digital water marking
DESCRIPTION
TRANSCRIPT
Digital Watermarking
Introduction
Types of Digital Watermarking
Working Domain
Human Perspective
Types of Documents
Presentation Outline
Application
Introduction Digital Watermarking Technology
• Allows - Embed Data - Digital Signals
• Secret Message - Embedded - Cover message
• Difficult to Remove
• Knowledge - Secret Key – Allow - Extract • Text, Still Images,Video or Audio Data
• Watermarking - Protect Copyright - Original Owner
• Identification & Authentication
Types of Digital Watermarking
Types Of Documentation
Types Of Documentation
Types of Digital Watermarking
• MP3Stego: WAV -> MPEG-3 + additional Data
• Temporal masking
– 5-20ms before a loud signal
– 50-200ms after a loud signal
Types Of Documentation
Types Of Documentation
Types of Digital Watermarking
Types of Digital Watermarking
Watermarking life-cycle phases
Steps in Watermarking• Embedding Information embedded - digital watermark
Signal where the watermark - embedded - host signal
In embedding, an algorithm accepts host & data - embedded & produces a watermarked signal.
• Attack During transmission, If this person – modification - called attack.
• DetectionAlgorithm applied - attacked or unmodified signal - attempt extract watermark
Working DomainSpatial Domain
• Methods use block x block based watermarking.
• e.g. embed watermarks - randomly selected 8x8 blocks pixels - image.
Frequency domain
• Embed a watermark, frequency transformation - applied - host data
• Modifications - transform coefficients
• Possible frequency image transformations - Discrete Fourier Transform
Human Perspective
Visible watermark:
Information visible - text or logo - identifies - owner - media.
Human Perspective
Invisible watermark:
Invisible watermark - embedded image - cannot be perceived - human’s eyes
Intended -prevent or deter unauthorized copying - digital media.
Invisible Watermarking
Visible Watermarking
A watermark may be:
Fragile: distorted or broken under slight changes
Semi-fragile: designed - break under all changes - exceed
user- specified threshold
Robust: withstand moderate - severe signal processing attacks (compression,rescaling,filtering)
Application1. Copyright protection
• Most prominent application• Embed information - owner - prevent others - claiming copyright• Require very high level of robustness
2. Copy protection
• Embed watermark - disallow unauthorized copying - cover• E.x. compliant DVD player - not playback or copy data - carry “copy
never” watermark
3. Content Authentication
• Embed watermark - detect modifications - cover• Watermark - low robustness, “fragile”
Application4. Transaction Tracking
• Embed watermark - convey information - legal recipient – cover
• Useful - monitor or trace back illegally produced copies – cover
• Referred as “fingerprinting”
5. Broadcast Monitoring
• Embed watermark - cover & use automatic
• Monitoring - verify whether cover - broadcasted as agreed
Conclusion
Digital watermarking focuses on embedding information inside a digital object such that the embedded information is in separable bound to the object.
References
• www.google.com
• www.wikipedia.org
• www.scribd.com
• www.clic2c.com
• www.youtube.com