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This paper proposes a watermarking scheme that serves the purposes of both copyright protection and tamper detection. Different from other schemes that use one piece of watermark information for one purpose and another different piece for the other, the watermark information used for copyright protection is also utilized for tamper detection in the proposed scheme. Moreover, unlike other schemes that employ a fixed strength value for embedding watermarks, the proposed scheme utilizes two different values, one for flat regions and the other for complex regions. As a result, the robustness of the watermark is improved with little sacrifice in image quality. The experimental results demonstrate the robustness of the proposed scheme for copyright protection as well as the effectiveness for tamper detection.

This paper proposed a novel copyright protection scheme for color images using image secret sharing, just-noticeable-distortion (JND) model and wavelet transform. The scheme contains two phases: the watermark embedding phase and the watermark extracting phase. In the watermark embedding phase, the color space of the color host image is first converted from RGB to YCbCr. Then a special sampling plane is created from the YCbCr color space. Next, the discrete wavelet transform is used to extract the features from the sampling plane. Then, a principal share image is generated according to the features and the watermark. Finally, the JND value and the discrete wavelet transform are used to embed the principal share image in the color host image to generate the watermarked image. In the watermark extracting phase, the principal share image is first retrieved from the suspect image. Then, an expanded watermark is reconstructed using the features of the suspect image and the retrieved principal share image. Finally, the recovered watermark is obtained after the reduction of the expanded watermark. The recovered watermark is then verified against the original watermark to examine the copyright. The experimental results show that the proposed scheme can resist several attacks such as cropping, blurring, sharpening, scaling, JPEG compression, brightness adjustment, and contrast adjustment.

This paper considers weather satellite images as the protected host images and proposes a novel copyright protection scheme according to the property of the images. The scheme contains two phases: the share image generation phase and the watermark retrieval phase. In the generation phase, the proposed scheme first generates a cloud image from the host image using gray-level slicing and creates a special sampling plane image from the cloud image and the host image. Next, the scheme extracts the features from the sampling plane image using the discrete wavelet transform. Then, the scheme employs the features and the watermark to generate a principal share image. In the retrieval phase, an expanded watermark is first reconstructed using the features of the suspect image and the principal share image. Next, the scheme reduces the additional noise to obtain the recovered watermark, which is then verified against the original watermark to examine the copyright. The experimental results show that the proposed scheme can resist several attacks such as JPEG compression, blurring, sharpening, scaling, and cropping.

This paper proposes a copyright protection scheme using human fingerprint images as watermarks. The scheme includes the feature extraction of the fingerprint image and the generation of the share image used to retrieve the fingerprint image. If an unauthorized copy is found later, the origin of the copy can be determined by the retrieved fingerprint image. Fingerprint image enhancement technique is employed prior to feature extraction to obtain a more reliable estimation of feature locations. In addition, the paper employs correction to reform the quality of the fingerprint image. According to the experimental results, the acceptance rate is up to 99% under several severe conditions. The experimental results also show that the scheme can tolerate several image processing attacks on the host image.