A New Context-Aware Details Injection Fidelity With Adaptive Coefficients Estimation for Variational Pansharpening

Pansharpening is related to the fusion of a low spatial resolution multispectral (MS) image retaining an abundant spectral content and a high spatial resolution panchromatic (PAN) image to obtain a product with both the abundant spectral content of the former and the high spatial resolution of the latter. Many previous studies are only focused on the global or local relationship between the PAN image and the corresponding high-resolution multispectral (HRMS) image. However, we found that the relationship between PAN and HRMS images in the gradient domain can be better explored through the image context. In this article, we propose context-aware details injection fidelity (CDIF) with adaptive coefficients estimation, which can fully explore the complicated relationship between the PAN image and the HRMS image in the gradient domain. More specifically, we apply a clustering method to divide the pixels of an image into different context-based regions. Afterward, the adaptive coefficients are estimated by using a regression-based method for each region. The CDIF is effective in extracting the main features from the two inputs to be fused. In addition, we integrate the CDIF with a conventional fidelity term and a total variation regularization to formulate a novel variational pansharpening model that is solved by designing an algorithm based on the alternating direction method of multiplier (ADMM) framework. Qualitative and quantitative assessments on different datasets support the effectiveness and robustness of the proposed method. The code is available at https://github.com/liangjiandeng/CDIF.