The Research On Image Defogging Algorithm And Its Application In Traffic Surveillance Video

In foggy conditions,the images collected by the outdoor computer vision system will be greatly degraded,such as contrast decline,color distortion.In recent years,the fog weather frequently appears,this result in a significant negative impact on the use of outdoor computer vision system,so it's of great value to have a study on image defogging.Based on fog image enhancement and fog image restoration,paper has a study on image defogging technology,establishes the guidelines that “ensure the defogging effect and enhance the speed as far as possible ”,makes some improvements for the related algorithms.Applying the image defogging algorithm in practical application to verifies it's effectiveness.The main work of the paper is as follows:(1)In terms of image enhancement,paper analyzes the defogging effect of histogram equalization algorithm and Retinex algorithm.Enhanced by Retinex algorithm,the foggy image will appear color distortion,aiming at this defect,paper use multi-scale Retinex which based on HSV color space but not RGB color space to enhance the foggy image.In HSV color space,lightness component V and hue component H are uncorrelated,based on this characteristics,when enhancing the component V,component H remains unchanged.Experimental results show that the proposed algorithm have a better enhance result on colorful image,at the same time,as only to enhance component V,the proposed algorithm is faster.(2)In respect of image restoration,the paper is focusing on the studying of the image defogging algorithm based on dark channel prior.In order to eliminate the halo effect,original algorithm use the soft matting method to repair the transmittance map,this lead to the complexity of the algorithm highly,and computing speed slow.In this paper,smoothing the transmittance map is processed by adaptive bilateral filtering algorithm which replace the original soft matting,and use the down-sampling method to make the speed faster.Simulation results validate that the proposed algorithm can effectively eliminate the halo effect and the speed of the algorithm has been greatly improved.(3)Based on the theoretic research,the defogging algorithm is applied to the situation of road traffic monitoring.Based on the features of traffic video monitoring,using a suitable defog algorithm in different foggy weather grade so that it enables the system to have a well-targeted defogger in different foggy weather conditions.