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7. Summary and problems to be solved in the future
The Personal Digital Photometric System
"PyramidStereon" developed by us isa simple sys-
tem activated only by the personal computer and
its peripheral devices. As is evident from the
compilation of DTM in comparison with conven-
tional method, we could drastically reduce the
processing time, and in terms of measuring ac-
curacy, we were successful in minimizing the
mis-matching by employing semi-automatic method,
namely the visual confirmation. Based on these
findings, we consider that this system can be
put to the practical use at the fieldswhere
prompt and efficient acquisition of DTM is
necessitated. Especially, the use of GIS is ad-
vocated in recent years, and therefore, the
demand for DTM is considered to increase as the
important basic information.
As for the practical use of this system, we con-
sider it to be important to discuss this system
from the following viewpoints.
(1) The system to supplement stereo plotter
From the viewpoint to supplement the conven-
tional method of map construction, this system
shall be positioned as the system to efficient-
ly compile the DTM which is regarded important
as the basic information for GIS in recent
years. Also, if the digital orthoimage is recog-
nized more highly as a map, this system will be
regarded as a new function that stereo plotters
do not have.
(2) Application of ground survey
Although photogrammetric principles and methods
have already been used for the ground Survey,
there is a problem in orientation works, etc.
because the main subjects of stereo plotter are
aerial photographs. If the functions necessary
for ground survey are added to the orientation
processing function of this system, this system
Will exhibit the higher simplicity in use and
be used in various fields of survey.
(3) Application to the construction of image
database and topography database of CAD & CG
As an application of structure design and scen-
ic analysis, this system can be used for the
construction of each kind of database of CAD
and CG. In this case, the accuracy and efficien-
Cy of data acquisition can be adjusted freely
according to the use purpose of database be-
cause aerial photographs or ground photographs
may be selected as necessary as the input media.
Currently, we are continuously attempting to im-
prove the system, taking up the following mat
ters as the main issues.
* To clearly identify the unmatching points
and skeptical portions (-->improvement of
efficiency of visual confirmation)
* To identify the kinds of land use from the
correlation property (-->improvement of
measuring accuracy)
* Reinforcement and replenishment of orienta-
tion function (-->application to other than
the aerial photographs)
* Compatibility with the digital mapping tech-
nologies (-->application to map drawing)
We will add discussions to the system from
various viewpoints in the future, too.
(References ]
1) Konecny, G. , D.Pape: Correlation Techniques
and Devices, pp. 323-333, Vol.47, No. 3, Photo-
grammetric Engineering & Remote Sens. , 1981. 5
2) Hattori,S., Mori, C. : Outlook on Methods of
Stereo Matching by Computer and Auto-correlat-
ors for Photogrammetry, pp. 17-76, Vol. 25, No. 1,
Journal of the Japan Society of Photogrammetry
and Remote Sensing, 1986
3) llelava, U. V. : State of the Art in Digital
Photogrammet ric Workstations, pp. 65-76: Vol. 19,
No. 2, The Photogram. Journal of Finland, 1991
4) Li,M. : Hierarchical Multipoint Matching, pp.
1039-1047, Vol.57, No.8, PE & RS, Aug. 1991
5) Ackermann, F., M. Hahn: Image Pyramids for
Digital Photogrammetry, pp. 43-58, ISPRS Con-
ference on Digital Photogrammetric Systems
Munich, Sept. 1991
6) Thorpe, J. : Aerial Photogrammetry: State of
the Industry in the US, pp. 1599-1608, Vol.59
No. 11, PE&RS, Nov. 1993
7) Oyama, Y. : Semi-Automatic DTM Generation from
Stereo Aerial Images, pp. 45-52, Proceedings of
Applied Survey Technology, Japan Association
of Surveyor, June. 1995
8) Oyama, Y., Ohsawa, Y., Masaharu, H., Ishida, K..
Sato, I. : Semi-Automatic Recognition of Land
Use Change from DTM by Aerial Photographs,
pp. 1-6, Proceedings of 6th Symposium of Func-
tional Pattern Information, Apr. 1995
293
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996
