JP7600786B2 - Information recording medium, label, reader, program, and authenticity determination method - Google Patents

Description

The present invention relates to an information recording medium, a label, a reading device, a program, and a method for determining authenticity.

Conventionally, there is electronic watermarking technology that embeds specific information into images, etc. If this technology is used in printed matter, it is possible to embed information at a level that is not visible to the human eye, without compromising the artistic effect of the printed matter. Furthermore, the information embedded in the printed matter can be read by a reading device.

If this embedded information is to be used, for example, to determine authenticity, it is desirable for the embedded information to be difficult to infer from copies. For this reason, technology has been disclosed relating to information recording media that are designed to make the embedded information difficult to infer (for example, Patent Document 1).

JP 2016-93895 A

In the information storage medium described in Patent Document 1, when the information to be read by a reading device is composed of transparent ink, depending on the stacking state of the transparent ink with the lower layer, noise is generated when the information is read by the reading device, making reading difficult.
Also, in order to improve the readability of information composed of transparent ink, methods such as laminating the transparent ink thicker or increasing the density by printing the lower layer in a solid state, etc., have been considered. However, when these methods are adopted, there is a problem in that the visibility of the transparent ink increases when viewed with the naked eye.

The present invention aims to provide an information recording medium etc. that is designed to make information printed on a transparent material difficult to visually recognize and improve the reading accuracy of a reading device.

The present invention solves the above problems by the following means. Note that, for ease of understanding, the following description will be given with reference symbols corresponding to the embodiments of the present invention, but the present invention is not limited to these. Furthermore, the configurations described with reference symbols may be modified as appropriate, and at least a portion of the configurations may be replaced with other configurations.

The first invention is an information recording medium (30) having a first ink layer (31) and a second ink layer (32), the first ink layer and the second ink layer being provided on one surface of a substrate (10) and configured so that the amount of reflected light varies depending on the observation angle, the first ink layer being a first image including a solid image (B1), the second ink layer being a second image formed of a transparent material and including a code having variable information, and an identification area for recognizing the reading area of the code in the second image being formed on the solid image.
A second invention is an information recording medium (30) of the first invention, wherein the first image further includes a pattern image (C1), and at least a portion of the second image is formed superimposed on the pattern image.
A third invention is an information recording medium (30) according to the first or second invention, wherein the second image includes a pattern image (C2).
A fourth invention is an information recording medium (30) according to any one of the first to third inventions, wherein the code is a two-dimensional code, and the identification area of the code is an outer frame of the code.
A fifth invention is an information recording medium (30-2) according to any one of the first to third inventions, wherein the code is a two-dimensional code, and an identification area of the code is a mark indicating the presence of the code.
A sixth invention is an information recording medium according to any one of the first to fifth inventions, wherein the first image includes an image of a code different from that of the second image.
A seventh invention is an information recording medium (30) according to any one of the first to sixth inventions, wherein the first ink layer (31) is formed from a glittering material.
An eighth aspect of the present invention is a label (1) comprising an information recording medium (30) according to any one of the first to seventh aspects of the present invention.
The ninth invention is a reading device (5) that reads an information recording medium (30) of any of the first to seventh inventions, comprising a reading unit (5C), a light-emitting unit (5L) that is provided near the reading unit and emits light, reading means (52) that causes the reading unit to read an image including the second image of the information recording medium while light is being emitted by the light-emitting unit, code area acquisition means (53) that detects the identification area from the image read by the reading means and acquires a code area based on the detected identification area, and code identification means (54) that performs image processing on the code area acquired by the code area acquisition means to identify the code.
A tenth invention is the reading device (5) of the ninth invention, wherein the code identification means (54) divides the code area into cells and identifies the code by performing binarization processing using the luminance value of each cell.
An eleventh invention is a reading device (5) of the tenth invention, wherein the binarization process obtains an average value for each classification based on the luminance value of each cell, and sets the obtained average value as the luminance value of each cell belonging to the classification.
A twelfth invention is a reading device (5) of the tenth or eleventh invention, wherein the binarization process binarizes a single cell using an average value of a luminance value in the single cell and luminance values in each cell located in the vicinity of the single cell.
A thirteenth invention is a reading device (5) according to any one of the ninth to twelfth inventions, wherein the code identification means (54) is a reading device which, when the detected identification area has a shape stored in advance, performs a binarization process corresponding to the shape.
A fourteenth invention is a reading device (5) according to any one of the ninth to thirteenth inventions, comprising an information acquisition means (55) for acquiring the variable information from the code identified by the code identification means (54), and an information output means (56) for outputting information based on the variable information acquired by the information acquisition means to a display unit (67).
The fifteenth invention is a program (61a) executed on a computer (5) for determining the authenticity of an information recording medium (30, 30-2) of any of the first to seventh inventions, which causes the computer to function as a reading means for reading an image including the second image of the information recording medium, a code area acquisition means for detecting the identification area from the read image and acquiring a code area based on the detected identification area, a code identification means for performing image processing on the acquired code area to identify the code, an information acquisition means for acquiring the variable information from the identified code, and an authenticity determination means for determining that the information recording medium is genuine if the variable information is acquired.
The 16th invention is a method for determining the authenticity of an information recording medium (30, 30-2) of any of the first to seventh inventions, comprising the steps of: a computer (5) reading an image including the second image of the information recording medium; detecting the identification area from the read image and acquiring a code area based on the detected identification area; performing image processing on the acquired code area to identify the code; acquiring the variable information from the identified code; and, if the variable information is acquired, determining that the information recording medium is genuine.

The present invention makes it possible to provide an information recording medium that is difficult to visually recognize information printed on a transparent material and that is designed to improve the reading accuracy of a reading device.

FIG. 2 is a diagram for explaining a printed matter according to the embodiment. 1A and 1B are diagrams showing examples of images on an information recording medium according to the present embodiment. 1A to 1C are diagrams showing examples of pattern images of an information recording medium according to the present embodiment. 13A and 13B are diagrams showing other examples of the pattern image of the information recording medium according to the embodiment. 1A and 1B are diagrams for explaining an observation mode based on the structure of an information recording medium according to the present embodiment. 5A and 5B are diagrams for explaining the positional relationship between an illumination light source and a camera when copying a printed matter according to the embodiment. 4 is a diagram showing the positional relationship between an outer camera and a mobile light of a reading device that reads an information recording medium according to the embodiment; FIG. 5A to 5C are diagrams showing examples of reading patterns on an information recording medium by a reading device according to the embodiment. 5A to 5C are diagrams showing specific examples of reading patterns on an information recording medium by the reading device according to the embodiment. FIG. 2 is a functional block diagram of a reading device according to the present embodiment. 5 is a flowchart showing a reading process in the reading device according to the embodiment. 5 is a flowchart showing a code identification process in the reading device according to the present embodiment. 11A and 11B are diagrams for explaining a code identification process in the reading device according to the embodiment. 5A and 5B are diagrams for explaining a binarization process in the reading device according to the embodiment. 5A and 5B are diagrams for explaining a binarization process in the reading device according to the embodiment. 13A and 13B are diagrams showing examples of images of an information recording medium according to a modified embodiment. 13A and 13B are diagrams for explaining a binarization process in a reading device according to a modified embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that this is merely an example, and the technical scope of the present invention is not limited to this example.
(Embodiment)
FIG. 1 is a diagram for explaining a printed matter 1 according to the present embodiment.
The figures shown below, including FIG. 1, are schematic diagrams, and the size and shape of each part are exaggerated or omitted as appropriate for ease of understanding.
In the following description, specific numerical values, shapes, materials, etc. are given, but these can be changed as appropriate.
In the present invention, the term "transparent" refers to a material that transmits at least light of a wavelength to be used.

<Printed material 1>
1A is, for example, a label to be attached to an article. By attaching the printed matter 1 to an article, the printed matter 1 can be used for determining authenticity in product management, distribution, sales, and the like.
1A shows a plan view of a printed matter 1 viewed downward from above in the vertical direction Z. The printed matter 1 includes a base 10 (substrate) and an information recording medium 30.

<Structure of base 10>
Fig. 1(B) is a partial schematic diagram of a cross section in the X-X direction in Fig. 1(A). Fig. 1(B) shows a cross section of the printed matter 1 as seen from the front in the Y direction. As shown in Fig. 1(B), the base 10 has a substrate layer 11, an adhesive layer 12, and a peelable support layer 13 laminated in this order from the side having the information recording medium 30 toward the lower side in the Z direction.
The base layer 11 may be, for example, a resin film, a resin sheet, paper, etc. The material of the base layer 11 may be, for example, inkjet paper, fine paper, craft paper, copying paper, glassine paper, rayon paper, coated paper, synthetic paper, paper laminated with a resin film, NIP fine paper, oriented polypropylene, polyethylene terephthalate, oriented polystyrene, polyvinyl chloride, etc. The base layer 11 may have a flat surface capable of supporting the information recording medium 30.

The adhesive layer 12 is composed of an adhesive for attaching the printed matter 1 to an article when it is used. Any ordinary adhesive that has adhesive properties can be used to form the adhesive layer 12. As for solvent-based adhesives, rubber-based adhesives such as NR, SBR, IR, and CR are mainstream, but emulsion-type acrylic adhesives can also be used. Other types include silicone-based and polyvinyl ether-based adhesives, and any of these can be used, and hot-melt adhesives are also acceptable.

The peelable support layer 13 is a member known as a release paper, release sheet, or the like, which is provided to protect the adhesive layer 12 in the unused state, i.e., before the printed matter 1 is attached to an article, and to prevent the adhesive layer 12 from accidentally sticking to other articles, etc. In FIG. 1(B), the peelable support layer 13 is shown as a single layer, but the peelable support layer 13 may be configured, for example, as a laminate of a base layer and a release layer. The peelable support layer 13 is peeled off and removed when the printed matter 1 is attached to an article. For example, the peelable support layer 13 can be made of the same material as the base layer 11, and the surface on which the adhesive layer is formed can be coated with ink for forming a release layer to impart peelability.

<Structure of Information Recording Medium 30>
The base 10 has an information recording medium 30 on its front surface, i.e., on the upper side in the Z direction. The information recording medium 30 has information used for determining authenticity, such as a code, printed thereon by latent image printing. The image printed on the information recording medium 30 changes when the observation direction of the base 10 is changed.

1B, the information recording medium 30 has a composite image including a glossy layer 31 (first ink layer) and a transparent layer 32 (second ink layer) on the base 10. The composite image is an image formed by a composite layer in which the glossy layer 31 and the transparent layer 32 are superimposed.
The glittering layer 31 is a layer on which a first image including a solid image and a pattern image is printed with ink containing a glittering material.
The transparent layer 32 is a layer on which a second image including an image of a two-dimensional code (code) in a pattern image different from the pattern image of the glossy layer 31 is printed using transparent ink (transparent material).
In this example, the glossy layer 31 and the transparent layer 32 are square-shaped, and the transparent layer 32 is formed over the entire glossy layer 31 .

Here, a method for manufacturing the information recording medium 30 will be briefly described.
First, a base 10 is prepared, and a first image is gravure printed on the base 10 using a glossy ink or the like containing a glittering material to form a glittering layer 31. Various types of ink containing a glittering material for drawing the first image are envisioned, for example, as exemplified below.
For example, the ink may be a silver ink containing aluminum powder, copper powder, zinc powder, tin powder, iron phosphide, etc. Also, the ink may be a mixture of a silver ink and a chromatic ink containing a colored dye such as a pigment or a dye.

Furthermore, the glittering layer 31 may be an ink made of only a glittering material exhibiting a bluish gold or reddish gold color, or may be a mixture of an ink made of a glittering material exhibiting a bluish gold or reddish gold color and a chromatic ink made of the above-mentioned colored pigment.
Furthermore, the ink may be a pearl ink, a liquid crystal ink, an OVI (Optical Variable Ink), a CSI (Color Shifting Ink), or the like, which is an ink containing a functional pigment whose color changes by reflecting light. The pearl ink is an ink containing a pearl pigment that has a pearlescent luster compared to normal pigments and has safety, luster, and a luxurious feel. The liquid crystal ink is an ink containing a liquid crystal that has the property of changing color depending on temperature.
In this example, the glittering layer 31 is made of silver ink containing a glittering material.

Next, a second image is gravure printed on the first image of the glossy layer 31 using a transparent ink or the like to form a transparent layer 32. The ink used to print the second image is, for example, achromatic ink such as matte OP varnish, transparent varnish, ink varnish, transparent ink, or medium ink. Note that these inks may be any printing ink such as ultraviolet curing ink, oxidative polymerization ink, penetrating ink, overheat drying ink, or evaporation drying ink.
The materials used for the above-mentioned shiny layer 31 and transparent layer 32 are merely examples, and other materials may be used as long as they reflect different amounts of light depending on the observation angle.

Here, the thickness of the ink to be applied is, for example, about 1 micrometer in each case. However, the thickness of the ink is not limited to this. Also, for example, the thickness of the ink may be changed depending on the material.
The printing process described above is not limited to gravure printing, but may be wet offset printing, dry offset printing, letterpress printing, waterless lithographic printing, flexographic printing, screen printing, intaglio printing, or the like.

Next, an image printed in the printing process of the information recording medium 30 will be described.
FIG. 2 is a diagram showing an example of an image on the information recording medium 30 according to this embodiment.
3 and 4 are diagrams showing examples of pattern images of the information recording medium 30 according to this embodiment.

2A shows an embodiment in which a second image of a transparent layer 32 is superimposed on a first image of a glossy layer 31. The first image includes an image B1 which is a solid image and an image C1 which is a pattern image. Image B1 forms an outer frame, and image C1 forms micro characters. The second image includes an image C2 which is a pattern image. Image C2 forms an image including a two-dimensional code such as a QR code (registered trademark).
As shown in FIG. 2B, an identification area formed by an image C2, which is the outer frame of a two-dimensional code that is a part of the second image, is formed and overlapped on the image B1.

Next, the printing of images C1 and C2 shown in FIG. 2A will be described with the printing condition that indicates the area that can conceal the background, expressed as a percentage, being referred to as the area ratio, and in particular, the case where the background can be concealed by halftone dots being referred to as the dot area ratio.
3A shows a part of the image C1 of the glossy layer 31 and an enlarged area E1 of the image C1. As shown in the area E1, the image C1 is a pattern image in which a foreground portion C1a and a background portion C1b are expressed in binary.
For example, the foreground portion C1a is printed with a dot area rate of 100%, and the background portion C1b is printed with a dot area rate of 75%. However, this rate is merely an example and is not limited to this. For example, the dot area rate of the foreground portion C1a may be less than 100%, and the dot area rate of the background portion C1b may be other than 75%. In that case, it is desirable that the difference in dot area rate between the foreground portion C1a and the background portion C1b is 15% or more and 50% or less. Furthermore, the density of the foreground portion C1a and the background portion C1b may be reversed.
The image B1, which is a solid image, is printed with a dot area ratio of 100% over the entire image B1.

3B shows a part of the image C2 of the transparent layer 32 and an enlarged view of a region E2 which is a part of the image C2. As shown in the region E2, the image C2 is a pattern image in which a foreground portion C2a and a background portion C2b are expressed in binary.
For example, the foreground portion C2a is printed with a dot area ratio of 100%, and the background portion C2b is printed with a dot area ratio of 25%. However, this ratio is also an example and is not limited to this. For example, the dot area ratio of the foreground portion C2a may be less than 100%, and the dot area ratio of the background portion C2b may be greater than or less than 25% as long as there is a predetermined difference between the foreground portion C2a and the background portion C2b. Furthermore, the density of the foreground portion C2a and the background portion C2b may be reversed.
The difference in density between the foreground portion C2a and the background portion C2b is greater than the difference in density between the foreground portion C1a and the background portion C1b.

Here, the pattern image of the glossy layer 31 and the transparent layer 32 of the information recording medium 30 is not limited to a pattern image consisting of a foreground portion and a background portion.
4A and 4B show a case where the image Cx of the glossy layer 31 and the image Cy of the transparent layer 32 are pattern images consisting of only the foreground portion. In this case, the print areas Cxa and Cya of the images Cx and Cy are printed with a dot area ratio of 100%, and the print areas Cxa and Cya and the non-print areas Cxb and Cyb represent the pattern image in binary.

In the above-mentioned information recording medium 30, the recognizable image changes depending on the angle of the observation viewpoint (observation angle).
FIG. 5 is a diagram for explaining an observation mode based on the structure of the information recording medium 30 according to this embodiment.

FIG. 5A illustrates three positional relationships between an illumination light source L, viewpoints E (Ea to Ec), and an information recording medium 30 in the diffuse reflection region and regular reflection (specular reflection) region.
When the viewpoint E (Ea) is at position P1 with respect to the positions of the illumination light source L and the information recording medium 30 as shown in FIG. 5A, the information recording medium 30 is observed in the diffuse reflection region at position P1. This is the case where the illumination light source L is irradiated from an oblique direction to the surface of the information recording medium 30, and position P1 at this time is the normal direction (Z direction) of the information recording medium 30 and is a position facing the information recording medium 30. Also, when the illumination light source L and the information recording medium 30 are under the same conditions and the viewpoint E (Eb) is at position P2, the information recording medium 30 is observed in the regular reflection region at position P2. In this case, if the angle between the normal line of the information recording medium 30 and the illumination light source L is angle θL, position P2 is a position symmetrical to the illumination light source L with respect to the normal line of the information recording medium 30, and is a position where the information recording medium 30 is viewed from the direction of angle θR, which is the same angle as angle θL.

Here, the illumination light source L outputs visible light.
5B, when the viewpoint E (Ec) is at position P3, the illumination light source L and position P3 are in line-symmetrical positions with respect to the normal line of the information recording medium 30. Therefore, in this case as well, observation is made in the regular reflection region at position P3.
In the following, an example will be described using images C1 and C2 shown in FIG.

When the information recording medium 30 consists only of the glossy layer 31, in the diffuse reflection area, the foreground portion C1a and the background portion C1b of the image C1 in FIG. 3(A) have a large difference in the amount of reflected light due to the difference in density between them, so the foreground portion C1a and the background portion C1b can be distinguished. On the other hand, in the specular reflection area, the foreground portion C1a and the background portion C1b both have a large amount of reflected light, so the difference cannot be sensed and the foreground portion C1a and the background portion C1b cannot be distinguished.

Next, when the information recording medium 30 is composed only of the transparent layer 32, in the diffuse reflection area, the foreground portion C2a and the background portion C2b in Fig. 3B cannot be distinguished because they are transparent. On the other hand, in the specular reflection area, the foreground portion C2a and the background portion C2b can be distinguished because the amount of reflected light varies depending on the difference in density between the foreground portion C2a and the background portion C2b.
When the information recording medium 30 has the transparent layer 32 formed on the glossy layer 31, the foreground portion C1a and the background portion C1b can be distinguished from each other in the diffuse reflection region, but the foreground portion C2a and the background portion C2b cannot be distinguished from each other, so that the foreground portion C1a and the background portion C1b are observed as a whole. In the specular reflection region, the foreground portion C1a and the background portion C1b cannot be distinguished from each other, but the foreground portion C2a and the background portion C2b can be distinguished from each other, so that the foreground portion C2a and the background portion C2b are observed as a whole.

In this way, by using materials (ink, etc.) for the glossy layer 31 and the transparent layer 32 that reflect different amounts of light depending on the observation angle, the image of the glossy layer 31 and the image of the transparent layer 32 can be made to appear in a variety of ways, appearing visible or invisible depending on the observation angle.
Using this principle, the information recording medium 30 is photographed by the reading device 5 to obtain an image of only the transparent layer 32 or only the glossy layer 31, and the information recording medium 30 is used to determine its authenticity.

<Reproduction of printed matter 1>
Next, in order to demonstrate the use of the information recording medium 30 for authenticity determination, a case in which the printed matter 1 is reproduced will be described.
FIG. 6 is a diagram for explaining the positional relationship between the illumination light source L and the camera C when copying the printed matter 1 according to this embodiment.
The information recording medium 30 of the printed matter 1 is illuminated with light from an illumination light source L shown in FIG.

Fig. 6 shows a case where the illumination light source L illuminates the information recording medium 30 from a slightly oblique direction, and the camera C captures an image from a perpendicular direction to the information recording medium 30. When the illumination light source L, camera C, and printed matter 1 are in the positional relationship shown in Fig. 6, as typified by a reproduction machine such as a copy machine, for example, as shown in paragraph [0009] of JP 2009-21812 A, the camera C reads light diffusely reflected by the surface of the printed matter 1. Therefore, depending on the positional relationship between the illumination light source L and the information recording medium 30, the camera C captures images of both the glossy layer 31 and the transparent layer 32 of the information recording medium 30.
In this manner, a copy of the printed matter 1 is produced in the reproduction machine based on the image captured by the camera C.

The copy has a printed body on which the information recording body 30 is printed at a position corresponding to the information recording body 30 (see FIG. 1A) of the printed matter 1. The printed body has a composite image of the pattern image of the glossy layer 31 of the information recording body 30 and the pattern image of the transparent layer 32. The printed body also has a layer of, for example, a black ink containing general carbon, or a colored ink in the case of a color copy. Therefore, no matter what observation angle the printed body is from (diffuse reflection area, regular reflection area, etc.), only the composite image is visible in the printed body. Therefore, the printed body is one in which only the pattern image of the transparent layer 32 cannot be observed, and when an authenticity determination is performed, it can be determined to be a fake.

Next, the reading of the information recording medium 30 by the reading device 5 will be described.
FIG. 7 is a diagram showing the positional relationship between the outer camera 5C and the mobile light 5L of the reading device 5 that reads the information recording medium 30 according to this embodiment.
FIG. 8 is a diagram showing an example of a reading pattern of the information recording medium 30 by the reading device 5 according to this embodiment.
FIG. 9 is a diagram showing a specific example of a reading pattern of the information recording medium 30 by the reading device 5 according to this embodiment.

The reading device 5 shown in Fig. 7 is, for example, a mobile terminal such as a smartphone. In the example described in this embodiment, the information recording medium 30 is read using the reading device 5 at each location (warehouse, during transportation, store, etc.) to check an item to which the printed matter 1 is attached from the time of manufacture to the time of distribution, etc. Therefore, the reading device 5 is not a dedicated device but a mobile terminal carried by a user. The reading device 5 can be used for authenticity determination by installing a processing program 61a described later.
An outer camera 5C (reading unit) and a mobile light 5L (light emitting unit) are provided in close proximity to the rear surface of the housing of the reading device 5. A touch panel display 67 (described later) is provided on the front surface of the housing, which is the side opposite to the side having the outer camera 5C and the mobile light 5L.

Figure 8 (A) shows the layer structure of the information recording medium 30. Figure 1 (B) shows an example of the layer structure of the information recording medium 30, but when the information recording medium 30 in Figure 2 is enlarged to show images C1 and C2, it actually has a layer structure as shown in Figure 8 (A).

When a user operating the reading device 5 obtains an image of the luminous layer 31 of the information recording medium 30, the user photographs the information recording medium 30 using the outer camera 5C without turning on the mobile light 5L. At this time, the outer camera 5C is positioned at viewpoint Ea in the positional relationship between the illumination light source L and the information recording medium 30 in FIG. 5(A). The illumination light source L in this case is the surrounding external light. As a result, as shown in FIG. 8(B), the reading device 5 can obtain an image of the pattern 41 that is only the image C1 of the luminous layer 31.

When obtaining an image of the transparent layer 32 of the information recording medium 30, the user who operates the reading device 5 uses the outer camera 5C to photograph the information recording medium 30 with the mobile light 5L turned on. At this time, the outer camera 5C is located at the viewpoint Ec in the positional relationship between the illumination light source L and the information recording medium 30 in FIG. 5(B). As described above, in theory, an image of the pattern 42 consisting of only the image C2 of the transparent layer 32 can be obtained as shown in FIG. 8(C). However, in reality, the reading device 5 obtains an image including the pattern 42 consisting of only the image C2 of the transparent layer 32, as shown in FIG. 8(D), as well as black noise 44 and white noise 45. Here, the black noise 44 is a portion that would not normally be obtained as a pattern, but appears black due to the influence of the glossy layer 31. Furthermore, the white noise 45 is a portion that would normally be obtained as a pattern, but appears whiter due to the influence of the glossy layer 31 than the portion that has the glossy layer 31 as the base.

A more specific example of an image obtained by photographing the information recording medium 30 with the outer camera 5C while the mobile light 5L of the reading device 5 is turned on will be described below.
FIG. 9A shows an image 48 in which an image showing a finder pattern (mark) made of a transparent layer 32 is superimposed on a high-density pattern image made of a glossy layer 31 .
On the other hand, FIG. 9B shows an image 49 in which a finder pattern image made of the transparent layer 32 is superimposed on a low-density pattern image made of the bright layer 31 .

Image 49 is more susceptible to white noise 45 and black noise 44 than image 48. Therefore, when only considering reading the image of the transparent layer 32, it is preferable to form the image of the transparent layer 32 on the high-density pattern image of the glossy layer 31. However, when the image of the transparent layer 32 is formed on the high-density pattern image of the glossy layer 31, the visual visibility of the image of the transparent layer 32 is improved, and the possibility of recognizing the image of the transparent layer 32 at a glance increases.
Therefore, in this embodiment, the reading device 5 processes the black noise 44 and the white noise 45, thereby converting the image into a pattern 42 including only the image C2 of the transparent layer 32 as shown in FIG. 8C.

<Reading device 5>
Next, the reader 5 for reading the code from the information recording medium 30 of the printed matter 1 will be described.
FIG. 10 is a functional block diagram of the reading device 5 according to the present embodiment.
The reading device 5 includes a control unit 50, a memory unit 60, an outer camera 5C, a mobile light 5L, a touch panel display 67 (display unit), and a communication interface unit 69.

The control unit 50 is a CPU (Central Processing Unit) that controls the entire reading device 5. The control unit 50 appropriately reads and executes an OS (Operating System) and application programs stored in the storage unit 60, thereby cooperating with the above-mentioned hardware and executing various functions.
The control unit 50 includes a light control unit 51, an image receiving unit 52 (reading means), a code area acquisition unit 53 (code area acquisition means), a code identification unit 54 (code identification means), an information acquisition unit 55 (information acquisition means, authenticity determination means), and an information output unit 56 (information output means).

In response to the start of the processing program 61a, the light control unit 51 causes the mobile light 5L to emit light and continues the light output. Note that the light control unit 51 may stop the light output emitted from the mobile light 5L when the image receiving unit 52 described next receives image data of the information recording medium 30.
The image receiving unit 52 faces the outer camera 5C to the information recording medium 30 and receives image data of the information recording medium 30 via the outer camera 5C by having the outer camera 5C read the information recording medium 30.

The code area acquisition unit 53 detects an identification area from the image data, and acquires the code area (read area) based on the detected identification area. Here, the identification area may be the outer frame of the two-dimensional code (see FIG. 2) or a finder pattern (described later) or the like, which can be used to detect the code area.
The code identification unit 54 performs image processing on the code region to identify the code. Here, the code identification unit 54 identifies the code by dividing the code region into cells and performing binarization processing using the luminance value of each cell. The binarization processing is a process of changing the luminance value of a cell by using the average value of the luminance value of the cell and the luminance values of the cells located in the vicinity of the cell. Then, the binarization converts the changed luminance value of each cell to black or white using a threshold value.

The information acquiring unit 55 performs a predetermined conversion on the code identified by the code identifying unit 54, and acquires variable information.
The information output unit 56 outputs information based on the variable information acquired by the information acquisition unit 55 to the touch panel display 67 .

The storage unit 60 is a storage area such as a semiconductor memory element for storing programs, data, etc. required for the control unit 50 to execute various processes.
It should be noted that a computer refers to an information processing device equipped with a control unit, a storage device, etc., and the reading device 5 is an information processing device equipped with a control unit 50, a storage unit 60, etc., and is included in the concept of a computer.

The storage unit 60 stores a program storage unit 61 .
The program storage unit 61 is a storage area for storing various programs. The program storage unit 61 stores a processing program 61a (program). The processing program 61a is a program for executing each function of the control unit 50.

The touch panel display 67 functions as a display unit constituted by a liquid crystal panel or the like, and also functions as an input unit that detects touch input by the user's finger or the like.
The communication interface unit 69 is an interface for communicating with an external server or the like.

<Processing of the reading device 5>
Next, the process of the reading device 5 will be described.
FIG. 11 is a flowchart showing the reading process in the reading device 5 according to the present embodiment.
FIG. 12 is a flowchart showing the code identification process in the reading device 5 according to this embodiment.
FIG. 13 is a diagram for explaining the code identification process in the reading device 5 according to the present embodiment.
14 and 15 are diagrams for explaining the binarization process in the reading device 5 according to this embodiment.

First, when a user operates the reading device 5 to start the processing program 61a, the control unit 50 of the reading device 5 starts the reading process shown in FIG.
In step S11 of FIG. 11 (hereinafter, "step S" will be simply referred to as "S"), the control unit 50 of the reading device 5 activates the outer camera 5C.
In S12, the control unit 50 (light control unit 51) causes the mobile light 5L to emit light.

In this reading process, since the user wishes to determine the authenticity of the information recording medium 30, the user identifies a specular reflection area where only the second image of the transparent layer 32 used to determine the authenticity of the information recording medium 30 is visible, and performs an operation to read the image. To identify the specular reflection area, for example, the user may position the reading device 5 so that it faces the information recording medium 30 in the normal direction of the information recording medium 30. In this way, the positional relationship between the mobile light 5L and the outer camera 5C of the reading device 5 becomes similar to the relationship between the illumination light source L and position P3 in FIG. 5(B), and the outer camera 5C can read the second image of the transparent layer 32 of the information recording medium 30.

In S13, the control unit 50 judges whether or not a shooting operation has been received. The control unit 50 displays, for example, a shutter button (not shown) on the touch panel display 67. Then, when the control unit 50 receives the selection of the shutter button by the user, it judges that a shooting operation has been received. If a shooting operation has been received (S13: YES), the control unit 50 moves the process to S14. On the other hand, if a shooting operation has not been received (S13: NO), the control unit 50 remains in this process until a shooting operation is received.
In S14, the control unit 50 (image receiving unit 52) receives image data captured via the outer camera 5C.
In the process of S13 and S14, the photographing is performed by the photographing operation. However, the photographing may be performed automatically by the control unit 50.
In S15, the control unit 50 performs a chord identification process to identify a chord from the image data.

Here, the chord identification process will be described with reference to FIG.
In S21 of FIG. 12, the control unit 50 (code area acquisition unit 53) detects an identification area included in the image data.
Fig. 13A shows a captured image 70 on which lines for dividing each cell have been drawn, and Fig. 13B shows an image 71 in which an identification region 71a has been detected.

In S22 of FIG. 12, the control unit 50 (code area acquisition unit 53) acquires a code area based on the detected identification area.
Fig. 13C shows an image 72 in which only the code region is included based on the identification region 71a detected from the image 71 in Fig. 13B. The control unit 50 can obtain the image 72 containing only the code region by deleting the identification region 71a and the inner width of the identification region 71a.

In S23 of FIG. 12, the control unit 50 (code identification unit 54) divides the code area into cells.
FIG. 13D shows an image 73 obtained by dividing the image 72 in FIG. 13C into cells.
In S24 of FIG. 12, the control unit 50 (code identification unit 54) performs binarization processing for each cell using the luminance value of each cell.
FIG. 13(E) shows an image 74 obtained by averaging the brightness values of each cell of image 73 in FIG. 13(D), and FIG. 13(F) shows an image 75 after binarization processing in which each cell is made black or white.

Here, the binarization process will be described with reference to FIGS.
In Fig. 14, the control unit 50 classifies each cell in the image 73 shown in Fig. 13(D). Next, the control unit 50 obtains the average value for each classification, and sets the obtained average value as the brightness value of each cell belonging to the classification. For example, for a small image 81 including a cell 81a and its surrounding cells, a small image 91 that absorbs the noise (black noise and white noise) of each cell can be obtained. The control unit 50 performs this process on each cell included in the image 73 (Fig. 13(D)) as the processing target, thereby obtaining the image 74 in Fig. 13(E).

In the image of the code region, the bright and dark regions change like a gradation depending on the position of the mobile light 5L. In addition, the mobile light 5L is a low light source, and the brightness of the light source gradually decreases as the light is continuously irradiated, so the difference between the bright and dark regions gradually occurs. Therefore, if the same threshold is used for the entire image when binarizing, there is a problem that the noise parts cannot be correctly determined. Therefore, as a binarization process, a process is performed for each cell to set a threshold value based on the average of the surrounding brightness values on a cell-by-cell basis and perform a judgment.
An example of the process is shown in Fig. 15. The image 74 includes a small image 91 included in a bright region Ra and a small image 92 included in a dark region Rb. Here, Fig. 15 shows the luminance values of each cell in the small image 91 and the small image 92.

Here, the process of converting to binary will be described using small image 91 as an example. The average brightness value of all cells included in small image 91 is 144. The brightness value of cell 91a, which is the target cell, is 125. Since the brightness value (125) of cell 91a is lower than the average brightness value (144), control unit 50 determines that cell 91a is a black cell.
Next, in the small image 92, the average luminance value of all cells contained in the small image 92 is 78. Furthermore, the luminance value of the target cell, cell 92a, is 90. Since the luminance value (90) of cell 92a is higher than the average luminance value (78), the control unit 50 determines that cell 92a is a white cell.
In the above example, since cell 91a and cell 92a are not located on the periphery of image 74, there are eight surrounding cells, and the average brightness value is the average value of nine cells, including the cell itself and the eight surrounding cells. If the cells are located on the periphery of image 74, there may be five or three surrounding cells.

In this way, by performing a process for each cell in which a threshold is set based on the average surrounding brightness values and a judgment is made, even if image 74 has bright areas Ra and dark areas Rb, binarization can be performed using the average brightness value of the surrounding cells, making it possible to make a correct judgment.

After the control unit 50 performs the code identification process, in S16 of FIG. 11, the control unit 50 (information acquisition unit 55) performs a predetermined conversion process on the code identified by the process of S15 to acquire variable information. Here, if the code is correctly identified by the process of S15, the variable information can be obtained by the predetermined conversion process. On the other hand, if the code cannot be correctly identified by the process of S15, or if an image of an illegally printed matter such as a copy is read and processed, the variable information cannot be obtained by the predetermined conversion process.

In S17, the control unit 50 (information acquisition unit 55) determines whether or not the variable information has been acquired. If the variable information has been acquired (S17: YES), the control unit 50 moves the process to S18. On the other hand, if the variable information has not been acquired (S17: NO), the control unit 50 moves the process to S19.

In S18, the control unit 50 (information output unit 56) outputs information based on the variable information to the touch panel display 67. Here, the information based on the variable information may be, for example, a serial number unique to the information recording medium 30, or a message such as "This is a genuine product." Thereafter, the control unit 50 ends this process.
On the other hand, in S19, the control unit 50 outputs a message indicating a read error to the touch panel display 67. Note that the message to be output may not be a message indicating a read error, but rather a message indicating that the item is a fake. Thereafter, the control unit 50 ends this process.

As described above, according to this embodiment, the following effects are obtained.
(1) The information recording medium 30 includes a solid image B1 in the glossy layer 31, and the outer frame of the two-dimensional code in the transparent layer 32 is arranged to overlap the image B1, so that the code area can be read reliably.
(2) The image on the glossy layer 31 is made into micro characters and a two-dimensional code is formed on the micro characters, so that the two-dimensional code can be made difficult to recognize visually.
Furthermore, by forming the two-dimensional code on the transparent layer 32 using a pattern image, it is possible to make the two-dimensional code more difficult to recognize visually.

(3) The information recording medium 30 displays the second image as a two-dimensional code and the outer frame of the code, and by recognizing the outer frame, the code area of the two-dimensional code can be grasped. As a result, the code area can be read reliably.

(4) In the information recording medium 30, the glossy layer 31 is made of a glossy material, so that the transparent layer 32 can be made more visible depending on the observation angle.
(5) The printed matter 1 having the information recording medium 30 can be attached to a variety of articles, so that the information recording medium 30 can be used for brand protection purposes by code reading.

(6) The reading device 5 outputs light to read the information recording medium 30 at an observation angle where only the transparent layer 32 is visible, detects an identification area from the read image, acquires a code area based on the detected identification area, and performs image processing on the acquired code area to identify the code. Therefore, the code area can be acquired reliably from the identification area. Furthermore, the code can be identified by image processing.

(7) The reading device 5 divides the code area into cells and performs binarization processing using the brightness value of each cell to identify the code. By performing binarization processing on a cell-by-cell basis, the code can be easily identified.
In addition, the binarization process changes the luminance value of a cell using the average value of the luminance values of the cells in the same classification, so that the luminance values of the cells in the same classification as the cell being processed can be averaged.
Furthermore, since the binarization process binarizes the target cell using the average brightness value of the surrounding cells, appropriate binarization can be achieved even when the irradiated light has a gradational effect.

(8) The reading device 5 acquires variable information from the identified code and outputs information based on the acquired variable information to the touch panel display 67. Therefore, for example, the authenticity determination result can be output to the touch panel display 67.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments. Furthermore, the effects described in the embodiments are merely a list of the most favorable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments. Note that the above-mentioned embodiments and the modified forms described below can be used in appropriate combinations, but detailed explanations will be omitted.

(Modifications)
(1) In the present embodiment, the identification region is described as an outer circumferential frame, but is not limited to this. For example, the identification region may be a mark indicating the presence of a code, and in the case of a two-dimensional code, the mark may be a finder pattern.
FIG. 16 is a diagram showing an example of an image of an information recording medium according to a modified embodiment.
FIG. 17 is a diagram for explaining the binarization process in the reading device according to the modified embodiment.
Fig. 16(A) shows an information recording medium 30-2 in Fig. 16(B) formed by superimposing an image C1 and an image B1 of the glossy layer 31-2 and an image C2 of the transparent layer 32-2. Here, the finder pattern of the transparent layer 32 is formed on the image B1.
In this information recording medium 30-2, when the reader 5 reads the transparent layer 32-2 of the information recording medium 30-2, the finder pattern can be read reliably, so that the code area can be easily specified.

Also, as shown in FIG. 17, if the finder pattern is stored in advance in the storage unit 60 during binarization processing by the reading device 5, the finder pattern portion of image 174 can be fixed and binarized as in image 174-2. This can make the code identification process even easier.

(2) In the present embodiment, the pattern image is printed, but the present invention is not limited to this. The pattern image may be formed by a method other than printing, such as transfer printing or laser drawing.
(3) In this embodiment, a label has been described as an example of a printed matter having an information recording medium, but this is not limiting. For example, a medium having an information recording medium may be a ticket used to enter an entertainment facility or a card used in a game. The information recording medium may also be used for digital watermarking. Furthermore, the information recording medium is not limited to a medium having an information recording medium, and may be a booklet having an information recording medium.
(4) In the present embodiment, the glossy layer 31 and the transparent layer 32 are described as being square-shaped, but are not limited thereto. For example, the glossy layer 31 may be other shapes such as rectangular, circular, or elliptical. In addition, the transparent layer 32 may be rectangular or the like depending on the shape of the code, for example, in the case of a barcode.

(5) In this embodiment, the transparent layer 32 is formed directly on the glossy layer 31, but the present invention is not limited to this. For example, a substrate such as a transparent film may be provided between the glossy layer 31 and the transparent layer 32. Also, for example, in addition to the transparent layer 32 formed on the glossy layer 31 described in this embodiment, a substrate such as a transparent film may be provided on the transparent layer 32. By having a substrate such as a transparent film in this way, the glossy layer 31, which is the layer below the transparent film, is less likely to be scraped off.

(6) In the present embodiment, the image of the glossy layer 31 is described as an example in which micro characters as shown in Fig. 2 are formed using a pattern image as shown in Fig. 3, but the image is not limited to this. For example, the image may be only a pattern image as shown in Fig. 3. In this way, the image of the glossy layer 31 can be made meaningless to a person at first glance by using the pattern image.
(7) In the present embodiment, the process by the reading device is to read the image C2 of the transparent layer 32 and identify the code to, for example, determine the authenticity, but is not limited to this. For example, if the glossy layer 31 also contains a code and the code of the glossy layer 31 can also be read, the authenticity determination may determine that the item is genuine. Furthermore, the authenticity may be determined based on whether or not a combination of the code of the glossy layer 31 and the code of the transparent layer 32 is stored in an authenticity determination table (not shown) stored in the memory unit of the reading device.

(8) In this embodiment, the transparent layer forms a code using a pattern image, but this is not limited to the above. The transparent layer may form a code using a solid image.

REFERENCE SIGNS LIST 1 Printed matter 5 Reading device 5C Out camera 5L Mobile light 10 Base 11 Substrate layer 12 Adhesive layer 13 Peelable support layer 30, 30-2 Information recording body 31, 31-2 Luminous layer 32, 32-2 Transparent layer 41, 42 Pattern 44 Black noise 45 White noise 50 Control unit 51 Light control unit 52 Image reception unit 53 Code area acquisition unit 54 Code identification unit 55 Information acquisition unit 56 Information output unit 60 Memory unit 61a Processing program 67 Touch panel display B1, C1, C2 Image C Camera L Illumination light source

Claims (16)

An information recording medium having a first ink layer and a second ink layer,
The first ink layer and the second ink layer are
provided on one surface of the substrate,
Each is designed to reflect different amounts of light depending on the viewing angle.
the first ink layer is a first image including a solid image,
the second ink layer is a second image formed of a transparent material and including a code having variable information;
An information recording medium, wherein an identification area for identifying a reading area of the code in the second image is formed superimposed on the solid image. 2. The information recording medium according to claim 1,
The first image further includes a pattern image;
An information recording medium, in which at least a part of the second image is formed so as to be superimposed on the pattern image. 3. The information recording medium according to claim 1,
The second image includes a pattern image. In the information recording medium according to any one of claims 1 to 3,
The code is a two-dimensional code,
An information recording medium, wherein the identification area of the code is an outer frame of the code. In the information recording medium according to any one of claims 1 to 3,
The code is a two-dimensional code,
An information recording medium, wherein the identification area of the code is a mark indicating the presence of the code. In the information recording medium according to any one of claims 1 to 5,
An information recording medium, wherein the first image includes an image of a code different from the second image. In the information recording medium according to any one of claims 1 to 6,
The information recording medium, wherein the first ink layer is formed of a glittering material. A label comprising an information recording medium according to any one of claims 1 to 7. A reading device for reading the information recording medium according to any one of claims 1 to 7,
A reading unit;
a light emitting unit that is provided near the reading unit and that irradiates light;
a reading unit for reading an image including the second image of the information recording medium by the reading unit while the light is being irradiated by the light emitting unit;
a code region acquisition means for detecting the identification region from the image read by the reading means and acquiring a code region based on the detected identification region;
a code identification means for performing image processing on the code region acquired by the code region acquisition means to identify the code;
A reading device comprising: 10. The reading device according to claim 9,
The code identification means divides the code area into cells, and identifies the code by performing binarization processing using the luminance value of each cell. 11. The reading device according to claim 10,
The binarization process obtains an average value for each classification based on the brightness value of each cell, and sets the obtained average value as the brightness value of each cell belonging to the classification. A reading device according to claim 10 or 11,
A reading device, wherein the binarization process binarizes the one cell using an average value of a luminance value of the one cell and luminance values of each cell located in the vicinity of the one cell. A reading device according to any one of claims 9 to 12,
The code identification means is a reading device that, when the detected identification area has a pre-stored shape, performs a binarization process corresponding to the shape. A reading device according to any one of claims 9 to 13,
an information acquiring means for acquiring the variable information from the code identified by the code identifying means;
an information output means for outputting information based on the variable information acquired by the information acquisition means to a display unit;
A reading device comprising: A program executed by a computer for determining the authenticity of an information recording medium according to any one of claims 1 to 7,
The computer,
a reading means for reading an image including the second image of the information recording medium;
a code region acquisition means for detecting the identification region from the read image and acquiring a code region based on the detected identification region;
a code identification means for performing image processing on the acquired code area to identify the code;
an information acquisition means for acquiring the variable information from the identified code;
an authenticity determining means for determining that the information recording medium is genuine when the variable information can be obtained;
A program to make it function as such. A method for determining authenticity of an information recording medium according to any one of claims 1 to 7, comprising the steps of:
The computer
reading an image including the second image of the information recording medium;
detecting the identification area from the read image and acquiring a code area based on the detected identification area;
performing image processing on the acquired code region to identify the code;
acquiring the variable information from the identified code;
a step of determining that the information recording medium is genuine when the variable information is obtained;
A method for determining authenticity comprising:

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