An Automatic Normalizing Algorithm of the urban Maps

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 an automatic normalizing algorithm, which is a pre-processing scheme for extracting road network from paper-based urban maps. Firstly, some measures are built, which based on the features of roads and non-road regions, such as the texture features of roads and non-road regions. Secondly, the measures are applied to extract the luminance of all roads and non-road regions form urban maps. Finally, taking advantage of the extracted luminance of roads and non-road regions, the image normalizing procedure is implemented. This algorithm has been applied to many urban maps. It is shown that the algorithm is effective in various cases successfully