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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
4. RESULTS 
The edge features are computed based on the first fundamental 
form of the multispectral bands. It is shown in Figure 3 that the 
edge detection results are uninterrupted, and important edges 
have been preserved, but there is much noise in the texture 
region. So the texture marking is required to segmentation. 
The multiscale texture features of each band are calculated from 
the response of log Gabor bank filtering. Each band is filtered 
separately using 2 octave bandwidth log Gabor filter bank over 
6 orientations and 4 frequencies. The wavelength of the highest 
frequency filters is 3 pixels. The scaling between successive 
filters is 2. Thus, 4 scale texture features are produced for each 
band. Then, the texture features of all bands are fused in scales 
based on first fundamental form. 
Figure 3. Edge features of multispectral bands 
Figure 4. Texture marker in scale 2 
For obtaining marker image for watershed segmentation, the 
texture features are segmented using the moving threshold 
algorithm, in which 50 pixels is used as the minimum region 
size. Figure 4 shows the texture marker in scale 2, in which the 
texture regions are marked distinctly. 
Then, edge features are segmented based on texture-marked 
watershed transform, which produce 4 scale segmentation 
results. The segmentation result marking with texture features 
in scale 2 is plotted in Figure 5. There are 104 regions in the 
result. It is shown that the region boundaries are congruent with 
most landscape objects. With the texture marking, the over 
segmentation problem is solved so that the count of segments is 
decreased to a meaningful number. But it is also can be seen 
that there are some over-segmentation in severe texture areas 
and under-segmentation between different colour areas. 
Figure 5. Segmentation result in scale 2 
RS (%) 
Figure 6. Segmentation accuracy in different scales 
A reference map, as shown overlaid in Figure 1, is produced for 
quantitatively assess the segmentation accuracy in appropriate 
scale. The count of reference polygons is 48. The RC and RS of 
the segmentation results marking with different scale texture 
features is shown in Figure 6. Scale 1 is corresponding to the 
highest-frequency texture features, whereas scale 4 refers to the 
lowest ones. It can be seen that the region count parameter RC 
is increased with the texture marking from low frequency to 
high. That is, the segmentation will become more fragmental if