Fusion of Multispectral and Panchromatic Images and Its Quality Assessment

Image fusion is the process of merging two or more images obtained from the same sensor at different times or from two or more sensors at the same instant. The objective is to obtain more information from the fused image than from the individual images. In satellite images, the lower spatial resolution multispectral images are fused with higher spatial resolution panchromatic images. The fusion should result in the transfer of spectral and spatial information without introducing any artifacts. The goal is to combine the spectral and spatial resolutions of the multispectral and the panchromatic images respectively to obtain a high-resolution multispectral image. Most of the fusion techniques that have been proposed are based on the compromise between the desired spatial enhancement and the spectral consistency. This paper provides an overview of the techniques available in the literature for the fusion of multispectral and panchromatic images. The evaluation of the fusion technique employed is also an important step in the fusion process. Various quality metrics have been used in the literature to study, compare and assess the fusion technique employed. This paper provides a brief study on such quality metrics employed in the literature.