JPH0514682A - Picture processing unit - Google Patents

Abstract

PURPOSE:To keep picture quality to a white/black reproduced picture in an excellent way even when a function adding a specific pattern to the reproduced picture is provided to the processing unit. CONSTITUTION:When an achromatic/chromatic color discrimination circuit 417 discriminates the input of a picture data of an achromatic (black/white) picture, a pattern addition circuit 410 does not add a pattern to the achromatic picture data to be inputted and outputs the result. On the other hand, when the achromatic/chromatic color discrimination circuit 417 discriminates the input of the picture data of the chromatic (color) picture, the pattern addition circuit 410 adds a pattern to the inputted chromatic picture data and outputs the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, for example, an image processing apparatus having a function of adding a specific pattern to a reproduced image.

[0002]

2. Description of the Related Art Conventionally, due to the high image quality and colorization of copying machines, specific documents such as securities and banknotes that should not be originally copied are copied with high image quality that is almost indistinguishable from the actual product and abused. There is a fear that it will be done.

Therefore, in an image reproducing apparatus such as a copying machine, it is difficult for the human eye to identify the information such as the number of the copying machine used for copying, the date of copying and the like, which specifies the copying machine used for the reproduced image. There is a method of solving the above problem by adding it as a pattern, which is useful for investigation when it is abused.

[0004]

However, in the above-mentioned conventional example, even in the black-and-white copy, the specific pattern is added, but since the specific originals that should not be copied are all chromatic, the black-and-white copy is performed. It is useless to add a specific pattern, in other words,
There was a drawback that the image quality deteriorated.

The present invention has been made in view of the above-mentioned conventional example, and an object thereof is to improve the image quality of a reproduced image even if the reproduced image has a function of adding a specific pattern. The point is to provide an image processing device that can be held.

[0006]

[Means for Solving the Problems]
In order to achieve the object, an image processing apparatus according to the present invention includes an input unit for inputting image data, a synthesizing unit for synthesizing a predetermined pattern with the image data input by the input unit,
Output means for outputting the image data obtained by the synthesizing means,
And a control unit for controlling execution / non-execution of the synthesizing unit according to the image data or the output mode of the output unit.

[0007]

According to this structure, the input means inputs the image data, the synthesizing means synthesizes a predetermined pattern with the image data input by the input means, and the output means outputs the image data obtained by the synthesizing means. The control means controls execution / non-execution of the synthesizing means according to the image data or the output mode of the output means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the following embodiments, an example of a copying machine is shown as an application example of the present invention, but the present invention is not limited to this, and it goes without saying that it can be applied to various other apparatuses. In addition, each device applicable to the present invention targets specific manuscripts such as banknotes, securities, and secret documents as anti-counterfeiting.

<First Embodiment> FIG. 2 is a side sectional view showing the structure of a copying machine according to the first embodiment of the present invention. In FIG. 2, reference numeral 201 denotes an image scanning portion, which is 400 dpi.
This is a part that reads a document at a resolution of (dots / inch) and performs digital signal processing. A printer unit 202 is a unit that outputs an image corresponding to the original image read by the image scanner 201 on a sheet in full color print at a resolution of 400 dpi.

In the image scanning unit 201, 20
Reference numeral 0 is a mirror pressure plate, which is a platen glass (hereinafter, platen).
A document 204 on 203 is illuminated by a lamp 205, guided to mirrors 206, 207, 208, and an image is formed on a 3-line sensor (hereinafter, CCD) 210 by a lens 209, and a full color information red (R) is formed. , Green (G), and blue (B) components are sent to the signal processing unit 211. The carriage 226 that fixes 205 and 206 is at a speed v, and the carriages 207 and 208 are at a speed of 1/2 v by mechanically moving in a direction perpendicular to the electrical scanning (main scanning) direction of the line sensor. Then, the entire surface of the document is scanned (sub-scanning).

In the signal processing unit 211, the read image signal is electrically processed and decomposed into magenta (M), cyan (C), yellow (Y) and black (Bk) components, and the printer unit. Send to 202. In addition, M, C, and
One component of Y and Bk is sent to the printer unit 202, and a total of four document scans completes one printout.

The M, C, Y, and Bk image signals sent from the image scanner unit 201 are supplied to the laser driver 2.
Sent to 12. The laser driver 212 modulates and drives the semiconductor laser 213 according to the sent image signal. The laser light scans the photosensitive drum 217 via the polygon mirror 214, the f-θ lens 215, and the mirror 216. Reference numeral 218 denotes a rotary developing device, which is a magenta developing unit 2
19, a cyan developing unit 220, a yellow developing unit 221, and a black developing unit 222. The four developing units alternately contact the photosensitive drum 217, and develop the latent image formed on the photosensitive drum with toner. Reference numeral 223 denotes a transfer drum, which winds the paper supplied from the paper cassette 224 or 225 around the transfer drum 223 and transfers the image developed on the photosensitive drum onto the paper.

In this manner, after the four colors M, C, Y and Bk are sequentially transferred, the sheet passes through the fixing unit 226, the toner is fixed on the sheet, and then the sheet is discharged.

[Image Scanner] FIG. 1 is a block diagram showing the structure of the image scanner 201 according to the first embodiment. In the figure, 210-1, 210-2,
210-3 is a CCD (solid-state image sensor) sensor having a spectral sensitivity characteristic of red (R), green (G), and blue (B), respectively, and outputs 8 bits 0 to 255 after being A / D converted. Signal is output.

In this embodiment, the sensor 21 used
Since 0-1, 210-2, and 210-3 are arranged with a constant distance, the delay elements 401 and 402 are arranged.
At, the spatial deviation is corrected.

Reference numerals 403, 404 and 405 are log converters, which are constituted by a look-up table ROM or RAM and convert the luminance signal into a density signal. 406 is a known masking and UCR (under color removal) circuit,
Although a detailed description is omitted, each of the input signals is used to sequentially output each signal of magenta (M), cyan (C), yellow (Y), and black (Bk) for output in a frame-sequential manner. It is output with a predetermined bit length, for example, 8 bits.

Reference numeral 407 is a known spatial filter circuit,
The spatial frequency of the output signal is corrected. A density conversion unit 408 corrects the density characteristics of the printer unit 202, and is composed of the same ROM or RAM as the log converters 403 to 405.

On the other hand, 414 is a microcomputer (hereinafter referred to as CPU) which controls the apparatus, and 415 is a CPU.
ROM storing a program for operating 414, 41
A RAM 6 is used as a work area for executing various programs. Reference numeral 413 is an input / output port (hereinafter, I / O port) connected to the CPU 414, and reference numeral 409 is a specific manuscript judgment circuit. Specific document determination circuit 409
Determines whether at least one of a plurality of specific originals is being read, and the determination signal H is output in multi-valued 2 bits. That is, if it is most likely that at least one of the plurality of specific documents is being read, H = “3” is output, and if the possibility is the least, H = “0” is output. To do. Further, the determination circuit 409
A thinning circuit 301 and a frequency dividing circuit 3 which will be described later with reference to FIG.
10 is also provided to perform decimation processing of the input R, G, B signals.

The CNO signal is a 2-bit frame sequential signal and is a control signal indicating the order of four reading operations.
FIG. 13 is a diagram showing the relationship between the CNO signal and the print output according to the first embodiment. The CNO signal is the CPU 414.
Generated via I / O port 413 and masked /
The operating conditions of the UCR circuit 406 are switched. Further, the CNO signal of the above-described frame sequential signal is also input to the determination circuit 409, and the determination reference can be switched for each of the four reading operations to determine different specific originals.

Reference numeral 410 denotes a pattern-impossible circuit, which is a CPU
2-bit pattern level selection signal P designated by 414
This is a portion for adding a pattern which is difficult for the human eye to recognize according to S. Reference numeral 417 denotes an achromatic color / chromatic color determination circuit, which has a function of prohibiting addition of a pattern by the pattern addition circuit 410 when it is determined to be an achromatic (black and white) copy.

[Timing Chart] FIG. 4 is a circuit diagram showing the configuration of the thinning circuit according to the first embodiment, and FIG. 5 is a circuit diagram showing the configuration of the frequency dividing circuit according to the first embodiment. FIG. 7 is a timing chart of signals in the main scanning direction in the first embodiment.

The VSYNC signal is a sub-scan section signal,
It is a signal indicating the image output section of the sub-scan. HSYNC
Is a main scanning synchronization signal, which is a signal for synchronizing the start of main scanning. CLK is an image transfer clock, and is a basic clock for various image processes in this embodiment.

On the other hand, CLK 'is obtained by dividing the CLK signal by 1/4 and serves as a basic clock in the decision circuit 409. The SEL signal is a timing signal used in the thinning circuit 301 described above, and is generated by the frequency dividing circuit 310 shown in FIG. 5, respectively. That is, the frequency dividing circuit 310
Is composed of an inverter 451, a bit counter 452, an inverter 453, and an AND gate 454. Two
The bit counter 452 displays HSY which is a main scanning synchronization signal.
After being cleared (initialized) by the NC signal, the CLK signal is counted and the count value is output in 2 bits (D0, D1). The upper bit D1 is output as the CLK4 signal, and the logical product of the inverted signal of the lower bit D0 and the upper bit D1 is output as the SEL signal.

As a result, in the thinning circuit 301 shown in FIG. 4, flip-flops 455, 456, 457 and 461, 462, 46 which hold data by the CLK signal.
3, selectors 458, 459, 460, flip-flops 464, 465, 4 for holding data by CLK 'signal
As shown in FIG. 7, the decimating circuit composed of 66 decimates the R (or G, B) signals transferred by the CLK signal at a rate of 1/4 to CLK ′. A synchronized R '(or G', B ') signal can be obtained.

[Determination Circuit] FIG. 3 is a block diagram showing the configuration of the determination circuit 409 according to the first embodiment. In the figure, reference numeral 301 denotes the thinning circuit shown in FIG. 4, which performs data thinning processing in order to reduce the possibility of the processing circuit of the determination circuit 409 itself. Reference numeral 302 denotes a color matching / lookup table ROM (hereinafter referred to as “color matching LUT”), which performs color matching with a plurality of types (specific securities, banknotes, etc.) of specific original documents prepared in advance. The tint matching LUT 302 holds the result of a determination as to whether or not the tint of the pixel matches the tint of the particular original document by examining the tint distribution of 32 types of specific original documents in advance.

That is, the tint matching LUT 302 includes
The CNO signal which is a frame sequential signal is input to the above 2 bits of the address, and the upper 5 bits of the image signal of each color of RGB which is thinned out to the lower 15 bits are input. Each CNO
When the signal value is 0 to 3, each pixel has a tint of 8
Whether or not it matches the tint of a particular type of original is simultaneously output in correspondence with 8-bit data, and a total of 32 types of specific originals are determined in four scanning scans.

303-1, 303-2, ..., 30
Reference numeral 3-8 denotes a tint determination circuit configured by the same hardware, which includes an integrator 306 and registers 307-1 and 3-3.
07-2 and 307-3 and a comparator module 308, each of which determines the possibility that a specific document exists in the document with two bits. A maximum value circuit 309 outputs the maximum value of the determination result outputs of the tint determination circuits 303-1 to 303-8. That is, the determination result of the most probable existence among the eight types of specific originals is output.

[Integrator] FIG. 6 is a block diagram showing the structure of the integrator 306 according to the first embodiment.
FIG. 4 is a diagram showing inputs and outputs of an integrator 306 according to the first embodiment. In FIG. 6, 501 and 505 are flip-flops that hold data at the rising timing of the CLK 'signal. 502 is a multiplier, which is 8 bits of 2
The input signal (A, B) is input and an 8-bit signal (A × B / 255) is output as the multiplication result. Reference numeral 503 is also a multiplier, which inputs a 1-bit input signal (A) and an 8-bit input signal (B) and outputs an 8-bit output signal (A × B) as a multiplication result. An adder 504 inputs an 8-bit 2-input signal (A, B) and outputs an 8-bit signal (A + B) as an addition result.

As a result, in the integrator 306, 2
The 8-bit output signal y _{i with} respect to the value input signal x _i is expressed by the following equation (1). That is,

[0030]

[Equation 1] Is. Here, α and β are preset constants, and the characteristics of the integrator 306 are determined by the magnitude of these values.

For example, in the case of α = 247 and β = 8, the output y _i as shown in FIG. 9 is output for the input x _i-1 as shown in FIG.

Here, an input that is "1" even though the periphery is almost "0" like the points 701 and 702, or the periphery is almost "1" like the point 703. Nevertheless, an input that is "0" is considered to be noise. This is processed by the integrator 306, and the register 307 of FIG. 3 stores 704-1 (R1 value) and 704-2 (R).
Noise can be removed by setting the threshold values indicated by the levels of (binary) and 704-3 (R3 value) and binarizing the output y _i of the integrator 306 with this.

[Comparator Module] FIG. 10 is a block diagram showing the configuration of the comparator module 310 according to the first embodiment. In the figure, 801, 802 and 803 are comparators, 804 is an inverter, 805 is an AND gate, 8
Reference numerals 06 and 807 denote OR gates, respectively. The register 307-1 has R1 and the register 307 described in FIG.
-2 is set to R2 described in FIG. 8, and the register 307-3 is set to the value R3 described in FIG. 8. R1> R2
> R3. With this configuration, as a result, the determination result is quantized into 2 bits and output.
That is, when R1 <(input), 11 is output, and when R2 <(input) ≦ R1, 10 is output, and R is
If 3 <(input) ≤ R2, 01 is output and (input)
If ≦ R3, 00 is output. [Pattern Adding Circuit] FIG. 11 is a block diagram showing the structure of the pattern adding circuit 410 according to the first embodiment, and FIG. 14 is a top view of the document table according to the first embodiment. Figure 1
1, 901 is a sub-scanning counter, 902 is a main scanning counter, 903 is a look-up table ROM (hereinafter referred to as "LUT"), 905 is a flip-flop, and 91.
3 is an AND gate, 906, 907, 908, 909 are registers, 910 is a 4to1 selector, 911, 913
Is an AND gate, and 912 is an adder. Here, the sub-scanning counter 901 repeatedly counts the main scanning synchronizing signal HSYNC, and the main scanning counter 902 repeatedly counts the pixel synchronizing signal CLK with a width of 9 bits, that is, 512 cycles.

Further, the LUT 903 is a read-only memory in which a pattern to be added is held, and the lower 6 bits of the count value of each of the sub-scanning counter 901 and the main scanning counter 902 are input. L
Only one bit is referenced for the output of UT903, and AND
The gate 904 ANDs the upper 3 bits of the main scanning counter 901 and the upper 3 bits of the sub-scanning counter 902.
The AND gate 913 is synchronized with the CLK signal in the flip-flop 905, and is ANDed with both the CNO signals “0” and “1” which are 2-bit field sequential signals in the AND gate 913. Sent to. This is a signal valid only when CNO = 2, that is, currently printed in yellow.

On the other hand, the registers 906, 907, 908,
The values P1, P2, P3 and P4 are held in advance in 909, and any one of P1 to P4 is selected in accordance with the pattern level selection signal PS designated by the CPU 414, and is passed through the AND gate 911. The adder 912 adds a pattern to the input signal V and outputs V ′. Therefore, when CNO = 2, that is, when printing is currently performed in yellow, the pattern held in the LUT 903 is repeatedly read and added to the signal to be output.

Here, P1 <P2 <P3 <P4 is set, and the selector 910 has Y = A when s = 00 (binary) and Y = B when s = 01 (binary). ,
When s = 10 (binary number), Y = C, and s = 11
Since it is set such that Y = D when (binary), V ′ = V + P1, P when PS = 00 (binary)
When S = 01 (binary number), V ′ = V + P2, PS = 1
When 0 (binary number), V ′ = V + P3 and PS =
When 11 (binary number), a pattern is added so that V ′ = V + P4.

Here, the pattern to be added is added only by the yellow toner so that it is difficult for the human eye to identify it. This is because the human eye distinguishes the pattern drawn by the yellow toner. It takes advantage of the weak ability. Furthermore, by changing the level of the pattern to be added depending on the possibility that a specific document exists in the input image,
In a normal copy, the pattern is made almost invisible to the human eye, and the stickiness and the pattern are added as the possibility that the specific document exists increases.

As described above, according to the first embodiment, in the case of monochrome copying, the image is reproduced without adding the pattern by the pattern adding circuit 410, so that the deterioration of the image quality can be prevented.

<Second Embodiment> In the first embodiment described above, the R.D. G. The addition / non-addition of the pattern is controlled based on the B signal, but the present invention is not limited to this, and image data (R.G.B signal) obtained from an external device such as a host computer.
Also in the above, the achromatic color or the chromatic color is determined, and when the color is determined to be the achromatic color, the pattern addition circuit may prevent the addition of the pattern because it is a monochrome copy. FIG. 12 is a block diagram showing the image processing system according to the second embodiment. In the figure, 1001 indicates an external device such as a host computer, 1003 indicates an image scanner, and 1004 indicates a printer. 1002 is a relay device,
Relay processing is performed between the external device 1001 and the printer 1004 (image scanner 1003), and at the same time, the determination circuit 409, the achromatic / chromatic color determination circuit 417, the pattern addition circuit 410, I / I described in the first embodiment. O413, C
It has the same configuration as the PU 414, the ROM 415, and the RAM 416.

The operation of the above system will be described.

Upon receiving the image signal of the external device 1001, the relay device 1002 checks the ratio of the RGB components of the image signal, and if the ratio is 1: 1: 1, the received image signal corresponds to a monochrome image. It is judged and sent to the printer 1004 without adding a pattern by the pattern adding circuit.

<Third Embodiment> In the first and second embodiments described above, no pattern is added only in the case of black-and-white copying. Even when the copy mode or the two-color copy mode is designated, the control may be performed without adding the specific pattern.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus. The image output means is not limited to the laser beam printer as described above, and an inkjet printer, a thermal transfer printer or the like may be used. Also, a point-sequential output means may be used instead of the frame-sequential method. Further, the input means is not limited to an image reader of a type in which a document is scanned by a CCD sensor, but a host computer, a video camera, a still video camera,
You may use the film reader etc. which read a color film.

[0044]

As described above, according to the present invention, the image quality of a reproduced image can be kept good even if it has a function of adding a specific pattern to the reproduced image.

[Brief description of drawings]

FIG. 1 is an image scanning unit 201 according to a first embodiment.
3 is a block diagram showing the configuration of FIG.

FIG. 2 is a side sectional view showing the configuration of the copying machine according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a determination circuit 409 according to the first embodiment.

FIG. 4 is a circuit diagram showing a configuration of a thinning circuit according to the first embodiment.

FIG. 5 is a circuit diagram showing a configuration of a frequency dividing circuit according to a first example.

FIG. 6 is a block diagram showing the configuration of an integrator 306 according to the first embodiment.

FIG. 7 is a timing chart of signals in the main scanning direction in the first embodiment.

FIG. 8 is a diagram showing inputs and outputs of an integrator 306 according to the first embodiment.

FIG. 9 is a diagram showing inputs and outputs of an integrator 306 according to the first embodiment.

FIG. 10 is a comparator module 310 according to the first embodiment.
3 is a block diagram showing the configuration of FIG.

FIG. 11 is a pattern adding circuit 410 according to the first embodiment.
3 is a block diagram showing the configuration of FIG.

FIG. 12 is a configuration diagram showing an image processing system according to a second embodiment.

FIG. 13 is a diagram showing a relationship between a CNO signal and print output according to the first embodiment.

[Explanation of symbols]

Reference numeral 200 Mirror surface pressure plate 201 Image scanner section 202 Printer section 203 Platen 204,801 Original document 205 Lamps 206,207,208 Mirror 209 Lens 210 3 line sensor 211 Signal processing section 212 Laser driver 213 Semiconductor laser 214 Polygon mirror 215 f-θ lens 216 Mirror 217 Photosensitive drum 218 Rotating developing unit 219 Magenta developing unit 220 Cyan developing unit 221 Yellow developing unit 222 Black developing unit 223 Transfer drums 224, 225 Paper cassette 226 Fixing unit 210-1 to 210-3 CCD 301 Thinning circuit 302 Color matching LUT, 303-1 to 303-8 Color determination circuit 307-1 to 307-3 Register 308 Comparator module 309 Maximum value circuit 310 Dividing circuit 401, 402 Delay element Child 403 to 405 log converter 406 Masking / UCR circuit 407 Spatial filter 408 Density conversion circuit 409 Judgment circuit 410 Pattern addition circuit 413 I / O 414 CPU 415 ROM 416 RAM 417 Achromatic chromatic color judgment circuit 451, 453, 804 Inverter 452 2 bit counters 454, 805, 911, 913 AND gates 455-457, 461-466, 501, 505 Flip-flops 458-460, 910 Selectors 502, 503 Multipliers 504, 912 Adders 801, 802, 803 Comparators 806, 807 OR gate 901 Sub-scanning counter 902 Main-scanning counter 903 LUT 905 Flip-flop 906, 907, 908, 909 Register 1001 External device 1002 Relay device 1003 Images Jana 1004 printer

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 21/00 6605-2H G06F 15/62 410 Z 9287-5L

Claims (6)

[Claims] 1. An input unit for inputting image data, a synthesizing unit for synthesizing a predetermined pattern with the image data input by the input unit, an output unit for outputting the image data obtained by the synthesizing unit, and the synthesizing unit. An image processing apparatus, comprising: a control unit that controls execution / non-execution of the unit according to the image data or the output mode of the output unit. 2. The image processing apparatus according to claim 1, wherein the input means includes an external input means for inputting the image data from an external device. 3. The image processing apparatus according to claim 1, wherein the input unit includes a reading unit that reads a document and inputs the image data. 4. The image according to claim 1, wherein said control means controls said synthesizing means to be non-executed when said output means is set to a mode for outputting achromatic image data. Processing equipment. 5. The image processing apparatus according to claim 1, wherein said control means controls said synthesizing means to be non-executed when achromatic image data is inputted by said input means. 6. The image processing apparatus according to claim 1, wherein the output means is an image forming means for forming a visible image based on the image data obtained by the synthesizing means.