Reversible Data Hiding Based On Pixel Combination In Digital Images

With the popularization and widespread application of information technology and multimedia transmission,the protection of secret data and multimedia security issues have caused concern.Digital multimedia includes text,image,audio,video,etc.Among them,digital image is the most widely used and convenient.It has the characteristics of rich content,good visual effects,and small size,so secret data hiding based on digital image has more important research value.At present,the reversible data hiding in digital images still has the problems of large distortion and low embedding rate,especially in encrypted images,because there is no redundancy between pixels,so it faces greater challenges.This article first introduces the research background and significance of digital image reversible data hiding,briefly expounds the research status of digital image reversible data hiding technology,and analyzes the existing problems and defects in existing work.Then summarize the main work of this article,and introduce the basic theoretical knowledge required,including reversible data hiding in grayscale images and grayscale encrypted images.For different carriers and application backgrounds,based on the principle of pixel combination,this paper proposes an image encryption method,two reversible data hiding methods.The main contributions of the paper include:(1)A reversible data hiding scheme based on gray image is proposed.By leveraging the secret data coding using the remainder storage based exploiting modification direction(RSBEMD),and the pixel change operation recording based on multi-segment left and right histogram shifting,a novel reversible data hiding(RHD)scheme is proposed in this paper.The secret data are first encoded by some specific pixel change operations to the pixels in groups.After that,multi-segment left and right histogram shifting based on threshold manipulation is implemented for recording the pixel change operations.Furthermore,a multiple embedding policy based on chess board prediction(CBP)and threshold manipulation is put forward,and the threshold can be adjusted to achieve adaptive data hiding.Experimental results and analysis show that it is reversible and can achieve good performance in capacity andimperceptibility compared with the existing methods.(2)A reversible data hiding algorithm for encrypted images is proposed.The original carrier is first encrypted.The encryption framework is composed of two processes: Tromino scrambling encryption and in-block stream encryption.After encryption,according to the histogram characteristics,the adaptive pixel value ordering(PVO)is used for embedding.Compared with existing methods,the visual quality of the directly decrypted image is better under the same embedding capacity.What's more,the data extraction and recovering of carrier images are separable.The research outcomes of this paper can be applied to image data hiding and cloud storage security,and thus open up a new gate for transmission of important information securely and secretly,improving the RDH performance in digital image...