Prepared for DA 201  Introduction to Digital Watermarking

What is a watermark?  Originally developed…end of 13 th 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  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)