A Strategy for Opposing DC Components Watermarking

For the watermarking technique, which embeds the watermark in the dc components of the discrete cosine transform (DCT) based image using the method presented by Huang et al. (1), we present two methods to remove the watermark from the carrier image. In our first method, it removes the watermark via varying the energies in the transform domain and redeeming the luminance in the spatial domain. And in the second method, it removes the watermark through diversifying the intensity of dc components in the transform domain. These two methods both can remove the watermark and pass the watermark detection as the images without hidden watermarks. In addition, though we remove the watermark from the watermarked image, the peak signal-to-noise ratio (PSNR) of the cleaned image, in comparison with the original carrier image, is still high.