Recent advances in pansharpening and key problems in applications

Pansharpening is a process of fusing the spatial detail of a high-resolution panchromatic (Pan) image and the spectral information of a low-resolution multispectral (MS) image to generate a high-resolution MS image. With the fast development of high-resolution satellites, pansharpening techniques are increasingly used worldwide. Even though pansharpening research has been done for decades and numerous techniques have been developed, research efforts are still continuing to further improve the techniques. The most common problems encountered by pansharpening algorithms are colour distortion and spatial artefacts. This article provides a review on recent advances in solving or reducing the problems of colour distortion and spatial artefacts. On the other hand, miss-registration and object size difference between Pan and MS images are also two common key problems in pansharpening applications. Very few publications have discussed these issues. Therefore, this article also addresses these two key problems and provides experimental results to show the capacity of various pansharpening techniques in handling the key problems.