For 2D vector maps, obtaining high tamper localization accuracy without requiring extra space is a technically challenging problem. Using an adaptive group division approach and an improved reversible data hiding approach, the author proposes a reversible fragile watermarking method for locating tampered Polylines/Polygons in 2D vector maps. In particular, the author adaptively divide the features of the vector map into groups according to a predefined threshold, calculate an authentication watermark for each group, embed the watermark using the improved reversible data hiding approach, and hide the mark of each feature into the feature itself. Since the adaptive group division method and the improved reversible data hiding method are combined in an attempt to make full use of the watermark embedding space, superior tamper localization accuracy and original content recovery can be ensured. Besides, no extra space is required by hiding the mark of each feature. Experimental results have been provided to demonstrate the effectiveness of our method.
Robust and fragile watermarking for medical images using redundant residue number system and chaos