Essay On Watermarking

III. WATERMARKING PROPERTIES AND REQUIREMENT
1. Perceptual resemblance
This characteristic also known as imperceptibility or visual similarity, which is considered one of the main important properties of any watermarked media. It means that the visual content of the original media and the watermarked media are identical in their visual form, each one is similar to the other, and the perceptual contents for both media is identical. For the watermarks used for copyright and content authentication, it’s very important that that the watermark cannot be detected or noticeable by the viewer, it’s only detected by an authorize users through special processing. One more thing, the watermark should not degrade the quality of the content of these digital media.
2. Blindness (Oblivious)
In digital watermarking, the term blindness is used to define the detection and extraction processes. The degree of blindness helps in characterize the watermark into blind, non-blind or semi blind. Digital watermarking technique is said to be blind if it doesn’t need the original media to recover the watermark from the watermarked media, the watermarking technique known as non-blind technique, if it is require the original media for extracting the watermark from the watermarked media. The

Security of watermarking means that it should be very difficult to alter or remove the watermark without destruct or harm the host signal. Security can be regarded as the capability to secrecy and integrity of watermark information, and as a resistance against malicious attacks. Generally, a watermark system considered as a secure, if the attacker cannot remove the watermark without possessing all the required information about the embedding algorithms, detection and extraction processes and the structure of watermark. The watermark must be only be accessible by authorized