13-09-2013, 04:56 PM
A Robust Image Watermarking Using Two Level DCT And Wavelet Packet Denoising
Robust Image Watermarking.pptx (Size: 226.74 KB / Downloads: 27)
INTRODUCTION
In this application our aim is to develop a watermarking algorithm based on DCT and Spread spectrum communications.
To provide highly robust with respect jpeg compression and also other common attacks whenever they are applied to watermarked image.
Watermarking v.s. Steganography
Watermark messages contain information related the cover work
In steganographic systems, the very existence of the message is kept secret.
If the message tattooed on the slave is “the slave belongs to somebody”, then we can regard it as an example of watermarking
What is a watermark?
Water marking is one of the data hiding technique for security purpose.
This technique is proposed to protect copyright of digital multimedia data.
Watermarking is an important mechanism applied to physical objects like bills, papers, garment labels, product packing…
Water Marking Algorithms
Watermark embedding in many domains such as spatial and Fourier transform like DCT and DWT. One of the commonly used is DCT.
Most of watermarking schemes employ mainly frequency domain approach because it is superior to the spatial domain in robustness and stability.
Discrete Cosine Transform(DCT)
DCT splits up the image into frequency bands, similar to discrete Fourier transform, it transforms a signal or image from the spatial domain to the frequency domain.
For Example: Watermark was a sequence of 1000 random numbers. Watermark was embedded in the 1000 largest DCT coefficients. Correlation based non-blind detection were performed.