Bi-Sigmoidal Function Based Adaptive Gamma Correction for Dark Image Enhancement

The proposed Bi-sigmoidal function-based gamma correction method addresses the challenge of enhancing dark images containing light sources. Traditional methods often suffer from over-enhancement in bright regions, leading to information loss and degraded image quality. In contrast, the novel approach employs two modified sigmoidal functions, specifically tailored for dark and bright regions, achieving simultaneous enhancement while maintaining balance. The Bisigmoidal piecewise mapping function estimates local gamma factors based on local mean intensity, ensuring effective enhancement across different intensity regions. Experimental results demonstrate the method's superiority over existing techniques in both objective and subjective measures. By considering local characteristics and employing tailored sigmoidal functions, the proposed method effectively enhances dark images, delivering visually pleasing and high-quality results without sacrificing image details in bright regions.