Electronic document, genuineness management method for print medium thereof, genuineness management system, program, and program recording medium

• US 20040052400A1
• Filed: 02/28/2003
• Published: 03/18/2004
• Est. Priority Date: 09/13/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yoshiura, Hiroshi, Inomata, Hirofumi, Matsuki, Takeshi, Noyama, Hideo
• Granted Patent: US 7,224,820 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/3236 Details of authentication information generation
• CPC Class Codes: H04N 2201/3281 Encryption; Ciphering

Abstract

A method for managing genuine characteristics of both an electronic document and a print medium comprising: a step for recognizing image data contained in the electronic document; a step for applying an extraction condition of an image feature previously determined and must be considered to the recognized image data to calculate a coordinate set corresponding to a pixel or a set of pixels, constituting the image feature; a step for recognizing at least a coordinate value among coordinate values and pixel color values, corresponding to each of coordinates constituting the coordinate set, and for embedding the recognized coordinate value as a code of a digital watermark into the pixel or the pixel set, constituting the image feature, or into an area in the vicinity; and a step for outputting the electronic document where the digital watermark embedding process operation has been carried out to the print medium.

Claims

1. A genuineness management method for managing genuine characteristics of both an electronic document and a print medium thereof by using a computer, wherein:

said computer executes;

a step for recognizing image data contained in the electronic document;

a step for applying an extraction condition of an image feature which has been previously determined and must be considered to said recognized image data so as to calculate a coordinate set corresponding to either a pixel or a set of pixels, which constitute said image feature;

a step for recognizing at least a coordinate value among coordinate values and pixel color values, which correspond to each of coordinates constituting said coordinate set, and for embedding said recognized coordinate value as a code of a digital watermark into either the pixel or the pixel set, which constitute said image feature, or into an area in the vicinity thereof; and

a step for outputting the electronic document to which said digital watermark embedding process operation has been carried out to the print medium.

2. A genuineness management method as claimed in claim 1, further comprising:

a step for recognizing text data contained in said electronic document;

a step for applying a hash function to said recognized text data so as to produce a hash value originated from the text data;

a step for applying a hash function to at least the coordinate value among the coordinate values and the pixel color values, which correspond to each of the coordinates constituting said coordinate set so as to produce a hash value originated from the image data;

a step for producing a synthesized hash value by synthesizing the hash value originated from said text data with the hash value originated from said image data;

a step for giving a digital signature to said synthesized hash value;

a step for converting said synthesized hash value to which the digital signature has been given into a computer readable visible pattern so as to produce visible certification data; and

a step for applying said visible certification data to said electronic document to which said digital watermark embedding process operation has been executed, and for outputting the resulting electronic document to the print medium.

3. A genuineness management method as claimed in claim 1, further comprising:

a step for recognizing a digital signature contained in said electronic document;

a step for certifying validity of said recognized digital signature;

a step for applying a hash function to attribute information of the digital signature whose validity has been certified so as to produce a hash value originated from the digital signature; and

a step for synthesizing the hash value originated from said digital signature with both the hash value originated from said text data and the hash value originated from said image data so as to produce said synthesized hash value.

4. A genuineness management method as claimed in claim 1, further comprising:

a step for converting attribute information of a digital signature contained in said digital document into digital-signature-visible data; and

a step for applying said digital-signature-visible data to the electronic document to which said digital watermark embedding process operation has been executed, and for outputting the resulting electronic document to the print medium.

5. A genuineness management method as claimed in claim 1, further comprising:

a step for applying a hash function to at least the coordinate value among said coordinate values and said pixel color values so as to produce a hash value originated from the image data; and

a step for containing said produced hash value in said digital watermark code.

6. A genuineness management method as claimed in claim 1, further comprising:

a step in which said computer owns a storage unit, and executes an image capturing process operation with respect to the print medium to which the electronic document has been outputted;

a step for applying the extraction condition of the image feature which has been previously determined and must be considered to the image data captured by said image capturing process operation so as to calculate a reference coordinate set corresponding to either the pixel or the pixel set, which constitute said image feature;

a step for detecting a digital watermark contained in the image data based upon the respective coordinates which constitute said reference coordinate set so as to recognize said digital watermark coordinate set;

a step for recognizing at least an embedded coordinate value among the embedded coordinate values of said detected digital watermark and pixel color values thereof;

a step for extracting both a reference coordinate and an embedded coordinate value of a digital watermark coordinate in which a coordinate value is located within a predetermined error range so as to produce an embedded coordinate set;

a step for applying a hash function to at least a coordinate value among the coordinate values and the pixel color values, which constitute said embedded coordinate set, so as to produce a hash value originated from the embedded coordinate;

a step for identifying the hash value which is recognized based upon the visible certification data by said capturing process operation with said hash value of the embedded coordinate in order to judge as to whether or not said recognized hash value is made coincident with said hash value originated from said embedding coordinate; and

a step in which if said recognized hash value is made coincident with said hash value as a result of said judgement, then an electronic document containing at least said image data is stored into said storage unit.

7. A genuineness management method as claimed in claim 6, further comprising:

a step for applying hash functions to both text data and a digital signature, respectively, which are captured by said image capturing process operation, so as to produce hash values; and

a step for synthesizing both the produced hash value originated from the text data and the produced hash value originated from the digital signature with said hash value originated from said embedded coordinate in order to produce a synthesized hash value originated from said captured data; and

a step for identifying said synthesized hash value originated from said captured data with said hash value recognized by said visible certification data in order to judge as to whether or not said synthesized hash value is made coincident with said recognized hash value.

8. A genuineness management method as claimed in claim 6, further comprising:

a step in which when said image capturing process operation is executed, formats of the respective data contained in said print medium to be captured are recognized;

a step for identifying said recognized format with a table which determines formats to be captured as image data;

a step for recognizing the image data to be captured by the image capturing process operation as a result of said identification; and

a step for capturing an image with respect to said recognized image data.

9. A genuineness management system for managing genuine characteristics of both an electronic document and a print medium, comprising:

means for recognizing image data contained in the electronic document;

means for applying an extraction condition of an image feature which has been previously determined and must be considered to said recognized image data so as to calculate a coordinate set corresponding to either a pixel or a set of pixels, which constitute said image feature;

means for recognizing at least a coordinate value among coordinate values and pixel color values, which correspond to each of coordinates constituting said coordinate set, and for embedding said recognized coordinate value as a code of a digital watermark into either the pixel or the pixel set, which constitute said image feature, or into an area in the vicinity thereof; and

means for outputting the electronic document to which said digital watermark embedding process operation has been carried out to the print medium.

10. A storage medium for storing thereinto a program which causes a computer to execute a method of managing genuine characteristics of both an electronic document and a print medium thereof, wherein:

said program causes said computer to execute;

a step for recognizing image data contained in the electronic document;

a step for applying an extraction condition of an image feature which has been previously determined and must be considered to said recognized image data so as to calculate a coordinate set corresponding to either a pixel or a set of pixels, which constitute said image feature;

a step for recognizing at least a coordinate value among coordinate values and pixel color values, which correspond to each of coordinates constituting said coordinate set, and for embedding said recognized coordinate value as a code of a digital watermark into either the pixel or the pixel set, which constitute said image feature, or into an area in the vicinity thereof; and

a step for outputting the electronic document to which said digital watermark embedding process operation has been carried out to the print medium.