JP2009017092A - Program for reading information embedded in figure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a program which clarifies that embedded information exists and reads the information embedded in an elaborately-designed figure. <P>SOLUTION: This is an information reading program for reading the embedded information from a figure embedded with information and is executed on a mobile terminal device having a camera portion and a display portion, and the figure consists of a main part and an extended part. This figure information read program includes a main part region recognizing means for recognizing the main part region of the figure captured by the camera portion, an extended part region recognizing means for recognizing the extended part region of the figure captured by the camera portion, a start position setting means for setting the starting position of reading the embedded information, and an expansion coefficient calculating means for calculating the expansion coefficient from the extended part region. This program makes the mobile terminal serve as an information restoring means for making the embedded information restore by using the calculated expansion coefficient. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a program for reading information encoded as a contour graphic in a graphic such as a logo, a line drawing, or a mark.

  Conventionally, bar codes or two-dimensional codes have been used as information carriers for production management, product management, and the like. In addition, since the mobile phone is equipped with a two-dimensional code reading function, URL information is given to the two-dimensional code to guide the user to a campaign site performed by the manufacturer. It has come to be used as one. However, the barcode and the two-dimensional code have poor design properties, and there is a problem that the design properties are impaired when the barcode, the catalog, and the information magazine are published.

Patent Document 1 discloses a technique for improving and enhancing a design shape by dispersing and arranging error correction code figures of a two-dimensional code.

On the other hand, as a technique that does not impair the designability, for example, there is a method of embedding information in a picture or the like using a digital watermark technique.
Patent Document 2 discloses a technique for embedding information in a printed line drawing using a fine line that cannot be recognized by humans using a Fourier function.
Japanese Patent Laying-Open No. 2006-235672 (paragraph 0022, FIG. 6) JP 2003-246134 A (paragraph 0058-paragraph 0061, FIG. 1-3)

By the way, in the technique of Patent Document 1, since the shape of the two-dimensional code is a combination of black and white rectangular figures, there is a limit to the improvement in design.
Further, in the technique of Patent Document 2, there is a problem that the user cannot visually recognize that the information is embedded as the purpose of the digital watermark. was there.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a program for reading information embedded in a figure having a design property that makes it clear that embedded information exists. Is to provide.

The present invention solves the above problems by the following means. That is, the invention of claim 1 is an information reading program for reading embedded information from a figure in which information is embedded, and the information reading program is executed by a portable terminal device having a camera unit and a display unit. The figure is composed of a body part and an extension part, and recognizes a body part area recognition means for recognizing the body part area of the figure photographed by the camera part, and recognizes the extension part area of the figure photographed by the camera part. The extension part area recognition means, the start position setting means for setting the reading start position of the embedded information, the expansion coefficient calculation means for calculating the expansion coefficient from the extension part area, and the embedded expansion using the calculated expansion coefficient A graphic information reading program which causes a portable terminal to function as information restoring means for restoring information.

Here, the information embedded in the extended part of the figure can be taken out.

According to a second aspect of the present invention, the main body region recognizing means obtains the color of the flat portion of the main body region of the graphic photographed by the camera unit from the vicinity of the position designated by the cursor, thereby The graphic information reading program according to claim 1, wherein a partial area is recognized.

According to a third aspect of the present invention, when the resolution of the figure to be photographed is not sufficiently obtained, the camera unit shoots the figure divided into a plurality of parts, and the body part region recognition unit and the extension part region recognition unit are 2. The graphic information reading program according to claim 1, wherein a relative figure is determined by pattern matching and a photographed figure is obtained by combining them.

The invention according to claim 4 functions as a center of gravity calculating means for calculating the center of gravity of the main body of the figure.

The invention according to claim 5 is the graphic information reading program according to any one of claims 1 to 4, wherein the expansion coefficient is a Fourier expansion coefficient.

The invention according to claim 6 is characterized in that the start position setting means sets the read start position of the embedded information by using the lowest frequency coefficient of the Fourier expansion coefficient of the photographed figure as a constant. The graphic information reading program described in the above.

The invention according to claim 7 is the graphic information reading program according to any one of claims 1 to 4, wherein the expansion coefficient is a coefficient of a Schauder expansion formula.

According to an eighth aspect of the present invention, the figure is composed of a main body part and an outer extension part, a boundary exists between the main body part and the outer extension part, and the main body part is a convex figure. Of the boundaries of the extension part, the boundary opposite to the body part boundary has an extension line, and a half line extending from a point in the body part region of the figure intersects the boundary line and the extension line The graphic information reading program according to any one of claims 1 to 7, wherein the embedded information can be restored from the length information of the line segment and the distance information from the start position. is there.

The invention according to claim 9 is characterized in that the main part of the figure is formed by a flat net by a single net percentage, and the outer extension part is formed by a flat net that can be distinguished from the main part flat net. The graphic information reading program described in the above.

The invention of claim 10
The graphic reading start position is formed by providing a portion having an extended portion contour of a certain length parallel to the main body contour of the photographed graphic when using a Chowder expansion type coefficient as the expansion coefficient. A graphic information reading program according to claim 8 or 9, wherein:

According to the present invention,
(1) Information embedded from a designable figure can be read.
(2) The embedded information can be read from a graphic that can clearly indicate that the embedded information exists.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
FIG. 1 shows a figure 100 with information embedded using the technique of the present invention.
The figure 100 includes a main body portion 104 that is a design mark and an extended portion 106 in which information is embedded.
A boundary line 105 is drawn between the main body part 104 and the extended part 106 so that the boundary between the main body part 104 and the extended part 106 in which information is embedded can be seen.
The main body 104 is printed with a uniform halftone dot 101 (hereinafter, a flat halftone 101). When the figure 100 is photographed with a camera or the like and image processing is performed, the two are separated from each other by a sufficient color space so that the flat screen 101 and the boundary line 105 of the main body 104 can be distinguished. A line drawing 103 may be drawn on the main body 104 as an element constituting the design of the mark.
At this time, it is assumed that there is a sufficient distance in the color space between the line drawing 103 and the flat screen 101 of the main body 104. An extension line 109 is drawn on the extension part 106 of the figure, and the shape of the extension part 106 is determined. A flat net 107 is printed on the extended portion 106.
The shape of the extended line 109 is determined by the embedded information 702, and the embedded information 702 can be restored from the shape of the extended line 109.

  FIG. 2 is a diagram for explaining how information is extracted from a graphic according to the present invention. On the print medium 300, a graphic 100 in which information is embedded by the method of the present invention is printed. The mobile phone 200 includes a mobile application program for extracting information from the image of the graphic 100 taken with the camera.

When the mobile application is activated on the mobile phone 200, an instruction is displayed on the display unit 221 of the mobile phone 200 to “move the cursor to the flat screen of the main body of the figure”. At the same time, the cursor 203 is displayed on the display unit 221 of the mobile phone.
First, the color information of the flat net 101 of the figure main body is acquired. The user positions the cursor 203 on the flat screen 101 of the graphic main body displayed on the display unit 221 of the mobile phone 200, and presses the enter (= shoot) button to perform shooting. The mobile phone 200 starts shooting from the cursor position. The color information of the flat screen 101 of the figure main body is acquired (FIG. 2 (1)).

  Next, the mobile phone 200 displays an instruction on the screen so as to “shoot the entire extension part”. The portable user holds the camera so that the entire extension part 106 of the figure is in the field of view for shooting, places the cursor 203 of the display part 221 of the cellular phone almost at the center of the extension part 106 of the figure, and presses the enter button to take a picture. (Same as (2)).

At this time, if an image cannot be taken with sufficient resolution, the mobile phone 200 displays an instruction to “zoom up and take a plurality of images”. When the mobile user divides and shoots the graphic extension 106, the mobile phone 200 takes out the extension 106 from the divided photographic images and combines them.

The cellular phone 200 reads (= decodes) the information embedded in the photographed extension part 106 and displays the reading result on the display unit 221 ((3)).

FIG. 3 is a detailed explanatory diagram of a figure in which information according to the present invention is embedded.
The figure main body 104 is a convex figure such as a circle.
Incidentally, a convex figure refers to a figure in which all line segments connecting any two points in the figure are included in the figure.
In a figure in which the main body part is a convex figure, all the half lines 110 extending radially from one point (for example, the center of gravity) of the main body part 104 intersect with the boundary line 105 at one point.

When the inclination angle of the half line 110 is “θ”, the value of the distance between the extension line 109 and the boundary line 105 is “h”.
Here, the relationship between the inclination angle “θ” and the distance value “h” will be described.
The embedded information 702 is divided into a plurality of pieces of information, and the divided information and the angle “θ” are associated with each other. A distance value “h” is calculated using the division information. A list in which “θ” is associated with “h” calculated from the divided information (details will be described later) is created. Using this list of “h” and “θ”, an extended part of the figure is generated at a position of a distance “h” from the intersection of the boundary line 105 on the half line 110 of the inclination angle “θ” of FIG. The

In this way, the extension part 106 in which information is embedded is created.

The information embedded in the extension part 106 can be associated with the inclination angle “θ” of the half line 110 and the distance value “h” is read to calculate the division information for each “θ”. Furthermore, by reconstructing the calculated division information, the embedded information can be restored and read.

FIG. 4 is a developed view of the extended portion.
FIG. 6 is a diagram in which an inclination angle “θ” of a half line 110 and a distance value “h” between an extension line 109 and a boundary line 105 are expressed in an orthogonal coordinate system.

A procedure for creating the extension part 106 using the Fourier expansion coefficient will be described. .
Here, the division information is set in association with the expansion coefficient sequence “β” (details will be described later) of the Fourier expansion.
FIG. 5 to FIG. 7 are diagrams for explaining formulas for calculating the extension line 109 of the figure extension part from the embedded information.

FIG. 5 is an equation for calculating the shape of the extended portion.
“(X (θ), y (θ))” represents the coordinate value of the extension line 109 of the extension part 106.
“R (θ)” indicates the length until the half line extending from the center of gravity of the main body 104 intersects the boundary line 105.
“H (θ)” indicates the length (distance from the boundary line 105 to the extension line 109) of the extension part 106 on the semi-line.

FIG. 6 is a diagram for explaining an expression for calculating the length of the extended portion 106 on the half straight line.
“L” is a feature length obtained from the boundary line 105 and is used as a feature value of the extension for obtaining the width “h” of the extension part. For example, the length of a square side surrounding the figure body 104 is used.
If the calculated expansion value is negative, the extension portion 106 comes to the inside of the main body portion 104, which is not desirable, so that “l” is used so that h (θ) is always a positive value. It is a value for putting on clogs. When the extension 106 is formed using the Fourier expansion coefficient value, it may be considered as a shift value for preventing the main body 104 from becoming hard.
“U” indicates a unit value for reflecting the coefficient value in the figure.
“Β _* ” is a processed expansion coefficient that is encoded by an error correction code, and is composed of an even number. Details of the encoding process using the error correction code will be described later.

FIG. 7 is a diagram for explaining an equation for calculating the feature length “l” obtained from the boundary line 105.
“L ₀ ” is a positive value uniquely determined in advance, and is a value provided to prevent the width h of the extended portion from becoming zero.
In the process of calculating “l”, the expression “min (sigma (β _2i uCOS (θ) + β _{2i + 1} u
SI
N (θ)) ”is calculated by determining the Fourier function that forms the extension 106 and then calculating the value of“ sigma (β _2i uCOS (θ) + β _{2i + 1} uSIN (θ)) ”corresponding to each θ. Can be calculated to find the minimum value.

FIG. 8 is a diagram illustrating a procedure of processing for creating a Fourier expansion expansion coefficient from information 702 embedded in the extension part 106.
The information to be embedded 702 is a byte sequence of “α _i ” composed of 1 byte.
Here, “j” is “0 to (M−1)” when the value of the number of embedded information 702 bytes is “M” bytes.
An identifier 701 is added to the head of the information 702 to be embedded.
The head identifier 701 stores the number of bytes of the information 702 to be embedded (value of the number of bytes = M).

First, error correction coding processing is performed on the head identifier 701 and embedded information 702 to obtain an error correction coded bit string 703 (FIG. 8 (1)).
Here, the well-known Reed-Solomon encoding process or BCH encoding process may be used for the error correction encoding process.
Although an example in which error correction encoding processing is performed on 1-byte information has been shown, information on 2 bytes or more may be subjected to error correction encoding processing if the bytes are fixed.

Next, Fourier expansion coefficients are assigned to the error correction coded bit string 703 every 3 bits to obtain expansion coefficients “β _2i, β _{2i + 1} ” ((2)).
In the Fourier expansion coefficient creation process, since it is necessary to determine the phase corresponding to the polar coordinate angle zero from the obtained image at the time of reading, the values of the expansion coefficients “β ₀ ” and “β ₁ ” Set a predetermined constant. FIG. 8 shows an example in which β _{0 is set} to (111) 2 and β ₁ is set to (000) 2 as indicated by 704. Since the expansion coefficients “β ₀ ” and “β ₁ ” correspond to the coefficient of the lowest frequency, when the information is extracted from the figure in which the information is embedded by setting in this way, the lowest frequency is obtained by the low-pass filter. That is, the phase information can be restored by taking out the term whose wavelength is 2π.
FIG. 8 illustrates expansion coefficients “β _2i, β _{2i + 1} ” in which “3” bits (= κ value) of the error correction coding bit string 703 are included.
Since the number of expansion coefficients “β _2i, β _{2i + 1} ” must be an even number, the bit number 0 is padded as necessary, and the total number of expansion coefficients “β _2i, β _{2i + 1} ” is an even number. To be.

In this way, since a function for determining the shape of the extension part 106 can be determined from the information 702 to be embedded, the extension line 109 may be drawn according to this function.

Note that the same effect can be obtained even by using expansion by an orthogonal polynomial such as a Chebyshev polynomial.

Next, a process for restoring the information 702 to be embedded from the extended gland 109 designed in this way will be described.

FIG. 9 is a flowchart of the graphic embedding information reading process.
(1) Judgment: First, it is judged whether a figure is divided and photographed. (Step S201)
(2) Image data composition: When image data is divided, composition by matching is performed so that a figure including an extended portion is formed into one. (Step S202)
(3) Noise reduction: Noise reduction processing is performed on graphic image data using a noise filter such as a median filter. (Step S203)
(4) Extraction of main body part: Based on the flat mesh color information of the main body part that has been measured in advance, the graphic image data is scanned to extract the area of the main body part 104. Alternatively, an area that can be determined to be the same color by sampling the pixels from the specified position of the main body (= the position specified by the cursor 203) by proximity search may be used. (Step S204)
At this time, position information of the boundary line 105 is also obtained. When obtaining the position information of the boundary line 105, the contour trace 403 of the flat mesh portion 101 of the main body of the figure is performed. By determining whether the contour obtained from the contour trace result is clockwise or counterclockwise, it is possible to identify whether it is a line drawing drawn inside the main body or a main body portion contour (= boundary line).
(5) Determining the center of gravity of the main body: The center of gravity is calculated for the region of the main body 104 to determine the center of gravity coordinates of the main body. (Step S205)
(6) Extraction of the extended portion: The area of the extended portion 106 is extracted by scanning the flat portion graphic image data based on the flat mesh color information of the extended portion measured in advance. At this time, position information of the extended line 109 is also obtained. (Step S206)
Alternatively, the region of the extended portion may be recognized by searching for a flat mesh portion outside the outline of the main body portion and performing similar proximity scanning on the flat mesh portion.
(7) Search for start position: A half line is extended from the body part center-of-gravity coordinates obtained previously, and the thickness “h” of the extension part is obtained from the boundary line 105 and the extension line 109 intersecting with the half line. By applying a low-pass filter to the Fourier expansion function expressing the angle as a parameter, the phase of the lowest frequency (that is, the term of the wavelength 2π) is obtained, and the axis corresponding to the polar angle of zero is set from the phase. (Step S207)
(8) Fourier expansion coefficient determination: Fourier expansion is performed to determine coefficient values. (Step S208)
(9) Bit stream formation: The obtained Fourier expansion coefficients are classified by the system-specific bit length “κ” (in FIG. 8, an example in which κ is set to 3 is shown). Therefore, after removing the expansion coefficients “β ₀ ” and “β ₁ ” used to determine the phase from them, a bit string that is connected in order is synthesized, and the original data is added with a parity bit for error correction to match the bit length Reclassify. In this way, an error correction coded bit string 703 is obtained. (Step S209)
(10) Error correction: An error correction process is performed on the divided error correction coded bit string 703 to generate a decoded bit string. (Step S210)
(11) Embedding information restoration: A value of a specified byte length is read from the head identifier, a specified byte is cut out from the decoded bit string, a byte string is created, and embedded information 701 is obtained. (Step S211)

(Example)
An example of information embedding by the shauder expansion formula will be described.
The Schauder expansion formula is a method of approximating the shape of a curve using a triangle, and even if a defect occurs in a part of a figure, there is an effect that an adverse effect of information restoration due to the defect remains locally. For this reason, even if there is a missing figure, the information of the figure without the missing is correctly restored.

The shouter expansion formula will be described with reference to FIGS. FIG. 10 shows a shouter expansion type.
“A _{k, i} ” is an expansion coefficient, and “F” is a basis function.

FIG. 11 is an explanatory diagram of the shauder expansion coefficient “ _{ak, i} ”.

FIG. 12 is a diagram for explaining a basis function sequence of the Schauder expansion formula.

A method of creating the extension part 106 obtained from the shauder expansion formula using the embedded information 702 will be described.
The technique of assigning the embedding information 702 to the shauder expansion coefficient “a _{k, i} ” is to assign a shauder expansion coefficient for every 3 bits to the error correction coded bit string 703 as in the case of obtaining the Fourier expansion coefficient. The expansion coefficient “a _{k, i} ” is obtained. If the expansion coefficient is determined, the Schauder expansion formula of FIG. 10 can be obtained using the basis function sequence obtained in FIG. The shape of the extended portion 106 can be determined from the shouter deployment type.

Next, a processing flow for reading figure embedding information will be described.

(1) Determination: Image data synthesis: Noise reduction: Extraction of main body part 106: Determination of center of gravity of main body part: Extraction of the extension part 106 is the same as steps S201 to 206 in FIG. (Step S401)
(2) Start position search: As the start position, a portion parallel to the boundary line 105 (that is, the same thickness. For example, the extended line 119 in FIG. 3 is set as the start position (step S402).
(3) Calculation of the shauder expansion coefficient: From the shape of the extension line 109, the calculation of the shauder expansion coefficient is performed 409. (Step S403) (4) Bit string formation: Error correction: The information embedded from the Schauder expansion coefficient is obtained, and the restoration method is performed in the same manner as Steps S209 to 211 in FIG. (Step S404)

Conceptual diagram of figure 100 in which information according to the present invention is embedded The figure explaining a mode that information is extracted from the figure by this invention Detailed explanatory diagram of figure embedded with information according to the present invention Expand the distance value to “h” Formula for calculating the shape of the extension The figure explaining the formula which calculates the length of the extension part on a half line The figure explaining the formula which calculates feature length "l" obtained from the boundary line 105 Procedure for creating a Fourier expansion expansion coefficient from embedded information Process for reading figure-embedding information (Example) Shouter deployment type (Example) Explanatory diagram of the shauder expansion coefficient “a _{k, i} ” (Example) Basis function sequence of the Schauder expansion formula

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Information embedded figure 101 Main part flat net 103 Line drawing 104 Main body part 105 Border line 106 Outer extension part 107 Outer extension flat net 109 Outer extension line 110 Half line 200 extending radially from the center of gravity of the main part 104 Mobile phone 203 Cursor 221 Display unit 300 Print medium 701 First identifier 702 Embedded information 703 Error correction encoded bit string

Claims (10)

An information reading program for reading embedded information from a figure in which information is embedded,
The information reading program is executed by a mobile terminal device having a camera unit and a display unit,
The figure is composed of a main body part and an extension part,
A body part region recognition means for recognizing a body part region of a figure photographed by the camera part;
An extended area recognition means for recognizing an extended area of a graphic photographed by the camera unit;
Start position setting means for setting the reading start position of the embedded information;
An expansion coefficient calculating means for calculating the expansion coefficient from the extension area,
A graphic information reading program for causing a portable terminal to function as information restoring means for restoring information embedded using a calculated expansion coefficient. The main body region recognition means recognizes the main body region of the figure by obtaining the color of the flat part of the main body region of the figure photographed by the camera unit from the vicinity of the position designated by the cursor. The graphic information reading program according to claim 1, wherein: When the resolution of the figure to be photographed is not enough,
The camera unit shoots a figure divided into a plurality of parts,
2. The graphic information according to claim 1, wherein the main body region recognition unit and the extension portion region recognition unit determine their relative positions by pattern matching and combine them to obtain a photographed figure. Reading program. 2. The graphic information reading program according to claim 1, wherein the graphic information reading program functions as a centroid calculating means for calculating the centroid of the main body of the graphic. 5. The graphic information reading program according to claim 1, wherein the expansion coefficient is a Fourier expansion coefficient. 6. The graphic information reading program according to claim 5, wherein the starting position setting means sets a reading start position of embedded information using a coefficient of a lowest frequency of a Fourier expansion coefficient of a photographed graphic as a constant. . The graphic information reading program according to any one of claims 1 to 4, wherein the expansion coefficient is a coefficient of a Schauder expansion formula. The figure is composed of a main body part and an extension part,
The boundary between the main body part and the extension part has a boundary line,
The main body is a convex figure,
Of the boundaries of the outer extension, the boundary opposite to the main body boundary has an extension line,
The embedded information can be restored from the length information of the line segment where the half line extended from the point in the main body area of the figure intersects the boundary line and the extension line, and the distance information from the start position The graphic information reading program according to any one of claims 1 to 7.   9. The graphic information reading program according to claim 8, wherein the main body portion of the graphic is formed by a flat net made of a single net percentage, and the extended portion is formed by a flat net that can be distinguished from the main body flat net. . The reading start position of the figure is
When using the coefficient of the Schauder expansion formula as the expansion coefficient,
10. The graphic information reading program according to claim 8, wherein the graphic information reading program is formed by providing a portion having an extended portion contour of a certain length parallel to the main body contour of the photographed graphic.

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