2,231 research outputs found
Copyright Protection of Color Imaging Using Robust-Encoded Watermarking
In this paper we present a robust-encoded watermarking method applied to color images for copyright protection, which presents robustness against several geometric and signal processing distortions. Trade-off between payload, robustness and imperceptibility is a very important aspect which has to be considered when a watermark algorithm is designed. In our proposed scheme, previously to be embedded into the image, the watermark signal is encoded using a convolutional encoder, which can perform forward error correction achieving better robustness performance. Then, the embedding process is carried out through the discrete cosine transform domain (DCT) of an image using the image normalization technique to accomplish robustness against geometric and signal processing distortions. The embedded watermark coded bits are extracted and decoded using the Viterbi algorithm. In order to determine the presence or absence of the watermark into the image we compute the bit error rate (BER) between the recovered and the original watermark data sequence. The quality of the watermarked image is measured using the well-known indices: Peak Signal to Noise Ratio (PSNR), Visual Information Fidelity (VIF) and Structural Similarity Index (SSIM). The color difference between the watermarked and original images is obtained by using the Normalized Color Difference (NCD) measure. The experimental results show that the proposed method provides good performance in terms of imperceptibility and robustness. The comparison among the proposed and previously reported methods based on different techniques is also provided
Perceptual Copyright Protection Using Multiresolution Wavelet-Based Watermarking And Fuzzy Logic
In this paper, an efficiently DWT-based watermarking technique is proposed to
embed signatures in images to attest the owner identification and discourage
the unauthorized copying. This paper deals with a fuzzy inference filter to
choose the larger entropy of coefficients to embed watermarks. Unlike most
previous watermarking frameworks which embedded watermarks in the larger
coefficients of inner coarser subbands, the proposed technique is based on
utilizing a context model and fuzzy inference filter by embedding watermarks in
the larger-entropy coefficients of coarser DWT subbands. The proposed
approaches allow us to embed adaptive casting degree of watermarks for
transparency and robustness to the general image-processing attacks such as
smoothing, sharpening, and JPEG compression. The approach has no need the
original host image to extract watermarks. Our schemes have been shown to
provide very good results in both image transparency and robustness.Comment: 13 pages, 7 figure
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