Digital watermarking algorithm of vector map based on feature points

In this paper a digital watermarking algorithm of vector map based on feature points is proposed. Here the complex wavelet transform is employed to process the vector map. In order to get complementary effects against different attacks of image processing operations, feature points of vector map need to be first extracted, and then construct the complex form of feature points coordinates into complex numbers sequence, to which two level DTCWT is applied. Watermark information is later embedded into the transformed high and low-frequency parts. Experimental results show this algorithm possesses a relatively high level of anti-attack capacity against operations such as translation, scaling, compression, noises.