The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
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system [4] . Image registration include relative registration and 
is call for the error control within a single pixel in the high- 
resolution images, or within the pixel size of 10% ~ 20% in the 
low-resolution multispectral image ^ 5 l 
In this study, use the relative registration method, take the 
panchromatic band of ETM + images for the reference image, 
select forty-six control points to make geometric correction 
absolute registration [x! ,the general requirements of registration 
with the multispectral images, in order to reduce loss of 
spectrum by resample, use the nearest neighbour method to 
resample, the accuracy of registration is controlled within 0.3 
pixel, which can meet the need of registrations accuracy. 
ETM+1 
ETM+2 
ETM+3 
ETM+4 
ETM+5 
ETM+7 
ETM+1 
1 
ETM+2 
0.952 
1 
ETM+3 
0.846 
0.927 
1 
ETM+4 
0.626 
0.611 
0.436 
1 
ETM+5 
0.645 
0.719 
0.712 
0.690 
1 
ETM+7 
0.678 
0.780 
0.864 
0.465 
0.891 
1 
Table 1 Correlation coefficient matrix table 
Bands 
combination 
OIF index 
Range order 
Bands 
combination 
OIF index 
Range 
order 
123 
12.832 
1 
134 
22.605 
11 
127 
16.739 
2 
157 
22.724 
12 
124 
17.229 
3 
357 
22.840 
13 
237 
18.043 
4 
245 
23.918 
14 
125 
18.359 
5 
145 
24.316 
15 
137 
19.160 
6 
247 
24.858 
16 
135 
19.693 
7 
147 
25.724 
17 
235 
20.596 
8 
457 
27.442 
18 
257 
21.314 
9 
347 
29.209 
19 
234 
22.169 
10 
345 
29.230 
20 
Table 2. The OIF index of different bands combination (according to the order from small to big) 
3. COMMON FUSION METHODS 
In this study, the fusion methods are all based on pixel-level 
fusion method, pixel-level image fusion method is a process to 
analysis the original information, this fusion method loss the least 
information, so the accuracy of the pixel-level fusion is the 
highest, but the data transmission and processing is the largest. [6] . 
3.1 Fusion Methods 
pixel (tî) show the high frequency information of 
the high-resolution panchromatic image. 
3.1.2 SFIM Fusion Method: The full name of SFIM 
transform is called Smoothing Filter-based Intensity 
Modulation^,which is a brightness transformation based on 
the smoothing filter. The formula of this arithmetic is as 
follows: 
3.1.1 High-pass Filter Fusion Method: High-pass filter fusion 
method a method that make the high frequency components of 
high-resolution panchromatic image superimposed on low- 
resolution multispectral image, to obtain the enhanced spatial 
resolution multispectral image. The formula is as follows: 
»,=SZ 
B.,_ xB 
h 'S^ jk 
i = 1,2,3 
(2) 
F k (i,j) = M k (i,j)+HPH{i,j) 
In the formula, p (ij) is the fusion value of the band k pixel ^, 
the value of multi-special of band k 
In the formula B is the fusion image generated by this 
arithmetic, i is the value of the band, j and k is the value 
of row and line; Ti is the Low-resolution images, here 
denote the multi-spectral band of ETM+; B h is the high- 
resolution images, which is the panchromatic bands of ETM+; 
D 
mean j s simulate low-resolution images, which can be