AMBROSE'S 
yoldsmith art. It was 
survey of the altar, in 
ermission would not 
analytical restitution 
jected onto the object 
oint projected on the 
ate coordinates were 
JD coordinates, XYZ, 
symmetrically to the 
stitution of the points 
n, both coloured and 
jas, in time, suffered 
unbrose decided, in 
or the Artistic and 
ful to create a precise 
by photogrammetric 
tion with time. Fig. 1 
  
a 1996 
This work was made possible thanks to the collaboration of 
AGIP S.p.A. and of the technicians who provided both the 
highly specialised equipment and operational experience. 
2. PHOTOGRAPHIC EQUIPMENT 
The equipment AGIP made available was: 
(a)Two large-format, wide-angle, universal UMK 10/1318 
Jenoptik-Jena metric camera fitted on an orientation system 
with a Horizontal circle and a device to tilt the 
photogrammetric axis . 
(b) A metric projector developed at AGIP in a study under the 
direction of the author (Baj, 1988) mainly obtained matching a 
UMK camera 10/ 1318 and a projector without lenses. 
(c) A synchroniser, pulse emitter, allowing simultaneous 
photography. 
3. SURVEYING METHODOLOGY 
The photogrammetric survey can be divided into two phases; 
the objective of the first phase is to obtain a dense mesh of 
control points, which could be determined with great accuracy, 
on the sides of the altar. These points, which can be linked to a 
topographic survey for their absolute orientation and for scale 
problem, are not significant in plotting the altar. The second 
phase aimed instead at plotting points inside the mesh in order 
to map the altar and its reliefs. 
3.1 First Phase 
In the first phase, since it was forbidden to place targets onto 
the altar, the methodology by us termed one photogram raster- 
photogrammetry was employed. 
With this method the equivalent of targets on the altar were 
obtained by projecting onto it a mesh of known geometry 
employing the metric projector: 
On the back of the camera-projector, in the principal plane, an 
optical glass on which a mesh and a reference system are 
etched, was positioned so as to ensure that the reference 
system of the mesh and the axes defined by the camera's marks 
coincided. (The etched plate with the reference system will be 
referred to as pseudo-photogram - fig. 2) 
  
  
  
  
  
Figure 2 Pseudo-photogram 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996