Infrared-Visible Image Fusion Using Dual-Branch Auto-Encoder With Invertible High-Frequency Encoding

In the field of Infrared-Visible Image Fusion (IVIF), the preservation of details, edges, and texture is crucial for generating high-quality fused images. However, a major challenge arises due to the inevitable loss of high-frequency information during feature extraction, resulting in fused images that lack significant details. In this paper, we propose a dual-branch auto-encoder by exploiting an invertible high-frequency branch for detailed feature preservation and a transformer-based low-frequency branch for global dependencies modeling. First, the high-frequency branch employs the wavelet transforms and an Invertible Neural Networks (INN)-based encoder to model high-frequency features through an invertible transformation, including a forward process for image fusion and an inverse process for original image reconstruction. Additionally, a high-frequency loss is designed to enhance the high-frequency feature representation for high-quality image fusion. Second, a low-frequency branch based on a transformer encoder and an adaptive fusion module is introduced to capture the global contextual features of the infrared and visible images. Finally, the decoder integrates the low- and high-frequency features from both branches to generate the final fused image. Image fusion, object detection, and semantic segmentation experiments conducted on public datasets such as TNO, MFNet, and M3FD, show that our method outperforms the state-of-the-art (SOTA) image fusion methods.