A SIMPLE SCHEME FOR COUPLED FACTORIZATION FOR HYPERSPECTRAL SUPER-RESOLUTION: EXPLOITING SPARSITY IN AN EASY WAY

In this paper we develop a simple scheme for a coupled matrix factorization problem arising in the topic of hyperspectral super-resolution (HSR). HSR considers the problem of recovering a super-resolution image from a multispectral image and a hyperspectral image, which have lower spectral and spatial resolutions, respectively, and it is a motivated topic in the domain of remote sensing. The challenge with coupled factorization (COFAC) is that we are required to simultaneously factorize two data matrices, with their factors being interrelated. We adopt a separable COFAC strategy, in which we first factorize one data matrix, and then use the retrieved factors and the coupled factor relationship to help us factorize an- other matrix; the merit is that it may lead to simple COFAC schemes. Our scheme is based on the simplex-structured factorization model, which is commonly used in HSR, and a sparse factor assumption. In particular we leverage on the coupled factor structure to exploit sparsity in an easy way; we solve simple constrained least squares problems, and we sidestep the need to do sparse optimization. Numerical results show that our proposed scheme works reasonably on both semi-real data and synthetic data, and it runs much faster than some state-of-the-art COFAC schemes.