map used in this paper, and the historical map is around the
Kawagoe castle, Saitama in 1694. Figure 7 shows the extracted
streets area, and figure 8 shows the extracted Kawagoe castle.
Then, subtracting the streets and the castle area from figure 6,
image which consist of dwelling house, shrine area, boundary
lines and characters are obtained, and this result is shown in
figure9. Figure 6 doesn't include the shrines, but the shrines
were extracted by the same procedure.
However, basic OC filter has not ability to extract the characters
and boundary lines in figure 9 because of their width is too
narrow (1~5 pixel) . In order to extract these characters and
lines, opening procedure were transformed as follows
[NAEMURA, 1997].
1) Butterfly-shape that is formed by the two lines intersect with
30 degree at the sample point is set as the structuring element.
2) The structuring element rotate every 30 degree at the point.
3) Line within the butterfly area is extracted using linearity and
continuity.
Figure 10 shows the concept of this transformation opening,
and the extracted lines are shown in figure 11.
Figure 11 Extracted boundary lines
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^ 10 pixel w
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V * <f,
te* - ™ I
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Figure 12 Extracted characters
Figure 10 Transformation opening
Here, subtracting the lines from figure 9, the characters can be
extracted as a black color parts in the figure 9. Figure 12 shows
the extracted characters and figure 13 shows dwelling house
area subtracting the lines and characters from figure9.
3.1 Classification of Dwelling House Area
Figure 13 still includes samurai residents, townsman house. In
order to classify these area, historical map in 1790 was used,
and the samurai residents and townsman house area were
extracted respectively using OC filter. These extracted area are
shown in figure 14 and figure 15.
3.2 Remapping
Due to insufficient precision instrument or according to each
author's subjective point of view, the historical maps were
generally drawn with unequal scale. In other words, there are
many different distortions in historical maps.
§R«ii Mi
