WO2009093430A1 - Dispositif et procédé de formation de motif entrelacé, et dispositif et procédé de détection de motif entrelacé - Google Patents

Dispositif et procédé de formation de motif entrelacé, et dispositif et procédé de détection de motif entrelacé Download PDF

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Publication number
WO2009093430A1
WO2009093430A1 PCT/JP2009/000164 JP2009000164W WO2009093430A1 WO 2009093430 A1 WO2009093430 A1 WO 2009093430A1 JP 2009000164 W JP2009000164 W JP 2009000164W WO 2009093430 A1 WO2009093430 A1 WO 2009093430A1
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WO
WIPO (PCT)
Prior art keywords
pattern
bit
synchronization
tint block
patterns
Prior art date
Application number
PCT/JP2009/000164
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English (en)
Japanese (ja)
Inventor
Urara Shinmyou
Hiroshi Ito
Mitsuyoshi Suzuki
Ryousuke Fujii
Toyokazu Sugai
Original Assignee
Mitsubishi Electric Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Mitsubishi Electric Corporation filed Critical Mitsubishi Electric Corporation
Priority to JP2009550457A priority Critical patent/JP4827974B2/ja
Publication of WO2009093430A1 publication Critical patent/WO2009093430A1/fr

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G06T1/0021—Image watermarking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32203—Spatial or amplitude domain methods
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
    • H04N1/32203—Spatial or amplitude domain methods
    • H04N1/32208—Spatial or amplitude domain methods involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2201/00—General purpose image data processing
    • G06T2201/005—Image watermarking
    • G06T2201/0051—Embedding of the watermark in the spatial domain

Definitions

  • the present invention relates to a digital watermark method for embedding watermark information in the background of a printed document, and in particular, a tint block pattern forming apparatus and method for forming a tint block pattern by arranging a sync pattern and a bit pattern, and a sync included in the tint block pattern.
  • the present invention relates to a tint block pattern detection apparatus and method for detecting a pattern and a bit pattern.
  • Digital watermarking is a technique for embedding predetermined information in an image or document so as not to be visually understood for the purpose of preventing unauthorized copying or tampering of the image or document.
  • the watermark information can be detected without causing deterioration or disappearance of the watermark information.
  • a document printed on a paper medium like an electronic medium, needs a method of embedding watermark information in a printed document in order to prevent unauthorized copying and falsification of the document.
  • a technique for embedding information expressed by dots called background patterns in a document printed on a paper medium There is a technique for embedding information expressed by dots called background patterns in a document printed on a paper medium.
  • a dot pattern hereinafter referred to as a “synchronization pattern” used when synchronously recovering a dot pattern (hereinafter referred to as a “bit pattern”) indicating bit information (specifying a bit pattern embedding position) is used.
  • This is a technique for embedding in a predetermined position.
  • the synchronization pattern is periodically embedded in the entire document to be printed, and the synchronization of the bit pattern can be recovered by detecting the synchronization pattern periodically embedded.
  • the bit pattern has a predetermined size, a plurality of dots are arranged in the bit pattern, and information is expressed by the dot arrangement method.
  • Patent Document 1 shows an example in which a synchronization pattern composed of three dots is arranged at a predetermined corner of a printed material.
  • the synchronization of the bit pattern can be recovered by detecting the synchronization pattern periodically embedded in the entire document.
  • the printed document with the synchronization pattern embedded is enlarged or reduced by copying or the like, the interval between the three dots that make up the synchronization pattern changes, which makes it difficult to detect the synchronization pattern.
  • There were problems such as being unable to perform pattern synchronization recovery.
  • the present invention has been made in order to solve the above-described problems, and arranges a synchronization pattern capable of recovering the synchronization of a bit pattern even when a printed document is enlarged or reduced by copying or the like.
  • An object of the present invention is to provide a tint block pattern forming apparatus and method capable of forming a tint block pattern.
  • Another object of the present invention is to provide a tint block pattern detection apparatus and method capable of recovering bit pattern synchronization even when a print document is enlarged or reduced by copying or the like.
  • the tint block pattern forming apparatus includes a synchronous pattern determining unit that determines a dot pattern composed of a plurality of straight lines that intersect at one reference point as a synchronous pattern, and a dot pattern that includes a plurality of straight lines, and is mutually linear.
  • Bit pattern determining means for determining a plurality of dot patterns having different inclinations as bit patterns and bit value assigning means for assigning bit values to the plurality of bit patterns determined by the bit pattern determining means, and a tint block pattern forming means Select a bit pattern corresponding to each bit value of the embedded information from among the bit patterns to which the bit value is assigned by the bit value assigning means, arrange the bit patterns, and determine by the synchronization pattern determining means. Place a synchronized pattern to form a tint block pattern In which was to so that.
  • the dot pattern consisting of a plurality of straight lines intersecting at one reference point is determined as a sync pattern, and the dot pattern consisting of a plurality of straight lines, the slopes of which are different from each other.
  • a bit pattern determining unit that determines a plurality of dot patterns as bit patterns, and a bit value assigning unit that assigns bit values to the plurality of bit patterns determined by the bit pattern determining unit.
  • the bit pattern corresponding to each bit value of the embedded information is selected from the bit patterns to which the bit value is assigned by the means, and the bit pattern is arranged, and the synchronization pattern determined by the synchronization pattern determining means is selected.
  • Arranged to form a tint block pattern Even printed document is performed enlargement or reduction in such copying, there is an effect that it is possible to form a background pattern are arranged a synchronization pattern capable of performing synchronization recovery of the bit pattern.
  • FIG. 1 is a block diagram showing a tint block pattern forming apparatus according to Embodiment 1 of the present invention.
  • the reference point determination unit 2 performs a process of determining one reference point where two straight lines constituting the dot pattern intersect.
  • the synchronization pattern determination unit 3 performs a process of determining a dot pattern composed of a plurality of straight lines that intersect at the reference point determined by the reference point determination unit 2 as a synchronization pattern.
  • the dot arrangement interval in this synchronization pattern is the interval determined by the dot interval determination unit 1, and when the dots are arranged without a gap without any gap, the two straight lines constituting the synchronization pattern are continuous.
  • A1 in FIG. 3 is a synchronization pattern composed of continuous straight lines
  • the two lines constituting the synchronization pattern are discontinuous. It becomes a straight line
  • a4 in FIG. 4 is a synchronous pattern composed of discontinuous straight lines.
  • the dot interval determination unit 1, the reference point determination unit 2, and the synchronization pattern determination unit 3 constitute a synchronization pattern determination unit.
  • the bit pattern determination unit 4 performs a process of determining a plurality of dot patterns, each of which is a dot pattern composed of a plurality of straight lines and having different straight line inclinations, as bit patterns.
  • the dot arrangement interval in this bit pattern is the interval determined by the dot interval determination unit 1, and when the dots are arranged without gaps without gaps, the two straight lines constituting the bit pattern are continuous.
  • A2 and a3 in FIG. 3 are bit patterns composed of continuous straight lines
  • the two straight lines constituting the bit pattern are not It becomes a continuous straight line
  • a5 and a6 in FIG. 4 are bit patterns composed of discontinuous straight lines).
  • the slopes of the two straight lines that make up the bit pattern a2 (a5) are different from the slopes of the two straight lines that make up the bit pattern a3 (a6), and the slopes of the two straight lines that make up the synchronization pattern a1 (a4) Is different.
  • the two straight lines constituting the bit patterns a2, a3 (a5, a6) intersect at the reference point determined by the reference point determination unit 2, similarly to the synchronization pattern a1 (a4). It is also possible to use a3 (a5, a6) as a synchronization pattern.
  • the bit pattern determination unit 4 constitutes a bit pattern determination unit.
  • the bit value assigning unit 5 performs a process of assigning bit values to a plurality of bit patterns determined by the bit pattern determining unit 4.
  • the bit value assigning unit 5 constitutes a bit value assigning means.
  • the embedded information storage unit 6 is a memory that stores embedded information embedded in a print document.
  • the copy-forgery-inhibited pattern formation unit 7 selects a bit pattern corresponding to each bit value of the embedded information stored in the embedded information storage unit 6 from the bit patterns to which the bit value is allocated by the bit value allocation unit 5.
  • the bit pattern is arranged, and the sync pattern determined by the sync pattern determining unit 3 is arranged to form a tint block pattern.
  • the embedded information storage unit 6 and the background pattern forming unit 7 constitute a background pattern forming unit.
  • the document data storage unit 8 is a memory that stores document data of a print document.
  • the data synthesizing unit 9 performs processing for synthesizing the document data stored in the document data storage unit 8 and the tint block pattern formed by the tint block pattern forming unit 7 to create a print document.
  • FIG. 2 is a flowchart showing the tint block pattern forming method according to the first embodiment of the present invention.
  • the dot interval determination unit 1 determines the dot arrangement interval in the dot pattern (step ST1).
  • the dot interval determination unit 1 has a man-machine interface function that accepts designation of dot arrangement intervals, and determines the dot arrangement interval as the designated arrangement interval.
  • the dot interval determination unit 1 may include a communication function that receives information indicating the dot arrangement interval from another device, and may determine the dot arrangement interval according to the information.
  • the reference point determination unit 2 determines one reference point where two straight lines constituting a dot pattern (synchronization pattern, bit pattern) described later intersect (step ST2).
  • the reference point determination unit 2 includes a man-machine interface function that accepts designation of an arbitrary reference point, and determines one reference point as a designated point.
  • the reference point determination unit 2 may include a communication function for receiving information indicating a reference point from another device, and determine the reference point according to the information. Or you may make it the reference point determination part 2 determine a reference point at random using a random number etc., for example.
  • the synchronization pattern determination unit 3 draws two straight lines that intersect at the reference point, and determines a dot pattern composed of these straight lines as a synchronization pattern (step ST3).
  • the dot arrangement interval in this dot pattern is the interval determined by the dot interval determination unit 1, and when the dots are arranged without gaps without gaps, the two straight lines constituting the dot pattern are continuous. There will be a straight line.
  • A1 in FIG. 3 shows an example of a synchronization pattern composed of continuous straight lines.
  • the two straight lines constituting the dot pattern are discontinuous straight lines.
  • A4 in FIG. 4 shows an example of a synchronization pattern composed of discontinuous straight lines.
  • the number of straight lines constituting the synchronization pattern is two, but the number of straight lines constituting the synchronization pattern is not limited to two, and any number of straight lines can be used as long as the number is two or more. Good.
  • the bit pattern determination unit 4 determines the number of bit patterns to be created (step ST4). That is, for example, if each bit value of the embedded information is a binary value of “0” or “1”, the bit pattern determining unit 4 determines the number of bit patterns to be created as “2”, If the bit value is three values of “ ⁇ 1”, “0”, or “1”, the number of bit patterns to be created is determined to be “3”. In the first embodiment, the number of bit patterns to be created is determined to be “2” for the sake of simplicity of explanation. Note that the number of bit patterns to be created may be specified by the user such that the bit pattern determination unit 4 has a man-machine interface function.
  • the bit pattern determination unit 4 determines the number of bit patterns to be created to be “2”, the bit pattern determination unit 4 randomly draws two straight lines that intersect at one reference point determined by the reference point determination unit 2, and is a dot composed of two straight lines.
  • the pattern is determined to be a bit pattern (step ST5).
  • the bit pattern determining unit 4 determines two bit patterns, but the straight lines are appropriately selected and drawn so that the slopes of the straight lines constituting the two bit patterns are different from each other.
  • the arrangement interval of the dots in the bit pattern is an interval determined by the dot interval determination unit 1, and when the dots are arranged without a gap without any gap, the two straight lines constituting the bit pattern are continuous.
  • A2 and a3 in FIG. 3 are bit patterns composed of continuous straight lines
  • the two straight lines constituting the bit pattern are not It becomes a continuous straight line
  • a5 and a6 in FIG. 4 are bit patterns composed of discontinuous straight lines).
  • the slopes of the two straight lines that make up the bit pattern a2 (a5) are different from the slopes of the two straight lines that make up the bit pattern a3 (a6), and that the two straight lines that make up the synchronization pattern a1 (a4) It is also different from the inclination. Further, the two straight lines constituting the bit patterns a2 and a3 (a5 and a6) intersect at the reference point determined by the reference point determination unit 2, similarly to the synchronization pattern a1 (a4). For this reason, it is also possible to use the bit patterns a2, a3 (a5, a6) as the synchronization pattern.
  • bit patterns a2, a3 (a5, a6) are shown as intersecting at the same reference point as the reference point in the synchronization pattern a1 (a4), the synchronization pattern a1 (a4) is shown. ) May be crossed at a reference point different from the reference point.
  • bit pattern determination unit 4 determines a plurality of bit patterns
  • the bit value allocation unit 5 performs a process of allocating bit values to the plurality of bit patterns (step ST6).
  • bit patterns a2, a3 (a5, a6) are created, for example, a bit value of “0” is assigned to bit pattern a2 (a5), and a bit value of “1” is assigned to bit pattern a3 (a6).
  • the tint block pattern forming unit 7 responds to each bit value of the embedded information stored in the embedded information storage unit 6 from the bit patterns.
  • Each bit pattern to be selected is selected, the bit pattern is arranged, and the synchronization pattern determined by the synchronization pattern determination unit 3 is arranged to form a tint block pattern (step ST7). That is, as shown in FIG. 5, if the embedding information is “001001101...”, The tint block pattern forming unit 7 arranges the corresponding bit patterns in order from the upper left of the document.
  • Bit pattern a2 (a5) ⁇ bit pattern a2 (a5) ⁇ bit pattern a3 (a6) ⁇ bit pattern a2 (a5) ⁇ bit pattern a2 (a5) ⁇ bit pattern a3 (a6) ⁇ bit pattern a3 (a6) ⁇ bit Pattern a2 (a5) ⁇ bit pattern a3 (a6) ⁇ .
  • the tint block pattern forming unit 7 arranges synchronization patterns at appropriate positions (in the example of FIG. 5, two synchronization patterns are arranged). However, when arranging the bit pattern and the synchronization pattern, the tint block pattern forming unit 7 forms the tint block pattern so that the centers of the patterns are in a lattice pattern. That is, by arranging each pattern at equal intervals in the horizontal direction and the vertical direction, the tint block pattern is formed so that the centers of the patterns are in a lattice shape.
  • the data synthesizing unit 9 synthesizes the tint block pattern with the document data stored in the document data storage unit 8 to create a print document including the tint block pattern. To do.
  • the synchronization pattern determination unit 3 that determines a dot pattern composed of a plurality of straight lines intersecting at one reference point as a synchronization pattern, and the dot pattern composed of a plurality of straight lines
  • a bit pattern determination unit 4 for determining a plurality of dot patterns having different linear slopes as bit patterns, and a bit value allocation for allocating bit values to the plurality of bit patterns determined by the bit pattern determination unit 4 Unit 5 and the copy-forgery-inhibited pattern forming unit 7 selects a bit pattern corresponding to each bit value of the embedded information from the bit patterns to which the bit value is allocated by the bit value allocation unit 5, and the bit pattern And a synchronization pattern determined by the synchronization pattern determination unit 3
  • a copy-forgery-inhibited pattern can be formed in which a synchronization pattern that can recover the synchronization of the bit pattern is arranged.
  • each dot pattern is composed of a continuous straight line.
  • each dot pattern may be composed of a discontinuous line. . That is, if the dot interval is changed as necessary, it can be applied to various applications.
  • the bit pattern determination unit 4 has been described as determining a bit pattern consisting of a plurality of straight lines as a bit pattern.
  • a dot pattern consisting of a plurality of curves may be determined as a bit pattern. . Specifically, it is as follows.
  • the dot interval determination unit 1 determines the dot arrangement interval in the dot pattern, as in the first embodiment (step ST1). If the interval determined by the dot interval determining unit 1 is such that the dots are arranged without a gap, two straight lines / curves constituting a dot pattern (synchronization pattern, bit pattern) described later are continuous straight lines. (See FIG. 6). On the other hand, if the interval determined by the dot interval determination unit 1 is an interval at which dots are arranged in a jump, two straight lines / curves constituting a dot pattern (synchronization pattern, bit pattern) described later are discontinuous straight lines. (See FIG. 7).
  • the reference point determination unit 2 determines one reference point where two straight lines constituting the synchronization pattern intersect (step ST2).
  • the synchronization pattern determination unit 3 draws two straight lines that intersect at the reference point and synchronizes the dot pattern formed by these straight lines, as in the first embodiment.
  • the pattern is determined (step ST3).
  • the dot arrangement interval in this dot pattern is the interval determined by the dot interval determination unit 1, and when the dots are arranged without gaps without gaps, the two straight lines constituting the dot pattern are continuous. There will be a straight line.
  • B1 of FIG. 6 has shown an example of the synchronous pattern comprised by the straight line with continuity.
  • the two straight lines constituting the dot pattern are discontinuous straight lines.
  • B4 in FIG. 7 shows an example of a synchronization pattern composed of discontinuous straight lines.
  • the number of straight lines constituting the synchronization pattern is two, but the number of straight lines constituting the synchronization pattern is not limited to two, and any number of straight lines can be used as long as the number is two or more. Good.
  • the bit pattern determination unit 4 determines the number of bit patterns to be created as in the first embodiment (step ST4). That is, for example, if each bit value of the embedded information is a binary value of “0” or “1”, the bit pattern determining unit 4 determines the number of bit patterns to be created as “2”, If the bit value is three values of “ ⁇ 1”, “0”, or “1”, the number of bit patterns to be created is determined to be “3”. In the second embodiment, it is assumed that the number of bit patterns to be created is “2” for the sake of simplicity.
  • the dot pattern is composed of two curves, and the two dot patterns having different tangent slopes at the midpoint of the curve. Is determined as a bit pattern (step ST5). Specifically, the bit pattern is determined as follows. Randomly determine three points, draw one curve connecting the three points, determine three points randomly, draw one curve connecting the three points, and consist of two curves The dot pattern is determined as a bit pattern.
  • the arrangement interval of the dots in the bit pattern is an interval determined by the dot interval determination unit 1, and when the dots are arranged without gaps without gaps, the two curves constituting the bit pattern are continuous. (B2 and b3 in FIG.
  • bit patterns made up of continuous curves when dots are arranged at intervals, the two curves that make up the bit pattern are not It becomes a continuous curve (b5 and b6 in FIG. 7 are bit patterns made up of discontinuous curves). Note that the slope of the tangent of the midpoint between the two curves constituting the bit pattern b2 (b5) is different from the slope of the tangent of the midpoint of the two curves constituting the bit pattern b3 (b6).
  • bit value allocation unit 5 performs a process of allocating bit values to the plurality of bit patterns as in the first embodiment (step ST6).
  • bit patterns b2, b3 (b5, b6) are created, for example, a bit value of “0” is assigned to bit pattern b2 (b5), and a bit value of “1” is assigned to bit pattern b3 (b6).
  • the tint block pattern formation unit 7 stores the bit patterns in the embedded information storage unit 6 from among those bit patterns as in the first embodiment. A bit pattern corresponding to each bit value of the embedded information is selected, the bit pattern is arranged, and the synchronization pattern determined by the synchronization pattern determination unit 3 is arranged to form a tint block pattern (step ST7). ). That is, as shown in FIG. 8, if the embedding information is “001001101...”, The tint block pattern forming unit 7 arranges the corresponding bit patterns in order from the upper left of the document.
  • Bit pattern b2 (b5) ⁇ bit pattern b2 (b5) ⁇ bit pattern b3 (b6) ⁇ bit pattern b2 (b5) ⁇ bit pattern b2 (b5) ⁇ bit pattern b3 (b6) ⁇ bit pattern b3 (b6) ⁇ bit Pattern b2 (b5) ⁇ bit pattern b3 (b6) ⁇ .
  • the tint block pattern forming unit 7 arranges synchronization patterns at appropriate positions (in the example of FIG. 8, two synchronization patterns are arranged). However, when arranging the bit pattern and the synchronization pattern, the tint block pattern forming unit 7 forms the tint block pattern so that the centers of the patterns are in a lattice pattern. That is, by arranging each pattern at equal intervals in the horizontal direction and the vertical direction, the tint block pattern is formed so that the centers of the patterns are in a lattice shape.
  • the data synthesizing unit 9 synthesizes the tint block pattern with the document data stored in the document data storage unit 8 to form the tint block pattern. Create a printed document that contains.
  • the dot pattern consisting of a plurality of straight lines intersecting at one reference point is determined as a sync pattern, and the dot pattern consisting of a plurality of curves is used.
  • the bit pattern allocating unit 7 selects a bit pattern corresponding to each bit value of the embedded information from the bit patterns to which the bit value allocating unit 5 has allocated the bit value.
  • the bit pattern is arranged, and the synchronization pattern determined by the synchronization pattern determination unit 3 is arranged.
  • a copy-forgery-inhibited pattern is formed in which a synchronization pattern that can recover the synchronization of the bit pattern is arranged even if the print document is enlarged or reduced by copying or the like. There is an effect that can be.
  • each dot pattern is composed of a continuous curve. Conversely, if it is necessary to make it inconspicuous, each dot pattern may be composed of a discontinuous curve. . That is, if the dot interval is changed as necessary, it can be applied to various applications.
  • the bit pattern determining unit 4 determines a dot pattern composed of two straight lines as a bit pattern
  • the bit pattern determining unit 4 converts the dot pattern composed of two curves into a bit pattern.
  • the bit pattern determining unit 4 accepts designation of the type of bit pattern and determines either a dot pattern consisting of two straight lines or a dot pattern consisting of two curves as a bit pattern. You may make it do.
  • FIG. 9 is a block diagram showing a tint block pattern detection apparatus according to Embodiment 4 of the present invention.
  • the synchronization pattern position specifying unit 11 extracts a tint block pattern from a printed document including the tint block pattern, and the tint block pattern is detected.
  • a process of specifying the position of the synchronization pattern included in the pattern is performed.
  • the reference point extraction unit 12 performs a process of extracting a reference point where a plurality of straight lines constituting the synchronization pattern whose position is specified by the synchronization pattern position specifying unit 11 intersects.
  • the synchronization pattern position specifying unit 11 and the reference point extracting unit 12 constitute extraction means.
  • the synchronization recovery unit 13 performs a process of recovering the bit pattern included in the tint block pattern from the position of the reference point extracted by the reference point extraction unit 12 (a process for specifying the position of the bit pattern).
  • the synchronization recovery unit 13 constitutes synchronization recovery means.
  • the correspondence storage memory 14 is a memory that stores the correspondence between bit values and bit patterns.
  • the embedded information identification unit 15 refers to the correspondence between the bit value and the bit pattern stored in the correspondence storage memory 14 and identifies the bit value assigned to the bit pattern recovered by the synchronization recovery unit 13. Then, the process of specifying the embedded information consisting of the bit value is performed.
  • the correspondence relationship storage memory 14 and the embedded information specifying unit 15 constitute embedded information specifying means.
  • FIG. 10 is a flowchart showing a tint block pattern detection method according to Embodiment 4 of the present invention.
  • the synchronization pattern position specifying unit 11 stores in advance an image of the tint block pattern formed by the tint block pattern forming apparatus of FIG. 1 and performs a reading process of a print document created by the tint block pattern forming apparatus of FIG.
  • the synchronization pattern position specifying unit 11 extracts a copy-forgery-inhibited pattern from the print document and specifies the position of the synchronization pattern included in the copy-forgery-inhibited pattern. (Step ST11).
  • the synchronization pattern position specifying unit 11 determines a position having a high correlation with the synchronization pattern by obtaining a correlation of the synchronization pattern with the tint block pattern and examining a position where the correlation value exceeds a certain threshold value.
  • FIG. 11 shows an example in which the synchronization pattern a4 of FIG. 4 is included in the background pattern and the position of the synchronization pattern a4 is specified.
  • the reference point extraction unit 12 intersects two straight lines constituting the synchronization pattern, that is, two points A reference point where the straight lines intersect is extracted (step ST12).
  • the synchronization recovery unit 13 recovers the bit pattern included in the tint block pattern from the position of the reference point (step ST13). That is, the position of the bit pattern included in the tint block pattern is specified from the position of the reference point.
  • the embedded information specifying unit 15 refers to the correspondence between the bit value and the bit pattern stored in the correspondence storage memory 14 (bit The correspondence relationship between the value and the bit pattern is an assignment result of the bit value assigning unit 5 in FIG. 1 and is preliminarily obtained from the bit value assigning unit 5), and is assigned to the recovered bit pattern.
  • a bit value is specified, and embedded information consisting of the bit value is specified (step ST14). That is, the embedding information specifying unit 15 divides the background pattern into blocks, extracts a bit pattern using correlation or the like for each block, specifies a bit value corresponding to the bit pattern, and embeds information including the bit value. Is identified.
  • the synchronization pattern position specifying unit 11 for specifying the position of the synchronization pattern included in the tint block pattern and the two straight lines constituting the synchronization pattern are provided.
  • a reference point extraction unit 12 that extracts intersecting reference points, and a synchronization recovery unit 13 that synchronously recovers the bit pattern included in the tint block pattern from the position of the reference point extracted by the reference point extraction unit 12, Since the embedded information specifying unit 15 is configured to specify the embedded information from the bit values assigned to the bit pattern recovered by the synchronization recovery unit 13, even if the print document is enlarged or reduced by copying or the like Thus, the bit pattern synchronization recovery can be performed.
  • the synchronization pattern position can be identified and the reference point of the synchronization pattern can be extracted, so the bit pattern synchronization can be performed from the position information of the reference point. Recovery can be done. Further, after the synchronization is recovered, the bit pattern can be identified by using correlation or the like, and the bit value assigned to the bit pattern can be specified.
  • Embodiment 5 FIG.
  • the reference point extraction unit 12 extracts the reference point where the two straight lines constituting the synchronization pattern intersect.
  • the reference point extraction unit 12 determines the center point of the synchronization pattern.
  • the synchronization recovery unit 13 may extract the bit pattern included in the tint block pattern from the position of the center point of the synchronization pattern, and the same effect as in the fourth embodiment can be obtained.
  • the copy-forgery-inhibited pattern forming apparatus can form a copy-forgery-inhibited pattern having a synchronization pattern that can recover the synchronization of the bit pattern even when the print document is enlarged or reduced by copying or the like.
  • the synchronization pattern determining means, the bit pattern determining means, and the bit value assigning means are provided, and the embedded pattern information is selected from the bit patterns to which the bit value assigning means has assigned the bit value by the tint block pattern forming means.
  • the bit pattern corresponding to each bit value is selected and arranged so that the sync pattern is arranged by the sync pattern determining means to form the copy-forgery-inhibited pattern.

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Abstract

L'invention concerne une section de détermination de motif de synchronisation (3) appropriée pour déterminer un motif de points composé d'une pluralité de lignes droites qui se croisent en un point de référence en tant que motif de synchronisation et une section de détermination de motif de bits (4) appropriée pour déterminer une pluralité de motifs de points en tant que motifs de bits, les motifs de points étant composés d'une pluralité de lignes droites et les pentes des lignes droites différant les unes des autres. Les motifs de bits correspondant aux valeurs binaires d'informations intégrées sont sélectionnés parmi la pluralité de motifs de bits et sont agencés. Le motif de synchronisation est également agencé pour former un motif entrelacé.
PCT/JP2009/000164 2008-01-24 2009-01-19 Dispositif et procédé de formation de motif entrelacé, et dispositif et procédé de détection de motif entrelacé WO2009093430A1 (fr)

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US5706099A (en) * 1995-06-05 1998-01-06 Xerox Corporation Method and apparatus for generating serpentine halftone images
JP2004530227A (ja) * 2001-06-07 2004-09-30 ヒューレット・パッカード・カンパニー グラフィカルバーコードの基準目印パターン
JP2006303807A (ja) * 2005-04-19 2006-11-02 Sharp Corp 電子透かし埋め込み装置、電子透かし埋め込み方法、その方法をコンピュータに実現するプログラム、そのプログラムを記録した機械読取可能な記録媒体および印刷物

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US5706099A (en) * 1995-06-05 1998-01-06 Xerox Corporation Method and apparatus for generating serpentine halftone images
JP2004530227A (ja) * 2001-06-07 2004-09-30 ヒューレット・パッカード・カンパニー グラフィカルバーコードの基準目印パターン
JP2006303807A (ja) * 2005-04-19 2006-11-02 Sharp Corp 電子透かし埋め込み装置、電子透かし埋め込み方法、その方法をコンピュータに実現するプログラム、そのプログラムを記録した機械読取可能な記録媒体および印刷物

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