JP4649658B2 - Hidden image or hidden information authentication method and authentication system - Google Patents

Description

  The present invention collates an image appearing in a predetermined wavelength region with an authentic image against an image or information concealed printed matter, reads concealment information from the manifested image, and collates the content with authentic information. The present invention relates to a method for authenticating a concealed image or concealment information for authentication and an authentication system thereof.

  Precious printed matter such as banknotes, securities and passports, and certificates that authenticate individuals such as driver's licenses, passports, insurance cards, etc., always incorporate new anti-counterfeiting technology so that they are not counterfeited or tampered with by a third party. Is required.

  One example of such anti-counterfeiting technology is “half-tone printed matter” filed by the authorities. As shown in FIG. 19, a plurality of sets of one first region (14) and one second region (15, 16) adjacent to the first region are arranged. Is surrounded by a plurality of first regions, the first region has a larger area than the second region, and the second region (15, 16) is a black ink containing an infrared absorbing dye. A second region (15) constituted by using a black color, and a second region (16) of black type constituted by using an ink not containing an infrared absorbing dye. A gradation image is configured by the 2a region of the plurality of second regions according to the ratio of the 2a region to the 2b region.

  For example, if the embedded image (IR image) of the second area is a pattern or mark, the area is imaged with a camera (IR camera) having sensitivity in the IR area, and the embedded pattern is displayed through the display monitor. It can be confirmed with the naked eye, and as a result, authenticity determination can be performed according to the judgment of the observer.

  In this way, when the embedded information is a pattern or a mark, and the authenticity of the printed matter is determined by the observer's judgment, the human eye is relatively flexible, so even if the contrast of the IR region is low, It was possible to recognize the pattern.

  However, when the above-described captured IR image is subjected to machine authentication for a genuine image by a technique such as pattern matching, the IR reflection area and the absorption area may be sufficient depending on the physical state of the printed matter and the image capturing environment. As a result, there is a case where it is not determined to be authentic even if it is a genuine printed matter due to the reason that the density difference cannot be obtained and the density contrast of the IR image is low.

  In addition, when a printed material is produced using the embedded image (IR image) of the second region as code information and machine reading is to be performed on the printed material, a general method, that is, an image captured by an IR camera is used. Only the process of directly authenticating the information does not lead to the acquisition and authentication of the concealed information. This is because the density of the captured IR image is low, the contrast necessary for performing mechanical authentication processing cannot be obtained, and normal authentication processing cannot be performed.

  Therefore, it is conceivable to increase the contrast of the IR image so that the information hidden by the authentication process can be acquired. However, if the ratio of the second region is increased (the contrast of the IR image is increased), Since the pattern appears on the visible image, not only does it adversely affect the visible image but also the confidentiality is lowered, and the effect as embedded information is lost. Therefore, there is a limitation that the contrast of the IR image cannot be increased.

  In order to solve this, it is necessary to acquire a concealed image or concealment information by the process shown in FIG. In this process, first, code information is captured as an image by an IR irradiation and an IR camera into an authentication device such as a personal computer. Next, the captured image is subjected to image processing such as density correction processing and binarization using image processing software, and the predetermined authentication processing program is executed on the image processed image so that the code information is concealed. It is necessary to obtain the information that is stored, and it is necessary to prepare multiple machines and software, and to perform the reading process in three stages. Treatment).

  Further, when an image capturing device of an image capturing device having an extremely large number of pixels and a high resolution is used, the halftone dot structure of the printed matter is clearly imaged. When the QR code in FIG. 12A is captured by a high-resolution image capture device having a large number of pixels, in the QR code cell, as shown in FIG. Since it is a value and does not transmit light, it is recognized as a dark color. Other than the halftone dot portion in the cell, it is recognized as a light color because it is a high pixel value and transmits light. In this way, the QR code cell portion cannot be recognized as a solid region because of the large number of pixels and high resolution, and a region other than a halftone dot region having a low pixel value and a halftone dot having a high pixel value. It is clearly recognized as a collection of areas, and as a result, there is a possibility of affecting the authentication process.

  Furthermore, the coded IR concealed image is given as an example of the concealed image, but the same can be said for the concealed image in the visible region including the UV concealed image such as fluorescent light emission and the transmitted light image such as watermark. In some cases, it is difficult to authenticate the image or information.

  The recognition work may be performed in various environments, and may naturally be affected by outside light such as an indoor fluorescent lamp when an IR image is captured. In addition, it is conceivable that there is an influence of characteristics between devices due to a time difference from the capture timing when capturing an image from the IR camera. As a result of these influences, the image quality of the captured image is reduced in the form of flickering and white noise on the image.

  Also, spatial density difference due to density unevenness that occurs in the captured image due to unevenness of irradiation light including external light and spatial non-uniformity of the density of the imaging area due to the influence of dark current etc. in the IR camera. Also, the decoding process was hindered.

  An object of the present invention is to solve the above-described problem. Specifically, a concealed image having characteristics with respect to reflection, transmission and / or absorption in a predetermined wavelength region is imaged n times by an imaging unit, and imaging is performed. It is an object of the present invention to provide a concealed image or concealment information authentication method for authenticating the authenticity of an acquired image, and an authentication system thereof.

  The method for authenticating a concealed image according to the present invention is a method for authenticating a concealed image in a printed material on which a concealed image has been applied with an ink composition having characteristics of reflection, transmission and / or absorption in a predetermined wavelength region. Then, the hidden image information is acquired by imaging n times by the imaging unit, the acquired n pieces of hidden image information are added, predetermined gradation conversion is performed on the image obtained by the addition, and gradation conversion is performed. The concealed image is authenticated by collating the subsequent image with a genuine image stored in advance.

  The addition of concealment image information performed by the concealment image authentication method of the present invention is an S / N ratio improvement process, and the predetermined gradation conversion is an absorption part in a predetermined wavelength region and a reflection part in a predetermined wavelength region. It is characterized by contrast amplification processing for increasing the density difference.

  The addition of concealment image information performed by the concealment image authentication method of the present invention is an S / N ratio improvement process, and the predetermined gradation conversion is an absorption part in a predetermined wavelength region and a reflection part in a predetermined wavelength region. And a contrast amplification process for increasing the density difference between the pixel values and an averaging process for averaging the low pixel value and the high pixel value.

  The concealment information authentication method of the present invention is a concealment image authentication method in a printed matter in which a concealment image is applied with an ink composition having characteristics of reflection, transmission and / or absorption in a predetermined wavelength region, Then, the hidden image information is acquired by imaging n times by the imaging unit, the acquired n pieces of hidden image information are added, predetermined gradation conversion is performed on the image obtained by the addition, and gradation conversion is performed. The concealment information is acquired by decoding the subsequent image, and the concealment information is authenticated by comparing the acquired concealment information with the authentic information stored in advance.

  The addition of the concealment image information performed by the concealment information authentication method of the present invention is an S / N ratio improvement process, and the predetermined gradation conversion is an absorption part in a predetermined wavelength region and a reflection part in a predetermined wavelength region. Contrast amplification processing to increase the density difference of light and density unevenness removal processing to remove unevenness in illumination due to spatial nonuniformity of illumination conditions due to ambient light and unevenness in the imaging area due to dark current etc. It is characterized by being.

  The addition of the concealment image information performed by the concealment information authentication method of the present invention is an S / N improvement process, and the predetermined gradation conversion is an absorption point in a predetermined wavelength region and a reflection point in a predetermined wavelength region. Contrast amplification processing to increase the density difference, illumination unevenness due to spatial nonuniformity of illumination conditions due to ambient light, density unevenness removal processing to remove density unevenness due to nonuniformity in the imaging area due to dark current, etc., and It is an averaging process for averaging a low pixel value and a high pixel value.

  The authentication system of the present invention is an authentication system for authenticating a concealed image or concealment information, and captures a concealed image printed with an ink composition having characteristics of reflection, transmission and / or absorption in a predetermined wavelength region. Image capturing device for capturing n times and acquiring n pieces of concealed image information, and adding n pieces of acquired concealed image information and performing predetermined gradation conversion on the obtained image The image after the gradation conversion and the genuine image stored in advance are collated and authenticated, or the concealment information is obtained by decoding the image after the gradation conversion, and the acquired concealment information and It is comprised with the server for collating and authenticating the authentic information memorize | stored beforehand, The image capture device and the server are connected via the network.

  The image capturing device of the authentication system of the present invention is composed of an illumination-integrated imaging unit, an antireflection sheet, and a support, and a total antireflection sheet is foldably fixed to the lower portion of the support, One end of a support bar is swingably attached to the upper part of the support, and an illumination-integrated imaging unit is fixedly attached to the other end of the support bar.

  By this method, when authenticating an image in a predetermined wavelength region, for example, authentication by reading a two-dimensional code, pattern matching with a genuine image, etc. Even when a sufficient density difference cannot be obtained between the reflection region and the absorption region, it is effective because an image with a high S / N ratio and a high contrast can be easily obtained.

  Also, with this authentication system, authentication can be performed at a remote location via a network, authenticity determination information including the authentication result can be centrally managed at the server, and information can be shared via the server.

  Furthermore, even when changing the authentication method or registering a new authentication method, it is only necessary to send the update contents from the server, and no update work is required for each terminal, which contributes to a significant reduction in time, cost and work. .

  In addition, since this device can execute all the processes required for authentication by pressing a predetermined button once, no special skill is required on the operation side, and anyone can easily perform the authentication process. . Furthermore, the image capturing apparatus can perform image capturing and authentication without limiting the use environment by the illumination unit and various density correction processes included in the image capturing apparatus.

  In addition to the IR concealment image mentioned as an embodiment of the present invention, the predetermined wavelength region does not have a sufficient density difference in the visible light region, such as a fluorescent light emission image having a low light emission intensity or an unclear watermark image. The present invention is also optimal when performing a mechanical authentication process that requires reading concealment information using a low-contrast, unclear image with many noise components. The same is true for images in the ultraviolet region.

  In addition, since this method can achieve a high S / N ratio and a high contrast, it is highly convenient and effective as an auxiliary tool for human visual authentication.

  With the auxiliary illumination and various density correction processes provided in the apparatus, IR images can be captured regardless of day or night, and the use environment is not limited. In addition, since the power source of this apparatus is battery-powered, it can be used in places such as outdoors where supply by an AC adapter cannot be obtained.

  By registering the authenticity determination processing method (algorithm) used for the determination only in the server, it is possible to prevent the authentication method from spreading and improve confidentiality.

  Since the certificate authority performs authenticity determination, even if the authentication method is changed or a new authentication method is registered, it only needs to be set on the server, and no update work is required for each terminal. Can be reduced.

  Since the authentication function can be omitted in the authentication terminal, machine power is not required, and it can be made small and inexpensive.

  Since no database is required, the capacity of the server is small and there is no need for database registration, so there is no limit on the number of authentications. In addition, there is no risk of leakage of personal information by unauthorized persons.

  Since the embedding of the authentication data is realized by printing the authentication pattern, a special element such as an IC is not necessary.

  Moreover, since it can be comprised with a single material, manufacture is easy and it can manufacture at low cost. When the medium is paper, the printed matter that is no longer needed can be incinerated, so that it does not become non-burnable waste. Therefore, environmental considerations can be taken, and information leakage can be prevented by physical erasure.

  When the Internet is used as a communication means, there are no time and place restrictions, and many people can easily authenticate. As a result, it is not necessary to newly lay a dedicated line, so that the laying cost, time, etc. are unnecessary, and the authentication conditions can be easily prepared.

  Even if the object to be authenticated is a printed matter by a plastic card or a color laser printer, an image can be taken without being affected by reflected light.

  Since the imaging unit and the illumination are integrated, and the structure is simple, the size and weight can be reduced, and the manufacturing cost and the repair cost can be reduced.

  Since the printed matter to be imaged is set in contact with the antireflection sheet, the totally reflected light is reflected as diffused and smoothed light without directly entering the imaging unit, enabling imaging with less noise It becomes.

  An embodiment of an integrated authentication system according to the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of an integrated authentication system according to the present invention. FIG. 2 shows the configuration of the integrated authentication system according to the present invention.

  First, an integrated authentication system according to the present invention will be described with reference to FIGS. The integrated authentication system includes an image capture device (1) and an authentication terminal (2).

  FIG. 3 shows the image capturing device (1), where (a) is a view from above, (b) is a view from below, and (c) is a view showing a form during storage. As shown in FIG. 3, the image capturing device (1) includes an imaging unit (3), an illumination unit (4), a total reflection preventing sheet (17), and a support (18), and the illumination unit (4). ) Is arranged around the image pickup unit (3) and is configured to be an illumination-integrated image pickup unit.

  A total reflection preventing sheet (17) is foldably fixed to the lower part of the support (18), and one end of a support bar is swingably attached to the upper part of the support (18). The illumination-integrated imaging unit (3, 4) is fixed to the other end of the support bar.

  The illumination unit (4) is means for irradiating the printed material with light, and includes any one of IR illumination, visible light illumination including transmitted light, and UV illumination. Usually, when capturing a concealment image, it is possible to capture in a natural state such as sunlight. However, when the desired image cannot be captured due to weak light at night or indoors, appropriate illumination can be selected from IR illumination, visible light illumination, and UV illumination so that irradiation corresponding to the concealed image is possible. Yes. In addition, although the case where the illumination part for total reflection light is used is shown in the figure of this invention, when authenticating with transmitted light images, such as a penetration image, the illumination part for transmitted light is used.

  The total reflection preventing sheet (17) is a means for preventing total reflection light from entering the imaging unit (3), and is preferably a satin processed film that passes a specific wavelength.

This film is preferably resinous in consideration of adhesion to printed matter, weight, and handleability, and at least the image capturing device (1) side needs to be textured. If it is too rough, a satin pattern appears on the captured image, and authentication accuracy may be reduced.

  In addition, if the film is too thick, the amount of transmitted light is attenuated and the diffusion of light is increased, and the quality of the captured image may be reduced. On the other hand, if it is too thin, strength and durability are lowered.

  Therefore, in view of the above-mentioned necessary conditions, a suitable film as the total antireflection sheet (17) is, for example, a Z mat film manufactured by 100,000,000, and it is desirable to use a film having a thickness of about 125 μm. . However, the present invention is not limited to this as long as an image suitable for authentication processing can be captured.

  The imaging unit (3) is means for capturing a hidden image having characteristics with respect to reflection, transmission, and / or absorption in a predetermined wavelength region n times, and acquiring n pieces of hidden image information by imaging.

  At this time, when imaging twice or more, imaging is performed with the relative positional relationship between the imaging unit (3) and the printed matter kept constant so that the imaging location of the printed matter does not fluctuate in each image. In this case, as an installation means of the imaging unit (3), a fixture such as a tripod or a stand may be used.

  The authentication terminal (2) is comprised from the control part (5), the memory | storage part (6), and the alerting | reporting part (7).

  The control unit (5) adds n pieces of concealed image information captured by the image capturing device (1), performs a predetermined gradation conversion on the image obtained by the addition, and after the gradation conversion Authentication of the concealed image by comparing the image of the image and the genuine image stored in advance, or the n pieces of concealed image information captured by the image capturing device (1) are added and added. The obtained image is subjected to predetermined gradation conversion, and the concealment information is acquired by decoding the image after the gradation conversion, and the acquired concealment information and the storage unit (6) are stored in advance. This is means for authenticating the concealed image by collating the authentic image and notifying the notifying unit (7) of the authentication result.

  The storage unit (6) is means for previously storing the authentic image of the concealed image to be authenticated or the authentic information of the concealing information to be authenticated, and further storing the captured image and the authentication result.

  An alerting | reporting part (7) is a means to alert | report the authentication result by the authentication process in a control part (5). As a means for notifying the authentication result of the authentication to the authenticator, any means such as a screen display on a personal computer or the like, a print output to a printer or the like, or a sound is not selected.

  Next, an embodiment of a remote authentication system using a network line in the present invention will be described with reference to the drawings.

  FIG. 4 shows a form of a remote authentication system using a LAN according to the present invention. FIG. 5 shows a form of a remote authentication system using the Internet in the present invention. FIG. 6 shows the configuration of a remote authentication system according to the present invention.

  First, the configuration of the remote authentication system according to the present invention will be described with reference to FIG. In the remote authentication system, an image capturing device (1) and a server (8) are connected via a network (9).

  The image capturing device (1) is means for capturing an authentication image, and includes an imaging unit (3), a notification unit (7), a data transmission / reception unit (12), an operation unit (10), and a control unit (5). It is composed of

  The image capturing device (1) is a sensor, a camera, or the like that captures a signal (image data or the like) necessary for authentication.

  An alerting | reporting part (7) is a means to alert | report the result of authentication.

  The data transmission / reception unit (12) is means for transmitting captured data and the like to the server (8) and receiving an authentication result from the server (8).

  The operation unit (10) is means for performing operations such as image capture and data transmission / reception.

  The control unit (5) is means for controlling each part constituting the image capturing device (1).

  The server (8) is a part that authenticates the captured image, and includes a storage unit (6), an operation setting unit (11), a data transmission / reception unit (13), and a control unit (12).

  The storage unit (6) is means for storing a series of authentication algorithms and temporarily storing data transmitted from the image capturing device (1) and authentication results transmitted to the image capturing device (1).

  The operation setting unit (11) is means for selecting an authentication technique, operating the apparatus, and registering or changing a new algorithm.

  The data transmission / reception unit (13) is means for receiving captured data or the like from the image capturing device (1) and transmitting an authentication result to the image capturing device (1).

  The control unit (12) is a means for controlling each part constituting the server (8), and in accordance with the authentication algorithm for the captured data transmitted from the image capturing device (1). A means for performing a series of authentication processes. The authentication process here is a predetermined method set in advance, and is a decoding process corresponding to the encoding method used when creating the printed matter.

  Next, an authentication method will be described with reference to the drawings. FIG. 7 shows a flow of a hidden image authentication method according to an embodiment of the present invention. FIG. 8 shows a processing procedure in the S / N ratio improvement processing. FIG. 9A shows the image density distribution before the contrast amplification process, and FIG. 9B shows the image density distribution after the contrast amplification process. FIG. 10 shows the density correction function. FIG. 11 shows a flow of a concealment information authentication method according to an embodiment of the present invention. FIG. 12A shows image information when the concealed image of the printed material in one embodiment of the present invention is captured in the imaging unit, and FIG. 12B shows the pixel value of the XY portion of the image information. FIG. 12C shows pixel values obtained by averaging the pixel values of FIG.

  An authentication method using a hidden image will be described according to the flow shown in FIG. First, a concealed image having characteristics with respect to reflection or absorption in a predetermined wavelength region is imaged n times by the imaging unit (3) (STEP01).

  When imaging twice or more, it is possible to prevent fluctuations in the imaging area by fixing the imaging unit with a fixing device such as a tripod or a stand.

  Usually, when capturing a concealment image, it is possible to capture in a natural state such as sunlight. However, if the light is weak at night or indoors, there is a possibility that desired imaging cannot be performed. In such a case, it is possible to irradiate with desired illumination light corresponding to the concealed image using the illumination unit (4) provided in the image capturing device (1).

  The n pieces of hidden image information acquired by imaging n times are taken into the authentication terminal (2), and the control unit (5) performs an S / N ratio improvement process which is one of gradation conversions (STEP02). ). This process is a method of reducing the influence of noise due to temporal fluctuations by adding the acquired data in the procedure shown in FIG. 8, and the S / N is multiplied by a half power (√n) of the number of acquisitions. The ratio is improved.

  Thereafter, in order to increase the density difference between the absorption spot in the predetermined wavelength region and the reflection spot in the predetermined wavelength region for an image in which the S / N ratio is improved and the influence of noise is reduced, one of the gradation conversions A contrast amplification process is performed (STEP 03). As shown in FIG. 9A, the low contrast image captured by capturing is small in the difference between the maximum value and the minimum value. Therefore, as shown in FIG. 9B, the density difference is expanded by a density correction function that extends the difference between the maximum value and the minimum value, thereby increasing the contrast of the image.

  As the density correction function, for example, the effective memory (8 bits) of the computer as shown in FIG. 10 is used to the maximum, and the minimum pixel value (black portion) and the maximum pixel value (white portion) become 0 and 255, respectively. Non-linear conversion may be performed by applying correction, extending the density gradation width, and weighting a quadratic expression or a specific density. Thus, by this processing, the contrast of the reflection-absorption image having a small density difference at the time of capturing an image in a predetermined wavelength region is enhanced, and an image that can be used for authentication processing in the next step is obtained.

  A Hartley conversion process is performed on the image on which the S / N ratio improvement and the contrast amplification process have been performed to generate an authentication image (STEP 04).

  After that, the authentication image obtained by the above processing is collated with the authentic image stored in advance in the storage unit (6) to authenticate whether the printed matter is authentic (STEP 05).

  The authentication result is notified to the notification unit (7) of the authentication terminal (2) (STEP06).

  Here, the processing order of the S / N ratio improvement processing and the contrast amplification processing is performed as described above, but the processing order is not limited to this, and other orders may be used.

  When an image pickup unit (3) of the image capturing device (1) having a very large number of pixels and a high resolution is used, the halftone dot structure of the printed matter is clearly picked up. When the QR code in FIG. 12A is captured by a high-resolution image capture device having a large number of pixels, in the QR code cell, as shown in FIG. Since it is a value and does not transmit light, it is recognized as a dark color. Other than the halftone dot portion in the cell, it is recognized as a light color because it is a high pixel value and transmits light. In this way, the QR code cell portion cannot be recognized as a solid region because of the large number of pixels and high resolution, and a region other than a halftone dot region having a low pixel value and a halftone dot having a high pixel value. It is clearly recognized as a collection of areas, and as a result, there is a possibility of affecting the authentication process.

  Therefore, an operation is performed on each pixel to output a result of adding all the density values of pixels inside a neighboring area (a set of images close to a certain pixel) centered on a certain pixel. By adding the values of many pixels, the pixel values are averaged and smoothed as shown in FIG. 12 (c), and this portion is composed of a halftone dot region having a low pixel value (dark color) and a high pixel value. A clear distinction from an area other than a halftone dot that is a pixel value (light color) is lost, and the area is re-expressed as a solid intermediate color between a dark color and a light color, so that it is possible to avoid an influence on subsequent authentication processing. At this time, the reduced density difference can be recovered by the contrast amplification process.

  Next, the authentication method of concealment information is demonstrated according to the flow shown in FIG. First, a concealed image having characteristics with respect to reflection or absorption in a predetermined wavelength region is imaged n times by the imaging unit (STEP07).

  Also in this case, as in the above STEP01, when the image is taken twice or more, the image pickup area can be prevented from changing by fixing the image pickup unit with a fixing device such as a tripod or a stand.

  Further, similarly to the above STEP01, it is possible to irradiate with desired illumination light corresponding to the concealed image using the illumination unit (4) provided in the image capturing device (1).

  Usually, when capturing a concealment image, it is possible to capture in a natural state such as sunlight. However, if the light is weak at night or indoors, there is a possibility that desired imaging cannot be performed. In such a case, as in the above STEP01, it is possible to irradiate with desired illumination light corresponding to the concealed image using the illumination unit (4) provided in the image capturing device (1). .

  As in the above STEP02, n hidden image information acquired by imaging n times is taken into the authentication terminal (2), and the control unit (5) improves the S / N ratio, which is one of the gradation conversions. Processing is performed (STEP08). This process is a method of reducing the influence of noise due to temporal fluctuations by adding the acquired data, and the S / N ratio is improved by a 1/2 power (√n) of the number of acquisitions.

  In addition, if there is illumination unevenness due to spatial non-uniformity of illumination conditions due to ambient light or density unevenness due to non-uniformity in the imaging area due to dark current etc., this is one of the gradation conversions to remove this effect. Density unevenness removal processing is performed (STEP09). As a method for removing the image component of the spatial density unevenness on the image, a method executed by subtracting or dividing the background image such as a shading correction processing method, or the frequency component of the density unevenness is cut using FFT or the like. There is a way.

  Thereafter, as in the above STEP 04, for an image in which the S / N ratio is improved and the influence of noise is reduced, the difference in density between the absorption portion in the predetermined wavelength region and the reflection portion in the predetermined wavelength region is increased. A contrast amplification process which is one of the gradation conversions is performed (STEP 10). Thus, by this processing, the contrast of the reflection-absorption image having a small density difference at the time of capturing an image in a predetermined wavelength region is enhanced, and an image that can be used for the decoding process in the next step is obtained.

  The acquired image is decoded, and concealment information concealed in the concealment image is acquired (STEP 11). The concealment information acquired by the above processing is compared with authentic information stored in advance in the storage unit (6) to authenticate whether the printed matter is authentic (STEP 12).

  The authentication result is notified by the notification unit (7) of the authentication terminal (2) (STEP 13).

  In this case as well, the processing order of the S / N ratio improvement processing, density unevenness removal processing, and contrast amplification processing is performed as described above. However, the processing order is not limited to this, and other orders may be used.

  When an image pickup unit (3) of the image capturing device (1) having a very large number of pixels and a high resolution is used, the halftone dot structure of the printed matter is clearly picked up. When the QR code in FIG. 12A is captured by a high-resolution image capture device having a large number of pixels, in the QR code cell, as shown in FIG. Since it is a value and does not transmit light, it is recognized as a dark color. Other than the halftone dot portion in the cell, it is recognized as a light color because it is a high pixel value and transmits light. In this way, the QR code cell portion cannot be recognized as a solid region because of the large number of pixels and high resolution, and a region other than a halftone dot region having a low pixel value and a halftone dot having a high pixel value. It is clearly recognized as a collection of areas, and as a result, there is a possibility of affecting the authentication process.

  Therefore, an operation is performed on each pixel to output a result of adding all the density values of pixels inside a neighboring area (a set of images close to a certain pixel) centered on a certain pixel. By adding the values of many pixels, the pixel values are averaged and smoothed as shown in FIG. 12 (c), and this portion is composed of a halftone dot region having a low pixel value (dark color) and a high pixel value. A clear distinction from an area other than a halftone dot that is a pixel value (light color) is lost, and the area is re-expressed as a solid intermediate color between a dark color and a light color, so that it is possible to avoid an influence on subsequent authentication processing. At this time, the reduced density difference can be recovered by the contrast amplification process.

  Next, specific embodiments will be described with reference to examples. The printed matter used in Examples 1, 2, 3, 4, 5 and 6 is prepared by concealing an image having a characteristic for reflection or absorption in the IR wavelength region as a concealed image. A method of imaging and authenticating will be described.

  FIG. 13A shows a visible image of a printed material used in Example 1, FIG. 13B shows an IR image including concealment information in the printed material, and FIG. 13C shows an S / N ratio. After the improvement process, FIG. 13D is an image after the contrast amplification process, and FIG. 13E is an image after the predetermined authentication process (the concealment information) for the image after the IR concealment image information is processed. is there.

  FIG. 14A shows a visible image of a printed material used in Example 2, FIG. 14B shows an IR image including concealment information in the printed material, and FIG. 14C shows an S / N ratio. After the improvement process, FIG. 14D shows the background density unevenness removal process, FIG. 14E shows the contrast amplification process, and FIG. 14F shows the image after the IR hidden image information is processed. The result of the decoding process (concealment information).

  An integrated authentication system and authentication method according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 7, and 13.

  The integrated authentication system includes an image capture device (1) and an authentication terminal (2). The image capturing device (1) includes an illumination unit (4), an imaging unit (3), a total reflection preventing sheet (17), and a support (18). The authentication terminal (2) includes a control unit (5). ), A storage unit (6), and a notification unit (7).

  First, a method for producing a printed material provided with a concealed image will be described. As shown in FIG. 19, a plurality of sets of one first region (14) and one second region (15, 16) adjacent to the first region are arranged. The periphery is surrounded by a plurality of first areas, and the first area is arranged with halftone dots of image (鳳凰) data configured using ink that does not contain an infrared absorbing pigment. The area was made larger. The second region (15, 16) is a second type region (15) configured using a black ink containing an infrared absorbing pigment and a black system configured using an ink not including an infrared absorbing pigment. A second area (16), and image data is networked by the second areas in the plurality of second areas in accordance with the ratio of the second area to the second area in each second area. The images are arranged with dots and cannot be recognized with the naked eye.

  This hidden image data is inputted with original image (background image) data f and binary image data (double circle) g which is a hidden image, and the original image data f is converted into a two-dimensional real data array by high-speed Hartley transform. F is converted into F, binary image data g ′ is generated by rearranging the binary image data g, and two-dimensional real data array H is generated by combining the two-dimensional real data array F and binary image data g ′. , And binary image data latent image data obtained by converting the two-dimensional real number data array H into binary image data latent image data by inverse high-speed Hartley transform.

  An authentication method will be described. The imaging condition for authenticating the concealed image in the printed material produced by the above method is set to 5 imaging times in consideration of the quality of the captured image, imaging time, and memory saving.

  The printed material is set at a predetermined position, and an IR image including the concealment information shown in FIG.

  Five IR images acquired by imaging with the IR camera five times are taken into the authentication terminal (2) as IR hidden image information.

  The authentication terminal (2) from which the five IR hidden image information is taken in adds up the five images. As a result, an image including IR concealment information whose S / N ratio is improved by √5 times is produced as shown in FIG.

  Thereafter, the authentication terminal (2) divides the image with improved S / N ratio from the previously acquired background image to generate an image from which density unevenness has been removed.

  Thereafter, the minimum pixel value (min) and the maximum pixel value (max) of the image with improved S / N ratio shown in FIG. 13C are searched. Then, as shown in FIG. 10, the effective memory (8 bits) of the computer is used to the maximum, and the correction is made so that the minimum pixel value (black portion) and the maximum pixel value (white portion) become 0 and 255, respectively. Is expanded to generate the image shown in FIG.

  A Hartley transform, which is a predetermined authentication process, is executed on the IR image including the concealment information shown in FIG. 13D, and the authentication image shown in FIG.

  The authentication image shown in FIG. 13E obtained by performing the image processing as described above is collated with the authentic image stored in advance in the storage unit to authenticate whether the printed matter is authentic. . The authentication result can be confirmed by the notification unit (7) of the authentication terminal (2).

  An integrated authentication system and authentication method according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 11, and 14.

  The integrated authentication system includes an image capture device (1) and an authentication terminal (2). The image capturing device (1) includes an illumination unit (4), an imaging unit (3), a total reflection preventing sheet (17), and a support (18). The authentication terminal (2) includes a control unit (5). ), A storage unit (6), and a notification unit (7).

  First, a method for producing a printed matter with concealment information will be described. As shown in FIG. 19, a plurality of sets of one first region (14) and one second region (15, 16) adjacent to the first region are arranged. The periphery is surrounded by a plurality of first areas, and the first area is arranged with halftone dots of image (鳳凰) data configured using ink that does not contain an infrared absorbing pigment. The area was made larger. The second region (15, 16) is a second type region (15) configured using a black ink containing an infrared absorbing pigment and a black system configured using an ink not including an infrared absorbing pigment. A second area (16), and image data is networked by the second areas in the plurality of second areas in accordance with the ratio of the second area to the second area in each second area. The images are arranged with dots and cannot be recognized with the naked eye.

  An authentication method will be described. The imaging condition for authenticating the concealed image in the printed material produced by the above method was set to 5 imaging times in consideration of the image quality of the captured image, imaging time, and use memory saving.

  The authentication terminal (2) in which the five pieces of background image information are taken in integrates the five background images, creates an image for removing density unevenness performed in the subsequent process, and stores this image in the storage unit. deep.

  Thereafter, the printed material is set at a predetermined position, and an IR image including the concealment information shown in FIG.

  Five IR images acquired by imaging five times with the IR camera are taken into the authentication terminal (2).

  The authentication terminal (2) in which the five IR hidden image information is taken in adds up the five images. As a result, an image including IR concealment information whose S / N ratio is improved by √5 times is produced as shown in FIG.

  Thereafter, the authentication terminal (2) divides the image with the improved S / N ratio from the previously acquired background image to generate an image from which density unevenness shown in FIG. .

  Thereafter, the minimum pixel value (min) and the maximum pixel value (max) of the image with improved S / N ratio shown in FIG. Then, as shown in FIG. 7, the effective memory (8 bits) of the computer is used to the maximum, and the minimum pixel value (black portion) and the maximum pixel value (white portion) are corrected to 0 and 255, respectively. The density gradation width is expanded to generate an image having the density gradation shown in FIG.

  The IR concealment image shown in FIG. 14E acquired by performing the image processing as described above and the IR concealment information shown in FIG. 14F are acquired by decoding the acquired image.

  The acquired IR concealment information shown in FIG. 14F and the authentic information stored in advance in the storage unit are collated to authenticate whether the printed matter is authentic. The authentication result can be confirmed by the notification unit (7) of the authentication terminal (2).

  In Example 2, in order to capture an image for removing density unevenness, a background image was captured by irradiating infrared light without setting a printed material, and the background image information was captured into the authentication terminal (2). However, with respect to this process, it is not necessary to perform the same process again on a printed matter of the same design that conceals the same information. When the background image information is taken into the authentication terminal (2), it is stored in the authentication terminal (2), and can be read out and used when authenticating a printed matter of the same design concealing the same information. The background image information is stored as an algorithm in the server (8) together with the printed matter. When there is a change or the like, the change information is transmitted from the server (8) to each authentication terminal (2).

  What has been described here is authentication for a printed matter having a halftone dot configuration, but it is also possible to perform similar authentication for a printed matter whose information is concealed using dedicated IR reflection and absorption inks.

  In the above-described two embodiments, the system using the IR reflection-absorption image has been described. However, it is also possible to perform authentication by taking a IR transmission-absorption image by IR transmission light by providing a transmission light unit in the terminal device. Is possible.

  In these examples, as a concealed image, a printed material produced by concealing an image having reflection or absorption characteristics in the IR wavelength region was used, and authentication was performed by capturing the IR concealed image. It is also possible to use this method for authentication based on images and transmitted light images of creased paper.

  A remote authentication system and authentication method for a certificate using a LAN according to an embodiment of the present invention will be described with reference to FIGS. 4, 6, and 15.

  In a remote authentication system using a LAN, an image capturing device (1) and a server (8) are connected via a network (9). The image capturing device (1) includes an imaging unit (3), a notification unit (7), a data transmission / reception unit (12), an operation unit (10), and a control unit (5). , A storage unit (6), an operation setting unit (11), a data transmission / reception unit (13), and a control unit (12).

  In the present embodiment, an IR camera having sensitivity in the IR region is used as a device including the imaging unit (3). In addition, as a method of notifying the authenticator of the result by the notification unit (7), a blue lamp is turned on when the authentication result is authenticated as positive, and a red lamp is turned on when the authentication result is authenticated as incorrect.

  The authentication method will be described with reference to the flow of FIG. First, an authentication image is captured by the IR camera on the image capturing device (1) side, the image is captured (STEP 14), and the captured IR image is transmitted to the server (8) side (STEP 15).

  The server (8) receives the IR image transmitted from the image capturing device (1) (STEP 18) and performs a predetermined authentication process (STEP 19). The predetermined authentication process is a predetermined decoding process corresponding to an encoding method when information is embedded in a printed matter. Depending on the image state, the above-described 1 averaging process, 2S / N ratio improvement process, and 3 density unevenness removal process are performed. Of the four contrast amplification processes, one or more processes may be performed before the decoding process.

  The authenticated result is transmitted to the image capture device (1) side (STEP 20).

  The image capture device (1) side receives the authentication result transmitted from the server (8) side (STEP 16), and if the authentication result is positive, the blue lamp is lit on the notification unit (7), and authentication is performed. If the result is incorrect, the red lamp is turned on (STEP 17).

  In this embodiment, since the printed material to be authenticated is printed with a concealed image having characteristics in the infrared region, the IR camera is used. However, the present invention is not limited to this, and the printed material to be authenticated. However, when the image is printed with a concealed image having characteristics in the ultraviolet region, a UV camera is used.

  In addition, as a method of notifying the result to the authenticator by the notifying unit (7), the form by lighting the lamp is used. However, the present invention is not limited to this, and a liquid crystal part is provided in the result notifying unit and the authentication result is displayed there. It is good also as a form which alert | reports an authentication result by sound and the sound.

  A remote authentication system and authentication method for a certificate using the Internet according to an embodiment of the present invention will be described with reference to FIGS. 5, 6, and 16.

  In the remote authentication system using the Internet, an image capturing device (1) and a server (8) are connected via a network (9). The image capturing device (1) includes an imaging unit (3), a notification unit (7), a data transmission / reception unit (12), an operation unit (10), and a control unit (5). , A storage unit (6), an operation setting unit (11), a data transmission / reception unit (13), and a control unit (12).

  In this embodiment, a certificate authority is assumed as the server (8). In addition, a commercially available mobile phone is used as an apparatus including the image pickup unit (3), and the notification unit (7) displays the result on the display screen of the mobile phone.

  The authentication method will be described with reference to the flow of FIG. First, the mobile phone on the image capturing device (1) side captures the two-dimensional code in which the URL of the certificate authority is embedded, and accesses the certificate authority (STEP 21) to start site connection (STEP 27).

  Next, an authentication image is captured by the mobile phone and the image is captured (STEP 22), and the captured image is transmitted to the server (8) side (STEP 23).

  The certificate authority receives the captured image transmitted from the image capture device (1) (STEP 28), and performs a predetermined authentication process (STEP 29). The predetermined authentication process is a predetermined decoding process corresponding to the encoding method when information is embedded in the printed matter. Depending on the image state, the above-mentioned averaging process, S / N ratio improvement process, and C density unevenness removal are performed. Of the processing and the contrast amplification processing, one or more processing may be performed before the decoding processing.

  The authenticated result is transmitted to the image capture device (1) side (STEP 30).

  The image capturing device (1) side receives the authentication result transmitted from the certificate authority (STEP 24), and the authentication result is displayed on the liquid crystal screen of the mobile phone (STEP 25).

  When the authentication is terminated, the access to the certificate authority is terminated (STEP 26), and the site connection is disconnected at the certificate authority (STEP 31).

  In this embodiment, the two-dimensional code in which the URL of the certificate authority is embedded is imaged and the certificate authority is accessed. However, the present invention is not limited to this. In the case of a printed matter in which the URL is directly described Can be accessed by directly typing its URL.

  Moreover, although it was set as the form which displays on a display screen of a mobile telephone as a method of notifying an authenticator by a notification part (7), it is not necessary to be limited to this, It is good also as a form which notifies an authentication result by sound. .

  A remote authentication system and method for certificate and personal authentication using the Internet according to an embodiment of the present invention will be described with reference to FIGS.

  In a remote authentication system using the Internet, an image capturing device (1) and a server (8) are connected via a network (9). The image capturing device (1) includes an imaging unit (3), a notification unit (7), a data transmission / reception unit (12), an operation unit (10), and a control unit (5). The storage unit (6), the operation setting unit (11), the data transmission / reception unit (13), and the control unit (12).

  In this embodiment, a certificate authority is assumed as the server (8). In addition, a commercially available mobile phone is used as an apparatus including the image pickup unit (3), and the notification unit (7) displays the result on the display screen of the mobile phone.

  An authentication method will be described with reference to the flowchart of FIG. First, the mobile phone on the image capturing device (1) side captures the two-dimensional code in which the URL of the certificate authority is embedded, and accesses the certificate authority (STEP 43) to start site connection (STEP 50).

  Next, an authentication image is captured by the mobile phone, the image is captured (STEP 44), and the captured image and the personal authentication code are transmitted to the server (8) side (STEP 45, STEP 46).

  The certificate authority receives the captured image and the personal authentication code transmitted from the image capturing device (1) (STEP 51, STEP 52), and first performs a predetermined printed material authentication process for the authentication of the printed material (STEP 53). The predetermined authentication process is a predetermined decoding process corresponding to the encoding method when information is embedded in the printed matter. Depending on the image state, the above-mentioned averaging process, S / N ratio improvement process, and C density unevenness removal are performed. Of the processing and the contrast enhancement processing, one or more processing may be performed before the decoding processing.

  It is determined whether or not the result of authentication is normal (STEP 54). If it is normal, person authentication processing is performed (STEP 55). The person authentication process is performed by comparing and collating the received personal authentication code with a card for authenticating an individual obtained by the printed matter authentication process described above.

  The authenticated printed matter authentication result and person authentication result are transmitted to the image capturing device (1) side (STEP 56).

  The image capturing device (1) side receives the authentication result transmitted from the certificate authority (STEP 47), and the printed matter authentication result and the person authentication result are displayed on the liquid crystal screen of the mobile phone (STEP 48).

Moreover, although it was set as the form which displays on a display screen of a mobile telephone as a method of notifying an authenticator by a notification part (7), it does not need to be limited to this, As a form which notifies an authentication result by the difference in sound Also good.

  When the authentication is terminated, the access to the certificate authority is terminated (STEP 49), and the site connection is disconnected at the certificate authority (STEP 57).

  A remote authentication system and authentication method for a certificate and personal authentication using a LAN according to an embodiment of the present invention will be described with reference to FIGS. 4, 6, and 17. FIG.

  In a remote authentication system using a LAN, an image capturing device (1) and a server (8) are connected via a network (9). The image capturing device (1) includes an imaging unit (3), a notification unit (7), a data transmission / reception unit (12), an operation unit (10), and a control unit (5). The storage unit (6), the operation setting unit (11), the data transmission / reception unit (13), and the control unit (12).

  In this embodiment, an IR camera having sensitivity in the IR region and a UV camera having sensitivity in the UV region are used as an apparatus including the imaging unit (3). In addition, as a method of notifying the authenticator of the result by the notification unit (7), a blue lamp is turned on when the authentication result is authenticated as positive, and a red lamp is turned on when the authentication result is authenticated as incorrect.

  An authentication method will be described with reference to the flowchart of FIG. First, an authentication image is captured by the IR camera and UV camera on the image capturing device (1) side and captured (STEP 32), and the captured IR image and UV image are transmitted to the server (8) side (STEP 33, STEP 34). ).

  The server (8) receives the IR image and the UV image transmitted from the image capturing device (1) (STEP 37, STEP 38), and first performs a predetermined printed material authentication process for the authentication of the printed material (STEP 39). The predetermined authentication process is a predetermined decoding process corresponding to the encoding method when information is embedded in the printed matter. Depending on the image state, the above-described averaging process, the S / N ratio improving process, and the C density unevenness are performed. One or more of the removal process and the contrast enhancement process may be performed before the decoding process.

  It is determined whether or not the result of authentication is normal (STEP 40). If it is normal, person authentication processing is performed next (STEP 41). The person authentication process is performed by comparing and collating the received personal authentication code with the code for authenticating the individual obtained by the printed matter authentication process described above.

  The authenticated printed matter authentication result and person authentication result are transmitted to the image capturing device (1) side (STEP 42).

  The image capture device (1) side receives the printed matter authentication result and the person authentication result transmitted from the server (8) side (STEP 35), and if both the printed matter authentication result and the person authentication result are positive, the notification unit (7 ), The blue lamp is turned on, and if the printed product authentication result is correct but the person authentication result is incorrect, the yellow lamp is turned on. If the printed product authentication result is incorrect, the red lamp is turned on (STEP 36).

  In this embodiment, since the image to be authenticated is printed with a concealed image having characteristics in the infrared region, an IR camera is used, and the code for personal authentication is concealed having properties in the ultraviolet region. Although the UV camera is used because it is printed as an image, the camera to be imaged is selected according to the print form of the image to be authenticated and the personal authentication code.

  Further, as a method of notifying the result to the authenticator by the notifying unit (7), the lamp is turned on. However, the present invention is not limited to this. The result notifying unit is provided with a small liquid crystal window, and the authentication result is provided there. May be displayed, or the authentication result may be notified by sound.

  In this embodiment, the two-dimensional code in which the URL of the certificate authority is embedded is imaged and the certificate authority is accessed. However, in the case of a printed matter in which the URL is directly described, the URL is directly entered and accessed. Is also possible.

  Moreover, although it was set as the form which displays on a display screen of a mobile telephone as a method of notifying an authenticator by a notification part (7), it is not necessary to be limited to this, It is good also as a form which notifies an authentication result by sound. .

  Further, the flow shown in FIGS. 7, 8, 15, 16, 17, and 18 is a single routine, but if there are a plurality of objects to be authenticated, the process is repeated. I do.

  Specifically, if there is no authentication object when the processing of STEP 06 is finished, the authentication processing is finished according to the flow, and if there is, the processing returns to STEP 01 and continues the processing. If there is no authentication object when the processing of STEP 13 ends, the authentication processing ends according to the flow, and if there is, the processing returns to STEP 07 and continues the processing. If there is no authentication object when the processing of STEP 17 ends, the authentication processing ends according to the flow, and if there is, the processing returns to STEP 14 to continue the processing. If there is no authentication object at the time when the processing of STEP 25 is completed, the authentication processing is terminated according to the flow, and if there is, the processing returns to STEP 22 and continues the processing. Further, if there is no authentication object when the processing of STEP 36 is completed, the authentication processing is terminated according to the flow, and if there is, the processing returns to STEP 32 and continues the processing. Further, when there is no authentication object at the time when the processing of STEP 48 is finished, the authentication processing is finished according to the flow, and when there is, the processing returns to STEP 44 and the processing is continued.

  In the best mode and embodiments for carrying out the present invention, an ink having a characteristic for reflection and absorption with respect to a concealed image by an ink composition having a characteristic for reflection, transmission and / or absorption in a predetermined wavelength region. Although only the case of using the composition is described, the present invention can be applied to any one of reflection, transmission, and absorption, or all combinations of two or more.

It shows about the form of the integrated authentication system in this invention. A configuration of an integrated authentication system according to the present invention will be described. (A) shows the front view of the imaging part in one Example of this invention, (b) shows the figure from the downward | lower direction, (c) shows the time of accommodation of an imaging part. It is a figure which shows the remote type | mold authentication system using LAN in one Example of this invention. It is a figure which shows the remote type | mold authentication system which used the internet in one Example of this invention. It is a figure which shows the structure of the remote type | mold authentication system using the network in this invention. The flow of the authentication method of the concealment image in one Example of this invention is shown. The process sequence in the S / N ratio improvement process in this invention is shown. (A) shows the image density distribution before contrast amplification processing in one embodiment of the present invention, and (b) shows the image density distribution after contrast amplification processing. The density correction function in this invention is shown. The flow of the authentication method of the concealment information in one Example of this invention is shown. (A) shows the image information when the concealed image of the printed matter in one embodiment of the present invention is taken into the imaging unit, (b) shows the pixel value of the XY portion of the image information, ( c) shows a pixel value obtained by averaging the pixel values of (b). (A) shows a printed matter in one embodiment of the present invention, (b) shows an IR image including concealment information in the printed matter, and (c) shows an image after (b) is subjected to S / N ratio improvement processing. (D) shows an image after (c) is subjected to contrast amplification processing, and (e) shows a concealed image obtained by subjecting (d) to Hartley transform. (A) shows a printed matter in one embodiment of the present invention, (b) shows an IR image including concealment information in the printed matter, and (c) shows after (b) is subjected to an S / N ratio improving process. (D) shows an image after (c) is subjected to background density unevenness removal processing, (e) shows an image after (d) is subjected to contrast amplification processing, and (f) shows (e). The concealment information obtained by decoding is shown. It is a figure which shows the authentication flow of the certificate using LAN in one Example of this invention. It is a figure which shows the authentication flow of the certificate using the internet in one Example of this invention. It is a figure which shows the flow of the certificate using LAN and personal authentication in one Example of this invention. It is a figure which shows the flow of the certificate using the internet in one Example of this invention, and a personal authentication. The 1st area | region and 2nd area | region in the image line structure of the printed matter used as the authentication object of this invention are shown. A conventional processing procedure for acquiring concealment information will be described.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image capture device 2 Authentication terminal 3 Imaging part 4 Illumination part 5 Control part 6 Storage part 7 Notification part 8 Server 9 Network 10 Operation part 11 Operation setting part 12, 13 Data transmission / reception part 14 1st area | region 15 Infrared absorptive pigment | dye 2a area 16 constituted by using black ink containing black 2b area 17 made of ink not containing infrared absorbing dye 17 Total reflection preventing sheet 18

Claims (6)

A plurality of sets of one first region and one second region adjacent to the first region are arranged, and each of the second regions is surrounded by the plurality of first regions. The first area has visible image data constituted by using a dot-free ink that does not contain an infrared-absorbing dye, and has a larger area than the second area. A second region of 2a configured using a black ink containing an absorptive pigment and a second region of 2b that is a black system configured using an ink not including an infrared absorbing pigment; The concealed image data is arranged as halftone dots in the second area of the plurality of second areas in accordance with the ratio of the second area to the second area in the area, and cannot be recognized by the naked eye. on a printed material subjected to Do concealed image, the hidden image A authentication method,
In a state in which the concealed image is in contact with the total reflection preventing sheet provided in the imaging device, the concealed image is captured n times by the imaging device to obtain n concealed image information,
A predetermined image correction process is performed on the acquired hidden image information,
The predetermined image correction process includes an S / N ratio improvement process for reducing the influence of noise by adding n pieces of the concealed image information, an absorption point in the predetermined wavelength region, and a reflection point in the predetermined wavelength region. Contrast amplification processing to increase the density difference of
A method for authenticating a concealed image, comprising performing a series of authentication of concealed images by collating an image after the image correction processing with a genuine image stored in advance. A plurality of sets of one first region and one second region adjacent to the first region are arranged, and each of the second regions is surrounded by the plurality of first regions. The first area has visible image data constituted by using a dot-free ink that does not contain an infrared-absorbing dye, and has a larger area than the second area. A second region of 2a configured using a black ink containing an absorptive pigment and a second region of 2b that is a black system configured using an ink not including an infrared absorbing pigment; The concealment image data in which concealment information is embedded in the region of the second a in a plurality of the second regions according to the ratio of the region of the second a and the region of the second b in the region of embed the hidden information can not recognize with the naked eye On a printed material subjected to concealed image, An authentication method of the concealment information,
In a state where the concealed image is in contact with the total reflection preventing sheet provided in the imaging device, the hidden image information is acquired n times by capturing the hidden image with the imaging device, and
A predetermined image correction process is performed on the acquired hidden image information,
The predetermined image correction process includes an S / N ratio improvement process for reducing the influence of noise by adding n pieces of the concealed image information, an absorption point in the predetermined wavelength region, and a reflection point in the predetermined wavelength region. Density unevenness removal processing to remove the influence of contrast amplification processing to increase the density difference and disturbance of illumination due to ambient light and illumination conditions and imaging unevenness in the imaging area,
The concealment information is acquired by decoding the image after the image correction processing, and the concealment information is authenticated in series by collating the acquired concealment information with previously stored authentic information. A method for authenticating concealment information characterized by:   3. The concealment information authentication method according to claim 1, wherein the predetermined image correction process includes an averaging process for averaging a low pixel value and a high pixel value of the concealment image information. A plurality of sets of one first region and one second region adjacent to the first region are arranged, and each of the second regions is surrounded by the plurality of first regions. The first area has visible image data constituted by using a dot-free ink that does not contain an infrared-absorbing dye, and has a larger area than the second area. A second region of 2a configured using a black ink containing an absorptive pigment and a second region of 2b that is a black system configured using an ink not including an infrared absorbing pigment; The concealed image data is arranged as halftone dots in the second area of the plurality of second areas in accordance with the ratio of the second area to the second area in the area, and cannot be recognized by the naked eye. on a printed material subjected to Do concealed image, the hidden image An authentication system for authenticating a series,
In a state where a concealed image printed with an ink composition having properties for reflection, transmission and / or absorption in a predetermined wavelength region is in contact with the total reflection preventing sheet provided in the image capture device and the concealed image, An image capturing device for capturing n times and acquiring n pieces of hidden image information;
Performs predetermined image correction processing on the acquired hidden image information, the predetermined image correction processing is the concealed image information of n reduce the effect of noise by adding the S / N ratio enhancement and the predetermined A contrast amplification process for increasing the density difference between the absorption spot in the wavelength region and the reflection spot in the predetermined wavelength region , and an average for averaging the low pixel value and the high pixel value of the hidden image information And a server for collating and authenticating the image after the image correction processing and a genuine image stored in advance,
An authentication system, wherein the image capturing device and the server are connected via a network, and the authentication of the concealed image is performed remotely in series. A plurality of sets of one first region and one second region adjacent to the first region are arranged, and each of the second regions is surrounded by the plurality of first regions. The first area has visible image data constituted by using a dot-free ink that does not contain an infrared-absorbing dye, and has a larger area than the second area. A second region of 2a configured using a black ink containing an absorptive pigment and a second region of 2b that is a black system configured using an ink not including an infrared absorbing pigment; The concealment image data in which concealment information is embedded in the region of the second a in a plurality of the second regions according to the ratio of the region of the second a and the region of the second b in the region of Embed the concealment information that cannot be recognized with the naked eye On a printed material subjected to concealed image, An authentication system for authenticating the hiding information in a series,
A state in which the concealed image embedded with concealment information printed with an ink composition having properties for reflection, transmission and / or absorption in a predetermined wavelength region is brought into contact with the concealment image and the total reflection preventing sheet provided in the imaging device An image capturing device for capturing n times with the imaging device and obtaining n pieces of hidden image information;
The acquired performs predetermined image correction processing on concealed image information, the predetermined image correction processing is the concealed image information of n reduced to S / N ratio enhancement effects of noise by adding the predetermined Contrast amplification processing to increase the density difference between the absorption spot in the wavelength region and the reflection spot in the predetermined wavelength region, and the density to remove the influence of illumination unevenness due to ambient light and illumination conditions and imaging unevenness in the imaging area Non-uniformity removal processing, further including an averaging process for averaging the low pixel value and the high pixel value of the concealed image information, acquiring concealment information by decoding the image after the image correction process, A server for verifying and authenticating the acquired concealment information and authentic information stored in advance,
An authentication system, wherein the image capturing device and the server are connected via a network, and the authentication of the concealment information is performed in series in a remote manner. The image capturing device is composed of an illumination-integrated imaging unit, a total reflection preventing sheet, and a support,
In the illumination-integrated imaging unit, an illumination unit for irradiating the printed matter with light is disposed around an imaging unit for imaging the concealed image,
The total reflection preventing sheet is made of a satin-finished film that transmits a specific wavelength in order to capture and image the contact with the concealed image of the printed matter,
The total reflection preventing sheet is foldably fixed to the lower part of the support, and one end of a support bar is swingably attached to the upper part of the support. The other end of the support bar 6. The authentication system according to claim 4 or 5, wherein the illumination-integrated imaging unit is fixedly attached.

Images