摘要:
A watermark decoding method makes use of a line-finding algorithm (e.g., the Radon transform) to determine rotation of an image from an initial orientation. Once rotation has been characterized, differential scaling of the image can readily be determined.
摘要:
A content watermarking method derives a watermark key from data representing content. In one particular method, a plural symbol message is algorithmically transformed in dependence on the derived watermark key. In another arrangement, the key specifies how or where the message is embedded in the content. A variety of other features and arrangements are also detailed.
摘要:
The present invention provides methods and apparatus that are helpful for identifying or protecting video. One claim recites a method including: receiving data representing picture elements of video; transforming the data into a frequency domain; comparing characteristics associated with the transformed data to predetermined characteristics that are associated with a first video type, and if the characteristics coincide, determining that the video is of the first video type; and if the characteristics do not coincide, comparing the characteristics of the transformed data to predetermined characteristics that are associated with a second video type, and if the characteristics coincide, determining that the video is of the second video type. Another claim recites a method including: obtaining information associated with a video; selecting a set of information from the obtained information; deriving identifying information from the selected set of information; and providing a security feature in or over data representing picture elements of the video according to the identifying information. Of course, other implementations are provided as well.
摘要:
A digital watermark detection method uses a matched filtering technique on a log polar re-mapping of a watermarked signal to detect peaks associated with a repetitive structure of a watermark.
摘要:
The present invention provides processes to encode substrates (e.g., paper, synthetics, etc.) with information, and substrates including signals encoded therein. One claim recites a substrate-making process including: obtaining an element to be utilized in a substrate-making process, the element including a property to introduce a texture pattern including an encoded signal into a substrate, the encoded signal being machine-detectable from image data corresponding to at least a portion of the texture pattern, the encoded signal including a variable component; and utilizing the element to impart the texture pattern into a substrate during the substrate-making process. Another claim recites a physical substrate including: a surface having a texture pattern provided in the surface during a substrate-making process. The texture pattern includes a machine-readable signal that is detectable from image data corresponding to at least a portion of the texture pattern. The signal includes a variable component that has discernable properties in a frequency domain. The texture pattern is provided in the surface during the substrate-marking process by a non-printing element. Of course, other claims and combinations are also provided.
摘要:
A wavelet domain watermark encoder and decoder embed and detect auxiliary signals in a media signal, such as a still image, video or audio signal. The watermark encoders and decoders employ techniques that take advantage of processing plural levels of resolution of the signal to embed and detect auxiliary information in the media signal.
摘要:
The present invention provides techniques that are helpful in resolving the authentication of an identification document or banknote. The document or banknote includes a security enhancer. The enhancer can be a graphic or artwork design, or can be realized with line art. In the case of an identification document, the spatial characteristics of the security enhancer are preferably altered in accordance with information contained in the identification document. For example, if the ID document includes a photograph, a hashing algorithm will reduce the photograph to a number. The number is used to set a repeated spacing distance of elements in the security enhancer. The repeated spacing yields an identifiable frequency response that is related to the identification document photograph.
摘要:
A method and apparatus for compressing a dissolve region within a sequence of digital motion video frames. A function is calculated based on statistical data derived from frames in the sequence. Dissolve region boundaries are then detected based on characteristics of the calculated function. Consecutive detected boundaries may be flagged as a dissolve region based on the average value of the function between the consecutive detected boundaries and the distance between the consecutive detected boundaries.
摘要:
A method and apparatus for detecting a fade within a sequence of digital motion video frames. A first frame and a previous frame are selected from the sequence as first and second regions, respectively, for processing. The mean of the first region and the mean of the second region are each calculated and the relative mean change between the means is determined. A fade is detected if the relative mean change exceeds a first predetermined threshold. Alternatively, a fade is detected if the relative mean change is less than the first predetermined threshold but greater than a second predetermined threshold and the magnitude of the difference between the means is greater than a third predetermined threshold.
摘要:
The present invention relates generally to digital watermarking. In one implementation, we provide a hierarchical digital watermark detector method. The method includes: i) in a first layer of a hierarchical search, performing watermark detection on blocks of at least a portion of an incoming suspect signal; ii) identifying a first block in the portion that is likely to include a decodable digital watermark; and iii) in a second layer of the hierarchical search, performing additional watermark detection on overlapping blocks in a neighborhood around the first block. Another implementation provides a hierarchical watermark detector including a buffer and a detector. The buffer stores portions of an incoming signal. The detector evaluates watermark detection criteria for blocks stored in the buffer, and hierarchically zooms into a neighborhood of blocks around a block associated with watermark detection criteria that satisfies detection criteria.