<p>Images captured in low-light environments often suffer from poor visibility and low contrast. Although numerous enhancement techniques have been proposed, most existing methods, while improving brightness and contrast, tend to lose fine details or introduce unnatural artifacts caused by over-enhancement. To address these limitations, this paper proposes a novel image enhancement method that integrates dark region adjustment, image sharpening, and contrast enhancement. The method leverages parametric S-shaped functions: an inverse S-shaped function is first applied to selectively enhance dark regions, followed by multi-scale enhancement with standard S-shaped functions to improve sharpness and contrast while preserving details. In addition, a hue-preserving process is incorporated to maintain natural color appearance. Extensive qualitative and quantitative evaluations demonstrate that the proposed method effectively overcomes the limitations of conventional methods.</p>