PRESENTED BY, C.RESHMA –II CSE S.POORNIMA –II IT

 watermarking is to protect one’s work from being hijacked.  It also deals with various types of Watermark attacks.  When unauthorized copies or forgeries of the image appear elsewhere on the network, the designer needs to prove his ownership of the image.

 Imperceptible: The watermark should be imperceptible so as not to affect the viewing experience of the image or the quality of the audio signal.  Undetectable: The watermark must be difficult or even impossible to remove by a malicious cracker, at least without obviously degrading the host signal.

 Statistically undetectable: A pirate should not be able to detect the watermark by comparing several watermarked signals belonging to the same author  Unambiguous: Retrieval of the watermark should unambiguously identify the owner, and the accuracy of identification should degrade gradually in the face of attacks.

 Visible  Fragile  Spatial  Image –adaptive  Blind  Public & private  Asymmetric&symmetri watermarking  Steganographic&non-stenographic  Image watermarking

 Watermarking can be applied in the frequency domain by first applying a transform like the Fast Fourier Transform (FFT), Discrete Cosine Transform (DCT), Wavelet Transform etc.  hi gh frequencies will be lost by compression or scaling, the watermark signal is applied to lower frequencies  frequencies that contain important information of the original picture

 Frequency methods encode the data across the global frequencies of the image. Two types of information hiding methods are  Fast Fourier Transform (FFT)  Discrete Cosine Transform (DCT)

FFT ISOLAT FFT +  This transformation is one that converts the time domain signal into a signal of frequency domain IFFT OUTPUT WATERMARK

 Start the process.  Get the text data to a binary row vector.  Convert the text data to a binary row vector.  Scale the binary vector.  Create the data mark.  Compute the FFT and decompose into the magnitude and phase.  Create the ring of the data mark (using loops).  Add the ring to the magnitude of the image.

 Reduce the magnitude points where the data bit is zero. Convert the matrix into an image (i.e. watermarked image). Output the watermarked image. Stop the process.

APPLICATION:  Audio watermarking  Text watermarking  Fingerprinting Common attack techniques:  Additive noise  Cropping  Rotation & Scaling

 Digital watermarking is an effective technique for protecting intellectual property (IP)  It bears a huge commercial potential, used in consumer electronic devices.  Digital watermark technology can be used in consumer electronic devices such as digital still cameras, digital video cameras, set top boxes, DVD players, and MP3 players.  As a result it can protect information in controlled axes, prevent illegal replication and embedding ownership information in images captured in digital cameras.

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