Download to read offline
Uploaded byDeepak Singh
Presentation
This presentation provides an overview of watermarking, including its historical background and classifications. Watermarks can be fragile, robust, or semi-fragile depending on their ability to withstand modifications. Examples of watermarking applications include text, images, audio, and video. Watermarking can be used for copyright protection, tamper detection, authentication, and tracing the origin of illegal copies. However, watermarks are vulnerable if the encoding key is lost or made public.
Presentation
- 1. Presentation on Watermarking Presented By Deepak Singh (1009131031) Supervised By V L Swarup + N Suvarna
- 2. Outlines • Historical background • Classifications • Characteristics • Examples • Applications • Problems • Bibliography
- 3. Steganography Art of hiding information • Initial Applications of information hiding to Pass Secret messages. • Histaeus used his slaves (information tattooed on a slave’s shaved head )
- 4. Cryptography • Study of techniques for secure • German Lorenz cipher machine, used communication in the presence of in World WarII to encrypt very-high- third parties level general staff messages
- 6. Cryptography(cont) The Greeks ofClassical times are said to have known of ciphers (e.g., the scytale transposition cipher claimed to have been used by the Spartan military)
- 7. Watermarking • Technique forinserting information into another information (text,image,video) which can be later extracted or detected for variety of purposes including identification and authentication purposes
- 8. Example of watermarkedslide Originality of hardcopy is ensured
- 9.
- 11. Characteristics of awatermark Fragile: Distorted or broken under slight changes Used for tamper detection. Robust: withstand moderate to severe signal processing attacks . used for copyright protection and to verify the ownership. Semi-fragile: features of both robust and fragile. Sensitive to modification and provides authentication.
- 12. Text Watermarking • Text-linecoding Text lines of a document page are shifted imperceptibly up or down Word-shift coding Spacing between words in a line text is altered Character coding E.g., endline at the top of a letter, say “t” is feature coding; slightly modifies the features extended Goal: making watermark removal more expensive than obtaining the right to copy from the copy right owner
- 13.
- 15. • Softwares 1:-Digital image security evaluation. 2:-TSR Watermark Image software 2.3.3.4 . (applicable on pictures,images)
- 16. Audio Watermarking Spread spectrum audio watermarking (SSW) • Narrow-band message signal is transmitted over a much larger bandwidth So watermark is spread over many frequency bins so that the energy in one bin is very small and certainly undetectable. • Audio watermarks won't survive compression to a format like MP3 or WMA or M4A, which is one reason they aren't used very much.
- 17. Video Watermarking • placing a digital watermark or logo or text over an existing video in the batch mode. • Watermarks can be used for adding comments to your movies. • Research is going on.
- 18. Applications Tamper proofing: Tofind out if data was tampered. Eg. Change meaning of images Hidden Watermarks track change in meaning
- 19. Applications Copyright Protecton:Toprove the ownership of digital media Eg. Cut paste of images Hidden Watermarks represent the copyright information
- 20. Applications Quality Assessment:Degradation of Visual Quality Loss of Visual Quality Hidden Watermarks track change in visual quality
- 21. Applications • Fingerprinting:- Owner can embed a robust watermark that identifies the buyer of the copy .If unauthorized copies are found later, origin of the illegal copies can be traced. • Authentication:- Owner can embed fragile watermark to provide proof of authenticity and integrity. Tampering destroys fragile watermark and thus can be detected
- 22. • Ownership assertion:- A rightful owner can retrieve a watermark from his content to prove his ownership
- 23. Problems • In casethe key used during watermark is lost anyone can read the watermark and remove it. • In case the watermark or key is public, it can be encoded and copyright information is lost.
- 24. Bibliography • http://en.wikipedia.org/wiki/Watermark • http://en.wikipedia.org/wiki/Digital_watermarking •http://www.videowatermarkfactory.com/
- 25.