A Semi-Supervised Network Framework for low-light image enhancement

Abstract

Existing supervised learning-based low-light image enhancement algorithms treat all degradations as a whole, resulting in limited enhancement performance. It is difficult for fully unsupervised learning to recover more hidden details, making the augmented results unsatisfactory for visual needs. To overwhelm the limitations of supervised and unsupervised learning, we propose a Semi-Supervised Network Framework (SSNF) to enhance low-light images. Specifically, we decouple the low-light image enhancement task into two stages. In the first stage of the SSNF, we employ methods based on information entropy and Retinex to improve the visibility of images. It is worth mentioning that this stage is a lightweight self-supervised network, which only needs to input low-light images and undergo minute-level training to achieve brightness improvement. In the second stage of the SSNF, we utilize U-Net and residual networks to remove problems such as noise and degradation existing in the first-stage enhancement results, thereby improving the visual properties of the enhanced images. It overwhelms the challenge of dealing with low-light images directly. We conduct extensive experiments on datasets such as LOL, synthetic, DICM, etc. The experimental results show that SSNF exhibits better visual effects and outperforms other advanced methods in performance metrics.