an analysis of digital watermarking in frequency domain
DESCRIPTION
TRANSCRIPT
[1]
AN ANALYSIS OF DIGITAL WATERMARKING IN FREQUENCY
DOMAIN
Presented by
SRINIVAS KHARSADA PATNAIKROLL # EI200118043
Under the Guidance of
DR. SAROJ KUMAR MEHERFaculty in Electronics & Communication
Engineering
DIGITAL WATERMARKING[2]
Form of data hiding or steganography.
Hides the message, so cannot be seen.
Maintains privacy and protects data from other viewers like hackers.
It may include hiding of numbers, logo or signature in the form of signal, image or video.
REQUIREMENTS[3]
Perceptual transparency
Robustness
Security
Payload of watermark
Oblivious and non-oblivious
FREQUENCY DOMAIN WATERMARKING
[4]
First transformed to frequency domain.Low frequency components are modified
to contain text or signal. DCT DFT DWT STFT
BLOCK DIAGRAM REPRESENTATION
[5]
[6]Two techniques for embedding Additive multiplicative
I=original image, W=watermark, I’=watermarked image, a=scaling factor.
)**(' WIaII
DISCRETE COSINE TRANSFORM
[7]
Real domain transformRepresents image as coefficient of
different frequencies of cosines.Forms the basis of the JPEG image
compression algorithm. Watermark
detection embedding casting
DISCRETE FOURIER TRANSFORM
[8]
Translation invariant
Modulated DFT amplitude coefficients
Makes watermark image content
dependent
)),(1(|),(||),(| vuWkvuDFTvuWDFT
DISCRETE WAVELET TRANSFORM[9]
Used when a signal is being sampled like digital signal or image processing.
Provides sufficient information for both analysis and synthesis of signal.
Reduction in computation time.
Separates image into sub images
SHORT TIME FOURIER TRANSFORM
[10]
The signal is divided into small stationary segments.
Used to acquire frequency representation of the actual frames.
Precision determined by size of window.
Not a flexible approach.
APPLICATIONS[11]
Copyright protection
Fingerprinting
Copy protection
Broadcast monitoring
Indexing
Medical safety
CONCLUSION [12]
We can work for digital protection by the help of certain laws.
Time complexity of watermark signal can be enhanced by extending the length of watermark.
Can be used in any frequency domain that involves quantization and transformation.