Colour image watermarking for tamper proofing and pattern based recovery
The rapid development of the internet allows digital media being easily delivered, copied and even tampered. The watermarking issue has thus focused mainly on the medium of authentication. In this study, an efficient self embedding watermarking scheme for colour image authentication is proposed. The scheme is designed to achieve tamper proofing and high quality recovery. The scheme is efficient because the validity of image blocks is simply proofed by using a dual option parity check method and morphological operations. The former is used to generate authentication information for obtaining better results of tamper proofing and the latter is used to further improve the neighbouring connectivity of the proofing results. To achieve high quality recovery of the tampered image, the feature information of the host colour image and its corresponding block edge pattern information are properly organised to embed into three colour components of the host colour image. Meanwhile, the embedding information is appropriately distributed over luminance and chrominance components of the colour image in the YCbCr colour space such that the quality of the watermarked image can be better obtained. The simulation results show that the proposed watermarking scheme can effectively proof the tempered region with high detection rate and can restore the tempered region with high quality.