Spectral Super-Resolution in Frequency Domain

Spectral super-resolution aims to reconstruct a hyperspectral image (HSI) from its corresponding RGB image, which has drawn much more attention in remote sensing field. Recent advances in the application of deep learning models for spectral super-resolution have demonstrated great potential. However, these methods only work in spectral-spatial domain while rarely explore the potential property in the frequency domain. In this work, we first attempt to address spectral super-resolution in the frequency domain. To well merge the frequency information into the super-resolution network, a spectral-spatial-frequency domain fusion network (SSFDF) is designed, which consists of three key parts: frequency-domain feature learning, spectral-spatial domain feature learning, and feature fusion module. In more detail, a frequency-domain feature learning network is first exploited to dig the frequency-domain information of the input data. Then, a symmetric convolutional neural network (CNN) is developed to acquire the spectral-spatial features of the input data, where a parameter-sharing strategy is utilized to reduce network parameters. Finally, a feature fusion module is proposed to reconstruct HSI. Comprehensive experiments on several datasets reveal that our method can attain state-of-the-art reconstruction result with respect to other spectral super-resolution techniques.