Method for reading latent images from a latent image generator and software for reading latent images

Abstract

This invention provides a latent image reading method and software for reading latent images, which reveal the latent image of a latent image-forming body through image processing. [Solution] The method for reading a latent image from a latent image forming body includes: acquiring base image data; acquiring the total number of latent image elements constituting the latent image forming body; acquiring a virtual lens pitch corresponding to the pitch between latent image element data constituting each latent image element group data; generating divided image data by dividing the base image data and generating a plurality of divided image data; generating latent image pattern data by sequentially combining a plurality of divided image data at the period of the virtual lens pitch from the divided image data while changing the starting position for combining the divided image data, thereby generating a plurality of latent image pattern data; and displaying the plurality of latent image pattern data in the order in which the latent image pattern data were generated.

Description

[Technical Field]

[0001] This invention relates to a method for reading latent images from a latent image forming apparatus and software for reading latent images. [Background technology]

[0002] In the field of valuable printed materials such as banknotes, passports, securities, identification cards, and travel tickets, where anti-counterfeiting effects are required, anti-counterfeiting technologies are employed to prevent fraudulent activities such as forgery and alteration.

[0003] One of these anti-counterfeiting techniques involves creating a latent image by dividing a specific original image, and then printing it onto a substrate. This valuable print can be reproduced by a discriminator using a discriminator tool such as a lenticular lens or line film. The discriminator can then determine the authenticity of the valuable print based on the reproduced image. A specific example is shown below.

[0004] Figure 1(a) shows a latent image forming body (S) on which a latent image (A1) has been applied to a substrate (13), and Figure 1(b) shows the original image (A1') that serves as the basis for forming the latent image (A1). Figure 2(a) shows the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) that constitute the latent image (A1), and Figure 2(b) is an enlarged view of a part of the latent image (A1) shown in Figure 2(a) (the area enclosed by the dotted line).

[0005] As shown in Fig. 2(a), the plurality of latent image element groups (1a, 2a, 3a) are obtained by dividing the image of "cherry blossoms" that becomes the original image (A1´) in the first direction (S1). The first latent image element group (1a) consists of a plurality of latent image elements (1a-1, 1a-2, ···, 1a-n (where n is a natural number of 2 or more)), the second latent image element group (2a) consists of a plurality of latent image elements (2a-1, 2a-2, ···, 2a-n), and the third latent image element group (3a) consists of a plurality of latent image elements (3a-1, 3a-2, ···, 3a-n). And as shown in Fig. 2(b), the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) are regularly arranged in sequence without overlapping each other.

[0006] Note that the centers (О) of the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) overlap at the same position. The second latent image element group (2a) and the third latent image element group (3a) are obtained by dividing the original image (A1´) of the cherry blossoms rotated by θ1 degrees and θ2 degrees respectively in the direction of T1, and are used as respective element groups.

[0007] And as shown in Fig. 3, the discriminator overlays the lenticular lens (14a) on this latent image (A1), and by shifting the lenticular lens (14a) in the first direction (S1), the elements of the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) are enlarged in order. As a result, the first latent image pattern (1b), the second latent image pattern (2b), and the third latent image pattern (3b) are reproduced in order. At this time, the discriminator makes a true / false determination based on whether the plurality of latent image patterns (1b, 2b, 3b) are correctly reproduced.

[0008] Alternatively, in a lenticular image forming body (S) formed by laminating a lenticular lens (14a) so as to overlap a latent image (A1), when a discriminator visually recognizes the lenticular image forming body (S) and changes the viewing angle, the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) are each visually recognized with the elements enlarged in order, and as a result, the first latent image pattern (1b), the second latent image pattern (2b), and the third latent image pattern (3b) are reproduced in order.

[0009] Incidentally, methods for imparting a latent image (A1) to the latent image forming body (S) include printing with ordinary ink, printing with special ink that develops under specific conditions, and watermarking.

[0010] Next, a technique for latent imaging an original image by compressing the original image will be described. For example, the latent image (A2) shown in FIG. 4(a) consists of a first latent image element group (1a) in which latent image elements (1a-1) shown in FIG. 4(b) are arranged in a first direction (S1) at a constant pitch (L´) as shown in FIG. 4(a). The latent image element (1a-1) itself is obtained by compressing the original image (A2´) shown in FIG. 4(b) to an arbitrary element width (P) in the first direction (S1).

[0011] When a discriminator overlays a lenticular lens (14a) on this latent image (A2) and moves the lenticular lens (14a) in the first direction (S1) shown in FIG. 4, moiré occurs and the original image (A2´) is reproduced with a dynamic effect. In order to generate moiré, the pitch (L´) of the arrangement of the latent image elements (1a-1) and the lens pitch (L) of the lenticular lens (14a) need to be different. Specifically, when the pitch (L´) of the arrangement of the latent image elements (1a-1) is set to 100%, the lens pitch (L) of the lenticular lens (14a) is 80% or more and 120% or less excluding 100%.

[0012] Next, we will explain a technique for creating a latent image from an original image by dividing and compressing the original image. The latent image (A3) shown in Figure 5(b) is formed by dividing the original image (A3') of the cherry blossom pattern in Figure 5(a), changing the cropping position, dividing it in a first direction (S1) to a predetermined size, and then compressing it to a predetermined element width (P). The latent image elements have the same pitch (L') as the lenticular lens (14a).

[0013] When the discriminator superimposes a lenticular lens (14a) onto this latent image (A3) and moves the lenticular lens (14a) in the first direction (S1) shown in Figure 5, the original image of the cherry blossom pattern (A3') is reproduced with a dynamic effect.

[0014] The applicant has filed an application for a transmitted latent image manifestation structure and a transmitted latent image forming body equipped therewith, in which these latent image images (A1, A2, A3) are applied to a substrate (13) as a watermark, so that the latent image is invisible under reflected light, so as not to affect the design of the printed material, and to prevent counterfeiting, and the image changes depending on the observation angle under transmitted light (see, for example, Patent Document 1).

[0015] Next, we will explain a technique for creating a latent image from an original image by compressing the original image from two directions (see, for example, Patent Document 2). For example, Figure 6(a) shows a latent image forming body (S) on which a latent image (A4) is applied to a substrate (13), Figure 6(b) is an enlarged view of a part of the latent image (A4), and Figure 6(c) shows the original image (A4') that forms the basis of the latent image (A4). The latent image (A4) is formed by compressing the original image (A4') shown in Figure 6(c) into latent image elements (41a-1-1, ..., 41a-2-2) to have an arbitrary width (P) in the first direction (S1) and second direction (S2) shown in Figure 6(b), and arranging multiple latent image elements (41a-1-1, ..., 41a-2-2) at a constant pitch (L') in the first direction (S1) and second direction (S2), thereby forming a group of latent image elements (41a).

[0016] Figure 7(a) shows a lens array (14b) in which multiple dot-shaped lenses are arranged in a first direction (S1) and a second direction (S2) at arbitrary lens pitches (L). Figure 7(b) shows the positional relationship when the lens array (14b) is stacked on the latent image (A4) shown in Figure 6(a). The lens pitch (L) of the lens array (14b) must be different from the pitch (L') of the latent image elements (41a-1-1, ..., 41a-2-2) that form the latent image (A4). Specifically, if the pitch (L') of the arrangement of the latent image elements (41a-1-1, ..., 41a-2-2) is 100%, the lens pitch (L) of the lens array (14b) must be between 80% and 120%, excluding 100%.

[0017] Figure 8 shows the latent image pattern (1b) that is reproduced with a dynamic effect when the lens array (14b) is superimposed on the latent image forming body (S). This latent image pattern (1b) is produced when moiré is generated due to the different arrangement pitches of the latent image elements (41a-1-1, ..., 41a-2-2) and the lens array (14b), and the original image (A4') is reproduced by the moiré expansion phenomenon. Furthermore, the latent image pattern (1b) can be dynamically viewed when the lens array (14b) is moved on the latent image forming body (S), or when the viewing angle of the discriminator when viewing the latent image forming body (S) is changed.

[0018] Next, a technique for creating a latent image from an original image by dividing and compressing the original image from two directions will be described (see, for example, Patent Document 3). For example, Figure 9(a) shows a latent image forming body (S) to which a latent image (A5) has been applied to a substrate (13), and Figure 9(b) shows an enlarged view of a part of the latent image (A5) and the original image (A5'). The latent image (A5) shown in Figure 9(a) consists of a group of latent image elements (41a) in which the original image (A5') shown in Figure 9(b) is cut out to a predetermined size by changing the cutting position, and latent image elements (41a-1-1, ..., 41a-3-3) are compressed to have an arbitrary width (P) in the first direction (S1) and second direction (S2) shown in Figure 9(b), and are arranged in the first direction (S1) and second direction (S2) at a constant pitch (L'). In this case, the pitch (L') of the latent image elements (41a-1-1, ..., 41a-3-3) and the lens pitch (L) of the lens array (14b) are the same. Note that in the latent image forming body (S) described in Patent Document 3, a group of elements having raised and luminous properties is included as a configuration to replace the lens array (14b), but in this example, the latent image forming body (S) does not have a group of elements having raised and luminous properties because it uses the lens array (14b) to produce a latent image.

[0019] Figure 10 shows the latent image pattern (1b) that can be seen when the discriminator superimposes the lens array (14b) onto the latent image (A5). The latent image pattern (1b) can be seen dynamically when the discriminator moves the lens array (14b) over the latent image forming body (S), or when the discriminator changes the observation angle when viewing the latent image forming body (S).

[0020] The latent image elements that make up the aforementioned latent images (A1, A2, A3, A4, A5) come in two types: line-shaped and dot-shaped. The latent image elements that make up the latent image images (A1, A2, A3) are line-shaped, while the latent image images (A4, A5) consist of dot-shaped latent image elements.

[0021] Furthermore, although it does not involve the same elemental configuration as the latent image (A1, A2, A3, A4, A5) described above, the applicant has also filed an application for anti-counterfeiting printed materials as a technique for generating a latent image using a lenticular lens (14a) (see, for example, Patent Document 4).

[0022] Figure 11(a) shows an example of a latent image forming body (S) described in Patent Document 4, in which a latent image (A6) is formed on a substrate (13). The latent image (A6) consists of a first visible image (22a) of a large cherry blossom that can be seen with the naked eye without using a lenticular lens (14a), a second visible image (22b) of many small cherry blossoms, and an invisible image (22c) that is invisible to the naked eye, shown by a dotted line in the figure. By using a lenticular lens (14a), the first latent image pattern (1b) and the second latent image pattern (2b), which will be described later, become visible in the invisible image (22c).

[0023] The latent image (A6) consists of units (U) in which a first line element (1a'), a second line element (2a'), a third line element (3a'), and a fourth line element (4a') are formed, as shown in Figure 11(b). The latent image (A6) is formed by arranging multiple such units (U) in a matrix. In this example, the shape of the units (U) is square. The first line element (1a') and the second line element (2a') form an invisible image (22c), the third line element (3a') forms the first visible image (22a), and the fourth line element (4a') forms the second visible image (22b).

[0024] Next, the relationship between the first image element (1a') that forms the invisible image (22c) and the lenticular lens (14a) will be explained. Figure 12(a) shows the positional relationship when the vertices of the convex portion of the lenticular lens (14a) are superimposed on multiple first image elements (1a'). In the example shown in Figure 12, the pitch (L) of the lenticular lens (14a) is four times the element width (P) of the first image element (1a') and the second image element (2a'). Also, the height and width (Us) of the unit (U) and the pitch (L) of the lenticular lens (14a) are the same.

[0025] Figure 12(b) shows the visible invisible image (22c) when the lenticular lens (14a) is superimposed on a portion of the latent image (A6) at a position where the vertex of the convex part of the first image element (1a') overlaps. The lenticular lens (14a) enlarges the width (P) of the first image element (1a'), and as a whole, produces the first latent image pattern (1b) shown in Figure 13(a). Furthermore, when the lenticular lens (14a) is superimposed on a second image element (2a') at a position where the vertex of the convex part of the lenticular lens (14a) overlaps, it produces the second latent image pattern (2b) shown in Figure 13(b).

[0026] Furthermore, even with the third image element (3a') and the fourth image element (4a'), if the lenticular lens (14a) is superimposed at a position where the vertex of the convex part of the lenticular lens (14a) overlaps with the third image element (3a') and the fourth image element (4a'), the first visible image (22a) and the second visible image (22b) can be viewed separately, respectively.

[0027] As described above, when determining the authenticity of a latent image-forming body (S), simple discriminators such as lenticular lenses (14a) or microfilm are used to confirm the latent image. However, since not everyone always carries such discriminators, there was a problem in that authenticity could not be determined.

[0028] Furthermore, when visualizing the latent image, there was a problem in that the latent image could not be confirmed because the design dimensions intended during the design of the latent image forming body (S) did not match the dimensions of the discriminator (for example, the pitch of the lenticular lens). There are two possible causes for this mismatch in dimensions: one is due to the discriminator's skill, such as not overlapping the latent image forming body (S) and the discriminator (14a, 14b) without any gaps, or not accurately matching the angle at which the latent image appears on the latent image forming body (S) with the angle of the discriminator (14a, 14b); and the other is due to the object itself, such as a manufacturing defect in either the latent image forming body (S) or the discriminator (14a, 14b), deformation due to the material of the base material (13) and the usage environment (temperature, humidity, etc.). As described above, the discriminator required time to precisely superimpose the discriminator (14a, 14b) onto the latent image forming body (S) at the correct distance and angle, and there was a risk that the visibility of the latent image would decrease due to deformation of the shape of the substrate (13) and the discriminator (14a, 14b).

[0029] Therefore, instead of the method in which a discriminator uses a discriminator to reveal a latent image and then determine its authenticity, methods have been proposed in which a latent image is read from a latent image forming body using a widely available smartphone or tablet device with camera functionality, or a machine terminal such as a camera, scanner, or line sensor capable of capturing images and a personal computer for image processing, as well as reading devices and reading software (see, for example, Patent Documents 5 and 6).

[0030] The technology described in Patent Document 5 is an invention relating to a reading method, reading device, and reading program for photographing a latent image forming body described in Patent Document 4 using a smartphone or tablet terminal with a camera function, performing image processing on the captured image, and displaying the latent image pattern on a multi-functional terminal.

[0031] Furthermore, the technology described in Patent Document 6 is an invention characterized by photographing a latent image forming body described in Patent Document 4, setting a predetermined pixel in the captured image as a reference point, and reading and authenticating the latent image pattern by performing reduction, enlargement, and interpolation processing while moving the reference point. [Prior art documents] [Patent Documents]

[0032] [Patent Document 1] Patent No. 6966747 [Patent Document 2] Patent No. 5527969 [Patent Document 3] Patent No. 5200284 [Patent Document 4] Patent No. 4635160 [Patent Document 5] Patent No. 7024982 [Patent Document 6] Patent No. 6979694 [Overview of the project] [Problems that the invention aims to solve]

[0033] However, the method for reading latent image patterns described in Patent Document 6 is a method for reading only the invisible image (22c) from a latent image (A6) which comprises visible images (22a, 22b) and an invisible image (22c) as shown in Figure 11. It does not disclose a specific method for reading latent images (A1, A2, A3, A4, A5) obtained by dividing or dividing and compressing the original image, as shown in Figures 1 to 10. Specifically, the method of Patent Document 6 could not reproduce the continuously changing latent images of the three rotating latent image patterns (1b, 2b, 3b) shown in Figure 3, the original image (A2') shown in Figure 4(b), the original image (A3') shown in Figure 5(a), the original image (A4') shown in Figure 6(c), and the original image (A5') shown in Figure 9(b).

[0034] The present invention aims to solve the above-mentioned problems and to provide a latent image reading method and latent image reading software that reveals a latent image of a latent image forming body having elements that form a latent image through image processing. [Means for solving the problem]

[0035] The present invention provides a latent image reading method for a latent image forming body, in which a latent image is formed on a substrate, wherein the original image is formed by a latent image forming body in which a latent image is formed by a first latent element group, ..., a mth latent element group (m being an integer of 2 or more) consisting of a plurality of latent image elements divided in a first direction, arranged sequentially from the first to the mth group without the latent image elements constituting each group overlapping, and the reading method is provided by a reading device that includes at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, comprising a base image data acquisition step of reading the latent image with the image acquisition unit and acquiring base image data consisting of first latent element group data, ..., the mth latent element group data corresponding to each of the first latent element group, ..., the mth latent element group The method is characterized by comprising: an image acquisition step; a total number acquisition step for acquiring the total number of latent image element groups; a virtual lens pitch acquisition step for acquiring a virtual lens pitch corresponding to the pitch between latent image element data constituting each latent image element group data; a divided image data generation step for generating multiple divided image data by dividing the base image data by a latent image element pitch width which is the value obtained by dividing the virtual lens pitch by the total number of latent image element groups in the direction in which the latent image element data are arranged; a latent image pattern data generation step for generating multiple latent image pattern data by sequentially combining multiple divided image data that are in the period of the virtual lens pitch while changing the starting position for combining the divided image data from the divided image data; and an image display step for displaying the multiple latent image pattern data in the order in which the latent image pattern data were generated.

[0036] Furthermore, the latent image reading method of the latent image forming apparatus of the present invention is characterized by having an enlargement processing step that enlarges a plurality of segmented image data generated by the segmented image data generation step.

[0037] Furthermore, the latent image reading method of the latent image forming body of the present invention is characterized by having a preprocessing step that includes a preprocessing step of correcting at least one of the size and angle of the base image data acquired in the base image data acquisition step.

[0038] Furthermore, the latent image reading method of the latent image forming body of the present invention includes a cropping position calculation step in which, in the segmented image data generation step, an initial cropping position that serves as the starting point for segmentation is calculated for segmenting the base image data into latent image element data corresponding to each latent image element, and in the latent image pattern data generation step, the total number of generated latent image pattern data is equal to the total number of latent image element groups by segmenting the base image data starting from the cropping position calculated in the cropping position calculation step.

[0039] Furthermore, the extraction position calculation step of the latent image reading method for a latent image forming body of the present invention is characterized by comprising: a step of obtaining a reference image or feature data corresponding to a reference image for calculating an initial extraction position that will serve as the starting point for division, in order to divide the base image data into latent image element data corresponding to each latent image element; a step of obtaining latent pattern data that is the same number as the latent image element pitch value and has different extraction positions for each pixel, or feature data that is the same number as the latent image element pitch value and has different extraction positions for each pixel; a step of calculating at least one of the degree of agreement between the reference image and each latent image pattern data and the degree of agreement between the feature data corresponding to the reference image and each feature data corresponding to latent image pattern data with a different extraction position; and a step of setting the extraction position associated with the latent image pattern data or feature data corresponding to the latent image pattern data with the highest degree of agreement as the initial extraction position.

[0040] The present invention provides a latent image reading method for a latent image forming body, which has a latent image formed in which a plurality of latent image elements, obtained by dividing and compressing an original image in a predetermined direction, are arranged at a constant pitch in a predetermined direction, and the reading method is performed by a reading device comprising at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, the method comprising an image acquisition step which includes If the element is one of the latent image elements, the image display step comprises: a virtual lens pitch acquisition step that acquires a virtual lens pitch corresponding to an arrangement pitch of 80% to 120% excluding 100%, assuming the arrangement pitch of the latent image element data is 100%; a divided image data generation step that divides the base image data from the base image data in a predetermined direction with a predetermined width for reconstructing the original image, and generates a plurality of divided image data; a latent image pattern data generation step that sequentially combines a plurality of divided image data at the period of the virtual lens pitch from the divided image data, while changing the starting position for combining the divided image data, and generates a plurality of latent image pattern data; and an image display step that displays the plurality of latent image pattern data in the order in which the latent image pattern data were generated.

[0041] Furthermore, the latent image reading method of the latent image forming apparatus of the present invention is characterized by having an enlargement processing step that enlarges a plurality of segmented image data generated by the segmented image data generation step.

[0042] Furthermore, the latent image reading method of the latent image forming body of the present invention is characterized by having a preprocessing step that includes a preprocessing step of correcting at least one of the size and angle of the base image data acquired in the base image data acquisition step.

[0043] Furthermore, the latent image reading method of the latent image forming body of the present invention is characterized in that, in the latent image pattern data generation step, the total number of latent image pattern data generated is equal to the number of pixels of the virtual lens pitch.

[0044] Furthermore, the method for determining the authenticity of a latent image forming body according to the present invention is characterized by comprising the step of determining authenticity using a plurality of latent image pattern data generated using a latent image reading method.

[0045] Furthermore, the latent image reading software for the latent image forming body of the present invention is characterized by causing a computer to execute the latent image reading method for the latent image forming body of the present invention.

[0046] Furthermore, the software for determining the authenticity of a latent image forming body according to the present invention is characterized by causing a computer to execute the method for determining the authenticity of a latent image forming body according to the present invention.

[0047] Furthermore, the latent image reading method of the latent image forming body of the present invention is a latent image forming body in which a latent image is formed on a substrate, in which a latent image is formed in which a first latent element group, ..., a mth latent element group (m is an integer of 2 or more) consisting of a plurality of latent image elements divided in a first direction is arranged sequentially from the first to the mth group without the latent image elements constituting each group overlapping, and the reading method is read by a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, and comprises an image acquisition step which includes an image acquisition step which includes reading the latent image with the image acquisition unit and acquiring base image data consisting of first latent element group data, ..., a mth latent element group data corresponding to each of the first latent element group, ..., a total number acquisition step which includes acquiring the total number of latent element groups and each latent image group data which includes The image acquisition process includes a virtual lens pitch acquisition step of acquiring a virtual lens pitch corresponding to the pitch between latent image element data; a divided image data generation step of dividing the base image data by a latent element pitch width which is the value obtained by dividing the virtual lens pitch by the total number of latent image elements in the direction in which the latent image element data are arranged, and generating a plurality of divided image data; a latent pattern data generation step of sequentially combining a plurality of divided image data which are in the period of the virtual lens pitch in order to synthesize the divided image data, and generating latent pattern data; and an image display step of displaying the latent pattern data in the order in which the latent pattern data were generated, wherein at least the base image data acquisition step of the image acquisition process and the divided image data generation step, latent pattern data generation step, and image display step of the image display process are performed while moving either the reader or the latent image forming body in a predetermined direction.

[0048] Furthermore, the latent image reading method of the latent image forming body of the present invention is a latent image reading method that reads a latent image forming body having a latent image formed in which a plurality of latent image elements, obtained by dividing and compressing or compressing an original image in a predetermined direction, are arranged at a constant pitch in a predetermined direction, using a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, comprising an image acquisition step of acquiring base image data including a base image element unit consisting of latent image element data corresponding to the latent image elements, and the configuration of the latent image elements is The image acquisition process comprises: (i) if the original image is an element divided and compressed in a predetermined direction, a virtual lens pitch corresponding to the arrangement pitch of the latent image element data is acquired; or (ii) if the original image is an element compressed in a predetermined direction, a virtual lens pitch acquisition step is acquired to acquire a virtual lens pitch corresponding to an arrangement pitch of 80% to 120% excluding 100%, assuming the arrangement pitch of the latent image element data is 100%; a divided image data generation step is performed by dividing the base image data in a predetermined direction with a predetermined width for reconstructing the original image, thereby generating a plurality of divided image data; a latent image pattern data generation step is performed by sequentially combining a plurality of divided image data at the period of the virtual lens pitch from the divided image data in order to synthesize the divided image data, thereby generating latent image pattern data; and an image display step is performed by displaying the latent image pattern data in the order in which the latent image pattern data was generated. The image acquisition process is characterized by performing at least the base image data acquisition step of the image acquisition process and the divided image data generation step, latent image pattern data generation step, and image display step of the image display process while moving either the reader or the latent image forming body in a predetermined direction.

[0049] Furthermore, the method for determining the authenticity of a latent image forming body according to the present invention is characterized by comprising the step of determining authenticity using a plurality of latent image pattern data generated using a latent image reading method.

[0050] Furthermore, the latent image reading software for the latent image forming body of the present invention is characterized by causing a computer to execute the latent image reading method for the latent image forming body of the present invention.

[0051] Furthermore, the software for determining the authenticity of a latent image forming body according to the present invention is characterized by causing a computer to execute the method for determining the authenticity of a latent image forming body according to the present invention. [Effects of the Invention]

[0052] According to the latent image reading method and latent image reading software for a latent image forming body of the present invention, instead of using a discrimination device that is only available to a limited number of people, it is possible to acquire image data of the latent image attached to the latent image forming body using a commonly available smartphone, tablet, or PC, perform image processing, and display it on the screen, thereby revealing the latent image of the latent image attached to the latent image forming body. [Brief explanation of the drawing]

[0053] [Figure 1] Figure showing a latent image generator (S) to which a latent image (A1) has been added. [Figure 2] Figure showing a latent image (A1) consisting of multiple latent image element groups (1a, 2a, 3a). [Figure 3] A diagram showing a latent image forming element (S) with a lenticular lens (14a) superimposed on it. [Figure 4] Diagram showing the elemental structure of the latent image (A2) [Figure 5] Diagram showing the elemental structure of the latent image (A3). [Figure 6] Diagram showing the elemental structure of a latent image (A4) [Figure 7] Diagram showing the positional relationship between the latent image (A4) and the lens array (14b). [Figure 8] A diagram showing the lens array (14b) superimposed on the latent image forming body (S). [Figure 9] Diagram showing the elemental structure of the latent image (A5) [Figure 10] A diagram showing the lens array (14b) superimposed on the latent image forming body (S). [Figure 11] This figure shows a latent image generator (S) and a unit (U) to which a latent image (A6) has been added. [Figure 12]A diagram showing a latent image forming element (S) with a lenticular lens (14a) superimposed on it. [Figure 13] Diagram showing the first latent image pattern (1b) and the second latent image pattern (2b). [Figure 14] Figure showing a latent image former (S) with feature extraction marks (5) added. [Figure 15] Block diagram of the latent image reader (T) [Figure 16] Diagram showing the latent image reading device (T) [Figure 17] Flowchart of latent image reading method [Figure 18] Flowchart of the image acquisition process [Figure 19] Diagram showing guides on the display unit (T05) [Figure 20] Flowchart of the pre-treatment process (K20) [Figure 21] Diagram illustrating the correction method for the base image data (4) [Figure 22] Figure showing the angle correction applied to the original image data (4). [Figure 23] Diagram illustrating the elemental configuration of the base image element section (4α). [Figure 24] Diagram showing latent image pattern data on the display unit (T05). [Figure 25] Flowchart of the image display process (K30) [Figure 26] Figure showing the segmented image (7) [Figure 27] Figure showing display image data (6) [Figure 28] Figure showing display image data (6) with different cropping positions (t) [Figure 29] Flowchart of the image display process (K31) [Figure 30] Flowchart of the image display process (K32) [Figure 31] Flowchart of the image display process (K32) [Figure 32] Flowchart of the image display process (K32) [Figure 33] Figure showing the displayed image data (6) and its histogram (8). [Figure 34]Figure showing the reference histogram (8'). [Figure 35] Flowchart of the image display process (K32) [Figure 36] Figure showing an example of feature point extraction marks (5) [Figure 37] Figure showing an example of feature point extraction marks (5) [Figure 38] Figure showing the latent image former (S) [Figure 39] Flowchart of latent image reading method [Figure 40] Diagram showing guides on the display unit (T05) [Figure 41] Flowchart of the pre-processing step (K21) [Figure 42] Figure showing frequency conversion image data (18) [Figure 43] Detailed flow diagram of (S07) in the pre-treatment process (K21) [Figure 44] This diagram illustrates how to obtain the bounding rectangle of the base image element (4α). [Figure 45] Figure showing the latent image former (S) and the base image data (4). [Figure 46] Flowchart of latent image reading method [Figure 47] Detailed flow chart of the image display process (K33) [Figure 48] Figure showing the latent image former (S) and the base image data (4). [Figure 49] Flowchart of latent image reading method [Figure 50] Detailed flow chart of the pre-processing step (K22) [Figure 51] Detailed flow chart of the image display process (K34) [Figure 52] Figure showing latent image element data (41) [Figure 53] Diagram showing a chain code [Figure 54] Flowchart of the truth / false determination process (K40) [Figure 55] Detailed flowchart of the truth / false determination process (K40) [Figure 56] Outline diagram of the latent image reading system [Figure 57]Block diagram of server (32) [Figure 58] Block diagram of terminal (31) [Figure 59] Flowchart of a latent image reading system [Figure 60] Detailed flowchart of latent image pattern data generation (S500) [Figure 61] Flowchart of latent image reading method [Figure 62] Flowchart of the image acquisition process [Figure 63] Diagram showing the processing flow of the image processing unit (T02). [Figure 64] Flowchart of the pre-treatment process (K20) [Figure 65] Flowchart of the image display process (K35) [Figure 66] Flowchart of latent image reading method [Figure 67] Flowchart of the image display process (K36) [Figure 68] Flowchart of latent image reading method [Figure 69] Flowchart of the image display process (K37) [Modes for carrying out the invention]

[0054] Embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments described below, and includes various other embodiments as long as they are within the scope of the technical idea described in the claims.

[0055] (First Embodiment) First, a latent image reading device, latent image reading method, and latent image reading software for a latent image forming body (S) according to one embodiment of the present invention will be described. The latent image forming body (S) to be read will be described as an example where the latent image (A1) shown in Figure 14 is used. The latent image forming body (S) shown in Figure 14 has a latent image (A1) consisting of a first latent image element group (1a), a second latent image element group (2a), and a third latent image element group (3a), as described in Figures 1 and 2. Furthermore, two black circle feature point extraction marks (5), which are used to correct the tilt and size of image data generated during capture, are arranged to sandwich the latent image (A1).

[0056] (Latent image reader for latent image forming body (T)) First, the latent image reading device (T) for the latent image forming body (S) will be described. In this invention, the latent image reading device (T) can be a smartphone, tablet terminal, or PC with a camera function. Here, an example in which a smartphone is used as the latent image reading device (T) will be described.

[0057] Figure 15 is a block diagram showing the hardware of the latent image reading device (T). The latent image reading device (T) can be implemented using a PC, smartphone, or tablet terminal connected by a bus, comprising a control unit (T01), an image acquisition unit (T02), an image processing unit (T03), an input unit (T04), a display unit (T05), and a storage unit (T06). The latent image reading device (T) may also include a communication unit (T07) and an illumination unit (T08).

[0058] The control unit (T01) consists of a CPU, ROM, RAM, etc. The CPU calls and executes programs related to the processing of the latent image reading device (T) stored in the storage unit (T06), ROM, or other storage media, into a work area on the RAM. ROM is a non-volatile memory that permanently holds programs and data. RAM is a volatile memory that temporarily holds programs and data loaded from the storage unit (T06), ROM, etc., and also has a work area used by the control unit (T01) to perform various processing. The image acquisition unit (T02), image processing unit (T03), input unit (T04), display unit (T05), storage unit (T06), communication unit (T07), and illumination unit (T08) are all capable of communicating with the CPU.

[0059] The image acquisition unit (T02) uses commonly used means for acquiring images, such as a camera, scanner, area sensor, or line sensor.

[0060] The image processing unit (T03) performs image processing on the image data acquired by the image acquisition unit (T02) to reveal a latent image. The image processing unit (T03) also performs authenticity determination processing using authenticity determination data stored in the memory unit (T06).

[0061] The image processing unit (T03) has general image processing functions such as pattern matching means, resolution conversion means, size conversion means, angle correction means, color conversion means for converting the color mode of an image, cropping means, Fourier transform means, image division means, image duplication means, and image scaling means, and performs image processing by appropriately selecting each means. Furthermore, it may also have general image processing means for image processing, not limited to this description.

[0062] The input unit (T04) can use, for example, input buttons, a keyboard, and a mouse. The display unit (T05) can also function as an operation panel, receiving instructions from the applicator regarding image processing and instructions to take a picture.

[0063] The display unit (T05) may use, for example, a liquid crystal display or an organic EL display. The display unit (T05) may also have an integrated touch panel. It is then given data output from the image processing unit (T03) or the storage unit (T06) to display latent image pattern data or the result of authenticity determination.

[0064] The storage unit (T06) may be an HDD, SSD, flash memory, or the like. The storage unit (T06) stores the program executed by the latent image reader (T) during the image processing described later, the data necessary for program execution, the OS, etc. The program executed by the latent image reader (T) may also be stored in the ROM of the control unit (T01).

[0065] The communication unit (T07) is the interface through which the latent image reader (T) connects to the internet and exchanges data with an external server. The interface unit can communicate using infrared communication, wireless LAN, etc.

[0066] The latent image reader (T) may also have an illumination unit (T08) that matches the conditions under which the latent image appears, in order to acquire image data of the transmitted image and the latent image (A1) that appears under special light sources such as infrared light or ultraviolet light. For example, the illumination unit (T08) may be a normal LED, infrared LED illumination, ultraviolet LED illumination, light table, etc.

[0067] Figure 16 shows the latent image forming body (S), the latent image reading device (T), and the base image data (4), which is data of the captured latent image (A1), displayed on the display unit (T05) of the latent image reading device (T). The latent image reading device (T) has a camera (15), i.e., an image acquisition unit (T02), on the back of the display unit (T05) that captures the latent image (A1), and can capture the latent image (A1) of the latent image forming body (S) and store it as base image data (4) in the storage unit (T06) of the latent image reading device (T).

[0068] (Method for reading latent images) Next, the method for reading the latent image (A1) assigned to the latent image forming body (S) will be explained using the flowchart shown in Figure 17.

[0069] Figure 17 is a flowchart showing the steps of the latent image reading method. As shown in Figure 17, the process proceeds in the order of image acquisition (K10), preprocessing (K20), and image display (K30). However, if the preprocessing (K20) is not required, it is possible to omit the preprocessing (K20) step and proceed directly to the image display (K30). The details of each step are explained below.

[0070] (Image acquisition process) Figure 18 is a flowchart showing an example of the image acquisition process (K10). In this embodiment, the discriminator first operates the latent image reading device (T) to launch an application program that executes the latent image reading method of the present invention, which is pre-stored in the memory unit (T06). Subsequently, the latent image reading device (T) displays a menu screen (not shown) on the display unit (T05) and activates the image acquisition unit (T02) according to the discriminator's selection on the menu screen (S01). Specifically, a button to activate the image acquisition unit (T02) is displayed on the menu screen of the display unit (T05), and the base image data (4) is acquired based on the image acquisition operation by the discriminator (S02).

[0071] One method for acquiring the base image data (4), which is image data of the latent image forming body (S), by the image acquisition unit (T02) is to capture it using the camera (15) of the latent image reading device (T). The color mode of the captured image can be grayscale data or RGB data, and there are no particular limitations.

[0072] Additionally, the illumination unit (T08) may be activated as needed to capture the image in an environment that facilitates the acquisition of the base image data (4) of the latent image (A1). It is not always necessary to use the illumination unit (T08) of the latent image reader (T) when acquiring the base image data (4). For example, if the latent image (A1) is applied to the latent image forming body (S) in the form of a watermark, a light table may be used as external illumination. In this case, the latent image forming body (S) is placed on the light table, and the image is captured using the latent image reader (T). Furthermore, if the latent image (A1) is applied to the latent image forming body (S) using an ink that manifests under special light sources, it is necessary to select appropriate illumination according to the characteristics of the ink and acquire the base image data (4) while illuminating it. For example, if the latent image (A1) is formed using a fluorescent ink that does not manifest under normal light but emits light under ultraviolet or infrared light, it is advisable to use an ultraviolet or infrared light source as illumination to manifest the latent image (A1) and capture the image.

[0073] In the present invention, the image acquisition step (K10) is not limited to the method shown in Figure 18. Other methods include reading and acquiring an image of the latent image forming body (S) that has been previously captured and stored in the memory unit (T06), or receiving and acquiring an image from an external server or another mobile terminal via the communication unit (T07). A button for selecting one of these image acquisition methods is displayed on the menu screen, allowing the user to acquire an image as appropriate based on their operation. In addition to the camera (15), other commonly used image acquisition means such as scanners, area sensors, and line sensors can be used as specific means for acquiring image data of the latent image forming body (S).

[0074] Figure 19 shows an example of base image data (4) acquired by the image acquisition unit (T02). In this embodiment, when acquiring base image data (4), the image is captured so that the feature point extraction marks (5) are included. Through this capture, as shown in Figure 19, base image data (4) is acquired, consisting of a base image element portion (4α) corresponding to the latent image (A1), a background portion (4β) other than the base image element portion (4α), and a feature portion (4γ) corresponding to the feature point extraction marks (5).

[0075] Furthermore, Figure 19 shows a guide (16a) on the display unit (T05) to assist in image capture. The discriminator takes the image so that the feature point extraction marks (5) are within the frame of the circular guide (16a). This reduces the tilt of the image during capture, allowing the latent image (A1) to be captured at a size suitable for reading the latent image.

[0076] (Pre-treatment process) The preprocessing step (K20) is a process of correcting the base image data (4) obtained in the image acquisition step (K10). Specifically, it is a process of performing angle correction or scaling processing on the base image data (4) so ​​that it becomes image data suitable for image processing in the next step, the image display step (K30). Figure 20 is a detailed flowchart of the preprocessing step (K20). Figure 21 is a diagram showing an example in which the latent image forming body (S) shown in Figure 14 is photographed while tilted at a predetermined angle (θ4). Note that the base image data (4) shown in Figure 21 has an image size of X (pixel) × Y (pixel) and consists of a base image element part (4α), a background part (4β), and feature parts (4γ0, 4γ1). Furthermore, the line connecting the feature parts (4γ0, 4γ1) is called a "virtual line" and denoted by the symbol "i", and the distance between feature parts is denoted by the symbol "4γ k The angle between the lower edge of the base image data (4) and the imaginary line (i) is described as the inclination angle "θ4". Note that the imaginary line (i) is shown in the diagram for illustrative purposes but does not actually exist. The steps of the preprocessing process (K20) will be explained with reference to these diagrams.

[0077] First, the coordinates of the feature parts (4γ0, 4γ1) are obtained (S03). First, the positions of the feature parts (4γ0, 4γ1) are detected by performing pattern matching on the base image data (4) shown in Figure 21 using reference images of the feature parts (4γ0, 4γ1) that have been stored in the memory unit (T06) beforehand. Then, the coordinates of the feature parts (4γ0, 4γ1) are obtained. In this embodiment, the coordinates of the feature part (4γ0) located on the left are set to 4γ0(x1, y1), and the coordinates of the feature part (4γ1) located on the right are set to 4γ1(x2, y2).

[0078] Next, correction data, which consists of parameters necessary to correct the base image data (4) and is stored in the memory unit (T06) beforehand, is acquired (S04). The correction data includes, as shown in Figure 14, a reference distance (5k) between two feature point extraction marks (5) placed on the latent image forming body (S), a reference angle indicating the relative positional relationship and inclination between the feature point extraction marks (5) and the latent image (A1), and a virtual lens pitch (Lp) used when dividing the base image data (4) in the image display step (K30) described later. In this embodiment, the latent image (A1) and the feature point extraction marks (5) are aligned in a straight line, and the latent image (A1) is positioned at the center between the feature point extraction marks (5). The virtual lens pitch (Lp), which is one of the correction data, may be acquired in the image display step described later.

[0079] Next, based on the coordinates of the feature area (4γ0, 4γ1), the angle (θ4) between the feature area (4γ0, 4γ1) and the distance (4γk) between the feature areas are determined (S05). The base image data (4) may be acquired at an angle because the discriminator holds the latent image reader (T) in their hand when taking the image. Therefore, the angle (θ4) of the base image data (4) is corrected using the feature area (4γ0, 4γ1) of the base image data (4).

[0080] The imaginary line (i) connecting feature region (4γ0) and feature region (4γ1) is tilted at a predetermined angle (θ4) with respect to the line connecting the lower left coordinate 41(0,Y) and the lower right coordinate 42(X,Y) of the base image data (4), as shown in the figure. In this case, if the coordinates of the feature region (4γ0) located on the left are 4γ0(x1,y1) and the coordinates of the feature region (4γ1) located on the right are 4γ1(x2,y2), then θ4 = tan -1 The angle (θ4) can be found using the equation (y2-y1 / x2-x1).

[0081] Next, we calculate the distance (4γk) between feature parts. The distance (4γk) between feature parts is 4γk = √((x² - x¹) 2 +(y2-y1) 2 It can be calculated using ).

[0082] Next, the angle (θ4) obtained in (S05) is compared with the reference angle, which is one of the correction data, to determine if it is a specified value (S06). In this embodiment, the reference angle stored in the correction data becomes the specified value. If the specified value is 0 degrees, the base image data (4) is tilted by an angle (θ4). In that case, since the angle (θ4) of the base image data (4) does not match the specified value, the next process (S07) is performed. If they match, the next process (S07) is omitted.

[0083] If the predetermined angle (θ4) of the base image data (4) does not match the specified value, the tilt of the base image data (4) is corrected (S07). In this embodiment, the angle (θ4) formed by the lower edge of the base image data (4) and the virtual line (i) can be corrected using an affine transform. Figure 22 is a diagram of the base image data (4) shown in Figure 21 after angle correction. When angle correction is performed, the image size of the base image data (4) increases according to 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 base image data (4).

[0084] Next, the reference distance (5k), which is one of the correction data, is compared with the distance between feature parts (4γk) of the base image data (4) to determine if they match (S08). If they do not match, the process proceeds to the next step (S09); if they do match, the next step (S09) is omitted and the preprocessing step (K20) is terminated.

[0085] The reference distance (5k), which is one of the correction data, is compared with the distance between feature parts (4γk) of the base image data (4). If they do not match, the base image data (4) is enlarged or reduced so that the distance between feature parts (4γk) of the base image data (4) becomes equal to the reference distance (5k). When the distance between feature parts (4γk) is recalculated from units such as mm or cm to pixels, if a fractional value occurs, it is best to make it an integer value.

[0086] By performing the above process, the pre-processing step (K20) is completed.

[0087] Furthermore, the base image data (4) can also be corrected using spatial frequency image data (17) obtained by converting it into a spatial frequency image through spatial frequency transformation. This method will be explained in detail in the preprocessing step (K21) of the second embodiment described later.

[0088] (Image display process) Figure 23(a) shows the first latent image element group data (1), the second latent image element group data (2), and the third latent image element group data (3) that constitute the base image element section (4α) in the base image data (4). Figure 24 shows the state in which the first latent image pattern data (1'), the second latent image pattern data (2'), and the third latent image pattern data (3'), which are generated by dividing and enlarging the base image data (4) containing these latent image element group data (1, 2, 3), are displayed sequentially on the display unit (T05) of the latent image reading device (T). Thus, the image display step (K30) is a step of displaying multiple latent image pattern data (1', 2', 3') sequentially on the display unit (T05). Figure 25 is a flowchart of the image display step (K30). The details of the image display step (K30) will be explained below using this flowchart.

[0089] First, display image data (6) is created (S10), which is image data with the same X (pixel) × Y (pixel) size as the base image data (4). Display image data (6) is image data obtained by dividing the base image element part (4α) of the base image data (4) and applying an enlargement process, and then arranging the divided image data (7), which will be described later, according to the flow of the image display process (K30) shown in Figure 25.

[0090] Next, the total number (N) of the multiple latent image element data (1, 2, 3) that constitute the base image element (4α) is obtained (S11). One method for obtaining the total number (N) of the multiple latent image element data (1, 2, 3) is to use a pattern matching method. For example, a reference image that serves as a basis for identifying the base image element (4α) in the base image data (4) is stored in the storage unit (T06) in advance, and the base image element (4α) can be identified by performing pattern matching on the base image data (4) using that reference image. Then, by associating the information of the total number (N) of the latent image element data (1, 2, 3) and the information of the base image element (4α) with the reference image for identifying the base image element (4α) and storing them in the storage unit (T06) in advance, the total number (N) of the latent image element data (1, 2, 3) can be obtained.

[0091] As shown in Figure 23(a), the first to third latent image element data (1, 2, 3) constituting the base image element section (4α) in the base image data (4) correspond to the first to third latent image element groups (1a, 2a, 3a) shown in Figure 2, respectively. Therefore, the total number (N) of multiple latent image element groups (1a, 2a, 3a) constituting the latent image (A1) is the same as the total number of multiple latent image element data (1, 2, 3). In this embodiment, since the base image element section (4α) is composed of the first latent image element data (1), the second latent image element data (2), and the third latent image element data (3), the total number (N) of multiple latent image data (1, 2, 3) is 3.

[0092] Next, the latent image element pitch (p) of the multiple latent image element data (1-1, 2-1, ..., 3-n) that constitute the latent image element group data (1, 2, 3) is obtained (S12). Figure 23(b) is an enlarged view of a part of the base image element section (4α). As shown in the figure, the base image element section (4α) is composed of multiple latent image element data (1-1, 2-1, ..., 3-n) arranged in order with a latent image element pitch (p). This latent image element pitch (p) is obtained by dividing the virtual lens pitch (Lp) by the total number (N) of the multiple latent image element groups. In this embodiment, the virtual lens pitch (Lp) has already been obtained in the preprocessing step (K20). If the virtual lens pitch (Lp) obtained in the preprocessing step (K20) is 12 pixels, then 12 ÷ 3 = 4, and the latent image element pitch (p) is 4 pixels.

[0093] Next, the system sets which latent image element data (1, 2, 3) to display, and also sets the coordinates t(x3, y3) of the cropping position (t) where the image will be divided in the image division process described later (S13). In this embodiment, since the first latent image element data (1) is to be displayed, the variable "m" is set as a value that determines which latent pattern data (1') to display, and since the first latent pattern data is to be displayed, its setting is set to 1. When setting the coordinates t(x3, y3) of the cropping position (t) where the base image data (4) is divided, the cropping position (t) is usually set to the upper left point 40(0,0) shown in Figure 23(a) of the base image data (4). However, it is not limited to this, and any point can be set as the cropping position (t). In this embodiment, for the sake of clarity, the position of the cropping position (t) shown in Figure 23(b) will be described as t(j,0).

[0094] Next, when dividing the base image data (4), a counter for counting which image the divided image will be is set (S14). In the present embodiment, when dividing the base image data (4), a variable "n" is prepared as a counter for counting which image the divided image will be, and the set value is set to 1 in order to cut out the first divided image data (7). Note that this step is provided for the purpose of explaining the present invention and is not essential.

[0095] Next, from the cutout position (t) of the base image data (4), divided image data (7 m-n ) having a horizontal width (width in the X-axis direction) of the latent image element pitch (p) pixels and a vertical width (width in the Y-axis direction) of Y pixels is acquired (S15). In the present embodiment, the divided image data (7 1-1 ) divided from the base image element portion (4α) shown in FIG. 23(b) is acquired. FIG. 26(a) is a diagram showing the divided image data (7 1-1 ).

[0096] Next, the width of the divided image data (7 1-1 ) is enlarged in the X-axis direction so as to have a numerical value of the virtual lens pitch (Lp) (S16). FIG. 26(b) is a diagram showing the enlarged divided image data (7 1-1 ). Although it is preferable to perform the enlargement process so that the discriminator can clearly visually recognize the first latent image pattern data (1'), this process is not essential and may be omitted. However, when the enlargement process is not performed, the latent image element group data (1, 2, 3) shown in FIG. 23 will be displayed on the display unit (T05) as the display image data (6) described later. In that case, the discriminator can discriminate and visually recognize the latent image (cherry blossom shape) from the shape of the latent image element group data (1, 2, 3) shown in FIG. 23.

[0097] Next, at the coordinate t(j,0) of the display image data (6), the divided image data (7 1-1) is placed (S17). Note that the coordinate t(j,0) is the same coordinate as the base image data (4). Since the image size of the display image data (6) and the base image data (4) is the same X(pixel) × Y(pixel), it is possible to place it at the coordinate where the latent image element data (1-1) existed before division. Figure 26(c) shows the divided image data (7 1-1 This figure shows the state in which the ) is placed on the display image data (6).

[0098] Next, in order to obtain the next segmented image data (7) from the base image data (4), the coordinates t(x3,y3) of the cropping position (t) for dividing the base image data (4) are calculated and set (S18). This calculation can be performed by adding the value of the virtual lens pitch (Lp) to the X-axis value of the current cropping position (t) coordinates t(x3,y3). In the step of setting the coordinates t(x3,y3) of the cropping position (t) for dividing the image (S13), the coordinates of the first cropping position (t) are t(j,0), so the value is obtained by adding 12 pixels, which is the virtual lens pitch (Lp). Therefore, the coordinates of the cropping position (t) become t(j+Lp,0)=t(j+12,0). Then, in this step, 1 is added to the variable "n" to identify the next segmented data. As a result, it is possible to identify which data of the first latent image element group (1) to divide. As a result, the next data to be split is the latent image element data (1-2) shown in Figure 23(b). However, for processing purposes, it is not necessary to know which data to split, so adding 1 to the variable "n" is not essential.

[0099] Next, it is determined (S19) whether the value obtained by adding the virtual lens pitch (Lp) to the coordinate (x3) set in (S18) is greater than the image size of the base image data (4). Since the size of the base image data (4) is X pixels × Y pixels, the determination is made by comparing the value of the X-axis coordinate of the cropping position (t) (the current value is j + Lp) with the width of the base image data (4), which is X pixels. If the value of the X-axis coordinate of the cropping position coordinate (t) is greater than X pixels, the process proceeds to the next step (S20). If the value of the X-axis coordinate of the cropping position coordinate (t) is less than or equal to the width of the base image data (4), which is X pixels, the process returns to (S15).

[0100] When performing the processing in (S15), the divided image data (7) is such that the width (width in the X-axis direction) is the latent image element pitch (p) pixels and the height (width in the Y-axis direction) is Y pixels. m-n If ) cannot be obtained, segmented image data (7) consisting of the largest width (width in the X-axis direction) that can be obtained m-n The image is obtained and adjusted so that the width is equal to the latent image element pitch (p). For example, if the coordinates of the cropping position (t) are ((width of the base image data (4) (X))-3,0), and the latent image element pitch (p) is set to 4 pixels, then the divided image data of the predetermined size 4 pixels × Y pixels (7 m-n While the value itself cannot be obtained, it can be obtained if it is 3 pixels × Y pixels.

[0101] Also, in (S16), the segmented image data (7 m-n ) is enlarged and divided into display image data (6) and image data (7) in (S17). m-n When ) is placed, the segmented image data (7 m-n ) In some cases the entire image may not fit into the display image data (6), in which case the divided image data (7 m-n The entire image does not need to be placed in the display image data (6). For example, if the coordinates of the cropping position (t) are (X-3,0), then when the scaling process is performed in (S16), the segmented image data (7 m-n ) will have a size of 12 pixels × Y pixels, and the display image data (6) will be divided into divided image data (7m-n ) The entire image data cannot be placed, but the divided image data (7 m-n It is sufficient to place only 3 pixels x Y pixels within that area.

[0102] Figure 27(a) shows that when the process from (S15) to (S19) is repeated, the display image data (6) is divided into segmented image data (7 1-1 , 7 1-2 , 7 1-n Figure 27(b) shows the display image data (6) when the value of the X-axis coordinate t(x,0) of the cropping position (t) exceeds X pixels in (S19), and the first latent image pattern data (1') is created as the display image data (6).

[0103] Next, the first latent image pattern data (1') shown in Figure 27(b) is displayed on the display unit (T05) of the latent image reading device (T) (S20). Figure 24(a) shows the first latent image pattern data (1') displayed on the display unit (T05) of the latent image reading device (T).

[0104] Next, the latent image element data to be displayed next is set (S21). Specifically, 1 is added to the variable "m". The variable "m" is a value that determines which latent image pattern data to display. In the step of setting which latent image element data (1, 2, 3) to display (S13), m=1 was set, so adding 1 to the variable "m" results in m=2. As a result, the latent image element data to be separated from the base image data (4) next can be set to the second latent image element data (2).

[0105] Next, it is determined whether the set variable "m" is greater than the total number (N) of the multiple latent element groups (S22). In (S21), the variable "m" is 2. The total number (N) of the multiple latent element groups is 3. Therefore, the variable "m" is less than the total number (N) of the multiple latent element groups. Thus, the process proceeds to the next step (S23). If the variable "m" is greater than the total number (N) of the multiple latent element group data, it is determined that all of the multiple latent pattern data (1', 2', 3') have been displayed, and the image display step (K30) is terminated.

[0106] Next, if the set variable "m" is less than or equal to the total number (N) of multiple latent element groups, the extraction position (t) of the latent element data (2) to be divided is set (S23). In this embodiment, the second latent element data (2-1), shown in Figure 23, is divided. Therefore, since the initial coordinates of the extraction position shown in Figure 23(b) were t(j,0), the x-coordinate of the extraction position (t) can be obtained by calculating (initial extraction position (j)) + (variable (m) - 1) × latent element pitch (p). Thus, the latent element data pitch is 4 pixels and the variable (m) is 2, so the coordinates t(x3,y3) of the next extraction position (t) become t(j+4,0). After that, the process proceeds to (S14), and thereafter the process from (S14) to (S23) is repeated.

[0107] The above describes a method for reading a latent image (A1) applied to a latent image forming body (S). In this way, by displaying the latent pattern data (1', 2', 3') of the latent image (A1) using a latent image reading device (T), the discriminator can read the latent image based on that image. Furthermore, for example, in this embodiment, if the discriminator knows that the cherry blossom pattern constituting the latent image (A1) appears to rotate, they can use that knowledge to determine authenticity.

[0108] In this embodiment, an example has been described in which the first latent image pattern data (1') to the third latent image pattern data (3') are displayed and the image display process (K30) is completed. However, instead of displaying them only once, the process may be repeated to display the first latent image pattern data (1') to the third latent image pattern data (3'). In that case, the multiple latent image pattern data (1', 2', 3') that have already been created may be saved and displayed on the display unit (T05) at any time. Alternatively, after displaying the third latent image pattern data (3'), the data may be displayed in the reverse order of the above and this may be repeated (in the order of 1', 2', 3', 2', 1').

[0109] Furthermore, in this embodiment, after performing the process of displaying the next latent image pattern data (1') and setting the cropping position (t) (S23), the process is returned to before the process of setting the counter (S14), but it is not limited to this. For example, after performing the process of setting the cropping position (t) (S23), the process may return to the process of acquiring the base image data (4) of the image acquisition process (K10) (S02) as shown in Figure 18. In that case, the process of the image display process (K30) will be performed after the preprocessing process (K20), but among the image display process (K30), the process of setting the latent image element group (1, 2, 3) and the process of setting the cropping position (t) (S13) from the process of creating the display image data (6) (S10) may be omitted as these processes have already been performed once.

[0110] This process allows for real-time image processing. For example, if there is a change in the base image data (4), such as the judge's finger appearing in the image, the change can be reflected. This gives the judge the reassurance that they are seeing an image that has actually been captured, rather than an image that has been pre-captured by the latent image reader (T).

[0111] In addition, in the image display step (K30) of this embodiment, segmented image data (7 m―n After obtaining the image data (6), an enlargement process is performed, and the divided image data (7) is added to the display image data (6).m―n The latent image data (1', 2', 3') is created by arranging the elements, but the first to third latent image data (1', 2', 3') can also be created using a different method. For example, the base image data (4) can be divided into latent element pitch (p) pixels × Y pixels, and all the divided image data (7) that make up the first to third latent image data (1', 2', 3') can be created. m-n After obtaining ) multiple segmented image data (7 m-n From among these, the segmented image data (7 m-n ) may be selected as appropriate to create display image data (6) (1st to 3rd latent image pattern data (1', 2', 3')). In this case, the acquired segmented image data (7 m-n Enlargement processing may also be performed on the image. Even with this method, data similar to the first to third latent image pattern data (1', 2', 3') displayed in the image display process (K30) explained using the flowchart in Figure 25 can be created.

[0112] Note that the divided image data (7) of the displayed image data (6) 1-1 At the coordinate t(j,0) of the cutout position (t) obtained by dividing ) the divided image data (7 1-1 The step of arranging (S17) is described as arranging at the coordinates where the latent image element data (1-1) existed, but it is not limited to that, and when generating the second latent image pattern data (2') and the third latent image pattern data (3'), the segmented image data (7) including the latent image element data (2', 3') shown in Figure 23(b) is also used. 2-1 , 7 3-1 It is also possible to place the ) at the coordinate t(j,0) used when generating the first latent image data (1). In that case, the segmented image data (7) required when generating the second latent image data (2') 2-1 The latent image data (1-1) is positioned at a coordinate shifted by the latent image element pitch (p) to the left of the cutout position (t) during division, where the latent image element data (1-1) is located. Also, the division image data (7) required when generating the third latent image pattern data (3') is positioned. 3-1The latent image element data (1-1) is positioned to the left of the cutout position (t) during the division process, at a coordinate shifted by twice the latent image element pitch (p).

[0113] Alternatively, the latent pattern data (1', 2', 3') formed in the display image data (6) may be converted to any chromatic color and displayed. In this case, the color may be changed for each of the latent pattern data (1', 2', 3').

[0114] For example, the image processing unit (T03) can change the color of pixels in the display image data (6) that have a brightness value below a predetermined value to a predetermined color, and the image processing unit (T03) can be pre-configured to change the predetermined color each time the display image data (6) is generated. For instance, if the predetermined value for brightness is set to 50 or less, and the color of the pixels to be changed to red, blue, and green each time the display image data (6) is generated is set, then if the brightness value of the pixels constituting the latent pattern data (1', 2', 3') is 0, the latent pattern data (1') will be displayed in red, the latent pattern data (2') in blue, and the latent pattern data (3') in green.

[0115] In addition, during the process of displaying the display image data (6) (S20), the base image data (4) may also be displayed on the display unit (T05) at the same time as the display image data (6). Examples of display methods include displaying the display image data (6) overlaid on the base image data (4), or dividing the display unit (T02) into upper and lower areas to create a two-screen display, with the base image data (4) displayed in the upper area and the display image data (6) in the lower area. In this case, the latent image pattern data (1', 2', 3') formed on the display image data (6) may be converted to any chromatic color for display.

[0116] Any chromatic color may be pre-set in the image processing unit (T03), or it may be set by the discriminator as appropriate. One example of a conversion method is to replace the luminance value of pixels that make up the latent image pattern data (1', 2', 3') with the luminance value of the set color. In this case, if the image is grayscale data, it is advisable to change the color setting to RGB or CMYK.

[0117] (Image display process 2) In the image display step (K30) of the latent image reading method described above, even when attempting to display the latent image pattern data (1', 2', 3'), blurred image data may be displayed. This is because the positions of the elements constituting the multiple latent image element group data (1, 2, 3) do not necessarily match the cropping position (t). A concrete example will be explained below.

[0118] As shown in Figure 23(a), the top-left coordinate 40(0,0) is set as the cropping position (t). Then, as shown in Figure 23(a), the leftmost element of the base image element section (4α) is set as the leftmost element constituting the first latent image element group data (1), and if the coordinate of the leftmost part of the base image element section (4α) is (141,60), then the x-coordinate of the leftmost part of the base image element section (4α) is 141 pixels. If the latent image element pitch (p) is set to 4 pixels, then 141 ÷ 4 = 35.25, resulting in a fraction. With these cropping position (t) and latent image element pitch (p) values, the first element constituting the first latent image element group data (1) is divided when the cropping position (t) is t(140,0), and the first divided image data (7 1-1) includes latent image element data (1-1) and latent image element data (2-1). As shown in Figure 28(a), the displayed image data (6) is a first latent image pattern data (1') in which the division position is shifted and multiple latent image element groups (1, 2, 3) are mixed, while Figure 28(b) shows the display image data (6) that should have been displayed. Thus, when performing the image display process (K30), if the position where the base image element part (4α) is placed is not at a position that is an integer multiple of the virtual lens pitch (Lp), the element will be divided in the middle, and the first latent image pattern data (1') as shown in Figure 28(a) will be created. In this case, a problem arises in which the latent image cannot be correctly perceived by the discriminator. Therefore, the image display process (K31) that solves the above problem will be described below.

[0119] Figure 29 shows a detailed flowchart of the image display process (K31). The main difference between this image display process (K31) and the image display process (K30) shown in Figure 25 is the number of latent image pattern data (1', 2', 3') to be displayed. In the image display process (K30) shown in Figure 25, multiple latent image pattern data (1', 2', 3') are created for the total number (N) of multiple latent image element group data (1, 2, 3) that constitute the base image element section (4α), and displayed on the display unit (T05). On the other hand, the image display process (K31), which will be explained in detail below, creates multiple latent image pattern data (1', 2', ..., m') for the number of virtual lens pitch (Lp) values, regardless of the total number (N) of multiple latent image element group data (1, 2, 3), and displays them on the display unit (T05). The image display process (K31) will be explained below using the flowchart in Figure 29. Note that the image acquisition process (K10) and preprocessing process (K20), which precede the image display process (K31), are the same as those already described, so their explanation will be omitted.

[0120] First, display image data (6) is created, which is image data with the same X (pixel) × Y (pixel) size as the base image data (4) (S10).

[0121] Next, the total number (N) of the multiple latent image element data (1, 2, 3) constituting the base image element section (4α) is obtained (S11). The details are the same as the step (S11) for obtaining the total number (N) of latent image elements shown in Figure 25, so they are omitted here.

[0122] Next, the latent image element pitch (p) of the multiple latent image element data (1-1, 2-1, ..., 3-n) that constitute the latent image element group data (1, 2, 3) is obtained (S12). Details are omitted as they are the same as the process described above. In this embodiment, the latent image element pitch (p) is set to 4 pixels and the virtual lens pitch (Lp) is set to 12 pixels.

[0123] Next, the coordinates t(x3,y3) of the cropping position (t) for dividing the base image data (4) are set (S13). In this step, the coordinates t(x3,y3) of the cropping position (t) are set to the value 40(0,0), which is the coordinate of the upper left corner of the base image data (4) as shown in Figure 23(a). Therefore, the coordinates t(x3,y3) of the cropping position (t) become t(0,0).

[0124] Next, a variable "m" is set to indicate which latent pattern data to display (S14). As an initial setting, the first latent pattern data (1') is displayed, so the variable "m" is set to 1. The variable "m" serves as a counter.

[0125] Next, when dividing the base image data (4), a counter is set to count which image is being divided into (S15). In this embodiment, a variable "n" is prepared and its value is set to 1. Note that this step is provided for the purpose of explaining the present invention and is not essential.

[0126] Next, the coordinates of the cutting position (t) of the base image data (4) are set to t(0,0), and the divided image data (7 m-nThe process from acquiring the first latent image data (1') (S16) to displaying the first latent image data (1') on the display unit (T05) (S20) is carried out. This process is the same as the divided image data (7) of the image display process (K30) explained with reference to Figure 25. m-n The process from acquiring the first latent image data (1') (S16) to displaying the first latent image data (1') on the display unit (T05) (S20) is the same as described above, so the explanation is omitted.

[0127] At this time, the displayed first latent pattern data (1') may not necessarily be an image similar to the first latent element group (1), the second latent element group (2), and the third latent element group (3) shown in Figure 23(a), and an unclear image may be created, but this is not a problem. An unclear image is an image in which the latent elements of any two of the first latent element group (1), the second latent element group (2), and the third latent element group (3) are mixed, and is the first latent pattern data (1') shown in Figure 28(a).

[0128] Next, we add 1 to the variable "m" (S22). As mentioned above, the variable "m" indicates which latent pattern data to display. Since the first latent pattern data (1') has been displayed, in order to display the next, second latent pattern data (2'), we add 1 to the current value of the variable "m" to make the value of the variable "m" 2.

[0129] Next, the value of the variable "m" is compared to the value of the virtual lens pitch (Lp) (S23). In this embodiment, the virtual lens pitch (Lp) is "12" and the value of the variable "m" is "2", so the value of the variable "m" is less than or equal to the value of the virtual lens pitch (Lp). In that case, the process proceeds to setting the next cropping position (t) (S24). If the value of the variable "m" exceeds the virtual lens pitch (Lp), the image display process (K31) is terminated.

[0130] Next, if the value of the variable "m" is less than or equal to the value of the virtual lens pitch (Lp), the cropping position (t) for creating the mth latent image pattern data (m') is set (S24). Specifically, the x-coordinate of the cropping position (t) is the value of the variable "m" minus 1. Therefore, in this embodiment, since the variable "m" is 2, the coordinates of the cropping position (t) are t(1,0).

[0131] Following the flowchart shown in Figure 29, the 12 latent image pattern data (1', 2', ..., 12') will ultimately be displayed sequentially on the display unit (T05). In this way, by creating the same number of latent image pattern data (1', 2', ..., 12') as the value of the virtual lens pitch (Lp), at least one of the created latent image pattern data (1', 2', ..., 12') will be similar to the first to third latent image element group data (1', 2', 3') shown in Figure 24, allowing the discriminator to correctly acquire the latent image.

[0132] Furthermore, in the image display step (K31) described in the flowchart of Figure 29, the same number of latent image pattern data (1', 2', ..., 12') as the value of the virtual lens pitch (Lp) are created and displayed sequentially on the display unit (T05). As a result, the displayed latent image appears to move more smoothly than in the image display step (K30) described in the flowchart of Figure 25. The latent image reading method including the image display step (K31) can be said to be a latent image reading method that is similar to how a discriminator discriminates a latent image on a latent image forming body (S) using a lenticular lens (14a).

[0133] (Image display process 3) The image display process (K31) described above creates a number of latent image pattern data (1', 2', ..., 12') equal to the number of pixels of the virtual lens pitch (Lp), and any three of these match the first latent image pattern data (1'), the second latent image pattern data (2'), and the third latent image pattern data (3') shown in Figure 24. On the other hand, nine unclear latent image pattern data are created.

[0134] Considering this point, even when the leftmost latent image element of the base image element section (4α), as shown in Figure 23, is not located at an integer multiple of the virtual lens pitch (Lp), it is preferable to display three latent pattern data sets: the first latent pattern data (1'), the second latent pattern data (2'), and the third latent pattern data (3'), which are the same number as the multiple latent image element group data sets (1, 2, 3) that constitute the latent image (A1), as shown in Figure 24. Therefore, regardless of the position of the base image data (4) base image data, an image display step (K32) will be described in which the same number of latent pattern data sets (1', 2', 3') as the multiple latent image element group data sets (1, 2, 3) that constitute the latent image (A1) are displayed. Note that the image acquisition step (K10) and preprocessing step (K20) preceding the image display step (K32) are the same as the steps already described, so their explanation will be omitted.

[0135] Figure 30 is a flowchart showing an overview of the image display process (K32). This image display process (K32) includes a step (S100) for calculating the cropping position (t) and a step (S200) for acquiring and displaying latent pattern data (1', 2', 3') equal to the number of latent element data (1, 2, 3) of the latent image (A1).

[0136] Figures 31 and 32 are flowcharts showing the details of the process (S100) for calculating the cropping position (t) shown in Figure 30. First, display image data (6) is created (S101), which is image data with the same X (pixel) × Y (pixel) size as the base image data (4).

[0137] Next, the total number (N) of the multiple latent image element data (1, 2, 3) constituting the base image element section (4α) is obtained (S102). Details are omitted as this is the same as the step (S11) in the image display step (K30) where the total number (N) of latent image elements is obtained, as explained using Figure 25.

[0138] Next, the latent image element pitch (p) of the multiple latent image element data (1-1, 2-1, ..., 3-n) that constitute the latent image element group data (1, 2, 3) is obtained (S103). Details are omitted as this is the same as the step of obtaining the latent image element pitch (p) (S12) in the image display step (K30) described using Figure 25. In this embodiment, an example is described in which the latent image element pitch (p) is set to 4 pixels and the virtual lens pitch (Lp) is set to 12 pixels.

[0139] Next, the cropping position (t) is set (S104). The coordinates t(x3,y3) of the cropping position (t) are set to the upper left point 40(0,0) in the base image data (4), as shown in Figure 23(a).

[0140] Next, we set the variable "m" (S105). Initially, the variable "m" is set to 1. The variable "m" serves as a counter.

[0141] Next, when dividing the base image data (4), a variable "n" is set to count which image is being divided into (S106). In this embodiment, the value of the variable "n" is set to 1. Note that this step is included for the purpose of explaining the present invention and is not essential.

[0142] Next, the segmented image data (7 m-n The process continues from the step of obtaining (S107) to the step of determining whether the coordinates of the cropping position (t) exceed the image size value of the base image data (4) (S111). For details of this step, see the image display step (K30) explained using Figure 25, which involves dividing the image data (7) into segments with a width of the latent image element pitch (p) pixels and a height of Y pixels. m-nThe process from obtaining the image data (S15) to determining whether the x-coordinate of the cropping position (t) of the base image data (4) is greater than the width (X) of the base image data (S19) is the same and therefore the explanation is omitted. In the process of determining whether the coordinate of the cropping position (t) is greater than the image size value of the base image data (4) (S111), if the value of the X-axis coordinate of the cropping position (t) exceeds the width of the base image data (4), which is X pixels, the process proceeds to the next step (S112). If the value of the X-axis coordinate of the cropping position (t) is less than or equal to the width of the base image data (4), which is X pixels, the process returns to (S106).

[0143] Next, if the value of the X-axis coordinate at the cropping position (t) of the base image data (4) exceeds the width of the base image data (4), X pixels, the histogram of the display image data (6) is saved (S112). The histogram here is a histogram that shows the distribution of how many pixels with each brightness value exist in the image, and is feature data corresponding to the display image data (6) (latent image pattern data). At that time, the coordinates of the cropping position (t) set in the step of setting the cropping position (t) (S104) are also saved in association. In this embodiment, since t(0,0) was set in the step of setting the cropping position (t) (S104), that value is saved.

[0144] Figure 33(a) shows the segmented image data (7 m-n Figure 33(b) shows the display image data (6a) created as a result of the process from acquiring the image data (S107) to determining whether the coordinates of the cropping position (t) exceed the image size value of the base image data (4) (S111), and Figure 33(b) is the histogram (8a) of the display image data (6). This histogram (8a) of the display image data (6) is saved in the storage unit (T06) (S112). The display image data (6) may also be saved, but is not required.

[0145] Next, 1 is added to the variable "m" (S113). In this embodiment, the variable "m" is set as a counter and its value was 1, so in this step (S113), the value of the variable "m" becomes 2.

[0146] Next, it is determined whether the value of the variable "m" is greater than the value of the latent image element pitch (p) (S114). At the stage when the histogram of the first display image data (8a) is saved, the value of the variable "m" is 2 and the latent image element pitch (p) is 4 pixels, so the value of the variable "m" is less than the value of the latent image element pitch (p). In that case, the process proceeds to setting the cropping position (t) (S115). If the value of the variable "m" is greater than the value of the latent image element pitch (p), the process proceeds to obtaining the reference histogram (8') shown in Figure 32 (S116). The reference histogram will be explained later.

[0147] Next, in the step of determining whether the value of variable "m" is greater than the value of the latent image element pitch (p) (S114), if it is determined that the value of variable "m" is less than the value of the latent image element pitch (p), the cropping position (t) is set (S115). The x-coordinate of the cropping position (t) is the value of variable "m" minus 1. Therefore, since the value of variable "m" was 2 at the stage when the histogram (8a) of the first display image data was saved, the coordinates of the cropping position (t) are t(1,0).

[0148] Next, when dividing the base image data (4), the process returns to setting a variable "n" (S106) to count which image the divided image will be, and in the process of determining whether the value of the variable "m" is greater than the value of the latent image element pitch (p) (S114), the process from setting the counter (S106) to setting the cropping position (t) (S115) is repeated until it is determined that the value of the variable "m" is greater than the value of the latent image element pitch (p). As a result, in this embodiment, four histograms (8) of display image data with different cropping positions (t) for every 1 pixel are saved. Figure 33(c) shows the cropping position (t) coordinates from t(1,0) to the divided image data (7 2-1Figure 33(d) is the display image data (6b) generated by extracting ), and Figure 33(d) is the histogram (8b) of the display image data (6b). Also, the segmented image data (7 3-1 The histogram (8c) of the display image data (6c) generated by cutting out ) and the segmented image data (7 4-1 The histogram (8d) of the display image data (6c) generated by extracting (not shown) is saved.

[0149] Next, in the step of determining whether the value of the variable "m" is greater than the value of the latent image element pitch (p) (S114), if it is determined that the value of the counter "m" is greater than the value of the latent image element pitch (p), a reference histogram (8'), which is feature data stored in the memory unit (T06), is obtained (S116), as shown in the flowchart in Figure 32. Figure 34 shows the reference histogram (8'). In this embodiment, the reference histogram (8') is the same as the histogram of the first latent image pattern data (1') shown in Figure 24. However, it is not limited to this, and the histogram of the second latent image pattern data (2') shown in Figure 24 or the histogram of the third latent image pattern data (1') may also be used as the reference histogram (8'). In summary, the reference histogram (8') is feature data corresponding to the reference image.

[0150] Next, the reference histogram (8') is compared with the histograms of multiple display image data (8a, 8b, 8c, 8d), and the degree of agreement for each feature data is calculated (S117). When comparing the reference histogram (8') obtained in (S116), shown in Figure 34, with the histograms (8a, 8b) obtained in (S112), histogram (8b) has the highest degree of agreement with the reference histogram, so histogram (8b) is selected.

[0151] Next, the coordinates of the cropping position (t) stored in association with the histogram (8) that has the highest degree of agreement with the reference histogram (8') are obtained and set (S118). In this embodiment, the coordinates t(1,0) of the cropping position (t) associated with the histogram (8b) shown in Figure 33(d) correspond to this, and these coordinates are set as the cropping position (t). With this step, the process of calculating the cropping position (t) is completed, and the process proceeds to the next step of acquiring and displaying latent image pattern data (S200).

[0152] Figure 35 is a detailed flowchart of the process (S200) for acquiring and displaying latent image pattern data.

[0153] First, the variable "m" is set (S201). The variable "m" indicates which latent pattern data (1', 2', 3') to display, and at the same time, it also serves as a counter. In this embodiment, since the first latent pattern data (1') is to be displayed, the variable "m" is set and its value is set to 1.

[0154] Next, when dividing the base image data (4), a counter is set to count which image is being divided into (S202). In this embodiment, a variable "n" is prepared and set to a value of 1. Note that this step is included for the purpose of explaining the present invention and is not essential.

[0155] Next, the base image data (4) is extracted from the cutting position (t) to create segmented image data (7) whose width is the latent image element pitch (p) pixels and whose height is Y pixels. m-n The crop position (t) is obtained (S203). The crop position (t) at this time is obtained from the crop position (t) stored in association with the histogram (8), and the coordinates set in the setting step (S118) are used. Therefore, in this embodiment, t(1,0) is the coordinate of the crop position.

[0156] From this point onward, the process is the same as the image display process (K30) from (S16) onward as explained using Figure 25, so the explanation will be omitted.

[0157] When this image display process (K32) is performed, even if the leftmost latent image element constituting the first latent image element group data (1), as shown in Figure 23, is not located at an integer multiple of the virtual lens pitch (Lp), it becomes possible to display the same number of first latent image pattern data (1'), second latent image pattern data (2'), and third latent image pattern data (3') as the multiple latent image element group data (1, 2, 3) constituting the latent image (A1), as shown in Figure 24.

[0158] In this image display process (K32), when determining the cropping position (t), histograms (8a, 8b, 8c, 8d) were created and compared with a reference histogram (8') to determine the optimal cropping position (t). However, instead of using histograms (8a, 8b, 8c, 8d), the degree of agreement between the reference image and multiple latent image pattern data can be calculated to determine the optimal cropping position (t).

[0159] In this case, a reference pattern matching image is obtained to serve as the reference image. By pattern matching the reference pattern matching image with multiple display image data (6), in other words, multiple latent image pattern data, the display image data (6) that best matches the reference pattern matching image is selected. The optimal cropping position (t) can then be determined by setting the cropping position (t) associated with that display image data (6) in step (118).

[0160] In this embodiment, the feature point extraction marks (5) attached to the latent image forming body (S) shown in Figure 14 are arranged as two black circles, but their shape is not limited to this.

[0161] Figures 36 and 37 show other examples of feature point extraction marks (5). For example, as shown in Figures 36(a) and (b), the feature point extraction marks (5) may be circles composed of elements, or shapes composed of elements such as a cross as shown in Figure 36(c). Also, as shown in Figure 36(d), there may be different feature point extraction marks (5), such as one being a square and one a triangle, or as shown in Figure 36(e), they may be formed by letters.

[0162] Furthermore, while Figures 36(a) to (e) show the latent image (A1) and the feature point extraction marks (5) arranged on a straight line, as shown in Figure 36(f), the latent image (A1) and the feature point extraction marks (5) do not necessarily have to be aligned on a straight line. In that case, the angle should be corrected so that the angle formed by the feature point extraction marks (5) for angle correction shown in Figure 36(f) becomes the reference angle for the correction data. Also, although the above-described preprocessing step (K20) described an example in which two feature point extraction marks (5) were attached to the latent image forming body (S), it is not limited to this, and marks may be attached to the latent image forming body (S) as appropriate. For example, when acquiring the base image data (4), three feature point extraction marks (5) may be attached to the latent image forming body (S) and used in preprocessing (K20) so that trapezoidal correction, which is one of the distortion corrections, can be performed.

[0163] Furthermore, as shown in Figure 37(a), elements surrounding the latent image (A1), or any elements existing around the latent image (A1) as shown in Figure 37(b), may be used as feature point extraction marks (5). Also, as shown in Figure 37(c), for example, two characteristic points, such as a specific image printed on the substrate, or in this embodiment, the eyes of a human figure, may be used as feature point extraction marks (5). Also, as shown in Figure 37(d), the contour lines of the substrate (13) of the latent image forming body (S) may be edge-extracted and used as feature point extraction marks (5). In addition, in the preprocessing step (K20), by using the feature point extraction marks (5) shown in Figures 37(a) and 37(d), it is possible to perform trapezoidal correction in addition to angle correction and image size correction for the base image data (4).

[0164] In summary, any symbol, character, or arbitrary figure that can be identified as a feature point extraction mark (5) by the latent image reader (T) can be used as a feature point extraction mark (5) regardless of its shape or size.

[0165] Furthermore, if four feature point extraction marks (5) are provided, the acquired base image data (4) can be corrected even if the orientation of the camera (15) of the latent image reader (T) is tilted relative to the latent image forming body (S). In this case, the correction can be performed in the preprocessing step (K20) by performing a perspective transformation using the four feature point extraction marks (5).

[0166] (Second Embodiment) Figure 38 shows a latent image forming body (S) on which only a latent image (A1) consisting of the first latent image element group (1a), the second latent image element group (2a), and the third latent image element group (3a) described in Figures 1 and 2 is placed. In the first embodiment, feature point extraction marks (5), indicated by two black circles, which are used to correct the tilt and size of image data that occurs during shooting, were placed so as to sandwich the latent image (A1). In this embodiment, however, a method for reading the latent image of the latent image forming body (S) when the feature point extraction marks (5) are not placed will be described. The latent image reading device (T) is the same as in the first embodiment, so its description will be omitted.

[0167] (Method for reading latent images) Next, the method for reading the latent image (A1) applied to the latent image forming body (S) will be explained using the flowchart shown in Figure 39.

[0168] Figure 39 is a flowchart showing the steps of the latent image reading method. As shown in Figure 39, the steps proceed in the order of image acquisition (K11), preprocessing (K21), and image display (K30). The basic steps are the same as the latent image reading method described in the first embodiment, but the details of the image acquisition (K11) and preprocessing (K21) steps differ slightly. The details of the image acquisition (K11) and preprocessing (K21) steps will be explained below, and the image display (K30) step will be omitted as it is the same as in the first embodiment.

[0169] (Image acquisition process) The image acquisition step (K11) of the second embodiment acquires the base image data (4) in the same way as the flowchart shown in Figure 18 described in the first embodiment. First, the image acquisition unit (T02) is started (S01). Details have already been explained in the first embodiment, so the explanation will be omitted here.

[0170] Next, the image acquisition unit (T02) is used to acquire the base image data (4), which is image data of the latent image forming body (S) (S02). Details of how to acquire the base image data (4) have already been explained in the first embodiment, regarding the method of taking images using the camera (15) of the latent image reading device (T), so the explanation will be omitted here.

[0171] Figure 40 shows an example of base image data (4) captured by the image acquisition unit (T02). In this embodiment, base image data (4) is acquired, which consists of a base image element (4α) corresponding to the latent image (A1) and a background (4β) other than the base image element (4α).

[0172] Furthermore, Figure 40 shows a guide (16b) on the display unit (T05) to assist in image capture. The discriminator captures the image so that the latent image (A1) fits within the frame of the guide (16b) indicated by the circle. This reduces the tilt of the image during capture, allowing the latent image (A1) to be captured at the desired size.

[0173] (Pre-treatment process) Figure 41 is a detailed flowchart of the pretreatment process (K21). The pretreatment process (K21) will be explained below based on this flowchart.

[0174] First, correction data, which consists of parameters necessary to correct the base image data (4) and is pre-stored in the memory unit (T06), is acquired (S01). The correction data includes a reference angle indicating the appropriate tilt when reading the latent image (A1), a reference size of the latent image (A1), and a virtual lens pitch (Lp) used when dividing the base image data (4) in the image display process (K30) described later.

[0175] Next, the base image data (4) is converted into a spatial frequency image by spatial frequency transformation to obtain spatial frequency image data (17) (S02). The FFT (fast Fourier transform) method is suitable for the spatial frequency image transformation, but other spatial frequency transformations may also be used. Figure 42 shows an example of spatial frequency data (17) obtained by spatial frequency transformation of the base image data (4).

[0176] The spatial frequency image data (17) clearly shows the frequency characteristics of the latent image element group data (1, 2, 3) of the base image data (4) shown in Figure 23. Within this spatial frequency image data (17), the intensity peak (D) of the coordinate closest to the center coordinate is obtained (S03).

[0177] Next, the angle (θ5) between the virtual line (qdL) connecting the center coordinates of the spatial frequency image data (17) and the intensity peak (D) and the reference line (V) is calculated (S04).

[0178] Next, the angle (θ5) between the virtual line (qdL) and the reference line (V) is compared with the previously stored reference angle (S05). If they are different, the angle is corrected so that the angle (θ5) between the virtual line (qdL) and the reference line (V) becomes the reference angle (S06). If the angle (θ5) between the virtual line (qdL) and the reference line (V) is the same as the reference angle, the process proceeds to (S07).

[0179] Next, the size (circumscribed rectangle) of the base image element (4α) is obtained (S07). Figure 43 is a flowchart showing an example of the process for detecting the circumscribed rectangle, and Figure 44 is a diagram showing the binarized image (4') obtained by binarizing the base image data (4). The details of the step (S07) for obtaining the size (circumscribed rectangle) of the base image element (4α) will be explained below using Figures 43 and 44.

[0180] First, a binarized image (4'), which is an image obtained by performing a binarization process on the base image data (4), is acquired (S071). At this time, the threshold for binarization may be predetermined, the classifier may input the threshold value, or an appropriate threshold may be automatically calculated by performing image processing on the base image data (4). Next, as shown in Figure 44, a raster scan is performed sequentially to the right from the origin 40'(0,0) at the left edge of the binarized image (4'), and the X coordinate value (x1) of the first line containing a black pixel detected is obtained. Furthermore, a raster scan is performed sequentially downwards from the origin 40'(0,0) at the left edge of the binarized image (4'), and the Y coordinate value (y1) of the first line containing a black pixel detected is obtained, and a point with XY coordinates (x1,y1) is determined. Then, the raster scan is performed sequentially to the left from the rightmost point 42'(X,Y) of the binarized image (4') to find the X coordinate value (x2) of the first line containing a black pixel detected. Furthermore, the raster scan is performed sequentially upward from the rightmost point 42'(X,Y) of the binarized image (4') to find the Y coordinate value (y2) of the first line containing a black pixel detected, and a point consisting of the above XY coordinate value (x2,y2) is determined (S072). After this process is completed, the coordinates representing the bounding rectangle of the base image element (4α) are calculated. Specifically, the coordinates of the four points that constitute the bounding rectangle of the base image element (4α) are (x1,y1) for the top left, (x2,y1) for the top right, (x1,y2) for the bottom left, and (x2,y2) for the bottom right.

[0181] Next, the size of the base image element (4α) is calculated from the coordinates that constitute the bounding rectangle of the calculated base image element (4α) (S073). As a result of the calculation, the size of the base image element (4α) is (x2 - x1) pixels × (y2 - y1) pixels. This completes the process of obtaining the size of the base image element (4α) (S07).

[0182] Next, the size of the base image element (4α) acquired in (S07) is compared with the reference size acquired in (S01) to determine if they match (S08). If they match, the preprocessing step (K21) is terminated. If they do not match, the base image data (4) is enlarged or reduced so that the size of the base image element (4α) matches the reference size (S09). After that, the preprocessing step (K21) is terminated and the process proceeds to the image display step (K30).

[0183] (Image display process) The image display step (K30) is the same as the image display step (K30) described using the flowchart in Figure 25 in the first embodiment. Therefore, a detailed explanation is omitted. Through this image display step (K30), multiple latent image pattern data (1', 2', 3') can be displayed on the display unit (T05) of the latent image reading device (T), as shown in Figure 24.

[0184] (Third embodiment) In the first and second embodiments, a method for reading the latent image (A1) shown in Figure 1 was described. In the third embodiment, a method for reading the latent image (A2) shown in Figure 4 and the latent image (A3) shown in Figure 5 will be described. The latent image reading device (T) is the same as the one described in the first embodiment, so its description will be omitted.

[0185] Figure 45(a) shows a latent image forming body (S) on which a latent image (A2) and feature point extraction marks (5) are applied to a substrate (13), and Figure 45(b) shows the base image data (4) acquired by photographing the latent image forming body (S) with a latent image reading device (T). This latent image (A2) consists of a group of latent image elements (1a) in which the latent image elements (1a-1) shown in Figure 4(b) are arranged in a first direction (S1) at a constant pitch (L') as shown in Figure 4(a). The latent image elements (1a-1) themselves are obtained by compressing the original image (A2') shown in Figure 4(b) to an arbitrary element width (P) in the first direction (S1). The base image element section (4α) acquired by the latent image reader (T) consists of latent image element data (1-1), which is an image of a latent image element (1a-1), arranged in a first direction (S1) at a constant pitch (L').

[0186] Figure 46 is a flowchart showing an overview of the latent image reading method in this embodiment, and consists of an image acquisition step (K10), a preprocessing step (K20), and an image display step (K33). The image acquisition step (K10) and the preprocessing step (K20) are the same as the steps described using Figures 18 and 20 in the first embodiment, so their explanation will be omitted. The image display step (K33) of the third embodiment will be explained using the detailed flowchart shown in Figure 47. In this embodiment, if the arrangement pitch (p) of the latent image element data (1-1) constituting the base image element section (4α) is set to 100%, the virtual lens pitch (Lp) is between 80% and 120%, excluding 100%. Here, an example will be described in which the arrangement pitch (p) of the latent image elements (1-1) is 10 pixels and the virtual lens pitch (Lp) is 12 pixels.

[0187] First, display image data (6) is created, which is image data with the same X (pixel) × Y (pixel) size as the base image data (4) (S10).

[0188] Next, the coordinates t(x3,y3) of the cropping position (t) for dividing the base image data (4) are set (S11). In this example, if the upper left corner of the base image data (4) is set as the origin (0,0), the coordinates of the cropping position (t) are set as t(0,0).

[0189] Next, a variable "m" is set to indicate which latent pattern data to display (S12). As an initial setting, the first latent pattern data (1') is to be displayed, so the variable "m" is set to 1. The variable "m" serves as a counter.

[0190] Next, when dividing the base image data (4), a counter is set to count which image is being divided into (S13). In this embodiment, a variable "n" is prepared and its value is set to 1. Note that this step is provided for the purpose of explaining the present invention and is not essential.

[0191] Next, the base image data (4) is extracted from the cutting position (t), and the divided image data (7 m-n ) is obtained (S14). At this time, for example, divided image data (7 m-n ) is obtained. Segmented image data of the embodiment (7 m-n In the process of acquiring (S14) the image data, the width of the cutout in the X-axis direction does not necessarily have to be 1 pixel. When displaying the display image data (6) (latent image pattern data (1')) described later, the segmented image data (7 m-nThe width of the cropped area in the X-axis direction can be set appropriately, as long as it does not exceed the virtual lens pitch (Lp). On the other hand, if the cropping width in the X-axis direction is too wide, noise will be included in the latent image pattern data (1'), and a blurred original image (A2') will be reproduced, making it impossible for the discriminator to see the original image (A2'). Therefore, it is preferable that the cropping width in the X-axis direction be one-third or less of the virtual lens pitch (Lp). More preferably, it is preferable that it be one-quarter or less of the virtual lens pitch (Lp), so that the original image (A2') can be clearly seen by the discriminator as latent image pattern data (1').

[0192] Next, the segmented image data (7 m-n The process continues from the step of enlarging the image (S15) to the step of comparing whether the value of the variable "m" is greater than the value of the virtual lens pitch (Lp) (S21). This step is the same as the steps shown in (S17) to (S23) in Figure 29 in the first embodiment, so its explanation is omitted. In this embodiment, the original image (A2') shown in Figure 4 is reproduced on the display unit (T05) by the step of displaying the display image data (6) (S19).

[0193] Next, in step (S21), the value of the variable "m" is compared to the value of the virtual lens pitch (Lp). If the value of the variable "m" is less than or equal to the virtual lens pitch (Lp), the cropping position (t) is set (S22). At this time, the x-coordinate of the cropping position (t) is set to the value of the variable "m" minus 1, and the y-coordinate is set to 0. Therefore, in this example, since the variable "m" was set to 2 in (S20), 2-1=1, so the cropping position (t) becomes t(1,0).

[0194] When the image display process (K33) is performed according to the flowchart shown in Figure 47, the original image (A2') shown in Figure 4(b) is displayed on the display unit (T05) so that it appears to be moving in the first direction (S1).

[0195] In this embodiment, the method for reading the latent image of the latent image (A2) was described, but the latent image of the latent image (A3) shown in Figure 5 can also be made to manifest by performing a similar process. However, when reconstructing the original image (A3') from the latent image (A3), the virtual lens pitch (Lp) used is determined by performing the process shown in Figure 47 under the condition that the pitch (p) of the latent image element data (1a-1, 1a-2, ..., 1a-n) constituting the base image element portion (4α) in the base image data (4) acquired from the latent image (A3) is equal to the virtual lens pitch (Lp).

[0196] (Fourth embodiment) In the fourth embodiment, a method for reading the latent images of the latent image (A4) shown in Figure 6 and the latent image (A5) shown in Figure 9 will be described. Note that the latent image reading device (T) has the same configuration as described in the first embodiment, so its description will be omitted.

[0197] Figure 48(a) shows a latent image forming body (S) on which a latent image (A5) has been applied to a substrate (13), and Figure 48(b) shows the base image data (4) acquired by photographing the latent image forming body (S) with a latent image reading device (T). This latent image (A5) consists of a group of latent image elements (41a) in which latent image elements (41a-1-1, ..., 41a-mn) are arranged at a constant pitch (L') in a first direction (S1) and a second direction (S2), obtained by dividing and compressing the original image (A5') shown in Figure 9(b) from two directions to have arbitrary element widths (P). The latent image element group data (41) of the base image element section (4α) acquired by the latent image reading device (T) consists of latent image element data (41-1, ..., 4m-n) arranged in a first direction (S1) and a second direction (S2) at a constant pitch (L').

[0198] Figure 49 is a flowchart showing an overview of the latent image reading method in this embodiment, and consists of an image acquisition step (K10), a preprocessing step (K22), and an image display step (K34). The image acquisition step (K10) is the same as the step described using Figure 18 in the first embodiment, so its explanation will be omitted. Figure 50 is a detailed flowchart of the preprocessing step (K22) in the fourth embodiment. The preprocessing step (K22) will be explained here using this flowchart.

[0199] (Pre-treatment process) First, the base image data (4) is converted into a spatial frequency image by spatial frequency transformation to obtain spatial frequency image data (17) (S01). Details of the spatial frequency image data (17) were explained in the preprocessing step (K21) of the second embodiment, so the explanation is omitted here.

[0200] Next, the intensity peak (D) of the coordinate closest to the center coordinate is obtained from the spatial frequency image data (17) (S02).

[0201] Next, the angle (θ5) between the virtual line (qdL) connecting the center coordinates of the spatial frequency image data (17) and the intensity peak (D) and the reference line (V) is calculated (S03).

[0202] Next, the angle (θ5) between the virtual line (qdL) and the reference line (V) is compared with the previously stored reference angle (S04). If they are different, the angle is corrected so that the angle (θ5) between the virtual line (qdL) and the reference line (V) becomes the reference angle (S05). If the angle (θ5) between the virtual line (qdL) and the reference line (V) is the same as the reference angle, the process proceeds to (S06).

[0203] Next, we obtain the length of the virtual line (qdL) (S06). The virtual line (qdL) can be determined from the coordinates of the intensity peak (D).

[0204] Next, the virtual lens pitch (Lp) is set based on the virtual line (qdL) (S07). The virtual line (qdL) corresponds to the pitch (p) between latent image element data shown in Figure 48. Therefore, for the latent image image (A5) shown in Figure 48(a), the length of the virtual line (qdL) is set directly as the virtual lens pitch (Lp). Also, when reading the latent image image (A4) shown in Figure 6, if the length of the virtual line (qdL) is set to 100%, the virtual lens pitch (Lp) is set to 80% or more and 120% or less, excluding 100%. As an example of the embodiment, an example in which the arrangement pitch (p) of the latent image element group data (41) is set to 10 pixels and the virtual lens pitch (Lp) is set to 10 pixels will be described.

[0205] The above is the pre-processing step (K22). This pre-processing step (K22) can also be used in the latent image reading method when using the image display step (K31) described in the first embodiment, and in the latent image reading method described in the third embodiment.

[0206] (Image display process) Figure 51 is a detailed flowchart of the image display process (K34). This flowchart will be used to explain the image display process (K34).

[0207] First, display image data (6) is created, which is image data with the same X (pixel) × Y (pixel) size as the base image data (4) (S10).

[0208] Next, the cropping position (t) is set (S11). The cropping position (t) may be set in advance, or it may be specified by the classifier. For example, if it is set in advance, the coordinates of the center of the base image data (4) may be set as the initial cropping position (t), or the coordinates of the upper left corner of the base image data (4) may be set as the cropping position (t). If the classifier specifies it, an input screen for specifying the coordinates of the cropping position (t) may be displayed on the display unit (T05), and the classifier may input the coordinates of the cropping position (t), or the classifier may input the coordinates of the cropping position (t) by touching the base image data (4) displayed on the display unit (T05).

[0209] Figure 52 shows the latent image element data (41-1, ..., 43-3) located within the area enclosed by the thick frame in the base image data (4) shown in Figure 48(b). In one example of this embodiment, we will explain the case where the coordinates of the upper left corner of the base image element (4α) shown in Figure 52 are set to the cropping position t(0,0).

[0210] Next, the variable "m" is set (S12). Initially, the variable "m" is set to 1. The variable "m" serves as a counter. Note that this step is included for the purpose of explaining the present invention and is not essential.

[0211] Next, when dividing the base image data (4), a counter is set to count which image is being divided into (S13). In this embodiment, a variable "n" is prepared and its value is set to 1. Note that this step is provided for the purpose of explaining the present invention and is not essential.

[0212] Next, the divided image data (7) is obtained by dividing the base image data (4) into predetermined sizes from the cutting position (t). m-n ) is obtained (S14). At this time, for example, divided image data (7 m-n ) is obtained. Then, the latent image pixel data (41-1-1-1) that constitutes the latent image element data (41-1) shown in Figure 52 is divided into segmented image data (7 1-1 The case where ) is used will be explained. Note that the segmented image data of the embodiment (7 m-n In the process of acquiring (S14), the width to be cut in the X-axis direction and the width to be cut in the Y-axis direction do not necessarily have to be 1 pixel, and when displaying the display image data (6) (latent image pattern data (1')) described later, the original image (A5') shown in Figure 9(b) can be reproduced as segmented image data (7 m-nThe widths that can be cropped in the X-axis direction and the Y-axis direction can be set appropriately as long as they do not exceed the virtual lens pitch (Lp). On the other hand, if the widths that can be cropped in the X-axis direction and the Y-axis direction are too wide, noise will be included in the latent image pattern data (1'), and a blurred original image (A5') will be reproduced, making it impossible for the discriminator to see the original image (A5'). Therefore, it is preferable that the cropping width in the X-axis direction and the cropping width in the Y-axis direction be one-third or less of the virtual lens pitch (Lp). More preferably, it is preferable that it be one-quarter or less of the virtual lens pitch (Lp), so that the original image (A2') can be clearly seen by the discriminator as latent image pattern data (1').

[0213] Next, the segmented image data (7 m-n The process of enlarging the divided image data (7 1-1 The image is enlarged in the X-axis and Y-axis directions to match the value of the virtual lens pitch (Lp). As an example illustrating this embodiment, the segmented image data (7 1-1 ) has a size of 1 pixel × 1 pixel, and the virtual lens pitch (Lp) is 10 pixels, therefore the segmented image data (7 1-1 This process enlarges the image to a size of 10 pixels x 10 pixels. Note that this process is not mandatory and can be omitted.

[0214] Next, the divided image data (7) of the display image data (6) 1-1 The divided image data (7 1-1 ) is placed (S16). Note that the coordinates t(x,y) are the same as those of the base image data (4). Since the image size of the display image data (6) and the base image data (4) are the same X(pixel) × Y(pixel), it is possible to place it at t(0,0) where the latent image pixel data (41-1-1-1) existed before division.

[0215] Next, in order to obtain the following divided image data (7) from the base image data (4), the coordinates t(x3, y3) of the cut-out position (t) for dividing the base image data (4) are calculated and determined (S17). This calculation can be performed by adding the value of the virtual lens pitch (Lp) to the value in the X-axis direction of the coordinates t(x3, y3) of the current cut-out position (t). In the step (S11) of setting the coordinates t(x3, y3) of the cut-out position (t) for dividing the image, since the coordinates of the first cut-out position (t) are t(0, 0), the value obtained by adding the virtual lens pitch (Lp), which is 10 pixels, is used. Therefore, the coordinates of the cut-out position (t) are t(0 + Lp, 0) = t(10, 0). As a result, next, the divided image data (7 1-2 ) is generated in this process. And in this step, 1 is added to the variable "n" to specify the following divided image data (7).

[0216] Next, it is determined whether the value obtained by adding the virtual lens pitch (Lp) to the coordinate (x3) set in (S17) is greater than the value of the image size of the base image data (4) (S18). Since the size of the base image data (4) is Xpixel × Ypixel, it is determined by comparing the value of the coordinate in the X-axis direction of the cut-out position (t) (the current value is 10) with the value of Xpixel, which is the horizontal width of the base image data (4). If the value of the coordinate in the X-axis direction of the cut-out position (t) is greater than Xpixel, the process proceeds to the next process (S19). If the value of the coordinate in the X-axis direction of the cut-out position (t) is less than or equal to Xpixel, which is the horizontal width of the base image data (4), the process returns to the process in (S14).

[0217] Next, in the process of (S18), when the value of the coordinate in the X-axis direction of the cut-out position (t) is greater than Xpixel, the cut-out position (t) is set (S19). Specifically, The value is obtained by adding the virtual lens pitch (Lp) to the value of the Y coordinate of the coordinates t(x3, y3) of the cutout position (t) initially set in (S11). Therefore, in this example, since the cutout position (t) set in (S11) is t(0, 0), the cutout position (t) set in (S19) is t(0, 10).

[0218] Next, it is determined whether the value obtained by adding the virtual lens pitch (Lp) to the coordinate (y3) set by (S19) is greater than the value of the image size of the base image data (4) (S20). Since the size of the base image data (4) is Xpixel × Ypixel, it is determined by comparing the value of the coordinate of the cutout position (t) in the Y-axis direction (the current value is 10) with the value of Ypixel, which is the vertical dimension of the base image data (4). If the value of the coordinate of the cutout position (t) in the Y-axis direction is greater than Ypixel, the process proceeds to the next process (S21). If the value of the coordinate of the cutout position (t) in the Y-axis direction is less than or equal to Ypixel, which is the vertical dimension of the base image data (4), the process returns to the process of (S14). At that time, 1 is added to the variable "m".

[0219] Next, when the value of the coordinate (y3) of the cutout position (t) in the Y-axis direction is greater than Ypixel in the process of (S20), the display image data (6) is displayed (S21). At that time, the latent image pattern data (1´) corresponding to the original image (A5´) shown in FIG. 9 is displayed on the display unit (T05).

[0220] Next, the cropping direction (f) is set (S22). This step of setting the cropping direction (f) (S22) is not essential if the latent image (A1) shown in Figure 2, the latent image (A2) shown in Figure 4(a), or the latent image (A3) shown in Figure 5(a) is formed by dividing the original image (A1', A2', A3') in one direction, as described in the first and second embodiments, because there is only one cropping direction, the first direction (S1). However, as explained in the background art, when the lens array (14b) is stacked on the latent image images (A4, A5) in this embodiment, changing the viewer's viewpoint in the up, down, left, right, or diagonal directions, or moving the lens array (14b) in the up, down, left, right, or diagonal directions while it is stacked on the latent image images (A4, A5), has a dynamic effect in which the latent image pattern (1b) shown in Figures 8 and 10 appears to move in the up, down, left, right, or diagonal directions. Therefore, in this embodiment, by setting which direction (up, down, left, or right) the latent image element group data (1) is cut out, the dynamic effect of the final generated latent image pattern data (1') can be reproduced in the same way as the dynamic effect when the lens array (14b) is stacked on the latent image images (A4, A5).

[0221] Figure 53 shows a diagram of Freeman's chaincode. As shown in the figure, symbols (f0) to (f7) are assigned to the eight directions. The process (S22) of setting the cutting direction (f) using these symbols will be explained in detail.

[0222] The cropping direction (f) can be set by input by the discriminator. For example, the direction can be input using the discriminator interface (such as a flick operation) provided as a function of the latent image reading device (T), or by tapping an arrow displayed on the screen, or by using the arrow buttons of an externally connected input device, or any of the general interfaces of the latent image reading device (T). As an example of this embodiment, we will proceed with the explanation assuming that (f0) is input in the step of setting the cropping direction (f) (S22).

[0223] Furthermore, input from the discriminator is not mandatory in this step (S22), and the cropping direction (f) may be set in advance. For example, if the cropping direction (f) is set in advance in the order of the chain codes (f0, f1, f2...f7), the cropping direction (f) will be automatically input according to the predetermined order each time this step (S22) is repeated. In that case, in the image display step (K34), the latent image pattern data (1') will be visible to the discriminator as it rotates counterclockwise according to the order of the pre-set chain codes (f0, f1, f2...f7). Note that the cropping direction (f) is not limited to the direction of the chain codes (f0, f1, f2...f7), but can also be set to any angle, for example, 35 degrees diagonally to the upper right and 10 degrees diagonally to the lower left.

[0224] Next, in step (S22), it is determined whether the cropping direction (f) has been input to the latent image reader (T) (S23). If the cropping direction (f) has been input, the process proceeds to the step of setting the cropping position (S24). If the cropping direction (f) has not been input, the image display step (K34) is terminated.

[0225] Next, if the cutting direction (f) is input, the cutting position is set (S24). In the first loop, the cutting position (t) is set according to the cutting direction (f) input in (S22) from the cutting position (t) set in the step of setting the cutting position (t) (S11). From the second loop onward, the value of the cutting position (t) is set based on the cutting position (t) set in the step of setting the cutting position (S24) of the previous loop. Hereafter, as an example of this embodiment, the step of setting the cutting position in the first loop (S24) will be described.

[0226] In the step of setting the cropping position (t) (S11), the coordinates t(x3,y3) of the cropping position (t) are set to t(0,0) at the upper left corner of the base image element (4α) shown in Figure 52. Then, the cropping direction (f) is set so that when a chain code (f0) is input, the cropping position (t) moves to the right. Furthermore, the segmented image data of the mnth order (7m-n The process (S14) to obtain the segmented image of the mnth (7 m-n Since the data size was 1 pixel × 1 pixel, the cropping position (t) is (1,0) (S24). Then, the process returns to acquiring the segmented image data (S14). The segmented image data (7) acquired in step (S14) is the latent image pixel data (41-1-1-2) shown in Figure 52.

[0227] In the example described above, in the step of setting the cutting direction (f) (S22), An example where chain code (f0) is input is shown, but if chain code (f7) is input, in the step of setting the extraction position (S24), the extraction position t(1,1) for dividing the latent image pixel data (41-1-2-2) shown in Figure 52 is set. In that case, the latent image pattern data (1') displayed in the step of displaying the display image data (6) on the screen (S21) moves diagonally downwards to the right and is visible to the discriminator.

[0228] However, in the step of setting the cutting position (t) (S24), it may not be possible to specify the cutting position depending on the coordinates of the cutting position (t) set in the previous loop and the newly set cutting direction (f). In that case, specify one of the available cutting positions (t). An example is given below.

[0229] First, in the step of setting the cropping position (t) (S11), the coordinates of the cropping position (t) at the upper left corner of the base image data (4) are set to t(0,0), and the subsequent processing is carried out up to (S21). Then, in the step of setting the cropping direction (f) (S22), if a chain code (f4) is input, the coordinates of the cropping position (t) become (-1,0). In this case, since the coordinates to be specified are outside the range of the base image data (4), they cannot be specified as the cropping position (t). In this case, the value of the X-axis coordinate is obtained by adding the value of the virtual lens pitch (Lp) to the numerical value of the X-axis coordinate from the unspecified cropping position t(-1,0). Then, the coordinates of the cropping position (t) become t(9,0).

[0230] As another example, in the step of setting the cropping position (t) (S11), the coordinates of the cropping position (t) at the top left corner of the base image data (4) are set to t(0,0), and processing is carried out according to the flow up to (S21). Subsequently, if a chain code (f3) is input in the step of setting the cropping direction (f) (S22), the coordinates of the cropping position (t) become (-1,-1). In this case, the coordinates would be outside the range of the base image data (4), so they cannot be specified as the cropping position (t). In this case, the values ​​of the X-axis coordinate and the Y-axis coordinate from the unspecified cropping position t(-1,-1) are added to the value of the virtual lens pitch (Lp) to obtain the X-axis and Y-axis coordinates. As a result, the coordinates of the cropping position (t) become t(9,9).

[0231] (Fifth embodiment) Figure 14 shows a latent image forming body (S) on which a latent image (A1) consisting of a first latent image element group (1a), a second latent image element group (2a), and a third latent image element group (3a), as described using Figures 1 and 2, and feature point extraction marks (5) are arranged. In this embodiment, a latent image reading method is described in which a discriminator can reproduce multiple latent image pattern data (1', 2', 3') by moving the latent image reading device (T) in a predetermined direction while photographing the latent image forming body (S) with the latent image reading device (T), or by moving the latent image forming body (S) in a predetermined direction. The predetermined direction is the direction in which multiple latent image pattern data (1', 2', 3') can be expressed from the latent image forming body (S) using the latent image reading device (T), and this direction differs depending on the configuration of the latent image forming body (S). In one example of this embodiment, the predetermined direction refers to the direction in which the latent image elements constituting the first latent image element group (1a) to the third latent image element group (3a) are arranged. The latent image reading device (T) is the same as in the first embodiment, so its description is omitted.

[0232] (Method for reading latent images) Figure 61 is a flowchart showing the steps of the latent image reading method. The method for reading the latent image (A1) applied to the latent image forming body (S) will be explained below using the flowchart shown in Figure 61.

[0233] As shown in Figure 61, the process proceeds in the order of image acquisition (K12), preprocessing (K20), and image display (K35). However, if the preprocessing (K20) is unnecessary, it is possible to omit the preprocessing (K20) step and proceed directly to the image display (K35). In this embodiment, unless a decision is made to stop displaying the display image data (6) (S22), the image display (K35) displays the display image data (6) on the display unit (T05), then returns to the image acquisition (K12), and the process is repeated. The details of each step will be described below.

[0234] (Image acquisition process) Figure 62 is a flowchart showing the image acquisition process (K12). In this embodiment, first, the discriminator operates the latent image reading device (T) to start an application program that executes the latent image reading method of the present invention, which is stored in advance in the memory unit (T06), and starts the image acquisition unit (T02) (S01). Next, the latent image reading device (T) captures an image of the latent image forming body (S) and acquires a video signal (S02). The video signal is updated at a frame rate of, for example, 30 fps (frames per second). Then, the image processing unit (T03) extracts one frame from the acquired video signal and acquires base image data (4), which is a still image (S03).

[0235] FIG. 63 shows the processing flow of the image processing unit (T02). In the latent image reading apparatus (T) of the present embodiment, after the process (S01) of starting the image acquisition unit (T02), the process (S02) of acquiring a video signal is always performed, and the video signal is continuously acquired in real time. After acquiring the base image data (4) in (S03), the processes from (S4) to (S20) corresponding to the processes from the preprocessing step (K20) to the image display step (K35) are performed, the image display data (6) is created, and it is displayed on the display unit (T05) (S21). Thereafter, according to the flowchart shown in FIG. 61, the process returns to the process of the image acquisition step (K12), extracts one frame from the video signal, and acquires the base image data (4).

[0236] In this way, after displaying the image display data (6) based on the base image data (4) of the illustrated frame (A), image processing is not performed on the frames for the time (R) required for image processing, and the next frame to be image processed is frame (D). That is, frames (B) and (C) are not image processed by the image processing unit (T03).

[0237] (Preprocessing step) FIG. 64 is a flowchart showing the preprocessing step (K20) shown in FIG. 61. The preprocessing step (K20) is the same as the preprocessing step (K20) shown in FIG. 20 described in the first embodiment. Therefore, detailed description is omitted. Note that, due to an increase in the process (S02) of acquiring a video signal compared to the first embodiment in the process of the image acquisition step (K12) described in FIG. 62, the flowchart of FIG. 64 is different from the reference numerals used in FIG. 20.

[0238] (Image display step) FIG. 65 is a flowchart including the image display step (K35) shown in FIG. 61 and the process (S22) of determining to stop the display of the display image data. Hereinafter, the image display step (K35) will be described using this flowchart.

[0239] The process of obtaining the latent image element pitch (p) from the process of creating display image data (6) of the same size as the base image data (4) shown in the illustration (S11) (S13) is the same as the processes (S10) to (S12) shown in the flowchart in Figure 25 in the first embodiment, so a detailed explanation is omitted.

[0240] Next, in the image division process described later, the coordinates t(x3,y3) of the cropping position (t) for dividing the image are set (S14). When setting the coordinates t(x3,y3) of the cropping position (t), the cropping position (t) is usually set to the upper left point 40(0,0) as shown in Figure 23(a) in the base image data (4). However, it is not limited to this, and any point can be set as the cropping position (t). In this embodiment, for the sake of clarity, the position of the cropping position (t) shown in Figure 23(b) will be described as t(j,0).

[0241] The process from setting the next variable (S15) to displaying the display image data on the display unit (T05) (S21) is the same as the process from (S14) to (S20) shown in the flowchart of Figure 25 in the first embodiment, so a detailed explanation is omitted.

[0242] In the step (S21) of displaying the display image data (6) on the display unit (T05), the latent image pattern data (1') is displayed on the latent image reading device (T) as the display image data (6) shown in Figure 27(b).

[0243] Next, it is determined whether to stop displaying the image data (S22). This process can be achieved, for example, by displaying a button on the display unit (T05) to terminate the image display process, and having the discriminator operate that button. If the discriminator does not operate the button, it is determined not to stop displaying the image data (6), and in that case, the process returns to the image acquisition process (K12) to acquire the base image data (4) (S03). If the stop button is operated, the latent image reading method is terminated.

[0244] If the process returns to the image acquisition process (K12) after the decision to stop displaying the image data (S22), and then proceeds to the preprocessing process (K20) and the image display process (K35) again, the process of acquiring parameters that have already been acquired can be omitted.

[0245] For example, in the flowchart of the preprocessing step (K20) shown in Figure 64, the step of acquiring the virtual lens pitch (Lp) as correction data (S05) can be omitted, and in the flowchart of the image display step (K35) shown in Figure 65, the steps of acquiring the total number of latent image elements (N) (S12) and acquiring the latent image element pitch (p) (S13) can be omitted.

[0246] Using the latent image reading device (T) that performs the processing described above, the discriminator can reconstruct multiple latent image pattern data (1', 2', 3') by moving the latent image reading device (T) in a predetermined direction while photographing the latent image forming body (S) with the latent image reading device (T), or by moving the latent image forming body (S) in a predetermined direction.

[0247] In one example of this embodiment, image processing is performed on the latent image forming body (S) shown in Figure 14 according to the flow shown in Figure 61. Then, in the step (S14) of determining the cropping position (t) in the image display step (K35), the coordinates of the cropping position (t) are set to t(j,0). Then, the first latent image pattern data (1') shown in Figure 24(a) is displayed as display image data (6) on the latent image reading device (T). Subsequently, for example, if the discriminator moves the shooting position of the latent image reading device (T) by 4 pixels in the x-axis direction, image processing is performed again according to the flow, and the second latent image pattern data (2') shown in Figure 24(b) is displayed.

[0248] In this case, the displayed image data (6) is shifted by 4 pixels from the position where the latent image reader (T) was first displayed. Therefore, although the cropping position (t) in image processing is always constant, it appears to the viewer that cropping started from a position shifted by 4 pixels in the x-axis direction from the cropping position t(j,0).

[0249] This latent image reading method allows for the dynamic manifestation of a latent image from the latent image forming body (S) using a latent image reading device (T) in accordance with the hand movements of the discriminator, thus giving the discriminator a sense of actually seeing the latent image.

[0250] (Sixth Embodiment) In the sixth embodiment, a reading method will be described in which a discriminator captures the latent image (A2) shown in Figure 4 and the latent image (A3) shown in Figure 5 with a latent image reading device (T) and reconstructs the latent image by moving the latent image reading device (T) in a predetermined direction. In this example, the predetermined direction is the first direction (S1) in which the latent image elements (1a-1) constituting the latent image element group (1a) are arranged. The latent image reading device (T) is the same as the one described in the first embodiment, so its description will be omitted.

[0251] Figure 45(a) shows a latent image forming body (S) on which a latent image (A2) and feature point extraction marks (5) are applied to a substrate (13), and Figure 45(b) shows the base image data (4) acquired by photographing the latent image forming body (S) with a latent image reading device (T). This latent image (A2) consists of a group of latent image elements (1a) in which the latent image elements (1a-1) shown in Figure 4(b) are arranged in a first direction (S1) at a constant pitch (L') as shown in Figure 4(a). The latent image elements (1a-1) themselves are obtained by compressing the original image (A2') shown in Figure 4(b) to an arbitrary element width (P) in the first direction (S1). The base image element section (4α) acquired by the latent image reader (T) consists of latent image element data (1-1), which is an image of a latent image element (1a-1), arranged in a first direction (S1) at a constant pitch (L').

[0252] (Method for reading latent images) Figure 66 is a flowchart showing an overview of the latent image reading method in this embodiment, and consists of an image acquisition step (K12), a preprocessing step (K20), and an image display step (K36). As shown in Figure 66, the process proceeds in the order of image acquisition step (K12), preprocessing step (K20), and image display step (K36). However, if the preprocessing step (K20) is unnecessary, it is possible to omit the preprocessing step (K20) and proceed to the image display step (K36). In this embodiment, unless a decision is made to stop displaying the display image data (6) (S22), the display image data (6) is displayed on the display unit (T05) in the image display step (K36), and then the process returns to the image acquisition step (K12) and repeats.

[0253] The following describes each step. The image acquisition step (K12) is the same as the step described using Figure 62 in the fifth embodiment, and the preprocessing step (K20) is also the same as the step described using Figure 64 in the fifth embodiment. Therefore, a detailed explanation is omitted. In this embodiment, if the arrangement pitch (p) of the latent image element data (1-1) constituting the base image element section (4α) shown in Figure 45(b) is set to 100%, the virtual lens pitch (Lp) is between 80% and 120%, excluding 100%. Here, we will describe an example where the arrangement pitch (p) of the latent image elements (1-1) is 10 pixels and the virtual lens pitch (Lp) is 12 pixels.

[0254] (Image display process) Figure 67 is a flowchart that includes the image display process (K36) shown in Figure 66 and the process (S22) for deciding to stop displaying the image data. The image display process (K36) will be explained below using this flowchart.

[0255] The process (S11) of creating display image data (6) of the same size as the base image data (4) shown in Figure 67, and the process (S12) of setting the cropping position (t) are the same processes as (S10) and (S11) explained using Figure 47 in the third embodiment, respectively. Furthermore, the processes from (S13) to (S19) shown in Figure 67 are the same as those from (S13) to (S19) shown in Figure 47, so a detailed explanation is omitted.

[0256] In the step (S19) of displaying the display image data (6) of this embodiment, the original image (A2') shown in Figure 4(b) is displayed on the display unit (T05) as display image data (6).

[0257] Next, it is determined whether to stop displaying the display image data (6) (S20). This process is the same as the process (S22) described using Figure 65 in the fifth embodiment, so a detailed explanation is omitted.

[0258] If the process returns from the decision to stop displaying the image data (S20) to the image acquisition process (K12), and then proceeds again to the preprocessing process (K20) and the image display process (K36), the process of acquiring parameters that have already been acquired can be omitted.

[0259] Using the latent image reading device (T) that performs the processing described above, the discriminator can reconstruct the original image (A2') by moving the latent image reading device (T) in a predetermined direction while capturing the latent image forming body (S) with the latent image reading device (T). At that time, the movement of the original image (A2') shown in Figure 4(b) in the first direction is displayed on the display unit (T05).

[0260] This latent image reading method allows for the dynamic manifestation of a latent image from the latent image forming body (S) using a latent image reading device (T) in accordance with the hand movements of the discriminator, thus giving the discriminator a sense of actually seeing the latent image.

[0261] In this embodiment, a method for reading the latent image of the latent image (A2) has been described, but the latent image of the latent image (A3) shown in Figure 5 can also be made to manifest a latent image by performing a similar process. However, when reconstructing the original image (A3') from the latent image (A3), the virtual lens pitch (Lp) used is determined by performing the process shown in Figure 67 under the condition that the pitch (p) of the latent image element data (1a-1, 1a-2, ..., 1a-n) constituting the base image element portion (4α) in the base image data (4) acquired from the latent image (A3) is equal to the virtual lens pitch (Lp).

[0262] (Seventh Embodiment) In the seventh embodiment, a reading method will be described in which a discriminator captures the latent image (A4) shown in Figure 6 and the latent image (A5) shown in Figure 9 with a latent image reader (T) and reconstructs the latent image by moving the latent image reader (T) in a predetermined direction. In this example, the predetermined direction will be described as the first direction (S1) shown in Figure 48(a). Note that the latent image reader (T) has the same configuration as described in the first embodiment, so its description will be omitted.

[0263] Figure 48(a) shows a latent image forming body (S) on which a latent image (A5) has been applied to a substrate (13), and Figure 48(b) shows the base image data (4) acquired by photographing the latent image forming body (S) with a latent image reading device (T). This latent image (A5) consists of a group of latent image elements (41a) in which latent image elements (41a-1-1, ..., 41a-mn) are arranged at a constant pitch (L') in a first direction (S1) and a second direction (S2), obtained by dividing and compressing the original image (A5') shown in Figure 9(b) from two directions to have arbitrary element widths (P). The latent image element group data (41) of the base image element section (4α) acquired by the latent image reading device (T) consists of latent image element data (41-1, ..., 4m-n) arranged in a first direction (S1) and a second direction (S2) at a constant pitch (L').

[0264] (Method for reading latent images) Figure 68 is a flowchart showing an overview of the latent image reading method in this embodiment, and consists of an image acquisition step (K12), a preprocessing step (K22), and an image display step (K37). As shown in Figure 68, the process proceeds in the order of image acquisition step (K12), preprocessing step (K22), and image display step (K37). However, if the preprocessing step (K22) is unnecessary, it is possible to omit the preprocessing step (K22) and proceed to the image display step (K37). In this embodiment, unless a decision is made to stop displaying the display image data (6) (S22), the display image data (6) is displayed on the display unit (T05) in the image display step (K37), and then the process returns to the image acquisition step (K12) and repeats.

[0265] The following describes each step. The image acquisition step (K12) is the same as the step described using Figure 62 in the fifth embodiment, and the preprocessing step (K22) is the same as the step described using Figure 41 in the fourth embodiment. Therefore, a detailed explanation is omitted. As an example of the embodiment, an example in which the arrangement pitch (p) of the latent image element data (41-1, ..., 4m-n) is 10 pixels and the virtual lens pitch (Lp) is 10 pixels will be described.

[0266] (Image display process) Figure 69 is a flowchart that includes the image display process (K37) shown in Figure 68 and the process of deciding to stop displaying the image data (S22). The image display process (K37) will be explained below using this flowchart.

[0267] The processes from (S10) to (S21) in the image display process (K37) shown in Figure 69 are the same as the processes from (S10) to (S21) in the image display process (K34) shown in Figure 51, so a detailed explanation is omitted.

[0268] In this embodiment, the original image (A5') shown in Figure 9(b) is displayed as display image data (6) on the display unit (T05) of the latent image reading device (T) in the step (S21) of displaying the display image data (6).

[0269] Next, it is determined whether to stop displaying the display image data (6) (S22). This process is the same as the process (S22) described with reference to Figure 65 in the fifth embodiment, so a detailed explanation is omitted.

[0270] Similar to the fifth embodiment, if the process returns to the image acquisition process (K12) after the decision to stop displaying the display image data (S22), and then proceeds again to the preprocessing process (K22) and the image display process (K37), the process of acquiring parameters that have already been acquired can be omitted.

[0271] Using the latent image reading device (T) that performs the processing described above, the discriminator can reconstruct the original image (A5') by moving the latent image reading device (T) in a predetermined direction while capturing the latent image forming body (S) with the latent image reading device (T). At that time, the movement of the original image (A3') shown in Figure 5(a) in the first direction is displayed on the display unit (T05).

[0272] In this embodiment, the method for reading the latent image (A5) shown in Figure 9 has been described, but the latent image (A4) shown in Figure 6 can also be made to manifest a latent image by performing a similar process. However, when reconstructing the original image (A4') from the latent image (A4), the virtual lens pitch (Lp) used is determined by the condition shown in Figure 69, where the pitch (p) of the latent image element data (41-1, 41-2, ..., 4m-n) constituting the base image element part (4α) in the base image data (4) acquired from the latent image (A4) is set to 100%, and the virtual lens pitch (Lp) is set to 80% or more and 120% or less, excluding 100%.

[0273] (Eighth embodiment) This embodiment describes a method for performing a truth / false determination step based on a latent image generated by the latent image reading method of the first to seventh embodiments. Here, we will describe a form in which a truth / false determination step is added to the latent image reading method described in the first embodiment. Figure 54 is a flowchart showing the truth / false determination method in the eighth embodiment. The image acquisition step (K10) to the image display step (K30) shown in Figure 54 are the same as the latent image reading method described in the first embodiment, so we will omit the explanation and describe the new step, the truth / false determination step (K40). The latent image reading device (T) is the same as in the first embodiment, so we will omit the explanation. When performing the latent image reading method, we will describe an example in which the object to be read is a latent image forming body (S) to which the latent image image (A1) shown in Figure 14 has been added.

[0274] Figure 55 is a detailed flowchart of the authenticity determination process (K40). First, discrimination image data (18), which serves as a criterion for determining the authenticity of multiple latent image pattern data (1', 2', 3'), is acquired (S01). The discrimination image data (18) may be stored in the memory unit (T06) in advance. Since the multiple latent image pattern data (1', 2', 3') are created in the image display process (K30), they can be used in this authenticity determination process (K40) by storing each of the latent image pattern data (1', 2', 3') in the memory unit (T06) when they are created. Here, we will explain an example in which the discrimination image data (18) is stored in the memory unit (T06) in advance, and the pattern is the same cherry blossom shape as the original image (A1') shown in Figure 1(b).

[0275] Next, the discriminant image data (18) acquired from the memory unit (T06) is compared with the latent pattern data (1') to determine the degree of agreement. The degree of agreement can be determined by performing pattern matching with the latent pattern data (1') using the discriminant image data (18). Then, it is determined whether the degree of agreement is equal to or greater than a predetermined standard value (S02). Furthermore, if multiple discriminant image data (18) are set for multiple latent pattern data (1', 2', 3'), the degree of agreement with the discriminant image data (18) corresponding to each latent pattern data (1', 2', 3') should be determined and compared with the standard value.

[0276] Next, if the degree of agreement is equal to or greater than a predetermined standard value, the display unit (T05) displays "true" (S03), and the truth / false determination process (K40) is terminated. On the other hand, if the degree of agreement is less than a predetermined standard value, the display unit (T05) displays "false" (S04), and the truth / false determination process (K40) is terminated.

[0277] Furthermore, in the authenticity determination process (K40) (S01), the discrimination image data (18) may be obtained from images such as identification numbers, human figures, or patterns that are assigned to areas in the latent image forming body (S) where the latent image (A1) is not placed. In this case, multiple discrimination image data (18) corresponding to each of the multiple latent pattern data (1', 2', 3') may be obtained.

[0278] Furthermore, the latent image reading method described in the first to seventh embodiments and the authenticity determination method described in the eighth embodiment can be implemented as software executed by a computer and stored on a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a form readable by a computer. Since such processes can be easily carried out by a person with ordinary skill in the art to which the present invention belongs, no further explanation is provided.

[0279] (Ninth Embodiment) This embodiment describes a latent image reading system (30) in which a discriminator uses a smartphone, tablet, or PC (hereinafter referred to as "terminal (31)") to acquire base image data (4) from a latent image forming body (S), then transmits the base image data (4) to a server (32) via a mutually communicable network line, performs image processing on the base image data (4) on the server (32) to generate latent image pattern data (1', 2', 3'), transmits the latent image pattern data (1', 2', 3') from the server (32) to the terminal (31), and displays it on its display unit (T05). In this embodiment, the latent image forming body (S) on which the latent image (A1) is arranged, as shown in Figure 14, will be used as an example.

[0280] Figure 56 shows a latent image reading system (30) according to an embodiment of the present invention. The latent image reading system (30) is configured such that a server (32) and a terminal (31) are connected to each other via a network line (33) so that they can communicate with each other.

[0281] Figure 57 is a block diagram showing the hardware configuration of the server (32), which can be realized by a computer configured by connecting a control unit (T01), an image processing unit (T03), a storage unit (T06), and a communication unit (T07) via a bus or the like. Figure 58 is a block diagram showing the hardware configuration of the terminal (31), which has at least a control unit (T01), an image acquisition unit (T02), an input unit (T04), a display unit (T05), a storage unit (T06), and a communication unit (T07), and optionally an illumination unit (T08), with each part connected by a bus or the like. Detailed explanations of each part of the hardware constituting the terminal (31) and the server (32) are omitted because they are the same as the configuration of the latent image reading device (T) described in the first embodiment.

[0282] Figure 59 is a flowchart showing an overview of the processes performed by the latent image reading system (30). The image acquisition process (S100), the process of transmitting the base image data (4) (S200), the process of receiving the latent image pattern data (S700), and the process of displaying the latent image pattern data (S800) in Figure 59 are processes executed by the control unit (T01) of the terminal (31) by controlling each part of the terminal (31). The process of transmitting the latent image pattern data (1', 2', 3') (S600) from the process of receiving the base image data (S300) is a process executed by the control unit (T01) of the server (32) by controlling each part. Each process will be described below.

[0283] First, the base image data (4) shown in Figure 16 is acquired using the terminal (31) (S100). The details of this step are the same as the image acquisition step (S10) described using Figure 18 in the description of the first embodiment, so the explanation is omitted.

[0284] Next, the terminal (31) uses the communication unit (T07) to transmit the base image data (4) to the server (32) via the network line (33) (S200).

[0285] Next, the server (32) receives the base image data (4) transmitted from the terminal (31) using the communication unit (T07) (S300).

[0286] Next, the server (32) uses its image processing unit (T03) to perform preprocessing to correct the size and tilt of the base image elements (4α) that make up the base image data (4) (S400). This preprocessing is the same as the preprocessing step (S20) described with reference to Figure 20 in the first embodiment, so a detailed explanation is omitted. Figure 22 shows the corrected base image data (4).

[0287] Next, the server (32) uses the image processing unit (T03) to generate latent image pattern data (1', 2', 3') shown in Figure 24 (S500) from the corrected base image data (4). Figure 60 is a detailed flowchart of the process in (S500). The process of generating latent image pattern data (1', 2', 3') in (S500) will be explained below using Figure 60.

[0288] Steps (S510) to (S519), shown in Figure 60, are the same as steps (S10) to (S19) described using Figure 25 in the first embodiment. Therefore, a detailed explanation is omitted.

[0289] If the x-coordinate value of the cropping position (t) is greater than the width (X) value of the base image data (4), the latent image data (1') is saved to the storage unit (T06) of the server (32).

[0290] The setting of the latent image element data (1, 2, 3) to be displayed next (S521) and the setting of the extraction position (t) (S523) are the same as the steps (S21) to (S23) described in Figure 25 in the first embodiment. Therefore, a detailed explanation is omitted.

[0291] When the process of generating this latent pattern data (1', 2', 3') (S500) is completed, the latent pattern data (1', 2', 3') is stored in the storage unit (T06) of the server (32).

[0292] Next, as shown in the flowchart in Figure 59, the latent image pattern data (1', 2', 3') stored in the process of generating the latent image pattern data (S500) is transmitted to the terminal (31) (S600), and the terminal (31) receives the latent image pattern data (1', 2', 3') transmitted from the server (32) (S700).

[0293] Next, the terminal (31) displays the latent image pattern data (1', 2', 3') on the display unit (T05) of the terminal (31).

[0294] In the aforementioned latent image reading system (30), the server (32) generates all of the latent image pattern data (1', 2', 3') and then transmits them all to the terminal (31). However, the system is not limited to this, and each of the latent image pattern data (1', 2', 3') may be transmitted from the server (32) to the terminal (31) as it is generated. Also, although the process (S500) for generating the latent image pattern data (1', 2', 3') is described as generating the latent image pattern data (1', 2', 3') based on the base image data (4) acquired in the image acquisition process (S100), the system is not limited to this. For example, in the process (S500) in which the server (32) generates latent image pattern data (1', 2', 3'), it may generate latent image pattern data (1'), transmit the latent image pattern data (1') from the server (32) to the terminal (31) (S600), and the terminal (31) displays the latent image pattern data (1') on the display unit (T05) (S800), then return to the image acquisition process (S100), acquire the base image data (4) again, and perform the process of generating the next latent image pattern data (2') based on the base image data (4). In that case, the display unit (T05) of the terminal (31) can display the latent image pattern data (1', 2', 3') in real time. Changes in the shooting environment (for example, the judge's finger appearing in the base image data (4), or camera shake) can be reflected, and it is possible to ensure the judge's confidence in the latent image reading system (30). In other words, it can be understood that the process does not simply read the latent image pattern data (1', 2', 3') present on the server (32) based on the base image data (4) captured by the discriminator and display it on the display unit (T05) of the terminal (31). [Explanation of Symbols]

[0295] S Latent Image Maker A1 A2 A3 A4 A5 A6 Latent image A1' A2' A3' A4' A5' A6' Original image 1a First latent image element group, latent image element group 1a-1 Latent Image Element 1a-2 Latent Image Elements 1a-n latent image elements 1a-1-1 Latent Image Element 1a-1-2 Latent Image Elements 1a-1-3 Latent Image Elements 1a-2-1 Latent Image Element 1a-2-2 Latent Image Elements 1a-3-1 Latent Image Element 2a Second latent image element group 2a-1 Latent image element 2a-2 Latent image element 2a-n latent image element 3a Third latent image element group 3a-1 Latent image element 3a-2 Latent image element 3a-n latent image elements O is the center of the latent element group. 1b First latent pattern, latent pattern 2b Second latent pattern 3b Third latent pattern 21 Original image 22a First visible image 22b Second visible image 22c invisible image U Unit 1a' First line element 2a' Second line element 3a' Third line element 4a' The fourth line element 1a'-1 First latent element 1a'-2 The first latent element 1a'-3 The first latent element 1a'-4 The first latent element H discriminator L-lenticular lens pitch L' Pitch of latent element Lp virtual lens pitch P Latent element width p Latent element data pitch N: Total number of data points from multiple latent element sets 1. First latent image element data 2. Second set of latent image element data 3. Third latent image element data 1' First latent pattern data or latent pattern data 2' Second latent pattern data 3' Third latent pattern data 1-1 Latent image element data constituting the first set of latent image elements 1-2 Latent image element data constituting the first set of latent image elements 1-n Latent image element data constituting the first set of latent image elements 2-1 Latent image element data constituting the second set of latent image elements 2-2 Latent image element data constituting the second set of latent image elements 2-n Latent image element data constituting the second set of latent image elements 3-1 Latent image element data constituting the third set of latent image elements 3-2 Latent image element data constituting the third set of latent image elements 3-n Latent image element data constituting the third set of latent image elements 4 Image Data 4' Figure obtained by binarizing the base image data. 4α Base image element 4β background part 4γ, 4γ0, 4γ1 characteristic parts Distance between 4γk feature regions (4γ0, 4γ1) i. Imaginary lines connecting feature regions (4γ0, 4γ1) t Cutting position f cutting direction 5. Feature point extraction marks 6. Displayed Data 7-part image data 8 Histogram 8' Reference Histogram 13 Base material 14a lenticular lens 14b Lens Array 15 Cameras 16a, 16b Guide 17 Spatial frequency image data V, E reference line A virtual line connecting the qdL intensity peak and the inverse spatial distance. D Intensity Peak 18. Discrimination image data 41-1 Latent Image Element Data 42-1 Latent Image Element Data 43-1 Latent Image Element Data 41-2 Latent Image Element Data 42-2 Latent Image Element Data 43-2 Latent Image Element Data 41-3 Latent Image Element Data 42-3 Latent Image Element Data 41 Latent Image Element Set Data 41-1-1-1 Latent image pixel data 41-1-1-2 Latent Image Pixel Data 41-2-1-1 Latent image pixel data 42-1-1-1 Latent image pixel data 30 Latent Image Reading System 31 devices 32 servers 33 Network connections T Latent Image Reader T01 Control Unit T02 Image Acquisition Unit T03 Image Processing Unit T04 Operation section T05 Display section T06 Storage section T07 Communications Department T08 Lighting section K10 K11 Image acquisition process K20 K21 K22 Pre-treatment process K30 K31 K32 K33 K34 K35 K36 K37 Image display process K40 Authenticity determination process

Claims

1. A latent image reading method comprising reading a latent image forming body, in which a latent image is formed on a substrate, in which a latent image is formed by a first latent image element group ..., an m-th latent image element group (where m is an integer of 2 or more), each consisting of a plurality of latent image elements divided in a first direction, arranged sequentially from the first to the mth group without the latent image elements constituting each group overlapping, using a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, The image acquisition process includes a base image data acquisition step in which the image acquisition unit reads the latent image and acquires base image data consisting of the first latent image group, ..., the first latent image group data corresponding to each of the m latent image group, ..., and the m latent image group data, A total number acquisition step to obtain the total number of the aforementioned latent element group, A virtual lens pitch acquisition step is to acquire a virtual lens pitch corresponding to the pitch between each of the latent image element data constituting the latent image element group data, A segmented image data generation step involves dividing the base image data in the direction in which the latent image element data is arranged, with a latent element pitch width that is obtained by dividing the virtual lens pitch by the total number of latent image elements, thereby generating a plurality of segmented image data. A latent pattern data generation step involves sequentially combining multiple segments of the segmented image data, while changing the starting position for combining the segmented image data, at a time interval of the virtual lens pitch, thereby generating multiple latent pattern data. A method for reading a latent image from a latent image forming body, characterized by comprising an image display step which includes an image display step that displays a plurality of the latent image pattern data in the order in which the latent image pattern data were generated.

2. The method for reading a latent image from a latent image forming body according to claim 1, further comprising an enlargement processing step of enlarging a plurality of the divided image data generated by the divided image data generation step.

3. A method for reading a latent image from a latent image forming body according to claim 1 or 2, characterized by having a preprocessing step that includes a preprocessing step of correcting at least one of the size and angle of the base image data acquired by the base image data acquisition step.

4. The method for reading a latent image from a latent image forming body according to claim 1, wherein the division image data generation step includes a cutting position calculation step of calculating an initial cutting position that serves as the starting point for division of the base image data into latent image element data corresponding to the latent image elements, the base image data is divided starting from the cutting position calculated in the cutting position calculation step, and the total number of latent image pattern data generated in the latent image pattern data generation step is equal to the total number of latent image element groups.

5. The step of calculating the cropping position includes obtaining a reference image or feature data corresponding to the reference image for calculating an initial cropping position that will serve as the starting point for division, in order to divide the base image data into each latent image element data corresponding to the latent image element, The steps include obtaining the latent image pattern data having the same number as the latent image element pitch value and the cropping position being different for each 1 pixel, or obtaining feature data corresponding to the latent image pattern data having the same number as the latent image element pitch value and the cropping position being different for each 1 pixel, A step of calculating at least one of the degree of agreement between the reference image and each of the latent pattern data, and the degree of agreement between the feature data corresponding to the reference image and each of the feature data corresponding to the latent pattern data with different cropping positions. The method for reading a latent image from a latent image forming body according to claim 4, characterized in that it comprises the step of setting the initial cutting position to the cutting position associated with the latent image pattern data with the highest degree of agreement or the feature data corresponding to the latent image pattern data.

6. A latent image reading method comprising reading a latent image forming body having a latent image formed in which a plurality of latent image elements obtained by dividing and compressing or compressing an original image in a predetermined direction are arranged at a constant pitch in the predetermined direction, using a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, An image acquisition process comprising a base image acquisition step of acquiring base image data including a base image element portion consisting of latent image element data corresponding to the aforementioned latent image element, The configuration of the latent image element is, (i) If the original image is an element that has been divided and compressed in the predetermined direction, obtain a virtual lens pitch corresponding to the arrangement pitch of the latent image element data, or (ii) If the original image is an element compressed in the predetermined direction, the virtual lens pitch acquisition step acquires the virtual lens pitch corresponding to an arrangement pitch of 80% to 120% excluding 100%, when the arrangement pitch of the latent image element data is set to 100%. A segmented image data generation step involves dividing the base image data into a predetermined width in a predetermined direction for reconstructing the original image, thereby generating a plurality of segmented image data. A latent pattern data generation step involves sequentially combining multiple segments of the segmented image data, while changing the starting position for combining the segmented image data, at a time interval of the virtual lens pitch, thereby generating multiple latent pattern data. A method for reading a latent image from a latent image forming body, characterized by comprising an image display step which includes an image display step that displays a plurality of the latent image pattern data in the order in which the latent image pattern data were generated.

7. The method for reading a latent image from a latent image forming body according to claim 6, further comprising an enlargement processing step of enlarging a plurality of the divided image data generated by the divided image data generation step.

8. A method for reading a latent image from a latent image forming body according to claim 6 or 7, characterized by having a preprocessing step that includes a preprocessing step of correcting at least one of the size and angle of the base image data acquired by the base image data acquisition step.

9. The method for reading a latent image from a latent image forming body according to claim 1 or 6, characterized in that, in the latent image pattern data generation step, the total number of latent image pattern data generated is equal to the number of pixels of the virtual lens pitch.

10. A method for determining the authenticity of a latent image forming body, characterized by comprising the step of determining authenticity using a plurality of latent image pattern data generated using the latent image reading method described in claim 1 or 6.

11. Software for reading latent images, characterized by causing a computer to execute the latent image reading method described in claim 1 or 6.

12. Truth determination software characterized by causing a computer to execute the truth determination method described in claim 10.

13. A latent image reading method comprising reading a latent image forming body, in which a latent image is formed on a substrate, in which a latent image is formed by a first latent image element group ..., an m-th latent image element group (where m is an integer of 2 or more), each consisting of a plurality of latent image elements divided in a first direction, arranged sequentially from the first to the mth group without the latent image elements constituting each group overlapping, using a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, The image acquisition process includes a base image data acquisition step in which the image acquisition unit reads the latent image and acquires base image data consisting of the first latent image group, ..., the first latent image group data corresponding to each of the m latent image group, ..., and the m latent image group data, A total number acquisition step to obtain the total number of the aforementioned latent element group, A virtual lens pitch acquisition step is to acquire a virtual lens pitch corresponding to the pitch between each of the latent image element data constituting the latent image element group data, A segmented image data generation step involves dividing the base image data in the direction in which the latent image element data is arranged, with a latent element pitch width that is obtained by dividing the virtual lens pitch by the total number of latent image elements, thereby generating a plurality of segmented image data. A latent image pattern data generation step involves sequentially combining a plurality of the segmented image data, each at the period of the virtual lens pitch, from the segmented image data to generate latent image pattern data; The image display step includes an image display step that displays the latent image pattern data in the order in which the latent image pattern data was generated, A latent image reading method characterized by performing at least the base image data acquisition step of the image acquisition step, the segmented image data generation step, the latent image pattern data generation step, and the image display step of the image display step while moving either the reading device or the latent image forming body in a predetermined direction.

14. A latent image reading method comprising reading a latent image forming body having a latent image formed in which a plurality of latent image elements obtained by dividing and compressing or compressing an original image in a predetermined direction are arranged at a constant pitch in the predetermined direction, using a reading device that comprises at least an image acquisition unit for acquiring an image, an image processing unit for performing image processing on the acquired image, and a display unit for displaying the image processed image, An image acquisition process comprising a base image acquisition step of acquiring base image data including a base image element portion consisting of latent image element data corresponding to the aforementioned latent image element, The configuration of the latent image element is, (i) If the original image is an element that has been divided and compressed in the predetermined direction, obtain a virtual lens pitch corresponding to the arrangement pitch of the latent image element data, or (ii) If the original image is an element compressed in the predetermined direction, the virtual lens pitch acquisition step acquires the virtual lens pitch corresponding to an arrangement pitch of 80% to 120% excluding 100%, when the arrangement pitch of the latent image element data is set to 100%. A segmented image data generation step involves dividing the base image data into a predetermined width in a predetermined direction for reconstructing the original image, thereby generating a plurality of segmented image data. A latent image pattern data generation step involves sequentially combining a plurality of the segmented image data, each at the period of the virtual lens pitch, from the segmented image data to generate latent image pattern data. The image display step includes an image display step that displays the latent image pattern data in the order in which the latent image pattern data was generated, A latent image reading method characterized by performing at least the base image data acquisition step of the image acquisition step, the segmented image data generation step, the latent image pattern data generation step, and the image display step of the image display step while moving either the reading device or the latent image forming body in a predetermined direction.

15. A method for determining the authenticity of a latent image forming body, characterized by comprising the step of determining authenticity using a plurality of latent image pattern data generated using the latent image reading method described in claim 13 or 14.

16. Software for reading latent images, characterized in that it causes a computer to execute the latent image reading method described in claim 13 or 14.

17. Truth determination software characterized by causing a computer to execute the truth determination method described in claim 15.

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