International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
There is no unique answer after the optimum base length or
better the base-to (object-) distance ratio, because it
depends on the stereo photographer and/or user, to achieve
near natural or super elevated deep perception, see Fig. 3.
For quick applications using normal and wide angle
cameras mainly for 3D documentation purposes, the
empiric baseline to object distance ratio should be
approximately 1:10. It is highly recommended, to take not
only two shots but a queue of stereomates and possibly to
chose different appropriate stereo mate combinations
according to different criteria, but see also SCHUHR,W.
and KANGIESER, E. (2000).
b) Research topics for Arts Aspects of stereoviews:
13. Critical dealing with the Genre 3D photography showing
portraits, Heritage Monuments (see figure 1, 3, 4 and 5)
Architecture, Landscapes (see figure 4 ), Nature, Environment,
Technology etc.. This in particular holds for the "master
pieces", like in figure 3, 4 and 5, but also for available
stereoviews in general, as well as for own stereoviews.
14. Differences in the object choice between 2D and 3D
photography from an artists point of view
IS. (Computer) Generation and/or manipulation of artist
stereoviews
16. The generation of a lost or a so far not existed stereo mate
by analog and/or digital means, for, e.g. Monument
reconstruction purposes and artificial stereomates for paintings
ete.
c) Research topics for Technique Aspects of stereoviews:
17. Optimizing the stereoview gaining procedure
18. Practical criteria for losing the stereo ability
18. The Geometric potential of (available) stereo imagery;
19. A systematic Considering of the effect of the stereoscopic
exaggeration caused by an extremely high base-to-distance ratio
near |
20. Considering the effect of the stereoscopic exaggeration
caused by a combination of stereomates showing different
focus.
Figure 1. Gaining high resolution stereo mates of the historic part of the Jewish cemetery in Magdeburg. To overcome serious
hindrances due to tree crowns, stereo views of the monuments have been taken with a one lens digital Sony Cyber-shot 5.0 Mega-
Pixels camera from a 10 m light telescope staff, using remote zoom, exposure and video control.
Mapping potential of [asterimagery and photos
(for medium scale topograpic mapping of urban areas)
êleteo — —.... (testsite City of Hannover(Germany))
et 1
|
! photo 1:50 000
25m
good 10 mn
i 15 m
medium Ground Pixel Size
Mapping |
Patential |
low |
| 20m
i 40m
L |
bldgs DIMgb; JL.
Int.pr.aid ^ re eget T
a opographic Objects
Figure 2. Stereo ability increases the Heritage site mapping
potential: An original overlapping 1:50 000 synoptically
imagery shows almost the same mapping potential for
topographic objects, in particular for buildings and thus for
Heritage sites, as stereomates(!) with 2.5m until 5m ground
pixel size.
3D Heritage-Imagery as understood here, is part of Geo-
Imagery, in particular when it comes to site monitoring, see
Fig.2.
2. COLLECTIONS OF 3D HERITAGE IMAGERY
Beside their documentary value stereoviews contain important
3D Geometric and Radiometric information
In this context it is liked to remember to the famous historic
German Photogrammetrist Meydenbauer, whose archive is still
maintained as a part of the Conservation Institute of
Brandenburg in Germany. It consists of about 10000 stereo
views on super sized glass, showing important monuments of
Germany. These authentic historic stereoviews in many cases
very successfully have been used for rebuilding and restoration
purposes.
There is no doubt, the most important international Archive for
Heritage stereoviews is the Keystone-Mast collection of the
UCR (University of California Riverside) California Museum
of Photography, holding 350000 (analogue) stereoviews of,
e.g., the famous Keystone Company, of Underwood and
Underwood and of H. C. White etc., from 1892-1963. The
current digitization rate is 10%.
A nearly complete synoptically overview of existing
international Archives holding stereoviews and access to these
data is more than overdue. This task will play an important role
for the RecordDIM task group on Collecting, Compiling and
Sharing Heritage stereoviews. Stretching the question after
Archives for stereoviews, a close cooperation of ICOMOS,
CIPA, the GCI, ISPRS and ISU (the International Stereoscopic
Union) is highly recommended.
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