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International Archives of the Photogrammetry, Remote Sensing
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Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
right stereo-mate left stereo-mate
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interlaced
lenticular image
lenticular imag ;
Figure 2. Interlacing of stereo-mates demonstrated with the
simplest case of two perspective images only.
a; by a; bp
lenticular image
/ S +— lenticular foil
Figure 3, Principle of stereo-viewing using the true-3D
lenticular foil technology.
sn anfnnis in digital and analogue form require an interface to
existing modelling and output systems. The problem of the
optimal matching the cartographic information with relief
Surface is discussed presently in MEX-Group. As far as these
aspects are concerned, initial experiences with AutoCAD and
3D-StudioMAX have been gained. For high-quality hardcopies
algorithms and methods have to be developed and tested which
am at the operational production of high-resolution 3D
visualisations based on lenticular sheets.
The calculation of the single 3D-views was carried out by
means of the software packages SCOP++ and SCOP classic
(TU Vienna) for the image data and 3D Studio MAX for the
vector data and cartographic names. The computation of both
the strip width and the interlacing was accomplished using the
877
commercially available software MAGIC INTERLACER Pro
100, a plug-in for Adobe Photoshop.
4.2 Graphic Modelling
An indispensable requirement for the generation of a
homogeneous image map is the brightening of the shadows and
cast shadows. Due to the fact that most of the shadow areas are
represented by synthetically calculated pixels of the merged
individual image strips, the generation of a shadow mask was
not possible based on a rigid geometric calculation but had to be
materialised by shadow classification. Subsequently, correlation
parameters derived for certain reference areas were used to
compute the "de-shaded" image portions in a way that still the
slightly darkened radiometric features of the respective areas
can be easily observed. Moreover, this enhances the relief
perception, since this “synthetic shadow” serves as a sort of
analytical hill-shading.
5. CARTOGRAPHIC WORK
One big advantage of a true 3D map based on the lenticular foil
technology is, that the whole vector information, i.e. the map
symbols and the lettering, in particular the geographic names,
can be modelled in a way that they are not hiding the actual
surface- (image texture) or relief information (elevation
contours, spot heights) and seem to hover over the terrain, cf.
(Buchroithner, M. F., 2000; Kirschenbauer, S., Buchroithner,
M.T., 1999),
The software used for cartographic work is MACROMEDIA
Freehand and 3D-StudioMAX.
6. CONCLUDING REMARKS
The major advantage of the map products described in this
paper is that they can be viewed in true-3D with unaided eyes.
Apart from frequently applied true-3D visualisations on digital
displays, this hardcopy map has the big advantage that it can be
easily moved and viewed by various persons simultaneously.
This implies that it can also be moved, either as a whole or cut
into partitions which are cloth-bound. The biggest advantage,
however, is that this type of map needs neither a particular
illumination like a hologram nor particular viewing means like
anaglyph (red/green) glasses or similar. The combination of
image data (artificial or natural) shading and - partly hovering -
topographic line information yields an optimum for the map
user. To this end, by combining all the above mentioned assets
the described map type represents a novelty in the cartographic
visualisation of the third dimension which yields tremendous
benefits for all those who until now had serious troubles in
deriving relief information. In this sense, it has an enormous
potential for future applications both in topographic and
thematic cartography.
Today, photogrammetric processing and cartographic work are
supposed to be made completely digitally. As far as the
production of lenticular foil maps is concerned, this is, however,
a rather optimistic point of view. Still, for the generation of a
high-quality graphic output of high-resolution 3D hardcopies
interim steps of visual human quality control have to be
foreseen. However, the transformation of digital 3D models into
appropriate true-3D maps shall be automated as far as possible.
