ABSTRACT
Pansharpening refers to the fusion of a panchromatic (Pan) and a multispectral (MS) image acquired on the same area, simultaneously in most cases, but not necessarily. This can be seen as a particular problem of data fusion, since one would aim to combine the spatial details resolved by Pan, but not by MS, and the spectral diversity of MS, which is missing in Pan, in a unique product. With respect to the general problem of multisensor fusion, pansharpening may not require the challenging phase of spatial coregistration, since all images are typically acquired simultaneously, the Pan and MS sensors being both mounted on the same platform. Nowadays, Pan and MS images can be obtained in bundle by several commercial optical satellites such as IKONOS,
OrbView, Landsat 8, SPOT, QuickBird, and WorldView-2. The spatial resolution is even below half meter for the Pan (resulting in the commercial satellite product with the highest spatial resolution) and the spectral resolution can be up to eight bands captured in the visible and near-infrared (V-NIR) wavelengths for MS. The fusion of MS and Pan images constitutes the sole possibility of achieving images with the highest resolutions in both the spatial and spectral domains. In fact, physical constraints of imaging devices prevent this goal from being achieved through a single instrument.
