JPH10166710A - Printing system and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the content of printed matter such as a postcard or a facsimile output sheet from being stealthily seen by a passerby or by another person unawares in public, and also enable the detection of the fact that the content of printed matter is seen by stealth when such a thing really happens by chance. SOLUTION: Of a coded image created by image coding and a share (an image to be superposed on the coded image for restoring an original image), either (suppose that it is the share) of the coded image or the share is turned upside down, and both coded image 11 and reversed share 12 are symmetrically printed on a translucent sheet 10, the formed being located on the upper half and the latter on the lower half of the sheet. Next, the sheet 10 is folded at the symmetrizing line between the code image 11 and the reversed share 12, and then the reversed share 12 will be superposed on the coded image 11 in such a manner that the former is turned upside down to enable the original image to be read.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is employed in an image communication system such as a facsimile or a printing system such as a printer, and an unauthorized person can use the contents of a printed matter (for example, a computer password, an encryption key of an encryption communication device, The present invention relates to a printing method and a printed matter for processing and printing an image in order to make it difficult to see private text and the like.

[0002]

2. Description of the Related Art In order to prevent printed matter such as letters and documents from being stolen by a third party other than a legitimate recipient,
We often sealed prints in envelopes. Also, in order to prevent wiretapping of printed matter issued in large quantities, we often adhered a removable sheet to the printed matter or applied a removable paint to the printed matter. Such a method is well-known in postcards from public institutions and banks, scratch-type speed lottery, and the like.

As a method of preventing an image from being stolen by image processing, a transparent sheet on which an image is printed is sent to a receiver in advance, and the image to be transmitted is encrypted and printed on a printed matter. Was known to send the printed matter. Then, the receiver can read the original image by superimposing the shear on the printed matter, but a third party without the shear cannot read the original image.

FIG. 8 shows the principle of image encryption using a share.
This is briefly explained using. In the following, for convenience of explanation, the image is a binary black-and-white image, but even if it is a multi-valued gray-scale image, image encryption can be performed in the same manner. Also,
In the drawing, a black portion is a portion through which light is hardly transmitted, and a white portion is a portion through which light is easily transmitted. Further, in the figure, solid lines are drawn at equal intervals in the vertical and horizontal directions, which are drawn for convenience in order to emphasize the pixels of the image,
This solid line is not drawn on the actual image.

In FIG. 8, first, noise is added to a white portion of an original image 80 (ie, from white to black) to obtain a noise image 81. The ratio of adding noise is
It depends on how difficult it is to pry, and if you want to completely prevent prying eyes, you can add noise to about half of the white pixels. However, it goes without saying that the original image becomes more difficult to see as the ratio of adding noise increases. Then, the original image 80, the noise image 81, the encrypted image 82, and the share 83 are x-th from the left and y from the top, respectively.
The pixel at the th is G (x, y), N (x,
y), C (x, y) and S (x, y), and when white and black are represented by 0 and 1, respectively, the pixel C of the encrypted image 82
(X, y) and the pixel S (x, y) of the share 83 are determined as follows.

If G (x, y) = 0, N (x, y) =
If 0, C (x, y) = 0 and S (x, y) = 0. If G (x, y) = 0 and N (x, y) = 1, C (x, y) = 1 and S (x, y) = 1. If G (x, y) = 1 and N (x, y) = 1, r is randomly selected and C (x, y) = r, S (x, y) =
1-r. Here, the value of r is 0 or 1.

The cipher image 82 and the shear 83 in FIG. 8 are constructed in accordance with the above-described procedure.
When 3 is superimposed, a noise image 81 is obtained.

[0008] Regarding image encryption, Naoa and Shamir's paper "Visual Cryptography" (M. Naor
andA.Shamir, “Visual Cryptography”, Proc. of Euro
crypt'94 May 1994) has a detailed explanation.

[0009]

Conventionally, methods for sealing a printed matter in an envelope, bonding a releasable sheet to the printed matter, and applying a removable paint to the printed matter are as follows.
Since a material other than the printed material is required and a process for processing is required, there is a problem that the manufacturing cost of the printed material is high. Moreover, in a system in which printed matter is digitized and transmitted, such as a facsimile, it is impossible to perform an operation such as sealing on the transmitting side, and if an operation such as sealing is performed on the receiving side, There has been a problem that a high-cost apparatus for automatically sealing recording paper output from a facsimile on an envelope is required. In the case of facsimile, a method called confidential transmission that prevents eavesdropping by not outputting a received image until a legitimate recipient inputs a password is used (for example, NEC facsimile NEFAX 680/780 / D680 / In order to perform confidential transmission, it was necessary to determine a password with the transmitting party in advance, and there was a problem that the usability was poor.

[0010] In addition, the prevention of eavesdropping by image encryption is as follows.
Although it can be applied to systems like facsimile,
There was a problem that a shear had to be sent in advance. Further, in general, since the printed material is paper while the shear is made of plastic, there is a problem that the printed material is greatly deformed by humidity and the original image cannot be read. Furthermore, although the original image cannot be restored unless the shear is superimposed on the printed matter with high precision, there is a problem that it is difficult to superimpose the shear.

The present invention solves the above problems by devising the superposition of images generated by image encryption, and not only printed matter but also printed matter is digitized and transmitted like facsimile. It is another object of the present invention to prevent an eavesdropping on a system at low cost and without labor for memorizing a password. It is another object of the present invention to easily superimpose images for restoring an encrypted image.

[0012]

According to the printing method of the present invention, at least an image encrypting means (631 in FIG. 6) for generating two images of an encrypted image and a shear image from an image and an image encrypting means. Inverting means (632 in FIG. 6) for inverting one of the encrypted image and the two images vertically and horizontally, and the image which has not been inverted between the encrypted image and the two images. And a print control means (633 in FIG. 6) for printing the image vertically or horizontally symmetrically in accordance with the image inversion direction. Here, as described with reference to FIG. 8, the share is an image to be superimposed on the encrypted image in order to restore the original image.

In the printed matter of the present invention, two images, an encrypted image (11 in FIG. 1) and a shear image (12 in FIG. 1), are placed on a light-transmitting sheet (10 in FIG. 1). The image is printed upside-down or left-right symmetric after being inverted or left-right inverted.

The printed matter of the present invention is provided on a backing paper (5 in FIG. 5).
0) on a light-transmissive sheet (10 in FIG. 5) bonded by a peelable adhesive to the encrypted image (1 in FIG. 5).
The two images 1) and (12 in FIG. 5) are printed vertically or horizontally symmetrically, respectively, after one image is vertically inverted or horizontally inverted.

In order to enhance the effect of preventing prying eyes, the printed matter of the present invention is further printed with an image (20 in FIG. 2) composed of pixels randomly selected adjacent to the encrypted image or the square. Or to facilitate the operation of alignment, the printed matter of the present invention, further,
A folding curve (30 in FIG. 3) may be printed on the symmetry axis between the encrypted image and the shear, or a symbol (40 in FIG. 4) for positioning at a position symmetrical about the symmetry axis between the encrypted image and the shear. )
May be printed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the configuration of an embodiment of the printed matter of the present invention. In the figure, an encrypted image 11 and an inverted shear 12 are printed on a transparent or translucent sheet 10. Here, the inverted shear 12 is obtained by inverting the shear vertically. Therefore, sheet 10
Is folded at the symmetry line between the encrypted image 11 and the inverted shear 12, and the inverted shear 1 is placed on the encrypted image 11.
2 are turned upside down and overlapped, and the original image can be read.
In the figure, the cipher image 11 and the inverted shear 12 are arranged vertically, but if they are arranged left and right, an image obtained by inverting the shear horizontally is printed as the inverted shear 12. do it. In the present invention,
Since the shear is used only once, in the present invention, even if the encrypted image and the shear are exchanged, the effect is not changed at all. In other words, instead of printing by inverting the share, the encrypted image may be printed by inversion.

FIG. 2 is a perspective view showing the structure of a second embodiment of the printed matter of the present invention. In this embodiment, a dummy image 20 is printed at the upper end of the encrypted image 11 in contact with the encrypted image 11 in the printed matter of FIG. The dummy image 20 is an image generated by randomly determining the black and white of each pixel. In order to read the original image without making a fold, the only way to read the dummy image 20 is to overlap the encrypted image 11 and the inverted shear 12 so that the upper end of the encrypted image 11 and the lower end of the inverted shear 12 overlap. Is printed, it becomes more difficult to see the original image without creases in the printed matter. In the figure, the cipher image 11 and the inverted shear 12 are arranged vertically, but if they are arranged left and right, an image obtained by inverting the shear horizontally is printed as the inverted shear 12. Then, the dummy image 20 may be printed in contact with the encrypted image 11 at the right end or the left end of the encrypted image 11, which is farthest from the inverted shear 12. Further, in the present invention, since the shear is used only once, even if the encrypted image and the shear are exchanged in the present invention, the effect is not changed at all. In other words, instead of printing by inverting the share, the encrypted image may be printed by inversion.

FIG. 3 is a perspective view showing the structure of a third embodiment of the printed matter of the present invention. In this embodiment, a symbol 30 (hereinafter referred to as a dotted line) indicating a folding position such as a dotted line is provided at a symmetrical line between the encrypted image 11 and the inverted shear 12 in the printed matter of FIG. , "Bend curve"). By doing so, even if the sheet 10 is thick, for example, a ruler is applied to the fold curve 30, a compass, a cutter, or the like is moved on the fold curve 30 to make a fold, whereby the printed matter can be accurately bent. . In the figure, the encrypted image 1
1 and the oppositely arranged shears 12 are arranged vertically, but if they are arranged left and right, an image obtained by inverting the shears left and right is printed as the inverted shears 12 and the folding curve 30 is encrypted. It may be arranged between the image 11 and the inverted shear 12. Further, in the present invention, since the shear is used only once, even if the encrypted image and the shear are exchanged in the present invention, the effect is not changed at all. In other words, instead of printing by inverting the share, the encrypted image may be printed by inversion.

FIG. 4 is a perspective view showing the structure of a printed matter according to a fourth embodiment of the present invention. In this embodiment, a mark 40 (hereinafter, referred to as an index) for positioning such as a cross mark is printed at a position symmetrical with respect to the folding position in the printed matter of FIG. In this case, the dummy image 20 cannot be printed as shown in FIG. 2 to improve the effect of preventing prying eyes. However, compared to the embodiment shown in FIG. Since the distance can be reduced as much as possible, the degree of freedom in designing printed matter can be increased. In the figure, the cipher image 11 and the inverted shear 12 are arranged vertically, but if they are arranged left and right, an image obtained by inverting the shear horizontally is printed as the inverted shear 12. Just do it. Also, in the present invention, the shear is used only once,
In the present invention, even if the encrypted image is replaced with the share, the effect is not changed at all. In other words, instead of printing by inverting the share, the encrypted image may be printed by inversion.

FIG. 5 is a perspective view showing the structure of a fifth embodiment of the printed matter of the present invention. In this embodiment, the printed matter of FIG. 3 is adhered to a backing sheet 50 using a peelable adhesive. In this way, if the receiver peels off the sheet 10 to the position of the folding curve 30, the printed matter can be accurately bent only by bending the sheet 10 while pulling it lightly. In the figure, the cipher image 11 and the inverted shear 12 are arranged vertically, but if they are arranged left and right, the image obtained by inverting the shear horizontally is referred to as
What is necessary is to print as the inverted shear 12 and to arrange the folding curve 30 between the encryption image 11 and the inverted shear 12. Further, in the present invention, since the shear is used only once, even if the encrypted image and the shear are exchanged in the present invention, the effect is not changed at all. In other words, instead of printing by inverting the share, the encrypted image may be printed by inversion. Further, depending on the application, it is not necessary to print the folding curve as shown in FIG. 1, a dummy image may be printed as shown in FIG. 2, or an index as shown in FIG. May be printed.

If the printed matter of the present invention is copied and the copied printed matter is peeped, the original printed matter can be peeped without creases, but it is difficult to copy as a paint used for printing ( (E.g., a light blue one) makes it harder to sniff through copies.

FIG. 6 is a functional block diagram showing the basic configuration of the printing method of the present invention. As shown in the drawing, the printing method of the present invention includes a control signal input unit 610 for inputting a control signal for designating an encrypted image and a position of a shared image, an image input unit 620 for inputting an image, Input means 6
20 includes a data processing device 630 that performs processing on the image input by the storage device 20, a storage device 640, and a printing device 650 that performs printing on a sheet having optical transparency.

Further, the data processing device 630 performs image encryption on the image input by the image input means 620, and stores the obtained encrypted image and share in the storage device 64.
0, an image encryption unit 631 for storing the image data in the storage unit 640
Is inverted up and down or left and right depending on the control signal input from the control signal input means 610 to generate an inverted share, and stores the inverted share in the storage device 640. Means 632 and a printing device 650 such that the encrypted image stored in the storage device 640 and the inverted share are printed symmetrically in the vertical and horizontal directions, depending on the control signal input from the control signal input means 610. And a print control unit 633 that sends out a control signal and print data.

The print control means 633 also sends to the printing apparatus 650 print data such as a dummy image, a folded curve, and an index, if necessary, in addition to the encrypted image and the inverted share.

FIG. 7 is a flowchart showing the operation of the printing method of the present invention. In the figure, first, an image is input by the image input means 620 (701), the input image is subjected to image encryption, and the obtained encrypted image and share are stored in the storage device 640 (702). Next, a control signal for designating the position of the encrypted image and the shear is input by the control signal input means 610 (703), and the input control signal prints the inverted encrypted image and the shear in a vertically symmetric manner. If so, control is passed to step 705. If the input control signal indicates that the encrypted image and the inverted share are to be printed symmetrically, control is passed to step 707 (704).

When the control is shifted to step 705, first, the shear stored in the storage device 640 is inverted upside down to generate a reverse shear, and the reverse shear is stored in the storage device 640 (705). A control signal and print data are sent to the printing device 640 so as to print the encrypted image and the inverted share stored in the storage device 640 vertically symmetrically (70).
6), end the process. On the other hand, when the control is shifted to the procedure 707, first, the share stored in the storage device 640 is
The printing apparatus prints the inverted image in the left-right direction by symmetrically printing the inverted image and the inverted image stored in the storage device 640 (707). A control signal and print data are sent to 650 (708), and the process ends. Step 706
In step 708, in addition to the encrypted image and the inverted share, if necessary, print data such as a dummy image, a folded curve, and an index are also sent to the printing device 650.

In the above description, the encrypted image and the shear are distinguished for convenience of explanation, but the same effect can be obtained even if the encrypted image and the shear are interchanged. In addition, since the present invention has a main feature in a portion relating to the alignment between an encrypted image and a shear, any image encryption other than those described above can be used. In the above description, “vertical symmetry” or “lateral symmetry” is based on the top and bottom of the original image, not on the basis of printed matter. Therefore, the position and orientation of the encrypted image and the inverted share can be arbitrarily selected. In the above description, the encrypted image, the shear image, and the dummy image have a rectangular shape, but may have another shape such as an ellipse. The printed image may be printed on the left or right, and the shape of the inverted image may not be the same as the shape of the inverted image as long as the position can be adjusted by another index. Also, if you print an illustration around the encrypted image and the inverted shire and mix the encrypted image and the inverted shire into the pattern of the illustration, the person who saw the printed matter thinks it is just an illustration and reverses the cipher image and the inverted This makes it harder to notice the presence of the screen, so that the effect of preventing eavesdropping can be further enhanced.

[0029]

The first effect is that it is possible to prevent a person from being stolen by a passing person or being stolen without being noticed by anyone while watching the public. This is because reading the content (original image) of the printed material involves an operation of folding the printed material and an operation of viewing the image over a ceiling light or a window.

The second effect is that it is possible to detect that the device has been stolen. This is because if someone steals the printed matter before the recipient, the printed matter will be creased. This can also be expected to have the effect of stopping anyone trying to see the privacy of the individual. Of course, if you copy the printed matter and fold the copied printed matter, you can see it without bending the original printed matter, but for that you have to take out the original printed matter, so it is difficult to see it in the eyes of the public. In addition, if a paint that is hard to copy (such as a light blue color) is used as a paint for printing, it is difficult to copy with a copy machine.

The third effect is that the cost can be reduced. This is because, in the present invention, prying eyes can be prevented only by printing an image to be printed, which has been subjected to image processing, without using a special device. Further, the printed contents can be read only by folding the printed material without using a special device.

The fourth effect is that the risk of leaking confidential information can be reduced. Because, in the present invention,
This is because printing can be performed by a conventional printing facility or printer, so that printing and shipping can be performed by oneself without outsourcing.

The fifth effect is that the present invention can be applied to any thin sheet or transparent sheet. This is because, in the present invention, prying eyes can be prevented only by changing the data of the image to be printed, and all that is required of the printed matter is that the folded printed matter can be seen through. Therefore, the present invention can be applied to not only facsimile recording paper but also, for example, a receipt of a register.

A sixth effect is that forgery of a printed matter by a copying machine can be prevented. This is because, when the printed matter of the present invention is copied by a copying machine, the encrypted image is deteriorated, but the degree of the deterioration can be visually recognized only by folding the printed matter and making it transparent. In addition, if a paint that is difficult to copy (such as a pale blue paint) is used as a paint for printing on a copying machine, the degree of deterioration can be increased.

A seventh effect is that it is difficult to eavesdrop on print contents from electromagnetic waves leaking from the printer. This is because if an encrypted image is obtained by eavesdropping on an electromagnetic wave leaked from a printer, only an encrypted image with noise is obtained, but when the encrypted images are superimposed, the amount of noise is approximately doubled.

The eighth effect is that it is intriguing. Conventionally, printed matter was taken out by a simple operation such as tearing an envelope or peeling a sheet, but in the present invention, a meaningful image emerges from a printed matter where only seemingly meaningless images are printed. It is. Therefore, if it is applied to a speed lottery or the like, an effect of attracting customers can be expected.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a printed matter of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the printed matter of the present invention.

FIG. 3 is a perspective view showing a third embodiment of the printed matter of the present invention.

FIG. 4 is a perspective view showing a fourth embodiment of the printed matter of the present invention.

FIG. 5 is a perspective view showing a fifth embodiment of the printed matter of the present invention.

FIG. 6 is a functional block diagram illustrating a configuration example of a printing method according to the present invention.

FIG. 7 is a flowchart illustrating the operation of the printing method according to the present invention.

FIG. 8 is a schematic diagram illustrating the principle of image encryption.

[Explanation of symbols]

10 sheet 11 encrypted image 12
Inverted shear 20 Dummy image 30 Fold curve 40
Index 50 Mount

Claims (6)

[Claims] At least one of an image encrypting means for generating two images of an encrypted image and a shear from an image and one of the two images of the encrypted image and the shear generated by the image encrypting means is vertically or horizontally shifted. Reversing means for reversing,
A printing system comprising: a non-inverted image and an inverted image of two images, an encrypted image and a shared image, which are printed vertically or symmetrically in accordance with the image inversion direction. 2. A printed matter in which two images, a cipher image and a shear image, are vertically and / or horizontally reversed on a light transmissive sheet, and one of the images is vertically or horizontally reversed. 3. On a light-transmitting sheet adhered on a backing paper with an adhesive which can be peeled off, two images of an encrypted image and a shared image are obtained after one image is inverted upside down or left and right inverted. Printed material printed symmetrically vertically or horizontally. 4. The printed matter according to claim 2, wherein an image formed by randomly selecting pixels is printed adjacent to the encrypted image or the seal. 5. The printed matter according to claim 2, wherein a bent curve is printed on an axis of symmetry between the encrypted image and the shear. 6. The printed matter according to claim 2, wherein a symbol for positioning is printed at a position symmetrical about an axis of symmetry between the encrypted image and the shear.