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Multitask Sparse Neural Network for Hyperspectral Image Denoising

Data-driven deep learning (DL)-based methods directly learn the nonlinear mapping between noisy hyperspectral images (HSIs) and corresponding clean ones. However, DLbased methods neglect the prior knowledge of HSIs embodied by physical models. Consequently, they require complex network architectures and a large number of training samples. To address the above issues, this paper introduces a multitask sparse neural network (MTSNN) which bridges the sparsity prior of HSIs with data-driven deep learning for HSI denoising. Specifically, we first build a multitask sparse (MTS) denoising model which shares sparse coefficients among bands to exploit the spectral-spatial correlation and learns a dictionary for each band to depict the distinct spatial structure among bands. The iterative optimization of the MTS model is then unfolded to yield our MTSNN by introducing some learnable parameters. MTSNN is a multi-branch network. Each branch performs a single denoising task for an individual band. All branches are connected by shared coefficients, forming multitask denoising for all bands. The hybrid advantages of the MTS model and data-driven learning equip MTSNN with strong denoising ability, preferable learning capability, superior interpretability, and higher generalization capacity. Experimental results demonstrate that our method achieves state-of-the-art denoising performance compared with several alternative approaches.