Spread spectrum wavelet watermarking system

Lately attention has been focused on wavelet-based watermarking because of its compatibility with the newly developed JPEG 2000 image compression scheme. The major setback associated with wavelet-based watermarking is its vulnerability to geometric distortion caused by the lack of invariance property of wavelet transform. The domain of digital watermarking focused on spread spectrum based technique because of its excellent antijamming feature in wireless communication. However existing digital watermarking systems based on spread spectrum technique are yet to replay the anti-jamming feature in wireless communication, hence have not yielded the desired fully robust characteristics. Existing geometric invariant spread spectrum watermarking systems are complex, difficult to implement and unreliable. In our view this is due to inability of researchers to faithfully implement spread spectrum principle. Our investigation showed that most spread spectrum based watermarking faithfully implement the embedding process but fail to despread the signal before detection as required in a typical wireless spread spectrum communication. In this project we propose a simple spread spectrum wavelet watermarking system that is secure, tuneable and fully robust to all known forms and severities of attacks. The novel feature of our watermarking system design is its model as a communication system with the original (host) image representing the communication channel, the watermark represent the message (base band) signal and the legal and malicious attacks represent the noise, interference or jamming of the message signal. Experimental results from our system showed a replay of the excellent anti-jamming feature of spread spectrum communication technique and confirm the superior performance of our system over existing correlation-based spread spectrum wavelet watermarking system