Application of wavelet transform in image fusion based on remotely sensed data

The wavelet analysis is widely used in different field. The essence of image fusion based on wavelet transform is low-pass filtering and high-pass filtering. The wavelet transform has be employed to merge multi-spectral images and panchromatic images of ETM+ and QB respectively, and that is compared with smoothing filter-based intensity modulation (SFIM) based on low-pass filtering and high-pass filtering transform (HPT). The results show both WT and SFIM have the best low (spectral) frequency preservation with low spatial resolution imageries, while HPT gets most high (spatial) frequency information from high spatial resolution image and will loss much useful spectral information form multi-spectral data.