摘要:
Methods, apparatus, and systems for signal continuity assessment using embedded watermarks are provided. The embedded watermarks are recovered from the content and one or more attributes associated with the recovered watermarks are identified. A continuity of the content can then be assessed in accordance with the one or more attributes. The continuity assessment may be based on a variety of factors, including but not limited to a determined heartbeat of the recovered watermarks, a density, separation, location, or extent, of the recovered watermarks, as well as information associated with the watermarks, such as a stego key, channel bits, packet numbers, a fingerprint, or the like.
摘要:
Methods, devices and computer program products facilitate the extraction of embedded watermarks in the presence of content distortions. Subsequent to the detection of a tentative watermark, particular sections of the content are examined to form one or more extrapolated watermarks or watermark segments. Weights are assigned to the extrapolated watermarks or watermark segments, and used in combination with the detected tentative watermark to collectively assess if a desired probability of false detection is satisfied.
摘要:
Methods, devices and computer program products facilitate the extraction of embedded watermarks in the presence of content distortions. Subsequent to the detection of a tentative watermark, particular sections of the content are examined to form one or more extrapolated watermarks or watermark segments. Weights are assigned to the extrapolated watermarks or watermark segments, and used in combination with the detected tentative watermark to collectively assess if a desired probability of false detection is satisfied.
摘要:
Methods and devices are provided to thwart analysis of a watermarking system by preventing analysis of watermarks in a host content. Upon receiving a content at a watermark embedding device, the content is analyzed to ascertain whether one or more test features are present in at least a first portion of the received content. When the analysis reveals that one or more test features are present, embedding of watermarks in at least the first portion of the received content is disabled. The test features of interest include a temporal, a spatial and/or a frequency characteristic such that, if a region of the content that includes test feature is embedded with a watermark, at least one characteristic of the embedded watermark is detectable upon analysis of that region. The test feature can, for example, approximate an impulse signal, a step function signal or a pure sinusoidal signal.
摘要:
A system for using a watermark embedded in an audio signal to remotely control a device. Various devices such as toys, computers, and appliances, equipped with an appropriate detector, detect the hidden signals, which can trigger an action, or change a state of the device. The watermarks can be used with a “time gate” device, where detection of the watermark opens a time interval within which a user is allowed to perform an action, such as pressing a button, typing in an answer, turning a key in a lock, etc.
摘要:
Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of predefined quantization values corresponding to an information symbol to be encoded. The amount of change required to modify the signal feature to the determined target quantization value is calculated and the cover signal is modified accordingly to so change the feature value over a predefined interval. Information symbols are extracted by the opposite process. In one embodiment, the predefined value is a short term auto correlation value of the cover signal.
摘要:
Methods, devices, and computer program products facilitate the application of a content use policy based on watermarks that are embedded in a content. Watermark extraction and content screening operations, which can include the application of content usage enforcement actions, may be organized such that some or all of the operations can be conducted at different times by different devices. These operations can be conducted by one or more trusted devices that reside in a networked environment. Real-time access to a content can also be facilitated by utilizing existing watermark extraction records. To facilitate real-time access to the content, the extraction records may contain segmented authentication information that correspond to particular segments of the content that is being accessed. Additionally, or alternatively, new watermark extraction operations can be conducted in real-time to produce new watermark extraction records.
摘要:
Methods for adapting the operation of a system in response to the detection of embedded watermarks from a digital host content are provided. A digital host content is received and examined for the presence of watermarks. In response to the detection of embedded watermarks and in accordance with the value, type, density or spacing of the detected watermarks, one or more system reactions may take place. These reactions include conditionally allowing the system to resume its normal operation, prohibiting the system from resuming its normal operation, degrading the quality of the digital host content or changing the security status of the digital host content. In response to the extraction of weak watermarks that do not meet the desired system requirements, the extraction operation may be modified or extended to enable the detection of strong watermarks.
摘要:
Methods and apparatus for thwarting circumvention of watermark detection are provided. When content is received at a device that is equipped with a watermark extractor, an attacker may disguise the form of the received content in an attempt to circumvent detection of watermarks that are embedded in the content. A signal processing operation is performed on the received content such that the signal processing operation does not significantly degrade the perceptual quality of the content if the content is indeed in the form that is purported to be. The signal processing operation, however, significantly degrades the perceptual quality of the content if the content is in a different form, thereby discouraging the attacker's attempts to thwart watermark detection.
摘要:
A system for using a watermark embedded in an audio signal to remotely control a device. Various devices such as toys, computers, and appliances, equipped with an appropriate detector, detect the hidden signals, which can trigger an action, or change a state of the device. The watermarks can be used with a “time gate” device, where detection of the watermark opens a time interval within which a user is allowed to perform an action, such as pressing a button, typing in an answer, turning a key in a lock, etc.