Fog removal techniques from images: A comparative review and future directions

Fog, haze and smoke are a big reason of road accidents. Fog reduces contrast level of the image that affects the visual quality of the image. In field of computer vision visual quality and visibility level of an image is affected by airlight and attenuation phenomena. Air particles, which present in atmosphere and affect the visibility level of any object, are called noise or unwanted signal between observer and object. For improving the visibility level of an image and reducing fog and noise various image enhancement methods are used. After enhancement is again restored the enhanced image by restoration methods. For improving the visibility level 4 major steps are used. First step is acquisition process of foggy images. Second is estimation process (estimate scattering phenomena, visibility level). Third is enhancement process (improve visibility level, reduce fog or noise level). Last step is restoration process (restore enhanced image). The main aim of this paper is to review state-of-art image enhancement and restoration methods for improving the quality and visibility level of an image which provide clear image in bad weather condition. We also compare prevalent approaches in this area through implementation of the methods keeping parameters common for critical analysis. In the end we provide the future scope for working directions in this area for the readers.