Detecting watermark modifications
First Claim
1. A system to detect watermark modifications, the system comprising:
- a watermark encoder to encode a second watermark in a sampled media signal obtained from a received broadcast signal, the sampled media signal already encoded with a first watermark that was included in the received broadcast signal;
a watermark decoder to detect the first watermark and the second watermark in the sampled media signal;
a watermark modification evaluator to compare a first metric determined for the first watermark and a second metric determined for the second watermark to determine whether the first watermark was modified prior to being included in the received broadcast signal; and
a ratings server to revise ratings data corresponding to the received broadcast signal when the first watermark is determined to have been modified prior to being included in the received broadcast signal.
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Accused Products
Abstract
Example systems disclosed herein to detect watermark modifications include a watermark encoder to encode a second watermark in a sampled media signal obtained from a received broadcast signal, the sampled media signal already encoded with a first watermark that was included in the received broadcast signal. Disclosed example systems also include a watermark decoder to detect the first watermark and the second watermark in the sampled media signal, and a watermark modification evaluator to compare a first metric determined for the first watermark and a second metric determined for the second watermark to determine whether the first watermark was modified prior to being included in the received broadcast signal. Disclosed example systems further include a ratings server to revise ratings data corresponding to the received broadcast signal when the first watermark is determined to have been modified prior to being included in the received broadcast signal.
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Citations
20 Claims
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1. A system to detect watermark modifications, the system comprising:
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a watermark encoder to encode a second watermark in a sampled media signal obtained from a received broadcast signal, the sampled media signal already encoded with a first watermark that was included in the received broadcast signal; a watermark decoder to detect the first watermark and the second watermark in the sampled media signal; a watermark modification evaluator to compare a first metric determined for the first watermark and a second metric determined for the second watermark to determine whether the first watermark was modified prior to being included in the received broadcast signal; and a ratings server to revise ratings data corresponding to the received broadcast signal when the first watermark is determined to have been modified prior to being included in the received broadcast signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer readable medium comprising computer readable instructions that, when executed, cause a processor to at least:
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encode a second watermark in a sampled media signal obtained from a received broadcast signal, the sampled media signal already encoded with a first watermark that was included in the received broadcast signal; detect the first watermark and the second watermark in the sampled media signal; compare a first metric determined for the first watermark and a second metric determined for the second watermark to determine whether the first watermark was modified prior to being included in the received broadcast signal; and revise ratings data corresponding to the received broadcast signal when the first watermark is determined to have been modified prior to being included in the received broadcast signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A watermark modification detector comprising:
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means for encoding a second watermark in a sampled media signal obtained from a broadcast media signal received by a media device, the sampled media signal including a first watermark that was included in the broadcast media signal; means for detecting the first watermark and the second watermark in the sampled media signal; and means for comparing a first strength metric determined for the first watermark and a second strength metric determined for the second watermark to determine whether the first watermark was modified prior to being encoded in the broadcast media signal that was received by the media device. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification