Method and software for visualizing latent image

Abstract

To provide a method for easily visualizing a latent image without requiring a discrimination tool such as a parallel line filter and a lenticular lens.SOLUTION: By a terminal including at least a display unit, an image processing unit, and any one of a storage unit and an imaging unit, from image data of a latent image pattern including a plurality of latent image elements in which a latent image is visualized by being periodically sampled, A latent image visualization method for visualizing a latent image hidden in a latent image pattern includes a step of displaying image data of the latent image pattern captured by an imaging unit or image data of the latent image pattern stored in advance in a storage unit on a display unit, and a step of reducing the image data of the latent image pattern by an image processing unit, thereby visualizing the latent image on the display unit.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for easily visualizing a latent image using a terminal with a display, and software for such visualization, in a technology that allows a latent image to be viewed by superimposing a discriminator such as a line filter or lenticular lens on the image to be observed in security products that require prevention of counterfeiting and tampering of banknotes, stock certificates, bonds, and other securities, various certificates, important documents, and packaging for luxury goods. [Background technology]

[0002] Security products use a variety of technologies to provide anti-counterfeiting protection. In recent years, with the advancement of high-resolution color copiers and the computerization of color platemaking technology, the counterfeiting technologies used in security products have become increasingly diverse. Accordingly, the counterfeiting prevention measures for security products have also become more sophisticated. However, at the same time, the manufacturing costs of the counterfeiting prevention measures have risen, and in order to create an environment in which the counterfeiting protection can be verified, it has sometimes become necessary to install specialized equipment consisting of specialized machinery and tools, resulting in high costs for authenticating the products.

[0003] One useful method that enables authenticity determination at low cost is a technology that performs authenticity determination by overlaying a discriminator (2) on the base material (1) of a security product, as shown in Figure 1. In other words, by overlaying a discriminator on the base material (1) on which an invisible image (latent image) is applied, the invisible image (latent image) is made visible, and the main forms of this discriminator (2) are a transparent sheet printed with a parallel line screen (hereinafter referred to as a "parallel line filter"), a lenticular lens, or a lens array.

[0004] As one of the counterfeit prevention technologies that utilizes such a discriminator to reveal a latent image, the present applicant has filed a patent application for a latent image pattern revealing structure in which a discriminator is superimposed on a phase modulation pattern in which the design of the latent image pattern is revealed by the phase differences of some of the elements arranged in a line pattern, and the latent image can be visually recognized by observing the discriminator (see, for example, Patent Document 1). The technology described in Patent Document 1 improves the concealment of the design of the latent image pattern revealed by the phase differences of some of the elements arranged in a line pattern.

[0005] Another example of an anti-counterfeiting technology that uses a discriminator to reveal a latent image is a technology disclosed in which a latent image pattern is formed by forming multiple latent image elements, each of which is a compressed base image, at a fixed pitch, and the latent image becomes visible when a discriminator corresponding to the latent image pattern is placed over it (see, for example, Patent Document 2).

[0006] The applicant has also filed a patent application for a method for inspecting printed matter, which is capable of reading latent images by capturing an image of the latent image pattern on the printed matter to obtain image data, and then performing smoothing processing in one direction, edge extraction processing, and smoothing processing in the other direction on the obtained image data to display the image (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7224588 [Patent Document 2] Patent No. 4427796 [Patent Document 3] Patent No. 6860151 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the anti-counterfeiting techniques used in the techniques described in Patent Documents 1 and 2 require discriminating tools such as lenticular lenses and line filters, which are not carried by everyone, and therefore, it is not possible for everyone to easily determine whether a document is genuine or not.

[0009] Furthermore, according to the technology described in Patent Document 3, it is possible to visualize a latent image by image processing even without carrying a discrimination tool. However, since it is necessary to perform image processing corresponding to the latent image pattern added as an anti-counterfeiting technology, there are problems in that the anti-counterfeiting technology that can be visualized is limited and complex image processing is required.

[0010] Therefore, an object of the present invention is to provide a method for easily visualizing a latent image using a terminal having a display. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides a latent image visualization method for visualizing a latent image concealed in a latent image pattern from image data of the latent image pattern having a plurality of latent image elements that are periodically sampled to visualize the latent image, by a terminal having at least a display unit, an image processing unit, and either a memory unit or an imaging unit, characterized in that the latent image is visualized by the steps of: displaying image data of the latent image pattern captured by the imaging unit or stored in advance in the memory unit on the display unit; and reducing the image data of the latent image pattern by the image processing unit.

[0012] The present invention also provides a latent image visualization method, further comprising the step of detecting, by an image processing unit, that the latent image has been visualized and terminating the reduction process.

[0013] The present invention also provides a method for determining authenticity of a latent image pattern by comparing a latent image visualized using the above-mentioned latent image visualization method with authenticity determination data previously stored in a memory unit.

[0014] The present invention also provides software for visualizing a latent image, characterized in that it causes a computer provided in a terminal to execute the above-mentioned latent image visualizing method.

[0015] The present invention also provides software for authenticity determination, characterized in that it causes a computer provided in a terminal to execute the above authenticity determination method. [Effects of the Invention]

[0016] The latent image visualization method and visualization software of the present invention eliminate the need for the discriminator or complex image processing that was previously required to visualize latent images, and allows latent images to be easily visualized using a terminal with a display that everyone carries with them. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a conventional method for developing a latent image. [Figure 2] FIG. 10 is a diagram showing a conventional latent image pattern and a configuration in which a latent image is revealed by a discrimination tool. [Figure 3] FIG. 10 is a diagram showing a state in which a latent image is visualized by the visualization method of the present invention. [Figure 4] FIG. 2 is a diagram illustrating a hardware configuration of a terminal according to the present invention. [Figure 5] FIG. 1 is a diagram showing an example of an arrangement of subpixels in a display. [Figure 6] FIG. 3 is a flowchart illustrating a method for visualizing a latent image according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing the configuration of a first latent image pattern. [Figure 8] FIG. 10 is a diagram showing the relationship between image data of a first latent image pattern and sub-pixels. [Figure 9] FIG. 10 is a diagram showing an example of the arrangement relationship with sub-pixels when image data of the first latent image pattern is reduced. [Figure 10] FIG. 10 is a diagram showing the light emission state of the display when image data of the first latent image pattern is reduced. [Figure 11] FIG. 10 is a diagram showing the configuration of sub-pixels in a state where a latent image is visualized in a first latent image pattern. [Figure 12] FIG. 10 is a diagram showing a state in which the latent image of the first latent image pattern is actually visualized. [Figure 13] FIG. 10 is a diagram showing the configuration of a second latent image pattern. [Figure 14] FIG. 10 is a diagram showing the relationship between image data of a second latent image pattern and sub-pixels. [Figure 15] FIG. 10 is a diagram showing an example of the arrangement relationship with sub-pixels when image data of a second latent image pattern is reduced. [Figure 16] FIG. 10 is a diagram showing the light emission state of the display when image data of the second latent image pattern is reduced. [Figure 17] FIG. 10 is a diagram showing the configuration of sub-pixels in a state where the latent image is visualized in the second latent image pattern. [Figure 18] FIG. 10 is a diagram showing a state in which the latent image is visualized in color by reducing the image data in another configuration of the second latent image pattern. [Figure 19] FIG. 10 is a diagram showing a third latent image pattern and its base image. [Figure 20] FIG. 10 is a diagram showing the relationship between image data of a third latent image pattern and sub-pixels. [Figure 21] FIG. 10 is a diagram showing an example of the arrangement relationship with sub-pixels when image data of a third latent image pattern is reduced. [Figure 22] FIG. 10 is a diagram showing the configuration of sub-pixels in a state where the latent image is visualized in the third latent image pattern. [Figure 23] FIG. 10 is a diagram showing a state in which the latent image of the third latent image pattern is actually visualized. [Figure 24]FIG. 10 is a diagram showing image data of a fourth latent image pattern and an original image, and a state in which the latent image is visualized. [Figure 25] FIG. 10 is a diagram showing a fifth latent image pattern and its base image. [Figure 26] FIG. 10 is a diagram showing details of a fifth latent image pattern. [Figure 27] 10A and 10B are diagrams illustrating a fifth method for forming a latent image pattern. [Figure 28] FIG. 10 is a diagram showing image data of a fifth latent image pattern and a state in which the latent image is visualized. [Figure 29] FIG. 10 is a flowchart illustrating a method for visualizing a latent image according to the second embodiment. [Figure 30] FIG. 10 is a diagram illustrating an example of correction before image processing. [Figure 31] FIG. 10 is a diagram showing image data of a corrected latent image pattern. [Figure 32] FIG. 11 is a flowchart illustrating a method for visualizing a latent image according to the third embodiment. [Figure 33] 10A and 10B are diagrams showing an example of displaying imaging assist lines on a display during imaging. [Figure 34] FIG. 10 is a diagram showing an example of an announcement displayed on a display during imaging to ensure optimal imaging conditions. [Figure 35] FIG. 10 is a diagram showing an example of automatically capturing an image when optimal imaging conditions are met during imaging. [Figure 36] FIG. 13 is a flowchart illustrating a method for determining the authenticity of a latent image according to a fourth embodiment. [Figure 37] 10A and 10B are diagrams illustrating an example of a method for adjusting the reduction ratio of image data displayed on a display by operating an input unit. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following description will discuss embodiments of the present invention with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, and various other embodiments are also encompassed within the scope of the technical concept set forth in the claims.

[0019] Fig. 2 is a diagram illustrating a conventional visualization method and its principle, in which a latent image (3) is visualized by periodically sampling a plurality of latent image elements constituting the latent image pattern (10) when a discriminator (2) is placed over the latent image pattern (10). Fig. 2(b) is a diagram showing an example of the configuration of the latent image pattern (10), in which colored elements (11) having an element width (W1) and a predetermined length in a first direction (S1) are arranged at a constant pitch (P) in a second direction (S2), and further, as shown in the enlarged view of Fig. 2(b), are divided into a latent image portion (11A) and a background portion (11B) by differences in the phase of some of them. In the following explanation, of the colored elements (11) that make up the latent image pattern (10), the colored elements (11) in the latent image portion (11A) will be referred to as "first latent image elements (12A1)," and the colored elements (11) in the background portion (11B) will be referred to as "second latent image elements (12A2)." The first latent image elements (12A1) and the second latent image elements (12A2) have the same element width (W1), and the first latent image elements (12A1) and the second latent image elements (12A2) are arranged at the same pitch (P). In the present invention, "the phases of the elements are different" means that the first latent image elements (12A1) and the second latent image elements (12A2) are arranged so as to be shifted from each other in a second direction (S2) that is perpendicular to the first direction (S1). Furthermore, the latent image pattern (10) shown in FIG. 2 shows an example in which the first latent image elements (12A1) are arranged with a shift in the second direction (S2), but they may also be arranged with a shift in the direction opposite to the second direction (S2).

[0020] Figure 2(c) shows a line filter as an example of the discriminator (2), in which multiple filter elements (14) are arranged with the same element width (W1) and the same pitch (P) as the colored elements (11) that make up the latent image pattern (10). By overlaying the discriminator (2) shown in Figure 2(c) on the latent image pattern (10) shown in Figure 2(b), the latent image (3) is visualized as shown in Figure 2(a). Depending on the arrangement of the discriminator (2) and the first latent image pattern (10), a negative (white) latent image (3) or a positive (black) latent image (3) is visualized when the first latent image element (12A1) is sampled or when the second latent image element (12A2) is sampled.

[0021] One mode of visualizing the latent image (3) in the present invention will be described with reference to FIG. 3. FIG. 3(a) shows a state in which image data of the latent pattern (10) is displayed on the display (4a) of the terminal (4). For example, image data of the latent pattern (10) captured by the imaging unit (105) described below is displayed. At this stage, the latent image (3) is not visible. FIG. 3(b) shows a state in which the image data shown in FIG. 3(a) has been reduced, and the character "1" representing the latent image (3) is visualized. In other words, the present invention does not require the preparation of a special discriminator (2) that was previously required, nor does it require complex image processing to visualize the latent image (3). The principle by which the latent image (3) is visualized will be described in detail later; however, the latent image (3) is visualized simply by reducing the image data of the latent pattern (10) displayed on the display (4a) of the terminal (4).

[0022] FIG. 4 shows a block diagram illustrating the hardware configuration of the terminal (4) used in the present invention. The terminal (4) referred to here is not particularly limited and may be any device with a display, such as a mobile phone (including a smartphone), a tablet device, or a personal computer. The terminal (4) comprises at least a display unit (102), an image processing unit (103), and either a memory unit (101) or an imaging unit (105). It may also have an input unit (104) and an external connection unit (106).

[0023] The storage unit (101) includes a ROM, RAM, hard disk, etc., and stores image data of the latent image pattern used in the present invention and programs for enlarging, reducing, correcting, etc. the image data. It may also store a base image that serves as a reference for the latent image. If the terminal (4) has an authenticity determination function, it may also store data necessary for authenticity determination.

[0024] The image data of the latent image pattern (10) stored in the storage unit (101) is not limited to being stored in advance on a hard disk or the like, and if the terminal (4) has an imaging unit (105) described later, the image data of the captured latent image pattern (10) may be stored. Also, if the terminal (4) has an external connection unit (106) described later, an external terminal, cloud, etc. may be used as the storage unit (101).

[0025] The display unit (102) is a display that displays image data of the latent image pattern (10), and if the display unit (102) has a touch panel function, it can also include the function of the input unit (104) described below.

[0026] The image processing unit (103) performs enlargement / reduction processing and correction of the image data, and determines authenticity based on the visualized latent image.

[0027] The terminal 4 may also have an input unit 104. The input unit 104 is configured with a keyboard, a mouse, and the like, and receives user operations.

[0028] The terminal (4) may also have an imaging unit (105). The imaging unit (105) is a camera with an imaging function, which can capture an image of the latent image pattern (10) and import it as image data.

[0029] The external connection unit (106) is a network interface or various connection interfaces with external devices.

[0030] Figure 5 is an enlarged view of the display (4a) of the terminal (4), showing an example of a subpixel arrangement. A subpixel is a subdivision of the tiny colored dots (pixels) that make up the display (4a), and consists of only one primary color. Typically, a group of three subpixels (red, green, and blue) functions as one pixel.

[0031] As shown in Figures 5(a) and 5(b), the subpixels are arranged in a regular pattern with red subpixels R (5a), green subpixels G (5b), and blue subpixels B (5c), and the colors and shades of the image displayed on the display (4a) are reproduced by adjusting the RGB values ​​of each subpixel (5a, 5b, 5c) between 0 and 255. For example, an RGB value of (0, 0, 0) results in black, an RGB value of (255, 0, 0) results in red, an RGB value of (128, 128, 128) results in gray, and an RGB value of (255, 255, 255) results in white.

[0032] In the following explanation, when referring to subpixels in general rather than individual subpixels (5a, 5b, 5c), the term "subpixel (5)" will be used. The arrangement method in Fig. 5(a) is called "Stripe RGB," and the arrangement method in Fig. 5(b) is called "Diamond PenTile RGBG," and there are several other types of arrangement methods, but the effects of the present invention can be obtained as long as the subpixels (5a, 5b, 5c) are arranged regularly, so the following explanation will use an example using "Stripe RGB" in Fig. 5(a).

[0033] (First embodiment) FIG. 6 is a diagram showing a flowchart of a method for visualizing a latent image (3) from image data of a latent pattern (10) in the first embodiment. The flowchart in FIG. 6 shows a method in which a user reduces image data and visualizes a latent image (3) using a terminal (4) having at least a storage unit (101), a display unit (102), and an image processing unit (103). In addition, the principle by which a latent image (3) is visualized from various latent patterns (10) (hereinafter referred to as the first to fifth latent patterns) according to the first embodiment will be explained in order. First, a method for visualizing a latent image (3) in a first latent pattern (10) will be explained using FIGS. 7 to 12.

[0034] (First latent image pattern) FIG. 7 is a diagram showing the configuration of the first latent image pattern (10), which is the same as the latent image pattern (10) described in FIG. 2(b), so a detailed description of the configuration will be omitted. Image data of the first latent image pattern (10) is acquired (STEP 1). One example of acquiring image data is to read data stored in the memory unit (101) of the terminal (4). Next, the image data of the first latent image pattern (10) shown in FIG. 7 is displayed on the display (4a), which is the display unit (102) of the terminal (4) (STEP 2).

[0035] Figure 8(a) is an enlarged view of a portion of the first latent image pattern (10) shown in Figure 7, and Figure 8(b) shows the light emission state of the subpixels (5) when the first latent image element (12A1) and the second latent image element (12A2) of the first latent image pattern (10) shown in Figure 8(a) are displayed on the display (4a). Note that the first latent image element (12A1) and the second latent image element (12A2) shown in Figure 8(a) are illustrated with different patterns to distinguish them, but in reality they are displayed with the same color. In the first latent image pattern (10), an example will be described in which the first latent image element (12A1) and the second latent image element (12A2) are both black.

[0036] As shown in FIG. 8(b), the subpixels (5) corresponding to the first latent image element (12A1) and the second latent image element (12A2) are displayed as black subpixels Bk (5d), so that the RGB values ​​are 0 and the image is perceived as black. In addition, in areas where the first latent image element (12A1) and the second latent image element (12A2) are not present, the RGB values ​​of the subpixels R (5a), G (5b), and B (5c) are 255 and the image is perceived as white according to the principle of the three primary colors of light. In the image data shown in FIG. 8(b), the size of each element of the first latent image pattern (10) is equal to or larger than one subpixel, so that the first latent image pattern (10) is appropriately displayed as image data as shown in FIG. 8(b).

[0037] Next, FIG. 9 shows an example of reducing the image data shown in FIG. 8(a), in which the image data of the first latent image pattern (10) displayed on the display (4a) is reduced (STEP 3). The reduction process is performed by the image processing unit (103). The reduction method is not particularly limited as long as it can reduce the image data, such as a pinch operation manually input by the user or automatic control by image processing. In this embodiment, an example of a pinch operation by the user will be described. Note that, like FIG. 8, FIG. 9 illustrates an enlarged portion of the image data of the first latent image pattern (10), but in reality, the image data of the entire first latent image pattern (10) shown in FIG. 7 is reduced.

[0038] At a predetermined reduction ratio, when the first latent image element (12A1) is located at the center of one subpixel (5) in the image data of the first latent image pattern (10), as shown in the enlarged view (K1) of the latent image portion (11A), the second latent image element (12A2) is displayed so as to straddle two subpixels (5) above and below, as shown in the enlarged view (K2) of the background portion (11B). In this case, pixel interpolation causes the subpixel (5) where the first latent image element (12A1) is located to have an RGB value of 0, becoming a black subpixel Bk (5d), and the subpixel (5) where the second latent image element (12A2) is located to have an RGB value of 255, appearing white. Pixel interpolation is an image process that calculates the RGB values ​​of pixels to be replaced when an image is enlarged or reduced, and one example is a process called nearest neighbor interpolation. The positional relationship between the first latent image element (12A1), the second latent image element (12A2), and the sub-pixel (5) shown here varies depending on the reduction ratio.

[0039] Figure 10(a) shows image data reduced at the same reduction ratio as Figure 9, and Figure 10(b) shows the actual light emission state of the subpixels (5) when the image data shown in Figure 10(a) is displayed on the display (4a). As mentioned above, only the subpixel (5) where the first latent image element (12A1) is located is a black subpixel Bk (5d).

[0040] FIG. 11 is a reduced view of the entire image data of the first latent image pattern (10), and only the location of the first latent image element (12A1) in the first latent image pattern (10) is displayed as a black subpixel Bk (5d), thereby making the latent image (3) visible (STEP 4).

[0041] Figure 12 shows the state in which the image data of the first latent image pattern (10) actually displayed on the display (4a) is reduced to visualize the latent image (3), with Figure 12(a) showing the image data before reduction. Figures 12(b) and 12(c) show the actually visualized latent image (3), with Figure 12(b) showing only the second latent image element (12A2) displayed in the black subpixel Bk (5d) and the latent image (3) reproduced as a negative image (white) depending on the reduction ratio, and Figure 12(c) showing only the first latent image element (12A1) displayed in the black subpixel Bk (5d) and the latent image (3) reproduced as a positive image (black). In this way, the state of the visualized latent image (3) changes depending on the reduction ratio. Furthermore, when the latent image (3) is reduced at a reduction ratio that makes it visible, only the first latent image element (12A1) is reproduced in positive (black) or negative (white) as shown in Figures 12(b) and 12(c), but when the reduction ratio is not the specified ratio, the first latent image element (12A1) and the second latent image element (12A2) are reproduced in a mixed state of positive (black) and negative (white), as shown in Figure 12(d).

[0042] An example of the reduction ratio will be described with reference to FIG. 12. First, the first latent image pattern (10) shown in FIG. 12(a) is displayed on a liquid crystal display. The LCD-AD192SEDSW (manufactured by I-O DATA Corporation) was used as the liquid crystal display. Next, the first latent image pattern (10) is cut out from the image data acquired by the memory unit (101) or the imaging unit (105) using a screenshot tool (e.g., the Snipping Tool), which is a standard function of a personal computer, and displayed in the Snipping Tool with a width (L) of 41 mm, a height (H) of 52.5 mm, and an element width (W1) of the colored elements (11) of 1 mm. When the image data of the first latent image pattern (10) under the above-mentioned conditions was reduced to 17.1%, a positive (black) latent image (3) was visualized as shown in FIG. 12(c). The reduction ratio for visualizing the latent image (3) in the present invention is not limited to the above value, but may vary depending on the configuration of the latent image pattern (10), the configuration of the display (4a), the imaging conditions, etc.

[0043] (Second latent image pattern) The second latent image pattern (10) will be described using Figures 13 to 18. Note that the visualization method for the latent images in the second to fifth latent image patterns is the same as that for the first latent image pattern, so the explanation using the flowchart shown in Figure 6 as the first embodiment will be omitted, and only the principle of visualizing the latent image will be described. Figure 13 shows the second latent image pattern (10) having the configuration described in Japanese Patent No. 6808188, in which the latent image (3) is visually recognized in color.

[0044] The configuration of the second latent image pattern (10) will be described using Figure 13. The second latent image pattern (10) has elements whose colors differ depending on the design of the latent image portion (11A). Specifically, as shown in the enlarged view of Figure 13(a), the portion corresponding to the number "1" is made up of a first latent image element (12A1) and a second latent image element (12A2) that are complementary colors adjacent to each other, and the portion corresponding to the background of the number "1" is made up of an achromatic third latent image element (12A3). Note that the third latent image element (12A3) is not limited to a single achromatic color; the effects of the present invention can also be achieved by a configuration in which two complementary colors are adjacent to each other.

[0045] With this configuration, the first latent image element (12A1) and the second latent image element (12A2) are visible to the naked eye in a mixed color state, so the second latent image pattern (10) appears to have achromatic elements arranged at regular intervals. Furthermore, when a discrimination tool (2) is placed over the second latent image pattern (10) shown in Figure 13(a), the latent image (3) is visualized by periodically sampling the multiple latent image elements that make up the second latent image pattern (10). Depending on the arrangement of the discriminator (2) and the second latent image pattern (10), the number "1" is perceived in the color of the first latent image element (12A1), the color of the second latent image element (12A2), or the color of the base material between the first latent image element (12A1) and the second latent image element (12A2), depending on whether the first latent image element (12A1), the second latent image element (12A2), or the third latent image element (12A3) is sampled, and the background of the number "1" is perceived as an achromatic color. This achromatic color is a color without saturation, such as gray or black.

[0046] In the latent image pattern (10) described in Japanese Patent No. 6808188, the first latent image element (12A1) shown in FIG. 13(a) may be composed of one color from a combination of complementary colors, and the second latent image element (12A2) may be composed of the remaining color from the combination of complementary colors. Alternatively, as shown in the enlarged view of FIG. 13(b), the first latent image element (12A1) may have partially different colors. In this case, the color of the adjacent second latent image element (12A2) may be different for each portion of the first latent image element (12A1) composed of different colors. In the enlarged view of FIG. 13(b), the latent image elements (12A1, 12A2) composed of different colors are shown with different patterns, but in reality, complementary color elements, such as "blue and yellow" or "green and magenta," are adjacent depending on the design of the latent image pattern. In the second latent image pattern (10) shown in Figure 13(b), the overlapping arrangement of the discriminators (2) allows the color of the first latent image element (12A1) or the second latent image element (12A2) to be visible as the latent image (3), and a colorful latent image (3) can be viewed.

[0047] Fig. 14(a) is an enlarged view of the second latent image pattern (10) shown in Fig. 13(a), and Fig. 14(b) shows the light emission state of the subpixels (5) when the first latent image element (12A1), the second latent image element (12A2), and the third latent image element (12A3) shown in Fig. 14(a) are displayed on the display (4a). An example of the second latent image pattern will be described in which the first latent image element (12A1) is red, the second latent image element (12A2) is cyan, and the third latent image element (12A3) is gray.

[0048] As shown in Figure 14(b), the area corresponding to the third latent image element (12A3) is displayed in gray, and is therefore designated as subpixel Gray (5e). In reality, the RGB values ​​of subpixel R (5a), subpixel G (5b), and subpixel B (5c) are each reduced equally, resulting in a perceived gray color. However, for ease of explanation, all subpixels (5) are designated as subpixel Gray (5e). As an example, the case where the RGB values ​​of subpixel R (5a), subpixel G (5b), and subpixel B (5c) are each 128 will be described.

[0049] Next, the subpixel (5) corresponding to the first latent image element (12A1) is displayed in red, so the RGB value of subpixel R (5a) is 255 and the RGB values ​​of subpixel G (5b) and subpixel B (5c) are 0, resulting in a red component in the area corresponding to the first latent image element (12A1). The subpixel (5) corresponding to the second latent image element (12A2) is displayed in cyan, so the RGB value of subpixel R (5a) is 0 and the RGB values ​​of subpixel G (5b) and subpixel B (5c) are 255, resulting in a cyan component in the area corresponding to the second latent image element (12A2) according to the principle of the three primary colors of light. In the image data shown in FIG. 14(b), the size of each element of the second latent image pattern (10) is equal to or larger than one subpixel, so the second latent image pattern (10) is appropriately displayed as image data, as shown in FIG. 14(b).

[0050] Next, the image data of the second latent image pattern (10) displayed on the display (4a) is reduced as shown in Fig. 15. The reduction operation is the same as in the first embodiment, so a description thereof will be omitted.

[0051] As shown in the enlarged view (K1) of the latent image portion (11A) of the image data of the second latent image pattern (10), when the first latent image element (12A1) is located at the center of one subpixel (5), the second latent image element (12A2) is formed out of phase and is therefore displayed as being positioned across two subpixels (5). In this case, through pixel interpolation, the subpixel R (5a) where the first latent image element (12A1) is located has an RGB value of 255, the remaining subpixels (5b, 5c) have RGB values ​​of 0 and become a black subpixel Bk (5d), and the subpixel (5) where the third latent image element (12A3) is located all have an RGB value of 128 and become a gray subpixel (5e).

[0052] Next, Figure 16(a) is the same as Figure 15, and Figure 16(b) is a diagram showing the actual light emission state of the subpixels (5) when the image data shown in Figure 16(a) is displayed on the display (4a). As mentioned above, of the subpixels (5) where the first latent image element (12A1) is located, only the subpixel R (5a) has an RGB value of 255, and the remaining subpixels (5b, 5c) are black subpixels Bk (5d). Furthermore, the subpixels (5) where the third latent image element (12A3) is located all have an RGB value of 128, making them gray subpixels Gray (5e).

[0053] Fig. 17(a) is a diagram showing the entire image data of the second latent image pattern (10), and in the area corresponding to the first latent image element (12A1) in the second latent image pattern (10), only the sub-pixel R (5a) emits light, the second latent image element (12A2) is not reflected in the sub-pixel (5), and the area corresponding to the third latent image element (12A3) is displayed in gray, thereby visualizing a red latent image (13) as shown in Fig. 17(b). Furthermore, by changing conditions such as the configuration of the second latent image pattern (10) and the reduction ratio of the image data, a cyan latent image (13) consisting of the second latent image element (12A2) is visualized.

[0054] Figure 18 shows a latent image pattern (10) for visualizing a latent image (13) with excellent gradation expression by using an element configuration such as that shown in Figure 13(b), and a latent image (13) visualized by actually reducing the image data of the latent image pattern (10). Figure 18(a) shows the image data of the latent image pattern (10) before reduction, and Figure 18(b) shows the actually visualized latent image (13). The present invention can also visualize a latent image (13) such as that shown in Figure 18(b).

[0055] (Third latent image pattern) The third latent image pattern (20) will be described with reference to Figures 19 to 23. The third latent image pattern (20) is formed by compressing the original image (21) shown in Figure 19(a) in the first direction (S1) to form a plurality of latent image elements (22) at a constant pitch in the first direction (S1), and the third latent image pattern (20) is shown in Figure 19(b). As an example of the original image (21), an example using a "circle" shown in Figure 19(a) will be described. In a conventional method for visualizing a latent image, when a discriminator (2) is placed on the third latent image pattern (20) shown in Figure 19(b), a portion of the plurality of latent image elements (22) is sampled, causing a moire magnification phenomenon, and the original image (21) is visualized as a latent image.

[0056] Figure 20(a) shows the image data of the original image (21) shown in Figure 19(a), and Figure 20(b) shows the light emission state of the sub-pixels (5) when the original image (21) shown in Figure 20(a) is displayed on the display (4a). In Figure 20(b), the area corresponding to the original image (21) is illustrated surrounded by a dotted circle for ease of explanation. In the third latent image pattern, an example will be described in which the "circle" portion of the original image (21) is configured in yellow and its background portion is configured in white.

[0057] As shown in Figure 20(b), the subpixels (5) in the area corresponding to the original image (21) have RGB values ​​of 255 for subpixel R (5a) and subpixel G (5b), and RGB value of 0 for subpixel B (5c), and are perceived as yellow according to the principle of the three primary colors of light. Therefore, the area corresponding to the original image (21) is reproduced in yellow, and a yellow circle is perceived. Note that the background area is perceived as white because all RGB values ​​of subpixel R (5a), subpixel G (5b), and subpixel B (5c) are 255.

[0058] Next, Figure 21(a) shows image data of a third latent image pattern (20) obtained by compressing the image data of the original image (21) shown in Figure 19(a) in the first direction (S1), arranging eight latent image elements (22) in the first direction (S1), and reducing the image data at a predetermined reduction rate. Figure 21(b) shows the light emission state of the subpixels (5) when the image data of the third latent image pattern (20) shown in Figure 21(a) is displayed on the display (4a). In Figure 21(b), the area corresponding to the image data of the third latent image pattern (20) is also illustrated surrounded by a dotted ellipse for ease of understanding.

[0059] In Figure 21(b), in the sub-pixels (5) corresponding to the latent image elements (22) constituting the image data of the third latent image pattern (20), the RGB values ​​of sub-pixel R (5a) and sub-pixel G (5b) are 255, and the RGB value of sub-pixel B (5c) is 0. However, since the individual latent image elements (22) constituting the third latent image pattern (20) shown in Figure 21(a) have been reduced to a size that cannot be reproduced with the size of the sub-pixels (5) shown in Figure 21(b), the individual latent image elements (22) cannot be displayed properly. In this case, when observing the portion where the RGB value of sub-pixel B (5c) is 0, it is found to have a shape close to the circle of the original image (21).

[0060] Figure 22 is a schematic diagram showing how a display (4a) consisting of the subpixels (5) shown in Figure 21(b) appears to the naked eye, and the areas where the RGB values ​​of the subpixels R (5a) and G (5b) are 255 and the RGB value of the subpixel B (5c) is 0 appear yellow, and therefore a yellow circular latent image (23) is visible as shown in Figure 22. Note that by adjusting the reduction ratio of the image data of the third latent pattern (20), the number and shape of the latent images (23) change and become visible.

[0061] Fig. 23 shows the state in which the image data of the third latent image pattern (20) actually displayed on the display (4a) is reduced to visualize the latent image (23), and Fig. 23(a) is the image data before reduction. Fig. 23(b) is a diagram showing the actually visualized latent image (23), and when the third latent image pattern (20) consisting of the multiple latent image elements (22) shown in Fig. 23(a) is actually reduced, one latent image (23) is visualized. The base image (21) for forming the third latent image pattern (20) has been described as an example of a "circle" for ease of explanation, but is not limited to this and may be a letter, symbol, or other design.

[0062] (Fourth latent image pattern) FIG. 24 shows the base image (31), fourth latent image pattern (30), and latent image (33) in the fourth latent image pattern (30). Here, an example will be described in which the letter "A" is used as the base image (31). In the third latent image pattern (20), latent image elements (22) formed by compressing the base image (21) only in the first direction (S1) are arranged in the first direction (S1). However, in the fourth latent image pattern (30), latent image elements (32) formed by compressing the base image (31) shown in FIG. 24(a) in both the first direction (S1) and the second direction (S2) are arranged in a grid pattern in both the first direction (S1) and the second direction (S2). Note that the fourth latent image pattern (30) is actually compressed to a size that is difficult to visually recognize, but for ease of explanation, it is illustrated larger than its actual size. The principle by which the latent image (33) in the fourth latent image pattern is visualized is the same as that in the third latent image pattern, and therefore will not be described here.

[0063] By reducing the fourth latent image pattern (30) shown in Fig. 24(b) at a predetermined reduction rate, the latent image (33) is visualized as shown in Fig. 24(c). Note that, when the reduction rate of the image data is changed, the size and number of "A" in the latent image (33) change and are visually recognized.

[0064] (5th latent image pattern) The fifth latent image pattern (40) is formed by dividing and compressing the base image (41) to form a plurality of latent image elements at a fixed pitch in the first direction (S1), and will be described using Figures 25 to 28. Here, an example will be described in which the character "forest" shown in Figure 25(b) is used as the base image (41).

[0065] The fifth latent image pattern (40) in Figure 25(a) is composed of a plurality of latent image elements (42-1, 42-2, ..., 42-n (n is a natural number greater than or equal to 2)) formed based on the character "forest" in the base image (41), which are regularly arranged in the first direction (S1) with a second element width (W2) shown in the enlarged view and a constant pitch (P). In the fifth latent image pattern (40), when referring to latent image elements in general rather than individual latent image elements (42-1, 42-2, ..., 42-n), the term will be described as latent image element (42). Furthermore, if the second element width (W2) of the latent image element (42) is formed beyond a certain pitch (P), an area will be created where the latent image element (42) and the adjacent latent image element (42) overlap, and the latent image (43) that appears may appear in a state where multiple elements are overlapped. Therefore, the second element width (W2) of the latent image element (42) needs to be designed to be equal to or less than the certain pitch (P).

[0066] The specific configuration of the fifth latent image pattern (40) will be described. The fifth latent image pattern (40) is a pseudo-reproduction, using image processing software, of an image observed through a vertical-slit lenticular lens in which kamaboko lenses are arranged continuously at a fixed pitch (P) overlaid on the character "forest" (mori), which is the base image (41). The fifth latent image pattern (40) is composed of multiple latent image elements (42-1, 42-2, ..., 42-n), and each latent image element (42-1, 42-2, ..., 42-n) is formed by compressing a portion of the character "forest" (mori), which is the base image (41), to the left and right by a specific percentage. In this way, the latent image elements (42-1, 42-2, ..., 42-n) in the fifth latent image pattern are formed not by a composite of discontinuous images but by continuous images. This is an essential condition for realizing smooth, moving visual effects and natural three-dimensional visual effects.

[0067] The latent image elements (42-1, 42-2, ..., 42-n) that make up the fifth latent image pattern (40), when taken from the left side of Figure 25(a) as latent image element (42-1), latent image element (42-2), ..., latent image element (42-n), are arranged with their phases shifted in the first direction (S1) by a fixed pitch (P). The second element width (W2) of the latent image elements (42-1, 42-2, ..., 42-n) is configured to be a width that does not exceed the fixed pitch (P), so the latent image elements (42) do not overlap each other.

[0068] 26 shows the configuration of the latent image elements (42-1, 42-2, ..., 42-n) forming the fifth latent image pattern (40). Of the multiple latent image elements (42-1, 42-2, ..., 42-n), the latent image element (42-1) located on the far left side of the drawing, the latent image element (42-16) located approximately in the center of the drawing, and the latent image element (42-28) located on the right side of the drawing will be extracted and explained. Although not shown in the figure, between the latent image element (42-1) and the latent image element (42-16), the latent image elements (42-2) to (42-15) are arranged at a constant pitch (P), and similarly, between the latent image element (42-16) and the latent image element (42-28), the latent image elements (42-17) to (42-27) are arranged at a constant pitch (P). The latent image elements (42-1, 42-16, 42-28) are formed by dividing the original image (41) by applying frames (44-1, 44-16, 44-28) of a predetermined size to the character "forest" in the original image (41), extracting the divided original image (41) as respective intra-frame images (45-1, 45-16, 45-28), and compressing these intra-frame images (45-1, 45-16, 45-28) to the second element width (W2).

[0069] The height of the frame fitted to the original image (41) only needs to be equal to or greater than the height of the original image (41), and the width (W3) of the frame shown in Fig. 26 needs to be equal to or less than the width of the original image (41). Therefore, the latent image element (42-1) located at the left end of the fifth latent image pattern (40) includes only the image of the left end portion of the original image (41), the latent image element (42-16) located approximately in the center of the fifth latent image pattern (40) includes only the image of the central portion of the original image (41), and the latent image element (42-28) located to the right of the fifth latent image pattern (40) includes only the image of the right portion of the original image (41).

[0070] An example of a specific procedure for creating the fifth latent image pattern (40) will be described using Figure 27. First, in step 1, the position of the leftmost frame (44-1) indicated by the solid line in the drawing is determined, which serves as the reference for all frame positions. The position of the leftmost frame (44-1) serving as the reference is the position where the right side of the frame (44-1) slightly overlaps the left edge of the original image (41). Here, "slightly overlapping position" refers to a position where the frame (44-1) and the original image (41) overlap even slightly, excluding positions where there is no overlap at all. The original image (41) contained in this frame (44-1) is defined as an intra-frame image (45-1), and this intra-frame image (45-1) is compressed to the second element width (W2), forming and arranging the latent image element (42-1).

[0071] Next, in step 2, the position of the frame (44-2) shown by the solid line is determined by shifting it a fixed pitch (P) to the right from the position of the leftmost frame (44-1) shown by the dotted line in the drawing. The original image (41) contained in the frame (44-2) is set as the intra-frame image (45-2), and similarly compressed to the second element width (W2) to create a latent image element (42-2), which is then positioned to the right of the latent image element (42-1) at a fixed pitch (P).

[0072] Next, in step 3, the position of frame (44-3) shown by solid lines is determined by shifting it a fixed pitch (P) to the right from the position of frame (44-2) shown by dotted lines. The original image (41) contained in frame (44-3) is set as the in-frame image (45-3), and similarly compressed to the second element width (W2) to create latent image element (42-3), which is then positioned a fixed pitch (P) to the right of latent image element (42-2). This procedure is repeated up to step n, and creation of latent image element (42) is completed when a position is reached where the original image (41) is no longer contained in the frame. In other words, the same procedure is repeated up to frame (44-n), and finally latent image element (42-n) is positioned to complete the fifth latent image pattern (40). The in-frame image (45-2) contains a portion of the adjacent in-frame image (45-1), and the in-frame image (45-3) contains a portion of the adjacent in-frame image (45-2). In this way, adjacent in-frame images each contain a portion of the overlapping base image (41). This fifth latent image pattern (40) can be created using commercially available image processing software. Note that in the above creation procedure, the left edge of the base image (41) was used as the reference point for the position of the reference frame, but this is not limited to this, and there is no problem with creating it using the center or right edge of the base image (41) as the reference point.

[0073] In this way, the latent image elements (42) in the fifth latent image pattern (40) are elements of different shapes obtained by compressing the image within the frame divided based on the base image (41) at a predetermined reduction ratio in the horizontal direction, vertical direction, or both directions, and each latent image element (42) is compressed at the same reduction ratio.

[0074] Fig. 28(a) shows the fifth latent image pattern (40) explained using Fig. 25 to Fig. 27, and when the image data of the fifth latent image pattern (40) shown in Fig. 28(a) is reduced at a predetermined reduction rate, the character "forest" is visualized as a latent image (43) as shown in Fig. 28(b). The principle by which the latent image (43) is visualized in the fifth latent image pattern is the same as that in the third latent image pattern, and therefore will not be described here.

[0075] (Second embodiment) Fig. 29 is a diagram showing a flowchart of a method for visualizing a latent image from image data of a latent pattern in the second embodiment. Up until now, image data has been reduced by a pinch operation by a user, but the flowchart in Fig. 29 is a method for visualizing a latent image by automatically reducing image data through image processing in a terminal (4) having at least a storage unit (101), a display unit (102), and an image processing unit (103).

[0076] First, an application is started on the terminal (4) (STEP 1), and image data of the latent image pattern to be visualized as a latent image is acquired (STEP 2). In this embodiment, an example will be described in which image data stored in an external database is acquired as the storage unit (101). An example of an external database is image data of products put up for sale on an internet auction site. When a latent image pattern is applied to the package or body of a product, and the part with the applied latent image pattern is put up for sale as the product image, the image data is acquired.

[0077] Next, the acquired image data is displayed on the display, which is the display unit (102) (STEP 3). The application is not particularly limited in form, as long as it has at least the function of displaying image data of the latent image pattern on the display and reducing the image data.

[0078] Next, the image data is corrected by the image processing unit (103) (STEP 4). The correction in STEP 4 is not necessarily required, but if, for example, the latent image pattern is stored as image data in an inclined state, it is preferable to perform the correction, as this will visualize a latent image with less noise.

[0079] An example of image data correction will be described using Figures 30 and 31. Figure 30 is a diagram showing an example in which the latent image pattern (10) shown in Figure 2(b) is photographed while tilted at a predetermined angle (θ1). Here, the angle formed by a virtual line (51) tangent to the bottom side of the latent image pattern (10) and a reference line (50) that is the bottom side of the image data itself is described as the predetermined angle (θ1). Note that the virtual line (51) is shown for convenience of explanation, but does not actually exist.

[0080] Next, correction data, which is a parameter required to correct the image data, is acquired from the storage unit 101. The correction data is a reference angle and the like for visualizing an appropriate latent image when the image data of the latent image pattern 10 is reduced.

[0081] Next, the angle (θ1), which is the tilt of the latent image pattern (10) displayed on the display (4a), is compared with the reference angle, which is the correction data, to determine whether it is a specified value. If the specified value is 0 degrees, the latent image pattern (10) shown in Figure 30 is tilted by a specified angle (θ1), so the angle (θ1) of the latent image pattern (10) does not match the specified value, and angle correction is therefore performed. If they match, angle correction is omitted. As an example, the angle of the image data can be corrected using affine transformation.

[0082] FIG. 31 is a diagram showing the latent image pattern (10) shown in FIG. 30 after angle correction. When angle correction is performed, the image size of the image data increases depending on the angle, but this is not a problem. However, cropping may be performed as needed. In addition, processing such as adjusting the contrast may be performed to improve the visibility of the image data.

[0083] Next, the image data is reduced by the image processing unit (103) (STEP 5), and the reduction process is stopped when the latent image is visualized (STEP 6). Methods for detecting that the latent image has been visualized include detection by pattern matching and detection by spatial frequency.

[0084] An example of a method for detecting by pattern matching will be described below. A reference image that serves as a reference for the latent image is stored in advance in the storage unit (101), and by pattern matching each image data with the reference image while reducing the image data of the latent pattern, it is possible to detect that the latent image has been visualized.

[0085] Next, an example of a method for detection using spatial frequency will be described. As the image data of the latent image pattern is reduced, it is possible to detect that the latent image has been visualized by detecting using the spatial frequency obtained by performing a Fourier transform on each image data. This is because, while a frequency component with a period corresponding to the pitch of multiple latent image elements is detected in the latent image pattern before reduction, the latent image reproduced by thinning out the latent image elements due to reduction of the image data of the latent image pattern has a longer wave period. In other words, this method utilizes the fact that the frequency differs before and after reduction of the image data.

[0086] The detection method is not limited to these, and any method can be used as long as it is capable of capturing the change between image data before and after reduction. In the present invention, if the image data is reduced to a value smaller than a predetermined reduction rate, the normal latent image will not be visualized, so it is preferable to use a method of detecting that the latent image has been visualized and stopping the reduction process, as in this embodiment.

[0087] With the configuration of this embodiment, if a latent image pattern is applied to the packaging or body of a product, even if the customer does not actually have the product in their hands, they can reduce the image data of the product on the display to confirm that the latent image is visualized, and can then purchase the product after confirming that it is not a counterfeit.

[0088] (Third embodiment) 32 is a diagram showing a flowchart of a method for visualizing a latent image from image data of a latent pattern in the third embodiment. In this embodiment, the method reduces image data of the captured latent pattern by a terminal (4) having at least a storage unit (101), a display unit (102), an image processing unit (103), and an imaging unit (105), and visualizes the latent image.

[0089] First, the application is started on the terminal (STEP 1), and the latent image pattern to be visualized as a latent image is captured by the camera, which is the imaging unit (105) (STEP 2). Image data of the captured latent image pattern is stored in the memory unit (101) of the terminal (4).

[0090] When capturing an image of the latent image pattern, pre-processing may be performed to optimize the capturing conditions such as the inclination of the latent image pattern, etc. An example of the pre-processing will be described with reference to Figs.

[0091] Fig. 33 shows an imaging assistance line (52) displayed on the display (4a) during imaging. By adjusting the edge of the latent image pattern (10) displayed on the display (4a) during imaging so that it is aligned with the imaging assistance line (52), it is possible to reduce the tilt of the latent image pattern (10). Note that the imaging assistance line (52) in Fig. 33 is merely an example, and it is also possible to use a form that surrounds the pattern in a square or a form that displays only the four corners.

[0092] 34 shows an announcement displayed on the display (4a) during imaging. An imaging assistance line (52), which serves as a reference for imaging, is displayed on the display (4a) within the imaging screen, and the terminal (4) guides the user to achieve optimal imaging conditions, allowing the user to capture an image and suppress the tilt of the latent image pattern (10). Note that the announcement is not limited to what is displayed on the display (4a), and may be an audio announcement.

[0093] In Fig. 35, an imaging assistance line (52) serving as a reference for imaging is displayed on the display (4a) during imaging, and the user adjusts the camera position so that the latent image pattern (10) fits into the imaging assistance line (52), and the timing at which it fits is detected by the terminal (4) and an image is taken, thereby making it possible to suppress the tilt of the latent image pattern (10). The pre-processing shown in Figs. 33 to 35 may be used alone, but by using them in combination, it becomes possible to minimize the tilt of the latent image pattern (10). In addition, well-known correction processing such as depth correction and lens correction may be performed.

[0094] Next, image data of the latent image pattern is read from the storage unit (101) and displayed on the display (4a) which is the display unit (102) (STEP 3). At this point, the image data may be corrected by the image processing unit (103) as described in the second embodiment.

[0095] Next, the image data is reduced (STEP 4), and the latent image is visualized (STEP 5). The image data reduction process can be performed by the pinch operation by the user as described in the first embodiment, or by the image processing as described in the second embodiment.

[0096] (Fourth embodiment) 36 is a diagram showing a flowchart of a method for visualizing a latent image from image data of a latent pattern and determining authenticity in the fourth embodiment. In this embodiment, the method reduces image data of a captured latent pattern using a terminal (4) having at least a storage unit (101), a display unit (102), an image processing unit (103), and an imaging unit (105), and determines authenticity based on the visualized latent image.

[0097] In Fig. 36, steps 1 to 5 are the same as those in the first or second embodiment, and therefore a description thereof will be omitted. The latent image visualized in step 5 is compared with the authenticity determination data stored in advance in the storage unit (101) by the image processing unit (103) to determine authenticity (step 6). The authenticity determination data is image data, feature amounts, etc. of the authentic latent image. The method of comparison and determination is not particularly limited, and methods such as pattern matching, edge extraction, and feature point extraction can be used.

[0098] FIG. 37 illustrates a configuration in which the terminal (4) further includes an input unit (104), allowing the user to visualize the latent image (3) more easily. The terminal (4) shown in FIG. 37 has a display unit (102) with a touch panel function, and therefore also includes the function of the input unit (104). FIG. 37(a) shows the state in which image data of the latent image pattern (10) is displayed on the display (4a) of the terminal (4), and the magnification of the image data and a magnification change means (60) serving as the input unit (104) are further arranged below the display (4a). The user can enlarge or reduce the image data displayed on the display (4a) by operating the up and down buttons of this magnification change means (60).

[0099] Figure 37(b) shows the state in which the magnification changing means (60) is operated to reduce the original image data to 50%, and at this point the latent image (3) is not yet visible, but as shown in Figure 37(c), by reducing it to 5%, the latent image (3) becomes visible. In this way, by having the magnification changing means (60), the user does not need to enlarge and reduce the image data multiple times, and it becomes possible to visualize the latent image (3) more easily.

[0100] The latent image of the present invention is visualized by reducing the image data of the latent image pattern, and if the latent image becomes too small and is difficult for the user to see, the image data of the visualized latent image may be obtained and enlarged and displayed in an area on the display separate from the area of ​​the reduced image data of the latent image pattern.

[0101] (software) The latent image visualization software of the present invention causes a computer provided in a terminal to execute the above-mentioned method for visualizing a latent image from image data of a latent image pattern.

[0102] The software for authenticity determination of the present invention causes a computer provided in a terminal to execute a method for visualizing a latent image from image data of the above-mentioned latent image pattern and determining authenticity.

[0103] The latent image visualization method and visualization software described above makes it possible to easily visualize a latent image by utilizing a device with a display, such as a smartphone, which is carried by the majority of people.

[0104] 1 Base material 2. Discrimination tool 3, 13, 23, 33, 43 Latent images 4. Terminal 4a Display 5 subpixels 5a Subpixel R 5b Subpixel G 5c Subpixel B 5d Subpixel Black 5e Subpixel Gray 10, 20, 30, 40 latent image pattern 11. Colored Elements 11A Latent image area 11B Background part 22, 42, 42-1, 42-2, 42-n Latent image elements 12A1 First latent image element 12A2 Second latent image element 12A3 Third latent image element 14 Filter Elements 21, 31, 41 base images 44-1, 44-2, 44-3, 44-16, 44-28, 44-n frames 45-1, 45-2, 45-3, 45-16, 45-28, 45-n Images in frames 50 Baseline 51 Virtual Line 52 Imaging auxiliary line 60 Magnification change method 101 Storage section 102 Display section 103 Image processing section 104 Input section 105 Imaging unit 106 External connection part

Claims

1. A latent image visualization method for visualizing a latent image concealed by a latent image pattern from image data of the latent image pattern having a plurality of latent image elements that are periodically sampled to visualize the latent image, by using a terminal having at least a display unit, an image processing unit, and either a storage unit or an imaging unit, comprising: displaying, on the display unit, image data of the latent image pattern captured by the imaging unit or image data of the latent image pattern stored in advance in the storage unit; A latent image visualization method, characterized in that the latent image is visualized on the display unit by a step of reducing image data of the latent image pattern by the image processing unit.

2. 2. The latent image visualization method according to claim 1, further comprising a step of detecting that the latent image has been visualized by the image processing unit and terminating the reduction process.

3. A method for determining authenticity of a latent image, characterized in that the latent image visualized using the latent image visualization method described in claims 1 and 2 is compared with authenticity determination data previously stored in the memory unit to determine the authenticity of the latent image pattern.

4. 3. Software for visualizing a latent image, which causes a computer provided in the terminal to execute the latent image visualizing method according to claim 1 or 2.

5. 4. Software for authenticity determination, which causes a computer provided in the terminal to execute the authenticity determination method according to claim 3.

Images