JPH03230975A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To prevent forgery and alteration wherein a main image is substituted because the regional separation from a medium becomes difficult by changing the density at the peripheral part of the main image in a variable density image obtained by an input means by an image processing means. CONSTITUTION:A coefficient group having coefficient distribution as the density distribution at an arbitrary lateral position is prepared. That is, the coefficient group is set so as to be equal to or larger than the number of the longitudinal and lateral pixels of an image 31 and constituted so that the central region is set to '1' the left and right outer peripheries are set to '0' and the intermediate thereof smoothly changes from '1' to '0' toward the outer peripheries. The density difference between the image 31 and the outside thereof is large and the separation and visual confirmation of the boundary thereof is easy. By multiplying the image corresponding to each pixel position and a coefficient, a processed image is obtained. In the processed image, the density difference between the periphery of the image 31 before processing and the left and right outsides thereof is eliminated, that is, the left and right outer peripheries 36 of the image 31 before processing are removed. When outer peripheral part of the image, that is, the boundary of the inside and outside of the image can not be visually confirmed, forgery and alteration become difficult.

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention is applicable to individuals, organizations, etc. that can be used as ID cards such as employee ID cards, credit cards, bank passbooks, various certificates, etc. The present invention relates to an image creation device for creating an image that identifies an image, and particularly relates to an image creation device for creating an image that is protected from forgery and falsification.

(Prior Art) For example, an ID card such as an employee ID card has a name, date of birth, expiration date, etc. attached thereto, as well as a face photo to identify the holder. Usually, with the main purpose of preventing tampering, a transparent sheet is glued or affixed to the surface of the photograph of the face, or the surface containing the photograph of the face is covered with a laminate using methods such as heat-sealing with a transparent film or high-frequency welding. ing.

In addition, credit cards and bank passbooks use authentication seals, PINs, signatures, etc. to identify the holder. In these cases as well, if a person's image can be displayed, it will be easier to identify the bearer, so it is desirable to be able to easily create a person's image and to display an image that is protected from forgery and tampering. Further, in credit cards and the like, a company name logo or the like is printed as a hologram image in order to identify the company to which the card belongs, but there is a need for a simple device for creating an image that identifies an organization or the like.

(Problem to be solved by the invention) In the above-mentioned ID card, the facial photograph used to identify and confirm an individual or group is covered with a transparent film to make it difficult to falsify or replace it with another facial photograph. It is not impossible to replace the photograph with the transparent film itself.

The present invention has been made in view of the above problems, and is based on the ID
The purpose of the present invention is to provide an image creation device that can be used for cards, bank passbooks, etc., and that can obtain images that are highly resistant to forgery and tampering.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an image input means for inputting a gray image including a main image such as a human figure that identifies an individual or a group, and a predetermined gray scale image for the gray image. The basic configuration includes an image processing means that performs the processing of Change the density of the area,
An object of the present invention is to provide an image creation device that prevents forgery and falsification by making it difficult to distinguish at least the boundary between the outermost periphery of an input grayscale image and the outside thereof.

(Function) In this way, since the density of the peripheral area of the main image such as a human figure is changed, it becomes difficult to separate the area between the main image and the medium on which this main image is recorded, so it is difficult to forge the main image by replacing it. - Can prevent tampering.

Furthermore, since no change in density is applied to the central region of the main image such as a human figure, there is no problem in specifying the recorded and displayed main image.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

In this embodiment, a human image will be described as an example of an image to be specified.

FIG. 1 is a block diagram showing the configuration of an image creation device according to the present invention. This device consists of an image input section 1 that inputs a person's image (usually a face photograph) that identifies an individual as a digital signal, an image processing section 2 that performs tampering prevention processing on the input image as described later, and a processed image that is transferred to a paper or plastic sheet. Alternatively, the main configuration is an image recording section 3 for recording on a plastic card or the like, and in some cases, a color conversion circuit 4, an enlargement/reduction circuit (not shown), etc. are added. The color conversion circuit 4 can also be placed after the image processing section 2.

FIG. 2 shows the configuration of the image processing unit 1.

The original image sheet 12 is a face photograph of a person who can be identified as a person identification image, or at least a face photograph of a person who can be identified as a person identification image is pasted thereon.

The image on the original image sheet 12 is illuminated by the light source 11,
A band-shaped area 13 of the image on the original image sheet 12 is imaged in a line shape at the same magnification by the distributed refraction skewer-shaped cylindrical lens array 14 on the light receiving surface of the CCD line sensor 15 . The images formed on the line sensor 15 are sequentially read out as electrical signals and become image signals 16. The element density of the line sensor 15 is 16 pixels/mm in this example. By moving the lens array 14 and the line sensor 15 by 1/16 mm perpendicular to the arrangement direction of the optical sensor array of the line sensor 15 while reading the image signal line by line, the entire image on the original image sheet 12 is read out one by one. /1
It can be read at a density of 6 mm.

Since the MTF characteristics of the lens array 14 are generally not ideal, the image signal 16 contains some blurring components, reducing resolution.

The image signal 16 is amplified by an amplifier 17 and then converted into a digital signal 19 by an A/D converter 18.

In such an image reading system, due to factors such as uneven illuminance of the light source and variations in dark current and sensitivity of each optical sensor composing the line sensor 15, even when reading an original image with a - density, the obtained image signal is It's not uniform. This phenomenon is usually called shading, and the shading correction unit 2
0 corrects these shadings and normalizes the image signal so that it becomes "1" if the original image is standard white, and "O" if it is black. Specifically, before reading the image of the original image 12, first, the black reference board 21 and the white reference board 22, which have a - density, are read at the end of the arrangement position of the original image 12, and the black and white reference signals are read. is stored in a line memory (not shown). When reading the original image 12, shading correction is performed by calculating the values stored in this line memory into the image signal. The aging correction section is described in detail in, for example, Japanese Patent Laid-Open No. 61-71764 by the present applicant.

In the above description, the information handled was described as a monochromatic signal, but the apparatus according to the present invention usually handles full-color signals. In other words, the image of the original image 12 is divided into the three primary colors of light, red, green, and
The colors are separated into blue and read out sequentially. Therefore, the image signals corrected and standardized by the aging correction section 20 are read out in the order of red, green, and blue based on a predetermined synchronization signal.

In addition, in the above explanation, the configuration of the image processing unit 1 has been described for the case where an original image sheet such as a facial photograph is read, or for example, a video camera equipped with a CCD sensor or an electronic still camera is used to take a photograph of the identified person. By doing so, a human image can also be obtained. In this case, there is no need to prepare a photograph in advance, and the created person identification image and the person can be confirmed on the spot, which further increases the effect of preventing forgery. Furthermore, it is also possible to use an image signal containing an image of a person transmitted from a computer or a transmission line, and in these cases, the input section of the present invention can be considered as a modified example in which the input section is used separately.

The color conversion circuit 4 in FIG.
The green and blue color signals are converted into signals corresponding to ink amounts suitable for the inks (cyan, magenta, yellow) used in the image recording section 3. There are many systems for this color conversion circuit, and for example, Japanese Patent Laid-Open No. 61-25372 can be referred to.

In some cases, the color conversion circuit 4 may be omitted by configuring the output of the image input section 1 to be the three primary colors of printing, cyan, magenta, and yellow.

The image processing unit 2 shown in FIG. 1 is the most important part of this device, and performs processing to prevent forgery or alteration of the created person identification image.

FIG. 3 is a diagram illustrating the processing operation in the image processing section 2. As shown in FIG.

A human image, such as the face photograph shown in FIG. 3(a), is usually manually generated as a rectangular image 31. A human face part 32 is placed approximately in the central area of this image 31. The facial region is the most effective for identifying a person because it is extremely characteristic of the person. In addition, the surroundings of the face part 32 include a background 33 and hair 34.
Alternatively, it may be clothing 35, that is, the surrounding area is insufficient as information for identifying the person. Therefore, in this device, this face part 32 is called a main image, and the density of the peripheral area of the face part 32 is changed to prevent forgery and tampering.

Figure 3(b) shows the concentration distribution at any horizontal position in Figure 3(a).
In this case, a coefficient group having a coefficient distribution as shown in FIG. 2(c) is prepared. In other words, this coefficient group is set to be equal to or larger than the number of pixels in the vertical and horizontal directions of the image 31, with the central area set as ``1'', the left and right outer peripheries as ``0'', and the middle area set as ``1''. It changes smoothly from "1" to "0" from the central region toward the outer periphery. In the same figure (b), the density difference between the image 31 and the outside is large,
It is easy to separate and visually recognize this boundary. In this process, the processed image shown in FIG. 10(d) is obtained by multiplying the image shown in FIG. 4(b) corresponding to each pixel position by the coefficients shown in FIG. In this processed image, there is no difference in density between the periphery of the image 31 before processing and its left and right outer peripheries, that is, the left and right outer peripheries 36 of the image 31 before processing are removed. In this way, the outer periphery of the image, that is, the inside of the image, and the outside of the image (the "base")
), it will be difficult to forge or alter the name.

FIG. 4 is a block diagram showing the actual circuit configuration of the image processing section 2, which includes a CPU 41, a clock control section 42, a counter 43, a coefficient ROM 44, and a multiplier 45.

The clock control unit 42 generates a clock that defines the pixel position to be processed among the vertical and horizontal pixel positions of the rectangular image 30 inputted by the image processing unit 1, and controls the address counter 43 configured as an up/down counter. Increment or decrement. The address counter 43 includes a row address counter and a column address counter for selecting the vertical and horizontal directions, that is, rows and columns, of an image expressed two-dimensionally, and has a coefficient RO.
Controls the address of M44. The coefficient ROM 44 supplies coefficient values corresponding to the above-mentioned coefficient group of the pixel specified by this row and column to one input of the multiplier 45.

The other input of the multiplier 45 is supplied with an image signal corresponding to the amount of yellow, magenta, and cyan ink output from the color conversion circuit 4.

Multiplier 45 multiplies this image signal expressed in 8 bits by the coefficient value and outputs the result. Since the output result may be expressed in 8 bits or more, if the output result is also 8 bits, an overflow processing section 46 is required to make the predetermined 8 bits valid.

In FIG. 3(c), the coefficient ROM 44 changes the amount of change in density in the range from coordinates x1 to x2 in the horizontal direction and from coordinates x3 to x4 in the horizontal direction, but does not change the amount of change in density by 1 in the vertical direction. In this case, in the processed image, the boundaries between the top and bottom of the image are visible. However, if even the boundaries of one side of the rectangular image cannot be visually recognized, it becomes difficult to replace the image containing the person image, and the effect of preventing forgery and falsification is exerted.

In order to increase the effectiveness of preventing forgery and tampering, all boundaries surrounding the image may be made invisible.

That is, FIG. 5 is an example of a group of coefficients of a coefficient ROM that changes the density around a human image in an elliptical manner.

For simplification, the number of pixels is 20 horizontally and 24 vertically, and the coefficient for 100% density is 10 and the coefficient for 0% density is 0. The density is set so that the density decreases radially from the center of the image toward the periphery in a monotonically decreasing curve, so that all border areas surrounding the image are not visible.

In the above explanation, the case where the surrounding density of the image is sufficiently low was described as an example, but the present invention can be applied regardless of the value of the surrounding density. In other words, if the surrounding density is sufficiently high, the density can be gradually increased from the center of the image toward the periphery, or as in the above example, the density can be gradually lowered until the density is sufficiently high. After the concentration becomes low, the concentration may be further increased to the ambient concentration with a -like concentration gradient toward the periphery.

Of course, these ambient densities may be instructed to the CPU 41 in advance, or the configuration may be such that the ambient densities of the recording medium are measured.

In addition, in device applications where it is known that the main image is located approximately at the center of the image, these density changes can be made using the coefficient ROM44 address counter 4
By devising the operation in step 3, the capacity of the coefficient ROM 44 can be reduced to about 1×4.

In other words, taking Figure 5 as an example, the coefficients corresponding to the upper left quarter area are stored in the coefficient ROM as shown in Figure 6, and the row address counter and column address counter are two-dimensionally set. It is only necessary to have a configuration in which the number of pixels is counted up to 2/31 of the maximum value of the number of pixels in the row and column of the image to be expressed, and then the number is counted down sequentially.

Further, FIG. 7 shows a modification of the configuration shown in FIG. 4 above. That is, the coefficient ROM 44, the multiplier 45, and the overflow processing section 46 are replaced with one ROM 70.

Further, FIG. 8 shows a modification in which a smoothing circuit 47 is added to the configuration of FIG. 4. The smoothing circuit 47 consists of a 3-line line memory, a register for several pixels, an adder, a divider, a selector, etc., and it can handle up to 4 neighboring areas including arbitrary pixels.
The average value of the pixel area defined by the x4 pixel matrix is 4X4, 3X3, 2X2, respectively. One value is selected from the average values of the IXI matrix and output.

Here, the smoothing circuit 47 is supplied with a row address and a column address, and changes the size of the area to be smoothed according to the pixel position specified by the row and column. In other words, if the main image itself is smoothed, the image will disappear and it will be inappropriate to identify the main image, so a 1×1 pixel matrix that is not smoothed is selected in the central area of the image including the main image. , the smoothing pixel matrix is enlarged toward the peripheral area of the image, and the image is blurred. By adding the smoothing circuit 47 in this manner, the boundary between the image and the outside of the image becomes less clear than when the density level of the image is changed, and the effect of preventing forgery and tampering is further enhanced. Further, when reading a photograph using an input means such as a scanner, the reading position may be slightly shifted due to the accuracy of the reading position. In such a case, smoothing has the additional effect of blurring the outline of the photograph where the reading position is very noticeable, thereby increasing the reading accuracy of a scanner.

The CPU 41 also determines the type of tamper-proof IF processing or the type of original image, and also determines whether the image signal to be processed is yellow or not.
The output of the coefficient ROM is controlled depending on whether the signal is magenta or cyan. Therefore, for example, it is possible to apply the above-described processing to only a specific color among yellow, magenta, and cyan, or to make the coefficient value 5 different for each color. In other words, in this case, it is possible to change the hue as well as the density. For example, if the surroundings of an image are chromatic, the density and hue of the border between the image and the surroundings of that image are made to match, and the border area is changed only by the density. It also has the effect of making the hue invisible.

FIG. 15 is an example in which the density and hue are changed by controlling the coefficient value, which is the output of the coefficient ROM, adaptively to the pixel value to be processed. In other words, 3 of yellow, magenta and cyan.
By supplying color image signals to the coefficient ROM 44 and determining the values of each of the three colors simultaneously, it is possible to change the hue while keeping the density constant, or to change the hue along with the density, thereby changing the image and its image. Processing is performed so that the density and hue match at the boundary with the surrounding area.

Further, a RAM may be used instead of the coefficient ROM used in this embodiment. In this case, it is preferable to provide a formula for creating a coefficient group to the CPU, and to calculate the coefficient value and write it to the RAM when the power of the apparatus is turned on.

Furthermore, although not shown, a plurality of coefficient ROMs may be prepared and switched depending on the situation. By configuring this configuration so that any coefficient group can be selected from among multiple coefficient groups, the type of tampering prevention processing can be changed based on personal data such as a specific person's date of birth or court affiliation. Also, the creation date of this image is 1-1
It is also possible to change the information based on the creation location, creation device number, etc. By allowing a single device to select a plurality of tampering prevention processes in this manner, it is possible to further prevent forgery and tampering.

Next, the image recording section will be explained.

FIG. 9 is a diagram showing the main part configuration of the image recording section 3 of FIG. 1.

In this embodiment, the recording methods are cyan 91 and magenta 92.
A thermal recording method using an ink ribbon 94 equipped with sublimation dye inks of three colors, , yellow 93, and yellow 93 is adopted.

This method records dye ink approximately in proportion to the amount of heat of the Thermal Gent 95, and is suitable for full-color recording. The image signal subjected to tampering prevention processing by the image processing unit 2 is supplied to a thermal head drive circuit 96 and converted into a pulse width for controlling the energization energy (recording energy) to each heating resistor of the thermal head 95. and supplied to the thermal head 95.

The thermal head 95 presses the recording paper 97 against the platen roller 98 side via the ink ribbon 94 and heats and sublimates the dye ink by selectively applying current to heating resistors arranged in a line, thereby printing the recording paper 97 on the recording paper 97. Transfer on top.

The transferred ink on the recording paper forms a recorded image.

FIG. 10 is a block diagram showing details of the main parts of the head drive circuit 96, and FIG. 11 is a timing chart thereof. Here, it is assumed that the thermal head is driven in two phases. Therefore, two systems of drive circuits are configured.

The image data of 8 bits per pixel is converted into data corresponding to the energization time of the thermal head, and is input to the shift register 100a. shift register 1
The output of 00a is transferred to shift register 100b.

The same clock signal is supplied to shift registers 100a and 100b. Shift registers 100a, 10
The output of 0b is connected to each latch circuit 101a in parallel.
, 101b. In addition, the latch circuit 101a,
101b has an enable signal E as shown in FIG.
N1 and EN2 are supplied alternately. Gate circuit 10
The outputs of 2a and 102b are sent to the driver 103a.

It is supplied to the heating resistors of each phase of the thermal head via 103b.

In this embodiment, temperature data of the thermal head 95 is fed back to the head drive circuit 96 (not shown). This is because the amount of ink transferred even with the same amount of energized energy varies depending on the heat accumulated in the thermal head itself and the environmental temperature, so the amount of energized energy is appropriately controlled based on the detected temperature of the thermal head itself. be.

By performing such control, the amount of energizing energy at normal temperature (Tn) can be reduced to 1, as shown in Figure 12.
When set to 00%, the amount of energized energy is decreased as the temperature increases, and the amount of energized energy is increased as the temperature decreases, regardless of the heat storage state of the thermal head.
A predetermined amount of ink is always transferred. thermal head 95
To detect the temperature, for example, as shown in FIG. 13, a thermistor 130 for temperature detection is connected to the thermal head 95.
The output of this thermistor 130 may be supplied to the head drive circuit 96 via the A/D converter 131.

Further, in order to reduce the energization energy of the thermal head, A2. Reduce the pulse width to the one shown in B2,
The amplitude values of the output voltages of the drivers 103a and 103b are calculated from the values shown in FIG. 14 AI and A2 to the values shown in FIG. 14 A3. It is sufficient to reduce it to the value shown in B3.

By using the sublimation dye thermal recording method as described above, a high-definition full-color image can be obtained relatively easily. Furthermore, if an image-receiving layer is formed on the recording surface in advance, recording can be performed on paper, plastic sheets, plastic cards, etc., and employee ID cards, ID cards, bank passbooks, various certificates, etc. can be easily created. Furthermore, since the present invention is not limited to the recording method used as the image recording means, for example, inkjet recording, electrophotography, heat-developable silver salt photography, etc. can be used.

Although the recorded image can be used as is, it is desirable to cover it with a transparent plastic film to further prevent forgery and tampering, protect the recorded image, and prevent the recording ink from fading.

In this case, normal lamination processing such as heat fusion or high frequency fusion is possible.

In the above explanation, we talked about creating a human image, but
The images targeted by the image creation device of the present invention are not limited to human images, but include, for example, handwritten signatures, signature fonts, impressions of seals, and other patterns that identify individuals, organizations, etc. as main images. cases are applicable. In other words, in the case of a signature or a seal imprint, the signature or stamp is placed on a prescribed mount, or within an area surrounded by a prescribed frame or colored in a prescribed color, or an item to which these are affixed. is used as the image sheet 12 in FIG. 2 above. Based on the correlation between the density and hue of the mount or color scheme area to be read and the density and hue of the recording medium to be recorded, the density and hue of the peripheral area of the mount or color scheme area is changed and the density and hue of the mount and color scheme area are changed to match the main body such as a signature or stamp. This makes it difficult to visually recognize the boundaries between images and prevents forgery and falsification. Furthermore, when reading these signatures and seal impressions, it is necessary to read the above-mentioned mount and predetermined frame as well in order to completely read the main image such as the signature or seal impression without missing anything. In such a case, according to the image creating apparatus of the present invention, the density around the image including the main image is changed, so that the edge of the mount, the predetermined frame line, etc. are made less noticeable.

In the above example, the image is subjected to forgery/tampering prevention processing and recorded as a processed image, but it is also possible to perform these two processes on the image in advance and record using this processed image.

Furthermore, it is preferable to use a pattern that does not include a pattern unique to optical meters as a pattern for the above-described density change processing.

[Effects of the Invention] As described above, if the image creation device of the present invention is used, the density of the peripheral area of the main image to be identified gradually changes toward the periphery, and the main image becomes indistinguishable from the surrounding area. It can prevent forgery and falsification, such as cutting out or replacing images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an overview of the apparatus for creating an image for person identification according to the present invention, FIG. 2 is a diagram showing the configuration of an image input section, FIG. 3 is a diagram explaining the present invention in detail, and FIG. 4 is a block diagram showing the main part configuration of the processing circuit, FIG. 5 is a diagram showing an example of a coefficient ROM, FIG. 6 is a diagram showing coefficients corresponding to a predetermined area, and FIGS. 7 and 8 are modifications of the processing circuit. 3. A block diagram showing an example; FIG. 9 is a diagram showing the main part configuration of the image recording section in FIG. 1; 3 FIG. 10 is a block diagram showing details of the main part of the head drive circuit; FIG. 11 is a timing chart; Figure 12 shows room temperature (T
Figure 13 is a diagram showing the amount of energized energy in case n), and Figure 13 is a configuration diagram in which a thermistor for temperature detection is connected to the thermal head.
FIG. 14 is a diagram showing various pulse widths, and FIG. 15 is a diagram showing coefficient values that are output from the coefficient ROM adaptively to the pixel values to be processed.

Claims (1)

[Claims] (1) At least an image input means for inputting a grayscale image including a main image that identifies an individual or a group, an image processing means for performing predetermined processing on the grayscale image obtained by the input means, and the image processing In an image creation device, the image processing means records a processed image obtained by the input means on a recording medium, and the image processing means records the processed image obtained by the input means around the main image among the grayscale images obtained by the input means. An image creation device that is characterized by changing the density of the area.