What is Digital Watermark?
The definition of digital watermark
Digital watermark also referred to as simply
digital watermarking, a pattern of bits inserted into a digital image watermark, audio
digital watermarks or video digital watermarks file that identifies the file's copyright information (author, copyrights, etc.). The name comes from the faintly visible
digital watermark imprinted on stationery that identify the manufacturer of the stationery. The purpose of watermark is to provide copyright protection for intellectual property that's in digital format.
The technology of digital watermark
Unlike printed watermark, which are intended to be somewhat visible,
digital watermarks are designed to be completely invisible, or in the case of audio clips, inaudible. Moreover, the actual bits representing the digital watermark must be scattered throughout the file in such a way that they cannot be identified and manipulated. And finally, the
digital watermark must be robust enough so that it can withstand normal changes to the file (Removing digital watermarks), such as reductions from lossy compression algorithms.
Satisfying all these requirements of digital watermark is no easy feat, but there are a number of companies offering competing technologies. All of them work by making the digital watermark appear as noise - that is, random data that exists in most digital files anyway. To view a digital watermark, you need a special program that knows how to extract the
digital watermark data.
Watermark for digital image
Here we wanna say
the connection between watermark and image, a visible watermark on image. In most, we have no those special programs, and we never know how to get those programs, we just want to put watermark on our digital images. We need protect our online photo's copyright to avert illegal copy and downloading, that is what we want.