A Recoverable Semi-fragile Watermarking Scheme Using Cosine Transform and Adaptive Median Filter

The paper proposes a novel semi-fragile watermarking scheme capable of detecting and recovering tampered regions to protect the integrity of images. The proposed scheme generates the features from the host image itself and uses them as the watermark, which is then embedded into the frequency domain of the host image. Additionally, the scheme uses an adaptive median filter to distinguish between common image processing operations and malicious attacks so that it can react properly. Moreover, the scheme can locate tampered areas and recover these areas. According to the experimental results, the scheme is robust to common image processing operations, including JPEG compression, and is capable of detecting malicious attacks, such as counterfeiting.