Research On High-fidelity Reversible Watermarking Algorithm

With the rapid development of computer network technology,various digital multimedia information is transmitted through the network,which brings great convenience to people's daily life,but also brings a series of information security problems.To solve these problems,people have introduced digital watermarking technology,which is an effective means of covert communication,copyright protection and digital signature.However,traditional digital watermarking technology can only play a role in protecting secret information,and can not restore the original carrier completely after extracting the watermark,which makes it impossible to apply to medical,judicial and military fields requiring high fidelity.In order to overcome this shortcoming,a reversible watermarking technology was born.As an important branch of the field of information security,reversible watermarking technology can not only correctly extract the embedded watermark,but also restore the original carrier completely.Therefore,reversible watermarking technology has become a hot research direction.This paper first discusses the research background and current research status of reversible digital watermarking,and then introduces the basic theory,classification and performance requirements in different application scenarios of digital watermarking.This paper mainly studies image reversible watermarking technology based on compressed domain and spatial domain.The main contributions of the paper include:1.A novel reversible watermarking algorithm for vector quantization(VQ)compressed coding based on joint neighboring coding is proposed.This method uses genetic algorithm technology to rearrange the indices,so that the spatial correlation of the resulting indices matrix is stronger,which is advantageous to predictive coding.Then LSE prediction technology is used to calculate the prediction error according to the weights of the four neighboring indices of the current index,and classify the coding situation according to the frequency of the prediction error,thereby effectively reduce the code stream length.Experimental results show that the proposed algorithm effectively reduces the bit rate and improves the image compression performance for various images and codebook sizes.2.A reversible watermarking algorithm based on the combination of IPVO and PVO(pixel-value-ordering)is proposed.In this method,after dividing the cover image into blocks,the pixels within a given block are ordered according to their values,and then based on theprediction-error expansion technology,the PVO algorithm is used to predict and modify the maximum and minimum values of each pixel block to embed data.At the same time,in order to obtain greater embedding capacity,the IPVO algorithm is combined to predict and modify the second largest and second smallest values of each pixel block to embed data.,The pixel value order of each block remains unchanged after the data embedding,and ensuring the reversibility of the algorithm.Experimental results show that the proposed algorithm can make better use of the image redundancy and achieve better embedding performance while maintaining low distortion.