Robust Colour Image Watermarking Scheme Based on Feature Points and Image Normalization in Dct Domain

Geometric attacks can desynchronize the location of the watermark and hence cause incorrect watermark detection. This paper presents a robust colour image watermarking scheme based on visually significant feature points and image normalization technique. The feature points are used as synchronization marks between watermark embedding and detection. The watermark is embedded into the non overlapped normalized circular regions in the luminance component or the blue component of a color image. The embedding of the watermark is carried out by modifying the DCT coefficients values in selected blocks. The original unmarked image is not required for watermark extraction Experimental results show that the proposed scheme successfully makes the watermark perceptually invisible as well as robust to common signal processing and geometric attacks.