| Liu, Jia, Luo, Yu, Yue, Guanghui, Ling, Jie, Liao, Liang, Lin, Chia-Wen, Zhai, Guangtao and Zhou, Wei 2026. Self-supervised unfolding network with shared reflectance learning for low-light image enhancement. IEEE Transactions on Image Processing 10.1109/tip.2026.3652021 |
Abstract
Recently, incorporating Retinex theory with unfolding networks has attracted increasing attention in the low-light image enhancement field. However, existing methods have two limitations, i.e., ignoring the modeling of the physical prior of Retinex theory and relying on a large amount of paired data. To advance this field, we propose a novel self-supervised unfolding network, named S2UNet, for the LIE task. Specifically, we formulate a novel optimization model based on the principle that content-consistent images under different illumination should share the same reflectance. The model simultaneously decomposes two illumination-different images into a shared reflectance component and two independent illumination components. Due to the absence of the normal-light image, we process the low-light image with gamma correction to create the illumination-different image pair. Then, we translate this model into a multi-stage unfolding network, in which each stage alternately optimizes the shared reflectance component and the respective illumination components of the two images. During progressive multi-stage optimization, the network inherently encodes the reflectance consistency prior by jointly estimating an optimal reflectance across varying illumination conditions. Finally, considering the presence of noise in low-light images and to suppress noise amplification, we propose a self-supervised denoising mechanism. Extensive experiments on nine benchmark datasets demonstrate that our proposed S2UNet outperforms state-of-the-art unsupervised methods in terms of both quantitative metrics and visual quality, while achieving competitive performance compared to supervised methods. The source code will be available at https: //github.com/J-Liu-DL/S2UNet.
| Item Type: | Article |
|---|---|
| Date Type: | Published Online |
| Status: | In Press |
| Schools: | Schools > Computer Science & Informatics |
| Publisher: | Institute of Electrical and Electronics Engineers (IEEE) |
| ISSN: | 1057-7149 |
| Last Modified: | 19 Jan 2026 14:30 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/184022 |
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