Full-resolution quality assessment for pansharpening

A reliable quality assessment procedure for pansharpening methods is of critical importance for the development of the related solutions. Unfortunately, the lack of ground-truths to be used as guidance for an objective evaluation has pushed the community to resort to either reference-based reduced-resolution indexes or to no-reference subjective quality indexes that can be applied on full-resolution datasets. In particular, the reference-based approach leverages on Wald's protocol, a resolution degradation process that allows one to synthesize data with related ground truth. Both solutions, however, present critical shortcomings that we aim to mitigate in this work by means of an alternative no-reference full-resolution framework. On one side we introduce a protocol, namely the reprojection protocol, which allows to handle the spectral fidelity problem. On the other side, a new index of the spatial consistency between the pansharpened image and the panchromatic band at full resolution is proposed. The experimental results show the effectiveness of the proposed approach which is confirmed also by visual inspection.