ibul 2004 
e is the 
ssed by 
to the 
sensitive 
1. So the 
as: 
lgorithm 
structure 
duced by 
peration. 
a lighter 
| is taken 
| belongs 
in a 
he same 
between 
to soften 
iting (11) 
where o is a threshold value. 
3. Results and discussion 
In this paper the IKONOS image in Shenzhen of China with the 
spatial resolution of 4*4 (Fig.1) was selected. The objects in the 
image are labeled with different morphology features which are 
the sizes of the structure elements. The image was segmented 
and coded at the same time according to morphology feature. 
The proposed segmentation algorithm was implemented by 
VC++ programming. The primary objects in an image include 
buildings, streets, green belts, rivers and ponds. 
In this method, the selection of structure elements is very 
important. The structure elements with different shapes and 
sizes should generate different results. The result obtained by 
octagonal structure elements is better than that by square 
structure elements which have been proved by experiments by 
others. In this paper, a structure element sequence formed by 
two octagonal structure elements denoted as N, and N,, 
where 
N, = N, © N, (13) 
The diameters of the two structure elements are 7 and 13 
pixels and O is 5. Five resultant images could be obtained after 
  
Fig.1 IKONOS image in Shenzhen, China 
49 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004 
segmentation (figures 2-6), and the black part includes pixels 
with same morphological features. Figs. 2 and 3 show the peaks 
with different features. In Fig.2, the light objects smaller 
than N, mainly consist of buildings, while the light objects 
g.3. Some 
greater than. N, but smaller than N, appear in Fig 
pixels belonging to plains, which have a lower response to the 
structure elements in a given size, can be found in Fig.4. The 
objects included in Fig.4 are related to the selection of threshold 
value G , a greater 0 means more objects will fall into this 
image. As rivers and ponds are homogeneous in a large area that 
are bigger than the structure elements in given sizes, they have a 
lower response to the structure elements. In general, if the size 
of the given structure element is great enough (larger than these 
objects), the objects will belong to valley images because these 
objects are very dark (local minimum) in the image. Figs. 5 & 6 
consist of valleys with different morphological features. Some 
small and dark objects are mainly included in Fig.5, such as 
grass plots and shadows between buildings and some streets 
within residential areas. Grass land and greenbelts located on 
both sides of roads in bigger areas are shown in Fig. 6. 
  
     
     
   
    
     
   
      
    
  
  
     
  
    
        
i te 
QU Du RY 
UE AS vai 
I dea SEA 
Fig.2 Light objects sensible to structure element N, 
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