Recuperare. 2/92. Milano. 
Guzzetti F., Monti C., 1988. Esperienze fotogrammetriche 
con l'apparato Rollei. Bolletttino della SIFET n.2 Roma. 
Colombo L., 1991. Prospettive della cartografia 
fotogrammetrica e digitale. Pixel, n.5/91. 
Astori B, De  Vincentis F., 1992. Metodologie 
rappresentative di un complesso architettonico: aspetti 
teorici ed operativi. La Rivista del Catasto e dei Servizi 
Tecnici Erariali. Roma. 
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