Study on Extracting the Colors of Road Network Based on the Highway Traffic Map Images

In recent years, with the aid of computer technology, geographical information system (GIS), which has the ability to handle a large amount of geographical data in it. In particular, substantial efforts are devoted to the conversion of paper-based map into computer readable from which is suitable for input into GIS. This paper puts forward a novel algorithm, which may extract efficaciously the colors of the road network from paper-based highway map images. This algorithm includes several key steps. Firstly, according to the features of the non-road regions, the luminance of the non-road regions is extracted. Secondly, based on the color and shape features, the gray-scale morphology's dilation operator and a median filter are applied to eliminate some thin and small objects of the map image. Finally, taking advantage of some digital image processing technologies such as connection component and thinning algorithm, the colors of the road network are recognized and extract accurately. This algorithm has been applied to many highway traffic map images. It is shown that the algorithm is effective in various cases successfully.