Watermarking
First Claim
1. A method of embedding a watermark signal comprising a series of watermark values in a picture signal comprising a series of picture sample values, the method comprising adjusting picture sample values based on watermark values, characterised in that adjusting comprises, for each watermark value:
- combining the watermark value with a respective subset of the picture sample values using a plurality of adjustment factors, each adjustment factor being based on a local estimate of the visibility of the watermark at a corresponding picture sample location.
0 Assignments
0 Petitions
Accused Products
Abstract
A watermarketing system and method is proposed for still or moving pictures in which a watermark is embedded robustly and simply into DC-values, but without causing unacceptable visible picture degradation. The watermark is secure and can be readily detected, and the method can be used to convey additional data. Also disclosed is a method for watermarking a sequence of pictures in which the visibility of artifacts is reduced. The watermark may carry data and may be used to label a programme.
-
Citations
81 Claims
-
1. A method of embedding a watermark signal comprising a series of watermark values in a picture signal comprising a series of picture sample values, the method comprising adjusting picture sample values based on watermark values, characterised in that adjusting comprises, for each watermark value:
combining the watermark value with a respective subset of the picture sample values using a plurality of adjustment factors, each adjustment factor being based on a local estimate of the visibility of the watermark at a corresponding picture sample location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 52, 53, 54, 55, 56, 57, 58, 60, 61, 73, 74, 75)
- 20. A method of embedding a watermark within a sequence of pictures corresponding to a motion video sequence wherein the watermark is combined with picture sample values characterised in that the method of combining varies from picture to picture to reduce the appearance of static artifacts in the sequence.
-
25. A method of embedding a watermark within a sequence of pictures corresponding to a motion video sequence, wherein the watermark is combined with picture sample values characterised in that the method of combining includes generating a motion-compensated version of the watermark to reduce the appearance of static artifacts in the sequence.
- 26. A method of embedding a watermark within a sequence of pictures corresponding to a motion video sequence, wherein the watermark is combined with picture sample values characterised in that the method of combining includes estimating average motion between the pictures and combining the watermark to reduce the appearance of static artifacts in the sequence.
-
35. (canceled)
-
45-51. -51. (canceled)
-
59. A method of detecting a motion-compensated watermark comprising:
-
estimating the cumulative average motion in a sequence of pictures;
computing an average picture taking into account the average motion in the pictures;
calculating the cross-correlation function of the motion-compensated average picture and the watermark.
-
-
62. A method of decoding data in a picture signal comprising determining local mean values of picture samples corresponding to regions of the picture in which data is carried;
- comparing said local mean values to estimated or reference local mean values for said regions in the absence of the data, and determining a data value from the result of each comparison, wherein preferably the data value is determined from at least the sign of the difference between the determined local mean value and the estimated or reference local mean value.
-
63. A method of embedding data comprising a series of data values in a picture comprising a series of picture values comprising defining a plurality of subsets of the picture values, one subset for each data value, and adding an adjustment factor to each picture value in each subset, a first component, preferably the magnitude, of each adjustment factor being a function of an estimate of the visibility of embedded data at the picture value location and being variable between the picture values of each subset, a second component, preferably the sign, of the adjustment factor being determined by the data value and being substantially constant for the picture values of each subset.
- 64. A method of embedding a watermark signal comprising a series of watermark values in a picture signal comprising a series of picture sample values the method comprising adjusting picture sample values based on watermark values including generating the watermark by convolving a key with a repeated data sequence to produce a data-carrying watermark.
- 65. A method of generating a watermark encoding data to be applied to a picture comprising convolving a key comprising a plurality of bits with a plurality of bits of data.
-
70. A method of embedding a watermark in a moving picture comprising changing the watermark or moving the watermark, preferably substantially randomly, at a shot change, or following detection of an accumulated change in picture content above a predetermined threshold.
-
71. A method of embedding a data-carrying watermark in a moving picture comprising changing the data carried by the watermark at a shot change, or following detection of an accumulated change in picture content above a predetermined threshold.
-
72. A method of embedding a data-carrying watermark in a moving picture comprising moving the watermark when the data content of the watermark changes, preferably at a shot change or following detection of an accumulated change in picture content above a predetermined threshold.
-
78. A method of detecting a watermark in a sequence of moving pictures comprising determining an expected position of the watermark and thereafter detecting the watermark based on the expected position, wherein the expected position is re-determined following a shot change or a change in picture content above a threshold.
-
79. (canceled)
-
80. A method of embedding data in a picture comprising:
-
generating a data-carrying watermark having a plurality of watermark values by convolving a set of data comprising a plurality of bits of data with a key comprising a plurality of bits;
applying the watermark to the picture by combining each watermark value with a plurality of picture values based on a local estimate of the visibility of the watermark - View Dependent Claims (81)
-
Specification