Research On Video Watermarking Technology For Cloud Computing

With the rapid development of cloud computing and the widespread use of video,cloud video is easily copied,misappropriated,and destroyed during storage and transmission.Digital watermarking is an effective way to protect the ownership and copyright of digital products in the cloud,which has made breakthrough progress in recent years.In this thesis,the basic theory and method of digital watermarking are studied.Combining human minimum visual error model and wavelet transform theory,an improved image watermarking technology based on DWT for cloud computing is proposed and applied to the field of video watermarking.First of all,this thesis introduces the research background and significance of digital watermarking,describes the research status of digital watermarking technology at home and abroad,and briefly summarizes the application of the technology.Then,the basic theory of image digital watermarking and video digital watermarking,wavelet transform theory and application,common signal encryption algorithm,and digital watermarking algorithm based on DWT as well as its improved algorithm are introduced.In the next,two digital image watermarking algorithms based on wavelet transform are described.One is an image zero-watermarking algorithm based on wavelet transform with tamper-targeting capability.The algorithm has good robustness and strong anti-attack capability,but it requires a large amount of computation and a large storage space for video watermarking;the other is based on hyperchaos RBF neural network adaptive image watermarking algorithm,this algorithm has strong security,invisibility and good robustness.And then,an improved image watermarking algorithm based on DWT is proposed.The algorithm uses the chaotic DHNN system to encrypt the watermark information.Based on the human minimum visual error model and the distortion cost of each wavelet coefficient position,watermark information is embedded on low frequency wavelet coefficients after the image wavelet decomposition.Experimental results show that the algorithm has good security,invisibility and robustness.In addition,the algorithm has a small amount of computation and does not require much data storage space,and can be applied to video watermarking.Finally,an improved image watermarking algorithm based on DWT is applied to the video,and the key frames of the video sequence are extracted based on the color features,and then the watermark information is embedded according to the human visual model and keyframe distortion cost.Experimental results show that the video watermarking algorithm has good security and invisibility and has better robustness against various attacks.