Lossless Information Hiding

In the recent years,the rapid development of computer information and the increased use of multimedia data via the Internet have resulted in the faster and more convenient exchange of digital information.On account of the ease of editing and perfect reproduction,it is important to prevent unauthorized manipulation of digital content. Information hiding,a technique to embed special labels in digital contents,has led to much research recelently.However,most information hiding methods introduce distortions to the original content,the embedding distortion is irreversible,it cannot be removed to recover the original host signal.But some other authentication applications such as medical imagery and military image prohibit the permanent loss of image fidelity during hiding.It is often desirable to embed the information in a reversible way—reversible information hiding.The reversible information hiding as a branch of information hiding technique can not only remove the hided information,but also get the copy of the original data without any loss.Firstly this paper looks back the development of the information hiding especially the reversible information hiding technique,the new methods on the basis of existing theories,and introduces those methods by the different hiding theories.secondly,this paper recommends the integer wavelet transform and it's application in the reversible data hiding.Lastly this paper emphasizes the reversible information hiding in the frequency domain.it also shows the releted knowledge such as histogram modification,disarrange technique,compression throughout the last part.In the frequency domain,we make the modification of histogram by the transform of integer wavelet corresponding in the spatial domain,then embed the data in the high coefficient,at last make the countertransform to finish the method.The method chooses six frequences,three high and three low to embed data after two transforms of integer wavelet.In order to show the excellence of this method we also give other two projects. The first one chooses the peak of three high frequences to hide the data after one integer wavelet transform;while the second one chooses three high frequences and one low frequence.The same algorithm is used in the same high frequence;however the method in the spatial domain is used in the low frequence.In the end the experimental results show the method in this paper can embed more information and have good visual quality according to the same peak siginal-to-noise, especially the method has good result in terms of both capacity and visiual quality.