What is digital marking and what, are the types of digital watermarking? What can be the application of digital marking and what, are digital watermarking techniques?
As we know both cryptography and steganography provides secret communication. But they are not the same. Cryptography hides the secret content where steganography will not even let you know that there exists some secret message. A new technology called digital watermark contains both theories. It hides the copy write information into digital data with the help of several algorithms. The watermark can be hidden in the digital data, either visibly or invisibly.
There are six types of digital watermarking: fragile, robust, reversible, perceptible, imperceptible, and data watermark.
Digital watermarking is useful in many applications including broadcast monitoring, transaction tracking, content authentication, ownership assertion, copy control, and fingerprinting.
There are two techniques of digital watermarking:
Frequency domain watermarking technique: Compared to the spatial-domain method, the frequency domain method is more used. The main aim of this technique is to embed the watermark in the spectral coefficient of image. It makes use of Fourier transform, cosine transform, discrete cosine transform.
Spatial domain watermarking technique: this technique represents the image in the form of pixels. It embeds the watermark by modifying the intensity of the color value of the pixels. It is more easygoing than the frequency domain watermarking technique.
