1179 
THE FUSION OF SPOT PANCHROMATIC AND TM MULITSPECTRAL 
IMAGE BASED ON MULTI-BAND BIORTHOGONAL WAVELET 
LIANG Shouzhen 3 ’ b ’ 1 *, LI Lanyong 3 
3 School of Geomatics, Liaoning Technical university , Fuxin - Lilanyong@sohu.com 1 
b Yantai Institute of Coastal Zone Research for Sustainable Development, Yantai - Liangshzh0816@163.com 
Comission VII,WG VII/6 
KEY WORDS: Fusion, Multi-band,Biorthogonal,Wavelet,TM,SPOT 
ABSTRACT: 
Remote sensing image fusion aims at integrating the information conveyed by data acquired with different spatial and spectral 
resolution from satellite and aerial platforms. Image fusion is a very important issue in remote sensing and mapping applications 
such as features extraction, image classification because the fused image can provide more comprehensive information than single 
image. At present there are various methods developed to fuse or merge images from different sources, acquired at different time or 
having different characteristics, particularly low-resolution multi-spectral and high-resolution panchromatic images. Some fusion 
techniques or methods, such as PCAfprinciple component analysis), IHS (Intensity-Hue-Saturation) and Brovey transform ,can 
provide superior visual high resolution multi-spectral images but ignore the requirement of high quality synthesis of spectral 
information .In other words, there are some distortion of spectral characteristics in comparison with original multi-spectral 
images.This paper develop a nesw method which integrate multi-band wavelet and biorthogonal wavelt to merge remote sensing 
images. Multi-band wavelet transform can deal with arbitrary integer ratio of images resolution, while biorthogonal wavelet 
transform can reduce the ambiguity on the edge of image because it is symmetric and smooth. A example of fusion based on three- 
band and biorthogonal wavelet transform is experimented with SPOT panchromatic image and Landsat TM image and the fused 
image is compared with fused images based on orthogonal wavelet ,PCA,HIS and Brovey transform respectively in this paper. Some 
parameters including mean gradient, combination entropy, standard deviation and correlation coefficient are adopted to appraise the 
fused images. 
1. INTRUDUCTION 
Image fusion refers to a process that extracts redundant and 
complementary information from a set of input images and 
fuses it into a single and more complete image. The fused 
image should have more useful information content. The fusion 
of the two images can take place at the signal, pixel, or feature 
level. Presently many image fusion methods have been 
proposed for combining remote sensing data .A detailed review 
on this issue was given by Pohl and Van Genderen (Pohl et 
al, 1998).The well-known methods are, for example, the HIS 
(Intensity, Hue, Saturation) (Edwards et al, 1994), PCA 
(Principal components Analysis) (Zhou, 1998; Chavez, 1989), 
Brovey Transform (Gillespie et al, 1987) .These methods are 
conventional methods which have been studied widely. But 
these fusion methods have some deficiencies. At least in 
comparison with the ideal output of the fusion,these fusion 
techniques can often produce poor results.The most obvious 
problem is that it leads to some distortion of spectral 
characteristics. Recently developments in wavelet analysis 
provide a potential solution to these drawbacks. For example, 
Nunez developed an approach to fuse a high-resolution 
panchromatic image with a low-resolution multi-spectral image 
based on wavelet decomposition (Nunez et al, 1999). Ranchin 
and Wald designed the ARSIS concept for fusing high spatial 
and spectral resolution images based on the multi-resolution 
analysis of two-band wavelet transformation (Ranchin et 
al,2000). 
However, the fusion method based on well-known two-band 
wavelet, which have been successful for the fusion of SPOT 
panchromatic and other multispectral images, is not very 
efficient for the fusion of images whose ratio of spatial 
resolutions is not 2 n (n = 1, 2, 3, ...), e.g., for fusing a 10-m 
resolution 
panchromatic SPOT image and with 30-m resolution 
multispectral TM images .Moreover, the two-band orthogonal 
wavelet lacks symmetry ,which makes the color of fused image 
not been smoothly integrated into the spatial features.Namely it 
produces some distortion of spectral characteristics in the 
original multispectral images.But biorthogonal wavelet is 
symmetric and multi-band wavelet can effectively fuse diffent 
ratio of spatial resolution .So these problems can be solved if 
integrating multi-band wavelet with biorthogonal wavelet to 
fuse remotely sensed data. So in this paper, we adopt the new 
fusion technique to merge SPOT panchromatic images with 
multispectral TM images.This technique can effectively fuse 
differet or arbitrary ratio of spatial resolution such as 30m- 
resolution TM images and 1 Om-resolution SPOT panchromatic 
images ,and in this approach the color distortion can be reduced 
to a certain extent. 
The structure of this paper is as follows. The first section is 
introduction .In this section mainly introduce the study and 
development on image fusion and the structure of the whole 
* Corresponding author :Liang Shouzhen, E-mail:,liangshzh0816@163.com