Chaotic watermarking for a digital image

Abstract

Examples of encoding and decoding a watermark for a digital image and to using the watermark for authenticating the digital image are disclosed. The examples may include embedding a chaotic watermark in a digital image and using parameters associated with source and capture information for the digital image to both generate the chaotic watermark and to authenticate the digital image.

What is claimed is: 
     
         1 . A method comprising:
 extracting a watermark embedded in at least first and second image blocks of a plurality of image blocks of a digital image, the watermark generated from a chaotic sequence generated from at least a first chaotic parameter and a second chaotic parameter, and the first chaotic parameter generated at least from scaling a number representative of the digital image and used as an initial condition to generate the chaotic sequence;   demodulating the chaotic sequence to determine a mean value for the chaotic sequence;   determining the first chaotic parameter and the second chaotic parameter based on the mean value for the chaotic sequence; and   comparing the first and second chaotic parameters to a database to associate at least one of source information and capture information for the digital image with the first and second chaotic parameters.   
     
     
         2 . The method of  claim 1 , comprising receiving the digital image at an I/O interface of a target device from a source device via a network. 
     
     
         3 . The method of  claim 2 , comprising receiving at least a portion of the database at the target device from the source device via a communication channel separate from the network. 
     
     
         4 . The method of  claim 1 , wherein the digital image has been transformed via a discrete cosine transform (DCT) process to comprise the plurality of image blocks, and extracting the watermark from the digital image comprises extracting the watermark via a difference between sums of mid-frequency DCT coefficients for the first and second image blocks. 
     
     
         5 . The method of  claim 1 , wherein the first chaotic parameter is generated at least from normalizing the number representing the digital image. 
     
     
         6 . The method of  claim 1 , wherein the chaotic sequence was generated using a Henon map. 
     
     
         7 . The method of  claim 1 , comprising demodulating the chaotic sequence to determine the mean value for the chaotic sequence using an ergodic demodulator. 
     
     
         8 . The method of  claim 1 , wherein:
 the digital image comprises a medical digital image; and   the capture information for the medical digital image includes patient information for the medical image, the patient information to include one or more of a name of a patient for the medical digital image, an address of the patient, a data of birth of the patient, a social security number for the patient, a medical identification number for the patient or a date the medical digital image was generated.   
     
     
         9 . The method of  claim 1 , wherein:
 the digital image comprises a medical digital image; and   the source information for the medical digital image includes one or more of a location of a source for the medical digital image, a person that generated the medical digital image, a date the medical digital image was generated or a doctor for a patient of the medical digital image.   
     
     
         10 . The method of  claim 1 , comprising:
 reconstructing the watermark to include a reconstructed chaotic sequence based on the first and second chaotic parameters;   comparing the reconstructed chaotic sequence to the chaotic sequence; and   authenticating the digital image based on the comparison between the reconstructed chaotic sequence and the chaotic sequence.   
     
     
         11 . The method of  claim 10 , wherein reconstructing the watermark comprises using the first chaotic parameter as an initial condition to generate the reconstructed chaotic sequence. 
     
     
         12 . A system comprising:
 a decode manager comprising decode logic to:
 extract a watermark embedded in at least first and second image blocks of a plurality of image blocks of a digital image, the watermark generated from a chaotic sequence generated from at least a first chaotic parameter and a second chaotic parameter, and the first chaotic parameter generated at least from scaling a number representing at least a portion of the digital image; 
 demodulate the chaotic sequence to determine a mean value for the chaotic sequence; 
 determine the first chaotic parameter and the second chaotic parameter based on the mean value for the chaotic sequence; and 
 compare the first and second chaotic parameters to a database to associate at least one of source information and capture information for the digital image with the first and second chaotic parameters; and 
   an authentication manager comprising authentication logic to:
 reconstruct the watermark to include a reconstructed chaotic sequence based on the first and second chaotic parameters; 
 compare the reconstructed chaotic sequence to the chaotic sequence; and 
 authenticate the digital image based on the comparison between the reconstructed chaotic sequence and the chaotic sequence. 
   
     
     
         13 . The system of  claim 12 , comprising a first I/O interface to receive the digital at an I/O interface from a source device via a network. 
     
     
         14 . The system of  claim 13 , comprising a second I/O interface to receive the at least a portion of the database via a communication channel separate from the network. 
     
     
         15 . The system of  claim 12 , wherein:
 the digital image has been transformed via a discrete cosine transform (DCT) process to comprise the plurality of image blocks; and   the decode manager is caused to extract the watermark via a difference between sums of mid-frequency DCT coefficients for the first and second image blocks.   
     
     
         16 . The system of  claim 12 , wherein the first chaotic parameter is generated at least from normalizing the number representing the digital image. 
     
     
         17 . The system of  claim 12 , wherein the chaotic sequence was generated using a Henon map, and the first chaotic parameter is used as an initial condition to generate the chaotic sequence. 
     
     
         18 . The system of  claim 12 , the decode logic to demodulate the chaotic sequence to determine the mean value for the chaotic sequence using an ergodic demodulator. 
     
     
         19 . The system of  claim 12 , wherein:
 the digital image comprises a medical digital image; and   the capture information for the medical digital image includes patient information for the medical image, the patient information to include one or more of a name of a patient for the medical digital image, an address of the patient, a data of birth of the patient, a social security number for the patient, a medical identification number for the patient or a date the medical digital image was generated.   
     
     
         20 . The system of  claim 12 , wherein:
 the digital image comprises a medical digital image; and   the source information for the medical digital image includes one or more of a location of a source for the medical digital image, a person that generated the medical digital image, a date the medical digital image was generated or a doctor for a patient of the medical digital image.   
     
     
         21 . The system of  claim 12 , the authentication logic to use the first chaotic parameter as an initial condition to generate the reconstructed chaotic sequence. 
     
     
         22 . The system of  claim 12 , the authentication logic to authenticate the digital image if the reconstructed chaotic sequence matches the chaotic sequence. 
     
     
         23 . A computer program product comprising a non-transitory signal bearing medium having instructions, that when executed by logic, causes the logic to:
 extract a watermark embedded in at least first and second image blocks of a plurality of image blocks of a digital image, the watermark generated from a chaotic sequence generated from at least a first chaotic parameter and a second chaotic parameter, and the first chaotic parameter generated at least from scaling a number representative of the digital image and used as an initial condition to generate the chaotic sequence;   demodulate the chaotic sequence using an ergodic demodulator to determine a mean value for the chaotic sequence;   determine the first chaotic parameter and the second chaotic parameter based on the mean value for the chaotic sequence; and   compare the first and second chaotic parameters to a database to associate at least one of source information and capture information for the digital image with the first and second chaotic parameters.   
     
     
         24 . The computer program product of  claim 23 , the logic caused to receive the digital image at an I/O interface from a source device via a network. 
     
     
         25 . The computer program product of  claim 24 , the logic caused to receiving at least a portion of the database from the source device via a communication channel separate from the network. 
     
     
         26 . The computer program product of  claim 23 , wherein:
 the digital image has been transformed via a discrete cosine transform (DCT) process to comprise the plurality of image blocks; and   the logic is caused to extract the watermark via a difference between sums of mid-frequency DCT coefficients for the first and second image blocks.   
     
     
         27 . The computer program product of  claim 23 , wherein the first chaotic parameter is generated at least from normalizing the number representing the digital image. 
     
     
         28 . The computer program product of  claim 23 , wherein the chaotic sequence was generated using a Henon map. 
     
     
         29 . The computer program product of  claim 23 , the logic caused to demodulate the chaotic sequence to determine the mean value for the chaotic sequence using an ergodic demodulator. 
     
     
         30 . The computer program product of  claim 23 , wherein:
 the digital image comprises a medical digital image; and   the capture information for the medical digital image includes patient information for the medical image, the patient information to include one or more of a name of a patient for the medical digital image, an address of the patient, a data of birth of the patient, a social security number for the patient, a medical identification number for the patient or a date the medical digital image was generated.   
     
     
         31 . The computer program product of  claim 23 , wherein:
 the digital image comprises a medical digital image; and   the source information for the medical digital image includes one or more of a location of a source for the medical digital image, a person that generated the medical digital image, a date the medical digital image was generated or a doctor for a patient of the medical digital image.   
     
     
         32 . The computer program product of  claim 23 , the logic caused to:
 reconstruct the watermark to include a reconstructed chaotic sequence based on the first and second chaotic parameters;   compare the reconstructed chaotic sequence to the chaotic sequence; and   authenticate the digital image based on the comparison between the reconstructed chaotic sequence and the chaotic sequence.   
     
     
         33 . The computer program product of  claim 32 , the logic caused to use the first chaotic parameter as an initial condition to generate the reconstructed chaotic sequence.