Kang, Joon-Mook
So as to extract precise vector data by applying the film-based photogrammetry to be based on film about the object
that scale is big and treatment is difficult like the bell, image acquisition to be based on exact photography plan is
important.
This research was acquired image by deciding the photography method to consider depth and interpretation range, so
that improper time differential may not be generated at the part that undulations are serious and form is complex like as
yongnew. In this study, this research was acquired image by changing f-stop and shutter speed about model into 8-22
and 1/60-1/8. Table 1 is what showed the minute photography plan for precise pattern analysis.
1.3 ESTABILSHMENT OF COORDINATES SYSTEM AND MEASUREMENT OF DATUM POINT
For the geometrical form analysis of precise digital data and the framing of digital drawing about the bell of Sungduk
the Great, this research was measured and constituted same coordinate system about the inside and outside surface of
the bell. And, for preventing the tremor of object, this research was fixed 4 directions with strong wire of which
thickness is 5 X This research was established the right-angled coordinates system to lay the origin(0,0,0) of
coordinates system at the south of temple bell make the East of -X side, the North of +Y side, and height direction of Z
axis.
So as to execute the section analysis about 4 directions inside and outside the bell, this research was attached the belt-
target for doing the section analysis perpendicularly on the surface of South-North direction, East-Western direction,
South-Eastern and North-Western direction, and South-Western and North-Eastern direction inside the bell, and
acquired 3 dimensional coordinates result of same coordinates system. Besides this research was acquired the result of
datum point of same coordinates system by arranging the datum points by 6 points per the model for image
interpretation and arranging 140 points or so about total 28 models.
2 ESTABLISHMENT OF DIGITAL DATA
This research was established 3 dimensional digital data about the bell after passing through the transform course for
establishing all the elements in stereoscopy with the digital data of vector form by reproducing the geometrical
condition to be same as the time of image acquisition. This research was used 3D Bursa-Walf transform method of
MSPM(MGE Projection Manager) so as to locate the result drawn by each photo model on same coordinates system.
This research was constituted each model with the vector component of point and line and stored it with DGN pile to
be MicroStation file. About each pattern located at same coordinate, this research was established the data base for the
geometrical image analysis of the bell by creating 3D model (TIN) through using MSM (MGE Terrain Modeler).
Figure 3 is showing the original image, digitizing result and modeling result acquired about beechonsang to be the
representative pattern of the bell.
@ ©
Figure 3. Show image of the Beechonsang : (a) original Image (b) Digitizing result (c) Modeling Result
3 NALYSIS OF DIGITAL DATA
31 ANALYSIS OF AREA AND VOLUME
This research could obtain the area on XY plane by transforming 3D digital data into 2D and calculated volume by
establishing DEM about the inside and outside of the bell. In the next Table 2 showed the numerical value to be more
or less, the volume of North-Eastern direction and South-Western direction is greater than the volume of North-Western
424 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000.