2D vector map data hiding with directional relations preservation between points

Several 2D vector map reversible data hiding schemes presented in the literature are not capable of preserving the directional relations between map objects. This weakness may lead to the exposure of the camouflaged secret data to unauthorized parties and attract malicious attacks. In this paper, we propose a method that preserves the directional relations between points in 2D vector maps while sustaining the original content recovery property of reversible data hiding schemes. In particular, we propose sorting the coordinates of each axis, separating the sorted coordinate lists into segments, adding two boundary coordinates to each segment, and embedding data into eligible intervals. While the selection of eligible intervals ensures directional relations preservation between points, the segment division and the addition of boundary coordinates provide good invisibility and high capacity. We provide experimental results to demonstrate the effectiveness of our method.