Pansharpening based on an improved ratio enhancement

Pansharpening technique is very important for many remote sensing applications. Many fusion algorithms have been proposed to pan-sharpen multispectral (MS) images. However, there are still some spatial or spectral distortion problems in fusion result. There are two major reasons: First, panchromatic (PAN) image contains some interference spectrum information similar to MS image which may cause color distortion in the fusion result. Second, MS image has some interference spatial information approximates PAN image which may cause spatial artifacts. It is difficult to simultaneous eliminate the interference information from PAN and MS images. To solve the above problems, the paper presents an improved pan-sharpen algorithm which integrates the advantages of the ratio enhancement method and Gaussian-fitting. The high-frequency information of each i^th band of MS image and the low-frequency information of PAN image are extracted by Gaussian-fitting, and the information is synthesized into a group of low-resolution PAN images. Finally, each i^th band of MS image is pan-sharpened by a ratio enhancement, in which the ratio is obtained by image division between the PAN image and the i^th synthesized low-resolution PAN image. Extensive experiments have been implemented on WorldView-2 images. Visual comparison and quantitative analysis demonstrated that the proposed method can achieve good performance in spatial and spectral fidelity.