Spatial Resolution Enhancement of Prisma Hyperspectral Data Via Nested Hypersharpening with Sentinel-2 Multispectral Data

The paper presents an original method for the spatial resolution enhancement of the hyperspectral (HS) data from PRISMA (Italian acronym for Hyperspectral Precursor of the Application Mission) by means of the Sentinel-2 visible and near infrared (VNIR) and shortwave infrared (SWIR) bands at 10 and 20 m spatial resolution, and the 5 m panchromatic (PAN) band also acquired by the PRISMA satellite. Firstly, the 20 m bands of Sentinel-2 are hypersharpened to 10 m by means of the four 10 m VNIR bands of the same instrument. Then, the 10 m hypersharpened bands of Sentinel-2 are used to sharpen the 30 m bands of PRISMA to 10 m as well, still according to the hypersharpening protocol. Eventually, the 10 m hypersharpened bands of PRISMA are pansharpened to 5 m by means of the Pan image of the same satellite. Results show that the nested hypersharpening followed by pansharpening is better than plain HS pansharpening, both visually and according to established full-scale indexes of spectral and spatial consistence