<title>Data fusion of SPOT and Landsat images using additive multiresolution wavelet decomposition</title>

Abstract

In this paper we present the development of a technique, based on multiresolution wavelet decomposition, for the merging and data fusion of a high-resolution panchromatic image and a low- resolution multispectral image. The method presented here consists of adding the wavelet coefficients of the high- resolution image to the multispectral (low-resolution) data. We have studied several possibilities concluding that the method which produces the best results consists in adding the high order coefficients of the wavelet transform of the panchromatic image to the intensity component (defined as L equals R+G+B/3) of the multispectral image. Using this method, the detail information from both images is preserved. The method is capable of enhancing the spatial quality of the multispectral image while preserving its spectral content to a greater extent. The method presented does not modify the total energy of the multispectral image, since the mean value of each of the added wavelet planes is 0. The method is, thus, an improvement on standard Intensity-Hue-Saturation (IHS or LHS) mergers. We used the method to merge SPOT and LANDSAT (TM) images. The technique presented is clearly better than the IHS and LHS mergers in preserving both spectral and spatial information.