Prepared for DA 201 Introduction to Digital Watermarking.

Prepared for DA 201

Introduction to Digital Watermarking

What is a watermark?

Originally developed…end of 13th century

Used to differentiate paper makers of the time

Oftentimes a company logo overlaid on digital images used by photographers

Types of watermarking

Video watermarking

Image watermarking

Audio watermarking

How does it work?

Watermark can be digitally embedded in images

Done for copyright protection purposes

Central database of image digests is kept

Periodic searches of the www are done…for images having the same digest

Digital watermarking: provides a way to protect the rights of the owner of a file, the owner can prove it is his.

You can still see the image or document… can preview the image, but not use it until you purchase the rights to it.

Properties of digital Watermarking

-hides data in a file

-the act of hiding data makes it a form of steganography for protecting and proving ownership…not for transmitting info

- if watermark is removed…..image will be destroyed.

Digital Watermarking

When you apply a watermark to a file

You are modifying the file This is referred to as noise

Can it be seen?

Digital watermarking is imperceptible to human senses

Easily recognized by software or hardware detectors

DW remains constant through compression & decompression

Is it robust?

Digital Watermark remains constant through

encryption & decryption very effective for distributing

digital & analog media

Who uses Digital Watermarking? Photographers… to identify & manage

image copyrights

Movie studios…. to deter piracy of movies, music & DVDs

Record labels… to deter piracy

TV broadcasters…to track, verify & measure TV and radio programming & advertising

Corporations… to authenticate IDs and deter identity theft and fraud & document counterfeiting

Who uses digital watermarks? Satellite image providers……to identify

ownership & enhance the value of geospatial intelligence information

Enables media serialization of digital content….making identification of specific instances of content possible!!!

Sometimes watermark is embedded in audio signal…Serial Code Management (digital copy prohibited)

Why do they use it?

To identify Protect Manage the rights to content (IP)