A novel image watermarking scheme using blocks coefficient in DHT domain

Copyright protection of digital media becomes a major problem in internet due to its nature which allows gross duplication, alteration or even stolen of data. Several watermarking methods are reported in recent years to protect copyright of digital images. A good watermarking algorithm must satisfy imperceptibility, robustness and high data hiding capacity but without compromising for any of them. In this paper a novel blind watermarking scheme in Hadamard transform domain for digital image is proposed. For embedding watermark bits we modify the DHT coefficient of two adjacent blocks in same position. Watermark is a string of characters. This algorithm offers advantages of simpler implementation, low computation cost and high resiliency under compression. The experimental results and performance analysis shows good robustness under JPEG image compression and other common image processing operations like cropping, rotation, noise addition and filtering.