Advances in Deep Learning for Underwater Image Enhancement: A Systematic Analysis of Architectures, Benchmarks, and Open Challenges
摘要
Underwater Image Enhancement (UIE) plays a key role as a preprocessing step in improving visual quality for applications such as marine exploration, autonomous underwater vehicles, environmental monitoring, and surveillance. However, underwater images often experience problems caused by wavelength-dependent light absorption and scattering. These effects usually result in color distortion, low contrast, and poor visibility. In recent years, deep learning approaches have significantly improved the performance of UIE techniques. Despite this progress, the rapid increase in proposed models, datasets, and evaluation methods has made it difficult to perform systematic comparisons and comprehensive analyses. To address this issue, this study presents a Systematic Literature Review (SLR) of deep learning–based UIE methods. A multi-stage screening and quality assessment process was applied, where more than 2,500 initial records were examined and 196 relevant studies were selected according to predefined inclusion criteria. The selected methods are categorized into main groups: CNN-based, GAN-based, and transformer-based approaches. Their architectures, strengths, and limitations are analyzed in detail. In addition, this study reviews commonly used benchmark datasets and evaluation metrics, highlighting the differences between reference-based and no-reference quality assessment methods. Finally, several key research challenges are discussed, including dataset scarcity, model generalization, computational complexity, and real-world deployment. The paper also outlines future research directions aimed at supporting fair benchmarking and improving reproducibility in UIE research.