Visibility improvement of hazy images using manipulation of convex combination coefficients of equi-hue planes’ vertices in the RGB color space

Images captured in foggy or hazy environments exhibit whitening and reduced contrast. Various methods have been proposed to enhance the visibility of hazy images with degraded quality. However, these conventional methods may cause degradation of the resultant image, such as unnatural color changes and artifacts. To address this problem, we propose a haze-removal method for image visibility improvement using manipulation of convex combination coefficients of equi-hue planes’ vertices, which correspond to white, black, and pure colors in the RGB color space. The proposed method begins with a pre-processing step involving contrast enhancement of the lightness component using a multi-scale image enhancement method with S-shaped functions. Then, for saturation enhancement, the convex combination coefficients of white are reduced, and those of pure colors are increased in the lightness-enhanced image to achieve haze removal. Experiments were conducted using real hazy images and artificially synthesized images, and the effectiveness of the proposed method was verified by comparison with conventional methods. The experimental results demonstrate that the proposed method effectively enhances the visibility of hazy images while minimizing unnatural color changes and artifacts.