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 M
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FD, show that our method outperforms the state-of-the-art (SOTA) image fusion methods.