Hitachi, Ltd.

Yutaka Kurosu

Hiroshi Yoshiura

Kousuke Anzai

Isao Echizen

Naoko Iwami

Chisato Konno

Tomoyuki Kaji

Hajime Morito

Shinobu Eikawa

Kazunori Nakano

Miki Tanaka

Kazumasa Kita

Ju&nacute;ichi Taguchi

A digital watermark information is extracted from geometrically deformed image without using a calibrating digital watermark. Pixel data at positions predetermined in an X-Y coordinate used when embedding the watermark is extracted from image data in which the digital watermark has been embedded for given pixel data and compared with a reference value to determine whether the watermark has been embedded in the pixel data concerned or not. This processing is repeated until it is confirmed that the information is embedded in the pixel data concerned, while applying geometric deformation to the image data.

Method of extracting digital watermark information and method of judging bit value of digital watermark information

A method and apparatus for embedding information into a target element in which information is to be embedded and a storage medium. The method and apparatus include obtaining plural sets of data values of a plurality of elements, wherein each set of data values is obtained along one direction extending through the target element, determining a strength of embedding information into the target element based on the plural sets of data values obtained, and embedding information into the target element based on the strength determined. The storage medium stores a program which enables embedding information by execution by a computer.

Method of judging digital watermark information

There is provided a steganographic system which can dispense with an original image during extraction of watermark by determining a position at which an optimum space dependent physical quantity is embedded as a watermark complying with an image such that the picture quality can be prevented from being deteriorated, embedding watermark information in the image, generating information such as watermark embedding position information and receiving a watermark embedded image and watermark embedded position information to extract watermark information.

Steganographic system, method, program and storage medium therefor

A digital watermark information judging method is provided for detecting digital watermark information which is embedded in at least one element of digital data by altering at least one data value of the element. The method first estimates the data value of the element by using data values of at least two neighboring elements of data located near the element, then compares the estimated data value with an actual data value of the element to detect the amount of the alteration, and judges the presence and value of the digital watermark information based on the amount of the alteration.

A recording device which is capable of preventing alteration of a generated digital picture data and suitable for improving the reliability of the digital picture data as an evidence. The recording device includes a related information embedding unit for embedding a related information on the digital picture data stored in a related information storing unit in the digital picture data obtained by a picture receiving unit by means of the digital watermarking technique, a digital signature generating unit for generating a digital signature of the digital picture data in which the related information has been embedded, and a recording unit for adding the digital signature to the digital picture data in which the related information has been embedded and storing it in a memory unit.

Recording device

According to a digital watermark information extracting method, pixel data located at predetermined positions on X-Y coordinate used when digital watermark information is embedded are extracted from image data, and the data value of the pixel data is compared with a reference value to judge whether the watermark information is embedded in the pixel data concerned. This processing is repetitively executed while a geometrical deformation is applied to the image data until it is confirmed that the information is embedded in the pixel data.

Method of extracting digital watermark information and method of judging but value of digital watermark information

An extraction process includes the steps of carrying out a geometric transformation on a picture being inspected to transform the size of the picture being inspected into a reduced scale of an original picture; creating a plurality of degraded original pictures with different types each obtained as a result of degradation of the original picture; creating a plurality of differential pictures by subtraction of the degraded original pictures with different types from the picture being inspected with a transformed size to cancel degradation components in the picture being inspected with a transformed size; and extracting the information corresponding to the authentication information.

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Yokohama, Japan

Yutaka Kurosu