Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Takashi Katsura

Hisashi Inoue

Kenichi Noridomi

Masataka Ejima

Shinya Kadono Kadono

Kazuhiko Nakamura

Takanori Okada

Kazuhiko Ito

Shiro Iwasaki

Shuichi Ojima

Yuji Shimizu

Yuichi Kawaguchi

Masataka Ozawa

Yoshiro Ogata

Eiichi Hatae

Kazutaka Koyama

Mikio Shimazu

Koji Arimura

Shinichi Tsumori

Shugo Horikami

Koji Sugishita

Akio Miyazaki

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.

Information embedding device and program for changing a number of points that exist on sides of a polygon

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.

Digital watermark-embedding apparatus and method, digital watermark-detecting apparatus and method, and recording medium

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.

Digital watermark-embedding apparatus, digital watermark-embedding method, and recording medium

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.

Digital watermark-embedding apparatus, digital watermark-embedding method, and recording medium having recoded therein a program for performing the digital watermark-embedding method

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.

Reproduction equipment, reproduction equipment specifying equipment, reproduction equipment specifying system and methods and recording media for said equipment and system

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.

Justification authenticating system, personal certificate issuing system, and personal certificate

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 apparatusdivides 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 apparatusextracts 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. The image is divided in to a plurality of blocks composed of a predetermined number of pixels. For each block, an information series embedded in the transform coefficients of MRR representing the same spatial region as the unit block is compared, for verification, with the corresponding authentication data series so that the tamper is determined on a regional basis.

Apparatus and method for embedding information for tamper detection and detecting tamper and recording medium having program for carrying out the method recorded thereon

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.

Digital watermark embedding method, digital watermark extracting method, recording medium, image recording device, and image replaying device

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. This method discourages deciphering of the digital information, suppresses image quality deterioration, and improves the detection rate of watermark data.

Digital information embedding/extracting apparatus and method, and medium including a program for executing the method recorded thereon

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. The mean difference addition portion subjects the replaced quantization value, for each block, to inverse linear quantization using the quantization step-size Q to calculate a mean value M&prime;, and adds a difference DM between the mean value M&prime; and the mean value M to all the transform coefficients in the block. The mean calculation portion calculates a mean value LM of the transform coefficients in the frequency band after the addition of the difference DM. The band synthesis portion reconstructs a signal in which the information has been embedded using the frequency band after the addition of the difference DM and the other frequency bands.

Apparatus for and method of embedding and extracting digital information and medium having program for carrying out the method recorded thereon

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.

Apparatus for and method of embedding and extracting digital information, and medium having program for carrying out the method recorded thereon

A high-pressure sodium lamp is connected to a d.c. power supply through a ballast, to operate it with a current containing a d.c. component. The relation between the ratio l/d of the inter-electrode distance l (mm) to the inner diameter d (mm) of the arc tube of the high-pressure sodium lamp and the sodium vapor pressure P.sub.Na (kPa) in the arc tube is maintained at P.sub.Na .gtoreq.6.0 (l/d-5.8), thus making it possible to operate the high-pressure sodium lamp with a current containing a d.c. component without causing a significant color separation which otherwise might be the result of cataphoresis.

Growing community of inventors

Fukuoka, Japan

Takashi Katsura