OBJECTIVE To provide authenticity or the identity of ownership on images. Protecting digital images against un-authorized use, i.e. duplication, mis-representation and mis- distribution or illegal usage. main focus is to embed a color watermark image in to a color host image.
Introduction Digital watermarking The process of embedding digital information into a digital signal. - Purpose - Various types of Watermarking - Basic requirements Invisible Fragile Image Watermarking. Embed a color watermark image in a color Host Image.
Requirements : The extracted watermark remains intact. i.e., image authentication is guaranteed. Quality of generated watermarked image should improved. w.r.t. others. The security issues related to the watermark are provided using a secret key and a hash function.
Ideal Properties perceptually invisible to prevent obstruction of original image. statistically invisible, so it can’t be detected or erased. extraction should be simple and accurate. the watermark should be able to determine the true ownership of the Image.
Features: Transparency : Perceptual quality of data being protected. Robustness : with stand against any intentional transformations. Capacity : the ability to detect the watermarks with a low probability of error.
Process: Host image is divided in to some blocks. Embed watermark at LSB of Blue values of all such blocks . Manipulating only the ‘Blue values’(HVS). No. of host image blocks should be equal to the no. of bit embedded multiplied by the bit size of RGB.
Observation : We can easily see that Ai= Ai. So our watermark image is retained intact (complete) after extraction, by combining all bit-planes from all blocks.Advantages: Security Persistency of Image Quality At the time of extraction neither the host image nor the watermark image is needed. Copyright Protection Tamper Proof verification
CONCLUSION AND FUTURE SCOPE Among large variety of watermarking techniques, an attempt has been made to develop color image watermarking scheme for color images. Both host image and watermark images are color images. The extracted watermark remains intact, i.e. image authentication is guaranteed. As a future research scope attempt will be make to develop the framework to semi-fragile watermarking, to detect malicious manipulations on an image, while allowing acceptable manipulations.