Modified Visibility Restoration-Based Contrast Enhancement Algorithm for Colour Foggy Images

Abstract

The visibility enhancement of colour foggy images is a very challenging task for many real-time applications. In this paper, we have proposed an efficient and robust algorithm for visibility enhancement of colour foggy images. The proposed algorithm works in two steps: in the first step, modified visibility restoration algorithm is applied for visibility enhancement, and in the second step, sigmoid-function-based contrast enhancement technique is applied for colour contrast enhancement of images. The quantitative and qualitative results of proposed and other state-of-the-art algorithms for colour foggy images are obtained in terms of fog aware density evaluator, fog reduction factor (FRF), measure of enhancement (EME), and measure of enhancement factor (EMF) on different colour foggy image databases. Results reveal the strength of proposed algorithm mathematically on the basis of fog thickness estimation from original image and output-enhanced image, FRF, EME, and EMF for colour foggy images. Experimental results shows that the proposed algorithm provides better quantitative and qualitative results as compared to other state-of-the-art algorithms for colour foggy images. Finally, the proposed algorithm is highly efficient for visibility enhancement of colour foggy images.