2D Vector Map Fragile Watermarking with RST Invariance and Region Location

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Abstract

For 2D vector map fragile watermarking, tolerating RST (rotation, scaling and translation) operations and locating all tampered regions at the same time is a challenging task. In this paper, we propose a fragile watermarking method that not only tolerates RST operations, but also locates all tampered regions. The method divides the features of the vector map into groups. For each group, a watermark that is composed of location-bits and check-bits is generated. The location-bits are generated to locate the RST version of the group’s original region, while the check-bits are formed to be invariant to RST operations and sensitive to malicious attacks. Using a RST invariant data hiding method, the check-bits are embedded into the group itself, and the location-bits are embedded into its mapping group. If a watermarked vector map has suffered from malicious attacks and RST operations during transmission, all the tampered groups’ current regions and the RST version of their original regions can be located. Experimental results are provided to demonstrate the effectiveness of our method.