Abstract: Information embedding is performed by extracting vertices constituting a polygon from vector data, and changing a number of points that exist on sides of the polygon based on embedment information. Further, information reading is performed by extracting points existing on the sides of the polygon from the embedment information and embedded vector data, and by reading the embedment information according to a predetermined rule.

Abstract: A digital image signal is divided into blocks. Each of the divided blocks is subjected to orthogonal transformation. As a result, the divided blocks are transformed into several frequency components. One or more frequency components are selected in accordance with a characteristic amount that is extracted from the several frequency components. Values of the selected frequency components are operated under a predetermined rule in accordance with an embedment signal that is generated from embedment information.

Abstract: A characteristic amount is retained and calculated from an entered video signal. Embedment intensity is retained and calculated from the retained characteristic amount. Embedment information is embedded as digital watermarks into the entered video signal in accordance with the retained embedment intensity of the previous frame or field that is located at a position earlier in time than a target image subject to digital watermark embedment. As a result, an output signal of video having the digital watermarks embedded therein is produced. The digital watermarks are embedded into the target image with reference to another image located at a position earlier in time than the target image. Such digital watermark embedment suppresses a delay in output of an output image with reference to an input image.

Abstract: Information embedding is performed by extracting vertices composing a polygon from vector data, and changing the number of points that exist on the sides of the polygon based on the embedment information. Information reading is performed by extracting points existing on the sides of the polygon from the embedment information embedded vector data, and reading the embedment information according to the predetermined rule.

Abstract: An input image is divided into local regions, each of which is formed by a macro block. An embedment intensity is determined for each of the local regions by using a calculated characteristic amount and a compression bit rate. Digital watermarks are embedded at the determined embedment intensity into the input image at each of the local regions thereof. The input image is encoded, thereby providing a compressed bit stream that has the digital watermarks embedded therein.

Abstract: A reproduction equipment converts an identification code of the reproduction equipment into a plurality of signal sequences using a correspondence table and embeds the obtained plurality of signal sequences in AV signals as a digital watermark. A reproduction equipment specifying equipment compares correlation values of the AV signals, containing the digital watermark embedded therein with all signal sequences contained in a correspondence table. A comparison of the correlation values with a previously set threshold value determines the embedded signal sequences and the identification code of the reproduction equipment which may be extracted.

Abstract: A justification/authentication personal certificate system stores in a remote database a counterpart of an identifier and a digital watermark contained in the personal certificate. The personal certificate includes the digital watermark embedded in an authentic image such as a facial photograph, a retinal scan, or a fingerprint. When the personal certificate is used, the authentic image is read from the personal certificate, and the digital watermark information is extracted. The digital watermark information and the identifier are compared with the counterparts stored in the database. If the extracted digital watermark information is identical to the information in the database, then the personal certificate is judged to be unjustifiable. In one embodiment, at least one of the identifier and digital watermark are changed each time the system justifies the personal certificate.

Abstract: An object of the present invention is to provide an information embedding/tamper detecting apparatus and method capable of distinguishing between changes caused by image processing and intentional image tampering, and further capable of localizing, on a regional basis, a tampered position on an image. A tamper-detection-information embedding apparatus 1 divides the image into a plurality of frequency bands to obtain transform coefficients, and then generates a pseudo-random number series by using key data, and further generates authentication data. The key data and the authentication data are embedded in the transform coefficients of MRA and MRR, respectively. the image in which the information is embedded is reconstructed by using MRA and MRR. A tamper-detecting apparatus 2 extracts the key data from MRA obtained by dividing the image into frequency bands and generates the authentication data assumed to have been embedded, and further extracts the embedded information from MRR.

Abstract: Embedding data to be embedded as a digital watermark is acquired. Packing data is formed in which the embedding data is repeatedly connected three times or more sequentially without interval. Real embedding information is formed such that a redundancy bit with a fixed length that is used for an error correction of an information bit is added immediately after the information bit in which the packing data is subdivided into data each having a fixed length. The real embedding information is embedded into the image data itself. The embedding mechanism for the information is not easily understood, and security level is high.

Abstract: In an embedding apparatus, a transform section divides an original image into a plurality of blocks to perform orthogonal transform every block. An embedding section embeds a pseudo-random number sequence mapped with inherent digital information in part of a transform coefficients sequence obtained by the orthogonal transform using a weight sequence. In an extracting apparatus, a calculation section reads transform coefficients sequences for respective blocks from the data including the pseudo-random number sequence embedded therein in a predetermined order, and calculates an inner product between the transform coefficients sequences and a pseudo-random number sequence. A determination section determines that the pseudo-random number sequence has been embedded when the inner product is greater than a predetermined threshold value. A generation section extracts inherent digital information mapped with the determined pseudo-random number sequence.

Abstract: A digital image signal is divided into blocks. Each of the divided blocks is subjected to orthogonal transformation. As a result, the divided blocks are transformed into several frequency components. One or more frequency components are selected in accordance with a characteristic amount that is extracted from the several frequency components. Values of the selected frequency components are operated under a predetermined rule in accordance with an embedment signal that is generated from embedment information.

Abstract: An apparatus for embedding information in a signal includes a band dividing device, a block divider, a quantization portion, a signal replacement portion, a mean difference addition portion, a mean calculation portion, and a band synthesis portion. The band dividing device divides the signal into transform coefficients over a plurality of frequency bands. The block divider divides one frequency band into a plurality of blocks in accordance with a previously determined block size. The quantization portion calculates for each block, a mean value M of the transform coefficients in the block, and subjects the mean value M to linear quantization, using a previously determined quantization step-size Q to calculate a quantization value. The signal replacement portion replaces the quantization value for each block, on the basis of the quantization value and the value of the information to be embedded.

Abstract: A digital information embedding apparatus comprises a band divider, a block divider, a key generator, an information embedder and a band synthesizer. The band divider divides the digital image signal into a plurality of frequency bands to obtain wavelet coefficients. The block divider divides the frequency band in which the digital information is to be embedded into a plurality of blocks in a predetermined block size. The key generator respectively generates secondary keys having different values from a key having a predetermined value using a predetermined function. The information embedder specifies the block in the embedding object region based on each of the generated secondary keys, and respectively embeds the corresponding information composing the digital information in the wavelet coefficients in the specified block in the embedding object region. The band synthesizer reconstructs a digital image signal.

Abstract: A characteristic amount is retained and calculated from an entered video signal. Embedment intensity is retained and calculated from the retained characteristic amount. Embedment information is embedded as digital watermarks into the entered video signal in accordance with the retained embedment intensity of the previous frame or field that is located at a position earlier in time than a target image subject to digital watermark embedment. As a result, an output signal of video having the digital watermarks embedded therein is produced. The digital watermarks are embedded into the target image with reference to another image located at a position earlier in time than the target image. Such digital watermark embedment suppresses a delay in output of an output image with reference to an input image.

Abstract: An object of the present invention is to provide a simple apparatus for and a simple method of embedding and extracting digital information with little clue to a third party as to embedded digital information with less effort, and the embedded information is securely reconstructed thereby. To embed digital information, a band division portion receives a digital image signal, and then divides the same into ten frequency band signals through discrete wavelet transform so as to compute wavelet coefficients. A mapping portion maps inherent digital information to a pseudo-random number string. An information embedding portion embeds the mapped pseudo-random number string in a string structured by every or some of the computed wavelet coefficients in MRR (signals exclusive of an LL3 signal). A band synthesis portion synthesizes the embedded LL3 digital image signal.

Abstract: An input image is divided into local regions, each of which is formed by a macro block. Embedment intensity is determined for each of the local regions using a calculated characteristic amount and a compression bit rate. Digital watermarks are embedded at the determined embedment intensity into the input image at each of the local regions thereof. The input image is encoded, thereby providing a compressed bit stream that has the digital watermarks embedded therein.

Abstract: An apparatus for embedding information in a signal includes a band dividing device, a block divider, a quantization portion, a signal replacement portion, a mean difference addition portion, a mean calculation portion, and a band synthesis portion. The band dividing device divides the signal into transform coefficients over a plurality of frequency bands. The block divider divides one frequency band into a plurality of blocks in accordance with a previously determined block size. The quantization portion calculates for each block, a mean value M of the transform coefficients in the block, and subjects the mean value M to linear quantization, using a previously determined quantization step-size Q to calculate a quantization value. The signal replacement portion replaces the quantization value for each block, on the basis of the quantization value and the value of the information to be embedded.

Abstract: An apparatus for embedding information in a signal includes a band dividing device, a block divider, a quantization portion, a signal replacement portion, a mean difference addition portion, a mean calculation portion, and a band synthesis portion. The band dividing device divides the signal into transform coefficients over a plurality of frequency bands. The block divider divides one frequency band into a plurality of blocks in accordance with a previously determined block size. The quantization portion calculates for each block, a mean value M of the transform coefficients in the block, and subjects the mean value M to linear quantization, using a previously determined quantization step-size Q to calculate a quantization value. The signal replacement portion replaces the quantization value for each block, on the basis of the quantization value and the value of the information to be embedded.

Abstract: A reproduction equipment converts an identification code of the reproduction equipment into a plurality of signal sequences using a correspondence table and embeds the obtained plurality of signal sequences in AV signals as a digital watermark. A reproduction equipment specifying equipment compares correlation values of the AV signals, containing the digital watermark embedded therein with all signal sequences contained in a correspondence table. A comparison of the correlation values with a previously set threshold value determines the embedded signal sequences and the identification code of the reproduction equipment which may be extracted.

Abstract: In an embedding apparatus, an orthogonal transform section 11 divides an original image 1 into a plurality of blocks to perform orthogonal transform every block. An information embedding section 13 embeds a pseudo-random number sequence mapped with inherent digital information in part of a transform coefficients sequence obtained by the orthogonal transform using a weight sequence. In an extracting apparatus, a correlation value calculation section 23 reads sequences of transform coefficients for respective blocks from the data including the pseudo-random number sequence embedded therein in a predetermined order, and calculates an inner product between the sequences of transform coefficients and a pseudo-random number sequence. A pseudo-random number determination section 24 determines that the pseudo-random number sequence has been embedded when the inner product is greater than a predetermine threshold value.