Figure 7 Orthoimage and unwrapped image.
The RMS differences of similarity transformation between
mosaic and control points in XoYD object space were 2.8
pixel (= 1.4 cm) in the direction of development and 0.9
pixel (= 0.5 cm) in height.
6. CONCLUSION
An approach has been formulated for mapping 3D objects
of regular shape, to which it is possible to fit mathematical
REFERENCES
Chandler, J.H., Cooper, M.A.R., 1991. Determining cylin-
drical parameters — an alternative approach. Land and
Hydrographic Survey, September, pp. 5-7.
Feltham, R.M., 1990. Determining cylindrical parameters.
The Photogrammetric Record, 13(75), pp. 407-414.
Fotiou, A., Livieratos, E., Lombardini, G., Paraschakis, l.,
1991. Dome representation using photogrametric data
and best fitting techniques. ISPRS Journal of
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Karras, G.E., Patias, P., Petsa, E., 1993. Experience with
rectification of non-metric digital images when ground
control is not available. Proc. XV International CIPA Sym-
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Patias, P., 1991. Architectural photogrammetry goes to
the digital darkroom. XIV CIPA Symposium, Delphi, pp.
Figure 8 Full mosaic of the digitally unwrapped images
surfaces, from single images. In case the solid is
developable, it has been demonstrated that besides
vector data one may also perform digital 'unwrapping' and
mosaicking of the original images.
Here, the right circular cylinder has been investigated and
tested in practice. It was seen that the accuracy of object
space coordinates depends essentially on the angle
under which projective rays meet the surface. Mapping
limits for each image should be fixed accordingly; control
has to be reliable and well distributed.
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ones. It is believed, however, that the less demanding is a
method in its use the more it may encourage users to re-
cognize the merits of digital close-range photogrammetry.
In this context, the presented method is being introduced
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1993, to function also with vanishing points rather than
control points). This contribution represents a further step
towards fully exhausting the potential of monoscopic and
monoplotting techniques for the purposes of architectural
and archaeological documentation.
129-139.
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294
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
KEYWOI
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