A reversible watermarking scheme for 2D engineering graphics based on improved quantisation index modulation

Due to its inherent limitations, the conventional quantisation index modulation (QIM) cannot be applied to reversible watermarking directly. An improvement is done in this work to QIM to make it suitable for reversible watermarking. Based on the improved QIM (IQIM), a reversible watermarking scheme for 2D engineering graphics is proposed. The relative amplitudes and relative phases of entity vertices are used as hosts to carry the watermark. Experimental results indicate that they can strike a good balance between capacity, imperceptibility, robustness, security and complexity.