Measurement Of Haze Visibility Based On Video Analysis

On haze days,many traffic scenes need to measure the visibility of the current scene.Traditional methods usually use related hardware to measure or eyes to estimate.These methods often cost high or can't measure precisely.Moreover,due to the limitation of the cost,it is difficult to popularize and measure the visibility of specific scenes timely.Therefore,this paper proposes a measurement method based on video images.It uses the current traffic cameras to obtain video images and then to calculate the visibility value.Since it does not need additional hardware and with the advantage of measuring precisely,it has more practical application value.The main work of this paper is as follows:This paper introduces the current research of the visibility measurement and analyses the advantages and disadvantages.Besides,we also study the measuring principles of the visibility on haze days.Based on the atmospheric light model,we deduce the basic formula to calculate the visibility.Based on the traffic videos,this paper turns the issue of visibility measurement into the issue of the contrast ratio of the target object and background,and gives the measuring method that analyses the images.Due to the problems of the ROI of the target object and background,this paper makes the rules to choose the ROI we need.Using the technology of image segmentation,it extracts the background and target object and then gives the detail steps to calculate the visibility.Based on the formula to calculate the visibility,this paper analyses the related steps and the algorithm.It includes the calculation of the current contrast ratio and the inherent contrast ratio.Furthermore,this paper introduces a method based on multi depths of field to calculate the inherent contrast ratio.The basic idea is to use the videos where thedifferent depths of different target objects in multiple frames based on the least square method.Finally,with the depth of the target object and the contrast ratio,we can calculate the visibility value.In order to test the effectiveness of the method,this paper chooses different scenes and compares with the mainstream methods.The results shows that the method this paper proposes works well.