A Low-Distortion Reversible Watermarking for 2D Engineering Graphics Based on Region Nesting

With the aim of reducing the distortion of traditional partitions, this paper investigates a novel method that partitions every square region into 2(n) nesting sub-regions. Based on the partition, a low-distortion reversible watermarking for 2D engineering graphics is proposed. The watermark is embedded by mapping the vertices in the original region to its corresponding sub-regions, and it is extracted according to the locations of the mapped vertices. Meanwhile, the original locations of the vertices can be restored by inverse mapping. Furthermore, by constructing a new coordinate system, the rotation, scaling, and translation semi-fragility of the watermarking can be achieved. Experimental results and analysis show that the proposed watermarking achieves good performance in terms of the capacity and semi-fragility, while the imperceptibility of the watermarking is significantly improved in comparison with the existing algorithms under the same conditions.