Geoscience Reference
In-Depth Information
CELL
1
BLOCK
()
+
CELL
4
BLOCK
()
(5)
Overall
accuracy
BLOCK
()
=
CELL
1
BLOCK
()
+
CELL
2
BLOCK
()
+
CELL
3
BLOCK
()
+
CELL
4
BLOCK
()
After calculating the overall accuracy of each block, total accuracy of the proposed
method was calculated by rationing the sum of diagonals of all blocks to total number
of parcels of all blocks. The performance of the proposed method was evaluated con-
sidering the total accuracy. Figure 3 shows the steps conducted during the study and it
is also a summary of the methodology section.
Figure 3.
Procedures conducted in the methodology.
RESULTS
The original pre- and post-earthquake images are shown in Figures 4a and b and the
FFT images generated from these data are illustrated in Figures 4c and d. As a result
of collapsed buildings and roads, spatial structure and texture of the post-earthquake
image had changed. This caused differences in spatial frequency which can be deter-
mined via Fourier transform. The differences in spatial frequency for pre- and post-
earthquake data can be identified from Figures 4c and d.
