JPH06217122A - Image reader and pattern forming method - Google Patents

Abstract

PURPOSE:To recognize a specified original by detecting a mark printed in infra red absorption ink, for example, other than visible ink arranged with prescribed density. CONSTITUTION:Adders 121-1-121-1 respectively simply acid color components for four picture elements, provide YR, YG, YB and YIR by outputting high-order 8 bits and input them to subtracters 122-1-122-3. Then, difference from the respective components of attention picture element signals is calculated, respective high-order 5 bits are inputted to a decision LUT 128 composed of a ROM and when the respective bits are smaller than a constant K, '1' is outputted. Similarly, in the case of an infrared read signal, YIR and XIR of respective 8 bits are inputted to a decision LUT 129 composed of a ROM and when the difference of YIR and XIR is larger than a constant L1 or when YIR/XIR is larger than a constant L2, '1' is outputted from the LUT 129. The respective LUT outputs are ANDed by an AND gate 130 and when the output is '1', the pattern is detected. Thus, the copy operation of the specified original is blocked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device for reading visible and non-visible optical information and a pattern forming method for recognizing a specific original.

[0002]

2. Description of the Related Art Conventionally, as image quality and color of copying machines have increased, there has been a fear of forgery of banknotes, stamps and securities. On the other hand, with respect to the recognition of banknotes, various methods have been devised, such as detecting the pattern of a stamp of a banknote.

Further, the present applicant has proposed a method of recognizing a banknote or the like from the color tone of the original document by utilizing the fact that the pattern of the original document is formed in a specific color tone.

[0004]

However, there are an enormous variety of printed materials, including those that are already in circulation and those that are newly distributed in the future, for which the counterfeiting action should be prevented, and the characteristics of the pattern are used. There is a problem that the method cannot handle it. Further, if a visible pattern is used as a recognition mark, it becomes visually conspicuous, which is not preferable in terms of design. Therefore, an object of the present invention is to provide an image reading apparatus capable of accurately discriminating a specific document.

Another object of the present invention is to provide a method of forming a pattern for recognizing a specific document which is highly versatile and inconspicuous to human eyes.

[0006]

In order to solve the above problems, the image reading apparatus of the present invention has an input means for inputting image information other than visible and a density of the image information other than visible per unit area. And a determination means for determining the specific document based on the above.

Further, the pattern forming method of the present invention makes it possible to determine a specific original by forming a pattern on a recording medium at a predetermined density per unit area using a recording agent that generates image information other than visible. It is characterized by having done.

[0008]

[First Embodiment] The present invention will be described below based on a preferred embodiment.

In the following embodiments, a copying apparatus is shown as an application example of the present invention, but the present invention is not limited to this and can be applied to various other apparatuses such as a facsimile image scanner.

FIG. 2 shows an external view of the apparatus according to the first embodiment of the present invention.

In FIG. 2, reference numeral 201 denotes an image scanner section, which is a section for reading a document and performing digital signal processing. A printer unit 200 is a unit that prints out an image corresponding to the original image read by the image scanner 201 on paper in full color.

In the image scanner unit 201, 20
Reference numeral 2 denotes a document plate, which is a platen glass (hereinafter, platen) 2
It is used to fix the original document 204 on 03. The original 204 is illuminated with the light of the halogen lamp 205. Reflected light from the original 204 is guided to mirrors 206 and 207, and an image is formed by a lens 208 on a four-line sensor (hereinafter referred to as CCD) 210 including four CCD line sensors. The CCD 210 color-separates the light information from the original and sends it to the signal processing unit 209 as the red (R), green (G), and blue (B) components of the full-color information and the infrared information (IR) components. . Note that 205 and 20
6 is a speed v, and 207 is a 1/2 v, which mechanically moves in a direction (hereinafter, sub-scanning direction) perpendicular to the electrical scanning direction (hereinafter, main scanning direction) of the line sensor to scan the entire surface of the document. To do.

Reference numeral 211 is a standard white plate, which is used for the sensors 210-1 to 210-4 at the time of shading correction.
It is used to generate data for correction of read data corresponding to the line sensors of R, G, B components.

As shown in FIG. 19, this standard white plate exhibits a substantially uniform reflection characteristic from visible light to infrared light, and has a white color in the visible.

Using this standard white plate, the IR sensor 210
It is used for correction of output data for infrared light of -1 and correction of output data of R, G, B visible sensors 210-2 to 210-4.

The signal processing unit 209 electrically processes the read signal, decomposes it into magenta (M), cyan (C), yellow (Y), and black (BK) components, and sends them to the printer unit 200. . In addition, the image scanner unit 201
M, C,
One component of Y and BK is sent to the printer 200 in a frame-sequential manner, and a total of four document scans completes one color image formation.

The image signals of M, C, Y and BK sent from the image scanner unit 201 are laser driver 21.
Sent to 2. The laser driver 212 modulates and drives the semiconductor laser 213 according to the image signal. The laser light is a polygon mirror 214, an f-θ lens 215, and a mirror 21.
The photosensitive drum 217 is scanned by way of the scanning line 6.

Numerals 219 to 222 are developing units, which are a magenta developing unit 219, a cyan developing unit 220, and a yellow developing unit 2.
21 and a black developing device 222, four developing devices alternately contact the photosensitive drum, and develop the electrostatic latent images of M, C, Y, and BK formed on the photosensitive drum 217 with the corresponding toners.

Reference numeral 223 denotes a transfer drum, which is a paper cassette 22.
4 or 225, the paper fed from this transfer drum 2
The toner image developed on the photosensitive drum 217 is transferred to a sheet by winding the sheet around the sheet 23.

After the four colors M, C, Y, and BK have been sequentially transferred in this manner, the sheet passes through the fixing unit 226 and is discharged.

The halogen lamp 205 is commonly used for reading visible information and infrared light information, and has both the illumination wavelength components necessary for reading the above two types of information. By making the illumination system common in this way, the illumination light beams of different wavelength components for reading visible and infrared information are both effectively applied to the document.

FIG. 18A shows the CCD 2 used in this embodiment.
The structure of 10 is shown.

Here, 210-1 is a light receiving element array for reading infrared light (IR), and 210-2, 210-
3, 210-4 are light receiving element arrays for reading R, G, B wavelength components in order.

IR, R, 210-1 to 210-4
G and B sensors are 10 μm in the main and sub scanning directions
With an opening of.

The four light-receiving element arrays having different optical characteristics are arranged on the same silicon chip so that the IR, R, G and B sensors are arranged in parallel with each other to read the same line of the original. It is configured monolithically.

By using the CCD having such a structure, an optical system such as a lens is commonly used for reading visible light and reading infrared light.

This makes it possible to improve the accuracy of optical adjustment and the like, and also facilitate the adjustment.

Reference numeral 210-5 is a glass plate having a characteristic of cutting infrared light in the shaded area and has a thickness of about 300 μm.

The infrared cut characteristics of the shaded area can be obtained by the dichroic mirror 210-11 formed of a vapor deposition film. The characteristics of this infrared cut are shown in FIG.

Here, the glass plate is adhered to the chip surface so that the vapor deposition surface is on the sensor side.

FIG. 18B shows an enlarged view of the light receiving element.
Each sensor has a length of 10 μm per pixel in the main scanning direction. Each sensor has 5000 pixels in the main scanning direction so that the A3 original can be read in the lateral direction (297 mm) at a resolution of 40 dpi. The distance between the lines of the R, G, and B sensors is 80 μm, and 400 lpi
Each line is separated by 8 lines with respect to the (line per inch) sub-scanning resolution.

IR sensor 210-1 and R sensor 210-
The line spacing of 2 is 160 μm (16
Line). In this way, the IR sensor 210-
1 and the R sensor 210-2 by making the distance between them wider than the other sensors, the vapor deposition surface 210-1 of the glass plate 210-5.
1 corresponds to the sensors 210-2 to 210-4, and the non-evaporated portion corresponds to the sensor 210-1.
It is possible to make the mounting position accuracy low when -5 is bonded to the sensor chip surface.

FIG. 8 shows a cross-sectional view of the sensor used in this embodiment.

The line sensors 210-1 to 210-4 are monolithically formed on a common silicon chip 210-14, and the surface of each line sensor is IR, R, G, B.
Optical filter 210 for obtaining a predetermined spectral characteristic of
-6 to 210-10 are attached. 210-8, 2
Reference numerals 10-9 and 210-10 denote pigment filters that transmit the R, G, and B wavelength components, respectively, and thus the sensor 21
From 0-2, 210-3, 210-4, R, G, B respectively
Is obtained. The IR sensor 210-1 includes R filters 210-6 and 2 having the same optical characteristics as 210-8.
A B filter 210-7 having the same optical characteristic as that of 10-10 is attached in an overlapping manner, and only IR light having a wavelength of 750 nm or more is read by a combination of R and B filter characteristics described later.

The glass plate 210-5 is attached in the vicinity of the sensor surface, and the vapor deposition film 21 for blocking infrared light is further provided.
0-11 are directed to the sensor side. This is because the light to the sensor is condensed by the lens 209 as shown in FIG. 24, and the light fluxes to the sensors are overlapped at the positions apart from the sensor surface. That is, the sensor 2
If the infrared cut filter 210-11 is made to act only on the light to 10-2 to 210-4, the infrared cut filter 210-1 is provided in the vicinity of the sensor where IR light and R light do not overlap.
This is because it is necessary to attach 1.

Therefore, the infrared cut filter 210-1
By placing 1 near the sensor surface, the IR filter
It is possible to widen the mounting allowable width a for setting between the luminous flux of R and the luminous flux of R, and it is possible to reduce the mounting accuracy of the glass plate 210-13 to the sensor chip.

When an infrared cut filter is attached to the surface of the glass 210-5 on the side opposite to the sensor, the IR light flux and the R light flux overlap, so that a sufficient margin is provided for the R light flux and the red light flux is red. If you try to place an outer cut filter I
This is because most of the IR luminous flux imaged on the R sensor 210-1 is blocked and the IR signal level is lowered.

Referring to FIG. 21, the IR of CCD 210,
The spectral characteristics of the filters of the R, G, and B line sensors will be described.

The characteristic indicated by R is the output characteristic of the sensor by the filter 210-8 and the filter 210-6, and is sensitive to light in the red wavelength range and the infrared wavelength range. The characteristic indicated by G is the output characteristic of the sensor by the filter 210-9, and is sensitive to light in the green wavelength band and the infrared wavelength band. Characteristic filter 210-10 and filter 2 indicated by B
The output characteristics of the sensor according to 10-7 are sensitive to light in the blue wavelength range and the infrared wavelength range.

The IR sensor 210-1 has a filter 210.
Since -6 and 210-7 are mounted in an overlapping manner, FIG.
It has sensitivity only to light in the infrared region shown by the shaded area.

As can be seen from this figure, the R, G and B filters 210-8 to 210-10 are sensitive to infrared light of 700 nm or more. Therefore, the infrared cut filter 210-11 has the characteristics shown in FIG.

FIG. 20 shows an infrared absorbing material SIR-159 manufactured by Mitsui Toatsu Chemicals used as a detection mark for a specific original in this embodiment.
The spectral absorptance of is shown. In this embodiment, in order to read the presence or absence of this infrared absorbing material with the IR sensor,
Only infrared light from nm to 850 nm is detected.

Therefore, the lens 209 is provided with a far infrared cut filter using a dichroic mirror shown in FIG. This filter is provided not only for the IR sensor 210-1 but also for the R, G, B sensors 210-2 to 210-4 without causing any actual damage. As a result, the filter attached to the lens 209 can be designed in consideration of only the far-infrared cut characteristic, and good far-infrared cut characteristic can be realized with a simple interference film structure.

FIG. 1 is a block diagram showing the flow of image signals in the image scanner unit 201. The image signal output from the CCD 210 is an analog signal processing unit 3001.
After inputting to, gain adjustment and offset adjustment,
8b for each color signal by the / D converter 3002 to 3005
It is converted to a digital image signal of it. After that, it is input to the shading correction units 3006 to 3009, and known shading correction using the read signal of the standard white plate 211 is performed for each color.

Reference numeral 3019 denotes a clock generator which generates a clock for each pixel. A line counter 3020 counts clocks and generates a pixel address output of one line. Reference numeral 3021 denotes a decoder, which decodes the main scanning address from the main scanning address counter 3020 to generate a C for each line such as a shift pulse or a reset pulse.
CD drive signal, VE signal that represents the effective area in the one-line read signal from CCD, and line synchronization signal HSYN
Generate C. The counter 3020 is cleared by the HSYNC signal and starts counting the main scanning address of the next line.

As shown in FIG. 8, since the light receiving portions 210-1, 210-2, 210-3, 210-4 of the CCD 210 are arranged with a predetermined distance, the line delay elements 3010, 3011, 3012. At, the spatial deviation in the sub-scanning direction is corrected. Specifically, the IR, R, and G signals for reading the original document information in the sub-scanning direction with respect to the B signal are line-delayed in the sub-scanning direction to match the B signal.

Reference numerals 3013, 3014, and 3015 denote light amount / density converters which are constituted by a look-up table ROM and convert the R, G, B luminance signals into C, M, Y density signals. Reference numeral 3016 is a known masking and UCR circuit, and detailed description thereof will be omitted, but the input Y, M,
With the C3 primary color signal, Y, M, C, and Bk signals for output are sequentially output with a predetermined bit length, for example, 8 bits, for each reading operation.

An identification unit 3 detects a specific pattern in the original document, which is a feature of the present invention.

Reference numeral 3018 denotes a CPU section, which controls the original reading optical system, sequence control such as ON-OFF control of the original illumination lamp 205, and the pixel section signal V in the sub-scanning direction.
Generate SYNC. In addition, the selector 3017 is controlled according to the determination result from the recognition unit 3 to output the port output to the printer instead of the read signal to prevent the copy operation of the specific document.

FIG. 25 shows the timing of each control signal.

The VSYNC signal is an image effective section signal in the sub-scanning direction, and in the section of "1", image reading (scanning) is sequentially performed (C), (M), (Y), (B).
k) form the output signal. VE is an image effective section signal in the main scanning direction, which takes the timing of the main scanning start position in the section of "1". The CLOCK signal is a pixel synchronization signal and transfers image data at the rising timing of 0 → 1.

The image pattern to be detected by the present invention is outlined in FIG. FIG. 3A is an example of a pattern made using transparent ink composed of the transparent infrared absorbing dye having the characteristics shown in FIG. That is, a plurality of minute patterns b are printed using the above transparent ink on the pattern of the area a recorded with ink that does not absorb a specific infrared light. FIG. 3B is a diagram showing the pattern b in detail, and each pattern is substantially circular with a radius of 127 μm.
They are printed horizontally and vertically at 254 μm intervals. The shape, size, and arrangement of this pattern are not limited to this example.

Since the pattern has almost the same color in the visible range as shown in FIG. 20, the pattern b is indistinguishable by human eyes, but can be detected in the infrared range.
Although a pattern of about 127 μm square is shown as an example for the following description, it is 400 dpi (dot per).
Inch), if the area of b is read, the size becomes about 4 pixels as shown in the figure.

The details of the identification unit shown in FIG. 1 will be described with reference to FIG. Reference numerals 10-1 to 10-4 in FIG. 4 denote image data line delay units configured by FIFOs, in which the address pointer is initialized by a line synchronization signal HSYNC (not shown), and data is written in pixel units by the CLOCK signal. Read out. Each is 32bit R, G,
Delay the B and IR data by one line at a time.

First, the input signal is input to the flip-flop 11-
A pixel data of A is generated by delaying and holding two pixels at 1 and 11-2.

Furthermore, the line memories 10-1 and 10-2
Then, the pixel data of C is generated with a delay of 2 lines. The C pixel data is delayed by 2 pixels and 4 pixels, respectively, and pixel data of the target pixel data X and B is generated. Similarly,
The pixel data of D are input to the determination unit 12, respectively.

Here, the positional relationship of the four pixels A, B, C and D in the vicinity of the target pixel position X is as shown in FIG. That is, if the pixel X of interest is reading the ink b in FIG. 3, all of the above A, B, C, and D are reading the image of the pattern located around it.

The determination algorithm of the determination unit 12 used in this embodiment is shown below.

Now, the R component, G component, B component, and IR component of the read signal forming the A pixel signal are respectively AR, A
If G, AB, and AIR are used, the average values YR, YG, YB, and YIR of the read signals of the respective color components of R, G, B, and IR in the same pixel signals of B, C, and D are expressed by the following equation. Ask.

YR = 1/4 (AR + BR + CR + DR) YG = 1/4 (AG + BG + CG + DG) YB = 1/4 (AB + BB + CB + DB) YIR = 1/4 (AIR + BIR + CIR + DIR) The average value Y determined by the above equations, respectively.
And the pixel X of interest.

That is, R component of X, G component, B component,
If the IR components are XR, XG, XB, and XIR, It is determined that there is a pattern when the following equation is satisfied.

ΔR <K and ΔG <K and ΔB <K and (ΔIR <L1 or YIR / XIR <L2 (K, L1 and L2 are constants), that is, the target pixel X and its surroundings A, B, C and D In comparison, when the difference in tint is small (smaller than K) in the visible region and there is a difference of a constant L1 or more in the infrared region, or the pixel of interest X in the infrared region.
When the ratio of the level of 1 to the peripheral level is equal to or greater than the constant L2, it is determined that there is a specific pattern.

In the determination of the infrared region, not only the difference but also the ratio is considered in consideration of the decrease in the level of the infrared signal due to the stain on the document. In this embodiment, it is assumed that the infrared reading signal is attenuated as a whole due to the influence of dirt, and the influence of dirt is eliminated by detecting the ratio.

Further, as described above, the density of the detected specific pattern is counted. The concept of the pattern arrangement example and the density will be described with reference to FIGS. 9 and 10. When a 3 × 3 array as shown by ● in FIG. 9 is read in an 8 × 8 window W1, counting the number of patterns that occupy more than half of the pixels, 16 out of 64 pixels form a pattern. When detected and read in window W2, nine pixels detect the pattern. This is the case where W1 has the highest density. W2
Indicates a case where a quarter of the pattern arrangement is covered, and the case where the phase of the document and the window is most shifted is called the case where the density is the lowest. Figure 10 shows 4 windows and arrays
The case where it is tilted by 5 ° is shown. Densest window W1
Detects 16 patterns, and W2, which has the lowest density, detects 6 patterns. The inclination between the original and the window can be any arbitrary angle, but at least 2.25 patterns are included in the window. Therefore 6
When at least 6 patterns out of 4 pixels are detected, it can be determined that the document is a document whose forgery should be prevented.

Further, as shown in FIGS. 9 and 10, in the case of 13 pattern arrangements in which 4 ◯ are added to 9 ,
In W2 of FIG. 9, 11 patterns are detected, and W of FIG.
In 2, 7 patterns are detected. This can improve the certainty of the determination.

The determination unit 12 which has implemented the above algorithm comprises a pattern detection unit (FIG. 7) and a density detection unit (FIG. 6).

FIG. 7 shows the pattern detection section. Adder 12
1 simply adds the respective color components of 4 pixels and outputs the upper 8 bits, and outputs YR, YG, YB, and YI, respectively.
Get R. The subtractor 122 obtains the difference from each component of the pixel signal of interest, inputs the upper 5 bits of each of the ΔR, ΔG, and ΔB components to a determination LUT 128 formed of a ROM, and when each of them is smaller than a constant K. , 1 is output from the LUT 128. Similarly, in the case of an infrared read signal, 8 bits of YIR and XIR are input to the address terminal of the determination LUT 129 composed of ROM, and the above-mentioned ΔIR is input.
= ΔIR> L1 or Y calculated by YIR-XIR
When the determination result of IR / XIR> L2 is satisfied, LU
1 is output from T129.

The output of each LUT is ANDed by the AND gate 130, and when it is 1 at the output terminal, the pattern is detected.

The result of the determination is sent to the density detector of FIG. Reference numerals 701, 702, ..., 707 denote seven D flip-flops (hereinafter referred to as DFFs) arranged in series, which sequentially delay the input signal by the pixel clock CLOCK signal, and VE = “0”, that is, non-image. It is cleared to "0" in the section.

Reference numeral 738 is a 4-bit up / down counter, 737 is an EX-OR gate, and 740 is an AND gate.

The output of the counter 738 is cleared to "0" in the section where VSYNV or VE is "0", and X _t =
When the X _t-7 is held, at the time of X _t = 1 and X _t-7 = 0 is counted up, and is counted down when the X _t = 0 and X _{t -7} = 1. By latching this counter output with CLK8 of 8 clock cycles by the latch 739, 8 pieces of input data X _t input in one cycle of CLK8
Is output (the number of 1). Furthermore, the output is 1
Line-by-line FIFO memories 721, 722, ..., 72
The data of 8 lines is simultaneously input to the adder 741 by 7 and the sum thereof is output. As a result, the sum SUM of the number of 1's in the 8 × 8 window is output at 0-64.

Reference numeral 742 is a comparator, which is an adder 74.
The output SUM of 1 is compared with the comparison value TW preliminarily determined by the CPU 3018, and the result is output as "0" or "1". From the above description, for example, TW = 5 can be set.

The comparison result is input to the latch 3022 of FIG. Latch output is input port P of CPU 3018
10 is input, the CPU recognizes that an infrared absorption mark having a predetermined density is detected. Prior to the start of the copy sequence, the CPU clears the latch 3022 by the output port P9 signal and prepares for the next pattern detection.

The control operation of the CPU for the normal copy operation and the accompanying recognition mark determination operation will be described below with reference to FIG.

The operator sets the original 204 on the platen 203.
When a copy operation is started by an operating unit (not shown), the CPU 3018 controls a motor (not shown) to move the reflection mirror 206 to below the standard white plate 211.

Next, the halogen lamp 205 is turned on, the standard white plate 211 is irradiated, and the shading correction unit 300 is illuminated.
6 to 3009, shading data for IR, R, G, and B signals are sampled (step 1).

Next, the port output P9 is set to 0 and the latch 30
The output of 22 is cleared to 0, the output of P8 is cleared to 0, the A input force of the selector 3017 is selected and masked, and the UCR image signal is supplied to the printer. After that, the P9 output is set to 1 and the clear operation of the latch 3022 is completed (step 2).

Next, the document reading operation is performed four times in accordance with the four-color image recording operation of M, C, Y, and BK in the printer unit to perform image recording, the recognition mark is detected, and the detection result is obtained. The recording operation is controlled accordingly.

First, for magenta recording, the CPU masks, sets processing conditions for magenta in the UCR processing section, scans the optical system, gives a magenta signal to the printer, and returns the optical system to the scanning start position after scanning ( Step 3).

During the reading of the original, the CPU periodically reads the port 10 and determines whether the input is 1. If P10 is 1, it is determined that the specific document is being copied, and in step 7, the outputs of P0 to P7 are set to FFH, the output of P8 is set to 1, and the solid signal of FFH is output to the printer. However, the normal copy operation thereafter is blocked.

Similarly, in steps 4 to 6, cyan,
Recording control is performed for yellow and black, and the CPU is in the meantime.
Periodically checks the state of P10, and if it is 1, outputs solid FFH data to the printer in step 7.

If P10 = 1 is detected during cyan recording, magenta will perform the normal copying operation.
The cyan, yellow, and black recordings are all recorded in solid FFH.

<Second Embodiment> In the second embodiment, as shown in FIG.
As shown in FIG. 1 (A), the pattern diameter is about 180 μm, that is, a diameter circumscribing 2 × 2 pixels, and a maximum of 4 pixels is included regardless of the angle between the original and the window. Further, as can be seen from FIG. 11B, no matter what the phase relationship between the window and the document is,
Pixels are included. Also, as can be seen from FIG. 11 (A),
Since the pattern covers a maximum of 4 pixels, a minimum pattern spacing of 508 μm is ensured to reliably detect the infrared absorption pattern. Further, in this case, if a size of 16 × 16 is prepared as the density detection window, the same density standard as in the first embodiment can be applied. In the density detector of FIG. 6, the DFFs 701, ..., 707 are set to 1
, 727, ..., 727 for 16 lines, and instead of CLK8, a clock for 16 pixel clock cycles may be adopted.

12 and 13 are schematic diagrams of density detection corresponding to FIGS. 9 and 10. Since W2 having the lowest density includes 9/4 patterns (or 13/4 patterns) as described above, at least 9 (or 11) patterns are detected in FIG. 12, and at least 4 patterns are detected in FIG. The number (or 5) is detected.

<Third Embodiment> In the first and second embodiments, the comparator 742 of the density detecting section of FIG.
Although the minimum value was checked, as is clear from the above explanation, if the pattern is arranged according to a predetermined rule, it is more sure that the pattern is a regular pattern array by limiting the maximum number of detections. it can.

FIG. 14 shows a density detecting section with the maximum density limited. A comparator 743 and an AND gate 744 are added to FIG. 6 to output the output SU of the adder 741.
The comparison values TV and TW preset by M and the CPU are compared, and when SUM is larger than the value TW and smaller than TV, it is detected that the pattern arrangement is a predetermined pattern arrangement. In the case of FIG. 12 and FIG. 13, TV = 17, TW = 4
Becomes

<Fourth Embodiment> By further arranging a pattern array having a predetermined density (for example, a 3 × 3 array) in a coarse and dense manner as shown in FIG. Can be detected. In the example of FIG. 15, 3 × 3
Is further arranged at a cycle of 24 pixels. For example, if a region of about 4 mm × 4 mm is secured in the document, a 3 × 3 pattern can be printed 3 × 3. The determination result of the specific pattern by the density detection in the 8 × 8 window for such an array pattern has regularity as shown in the figure.
The difference between "1001001" and "1101101" is due to the phase of the document and the window. However, by determining the pattern arrangement in advance, it is possible to prepare a plurality of types of rules in consideration of these phases. As a result, the original can be specified by pattern matching the determination result of the 8 × 8 density detection window again with the 8 × 8 window. Similarly, it is possible to perform matching by preparing a rule in consideration of an arbitrary inclination between the original and the window.

FIG. 16 shows the pattern matching section. The final output of FIG. 6 or FIG. 14 is used as the input. FIG.
Is a video data line delay unit, and a sync signal HSYNC having a cycle of eight lines of the line sync signal HSYNC.
At 8, the address pointer is initialized, and data writing and data reading are performed by the synchronizing signal CLK8 having an 8 clock cycle of the pixel clock CLOCK. FF is a flip-flop, which operates in synchronization with CLK8. The eight determination signals in the main scanning direction are input to each matching unit, and after serial-parallel conversion, they are compared with the data set in the preset value register by the CPU, and if they are equal, "1" is output. The AND gate outputs "1" when all these eight matching results are "1". This output is the final determination result in FIG. When matching with a plurality of types of patterns, one set of eight matching units may be provided. The pattern matching means is not limited to this example. Figure 15
In the case of, the preset register contains [92HEX, 00
HEX, 0HEX, 92HEX, 00HEX, 00HE
X, 92HEX, 00HEX] is set in the first matching section, and [DBHEX, DBHEX, 00HE
X, DBHEX, DBHEX, 00HEX, DBHE
X, DBHEX] is set to a second matching unit.

<Fifth Embodiment> In the fifth embodiment, as the judgment unit 12 of FIG. 4, a pattern detection unit (FIG. 7) and an 8 × 8 density detection unit (FIG. 6 or FIG. 14) are used as shown in FIG. The 64 × 64 density detector is again provided in the subsequent stage of (). 64 x 6
4 The density detector outputs the output of the density detector for every 8 × 8 pixels to 8
× 8 times addition, that is, 64 × 64 shown in FIG.
8 × 8 “0” s or “1” s obtained from pixels are added. The configuration of the 64 × 64 density detection unit is the same as that of FIG. 6 except for the cycle of the synchronization signal, and detailed description will be omitted. 8-line cycle sync signal HSYNC8 and 8-pixel cycle sync signal CL
It operates by K8 and the synchronization signal CLK64 having a cycle of 64 pixels.

In the example of FIG. 15, if the value to be compared with the added value is set to "8", the specific original can be recognized regardless of the phase between the original and the window. Further, it is easy to predetermine a comparison value in consideration of the inclination between the original and the window.

<Other Embodiments> The present invention is not limited to the copying apparatus, but can be applied to other apparatuses having an image reading means such as a facsimile and an image scanner.

The present invention is characterized by detecting the density, and the shape of the infrared absorption mark is not limited to the circular shape. Furthermore, the arrangement of the plurality of marks is not limited to the matrix.

[0093]

As described above, according to the present invention,
A specific document can be recognized by having a unit for detecting marks printed with infrared absorbing ink other than visible ones arranged at a predetermined density.

[Brief description of drawings]

FIG. 1 is an image signal control unit.

FIG. 2 is a configuration diagram of a color copying apparatus using the present invention.

FIG. 3 is a configuration diagram of a specific document identification pattern in the first embodiment.

FIG. 4 is a diagram for detecting a specific pattern in the first embodiment.
Dimensional area signal generator.

FIG. 5 is a specific pattern detection reference pixel in the first embodiment.

FIG. 6 is a density detection unit according to the first embodiment.

FIG. 7 is a specific pattern detection unit according to the first embodiment.

FIG. 8 is a block diagram of a CCD.

FIG. 9 is a pattern array diagram in the first embodiment.

FIG. 10 is a pattern array diagram in the first embodiment.

FIG. 11 is a pattern configuration diagram in the second embodiment.

FIG. 12 is a pattern array diagram in the second embodiment.

FIG. 13 is a pattern array diagram in the second embodiment.

FIG. 14 is a density detector in the third embodiment.

FIG. 15 is a pattern array diagram in the fourth embodiment.

FIG. 16 is a pattern matching unit in the fourth embodiment.

FIG. 17 is a configuration of a determination unit according to the fifth embodiment.

FIG. 18 is a block diagram of a CCD.

FIG. 19: Spectral reflectance of standard white plate.

FIG. 20 is a spectral transmittance of a specific pattern.

FIG. 21 is a spectral characteristic diagram of a visible line sensor and a filter characteristic diagram for an infrared reading sensor.

FIG. 22 is a characteristic diagram of an infrared cut dichroic filter.

FIG. 23 is a characteristic diagram of a far infrared cut filter.

FIG. 24 is an attachment diagram of an infrared cut glass to a CCD sensor.

FIG. 25 is a timing chart of an image control signal.

FIG. 26 is a control flow chart of the CPU.

[Explanation of symbols]

 210-5 glass plate 210-1 line sensor for IR 210-2 line sensor for R 210-3 line sensor for G 210-4 line sensor for B

Claims (7)

[Claims] 1. An image reading apparatus comprising: an input unit for inputting image information other than visible image; and a determination unit for determining a specific document based on a density per unit area of the image information other than visible image. . 2. A pattern, wherein a specific original can be determined by forming a pattern on a recording medium at a predetermined density per unit area using a recording agent that generates image information other than visible light. Forming method. 3. A first reading unit for reading visible information from a document, a second reading unit for reading information other than visible information from a document, and based on the information read by the first and second reading units. Detecting means for detecting the specific pattern, counting means for counting the detection result of the detecting means within a predetermined area, and determining means for determining the original as a specific original based on the counting result of the counting means. Image reading apparatus having a. 4. A first reading unit for reading visible information from a document, a second reading unit for reading information other than visible information from a document, and based on the information read by the first and second reading units. Detecting means for detecting the specific mark, first counting means for counting the detection result of the detecting means within a predetermined area, processing means for processing the counting result of the first counting means, and the processing means. An image reading apparatus having a second counting unit that counts the processing result and a determination unit that determines whether the document is a specific document based on the counting result of the second counting unit. 5. A first reading unit for reading visible information from a document, a second reading unit for reading information other than visible information from a document, and based on the information read by the first and second reading units. A detecting means for detecting the specific mark, a counting means for counting the detection result of the detecting means within a predetermined area, a first processing means for processing the counting result of the counting means, and a first processing means. An image reading apparatus having a matching unit that pattern-matches the processing result of 1. and a determination unit that determines that the document is a specific document based on the result of the matching unit. 6. A first reading unit for reading visible information from a document, a second reading unit for reading information other than visible information from a document, and based on the information read by the first and second reading units. An image having a detection unit that detects the specific mark, a density detection unit that detects the density of the specific mark, and a determination unit that determines that the document is a specific document based on the detection result of the density detection unit. Reader. 7. A first reading unit for reading visible information from a document, a second reading unit for reading information other than visible information from a document, and based on the information read by the first and second reading units. An image having a detection means for detecting the specific mark, an array detection means for detecting the array of the specific marks, and a determination means for determining that the original is a specific original based on the detection result of the array detection means. Reader.