International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
datasets seem to be only images that does not have a vector
model. (Schermann, 2001)
Basu et al. report a Java3D application using foveation: “The
method combines foveating JPEG texture files with LOD
representation in JAVA3D”. In their work, although there is a
vector wire frame on which the textures are mapped, the focus
of foveation is on the texture mapping and not on the whole of
the model. (Basu et.al. 2002)
[n an earlier application, in 1993, Funkhouser had created a 3D
architectural walkthrough model without photo-textures. He had
re-created the model in several other resolutions, pre-computed
the visibility information for each cell that he created under a
spatial subdivision: all into a database system. It is a successful
(though laborious) work in terms of "foveation" idea, which
was called “visibility determination” in this work. (Funkhouser,
1993)
5. CONCLUSIONS & FUTURE WORK
Foveation is not utilized in photogrammetric visualizations as
far as the author is aware. It certainly is interesting for all kinds
of photogrammetric applications. Both in 2D and 3D
visualizations, particularly on large screens (e.g. panoramic
screens), when visualizing big aerial or satellite images, digital
photogrammetric applications would benefit from such a
reconstruction.
In a virtual environment, it would be ideal to have a
photorealistic 3D world where foveation was possible and
smoothly working based on a wireless eye-tracking system.
VEs will eventually develop into fully perceptually modulated
“places”, also processing other human senses. Until then,
testing the possibilities of foveation for web-based VR could
make the interactive models accessible to an even wider
audience.
The current methods such as mesh simplification, visibility
culling, view frustum and view dependent rendering makes the
high quality 3D graphics usable. Foveation is as useful as the
listed methods.
No examples of stereo imaging systems were found utilizing
foveation. The ongoing work for the author of this paper is to
implement and test the performance of foveation for stereo
imaging, in particular for anaglyph images, because viewing
anaglyph does not require complex hardware acquisition and it
can be published on the web.
References
Chang, E., 1998. Foveation Techniques and Scheduling Issues
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Chang, E., Yap C., 1997. A Wavelet Approach to Foveating
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Clark, J. H., 1976. Hierarchical geometric models for visible
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Basu, A., Cheng, L, Pan, Y., 2002. Foveated Online 3D
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Funkhouser, T.A., 1993. Database and Display Algorithms for
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Ware, C., Interactive Data Visualization Course Notes.
URL: http://www.ccom.unh.edu/vislab/VisCourse/VR.html.
Page visited on 26.11.2003.
UTEXAS 2002, Center for Perceptual Systems, The University
of Texas at Austin
URL: http://fi.cvis.psy.utexas.edu/foveated_questions.htm#Q3.
Page visited on 26.11.2003.
Acknowledgements
The author would like to acknowledge the financial support
from Finnish Cultural Foundation.
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