Multi-scale retinex-based contrast enhancement method for preserving the naturalness of color image

For images with insufficient visibility, image processing is required. Retinex theory is often implemented for image contrast enhancement for images with this characteristic. This paper proposes a multi-scale retinex-based contrast enhancement method using the illumination component; this method could preserve the naturalness of color images. In the proposed method, illumination was first modified using an illumination modification factor; second, the image was enhanced via adaptive gamma correction. Finally, through the combination of the illumination components of the input image and the adaptive gamma correction image, we ensured the visibility and the naturalness of the output image. To confirm the effectiveness of the proposed method, we compared it with existing contrast enhancement methods. For the experiments, we employed discrete entropy, lightness order error, and mean chrominance error to perform the numerical evaluation. The results indicated that our method was better than a majority of existing methods. Moreover, with regard to the visual evaluation, the naturalness of the image obtained via the proposed method was superior to that of images obtained using other methods.