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A road extraction method from topographical map images

This paper describes an automatic road extraction method from color map images. This method has been developed as a part of a research on automated geographic database extraction from scanned color maps. In many cases, maps are constructed in a number of layers, where each layer is printed in a distinct color, and it represents a subset of the map information. The proposed method consists of color separation, road image restoration, and extraction of the skeleton. To obtain accurate road information from the color-separated road image, a new road image restoration algorithm is proposed. This algorithm is based on the conditional dilation operation of mathematical morphology and has an advantage in regard to reducing the various kinds of distortions, compared with using conventional processes. Through map input experiments with the method, the desired road information is efficiently extracted.