The Research For Embedding & Extracting Algorithm Of Video Digital Image Watermark Based On Copy Control

As the popular use of the technology of multimedia, there are more and more data as audio, video has to be encrypted, authenticated and copy protected. The safe of the copyright of the multimedia data and prohibition of the pirate have become a more and more serious problem in the area of digital products. As the essence of digital data is digital signal, if we use cipher to encrypt these data, we will lose the signal property of them. Now we always use "digital watermark" technology to protect their copyright and verify the authenticity and the technology of watermark has become a popular area during these years.In our paper, we first describe some concepts of digital video watermark and some representative algorithm of digital watermark; then we expatiate the algorithm for the use of DVD copy control; then we realize a system of digital watermark; at last, we conclude the work during my master period, and make a prospect for the future.In this discourse, we introduce a new watermark system for the use of DVD copy control. This method use a series of the technology of encryption, coordinated with watermark, we realize the scheme of copy control for uncompress and compressed video. We also describe the change of this scheme to the use of copyright and notation.In the area of uncompressed video, we realize robust watermark (based on DCT transform and DWT transform) and fragile watermark. The encrypted copy control scheme is as followed: First, we input the physical mark P, sequence number K, soft control mark T, then we use the MD5 algorithm to compute the encrypted and, use DES algorithm to encrypt T whose key is , get watermark key by using and, and at the last, we write the encrypted ,and T into the INAM, IKEY, ICOP information which are located in the head of AVI file.When we extract the watermark, we first get the ,, T. If they are existed or can not be decrypted, then we judge this file as pirate and prohibit its play; else we use to decrypted T and get the copy state of this file. Then we compute the watermark key using andand extract it.The robust watermark algorithm is described as followed:Embed:Change one frame from RGB to YUV, make frequency transform on Y, get the coefficient ;Use the insert algorithm, embed the watermark message into the , get the new coefficient ;Make IDCT or IDWT transform to , get the watermarked Y, then do the change from YUV->RGB, get the watermarked frame.Insert the fragile watermark to this frame.Make the operation to every frame in this video stream.Extract:extract the fragile watermark from on frame of a video stream which may have be attacked, if we can't exact the mark successfully, we judge the file have been changed.Change the frame from RGB->YUV, and make frequency transform, then get the coefficient ;Use the watermark extract algorithm to get the watermark , make compare with the primary mark and compute the correlation of them.To judge whether the watermark is exist by the value of .Make these operation to every frame of this video, judge if there are watermark inserted in them.The fragile watermark algorithm is as followed:While inserting, we use the last bit of each byte to compose the sampling sequence; whose length is the number of primary pixels distracts 256. Then we use MD5 to compute the sampling sequence and get the index value, which is 256 bits. At the last we use the index as fragile watermark to insert the last bit of the residuary 256 primary pixels.While extracting, we use the same method as inserting; first we produce a position random sequence with the length of (s-256). Then use MD5 to compute the index and to extract thefrom the last bit of the residuary 256 pixels. If, then the video hasn't been attacked or tampered.Experimental results show that this watermark scheme has a good performance. This watermark system has some characteristics as follows:Combined with the physical mark and sequence key, which are encrypted by MD5, and soft control mark that is encr...