| The current level of information technology has greatly promoted the development of multimedia.More and more people pay attention to the authentication and property protection of multimedia data.Digital watermarking technology has become a hot field.Compared with the traditional digital watermarking technology,reversible watermarking technology can ensure the visual effect of the image,restore the carrier image and watermarking image losslessly,meet the requirements of image quality in remote sensing,medicine,law,military and other fields,and reversible watermarking technology was not limited to the space domain,but also widely used in the transformation domain and the improved encryption domain.In this paper,image data was used as the carrier for research.On the premise of ensuring image quality,in order to improve the embedding capacity of watermarking,the algorithm of reversible watermarking was studied.On the basis of common spatial domain and transform domain algorithm,the algorithm of reversible watermarking in spatial domain was improved,and the research of algorithm in encryption domain was increased.The advantages and disadvantages of algorithm in encryption domain are discussed,and the algorithm was modified Enter.Through the research of reversible watermarking algorithm in spatial domain,it was found that the algorithm with the best performance and application belongs to the algorithm of difference expansion and histogram translation,and the two algorithms are integrated and improved.A reversible watermarking algorithm based on three neighborhood prediction difference histogram was proposed.Firstly,the image was divided into three neighborhood blocks,and then the three neighborhood pixel blocks after the block are predicted To generate histogram,we can get a more steep peak value,which can increase the embedding capacity,ensure the visual effect of the image and reduce the difficulty of the algorithm.Reversible watermarking belongs to fragile watermarking and has low anti attack ability.It was found that it was difficult to increase the robustness of reversible watermarking.Therefore,we can encrypt the carrier image to form a ciphertext map in the encrypted domain.As to reduce the possibility of image being attacked,it was a feasible direction to realize reversible watermarking technology in the encrypted domain image.Due to the loss of correlation between pixels in the image in the encryption domain,the common spatial encryption algorithm was not applicable.A reversible watermarking algorithm based on integer transform was proposed.The image in the spatial domain was scrambled and encrypted by two mapping methods,and the encrypted image was even processed After embedding the watermarking,the watermarking image was obtained.According to the parity of the watermarking image,the watermarking image was improved Take the watermarking information to realize reversible watermarking in the encryption domain. |
