JPH06237362A - Picture processing unit - Google Patents

Abstract

PURPOSE:To add specific information specifying a copy source of a specific original in a visual observance disable state and to reproduce the specific information added to the specific original in a visually observance way. CONSTITUTION:Data specific to the unit are stored in advance in an LUT (lookup table) 110. After a picture signal from an image sensor 101 is converted into density data, data stored in the LUT 110 are added to a Y (yellow) signal in a picture signal by an adder circuit 109. Thus, the data specific to the unit are added to the picture signal and the resulting signal is outputted, and the data specific to the unit stored in the LUT 110 are data subjected to 2-dimensional discrete Fourier transformation.

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 having a function of detecting a specific original.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus includes a digital copying machine, an image reading apparatus, a facsimile apparatus, etc., and it has been considered desirable that any apparatus be capable of faithfully inputting a document. Therefore, when an image is input using a device of a type that handles information in the same manner, almost the same image data can be obtained even if the device is different.

[0003]

However, although it is originally desirable that the difference between individuals be small as described above, it is difficult to specify the device used for inputting an image. . You need to identify the device, for example, if you want to identify the sender on a fax machine, or if it is important what copy device the copy document was created on (such as a criminal investigation), or a security or For example, it is possible to find out the copy source of counterfeit goods such as banknotes. Hereinafter, a manuscript for which it is necessary to specify the device will be described as a specific manuscript.

Therefore, in recent years, a facsimile device or the like having a function of transmitting a sender name and the like in addition to an image signal has been proposed, but such a function can be changed by a user. Therefore, the additional information such as the sender's name is added in a human-readable format, so in some cases, it is possible to intentionally delete that part so that the original purpose cannot be achieved. It was Cases corresponding to this include a criminal purpose and a purpose of avoiding inconvenience caused by adding extra data other than the original image data.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and its purpose is to visually inspect information (hereinafter referred to as "specific information") for specifying the copy source of a specific document. An object of the present invention is to provide an image processing apparatus that can be added in a possible state and that can visually reproduce specific information added to a specific original.

[0006]

[Means for Solving the Problems]
In order to achieve the object, an image processing apparatus according to the present invention is an image processing apparatus for processing a multicolor image signal indicating a density, a storage unit that stores a predetermined signal in advance, and an input unit that inputs the image signal. And adding means for adding a predetermined signal stored in the storage means to the image signal input by the input means, and output means for outputting a result of the addition by the adding means. The predetermined signal is added to the image signal corresponding to one of the multiple colors.

[0007]

According to this structure, the storage means stores a predetermined signal in advance, the input means inputs the image signal, and the addition means stores the predetermined image signal input by the input means in the storage means. A signal is added, and the output means outputs the addition result of the addition means. In particular, the addition means adds a predetermined signal to the image signal corresponding to at least one of the multiple colors.

[0008]

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

<First Embodiment> FIG. 1 is a block diagram showing a first embodiment to which an image processing apparatus according to the present invention is applied. In the figure, the circuit configuration of the image processing portion of the digital color copying apparatus is shown. In the figure, 101 is an image sensor, 102 is an A / D converter, 103 is a shading correction circuit, 104 is a density conversion circuit, and 105 is a density conversion circuit.
Is a masking correction / UCR (undercolor removal) circuit, 106 is a selector, 107 is a γ correction circuit, 108 is a laser driver, 109 is an addition circuit, 110 is a LUT (lookup table), 111 is a main scanning counter, and 112 is a sub-scanning counter. Each of the scan counters is shown. Further, HSYNC indicates a horizontal synchronizing signal at the time of reading an image, and VCLK indicates an image clock in the vertical direction at the time of reading an image.

In the above structure, an optical signal obtained by relatively scanning the original enters the image sensor 101,
The intensity of light is converted into the intensity of an electric signal to generate a color-separated signal of three colors of red (R), green (G), and blue (B). This electric signal is converted from an analog signal to a digital signal by the A / D converter 102, and then the shading correction circuit 103 corrects the unevenness of the light amount in the optical system and the unevenness of the sensitivity of the image sensor. The signal is converted from light and dark to a signal showing the magnitude of density. The density signal thus obtained is subjected to masking correction / color conversion by the UCR circuit 105, and is also subjected to undercolor removal and blackening processing to obtain cyan (C), magenta (M), yellow (Y), black (BK). ) Signal of four colors. Each signal is sequentially selected by the selector 106, and an image is formed for each color. The selected signal is corrected for non-linearity in printing by the γ correction circuit 107, and then the semiconductor laser is driven by the laser driver 108 to form a latent image on a photosensitive drum (not shown) and copy output is performed. Only when the Y signal is formed, the signals read from the look-up table 110 are added by the adding circuit 109 to correct the image data. The lookup table 110 is the main scanning counter 11
1 and the sub-scanning counter 112. The main scanning counter 111 counts the image clock VCLK, and the sub-scanning counter 112 counts the horizontal synchronizing signal HSYNC by 7 bits each to generate a sub address signal.
12 bits in the main and sub-scanning directions
The pattern that is repeated every 8 × 128 pixels is LUT1
10 occurs.

The LUT 110 is a ROM (read-only memory), which stores a converted image pattern representing data unique to the device. FIG. 3 shows an example of the data stored in the LUT 110 before and after conversion. The one shown in FIG. 9A is a human-readable format before conversion, but this is a LUT.
Before being stored in 110, a two-dimensional discrete Fourier transform is performed, and when the pattern is unreadable by humans, it is transformed as shown in FIG. 2 for an M × N pixel image
The dimensional discrete Fourier transform is based on the following known equation (1). That is,

[0012]

[Equation 1] Becomes However, W1 = exp (-j2π / M), W2
= Exp (-j2π / N), and g (m, n) represents the (m, n) -th component of the original image data. The data G (k, l) obtained by this conversion is a representation format in the spatial frequency domain of the original image, and is completely different from the original data. Therefore, in general, the data G (k,
The contents of l) cannot be read visually.
Now, this data is stored in the LUT 110, and at the same time, it is added to the inconspicuous color Y (yellow) signal of the output colors so that it cannot be seen with the naked eye. Output) and a density that can be read using a sensor. In the copy output to which the information is added in this way, the added information cannot be visually inspected, but if the data G (m, n) is inversely converted after the data is read by the scanner (sensor) as necessary, the data is again reproduced. The original data g (m, n) can be obtained as an image that can be restored. The inverse transformation for returning to the original is shown by the following equation (2). That is,

[0013]

[Equation 2] Becomes However, W1 = exp (-j2π / M), W2
= Exp (-j2π / N). It goes without saying that this inverse transformation can be realized by using scanner and calculation means. When the inverse conversion is performed, the expression (2) is applied to the color-separated signal of the copy output image read by the scanner. At this time, the copy output image naturally overlaps the image of the copy original, and this original image acts as noise when extracting the additional information, but means for selecting a relatively flat image portion and the repetition period of the additional information. It is easy to restore the additional information to such an extent that the additional information can be discriminated by means such as averaging image data. This is because the inversely transformed original image is randomly distributed, but the inversely transformed additional information is reproduced as an image having meaning, which makes it easy to determine.

FIG. 4 is a side sectional view showing the structure of the main part of the digital full-color copying apparatus of this embodiment. In the figure, reference numeral 401 denotes an image scanner section, which is a section for reading a document and performing digital signal processing. The image scanner unit 401 has a configuration excluding the laser driver 108 shown in FIG. A printer unit 402 can print out image data corresponding to the original image read by the image scanner unit 401 on a recording sheet in full color.

In the image scanner unit 401, 40
Reference numeral 0 is a mirror surface plate. Document 45 on platen glass 403
1 is illuminated by the illumination lamp 452 and the mirrors 406, 4
It is guided to 07 and 408, and an image is formed on the image sensor 101 by the lens 409. As a result, the red (R), green (G), and blue (B) signal components of full-color information are sent to the signal processing unit 411. The image sensor 101 is a photoelectric conversion element (101-1, 101-2, 101) having three color filters of R, G, and B.
It is an argument that it is composed of -3).

Lamp 452 and mirror 406 are at velocity V
The mirrors 407 and 408 are at 1/2 V, and the image sensor 1
By mechanically moving in the direction perpendicular to the electric scanning direction of 01, the front surface of the original is scanned while always keeping the optical path length between the reading portion on the original 451 and the image sensor 101 constant. The signal processing unit 411 electrically processes the read signal, decomposes it into magenta (M), cyan (C), yellow (Y), and black (Bk) color components, and sends them to the printer unit 402. Further, one component of M, C, Y, and Bk is sent to the printer unit 402 for each document scanning (scanning) in the image scanning unit 401, and one printing is performed by scanning the document four times in total. Out is completed.

The M, C, Y and Bk image signals sent from the image scanner unit 401 are sent to the laser driver 108. The laser driver 108 modulates and drives the semiconductor laser 454 according to these image signals. The laser light is generated by the polygon mirror 414, the f-θ lens 415,
The photosensitive drum 417 is scanned via the mirror 416 to form an electrostatic latent image.

Reference numeral 418 denotes a rotary developing device, which includes a magenta developing section 418, a cyan developing section 420, and a yellow developing section 42.
1. The black developing unit 422 includes four developing units alternately contacting the photosensitive drum 417 to develop the electrostatic latent image formed on the photosensitive drum 417 with toner. Reference numeral 423 denotes a transfer drum, which winds the recording paper resting from the recording paper cassette 424 or 425 around the transfer drum 423, and transfers the image formed on the photosensitive drum 417 to the recording paper. After the four colors M, C, Y, and Bk are sequentially transferred in this manner, the recording paper passes through the fixing unit 426 and is ejected.

As described above, according to the first embodiment, when the image is output, the specific information of the input device such as the scanner and the facsimile device, which is the source of the original image, cannot be visually recognized. It is possible to add and output without trouble, and to reproduce the specific information in a visible state from the original image to which the specific information has already been added in an invisible state, and to easily identify the person or device involved in the crime. You can

<Second Embodiment> FIG. 2 is a block diagram showing a second embodiment to which the image processing apparatus according to the present invention is applied. In the figure, 201 is an image sensor, 202 is an A / D converter, 203 is a shading correction circuit,
204 is a density conversion circuit, 205 is a masking correction / UC
An R circuit, 209 is an adding circuit, 210 is an LUT, 211 is a main scanning counter, and 212 is a sub-scanning counter. The structure and function are the same as those of the first embodiment shown in FIG. The operation up to outputting is basically the same as that of the first embodiment described above, and therefore the description is omitted here. In addition, in the second embodiment, the following configuration is added to the configuration of FIG. That is, the CPU that controls the entire device
A ROM 213 stores programs for operating the CPU 213, and a RAM 215 used as a work area for various programs.

In particular, the LUT 210 is a RAM (readable / writable memory) in this embodiment, and has a structure in which additional information is written in advance prior to the image reading operation. This additional information includes auxiliary variable information such as date and time, the number of output sheets, and the data unique to the device is already written.

Next, the image processing procedure of the CPU 213 according to the second embodiment will be described with reference to FIG.

Prior to the reading of the original image by the image sensor 201, the CPU 213 reads the image data representing the device-specific information read from the ROM 214 (step 1), and adds a variable data portion if necessary (step 2). Based on this, the result calculated by the equation (1) is written in the LUT 210 (step 3). LUT
The information written in 210 is sequentially addressed by the main scanning counter 211 and the sub-scanning counter 212 as the image is read, and added by the adder circuit 209 to the Y signal to correct the image signal. By repeating this process, one page can be corrected, and as additional information, not only the data unique to the apparatus but also auxiliary variable information such as the date and time and the number of output sheets can be added to the image data at the same time.

The variable information may be arbitrarily selected by an operation unit (not shown), and whether the variable information is added or not may be arbitrarily selected.

<Third Embodiment> Now, the above first and second embodiments
In each of the embodiments, the data obtained by performing the two-dimensional discrete Fourier transform is added to the image signal. However, the conversion method is not limited to this, and any method capable of inverse conversion can be applied to the present invention. Of course, it can be applied. As an example, there may be mentioned a method in which the pixel blocks of the original data are regularly replaced and converted. Here, the size of the pixel block is 4 × 4 pixel units, but the size is not necessarily limited.

FIG. 5 is a diagram for explaining an example of a pixel block conversion method according to the third embodiment. Generally, the two-dimensional discrete Fourier transform has a large amount of calculation, but if the pixel blocks (Bi, j) are replaced, the amount of calculation is small.

Now, in the above-mentioned first to third embodiments,
Although the addition method is used as a method of adding the specific information to the image signal, the present invention is not limited to this, and for example, a method of multiplying the image signal by the signal of the specific information may be used.

First of all about the digital color copying apparatus
Although the third embodiment has been described, the present invention is not limited to a digital color copying apparatus, and an apparatus for inputting image data such as a scan scanner, an apparatus for transmitting image data such as a facsimile machine, etc. It can also be widely applied to.

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.

[0030]

As described above, according to the present invention,
When outputting an image, it is possible to add specific information such as the input device such as the scanner or the facsimile device, which is the source of the original image, in a non-visual state without any trouble and to output the specific information in an already invisible state. It is possible to reproduce the specific information in a visible state from the document image to which is added, and to easily identify the person or device involved in the crime.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment to which an image processing apparatus according to the present invention is applied.

FIG. 2 is a block diagram showing a second embodiment to which the image processing apparatus according to the present invention is applied.

FIG. 3 is a diagram illustrating a relationship between data before and after conversion of data stored in an LUT 110.

FIG. 4 is a side sectional view showing the configuration of the main part of the digital full-color copying apparatus of this embodiment.

FIG. 5 is a diagram illustrating an example of a pixel block conversion method according to a third embodiment.

FIG. 6 is a flowchart illustrating an image processing procedure of the CPU 213 according to the second embodiment.

[Explanation of symbols]

 101, 201 Image sensor 102, 202 A / D converter 103, 203 Shading correction circuit 104, 204 Density conversion circuit 105, 205 Masking / UCR circuit 106, 206 Selector 107, 207 γ correction circuit 108, 208 Laser driver 109 Addition circuit 110 , 210 LUT 110-1 to 110-3 CCD 111, 211 Main scanning counter 112, 212 Sub scanning counter 213 CPU 214 ROM 215 RAM 400 Mirror surface pressure plate 401 Image scanner section 402 Printer section 403 Platen 404 Original 405 Lamp 406, 407, 408 Mirror 409 Lens 410 3 line sensor 411 Signal processing unit 412 Laser driver 413 Semiconductor laser 414 Polygon mirror 415 f-θ lens 4 16 Mirror 417 Photosensitive drum 418 Rotational developing device 419 Magenta developing part 420 Cyan developing part 421 Yellow developing part 422 Black developing part 423 Transfer drum 424, 425 Paper cassette 426 Fixing unit

Claims (4)

[Claims] 1. An image processing apparatus for processing a multicolor image signal indicating density, a storage means for storing a predetermined signal in advance, an input means for inputting the image signal, and an image signal input by the input means. And an output unit for outputting a result of the addition of the addition unit, the addition unit corresponding to at least one of the multicolors. An image processing apparatus, wherein the predetermined signal is added to an image signal. 2. The image processing apparatus according to claim 1, wherein the predetermined signal is a signal which has been orthogonally transformed. 3. The image processing apparatus according to claim 2, wherein the orthogonal transform is a two-dimensional discrete Fourier transform. 4. The image processing apparatus according to claim 1, wherein the predetermined signal is a signal obtained by replacing image blocks.