DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [1] AN ANALYSIS OF DIGITAL WATERMARKING IN FREQUENCY DOMAIN Presented by SRINIVAS KHARSADA PATNAIK ROLL # EI Under the Guidance of DR. SAROJ KUMAR MEHER Faculty in Electronics & Communication Engineering

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [2] DIGITAL WATERMARKING  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.

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [3] REQUIREMENTS  Perceptual transparency  Robustness  Security  Payload of watermark  Oblivious and non-oblivious

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [4] FREQUENCY DOMAIN WATERMARKING  First transformed to frequency domain.  Low frequency components are modified to contain text or signal.  DCT  DFT  DWT  STFT

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [5] BLOCK DIAGRAM REPRESENTATION

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [6]  Two techniques for embedding  Additive  multiplicative  I=original image, W=watermark, I’=watermarked image, a=scaling factor.

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [7] DISCRETE COSINE TRANSFORM  Real domain transform  Represents image as coefficient of different frequencies of cosines.  Forms the basis of the JPEG image compression algorithm.  Watermark  detection  embedding  casting

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [8] DISCRETE FOURIER TRANSFORM  Translation invariant  Modulated DFT amplitude coefficients  Makes watermark image content dependent

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [9] DISCRETE WAVELET TRANSFORM  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

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [10] SHORT TIME FOURIER TRANSFORM  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.

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [11] APPLICATIONS  Copyright protection  Fingerprinting  Copy protection  Broadcast monitoring  Indexing  Medical safety

DIGITAL WATERMARKING SRINIVAS KHARSADA PATNAIK [12] CONCLUSION  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.