Using QNR index as decision criteria for improving fusion quality

Pansharpening is the process of improving spatial resolution of multispectral (MS) satellite images using the spatial details of a high resolution panchromatic (PAN) image. Quality without reference (QNR) index is a tool which can be used to determine the global quality of the fused images without requiring a high resolution reference MS image. Over the years different pansharpening methods have been proposed using different criteria to obtain improved fusion quality. Since QNR can be used to determine the quality of fused images at full resolution without requiring a reference high resolution MS image, it may be used as a decision criterion to select the best fused regions, given a number of different fused images. In this paper we propose to use the QNR index to determine the local fusion quality. We also extend this property of local quality assessment to select regions among various fused images of the same region to obtain a single image with the best quantitative measures. The proposed decision fusion is tested on Pleiades and Quickbird satellite images fused by recently proposed fusion methods.