The Research And Implementation Of The Remote Sensing Image Fusion Based On Curvelet Transform

The fusion of high-spectral/low-spatial resolution multispectral and low-spectral/high-spatial resolution panchromatic satellite images is a very useful technique in various applications of remote sensing. Recently, some studies showed that a wavelet-based image fusion method provides high quality spectral content in fused images. However, most wavelet-based methods yield fused results with spatial resolution that is less than that obtained via the Brovey, IHS, and PCA fusion methods. Since edges play a fundamental role in image representation for two-dimensional images, one effective means to enhance spatial resolution is to enhance the edges. In this paper, we introduce a new method based on curvelet transform, which represents edges better than wavelets. We also use wavelet-based method in the fusing method, so the curvelet-based image fusion method provides richer information in the spatial and spectral domains simultaneously.The experiment has been accomplished with Landsat ETM+ image and SPOT panchromatic image of HuangNan City. We choosed four test-sections with characteristic geographical objects and used many fusing methods.From the experimental results, we firstly make a visual analysis. We can see the wavelet transform preserves the spectral information of the original multispectral images, it has the high spectral resolution in contrast with the IHS-based fusion result, which has some colour distortion. But the wavelet-based fusion result has much less spatial information than that of the IHS-based fusion result. The curvelet transform in image fusion overcome these problems, it is well adapted to represent panchromatic image containing edges, the curvelet based fusion results have both high spatial and spectral resolution.We also conducted a quantitative analysis , The experimental results were analysed based on many indicators such as entropy, correlation coefficient, and so on. These indicators all can reflect the quality of the fused images, and the conclution is : This new method has yielded optimum fusion result and is superior to the wavelet and IHS methods, visually and quantitatively, for the fusion of ETM+ multispectral image and SPOT panchromatic image.