earticle

영어

The paper proposes a novel scheme for watermarking color images. Majority of the papers published on color image watermarking consider color image watermarking process as a normal extension to grayscale image watermarking techniques without attending to the specific characteristics of color images. In color image watermarking, the host color image is embedded using a unique mark with the sole intention of making the host image identifiable. The objective of this work is to find suitable regions in a color image where the watermark embedding could be effected robustly without significantly degrading the image and at same time ensuring the impact of embedding will remain imperceptible. The proposed algorithm uses Discrete Cosine Transform to transform the host image into frequency domain for selecting appropriate coefficients for watermark embedding. Also, instead of resorting to global embedding of watermark over host image, safer regions that are oblivious to watermark embedding are selected for watermark integration. The measures discussed ensures that the watermarking process do not introduce visible distortions. A new metric, named as GEI (Global Embedding Impact), is also defined for measuring the impact of embedded watermark information over each host image pixel.