Very fast watermarking by reversible contrast mapping

Understand

Reversible contrast mapping (RCM) is a simple integer transform that applies to pairs of pixels.

• For some pairs of pixels, RCM is invertible, even if the least significant bits (LSBs) of the transformed pixels are lost.
• The data space occupied by the LSBs is suitable for data hiding.
• The embedded information bit-rates of the proposed spatial domain reversible watermarking scheme are close to the highest bit-rates reported so far.