JP7384502B1 - Authenticity determination device, authenticity determination method, and authenticity determination program - Google Patents

Abstract

An object of the present invention is to provide an authenticity determination device, an authenticity determination method, and an authenticity determination program that can easily determine authenticity. [Solution] An authenticity determination device 20 includes an imaging unit 6 that reads a subject on which a read area including a latent image is printed in advance as image information, and an image processing unit that extracts latent image information from the image information and makes it visible. unit 7, a coloring processing unit 12 that converts the manifested latent image information into chromatic colors, and determines whether or not the specific image latent image included in the latent image matches the specific image information stored in advance. and a display processing unit 14 that displays the manifested latent image information on the display screen unit 15 at the same time as the latent image is read by the imaging unit 6. When the information matches the information, the display processing unit 14 is activated. [Selection diagram] Figure 1

Description

The present invention relates to an authenticity determination device, an authenticity determination method, and an authenticity determination program that can determine the authenticity of a photographic subject.

Conventionally, as anti-counterfeiting technology, there is a technique in which a latent image appears on a copy when it is copied by a copying machine (see Patent Document 1 below, hereinafter, the technology described in Patent Document 1 will be referred to as "Publication Publication 1 Invention") ). According to the invention in Document Publication 1, the line width of the line pattern that becomes a latent image is 1/2 of the line pattern of the background, and the line pattern of the background and the latent image are There is a right angle relationship with the parallel line pattern.

The anti-counterfeiting paper according to the invention in Document Publication 1 is difficult to visually recognize the latent image, so the latent image is not noticeable, but when it is copied, only the latent image becomes visible, so it cannot be used as a copy for the purpose of forgery. I understand that there is something. Therefore, it can be expected that counterfeiting due to copying will be deterred.

JP2003-237211A

By the way, according to the first invention in the literature, it is easy to determine whether or not it is a forged copy, but it is difficult to determine whether or not an original item that is not a copy is genuine in the first place. Have difficulty. It is difficult to determine the authenticity of a banknote or the like with the naked eye, and the anti-counterfeiting technology as disclosed in the Publication No. 1 invention is not suitable for three-dimensional objects that cannot be copied using a copying machine.

The present invention has been proposed in view of the above circumstances. That is, the object is to provide an authenticity determination device, an authenticity determination method, and an authenticity determination program that can easily determine authenticity.

The authenticity determination device according to the present invention includes an imaging unit that reads a subject on which a read area including a latent image is printed in advance as image information, and a latent image image information that is the image information of the latent image from the image information. an image processing unit that extracts and makes the latent image information visible, and a display processing unit that displays the made latent image information on the screen, superimposing it on the latent image at the same time as the image pickup unit reads the latent image information. Features.

The authenticity determination device according to the present invention includes a determination unit that determines whether a specific image included in the read area and specific image information stored in advance in association with the specific image match. However, it is preferable that the display processing section operates when the specific image matches the specific image information.

In the authenticity determination device according to the present invention, it is preferable that the latent image includes a specific image latent image portion that is the specific image.

In the authenticity determination device according to the present invention, it is preferable that the image processing section includes a coloring processing section that converts the manifested latent image information into a chromatic color.

In the authenticity determination device according to the present invention, the image processing section includes an extraction processing section that extracts a low frequency component from the image information, a binarization processing section that binarizes the image information, and a binarization processing section that binarizes the image information. It is preferable to include an expansion/contraction processing section that performs expansion/contraction processing on the image information.

In the authenticity determination device according to the present invention, the read area includes the latent image that is composed of a flat mesh or parallel lines and can be copied by a copying machine, and the latent image that is composed of a flat mesh or parallel lines and that cannot be copied by a copying machine. a background inferior to the latent image, and the lines of the latent image have a width of 0.05 to 0.35 mm and a pitch of 0.2 to 0.8 mm, or a flat mesh of the latent image, Preferably, the diameter is 0.1 to 0.5 mm and the pitch is 0.2 to 0.8 mm.

The authenticity determination method according to the present invention includes a printing procedure for printing a read area including a latent image on a subject, an imaging procedure for reading the subject as image information, and the image information of the latent image from the image information. an image processing procedure for extracting and making latent image information visible; and a display processing procedure for displaying the manifested latent image information on a screen superimposed on the latent image at the same time as it is read by the imaging procedure. It is characterized by passing through.

The authenticity determination program according to the present invention includes an imaging procedure for reading a subject on which a read area including a latent image is printed in advance as image information, and a latent image image information that is the image information of the latent image from the image information. A computer is caused to execute an image processing procedure for extracting and making visible the latent image information, and a display processing procedure for displaying the revealed latent image information on the screen superimposed on the latent image at the same time as it is read by the imaging procedure. , is characterized by.

The authenticity determination device according to the present invention includes an imaging unit that reads a subject on which a read area including a latent image is printed in advance as image information, and an imaging unit that extracts latent image information that is image information of the latent image from the image information. and a display processing section that displays the visualized latent image information on the screen superimposed on the latent image simultaneously with the reading by the imaging section. Therefore, the latent image information is extracted from the image information of the subject, and the latent image information is displayed on the screen in real time, overlapping the latent image. In other words, image information is not recorded as a still image or video and then processed, but is read and processed at the same time, and the latent image information is made visible and appears on the screen. The image looks outstanding. Therefore, it is not only easy to handle, but also easy to determine authenticity. Furthermore, since the latent image is not visible (or difficult to see), it does not impede the beauty of the subject.

The authenticity determination device according to the present invention includes a determination unit that determines whether a specific image included in a region to be read and specific image information stored in advance in association with the specific image match. When the specific image matches the specific image information, the display processing section is activated. For a subject on which a specific image is not printed, the display processing section does not operate, so the manifested latent image information does not appear on the screen. Therefore, since it can be determined that an object in which no visible latent image information appears is a fake, it is easy to determine the authenticity.

The authenticity determination device according to the present invention includes a specific image latent image portion in which the latent image is a specific image. That is, since the specific image is printed as a latent image, the specific image does not interfere with the beauty of the subject.

In the authenticity determination device according to the present invention, the image processing section includes a coloring processing section that converts the manifested latent image information into chromatic colors. By converting the latent image information into chromatic colors, it appears prominently on the screen. Therefore, it is easy to determine authenticity.

In the authenticity determination device according to the present invention, the image processing unit includes an extraction processing unit that extracts low frequency components from image information, a binarization processing unit that binarizes the image information, and an extraction processing unit that extracts low frequency components from image information. It has an expansion and contraction processing section that performs expansion and contraction processing. Since the latent image information corresponds to a low frequency component since the change in brightness is gradual, the latent image information is made visible by the extraction processing section. Furthermore, the image information is binarized by the binarization processing unit, and further subjected to expansion/contraction processing by the expansion/contraction processing unit, thereby making latent image information visible. Therefore, latent image information can be visualized with high precision.

The authenticity determination device according to the present invention has a latent image in which the read area is made up of a flat screen or lines and can be copied by a copying machine, and a latent image that is made up of a flat screen or lines and cannot be copied by a copying machine. The lines of the latent image have a width of 0.05 to 0.35 mm and a pitch of 0.2 to 0.8 mm, or the flat mesh of the latent image has a diameter of 0.1 to 0. .5 mm, pitch 0.2 to 0.8 mm. Therefore, a counterfeit-preventing printed matter on which a latent image composed of flat mesh or parallel lines is printed can be read. It is simple because existing technology can be used.

The authenticity determination method according to the present invention includes a printing procedure for printing a read area including a latent image on a subject, an imaging procedure for reading the subject as image information, and a latent image information, which is image information of the latent image, from the image information. The process includes an image processing procedure for extracting and making visible the latent image information, and a display processing procedure for displaying the revealed latent image information on the screen superimposed on the latent image at the same time as it is read by the imaging procedure. Therefore, the same effect as the above-described authenticity determination device is achieved.

The authenticity determination program according to the present invention includes an imaging procedure for reading an object on which a reading area including a latent image is printed in advance as image information, and extracting latent image information, which is image information of a latent image, from the image information. The computer is caused to execute an image processing procedure for making the latent image information visible by using the imaging procedure, and a display processing procedure for displaying the revealed latent image information on the screen superimposed on the latent image at the same time as it is read by the imaging procedure. Therefore, the same effect as the above-described authenticity determination device is achieved.

FIG. 1 is a schematic diagram of the hardware configuration of an authentication device according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a subject determined by the authenticity determination device according to the embodiment of the present invention. FIG. 3 is a flowchart showing a processing flow by the authenticity determination device according to the embodiment of the present invention. FIG. 4 is a schematic diagram of image information read by the imaging unit. FIG. 5 is a first schematic diagram showing the process of image processing. FIG. 6 is a second schematic diagram showing the process of image processing.

EMBODIMENT OF THE INVENTION Below, the authenticity determination apparatus based on embodiment of this invention is demonstrated based on drawing. FIG. 1 shows a schematic hardware configuration of the authenticity determination device 20.

As shown in FIG. 1, the authenticity determination device 20 includes at least a control section (CPU 1), a storage section 2, an input section (imaging section 6), an output section (display screen section 15), and the like. The storage unit 2 includes a ROM 3, a RAM 4, an HDD and/or an SSD 5, and the like. The input section is, for example, an imaging section 6 composed of a camera lens, a charge coupled device (CCD), etc., and the output section is, for example, a display screen section 15 such as a liquid crystal display or an organic EL display. . In accordance with the program stored in the ROM 3, the CPU 1 uses the RAM 4, which stores OS (Operating System) programs and part of application programs, to process the imaging unit 6, image processing unit 7 (extraction processing unit 8, binary processing unit 8, The color processing section 9, the expansion/contraction processing section 10, the manifestation processing section 11, the coloring processing section 12), the determination section 13, the display processing section 14, and the display screen section 15 are controlled.

The authenticity determination device 20 can be realized by a hardware configuration, a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an MPU (Micro Processing Unit), and software. For example, in the case of realizing it by software, it can actually be realized by configuring a computer with a CPU 1, a GPU, an MPU, a ROM 3, a RAM 4, etc., and running a program stored in the ROM 3 or RAM 4.

Therefore, the functions of each part 6 to 15 include an imaging procedure, an image processing procedure (extraction processing procedure, binarization processing procedure, expansion/contraction processing procedure, revealing processing procedure, coloring processing procedure), determination procedure, display processing procedure, and display An authenticity determination program that operates as a procedure is realized via a mobile terminal such as a smartphone or tablet, or a computer (hereinafter referred to as a "mobile terminal, etc."). In addition, the authenticity determination program may be recorded on a recording medium such as a CD-ROM, and the authenticity determination program may be loaded into a mobile terminal (for example, the authenticity determination program loaded on a computer may be loaded onto the mobile terminal). It can also be achieved. As the recording medium, in addition to the CD-ROM, for example, a hard disk, a flexible disk, an optical disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, a DVD, etc. can be used.

The authenticity determination device 20 may function as an ASP (Application Service Provider), and can also be realized by downloading an authenticity determination program to a mobile terminal or the like via a network such as the Internet. Furthermore, these hardware and software resources can also be provided in a form such as a cloud that can be accessed via a network.

Next, the subject to be determined by the authenticity determining device 20 will be explained based on the drawings. FIG. 2 is a schematic diagram of a subject 30, and the subject 30 is, for example, an anti-counterfeit printed matter. Note that the subject 30 includes, for example, a part of a two-dimensional plane such as a document, a ticket, a label, a book, or a wrapping paper, and a three-dimensional three-dimensional object such as a box or container.

A reading area 34 including a latent image 36 and a background 33 is printed on the subject 30 in advance. The latent image 36 includes a latent image portion 31 and a specific image latent image portion 32. The printed characters 35 are printed on the read area 34 depending on the purpose of the subject 30. Note that the printed characters 35 may be a pattern or the like, or may be printed on the latent image 36. Although the latent image 36 is difficult to visually recognize with the naked eye, it can be copied by a copying machine (not shown), and the background 33 can be copied by a copying machine to a lesser degree than the latent image 36. Therefore, if the subject 30 is copied, only the latent image 36 will appear on the copy, and the background 33 will not be output. Note that "the degree of copying by a copying machine is inferior to that of the latent image 36" means, for example, when copying by a copying machine is impossible and the copy is not completed completely, or when copying by a copying machine is possible but it is not visible to the naked eye. This includes cases in which it is not visible, cases in which it is visible with the naked eye but only slightly, and cases in which it is visible with the naked eye but is not clearer than the latent image 36.

The latent image 36 is represented by lines that can be reproduced by a copying machine, for example, and is composed of a line group of 30 to 120 lines/inch. The parallel lines have a width of 0.05 to 0.35 mm and a pitch of 0.2 to 0.8 mm, preferably a width of 0.1 mm and a pitch of 0.5 (≒0.508) mm. It is. The number of lines in this case is 50 lines/inch. On the other hand, the background 33 is represented by flat dots, which are small dots that do not meet the reproduction capability of copying, and are composed of dots of 150 to 300 lines/inch. The background 33 has a dot density of, for example, 5 to 25 percent (%). The area ratio of both is, for example, 5 to 25 percent (%). According to these line numbers and area ratios, even if the background 33 is visible as a uniform surface, it is difficult to reproduce with a copying machine, and the latent image 36 is visible as a uniform surface. However, it is difficult to visually recognize the latent image 36 and can be copied by a copying machine.

Here, the number of lines refers to the number of lines that exist in one inch, and when the area ratio is the same, the larger the number of lines, the smaller the dots (halftone dots) formed, line) becomes thinner. The larger the difference in the number of lines, the more conspicuous the boundary tends to be. Moreover, the area ratio refers to the ratio of the area of halftone dots or parallel lines in a unit area. Therefore, for example, in the halftone dot grid created based on 150 lines, 15% grid lines, and 42 lines, 15% grid lines, the background 33 is realized in the flat grid area, and in the grid area, A latent image 36 is realized.

Note that the latent image 36 may be a collection of large dots that can be reproduced by a copying machine, and is represented by, for example, a flat mesh that can be reproduced by a copying machine, and is composed of a 50-line/inch flat mesh. The flat mesh has a diameter of 0.1 to 0.5 mm and a pitch of 0.2 to 0.8 mm, preferably a diameter of 0.3 mm and a pitch of 0.5 (≒0.508) mm. be. On the other hand, the background 33 may be a group of lines whose reproduction capability is insufficient. In this case, the line group is composed of lines thinner than the parallel lines used in the latent image 36, or constructed at a different angle from the parallel lines used in the latent image 36.

When the latent image 36 is input as image information to the authenticity determination device 20, the latent image portion 31 and the specific image latent image portion 32 are made visible through image processing by the authenticity determination device 20 and appear on the display screen portion 15. At this time, the latent image section 31 and the specific image latent image section 32 become visible and appear on the display screen section 15 only when the information recorded in advance in the authenticity determination device 20 and the specific image latent image section 32 match. Note that the specific image latent image portion 32 is any figure, symbol, character, or a combination of a plurality of these.

Next, each part 6 to 15 will be explained based on the drawings together with the procedure for processing the subject 30 by the authenticity determining device 20. FIG. 3 shows an outline of the processing flow of the authenticity determination device 20. FIG. 4 shows image information 37 of the subject 30. 5 and 6 show the image processing process. Although the grid squares in FIG. 4 and the like represent pixels, they are simplified and do not accurately represent the original resolution of the authenticity determination device 20.

In FIG. 3, in step S1, an imaging procedure by the imaging unit 6 is executed. In the imaging procedure, light reflected by the subject 30 (reading area 34) passes through a camera lens, forms an image on a CCD, and is converted into an electrical signal. This electrical signal is read as image information 37 and input to the image processing section 7, as shown in FIG.

In steps S2 to S6, an image processing procedure by the image processing section 7 is executed. In the image processing procedure, latent image information 38, which is image information of the latent image 36, is extracted from the image information 37 of the subject 30 and made visible. The image processing section 7 includes an extraction processing section 8, a binarization processing section 9, an expansion/contraction processing section 10, a manifestation processing section 11, and a coloring processing section 12 (see FIG. 1).

In step S2, the extraction processing unit 8 executes filter processing. In the filter processing, any low frequency component among the frequency components of the image information 37 is extracted by a low pass filter or a band pass filter. Compared to the printed image information 39 of the printed characters 35, the latent image information 38 has a gradual change in brightness and corresponds to a low frequency component. Therefore, by performing filter processing, the image information 37 Print image information 39 and the like are removed from the image, and latent image information 38 remains (see FIG. 5).

In step S3, the binarization processing unit 9 binarizes the image information 37 using a binarization processing procedure. In the binarization processing procedure, an optimal threshold value is set by, for example, a discriminant analysis method or adaptive threshold processing, and the image information 37 is converted to white or black using the threshold value as a boundary. For example, in the case of monochrome image information with 256 tones, the latent image information 38 has a larger pixel value than the background image information 40, which is image information of the background, so it is converted to black. Conversely, the background image information 40 is converted to white (see FIG. 6).

In step S4, the expansion/contraction processing unit 10 performs expansion/contraction processing on the binarized image information 37 using an arbitrary kernel according to an expansion/contraction processing procedure. Therefore, the number of white pixels increases or decreases, and the latent image information 38 of black pixels stands out.

In step S5, the manifestation processing unit 11 generates a histogram of the image information 37 and extracts only the latent image information 38 according to the manifestation processing procedure. That is, if the image information 37 includes a low frequency component other than the latent image information 38, this low frequency component is noise, so it is distinguished from the latent image information 38, and only the latent image information 38 is included. Extracted.

By executing the processes of steps S2 to S5 described above, the latent image information 38 can be made visible with high precision.

In step S6, the coloring processing section 12 converts the latent image information 38 made visible by the image processing section 7 into a chromatic color by coloring processing. The chromatic color is arbitrary, and examples thereof include red, green, and blue.

In step S7, the determination unit 13 determines whether the specific image latent image portion 32 and the specific image information match according to a determination procedure. The specific image information is stored in advance in the storage unit 2 in association with the image information 37 of the specific image latent image section 32. The latent image information 38 includes information corresponding to the specific image latent image part 32 (hereinafter referred to as "specific part image information 41"), and the specific part image information 41 and the specific image information match. If so, the process of step S8 is executed. On the other hand, if the latent image information 38 does not include the specific part image information 41 or if the specific part image information 41 included in the latent image information 38 does not match the specific image information, step S11 processing is executed.

In step S8, a display processing procedure by the display processing unit 14 is executed. In the display processing procedure, out of the latent image information 38, information corresponding to the latent image part 31 (hereinafter referred to as "latent image part image information 42") is superimposed on the latent image part 31, and the specific part image information 41 is superimposed on the latent image part 31. It is displayed on the display screen section 15 in step S9, superimposed on the specific image latent image section 32. A series of processes from steps S1 to S9 are executed in real time. In other words, for example, when a camera such as a mobile terminal is held up to the subject 30, the image information 37 is not recorded as a still image or a video and then processed. At the same time, steps S1 to S9 are processed, and the latent image information 38 that has been made visible appears on the display screen section 15, overlapping the latent image 36, so that the latent image 36 looks conspicuous. Therefore, for example, when operating with a mobile terminal or the like, it is easy to handle and it is easy to determine authenticity. In particular, since the latent image information 38 appears conspicuously in chromatic colors on the display screen section 15, it is clear and easy to determine authenticity.

In step S11, since the display processing unit 14 does not operate, the latent image information 38 that has become visible does not appear on the display screen unit 15. That is, only the image information 37 is displayed on the display screen section 15. Therefore, since it can be determined that the photographed object 30 in which the manifested latent image information 38 does not appear is a fake, it is easy to determine the authenticity.

As described above, in this embodiment, for example, the halftone dots and parallel lines printed on anti-counterfeit printed matter are read as image information 37, and the positional information of points such as dot codes is not analyzed. The specifications are simple.

Note that in other embodiments of the present invention, the latent image does not include the specific image latent image portion.
Other embodiments do not include the extraction processing section if filter processing is not required.
Other embodiments do not include an expansion/deflation processing section if expansion/deflation processing is not required.
Other embodiments do not include the manifestation processing section if the manifestation processing is not required.
In other embodiments, the determination unit makes the determination before step S6.
In another embodiment, the display processing unit displays only the latent image part image information on the latent image part, out of the latent image information, on the display screen part, and does not make the specific part image information visible on the display screen. .
Other embodiments include printing the area to be read on the subject.
In another embodiment, the specific image is not a specific image latent image portion, but is in a form that is visible in the same manner as printed characters. In this case, the specific image information stored in the storage unit is associated with the specific image, and the determining unit determines whether the specific image and the specific image information match. Image information based on a specific image serves as a starting point, and a display processing procedure is executed by the display processing section.
In another embodiment, print image information is extracted together with latent image information in an image processing procedure by an image processing unit, and print image information is converted into chromatic colors together with latent image information in coloring processing by a coloring processing unit. . In this case, the latent image information and the printed image information may be the same color, may be the same color but have different densities, or may be different colors.
In another embodiment, the specific part image information is detected by artificial intelligence in the determination procedure by the determination unit. A general machine learning algorithm such as a neural network is used to detect the specific part image information.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. The present invention can be modified in various ways without departing from the scope of the claims.

1 CPU
2 Storage section 3 ROM
4 RAM
5 HDD/SSD
6 Imaging section 7 Image processing section 8 Extraction processing section 9 Binarization processing section 10 Expansion/contraction processing section 11 Revealing processing section 12 Coloring processing section 13 Judgment section 14 Display processing section 15 Display screen section 20 Authenticity judgment device 30 Subject 31 Subtraction Image area 32 Specific image latent image area 33 Background 34 Area to be read 35 Printed characters 36 Latent image 37 Image information 38 Latent image information 39 Printed image information 40 Background image information 41 Specific area image information 42 Latent image area image information

Claims (7)

an imaging unit that reads a subject on which a read area including a latent image is printed in advance as image information;
an image processing unit that extracts latent image information, which is the image information of the latent image, from the image information and makes it visible;
a display processing unit that displays the manifested latent image information on a screen superimposed on the latent image simultaneously with the reading by the imaging unit;
The area to be read is
The latent image is composed of a flat mesh or parallel lines and can be copied by a copying machine;
a background that is composed of a flat mesh or parallel lines and whose reproduction by a copying machine is inferior to the latent image,
The lines of the latent image have a width of 0.05 to 0.35 mm, a pitch of 0.2 to 0.8 mm, or
The flat screen of the latent image has a diameter of 0.1 to 0.5 mm and a pitch of 0.2 to 0.8 mm.
An authentication device characterized by: a determination unit that determines whether or not a specific image included in the read area and specific image information stored in advance in association with the specific image match;
When the specific image matches the specific image information, the display processing unit operates;
The authenticity determination device according to claim 1, characterized in that: The latent image is
including a specific image latent image portion that is the specific image;
The authenticity determination device according to claim 2, characterized in that: The image processing section
comprising a coloring processing unit that converts the manifested latent image information into chromatic colors;
The authenticity determination device according to any one of claims 1 to 3, characterized in that: The image processing section
an extraction processing unit that extracts low frequency components from the image information;
a binarization processing unit that binarizes the image information;
an expansion/contraction processing unit that performs expansion/contraction processing on the binarized image information;
The authenticity determination device according to any one of claims 1 to 3, characterized in that: a printing procedure for printing a read area including a latent image on a subject;
an imaging procedure for reading the subject as image information;
an image processing procedure for extracting and manifesting latent image information, which is the image information of the latent image, from the image information;
a display processing procedure of displaying the manifested latent image information on a screen superimposed on the latent image at the same time as it is read by the imaging procedure;
The area to be read is
The latent image is composed of a flat mesh or parallel lines and can be copied by a copying machine;
a background that is composed of a flat mesh or parallel lines and whose reproduction by a copying machine is inferior to the latent image,
The lines of the latent image have a width of 0.05 to 0.35 mm, a pitch of 0.2 to 0.8 mm, or
The flat screen of the latent image has a diameter of 0.1 to 0.5 mm and a pitch of 0.2 to 0.8 mm.
Authenticity determination method characterized by the following. an imaging procedure for reading an object on which a reading area including a latent image is printed in advance as image information;
an image processing procedure for extracting and manifesting latent image information, which is the image information of the latent image, from the image information;
causing a computer to execute a display processing procedure for displaying the manifested latent image information on a screen, superimposing it on the latent image at the same time as it is read by the imaging procedure;
The area to be read is
The latent image is composed of a flat mesh or parallel lines and can be copied by a copying machine;
a background that is composed of a flat mesh or parallel lines and whose reproduction by a copying machine is inferior to the latent image,
The lines of the latent image have a width of 0.05 to 0.35 mm, a pitch of 0.2 to 0.8 mm, or
The flat screen of the latent image has a diameter of 0.1 to 0.5 mm and a pitch of 0.2 to 0.8 mm.
Authenticity determination program characterized by:

Images