Distributed Nonlocal Coupled Hierarchical Tucker Decomposition for Hyperspectral Image Fusion.

Hyperspectral image (HIS) super-resolution aims to fuse a low-spatial-resolution HSI (LR-HSI) and a high-spatial-resolution multispectral image (HR-MSI) to obtain a high-resolution HSI (HR-HSI). Tensor-based methods have demonstrated their outstanding ability to construct the relationship between the LR-HSI and the HR-MSI. This letter introduces a nonlocal hierarchical Tucker decomposition (HTD) model for hyperspectral and multispectral image (HSI-MSI) fusion. First, similar nonlocal patch tensors are clustered according to their similarity in the HR-MSI. Next, the spatial/spectral relationship between the LR-HSI and the HR-MSI is extracted through HTD. The alternating direction method of multipliers (ADMMs) is employed to solve the proposed model. Furthermore, to overcome the high computational complexity of the model solver, we propose an efficient distributed and parallel method to accelerate the fusion process. Experimental results demonstrate that the proposed method not only substantially outperforms state-of-the-art HSI-MSI fusion methods, but also achieves a significant acceleration rate.