Data hiding has drawn increasingly extensive attention recently. Most multimedia data hiding techniques

modify and, hence, distort the cover media in order to insert the additional information. Even though the

distortion is often small and imperceptible to human visual systems (HVS), the original cover media usually

cannot be restored completely. In other words, they are noninvertible data hiding, which is not admissible to

some sensitive applications, such as legal and medical imaging. For these applications, reversible data hiding

is desired to extract the embedded data as well as to recover the original host signal. Reversible (also often

referred to as lossless, invertible , or distortion-free) data hiding has been a very active research subject in the

last a few year-Data hiding has drawn increasingly extensive attention recently. Most multimedia data hiding techniques

modify and, hence, distort the cover media in order to insert the additional information. Even though the

distortion is often small and imperceptible to human visual systems (HVS), the original cover media usually

cannot be restored completely. In other words, they are noninvertible data hiding, which is not admissible to

some sensitive applications, such as legal and medical imaging. For these applications,　reversible　data hiding

is desired to extract the embedded data as well as to recover the original host signal. Reversible (also often

referred to as lossless,　invertible , or distortion-free) data hiding has been a very active research subject in the

last a few year