Research And Realization On Raster To Vector

Raster to vector conversion is the current hot area on graphics and image processing; the research on this technology is of great significance on theory and practice. After having studied the recent representative methods, the paper does improvements combined with the actual situation, and eventually realizes a simple vectorization system.The current prevalent vectorization method based on thinning algorithm is adopted in the paper. Firstly, the gray image is transformed into binary image by maximal difference between two classes. Then words label in the binary image are separated from image by enveloping rectangle algorithm. In the process of thinning, a new thinning method keeping inner pixels and deleting outer pixels is put forward. Compared with the traditional thinning algorithm, the skeletons of the objects produced by this algorithm are single-pixel wide, and can completely preserving the connectedness of the original image.For the single-pixel skeletons getting from thinning, a global vectorization algorithm based on node area is proposed in this paper. Firstly, the nose area is abstracted. Then the topology information was improved in the process of connected segment tracing, and the connected segment is transformed into its vector form by shorted-distance method. Lastly, the vector segment is combined according to the topology information and the longest expended principle, also can be called graphics reconstruction. At the same time the final vector graphics is got. In the processing of connected segment tracing, if the pixel has been deal with the one can be deleted. This method effectively prevents the repeated treatment to pixel, and reduces the complexity, so the speed is improved. An adaptive node regulation algorithm is adopted before graphics reconstruction that has greatly improved the distortion in node area and improved the accuracy of the vector.The vectorization system in this paper realizes the interface with Lion King Soft, which is a kind of GIS software. It has certain significant and application value.