  Multi-stage architectures have exhibited efficacy in image dehazing, which
usually decomposes a challenging task into multiple more tractable sub-tasks
and progressively estimates latent hazy-free images. Despite the remarkable
progress, existing methods still suffer from the following shortcomings: (1)
limited exploration of frequency domain information; (2) insufficient
information interaction; (3) severe feature redundancy. To remedy these issues,
we propose a novel Mutual Information-driven Triple interaction Network
(MITNet) based on spatial-frequency dual domain information and two-stage
architecture. To be specific, the first stage, named amplitude-guided haze
removal, aims to recover the amplitude spectrum of the hazy images for haze
removal. And the second stage, named phase-guided structure refined, devotes to
learning the transformation and refinement of the phase spectrum. To facilitate
the information exchange between two stages, an Adaptive Triple Interaction
Module (ATIM) is developed to simultaneously aggregate cross-domain,
cross-scale, and cross-stage features, where the fused features are further
used to generate content-adaptive dynamic filters so that applying them to
enhance global context representation. In addition, we impose the mutual
information minimization constraint on paired scale encoder and decoder
features from both stages. Such an operation can effectively reduce information
redundancy and enhance cross-stage feature complementarity. Extensive
experiments on multiple public datasets exhibit that our MITNet performs
superior performance with lower model complexity.The code and models are
available at https://github.com/it-hao/MITNet.
