The Watermark Embedding Method Of Maps Based On The Color Feature

Recently, with the development of multimedia and network communication, the delivery of information become"digitalized"and"neutralized."However, digital media information is easily to be copied, processed, published and transmitted. Thus the problem of the safety and the reality of digital information transmission appeared. Especially, the e-crimes have done great harm to the safety of a country and its economy. Thus the protection of the digital information becomes more and more important.The traditional encryption or digital signature can not protect the digital product completely. As a supplement to the traditional technology, digital watermarking technique attaches much importance to people. More and more people come to study digital watermarking technique and make it apply to many aspects of information safety.Digital watermarking has been developed in more and more fields. People studied all kinds of method of watermark embedding, but little work has been done to develop watermarking algorithms for the class of map. The Traditional embedding methods are not fit for map because there is information of road, architecture, city and photographic etc on it, and so as its big size. While using maps, we often crop the maps, not just using the whole maps. For example, when we look at the map of a certain city and area, we destroy maps of watermark embedding unconsciously. Thus, this paper deals with the basic concept and a new theory of digital watermarking of maps.The feature of maps is analyzed in the first part: they have large areas of homogeneous Pixels'value. We put forward that the watermark can be embedded into the pixels on the boundary of a certain color by altering the distance of the pixels on the boundary. The remarkable feature is sticking up to cropping. We have done a great deal of experiments to prove it. Tests show that the watermarks in our method weren't affected no matter how the maps of the embedded watermark were cropped. Experimental results show that the algorithm is feasible and robust for many different kinds of attacks.Finally, this method also achieved good results when applied to the test For embedding watermark into text.