Academia.eduAcademia.edu

Image Processing Technique for Traffic Density Estimation

2017, International Journal of Engineering and Technology

Abstract

Various techniques for the traffic density estimation in heavy traffic have been developed widely. However, most of them suffer from any drawbacks, especially for traffic fulfilling all kinds of vehicles. In the present study, a new technique of traffic density estimation using a macroscopic approach has been developed. This technique used a background construction and a traffic density estimation algorithm. The first algorithm detects parts of the image containing no moving vehicle in front of or behind the moving vehicle using inter-frame difference. After that, an edge detector detects the edge of image part and classifies whether the image can be used as a part of the background image or not. Meanwhile the second algorithm estimates the traffic density by calculating a ratio between the road area covered by vehicle and the total road area. As a result, this technique has a higher accuracy for determining the traffic density compared with the previous techniques. Traffic density estimation is one of the challenging problems in traffic control systems. This provides important data for traffic controlling, routing, and vehicular network traffic scheduling. Drivers choose lanes based on the traffic density information. Therefore, providing the least delay of the real time traffic density information plays an important role on the intelligent transportation systems. Conventional technology for determining the traffic density, such as inductive loops, sonar or microwave detectors, lacks of some drawbacks. They are expensive to install, not portable, unable to detect slow or stationary vehicles and demanding traffic disruption during installation or maintenance. On the contrary, video based systems have some advantages. They are easy to install, as a part of ramp meters and use in the existing traffic surveillance infrastructure . They can be easily upgraded and offer the flexibility to redesign the system and its functionality. Furthermore, those systems also allow vehicle counting, attributes classifying (color, license plate, logo and type) and vehicle's speed measuring . Recently, some image processing techniques have been developed to estimate the traffic density. The techniques generally comprise thresholding, multi-resolution processing, edge detection, background subtraction and inter-frame differencing . There are two approaches for road traffic density estimation, microscopic and macroscopic approach . The microscopic approach uses parameters obtained by averaging some parameters of all individual vehicles on the road. These parameters are estimated by detecting each vehicle on the road, calculating the number of the vehicle, and then determining the traffic density. The microscopic approach produces a low accuracy because of it dependence on the quality of the environment, such as lighting and weather . Moreover, it cannot be performed reliably on low resolution images or when there are many objects on the scene, for example, on the crowded highway scenes . Another approach, macroscopic approach recovers a holistic representation of traffic flow information directly, without detecting vehicle. This approach directly estimates the traffic density by analyzing the global motion on the video scene. The macroscopic approaches have been developed by some researchers. Porikli and Li [6] proposed an unsupervised, low-latency traffic congestion estimation algorithm that operates on the MPEG video data. Both extracted congestion features directly on the compressed domain, and employed Gaussian Mixture Hidden Markov Models (GM-HMM). The algorithm could detect the traffic condition but it needs a huge computation loads.