A Survey of Pansharpening Methods with A New Band-Decoupled Variational Model

TL;DR

This paper introduces a novel band-decoupled variational model for pansharpening that improves spatial detail preservation and reduces spectral distortions by avoiding linear assumptions and maintaining radiometric ratios.

Contribution

The paper proposes a new optimization-based pansharpening method that decouples spectral bands and preserves radiometric ratios, outperforming existing techniques.

Findings

Superior spatial detail preservation

Reduced color distortions

Minimized aliasing artifacts

Abstract

Most satellites decouple the acquisition of a panchromatic image at high spatial resolution from the acquisition of a multispectral image at lower spatial resolution. Pansharpening is a fusion technique used to increase the spatial resolution of the multispectral data while simultaneously preserving its spectral information. In this paper, we consider pansharpening as an optimization problem minimizing a cost function with a nonlocal regularization term. The energy functional which is to be minimized decouples for each band, thus permitting the application to misregistered spectral components. This requirement is achieved by dropping the, commonly used, assumption that relates the spectral and panchromatic modalities by a linear transformation. Instead, a new constraint that preserves the radiometric ratio between the panchromatic and each spectral component is introduced. An exhaustive performance comparison of the proposed fusion method with several classical and state-of-the-art pansharpening techniques illustrates its superiority in preserving spatial details, reducing color distortions, and avoiding the creation of aliasing artifacts.