Proceedings Article | 10 November 2004
KEYWORDS: Image fusion, Wavelets, Image quality, Earth observing sensors, Image processing, Spatial resolution, Satellite imaging, Satellites, Wavelet transforms, Spectral resolution
Lately, different methods for the fusion of multi-spectral and panchromatic images based on the Wavelet transform have been proposed. Even though, most of them provide satisfactory results, there is one, the algorithm a trous, which presents some advantages against the other fusion methods based on Wavelet transform. Thus its computation is very simple, it only implies elemental algebraic operations, such as products, differences and convolutions. Moreover it yields a better spatial and spectral quality than the others. On the other hand, it is well known that standard fusion methods do not allow to control the spatial and the spectral quality of the fused image. If the spectral quality is very high, this implies a low spatial quality and vice versa. In this sense, here, it is proposed a new version of a fusion method based on the Wavelet transform, computed through the algorithm à trous, which allows to customize the trade-off between the spectral and the spatial quality of the fused image by the evaluation of two quality indices: one spectral index, the ERGAS index, and other spatial one. For this last one, a new spatial index based on ERGAS concepts, translated to the spatial domain has been defined. Moreover, in this work, several different architectures for the computation of the investigated fusion method has been evaluated, in order to determine the optimize degradation level of the source image, required to perform the fusion process. The performances of the proposed fusion method have been compared with the fusion method based on Hierarchic Wavelet.
