JP7722073B2 - Authenticity determination device and program - Google Patents

Description

The present invention relates to an authenticity determination device and a program therefor.

Financial institutions require identification by ID card (personal identification) such as a driver's license when opening an account, but there has been an increase in cases where ID cards are forged or altered in order to open accounts under the guise of another person for criminal purposes such as special fraud.

At typical financial institutions, users go to the institution and submit their ID card, and the financial institution then uses the submitted ID card to verify the user's identity in person. In this case, the ID card can be carefully observed, and any anomalies can be detected by the feel of the card.

Patent documents 1 and 2 also describe an authenticity determination device that determines the authenticity of an ID card from the image obtained by reading the face of the ID card with a reading device such as a scanner, and it is also possible to determine the authenticity of an ID card by reading a submitted ID card with a reading device such as a scanner.

Japanese Patent Application Laid-Open No. 2011-34535 Japanese Patent Application Publication No. 2019-117549

Recently, online banks and other online financial institutions have become common. Some of these financial institutions verify identity by taking a photo of the face of your ID card with a camera on a smartphone or other device and sending the image to the financial institution.

In this case, identity verification is performed solely by image, rather than face-to-face, so there is a need for methods to detect counterfeits. However, it is difficult to detect counterfeits from photographed images of ID cards, posing a challenge when applying online. In particular, in the case of identity cards that incorporate holograms as a countermeasure against counterfeiting, there have been cases where the accuracy of the detection has decreased due to the hologram being visible in the photographed image.

The present invention was made in consideration of the above problems, and aims to provide an authenticity determination device and the like that can suitably determine the authenticity of identification cards.

The first invention for solving the above-mentioned problems is an authenticity determination device for an identification card on which a hologram is formed, which has an authenticity determination means that uses a color image of a predetermined color component of a photographed image of the identification card to determine the authenticity of the identification card by comparing the outline of a character to be inspected, which is formed in a predetermined area of the identification card, with the outline of a correct character, and the authenticity determination means uses an image obtained by converting the photographed image to grayscale to determine the authenticity of the identification card by comparing the outline of the character to be inspected with the outline of a correct character, and if the identification card is not determined to be authentic, performs an authenticity determination using the color image .

The font of the characters printed on the ID card is predetermined. Therefore, authenticity determination is performed by comparing the outline of the character to be inspected, which is printed within a predetermined area of the ID card, with the outline of the correct character. This makes it possible to effectively distinguish between a genuine ID card in which the character to be inspected is printed in a predetermined font and a counterfeit ID card in which the character to be inspected is printed in a font other than the predetermined font. Furthermore, by using a color image based on a predetermined color component of the captured image for the determination, it is possible to prevent a decrease in determination accuracy due to the reflection of a hologram in the characters. Furthermore, determination using the color image is limited to cases in which the ID card is not determined to be genuine after determination using a grayscale image. If the influence of the reflection of a hologram is not expected, determination using the color image is not performed. This allows the overall authenticity determination to be completed in a short time.

The second invention is an authenticity determination device for an identification card on which a hologram is formed, which has an authenticity determination means that determines the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected, which is formed in a predetermined area of the identification card, with the outline of a correct character, and is characterized in that the authenticity determination means performs authenticity determination using a plurality of color images of each of the plurality of color components.
The font of the characters formed on the identification card is predetermined. Therefore, by comparing the outline of the character to be inspected, which is formed within a predetermined area of the identification card, with the outline of the correct character, authenticity determination can be performed, thereby suitably distinguishing between a genuine identification card in which the character to be inspected is formed in a predetermined font and a counterfeit identification card in which the character to be inspected is formed in a font other than the predetermined font. Furthermore, by using a color image based on a predetermined color component of the captured image for determination, a decrease in determination accuracy due to the reflection of a hologram on the characters can be suppressed. Furthermore, the effect of the reflection of a hologram may be apparent when viewing a color image based on one color component, but not when viewing a color image based on another color component. Therefore, the accuracy of authenticity determination can be improved by using multiple color images based on multiple color components.

A third invention is an authenticity determination device for an identification card on which a hologram is formed, which has an authenticity determination means that determines the authenticity of the identification card by using a color image of predetermined color components in a photographed image of the identification card and comparing the outline portion of the character to be inspected, which is formed in a predetermined range on the identification card, with the outline portion of the correct character, and the authenticity determination means calculates a vector from the origin to a contour pixel in the image of the character area of the correct character, detects a corresponding pixel at the end of the vector starting from the origin in the image of the character area of the character to be inspected, and if the corresponding pixel is not a contour pixel, searches for pixels in a range outside the corresponding pixel to calculate the difference in position between the detected contour pixel and the corresponding pixel as a difference vector, and determines the authenticity of the identification card using a determination value based on the difference vector.
The font of the characters formed on the identification card is predetermined. Therefore, by comparing the outline of the character to be inspected, which is formed in a predetermined area of the identification card, with the outline of the correct character to perform authenticity determination, it is possible to appropriately distinguish between a genuine identification card in which the character to be inspected is formed in a predetermined font and a counterfeit identification card in which the character to be inspected is formed in a font other than the predetermined font. Furthermore, by using a color image based on a predetermined color component of the captured image for determination, it is possible to suppress a decrease in determination accuracy due to the reflection of a hologram on the character. Furthermore, the difference between the outline of the character to be inspected and the outline of the correct character can be appropriately evaluated using a difference vector, allowing for appropriate authenticity determination.

The contour pixels of the character to be inspected are obtained as pixels of the second gradation value by performing processing in which, in a binary image in which the character is set to a first gradation value and the background is set to a second gradation value, if the pixel of interest has the first gradation value and all of the eight pixels surrounding the pixel of interest are not the first gradation value, and the pixel of interest is set to the first gradation value in other cases; and the contour pixels of a positive character are obtained as pixels of the second gradation value by performing processing in which, in a binary image in which the character is set to a first gradation value and the background is set to a second gradation value, if the pixel of interest has the first gradation value and all of the four pixels above, below, left, and right of the pixel of interest are not the first gradation value, and the pixel of interest is set to the first gradation value in other cases.
Since the above-mentioned method of calculating the difference vector searches for pixels in the character area to be inspected that correspond to the contour pixels of the positive character, the number of pixel searches corresponds to the number of contour pixels of the positive character, and the larger the number of contour pixels of the character to be inspected, the earlier one search will be completed. Therefore, as described above, by using strict criteria to reduce the number of contour pixels of the positive character and using looser criteria to increase the number of contour pixels of the character to be inspected, it is possible to quickly determine whether the identity card is genuine and to prevent erroneous determination of a genuine identity card as fake.

It is desirable that the authenticity determination device has a receiving means for receiving the captured image from a user terminal.
This makes it possible to construct an authenticity determination system using a network in which an authenticity determination device determines the authenticity of a photographed image of an identification card sent from a user terminal.

The fourth invention is a program for causing a computer to function as an authenticity determination device for an identification card having a hologram formed thereon, the authenticity determination device having an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a correct character , wherein the authenticity determination means uses an image obtained by converting the photographed image to grayscale and determines the authenticity of the identification card by comparing the outline of the character to be inspected with the outline of a correct character, and if the identification card is not determined to be authentic, performs an authenticity determination using the color image .
The fifth invention is a program for causing a computer to function as an authenticity determination device for an identification card having a hologram formed thereon, the authenticity determination device having an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a correct character, the program being characterized in that the authenticity determination means performs authenticity determination using a plurality of color images of each of the plurality of color components.
A sixth invention is a program for causing a computer to function as an authenticity determination device for an identification card on which a hologram is formed, the authenticity determination device having an authenticity determination means that determines the authenticity of the identification card by using a color image of predetermined color components in a photographed image of the identification card and comparing the outline portion of the character to be inspected, which is formed in a predetermined range on the identification card, with the outline portion of the correct character, wherein the authenticity determination means calculates a vector from the origin to a contour pixel in the image of the character area of the correct character, detects a corresponding pixel at the end of the vector starting from the origin in the image of the character area of the character to be inspected, and if the corresponding pixel is not a contour pixel, calculates the difference in position between the detected contour pixel and the corresponding pixel by searching for pixels in a range outside the corresponding pixel as a difference vector, and determines the authenticity of the identification card using a determination value based on the difference vector.

The present invention provides an authenticity determination device that can effectively determine the authenticity of personal identification cards.

FIG. 1 is a diagram showing an authenticity determination system 1. FIG. 2 is a diagram showing the hardware configuration of the authenticity determination device 3. FIG. 2 is a diagram showing the hardware configuration of a user terminal 5. FIG. 2 is a block diagram showing the functions of the authenticity determination device 3. FIG. 1 shows an ID card 10. 1 is a flowchart showing an outline of the processing of the authenticity determination system 1. An example of the ID card 10 photography screen. 10 is a flowchart showing an authenticity determination method. FIG. 2 is a diagram illustrating the extraction of a character range 200. 3A to 3C are diagrams illustrating the creation of a character image 300. 3A and 3B are diagrams for explaining binarization of a character image 300. 4A to 4C are diagrams illustrating notch removal from a binary image 400. 5A to 5C are diagrams for explaining the creation of an inspection image 500. FIG. 10 is a diagram illustrating calculation of a difference vector Vec. FIG. 10 is a diagram illustrating correction of a vector v. 10 is a flowchart showing the procedure for determining authenticity. FIG. 1 is a diagram illustrating reflection of a hologram.

The following describes in detail a preferred embodiment of the present invention with reference to the drawings.

(1. Authenticity Determination System 1)
1 is a diagram showing an authenticity determination system 1 having an authenticity determination device 3 according to an embodiment of the present invention. The authenticity determination system 1 is configured by connecting the authenticity determination device 3 and a user terminal 5 via a network so that they can communicate with each other. In the authenticity determination system 1, a photographed image of a user's ID card 10 is sent from the user terminal 5 to the authenticity determination device 3, and the authenticity determination device 3 determines the authenticity of the ID card 10 from the photographed image.

Figure 2 shows the hardware configuration of the authenticity determination device 3. The authenticity determination device 3 can be implemented by a computer configured by connecting a control unit 31, a memory unit 32, a communication unit 33, etc. via a bus or the like. However, this is not limited to this and various other configurations can be used as appropriate, and the authenticity determination device 3 can also be implemented by multiple computers.

The control unit 31 is composed of a CPU, ROM, RAM, etc. The CPU loads programs related to the processing of the authenticity determination device 3 stored in storage media such as the memory unit 32 and ROM into a work area on the RAM and executes them. The ROM is non-volatile memory and permanently stores programs such as the boot program and BIOS, as well as data. The RAM is volatile memory and temporarily stores programs and data loaded from the memory unit 32, ROM, etc., and also has a work area used by the control unit 31 to perform various processes.

The memory unit 32 is a hard disk drive, solid state drive, flash memory, etc., and stores the programs executed by the authenticity determination device 3 during the processing described below, data required for program execution, the OS, etc.

The communication unit 33 is a communication interface that mediates communication via a network and communicates with the user terminal 5.

The user terminal 5 is a terminal carried by the user, which takes a picture of the ID card 10 and transmits the captured image to the authenticity determination device 3. The user terminal 5 may be, for example, a mobile terminal such as a smartphone or tablet.

Figure 3 is a diagram showing the hardware configuration of the user terminal 5. As shown in Figure 3, the user terminal 5 is configured by connecting a control unit 51, a memory unit 52, a display unit 53, an input unit 54, a communication unit 55, a camera 56, an audio input/output unit 57, etc. via a bus or the like. However, this is not limited to this, and various other configurations can be used as appropriate.

The control unit 51, memory unit 52, and communication unit 55 are substantially the same as the control unit 31, memory unit 32, and communication unit 33 described above. The display unit 53 has a display device such as an LCD panel, and a touch panel is provided as the input unit 54 for inputting data to the user terminal 5. The audio input/output unit 57 includes a microphone and speaker used for audio input and output.

Camera 56 is an area camera composed of an optical lens, an imaging element such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor), an A/D (Analog/Digital) converter, etc. Camera 56 photoelectrically converts the subject image input through the optical lens using the imaging element to generate an analog image signal. The A/D converter then converts the analog image signal into digital image data.

Figure 4 is a block diagram showing the functions of the authenticity determination device 3. The authenticity determination device 3 has a receiving means 301, an authenticity determination means 302, etc.

The receiving means 301 allows the control unit 31 of the authenticity determination device 3 to receive a captured image of the ID card 10 from the user terminal 5 via the communication unit 33.

The authenticity determination means 302 determines the authenticity of the ID card 10 using a photographed image of the ID card 10 received by the control unit 31 of the authenticity determination device 3 from the user terminal 5. Details of this authenticity determination will be described later.

(2. ID Card 10)
In this embodiment, the ID card 10 is an identification card that is the subject of authentication determination. An identification card is a medium used for identity verification by financial institutions, mobile phone carriers, various administrative agencies, etc., such as a residence card, driver's license, My Number card, special permanent resident card, etc. In this embodiment, the ID card 10 is assumed to have a hologram formed thereon as an anti-counterfeit measure.

Figure 5 is a diagram showing an outline of the ID card 10 (residence card), and is a schematic illustration with some of the information on the face of the ID card 10 omitted.

Various information is printed on the ID card 10. For example, for a residence card, examples of the information on the card include the country of issue 11, residence number 12, date of birth of the card holder 13, facial image 14, residence status 15, whether or not there are employment restrictions 16, date of issuance of the card 17, and expiration date 18.

Of these, residence number 12, date of birth 13, facial image 14, residence status 15, presence or absence of employment restrictions 16, date of issue 17, expiration date 18, etc. are on-demand information that differ depending on the individual ID card 10.

On the other hand, characters such as "number," "date of birth," "residence status," "employment restriction status," "issue date," and "this card is..." that indicate the entry fields for residence number 12, date of birth 13, residence status 15, employment restriction status 16, date of issue 17, and expiration date 18, as well as the name of the card issuing country 11 and ID card 10 ("residence card"), are common to all ID cards 10. These characters are formed in advance in a predetermined position on the card substrate before the on-demand information is printed, and are called pre-printed portions.

ID card 10 is manufactured by printing the on-demand information on a card substrate on which the pre-printed portion has already been formed. The configuration of the on-demand information and pre-printed portion varies depending on the type of ID card 10, such as a residence card, driver's license, My Number card, or special permanent resident card.

(3. Overview of the processing of the authenticity determination system 1)
Fig. 6 is a flowchart showing an outline of the processing executed by the authenticity determination system 1. S1 to S2 and S7 to S8 in Fig. 6 are processing executed by the control unit 51 of the user terminal 5 by controlling each unit of the user terminal 5, and S3 to S6 are processing executed by the control unit 31 of the authenticity determination device 3 by controlling each unit of the authenticity determination device 3.

In this embodiment, the user first operates the user terminal 5 to launch a dedicated application program pre-stored in the memory unit 52. The user terminal 5 then displays a menu screen (not shown) on the display unit 53, activates the camera 56 in accordance with the user's selection on the menu screen, and photographs the face of the ID card 10 (S1).

Figure 7 shows an example of the ID card 10 capture screen at this time. In this embodiment, when the camera is started, instructions are displayed on the display unit 53 of the user terminal 5 to prompt the user to place the ID card 10 within a specified frame 531 before capturing the ID card 10.

When the user terminal 5 photographs the ID card 10, it transmits the photographed image to the authenticity determination device 3 (S2). The photographed image is a color image (RGB image) in which the pixel colors are determined by the gradation values of the R (red), G (green), and B (blue) components. The authenticity determination device 3 receives the photographed image of the ID card 10 (S3) and uses the photographed image to determine the authenticity of the ID card 10 (S4).

In this embodiment, authenticity is determined based on the fact that a genuine ID card 10 uses a specific font for the characters on the face of the card. Details of the authenticity determination method will be described later.

If the authenticity determination device 3 determines that the ID card 10 is not genuine (S5; NO), it transmits a message to the user terminal 5 indicating that the ID card 10 is not genuine (S6). When the user terminal 5 receives a message indicating that the ID card 10 is not genuine (S7), it displays this on the display unit 53 (S8) and ends the process.

On the other hand, if the authenticity determination device 3 determines that the ID card 10 is authentic (S5; YES), it completes the authenticity determination process. For example, when performing the above-mentioned authenticity determination as identity verification when opening an account at an online financial institution, after the authenticity determination process, user information (such as name and date of birth) on the face of the ID card 10 can be obtained from a photographed image of the ID card 10 as information required to open the account, and this information can be registered, and the user information can be stored in the memory unit 52.

(3-1. Authenticity determination based on character shape)
As described above, in this embodiment, the authenticity of the genuine ID card 10 is determined in step S4 (see FIG. 6) based on the shape of the characters, which are printed on the face of the genuine ID card 10 using a predetermined font.

In other words, the characters in the pre-printed portion of the ID card 10 and on-demand information are printed in a specified font within a specified range. Therefore, by comparing the shape of the characters within a specified range extracted from the photographed image of the ID card 10 with the correct characters used in that specified range on the genuine ID card 10, it is possible to identify a fake ID card 10 that uses a different font than the correct ID card 10.

Figure 8 is a flowchart showing the steps of the authenticity determination method in S4 (see Figure 6).

In this embodiment, in S4, a predetermined range of the captured image (RGB image) of the ID card 10 is first converted to grayscale to create a grayscale image. Furthermore, for the predetermined range of the captured image, the B component and R component are extracted as predetermined color components, and color images based on these color components, i.e., an image based on the gradation values of the B component (hereinafter referred to as the B image) and an image based on the gradation values of the R component (hereinafter referred to as the R image), are created (S401). The above-mentioned predetermined range can be set in advance as the range in which the characters to be inspected exist, and in this embodiment, it is the range in which the characters in the pre-printed portion described above are formed.

Next, the authenticity determination device 3 binarizes the grayscale image (S402). A grayscale image is an image in which pixel brightness is expressed using a gradation value between 0 and 255, with a gradation value of 0 being black and a gradation value of 255 being white. A binary image is an image in which the text portion is represented by black pixels (pixels with a first gradation value) and the background portion is represented by white pixels (pixels with a second gradation value). This is also true for other binary images, which will be described later. However, the specifications of grayscale images and the representation of binary images are not limited to those described above.

Next, the authenticity determination device 3 extracts the range of characters to be inspected (referred to as the character range) from the binarized image (S403).

The extraction method is not particularly limited, but in this embodiment, first, as shown in Figure 9(a), columns 101 and rows 102 containing black pixels are detected in the binarized image 100. Then, as shown in Figure 9(b), a region 101a is defined as a region where a predetermined number or more of columns 101 containing black pixels are consecutive and located near the center of the image 100, and a region 102a is defined as a region where a predetermined number or more of rows 102 containing black pixels are consecutive and located near the center of the image 100, and a range 100a consisting of regions 101a and 102a is extracted.

The authenticity determination device 3 performs the processes shown in Figures 9(a) and (b) on the extracted range 100a as necessary, and determines the final extracted range 200 as shown in Figure 9(c) as the character range. The above-mentioned predetermined number is, for example, 10 dots, but is not limited to this. Figure 10(a) shows an example in which the character to be inspected is the character "tome" in the pre-printed portion of the ID card 10, and the character range 200 of "tome" is extracted by the processes of S402 and S403.

As shown in Figure 10(b), the authenticity determination device 3 converts the resolution (dpi) of the original grayscale image 20 from which the character range 200 was extracted so that the character range 200 has a predetermined size (S404).

In this embodiment, the predetermined size is set to multiple numbers of dots in both the vertical and horizontal directions (in this embodiment, three numbers: 89, 90, and 91), and the processing of S405 to S410 described below is performed on multiple grayscale images 20' converted so that the character range 200 has these sizes. This is to reduce the influence of noise in the captured image and improve judgment accuracy. However, the predetermined size may be set to one, and the specific size is not particularly limited. The magnification during resolution conversion is set to a magnification that combines the above number of dots with the larger of the number of dots in both the vertical and horizontal directions of the character range 200 in the original grayscale image 20, and the resolution conversion can be performed using, for example, the bicubic method.

The authenticity determination device 3 then re-extracts the character to be inspected from the grayscale image 20' and creates a character image (S405). Here, as shown in Figure 10(c), the range of the character image 300 is set to a range whose center C coincides with the center of the character range 200 in the grayscale image 20' and is larger than the predetermined size (for example, 104 dots vertically and horizontally), but is not limited to this.

Next, the authenticity determination device 3 performs noise removal processing on the character image 300 (S406). In this embodiment, low-pass filtering and expansion/contraction processing are performed as noise removal processing, thereby removing high-frequency gradation value changes (noise).

In this embodiment, in S406, first, low-pass filtering is performed on the character image 300. Low-pass filtering is a known technique, but in this embodiment, for example, as shown in the following equation (1), the gradation value pn of each pixel in a certain range centered on a pixel of interest in the character image 300 is multiplied by a coefficient kn (weighting coefficient) corresponding to the position of each pixel to calculate the sum Σ(pn×kn), and this sum Σ(pn×kn) is then divided by the sum Σkn of the coefficients kn to obtain the gradation value p0′ of the pixel of interest, and this process is performed with each pixel of the character image 300 as the pixel of interest.
p0'=Σ(pn×kn)/Σkn…(1)

However, in this embodiment, the above sums Σ(pn×kn) and Σkn are calculated for pixels within the above range where the difference between their gradation value pn and the original gradation value p0 of the pixel of interest is less than a predetermined value. By not taking into account pixels with gradation values that differ greatly from the pixel of interest when calculating the sums Σ(pn×kn) and Σkn, low-pass filtering can be performed to prevent the edges around the characters from becoming blurred. The above predetermined value is, for example, 30, but is not limited to this.

In S406, the character portion of the character image 300 after low-pass filtering is further expanded or contracted. Expansion or contraction processes are known, but in this embodiment, for example, the process replaces the gradation value of a pixel of interest with the largest gradation value of pixels in a certain range centered on the pixel of interest, with each pixel of the character image 300 serving as the pixel of interest. After contracting the character portion in this way, the reverse process is performed, whereby the gradation value of the pixel of interest is replaced with the smallest gradation value of pixels in a certain range centered on the pixel of interest, with each pixel of the character image 300 serving as the pixel of interest. By expanding the character portion after contraction in this way, the outline of the character portion is shaped and noise is reduced.

Finally, the processing in S406 is terminated by performing a trimming process on the character image 300. The portion to be trimmed away is a predetermined width of the outer edge of the character image 300, and this width is determined according to the size of each fixed range set in the processing in S407.

Then, the authenticity determination device 3 performs binarization processing on the character image 300 (S407).

In this embodiment, a positive binary image of the character to be inspected (in this embodiment, "tome") is registered in advance in the memory unit 32 of the authenticity determination device 3 as the positive data to be used for authenticity determination. In S407, the threshold value for binarization is determined by comparison with the positive data to perform optimal binarization after comparison with the positive data.

More specifically, a histogram showing the number of pixels for each gradation value is first created for character image 300. Then, as shown in Figure 11(a), the range between the minimum and maximum gradation values V appearing in character image 300 is equally divided, and the division values Dn and the center value Cn of each division interval D are set. There are various methods for setting this, but in this example, the minimum gradation value V within division interval D is the division value Dn, and the maximum value of division value Dn is 1 greater than the maximum gradation value V appearing in character image 300. The center value Cn can also be calculated by averaging the upper and lower division values Dn. In reality, the number of division intervals D is approximately 16, but for the sake of explanation, the number is set to 3 in the example of Figure 11.

Next, for each divided section D, the center of gravity value Mn is calculated using the following formula (2) using each gradation value V within the divided section D and the number of pixels S for each gradation value V. Then, as shown in Figure 11(b), a new divided value Dn is calculated by averaging the center of gravity values Mn of the upper and lower divided sections D, and the divided value Dn (excluding the maximum and minimum values of the divided value Dn) is updated accordingly.
Mn = Σ(V・S)/ΣS…(2)

Then, as shown in Figure 11(c), a new center value Cn is calculated in the same manner as above using the new updated divided value Dn, and the center value Cn is updated accordingly. The processes in Figures 11(a) to (c) are repeated until there is no difference between the new center value Cn and the center value Cn before the update, and the divided value Dn at the end of the process (excluding the smallest divided value Dn) is set as the threshold. This results in multiple thresholds. Note that all values other than the center of gravity value Mn are integer values, and in the above process, the calculated values are rounded off or otherwise converted to integers as necessary.

The authenticity determination device 3 binarizes the character image 300 using each threshold value, compares the number of black pixels obtained in this process with the number of black pixels in the positive data, and determines the threshold value that produces the smallest difference as the final threshold value. In S407, the character image 300 is binarized using this threshold value, thereby enabling optimal binarization in comparison with the positive data.

Figure 12(a) is an example of a binary image 400 obtained by processing in S407, and the authenticity determination device 3 performs notch removal processing on this binary image 400 (S408).

The notches to be removed are fine (for example, one-dot) irregularities, and in this embodiment, for a certain range centered on a pixel of interest in binary image 400, as shown in Figure 12(b), when a pattern with a notch is detected, the pattern is replaced with a pattern without a notch, and this process is performed with each pixel of binary image 400 as the pixel of interest. There is a one-to-one correspondence between patterns with notches and patterns without notches, and multiple notches for white pixels and black pixels are prepared in addition to the example shown in Figure 12(b).

In this embodiment, the same replacement process is performed again, if necessary, on the binary image 400 after the above replacement process. This ensures that any small irregularities present in the binary image 400 are removed, improving the accuracy of authenticity determination.

Next, the authenticity determination device 3 performs character contour extraction processing on the binary image 400 after notch removal to create an inspection image (S409).

In this embodiment, as shown in Figure 13(a), for a pixel of interest in binary image 400, if the pixel of interest is black (first gradation value) and at least one of the eight pixels surrounding the pixel of interest is white (second gradation value), the pixel of interest is set to white; otherwise, the pixel of interest is set to black. This process is performed on each pixel of binary image 400 as the pixel of interest. This creates an inspection image 500 in which the outline pixels of characters are shown in white, as shown in Figure 13(b).

In contrast, in this embodiment, as shown in Figure 13(c), a similar contour extraction process is performed on positive data to obtain a positive contour image. However, the conditions for contour extraction are different from those described above. For a pixel of interest in positive data (binary image), if the pixel of interest is black (first gradation value) and at least one of the four pixels above, below, left, and right of the pixel of interest is white (second gradation value), the pixel of interest is set to white; otherwise, the pixel of interest is set to black. As a result, a positive contour image R is created for positive data as well, as shown in Figure 13(d), in which the contour pixels of the character are shown in white.

As can be seen from a comparison of Figures 13(a) and 13(c), the conditions for contour extraction are stricter for the positive data, which searches for white pixels within only the four pixels above, below, left, and right of the pixel of interest, than for the binary image 400, which searches for white pixels within the eight pixels surrounding the pixel of interest. As a result, the positive contour image R has fewer contour pixels than the inspection image 500.

The authenticity determination device 3 then compares the contour portion of the inspection image 500 with the contour portion of the correct contour image R, and calculates a determination value to be used for authenticity determination based on the difference between these contour portions (S410).

In this embodiment, as shown in Figure 14(a), rectangular regions circumscribing the contour pixels are first extracted as character regions t and r for each of the inspection image 500 and the positive contour image R. The character regions t and r are regions whose horizontal range is between the leftmost and rightmost contour pixels in the image (inspection image 500, positive contour image R) and whose vertical range is between the topmost and bottommost contour pixels in the image.

As shown in Figure 14(b), the authenticity determination device 3 calculates a vector v (xr, yr) from the origin o (Xr0, Yr0) of the character region r for the contour pixels of the character region r in the positive contour image R. Then, as shown in Figure 14(c), it detects the corresponding pixel 502 at the end of the vector v, which starts from the origin 501 (Xt0, Yt0) of the character region t in the inspection image 500.

If the corresponding pixel 502 is not a contour pixel, pixels are searched for in a certain range of the character area t centered on the corresponding pixel 502 (hereinafter sometimes referred to as the search range), starting from the vicinity of the corresponding pixel 502 and moving outwards. The specific search order is not particularly limited. The difference in position between the first detected contour pixel and the corresponding pixel 502 is then recorded in the memory unit 32 as a difference vector Vec(x,y). If the corresponding pixel 502 is a contour pixel, (0,0) is recorded as the difference vector Vec(x,y). Note that the origin o(Xr0,Yr0) and origin 501(Xt0,Yt0) are pixels in the upper left corners of the character areas r and t, respectively, but are not limited to this.

The authenticity determination device 3 calculates the difference vector Vec(x,y) for each contour pixel in the character region r of the positive contour image R using the above procedure, calculates the sum ΣVec(x,y), and calculates the average value avgVec(x,y) of Vec(x,y) using the following equation (3), where N is the total number of difference vectors Vec, i.e., the number of contour pixels in the character region r.
avgVec(x,y)=(1/N)ΣVec(x,y)…(3)

If the absolute values of both elements x and y of avgVec are less than 0.5, the authenticity determination device 3 terminates the processing, and determines the judgment value Result as the average value of the lengths of the difference vector Vec(x, y) when the avgVec was obtained, multiplied by 100, and calculates the judgment value Result using the following equation (4).
Result=(100/N)Σ(Vec(x) ² +Vec(y) ² ) ^1/2 …(4)

On the other hand, if the absolute value of either or both of the x and y elements of avgVec is 0.5 or greater, the authenticity determination device 3 corrects (offsets) the origin 501 of the inspection image 500 by the vector IntavgVec(x,y), which is obtained by rounding off each of the x and y elements of avgVec(x,y) to integers, as shown in Figure 14(d), and recalculates the difference vector Vec(x,y) for each contour pixel in the character region r of the positive contour image R using the procedure described above. Then, the determination value Result is calculated from these difference vectors Vec(x,y) using equation (4). Note that although equation (4) multiplies the average length of the difference vectors Vec(x,y) by 100, a value not multiplied by 100 can also be used as the determination value Result.

The processes of S405 to S410 are performed on the three grayscale images 20' obtained by the resolution conversion of S404 (see Figure 10(b)). The authenticity determination device 3 determines the smallest of the determination values Result obtained for each grayscale image 20' as the final determination value, and performs authenticity determination using that determination value Result (S411). The procedure for authenticity determination will be described later.

The basic calculation procedure for the judgment value Result is as described above, but in S410, it is also desirable to correct the vector v and the position (Xt0, Yt0) of the origin 501, taking into account the difference in size between the character area r in the positive contour image R and the character area t in the inspection image 500.

For example, to correct the vector v, the difference in size between the two character regions r and t is calculated as the horizontal magnification magX and the vertical magnification magY using the following equations (5) and (6), and the one of magX and magY that is closer to 1 is determined as the comparison magnification mag.
magX = (horizontal size of character area t)/(horizontal size of character area r) (5)
magY=(vertical size of character area t)/(vertical size of character area r) (6)

Then, as shown in Figure 15, the vector v(xr, yr) used to detect corresponding pixels 502 within the character region t of the inspection image 500 is corrected as the vector v·mag, where each element xr, yr is multiplied by the comparison magnification mag. Note that each element of the vector v·mag (xr·mag, yr·mag) is converted to an integer by rounding or other methods. The position of the origin 501 of the character region t of the inspection image 500 can also be corrected taking into account the above-mentioned comparison magnification mag. For example, the position of the origin 501 is offset so that it moves closer to or farther from the center of the character region t depending on the value of the comparison magnification mag.

Furthermore, with regard to the search for pixels in the character region t (see Figure 14(c)), the number of times each contour pixel in the character region t has been detected (the number of times it has been subject to calculation of the difference vector Vec) can be recorded, and during the search, the detection condition can be that the pixel being searched for is a contour pixel, and that the number of times that pixel has been detected is less than a predetermined value. For example, if the above predetermined value is 2, a pixel that has been detected 3 or more times will not be detected as a subject to calculation of the difference vector Vec, even if it is a contour pixel, and the next pixel will be searched for according to the search order described above.

Furthermore, if the contour pixel for which the difference vector Vec is to be calculated cannot be detected even after searching the entire search range, the difference vector Vec(x,y) can be recorded as (8,8) if the number of times the contour pixel could not be detected, including the search, is even, or (-8,-8) if the number of times is odd. By recording values with the same absolute value and opposite sign according to whether it is even or odd, the impact on calculating the sum ΣVec(x,y) of the difference vectors Vec can be reduced. Note that the absolute value can be determined taking into account the size of the search range, etc., and is not limited to 8 as described above. The size and shape of the search range are also not limited; for example, the search range could be a square or circular area.

(3-2. Procedure for authenticity determination using the judgment value Result)
As described above, in S411 (see FIG. 8), authenticity is determined using the determination value Result. This determination value Result is the final value obtained from the grayscale image 20 created in S401, but in this embodiment, the R image and B image created in S401 are also used for determination as needed, and the procedure for doing so will be described below.

Figure 16 is a flowchart showing the steps for determining authenticity in S411. In this embodiment, the determination value Resut is compared with a predetermined reference value, and if the determination value Result is smaller than the reference value (S4110; YES), the ID card 10 is determined to be authentic (S4111). The reference value can be set appropriately taking into account the accuracy of determination, etc.

On the other hand, if the judgment value Resut is equal to or greater than the reference value (S4110; NO), the ID card 10 is not deemed to be authentic. However, in this embodiment, as shown in FIG. 17, taking into consideration the possibility that the hologram is reflected in the captured image of the ID card 10, causing a large portion of the character in the binary image 400 to be missing, resulting in an incorrect calculation of the judgment value Result, if the judgment value Result is equal to or greater than a certain value (S4112; YES), the processes of S402 to S410 are performed on image B, and the judgment value Result is calculated based on a comparison between the outline of the character being inspected and the outline of the authentic character (S4113).

This is because, unlike grayscale image 20, which is created by grayscaling the RGB components of the captured image of ID card 10, when viewing the individual color components of the captured image of ID card 10, particularly the R and B components, the color of the hologram does not appear and the impact on the text may be minimal. For example, if the color of the hologram in the captured image is red, viewing the B component of the captured image will have less impact on the text, and if the color of the hologram is blue, viewing the R component will have less impact on the text. The above fixed value is set to a value greater than the reference value, and the specific value can be determined as appropriate taking into account factors such as judgment accuracy.

If the judgment value Result obtained in S4113 is not equal to or greater than the above-mentioned certain value (S4114; NO), the authenticity determination device 3 compares the judgment value Result with a predetermined reference value, and if the judgment value Result is smaller than the reference value (S4115; YES), it determines that the ID card 10 is authentic (S4116).

In addition, if the judgment value Result is smaller than a certain value in S4112 (S4112; NO) or if the judgment value Result is equal to or greater than the reference value in S4115 (S4115; NO), the ID card 10 is determined to be false (S4117).

On the other hand, if the judgment value Result is equal to or greater than a certain value in S4114 (S4114; YES), the processes of S402 to S410 are further performed on the R image, and a judgment value Result is calculated based on a comparison between the outline of the character being inspected and the outline of the correct character (S4118), and the smallest of the judgment values Result obtained from the grayscale image 20, B image, and R image is determined to be the final judgment value (S4119).

If the judgment value Result is smaller than the reference value (S4115; YES), the ID card 10 is determined to be true (S4116); if the judgment value Result is equal to or greater than the reference value (S4115; NO), the ID card 10 is determined to be false (S4117).

As described above, in this embodiment, the font of the characters formed on the ID card 10 is predetermined, and authenticity is determined by comparing the outline of the character to be inspected, which is formed in a predetermined area on the ID card 10, with the outline of the correct character. This makes it possible to effectively distinguish between a genuine ID card 10 in which the characters to be inspected are formed in a predetermined font and a fake ID card 10 in which the characters to be inspected are formed in a font other than the predetermined font.

The authenticity determination method of this embodiment is particularly effective for ID cards 10 that are difficult to copy simply because they incorporate anti-counterfeiting measures such as holograms, and can effectively distinguish counterfeit ID cards 10 that have been altered, such as by creating the card face from scratch. Furthermore, in this embodiment, by using a color image based on a specified color component of the captured image for determination, it is possible to prevent a decrease in determination accuracy due to the hologram being reflected in the text.

In addition, the determination using the color image is limited to cases where the ID card 10 is not deemed authentic after a determination using the grayscale image 20 has been made, and by not performing a determination using the color image if the influence of hologram reflections is not expected, the overall authenticity determination can be completed in a short time.

The effect of hologram reflections may be apparent when viewing a color image based on one color component, but not when viewing a color image based on another color component. Therefore, using multiple color images based on multiple color components (in this embodiment, the B and R components) can improve the accuracy of authenticity determination.

In this embodiment, the characters to be inspected are the characters in the pre-printed portion. For the characters in the pre-printed portion, the range in which each character will be printed is predetermined, so the correct characters to be compared are known in advance, and only a small amount of correct data is required. Furthermore, by comparing shapes, a fake ID card 10 can be detected not only when the font is different, but also when the characters themselves are different.

In addition, in this embodiment, the difference vector Vec calculated using the method described in Figure 14 etc. can be used to appropriately evaluate the difference between the outline of the character being inspected and the outline of the correct character, allowing for optimal authentication.

Here, the method of calculating the difference vector Vec described in Figure 14 etc. searches for pixels in the character area t to be inspected that correspond to the contour pixels of the positive character, so the number of pixel searches corresponds to the number of contour pixels of the positive character, and if the number of contour pixels of the character to be inspected is large, one search will end quickly. Therefore, as described in Figure 13 etc., by using strict criteria to reduce the number of contour pixels of the positive character and using looser criteria to increase the number of contour pixels of the character to be inspected, it is possible to quickly determine authenticity and reduce the risk of erroneously determining a genuine ID card 10 as fake.

However, the present invention is not limited to the embodiments described above. For example, in this embodiment, authenticity determination is performed as a means of identity verification when opening an account, but the application scenarios or purposes of authenticity determination in this embodiment are not particularly limited.

In this embodiment, the characters to be inspected are characters in the pre-printed portion, but they may also be characters in on-demand information. In this case, a known OCR (Optical Character Recognition) process is performed on a specified area of the captured image containing the characters to be inspected to recognize the characters, and the positive data corresponding to those characters is used to determine authenticity.

However, with on-demand information, the characters formed within a specified range of the captured image differ for each individual ID card 10, so a large amount of positive data must be prepared. However, on-demand information also includes ranges consisting only of numbers 0 to 9, such as date of birth, and ranges consisting only of letters A to Z. Therefore, when using characters within these ranges to determine authenticity, a relatively small amount of positive data is required.

In addition, in this embodiment, when binarizing the character image 300 in S407 (see Figure 8), the final threshold value was determined from among multiple threshold values by comparing the number of black pixels during binarization with the number of black pixels in positive data. However, for each binary image that has been binarized using all threshold values or multiple threshold values where the number of black pixels during binarization is close to the number of black pixels in positive data, the above-mentioned procedure can be followed up to calculating the judgment value Result using equation (4), and the smallest judgment value Result can be determined as the final threshold value.

In addition, while this embodiment tests for one character, it is also possible to test for multiple characters and ultimately determine that the ID card 10 is genuine if the above-described authenticity determination procedure determines that the ID card 10 is genuine for all characters, or if the number of characters that determine that the ID card 10 is genuine is a predetermined number or more.

In this embodiment, the G component of the captured image is not used in determining authenticity because the image based on the G component (G image) is similar to the grayscale image 20. However, it is also possible to omit determining authenticity from the grayscale image 20. In this case, the determination values Result calculated for each of the R image, B image, and G image in steps S402 to S410 can be compared, and the smallest of these can be compared with a reference value to determine authenticity.

Preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is clear that those skilled in the art will be able to conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally fall within the technical scope of the present invention.

1: Authenticity determination system 3: Authenticity determination device 5: User terminal 10: ID card 301: Receiving means 302: Authenticity determination means

Claims (8)

An apparatus for determining the authenticity of an identification card on which a hologram is formed,
an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a genuine character ;
The authenticity determination means uses an image obtained by converting the photographed image into a grayscale image, compares the outline of the character to be inspected with the outline of the correct character, and determines the authenticity of the identification card. If the identification card is not determined to be authentic, the authenticity determination means performs an authenticity determination using the color image.
An authenticity determination device characterized by: An apparatus for determining the authenticity of an identification card on which a hologram is formed,
an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a genuine character ;
The authenticity determination means performs authenticity determination using a plurality of color images for each of the plurality of color components.
An authenticity determination device characterized by: An apparatus for determining the authenticity of an identification card on which a hologram is formed,
an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a genuine character ;
The authenticity determining means
In the image of the character region of the positive character, a vector from the origin to the contour pixel is calculated;
In an image of a character region of the character to be inspected, a corresponding pixel at the end of the vector starting from the origin is detected;
If the corresponding pixel is not a contour pixel, a difference between the position of the contour pixel detected by searching for pixels in a range outside the corresponding pixel and the position of the corresponding pixel is calculated as a difference vector;
The authenticity of the personal identification card is determined based on a determination value based on the difference vector.
An authenticity determination device characterized by: The contour pixels of the character to be inspected are
In a binary image in which the character has a first gradation value and the background has a second gradation value, if the pixel of interest has the first gradation value and at least one of the eight pixels surrounding the pixel of interest has the second gradation value, the pixel of interest is set to the second gradation value, and in other cases, the pixel of interest is set to the first gradation value, thereby obtaining a pixel of the second gradation value;
The positive character contour pixels are
The authenticity determination device according to claim 3, characterized in that in a binary image in which the character is a first gradation value and the background is a second gradation value, if the pixel of interest has the first gradation value and at least one of the four pixels above, below, left, and right of the pixel of interest has the second gradation value, the pixel of interest is set to the second gradation value, and in all other cases, the pixel of interest is set to the first gradation value, thereby obtaining a pixel of the second gradation value. 5. The authenticity determining device according to claim 1 , further comprising a receiving means for receiving the photographed image from a user terminal. Computer,
An apparatus for determining the authenticity of an identification card on which a hologram is formed,
A program for causing the device to function as an authenticity determination device having an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a correct character ,
The authenticity determination means uses an image obtained by converting the photographed image into a grayscale image, compares the outline of the character to be inspected with the outline of the correct character, and determines the authenticity of the identification card. If the identification card is not determined to be authentic, the authenticity determination means performs an authenticity determination using the color image.
A program characterized by: Computer,
An apparatus for determining the authenticity of an identification card on which a hologram is formed,
A program for causing the device to function as an authenticity determination device having an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a correct character ,
The authenticity determination means performs authenticity determination using a plurality of color images for each of the plurality of color components.
A program characterized by: Computer,
An apparatus for determining the authenticity of an identification card on which a hologram is formed,
A program for causing the device to function as an authenticity determination device having an authenticity determination means for determining the authenticity of the identification card by using a color image of a predetermined color component of a photographed image of the identification card and comparing the outline of a character to be inspected formed in a predetermined area of the identification card with the outline of a correct character ,
The authenticity determining means
In the image of the character region of the positive character, a vector from the origin to the contour pixel is calculated;
In an image of a character region of the character to be inspected, a corresponding pixel at the end of the vector starting from the origin is detected;
If the corresponding pixel is not a contour pixel, a difference between the position of the contour pixel detected by searching for pixels in a range outside the corresponding pixel and the position of the corresponding pixel is calculated as a difference vector;
The authenticity of the personal identification card is determined based on a determination value based on the difference vector.
A program characterized by: