Reversible watermarking using difference of virtual border for digital image protection

摘要

Image watermarking by difference expansion is a method to hide data in the image using the difference of two pixels. Reversible watermark has a feature that original image can be restored. The virtual border is a mirror of border line of the image. In this paper, we proposed the modified difference expansion watermarking using LSB replacement in the difference of virtual border. The payload is formed by image hashing using MD5. To inverse this watermarking is a simple work, read the last bit of the virtual border difference, then eliminate the virtual border to get original image. It doesn't need compression or saving the loss information. The proposed technique has proved a hiding for both greyscale and colour images, so it can be used to protect vary images like military or medical images.