An optimized approach for pansharpening very high resolution multispectral images

State-of-the-art pansharpening methods generally inject the spatial details extracted from the panchromatic (Pan) image into the multispectral (MS) images by considering different injection models. The fusion performances severely rely on the accuracy of the modeling and the estimation of model parameters. In this letter, we propose an optimized approach to avoid explicitly modeling the detail injection process. The solution employs the gradient field of the Pan image for spatial enhancement. The low-pass (LP) version of the fused bands are constrained to be the most similar to the original MS bands to preserve the spectral characteristics. We use the local correlation coefficients between the MS band and the LP version of the Pan image to adjust the two sources of information based on a simple observation, and it is further optimized by considering the overall quality index Q4. Experimental results demonstrate that the proposed method outperforms the state-of-the-art multiresolution analysis-based methods.