Artificial bee colony optimized robust-reversible image watermarking

摘要

The ownership verification of digital images is possible by the help of image watermarking. Watermarking make the image secure towards unlawful use; but at the same time, it causes some information loss too. Medical and defense are few fields, where even a small change in data can be very problematic. So there is need of reliable and lossless watermarking schemes. The present study is focused on the development of lossless watermarking method that can fulfill five basic requirements (robustness, reversibility, invisibility, security and capacity) of ideal lossless watermarking scheme maximally. Arnold transformed watermark is embedded into the host to restrict any unauthorized access of watermark even after extraction. Slantlet transformed coefficients are known to be quite robust towards image processing attacks; so block wise Slantlet transform is employed to resist the maximum attacks and to ensure a decent capacity. Mean values of transformed coefficients are used for embedding to increase the robustness and imperceptibility. The spatial domain overflow/underflow (due to embedding) is taken care by a post processing to satisfy the reversibility requirements. The embedding strength of watermarking is controlled with the help of artificial bee colony (ABC) in order to get an optimal tradeoff between invisibility and robustness. The proposed scheme is applied to a range of images to show its applicability to different domains.