Threshold Dependent Data Embedding and Extracting Scheme Based on Pixel Pair Expansion Method

Digital watermark is a type of technology that embeds copyright information into digital image. Digital Watermarking works by hiding information inside digital data, such that it cannot be noticed without any software help with the purpose of building sure the covered data is present in all copies of the information that are completed whether legally or if not, in spite of efforts to scratch or eradicate it. Generally it is known that each watermark system consists of an embedding algorithm and an extracting algorithm. The embedding algorithm includes the watermark details in the data and the extracting algorithm decodes the watermark details. We have proposed a reversible embedding and extraction mechanism to embed data in an image which modify the embedded location in least significant bits. The algorithm has good embedding capacity along with preserving the original content of the image up to an acceptance level. This has been measured in terms of PSNR and MSE values which tell the degradation in watermarked image with respect to original image. The algorithm works in fully reversible domain in which there is no need of secret key as well as the original image as it uses only the watermarked image to extract the embedded bits in same sequence.