19-01-2013, 02:42 PM
DIGITAL IMAGE WATERMARKING FOR SECURED COMMUNICATION
DIGITAL IMAGE WATERMARKING.pptx (Size: 697.82 KB / Downloads: 31)
NEEDS OF WATERMARKING:
Proof of Ownership (copyrights and IP protection)
Copying Prevention
Broadcast Monitoring
Authentication
Data hiding
DWT Based Invisible Image Watermarking Algorithm for Color Images
This used two stages
Embedding stage
Extracting stage
In order to watermark the image it uses the Discrete Wavelet Transform(DWT)
The RGB image is converted to HSV and watermarked by using discrete wavelet transform.
Watermarking embedded stage and extraction stage is designed using low power invisible watermarking algorithm.
Here the host signal is an image and after embedding the secret data a watermarked image is obtained and then extracts secret image and original image separately.
Robust Dynamic Block-Based Image Watermarking in DWT Domain
In this paper, a robust watermarking scheme in DWT domain is proposed.
We embedded the watermark into the significant wavelet coefficients in those dynamic blocks with strong edges according to “Binary Algorithm”.
Since the change to the blocks with strong edge strength is less visible to human eyes.
In this implementation the edge dynamic blocks are identified using a “Binary Algorithm”, for this reason variation of its threshold is influencing the
quality and accuracy of the extracted watermark.
The proposed method is suitable for maps and natural images that
have better edges.
In this section, some experimental results are demonstrated to show the effectiveness of the proposed watermarking scheme.
In order to test the performance of the proposed method we choose a binary watermark image of size 8×8.
CHARACTERISTICS
Invisibility : An embedded watermark is not visible.
Robustness : Piracy attack or image processing should not affect the embedded watermark.
Readability : A watermark should convey as much information as possible. A watermark should be statistically undetectable.
Security : A watermark should be secret and must be undetectable by an unauthorized user in general.
LIMITATIONS
The larger amount of information stored on a digital watermark, results in a more distorted picture.
Copyright owners may move or assign their ownership interest to another party.
Some companies are offering their digital watermarking software at no charge and thus make some of their profit by charging annual fees to copyright owners for maintenance of on-line current contact information.
not all watermarking techniques will be useful in resolving ownership disputes in courts of law