A reversible visible watermarking scheme for compressed images

Visible Digital watermarking is a technique that embeds copyright information perceptibly within the image to prevent illicit use of multimedia content. There are numerous applications that require user authentication to make the original image content available. However, the reversible visible watermarking schemes found in literature today are susceptible to quantization errors induced by lossy images and are therefore not applicable for high quality multimedia communications applications. This paper presents a novel reversible watermarking scheme suitable for lossy compressed images. The proposed mechanism reversibly embeds the residual information packet, required to restore the watermarked region, in the quantized transform coefficients. Furthermore, the residual information packet is calculated based on the compressed image in order to suppress quantization errors. The experimental results clearly confirm the superiority of the proposed scheme for compressed images where Peak Signal-to-Noise Ratio (PSNR) gains of up to 3 dB were registered relative to the other state-of-the-art reversible watermarking schemes found in literature.