An improved adaptive IHS method for image fusion

Abstract

ABSTRACT An improved adaptive intensity-hue-saturation( IHS) method is proposed for image fusion in this paper based on the adaptive IHS(AIHS) method and its improved method(IAIHS). Through improved method, the weighting matrix, which decides how many spatial details in the panchromatic(Pan) image should be injected into the multispectral(MS) image, is defined on the basis of the linear relationship of the edges of Pan and MS image. At the same time, a modulation parametert is used to balance the spatial resolution and spectral resolution of the fusion image. Experiments showed that the improved method can improve spectral quality and maintain spatial resolution compared with the AIHS and IAIHS methods. Keywords: Image fusion, IHS, MS image, Pan image, linear factor, modulation parameter . 1. INTRODUCTION Most earth observation satellites(such as Landsat, IKONOS, Quick Bird) provide two types of remote sensing images: the one is Pan image which has high spatial resolution but low spectral resolution, the other one is MS image which has high spectral resolution but low spatial resolution. In order to satisfy the application requirements that remote sensing image should have both high spatial and spectral resolution. A series of image fusion methods emerged. The image fusion usually can be divided into two steps: first, extracting spatial details from Pan image which has high spatial information; second, integrating the spatial details in to the low spatial MS image by certain algorithms, to get an MS image that has both high spatial and spectral resolution. On the current research, image fusion algorithms have two major categories: the first category is the component replacement (CS) method, representative methods have intensity-hue-saturation(IHS)[1] transformation algorithm, principal component analysis(PCA)[2] method and brovey transform(BT)[3] et al. The second category is multiresolution(MRA) analysis, there are some classic methods such as Laplacian pyramid[4], Wavelet transform method[1] and Discrete wavelet transform method[5] et al . The IHS method, as a classical CS algorithm, has been used to many commercial software because of its high efficiency and speed. Though IHS merge method can get superior spatial resolution, it also exist serious spectral distortion and make the image have wrong color distribution. Original IHS merge method can justly apply to red, green, blue three bands, unable to meet the need of image fusion of modern remote sensing satellites. To conquer these defects, a great deal of scholars have done numbers of improvement, Tu et al[6] proposed Fast IHS image fusion algorithm, which not only had high