Reversible Data Hiding Algorithm Based On Contrast Enhancement

With the popularization of network technology and the widespread dissemination of digital information on the network,securing digital information has become an urgent problem to be solved.Traditional encryption technology and information hiding technology will cause permanent distortion of the original carrier image,resulting in the loss of the original carrier.Reversible data hiding(RDH)can recover the original carrier without loss while correctly extracting secret information.Therefore,reversible information hiding has broad application prospects in military images,medical images,legal images and other fields that require high carrier.Traditional reversible information hiding usually uses Peak Signal to Noise Ratio(PSNR)as an evaluation index of image quality,but for low brightness images,improving the visual quality of images is more important than maintaining a high PSNR.Although the PSNR of the image is reduced,the contrast is improved to show the image details more clearly.Therefore,this paper based on contrast-enhanced reversible information hiding has done research,taking digital images as the research object,and the following research on image histogram and edge-enhanced reversible information hiding algorithm:Firstly,we propose a reversible information hiding algorithm based on histogram specification.The hyper-contrast enhancement problem caused by the reversible information hiding of histogram equalization combines the histogram specification with the reversible information hiding of histogram shifting.Applied in low illumination images,the histogram is specified as a single mapping according to the local histogram distribution,providing a reasonable histogram distribution for the low brightness histogram,and then using the histogram shifting algorithm to directly fill the histogram redundancy to achieve data hiding.This algorithm provides the distribution of the histogram,controls the shifting range of the histogram,and controls the contrast enhancement within the specified range,which improves the contrast over-enhancement caused by the traditional shifting algorithm.Experiments have shown that under low illumination images,more than 1bpp of hidden capacity can be embedded with higher contrast image vision and better hiding performance.Secondly,we propose a reversible information hiding algorithm based on image sharpening,which combines Laplacian sharpening with difference expansion(DE)and digital inverse transformation.The texture details are lost and hidden for traditional algorithms.Restricted,we consider the principle of image sharpening applied to the reversible information hiding algorithm to enhance image details such as image edges and textures.The image is divided into Laplacian template convolutions,in order to make the central pixels unaffected by the selection interval,to ensure the reversibility of the information,the response value is superimposed with the central pixel and the embedded information to obtain a sharpened image.The experimental results show that the algorithm has higher embedding capacity and better visual effect while the image is sharpened.