  Image fusion aims to generate a high-quality image from multiple images
captured under varying conditions. The key problem of this task is to preserve
complementary information while filtering out irrelevant information for the
fused result. However, existing methods address this problem by leveraging
static convolutional neural networks (CNNs), suffering two inherent limitations
during feature extraction, i.e., being unable to handle spatial-variant
contents and lacking guidance from multiple inputs. In this paper, we propose a
novel mutual-guided dynamic network (MGDN) for image fusion, which allows for
effective information utilization across different locations and inputs.
Specifically, we design a mutual-guided dynamic filter (MGDF) for adaptive
feature extraction, composed of a mutual-guided cross-attention (MGCA) module
and a dynamic filter predictor, where the former incorporates additional
guidance from different inputs and the latter generates spatial-variant kernels
for different locations. In addition, we introduce a parallel feature fusion
(PFF) module to effectively fuse local and global information of the extracted
features. To further reduce the redundancy among the extracted features while
simultaneously preserving their shared structural information, we devise a
novel loss function that combines the minimization of normalized mutual
information (NMI) with an estimated gradient mask. Experimental results on five
benchmark datasets demonstrate that our proposed method outperforms existing
methods on four image fusion tasks. The code and model are publicly available
at: https://github.com/Guanys-dar/MGDN.
