Study On Pick-up Foreground Elements From The Pixel Map

It is the pivotal technology field to get the geometric data effectively with the quick development of information technology and the Geographic Information System. The establishment of the geography information database needs to deal with a great deal of map. This work by hand is very hard and taken place the mistake easily. So automatic getting the data from the map by picture processing technique is a hot study point currently. In this course, how to get the foreground elements from the map is the key and difficult point. In this paper, three steps are given to solve the problem.First, a kind of Fuzzy-gradient Algorithm is presented on the basis of analyzing the characteristics of maps, in which the idea of fuzzy sets and gradient are used. It solve the problem which the general methods can not pick-up the fuzzy foreground elements from the map clearly.Second, after removing the background of the map, a optimal-component method is presented to divide one kind foreground elements from the foreground. This method is simple and reflects the space and color characteristics of foreground element.Third, a method base on characteristics of gradient is presented. With this method, the time of thinning are reduced and bring about very effect. Final, after-processing is processed with mathematical morphology.The course by this paper's method is very automatic and easy. The time of the all process is short. The foreground elements getting from the map can reflect the characteristics of the map's space and color. It is accurate and keeps the form of the line very well. Experiments prove that running speed and the result are satisfied.