Unsupervised Sparse Dirichlet-Net for Hyperspectral Image Super-Resolution

TL;DR

This paper introduces an unsupervised deep learning model called uSDN for hyperspectral image super-resolution, effectively fusing low-resolution hyperspectral images with high-resolution multispectral images without requiring large training datasets.

Contribution

It proposes a novel unsupervised encoder-decoder architecture with shared decoding and sparse Dirichlet distribution constraints, addressing spectral and spatial resolution enhancement in HSI-SR.

Findings

uSDN outperforms state-of-the-art methods in experiments.

The model effectively preserves spectral information.

It reduces spectral distortion through angular difference minimization.

Abstract

In many computer vision applications, obtaining images of high resolution in both the spatial and spectral domains are equally important. However, due to hardware limitations, one can only expect to acquire images of high resolution in either the spatial or spectral domains. This paper focuses on hyperspectral image super-resolution (HSI-SR), where a hyperspectral image (HSI) with low spatial resolution (LR) but high spectral resolution is fused with a multispectral image (MSI) with high spatial resolution (HR) but low spectral resolution to obtain HR HSI. Existing deep learning-based solutions are all supervised that would need a large training set and the availability of HR HSI, which is unrealistic. Here, we make the first attempt to solving the HSI-SR problem using an unsupervised encoder-decoder architecture that carries the following uniquenesses. First, it is composed of two encoder-decoder networks, coupled through a shared decoder, in order to preserve the rich spectral information from the HSI network. Second, the network encourages the representations from both modalities to follow a sparse Dirichlet distribution which naturally incorporates the two physical constraints of HSI and MSI. Third, the angular difference between representations are minimized in order to reduce the spectral distortion. We refer to the proposed architecture as unsupervised Sparse Dirichlet-Net, or uSDN. Extensive experimental results demonstrate the superior performance of uSDN as compared to the state-of-the-art.