摘要:
A method for detecting a watermark signal in digital image data. The detecting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; comparing the extracted signal to a target watermark signal; and declaring the presence or absence of the target watermark signal in the image data based on the comparison. Also provided is a method for inserting a watermark signal in digital image data to obtain a watermarked image. The inserting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; modifying the extracted signal such that it is similar to a target watermark; performing a one-to-many mapping of the modified signal back to log-polar Fourier transform space to obtain a set of watermarked coefficients; and performing an inverse log-polar Fourier transform on the set of watermarked coefficients to obtain a watermarked image.
摘要:
A method for data preparation and watermark insertion. The method includes the step of preparing the data at a first time by manipulating at least one set of the data characteristics for subsequent insertion of a first watermark. In a preferred embodiment of the method of the present invention the method further includes the step of inserting the first watermark by manipulating the set of data characteristics at a second time subsequent to the first time. In still yet another preferred embodiment of the method of the present invention, the method further includes the step of inserting a second watermark at a third time, before, during, or after the first time, by manipulating at least one set of the data characteristics. In a variation of the present invention a method for inserting a watermark into compressed data is provided. The compressed data has sets of data characteristics. The method includes the steps of inserting a watermark by manipulating the set of data characteristics; and optimizing the manipulated data by modifying the compressed data characteristics subject to a set of constraints.
摘要:
A method for data preparation and watermark insertion. The method includes the step of preparing the data at a first time by manipulating at least one set of the data characteristics for subsequent insertion of a first watermark. In a preferred embodiment of the method of the present invention the method further includes the step of inserting the first watermark by manipulating the set of data characteristics at a second time subsequent to the first time. In still yet another preferred embodiment of the method of the present invention, the method further includes the step of inserting a second watermark at a third time, before, during, or after the first time, by manipulating at least one set of the data characteristics. In a variation of the present invention a method for inserting a watermark into compressed data is provided. The compressed data has sets of data characteristics. The method includes the steps of inserting a watermark by manipulating the set of data characteristics; and optimizing the manipulated data by modifying the compressed data characteristics subject to a set of constraints.
摘要:
A watermark message embedded in a cover work can be made robust to various types of post-embedding operations, while simultaneously minimizing perceptual impact on the cover work. This is accomplished by the informed coding of the watermark message to be embedded. This is also accomplished by the informed embedding of the watermark message code in the cover work. Finally, the watermark message code may be perceptually shaped to minimize impact on the fidelity of the watermarked work. Further, these techniques may be combined for maximum effect.
摘要:
A method for utilizing a title signal contained in data through a comparison of the title signal to a player signal stored in a player device is provided. Preferably, the data is digital image, video, or audio data. The method includes the steps of: providing data having the title signal; detecting, at the player device, the title signal in the data: comparing the title signal to the player signal stored at the player device; and performing an action based upon the comparison. In a preferred implementation, the action is performed if the title signal matches the player signal, and the action is to inform the device user of the match and the winning of a prize. In another preferred implementation, the title signal is a subsignal of a watermark signal encoded in the digital data, in which case the method further comprises the steps of: extracting the watermark signal from the digital data; and decoding the subsignal. Also provided are devices, such as DVD players/recorders, for carrying out the methods of the present invention.
摘要:
Data is protected from unauthorized copying by rescrambling an unauthorized version of the data, but descrambling an authorized version of the data. This is done using a trigger signal. One property of the trigger signal is that it is preserved through signal transformations, such as one or more of compression, decompression, analog to digital conversion, and digital to analog conversion. As a result of this property the trigger signal can be detected in either scrambled or descrambled data. The trigger signal is embedded into the data to form watermarked data. The watermarked data is passed through a descrambler, where the trigger signal, if present, is extracted. A descrambling key and a descrambling algorithm are applied to the watermarked data if the trigger signal is present, but not applied to the watermarked data if the trigger signal is not present.
摘要:
A method for utilizing a title signal contained in digital data through a comparison of the title signal to a player signal stored in a player device. The method includes the steps of: downloading the digital data having the title signal via an Internet connection; possibly transferring the downloaded digital data to the player device; detecting, at the player device, the title signal in the data: comparing the title signal to the player signal stored at the player device; and performing an action based upon the comparison. In a preferred implementation of the present invention, the player device is a personal computer and the digital data is either image, video, audio or multimedia data or is an application program for running on the personal computer. Preferably, the player device is a personal computer. In other embodiments the title signal is contained in or part of an application program or is contained in data to be input into the application program.
摘要:
A watermarking procedure that is applicable to images, audio, video and multimedia data to be watermarked divides the data to be watermarked into a set of n×n blocks, such as the 8×8 blocks of MPEG. The same watermark signal can be distributed throughout the set of blocks in a large variety of ways. This allows the insertion algorithm to be changed without affecting the decoders. The decoding procedure first sums together the DCT coefficients of N sets of 8×8 blocks to form a set of N summed 8×8 blocks and then extracts the watermark from the summed block. Since the sum of the DCT blocks is equal to the DCT of the sum of the intensity blocks, efficient decoding can occur in both the spatial and frequency domains. The symmetric nature of the decoding process allows geometric distortions to be handled in the spatial domain and other signal distortions to be handled in the frequency domain. Moreover, insertion of a watermark signal into image data and the subsequent extraction of the watermark from watermarked image data which has been subject to distortion between the times of insertion and extraction involves the insertion of multiple watermarks designed to survive predefined distortions of the image data, such as panscan or letterbox mode transformations. Alternatively, a registration pattern in the image data, after the image data containing the registration pattern is subject to an unknown distortion, is used to compensate for distortion of the watermarked image data.
摘要:
A computer-implemented process for determining a ranked set of solutions to a bipartite graph matching problem, such is involved in multi-target tracking, maximum flow matching, or data association in matching elements of a first set to elements of a second set to minimize the cost of the association. A feature of the process is a partitioning into subproblems such that the most probable solutions are in the smaller subproblems and the computation begins by solving the smallest subproblem in the search for the best solution.
摘要:
A method for inserting a digital signature into digital data is provided. The digital data has bits and the method includes the steps of: assigning predetermined bits of the digital data for receiving the digital signature; signing the digital data excluding the predetermined bits resulting in the digital signature; and inserting the digital signature into the predetermined bits of the digital data for subsequent authentication of the digital data. Also provided is a method for authenticating digital data having the embedded digital signature in the predetermined bits of the digital data including the steps of: extracting the digital signature from the predetermined bits; decrypting the digital signature from the digital data resulting in a first hash; applying a known one-way hashing function used by an encoder of the digital data to the digital data excluding the predetermined bits resulting in a second hash; and comparing the first hash to the second hash wherein if the first hash matches the second hash the digital data is authentic. In a preferred version of the methods of the present invention, the method further includes the step of inserting associated data into the digital data prior to the signing step such that the digital signature authenticates both the associated data as well as the digital data. Preferably, the associated data is inserted into the bits of the digital data excluding the predetermined bits.