Extracting Roadway Background Image: a Mode-Based Approach

Traffic monitoring cameras are widely installed on streets and freeways in U.S. metropolitan areas. Video images captured from these video cameras can be used to extract many valuable traffic parameters through video image processing. A popular way to capture these traffic data is to compare the current traffic images with the background image, which contains no vehicles or other moving objects, just background such as pavement. Once the moving vehicle images are separated from the background image, measurements of their number, speed, etc. can be obtained. Background images are typically extracted from a video stream through image processing because, for normal traffic streams on urban streets, it may be hard to find a frame without any vehicles. This paper introduces a new method that can quickly extract the background image from traffic video streams for both freeways and intersections in a variety of prevailing traffic conditions. This method has been tested with field data and the results are promising. Zheng, Wang, Nihan, and Hallenbeck 3