An Improved Blind Color Image Watermarking using DCT in RGB Color Space

In this paper a novel blind watermarking technique for color images using DCT has been proposed. Inproposed technique cover image is decomposed into 3 planes, namely R, G, B and for watermarking B plane is selected. B plane is divided into blocks of size 8×8. DCT is applied to each 8×8 sized block and middle frequency coefficients are selected for embedding watermark. Finally binary watermark is embedded into each8×8DCT block by adjusting middle frequency coefficients DCT(4,3) and DCT(5,2). Experimental results shows that the proposed technique is imperceptible as well as robust against wide variety of attacks like Gaussian noise, Salt –pepper noise, Gaussian filter, Median filter, Histogram equalization etc and achieves average PSNR as 58.90 dB. Proposed technique does not require cover image at the time of watermark extraction then too watermark is extracted completely and better than its counterparts available. General Terms Image Processing, Digital Watermarking,Watermark Embedding, Watermark Extracting