466 results about "Watermark method" patented technology

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. In one implementation, an identification document includes electronic circuitry. The electronic circuitry includes an image of an authorized bearer of the identification document. The image includes first digital watermarking having a plural-bit identifier. In some cases, the identification document includes a printed image of the authorized bearer of the identification document. The printed image includes second digital watermarking therein. The first digital watermarking and the second digital watermarking can be cross-correlated for authentication of the identification document.

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.

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

The invention relates to a reversible video frequency watermark method based on interframe forecast error histogram modification, comprising watermark embedding and watermark detection. The watermarkembedding process is carried out according to a video frequency negative sequence: firstly, utilizing the previous frame to carry out motion estimation to obtain an interframe forecast error, and thencarrying out the histogram modification on the interframe forecast error so as to embed a watermark. An extracting process is carried out according to a video frequency sequence mode: similarly, utilizing the previous frame to carry out the motion estimation to obtain a forecast error, and then extracting a watermark from the forecast error, and modifying a histogram to carry out the frame imagerecovery. The invention uses the mode of negative sequence embedding and sequence extracting, thereby an embedded video frequency frame can be recovered after the watermark is extracted, and the reversibility of the video frequency watermark is realized; the motion estimation is used according to the content relation of adjacent interframes to carry out prediction so as to enable the forecast error histogram to have the height centrality, and realize the bigger embedding content; in the embedding process, using the histogram modification enables that the influence on the frame image is small,and a watermark-embedded video frequency has high visual quality.

The invention discloses a digital watermark method capable of simultaneously resisting various attacks, belonging to the field of digital watermark. The invention particularly relates to a digital watermark method capable of simultaneously resisting attacks, such as clipping, scaling, filtering, noise and the like. At present, the most published digital watermark technologies only can resist certain common geometric attacks, noise attacks and filtering attacks, wherein geometric attacks do not contain clipping attacks, only one attack can be resisted once, and the combined attack of various attacks can not be resisted. The invention relates to the digital watermark method which is characterized in that different types of watermark information are embedded into a carrier image, specifically comprising the steps of embedding and extracting the watermark; the watermark can be converted into binary information with a specific length; the watermark becomes a 'pseudo watermark' by coding, correcting errors and adding a watermark head; then, the obtained 'pseudo watermark' is embedded into the carrier image; in the extraction process, the 'pseudo watermark' is obtained firstly; and then an original watermark is obtained. With the method, clipping attack and image scaling attack can be effectively resisted.

The invention belongs to an information safety, multimedia information processing field, in particular, the invention is a new digital watermark method for protecting copyright of a music production, mainly comprises a synchronization code, a watermark embedding and detecting. At first, the invention performs information embedding by segmenting the music production and dividing each music data segment into two front and rear portions. The synchronization code is embeded into the front portion by modifying a statistical average value of a plurality of sampled values, and the rear portion is used for embedding watermark information, the embedding process comprises: performing DWT on the music data segments, then performing DCT on low-frequency coefficients in a wavelet field, embedding the encrypted watermark information in the low / middle frequency coefficients of the DCT field by a self-adaptive quantization method, finally obtaining the digital music production with embeded watermark information by a reverse converting process and re-combining the music data segments. Detecting the digital watermark is a reverse process of the embedding process. The invention can be used in music productions of different types independent of adjustment of a threshold value.