A visible watermark should be obvious in both color
and monochrome images.
The watermark should spread in large and important
area of image in order to prevent its deletion by
clipping.
The watermark should be visible yet must not
significantly obscure the image details beneath it.
The watermark must be difficult to remove.
Removing watermark should be more costly and
labour intensive than purchasing the image from the
owner. The watermark can be applied automatically
with little human intervention and labour.
Watermarking is the process that embeds data called
watermark or digital signature or tag or label in to
multimedia object. The object may be image, audio or
video.
Any watermarking scheme or algorithm consist of three
parts 1. Watermark 2. The encoder ( insertion algorithm) 3.
The decoder and comparator( verification algorithm)