P2-6-2 
Similar, closing of A by B (A B ) is defined as following 
equation. 
A b = (A®B)QB 
(4) 
Figure 1 shows the object A and the structuring element B, and 
figure 2, 3 shows the dilation and erosion of object A by the 
element B. 
+ 
Structuring 
element B 
Object A 
Figure 1 Object A and Structuring element B 
□ 
O 
Figure 2 Dilation 
Figure 3 Erosion 
Figure 4 shows opening results and Figure 5 shows closing 
results. It may be seen from these figures that opening is defined 
as erosion and closing is defined as dilation but the shape of 
the original object is the greatest maintained. Furthermore, the 
remarkable points of this approach are its ability to remove 
small noise. 
Figure 4 Opening 
Figure 5 Closing 
3 EXTRACTION OF THE ATTRIBUTE DATA 
Extraction of the attribute data were performed using 
OC(Opening-Closing) filter. OC filter consist of "opening" and 
"closing". Then, OC filter has ability for both opening and 
closing, and OC filter was defined by following equation. 
I, \ \ 
(A B ) B = flj© B . . .(5) 
Regarding the structural element B, 4 kinds of circle (radius; 3, 
7, 11, 15 pixel) were used. Figure 6 shows the part of historical 
Figure 6 Kawagoe castle town in 1694 
Figure 7 Extracted streets 
Figure 8 Extracted Kawagoe castle area