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DATA PROCESSING APPARATUS AND METHOD

  • US 20090257618A1
  • Filed: 12/06/2005
  • Published: 10/15/2009
  • Est. Priority Date: 12/09/2004
  • Status: Abandoned Application
First Claim
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1. A data processing apparatus for registering an image which has been encoded with a two-dimensional water mark pattern, the water mark comprising for each frame of the image a water mark frame pattern of water mark blocks, the water mark pattern comprising a plurality of regions, each region of the pattern including one water mark block selected from a predetermined set of possible water mark blocks in accordance with a key sequence, the key sequence providing a predetermined sequence of selected water mark blocks to form the water mark pattern of each frame to provide a predetermined sequence of water marked frames, the data processing apparatus comprisinga block match processor operableto generate block match probabilities comprising for each region of a current frame of the water marked image a probability surface of possible distortion vectors for each possible water mark block of the set of possible water marked blocks which may have been added to that region of the image frame,a water mark block prior probability calculator operableto form block prior probabilities providing for each region of the current frame of the watermarked image a probability value for each of the possible water mark blocks of the set which may be present in the region using current frame number prior probability value estimates, providing for each possible frame in the predetermined sequence of frames a probability that the frame in the sequence is the current frame of the water marked image,a distortion probability calculator operableto form a spatial prior probability surface for each region of the current image frame from the block prior probabilities and the block match probabilities, providing a probability distribution of distortion vectors for the region,a markov distortion processor operableto adapt the spatial prior probability surface for each region of the current water marked image frame pattern with respect to other the probability surface of each of the other regions in the frame following to a predetermined path through the pattern,to form for each region a current spatial extrinsic probability surface,to form an estimate of a distortion vector for each region from the adapted spatial prior probabilities, anda frame number probability calculator is operableto combine the spatial extrinsic probability surface for each region with the block match probability surface for each of the possible water mark blocks for the region,to form a block extrinsic probability value for each possible water mark block which may be present in the region of the current image frame,to calculate a frame number extrinsic probability value of each of the possible frames in the sequence that the current frame is that frame, by combining the block extrinsic values with the probability of the water mark block for each region, andto update the current frame number prior probability value estimates from the frame number extrinsic probabilities.

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