Research On Image Reversible Information Hiding Algorithm For Contrast Enhancement And Cloud Secure Transmission

With the development of digital technology and the enrichment of information,the reversible data hiding technology(RDH)is born which embeds secret information into different types of data carriers.In the data extraction stage,the receiver can completely extract the secret information from these data carriers.At the same time,the original data carrier can be restored without any loss.This paper studies the image contrast enhancement and image cloud secure transmission respectively based on reversible data hiding technology.The main research contents are as follows:(1)Aiming at the problem that the grayscale medical images usually have low contrast,this paper is focused on medical images and the up-to-date RDH methods,and implements an automatic contrast enhancement algorithm called the RDHACEM algorithm considering two metrics: larger embedding capacity and better image visual quality.The proposed algorithm separates medical images into regions of interest(ROI)and regions of non-interest(NROI).It automatically stretches the ROI's grayscale histogram to simultaneously enlarge the embedding capacity of the ROI and enhance the image contrast.Experimental results show that the marked medical images generated by the proposed algorithm have better visual quality and larger embedding capacity in the ROI than those generated by the up-to-date RDH methods.(2)The reversible data hiding with contrast enhancement(RDHCE)has become a hot topic in many fields.The RDHCE methods for grayscale images have made great achievements.However,applying RDHCE methods to color images needs to solve the problem of color distortion.This paper proposes an RDHCE method for color images based on constant hue plane.It firstly separates the color images into min,mid and max channels.Then,the mid channel is used for data hiding,and min and max channels are hue-preserved to avoid color distortion.Finally,the three channels compose a contrast enhanced color image.The experimental results show that the proposed method achieves the best enhanced results based on CIEDE2000 compared with the state-of-the-art methods.(3)Image encryption is used for privacy protection in cloud computing.Nowadays,reversible data hiding in encrypted image(RDHEI)has achieved great success with the demand of embedding additional information into encrypted image.The existing algorithms cannot implement large embedding capacity and good reconstructed image quality simultaneously.Besides,the universality of some methods is limited when they are used in images with different textural characteristics.In this work,an RDHEI method based on most significant bit(MSB)prediction and error embedding is proposed.On one hand,all types of prediction errors are considered in the proposed method,therefore all the pixels with prediction errors can be recovered correctly.On the other hand,error blocks are utilized to mark the locations of prediction errors and message blocks are utilized to embed data.Moreover,flag blocks are utilized to distinguish error and message blocks.To solve the problem of misjudgement for flag blocks in the decoding phase,special operations are conducted on error blocks and message blocks.Experimental results demonstrate that,compared with the state-of-the-art RDHEI methods,the proposed method has good universality on well-known databases.