Enhancing Spatial Resolution of Sentinel-2 Next Generation Imagery via Image Fusion

This study presents the analysis of different data fusion techniques to improve the spatial resolution of spaceborne optical images. It was carried out in the context of designing a companion satellite for the Sentinel 2 Next Generation (S2NG) mission, planned to be equipped with either a 2.5 m panchromatic sensor or a three-band multispectral sensor at 2.5 m spatial resolution centered at the red, green, and blue wavelengths. Hence, two primary fusion techniques were investigated: Pansharpening, using a high-resolution panchromatic image, and multisharpening, using a high-resolution multispectral image. To this aim, S2NG test images were synthesized from airborne hyperspectral data. The study explores the effectiveness of both pansharpening, using synthetic panchromatic images, and multisharpening, which directly combines high-resolution RGB with multispectral images. The performance of these techniques was validated using the HQNR index, taking into account both spectral and spatial distortions. In addition, the robustness of these methods against noise and co-registration errors was evaluated. The results indicate that multisharpening provides superior quality enhancement, particularly under varying noise conditions, making it a viable option for future satellite missions requiring high-resolution data fusion.