A hue preserving uniform illumination image enhancement via triangle similarity criterion in HSI color space

Color images are essential in computer vision applications such as surveillance and security systems. However, due to the low light conditions, the color of the obtained image deviates from the original color. Moreover, it would produce inaccurate results that limit the performance of these applications. Therefore, this paper proposes a hue preserving uniform illumination image enhancement via triangle similarity criterion in hue–saturation–intensity (HSI) color space. Based on this, the proposed method develops translation and scaling operations to enhance the intensity and saturation. These enhancement processes maintain the hue and features while having minimal effect on the mean brightness. The proposed method and five model-based enhancement methods are evaluated from five perspectives: subjective visual evaluation, the hue and features preservation capabilities, the ability to enhance the contrast and visual information, mean brightness preservation capability, and computational complexity. Results indicate that the proposed method produces better-enhanced images than the other five model-based enhancement methods.