Multi-band wavelet for fusing SPOT panchromatic and multispectral images

With the development of remote sensing technology, fusion of remotely sensed images, such as SPOT panchromatic (SPOT P) with SPOT multispectral images (SPOT XS) or Landsat Thematic Mapper (TM), has become more important in order to obtain richer information in the spatial and spectral domains simultaneously. Many fusion methods have been developed based on the two-band wavelet transformation. However, due to the limitations of the transformation characteristics themselves, the two-band wavelet is not very efficient for the fusion of images whose ratio of spatial resolutions is not 2n(n = 1, 2, 3, ...), e.g., for fusing a 10-m resolution panchromatic SPOT image and with 30-m resolution multispectral TM images. However, a recently developed new wavelet branch - multi-band wavelet - can potentially be applied to solve this problem. In this paper, we develop a new approach for fusing SPOT P images with multispectral TM images based on multi-band wavelet transformation. First, the theoretical basis of multi-band wavelet is presented and its transformation properties are analyzed. Second, a new method for fusing a SPOT P image with multispectral images using the multi-band wavelet is proposed. Specifically, the three-band wavelet is implemented to fuse 10-m SPOT panchromatic and 30-m multispectral TM images. Third, this new method is compared with previous methods such as the two-band wavelet and IHS methods for image fusion. The proposed multi-band wavelet approach demonstrates an improvement in spatial and spectral characteristics for fusing SPOT P and multispectral TM images.