JPH0962158A - Image processing device - Google Patents

Abstract

(57) [Summary] [Purpose] When adding information for identifying a copying machine, etc. to the reproduced image of the original image, an image in which a different inconspicuous pattern can be added to each device without changing the quality of the reproduced image. An object is to provide a processing device. A device recognition pattern generation unit 44 that generates a device recognition pattern, and an input image signal that is an image signal of a predetermined gradation depending on whether the device recognition pattern generated by the device recognition pattern generation unit 44 is added or not. Tone reproduction circuits 39, 40, 42, 43 for converting to and outputting
The pattern switching generation unit 41 switches the gradation of the image signal output from each of 9, 40, 42, and 43 depending on whether to add the device recognition pattern generated by the device recognition pattern generation unit 44.

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 capable of adding specific information to a reproduced image while keeping the reproduced image of high quality.

[0002]

2. Description of the Related Art In recent years, color copiers and color printers have been improved in performance so that high-quality color copiers can be obtained. Such a high image quality color copying technique may be illegally used, for example, for copying a counterfeit bill. Heretofore, it has been a difficult task to identify which device copied an illegally copied copy. In order to prevent such illegal copying, it is considered to identify illegality by a color copying machine or color printer itself and forcibly prohibit illegal copying. In this case, a circuit for determining a specific document is used in a color copying machine or a color printer, but since the number of image patterns that can be registered in this determination circuit is limited, it is not possible to register all types of specific documents. It has the drawback of being impossible. Although it is important to add a means for detecting a specific document to the image copying apparatus itself, since the detection capability for the specific document is limited as described above, a document that should not be copied is not copied. In this case, it is important to identify the copying machine used for copying or the person who copied it. Based on such a background, a technique of adding information or the like that can identify a copying machine used for copying to a document image has been studied. The technique is to use an output color component (for example, yellow) that is the least noticeable to human eyes among the output color components (for example, magenta, cyan, yellow, and black) of the copying machine, and to generate an image signal of the output color component. The number is modulated (for example, by adding a constant value to the image signal), a number or code indicating the serial number of the copying machine, a dot formed by patterning the number, or the like is struck small and repeated at regular intervals.

However, even if yellow is the output color component that is the least visible, modulating the image signal means changing the color component, resulting in changing the color of the reproduced image. For example, when a color copying machine is used for design purposes, if a pattern that is not present in the original document is visible, the design may change slightly. When copying an original, even if the original has a uniform color, the image signal is not always uniform due to variations in the sensitivity of the CCD, etc. To print out C
Since it is possible to directly output G (computer graphics), there is sufficient uniform area at the image signal level. When the yellow component is modulated with respect to such an image signal, the additional pattern tends to be conspicuous particularly in a light gray or light blue uniform portion, and the pattern is added even in the area where the image signal does not exist. There is a possibility that the additional pattern will stand out, and the toner consumption amount for only yellow will increase. As a conventional method, there is a method of forming a unit pattern in which numbers, signs, and dot patterns representing additional information are small, and repeating the unit pattern at regular intervals. When the unit patterns arranged in a small shape are arranged, the human eye can easily recognize a regular pattern rather than a randomly arranged pattern, so that it becomes more noticeable. In order to prevent this, there is no choice but to reduce the degree of modulation of the image signal, and the additional information may not be read depending on the specific document.
FIG. 9 is a copy diagram showing a copy result in the conventional image processing apparatus, and S1 is a copy image area.

[0004]

However, in the conventional image processing apparatus, as shown in FIG. 9, since a fixed amount of pattern is always added, even in the area where the copy image other than the copy image area S1 does not exist. There is a problem that the additional pattern is printed, and the quality of the reproduced image cannot be maintained because the pattern is added in a fixed amount. Therefore, it is difficult to identify the output image with the eyes of the human being while maintaining the quality of the original image in the reproduced image, and it is possible to reliably identify the copy such as the specific original document by some method. It was necessary to consider the gradation modulation and additional patterns that would satisfy the requirements.

The present invention solves the above-mentioned conventional problems. When information for identifying a copying machine or the like is added to a reproduced image of an original image, the image quality of the reproduced image is not changed.
An object of the present invention is to provide an image processing device that can add a different inconspicuous pattern for each device.

[0006]

In order to achieve this object, an image processing apparatus according to a first aspect of the present invention has an apparatus recognition pattern generating means for generating an apparatus recognition pattern and a device recognition pattern generating means for generating the apparatus recognition pattern. And a device recognition pattern is added, a gradation reproducing unit that converts an input image signal into an image signal having a predetermined gradation and outputs the image signal, and a gradation of the image signal output by the gradation reproducing unit. And a pattern switching generation means for switching depending on whether or not the device recognition pattern generated by the recognition pattern generation means is added.

An image processing apparatus according to a second aspect is the image processing apparatus according to the first aspect.
In the image processing apparatus described above, the gradation reproducing means comprises one additional dot as a single region of the device recognition pattern to be added, and is made up of a plurality of pixels, and the device recognition pattern to be added is identified by the difference in dot growth in the plurality of pixels. It has a configuration.

[0008]

With this configuration, the input image signal is converted into an image signal of a predetermined gradation depending on whether or not the device recognition pattern is added. Therefore, when the device recognition pattern is not added, the gradation is changed. It is possible to perform an image reproduction process with good characteristics and perform a gradation image reproduction process that is inconspicuous when a device recognition pattern is added but that can be surely identified by appraisal. This makes it possible to add a device recognition pattern that cannot be easily recognized by the human eye while maintaining the image quality of the original image in the reproduced image.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an image copying apparatus according to an embodiment of the present invention. In FIG. 1, 1 is 300 dp
An image scanner unit 2 that reads an original document at a resolution of i (dot / inch) and performs digital signal processing prints an image corresponding to the original document image read by the image scanner unit 1 on a sheet at a resolution of 300 dpi in full color. Printer unit, 3 is a mirror surface pressure plate that presses the original document 5 on the original platen glass 4, 6 is a lamp that illuminates the original document 5, 7, 8 and 9 are mirrors that guide the reflected light from the original document 5, and 10 is the original document 5 The lens 10 for focusing the image of the image is formed by the lens 10, and the image is used as a component of red (R), green (G), and blue (B) of full color information in a signal processing unit 12 described later. The three line sensors (CCD) and 12 for sending electrically process the image signal read by the CCD 11, and magenta (M), cyan (C), and yellow (Y). , A signal processing unit that decomposes each component of black (Bk) and sends it to the printer unit 2, 13 is a printer video processing unit that modulates and drives the semiconductor laser 14 according to the sent image signal, and 15 is a series of peripheral units. A rotating member having a flat reflecting surface, which is a polygon mirror for reflecting light from a light source onto an object, and 16 is an f-θ lens provided so that the light source reflected by the polygon mirror 15 irradiates the surface of the photoconductor at equal intervals. Reference numeral 17 denotes a mirror for reflecting the light source from the f-θ lens 16 to the photosensitive member, 18 denotes a photosensitive drum that is charged according to the laser light from the semiconductor laser 14, 19
Is a rotary developing device for developing the electrostatic latent image on the photosensitive drum 18,
Reference numeral 20 is a magenta developing portion of the rotary developing device 19, 21 is a cyan developing portion of the rotary developing device 19, 22 is a yellow developing portion of the rotary developing device 19, 23 is a black developing portion of the rotary developing device 19,
Reference numeral 24 is a transfer drum on which the development on the photosensitive drum 18 is transferred, 25 is a paper cassette for supplying paper, and 26 is a fixing unit for fixing toner to the paper.

The operation of the image copying apparatus configured as described above will be described. The lamp 6 and the mirror 7 that constitute the image scanner unit 1 are line sensors (CCD) 1
1 mechanically moves at a speed v in a direction (sub-scanning direction) perpendicular to the electrical scanning direction (main-scanning direction) of the mirrors 8, 9
Moves in the sub-scanning direction at a speed of v / 2. As a result, the entire surface of the original is scanned. The image read by scanning the entire surface of the document is sent to the signal processing unit 12 as red (R), green (G), and blue (B) components. Signal processing unit 12
Electrically processes an image signal composed of R, G, and B, decomposes it into magenta (M), cyan (C), yellow (Y), and black (Bk) components, and prints them on the printer video of the printer unit 2. It is sent to the processing unit 13. Printer video processing unit 13
Modulates and drives the semiconductor laser 14 according to the image signal sent, and the semiconductor laser 14 emits laser light according to the drive image signal from the printer video processing unit 13.
Laser light emitted from the semiconductor laser 14 passes through a polygon mirror 15, an f-θ lens 16, and a mirror 17,
The photosensitive drum 18 is scanned. As a result, the photosensitive drum 1
An electrostatic latent image corresponding to the laser beam is formed on the surface 8. The four developing portions of the rotary developing device 19 alternately contact the photosensitive drum 18, and develop the electrostatic latent image formed on the photosensitive drum 18 with four kinds of toner. The transfer drum 24 around which the paper supplied from the paper cassette 25 is wrapped around the peripheral surface is the photosensitive drum 18.
The image developed above is transferred to a sheet. The sheet on which the four colors M, C, Y, and Bk have been sequentially transferred in this manner passes through the fixing unit 26, and the toner is fixed. After fixing, the paper is ejected.

FIG. 2 shows a CCD 1 which constitutes the apparatus shown in FIG.
1 is a block diagram showing a signal processing unit 12. In FIG. 2, 27 is a CCD having spectral sensitivity characteristics of R, G, and B.
(Same as CCD 11 in FIG. 1), 28 is S / H (Samp
le Hold) conversion and analog / digital conversion S / H & A / D circuit, 29 is a shading correction circuit for correcting image shading, 30 is a LOG conversion circuit for converting a luminance signal to a density signal, 31 is R,
A masking / UCR (under color removal) circuit for inputting G and B signals and outputting M, C, Y and Bk signals, 32 a γ correction circuit composed of ROM or RAM and its peripheral circuits, and 33 an edge MTF (Modulat) that emphasizes
ion transfer function correction circuit, 34 is a pattern switching generation circuit that controls gradation reproduction in a reproduced image, and 35 is a gradation reproduction circuit (gradation reproducing means) that reproduces gradation in the reproduced image.

The operation of the signal processing section 12 of the image scanner section 1 configured as described above will be described.
The S / H & A / D circuit 28 connects the CCD 27 with R, G, and B.
Image signal is input, S / H and A / D converted, and output as 8-bit (0-255) R, G and B signals. The shading correction circuit 29 uses S / H & A /
Shading correction and black correction are performed on the R, G, and B signals from the D circuit 28, and the signals are output to the LOG conversion circuit 30. The LOG conversion circuit 30 outputs the shading correction circuit 29.
The R, G, and B signals output from are converted from a luminance signal to a density signal. Masking / UCR circuit 31
Inputs the R, G, B density signals from the LOG conversion circuit 30, and outputs the M, C, Y, Bk signals in a predetermined bit length in a frame sequential manner for each R, G, B reading operation (for example, (8 bits)
To output. The γ correction circuit 32 performs luminance correction on each of the M, C, Y, and Bk signals. Brightness corrected M, C,
The MTF correction circuit 33 to which the Y and Bk signals have been input performs edge enhancement or smoothing processing on these signals. The pattern switching generation circuit 34 switches the gradation reproduction processing for each of the M, C, Y, and Bk signals input from the MTF correction circuit 33. There are two gradation reproduction processes, one-dot gradation conversion and two-dot gradation conversion. The gradation reproduction circuit 35 performs the gradation conversion on the image signal based on the switching signal from the pattern switching generation circuit 34, outputs a reproduced image (reproduced image) in which the original image is reproduced with high quality, and outputs the apparatus. A device recognition pattern peculiar to is added to the reproduced image.

FIG. 3 is a block diagram showing the printer video processing unit 13 which constitutes the apparatus of FIG. In FIG. 3, 36 is a D / A converter that performs digital / analog conversion, 37 is a PWM circuit that performs pulse width modulation (PWM) according to the input signal, and 38 is the semiconductor laser 14 (see FIG. 1) according to the input signal. ) Is a laser driver.

The operation of the printer video processing unit 13 configured as described above will be described. Signal processing unit 1
M, C, Y, Bk output from the second gradation reproduction circuit 35
Each signal is converted into an analog signal by the D / A converter 36, and this analog signal is input to the PWM circuit 37. The PWM circuit 37 performs pulse width modulation (PWM) on the analog signal and outputs it to the laser driver 38. The laser driver 38 sends M, which is sent from the PWM circuit 37,
The semiconductor laser 14 is driven according to the C, Y, and Bk image signals, and the semiconductor laser 14 emits laser light according to the drive signal. The laser light emitted from the semiconductor laser 14 is passed through the optical systems 15, 16 and 17 to the photosensitive drum 18
Scan over. The subsequent operation is as described in FIG. In this way, a device-specific device recognition pattern that is a dot pattern that cannot be recognized by the human eye but can be reliably read using a specific recognition technology (such as a technology that recognizes with a magnifying glass or a signal processing) is used. Printed paper can be output.

FIG. 4 is a block diagram showing the pattern switching generation circuit 34 and the gradation reproduction circuit 35 of the signal processing unit 12 of FIG. In FIG. 4, 39 is a horizontal synchronizing signal generating circuit for generating a horizontal synchronizing signal at a predetermined time interval included in gradation processing, and 40 is a horizontal synchronizing signal counting circuit 2.
A binary counter, 41 is a pattern switching generating section (pattern switching generating means) for generating a switching signal according to a device recognition pattern peculiar to the apparatus, and 42 is a binary counter 40 and a pattern switching generating section 41. An inversion circuit that outputs a signal, 43 is a gradation conversion table unit that stores the pixel signal level after gradation conversion in the gradation conversion table memory,
A device recognition pattern generation unit (device recognition pattern generation means) 44 generates a device recognition pattern unique to the device. In FIG. 4, the horizontal synchronizing signal generating circuit 39, the pattern switching generating section 41 and the device recognition pattern generating section 44 constitute the pattern switching generating circuit 34 of FIG.
0, the inversion circuit 42, and the gradation conversion table unit 43 form a gradation reproduction circuit 35.

The operation of the pattern switching generation circuit 34 and the gradation reproduction circuit 35 configured as described above will be described. As the horizontal synchronizing signal generating circuit 39, for example, in the case of an LBP (laser beam printer), a circuit for performing waveform shaping on the beam detect signal of the polygon mirror 15 may be used. The binary counter 40 counts the horizontal synchronizing signal output from the horizontal synchronizing signal generating circuit 39, and switches the output signal level between ON and OFF each time the horizontal synchronizing signal is input. It indicates that the image signal to be displayed is an even line, and when it is off, it is an odd line. Pattern switching generator 4
Similarly to the binary counter 40, 1 also counts the horizontal synchronizing signal to determine whether it is an even line or an odd line, inputs pattern additional information from the device recognition pattern generation unit 44, and outputs a switching signal according to the pattern. The inversion circuit 42 outputs an off signal (low level signal) regardless of whether the signal output from the binary counter 40 is on or off when the output signal of the pattern switching generator 41 is an on signal (high level signal). Output. The gradation conversion table section 43 inputs the input image signal a, the output signal of the inverting circuit 42, and the switching signal of the pattern switching generating section 41, and uses these signals as memory addresses. That is, the gradation conversion table memory of the gradation conversion table unit 43 stores the pixel signal level using the above signals as memory addresses, and the pixel signal level is the pixel of the reproduced image (output image) b after gradation conversion. Signal level. The memory address line of the gradation conversion table memory is composed of 10 bits, of which the lower 8 bits are allocated to the image signal a, the 9th bit is the output signal of the inverting circuit 42, and the 10th bit is the pattern switching generator 41. It is assigned to the switching signal and a total of 768 gradation conversion table memories are accessed.

When the output signal (switching signal) of the pattern switching generator 41 is off, the output signal of the inverting circuit 42 is 2
It is the same as the output signal of the advance counter 40, and is an ON signal for even lines and an OFF signal for odd lines. The gradation conversion table unit 43 is 00h to FFh when the output signal of the inverting circuit 42 is an ON signal (even line).
The gradation conversion table memory address is acquired, and in the case of an off signal (odd line), the gradation conversion table memory address of 100h to 1FFh is acquired. Further, in the gradation conversion table unit 43, when the output signal of the pattern switching generation unit 41 is an ON signal, the output signal of the inverting circuit 42 is always an OFF signal as described above, and the gradation conversion table memory of 200h to 2FFh is used. Get the address.

Regarding the above gradation conversion table, FIG. 5 and FIG.
This will be described in detail with reference to FIG. FIG. 5 is a table showing the contents of the gradation conversion table, and FIGS. 6A and 6B are graphs showing the characteristics of the gradation conversion table. Input image signal a 8
Assuming that there are bits (256 levels), 256 addresses are required in the gradation conversion table to represent one gradation characteristic. In the present embodiment, there are two processes, a two-dot gradation reproduction process having two gradation characteristics of even lines and an odd line, and a one-dot gradation reproduction process having one gradation characteristic for all lines. It has a total of 768 gradation conversion table memory addresses by using gradation reproduction processing in combination. As shown in FIG. 5A, addresses 00h to F
The contents of the Fh gradation conversion table represent the gradation characteristics of even lines using 2-dot gradation reproduction.
The contents of the gradation conversion table of 1FFh represent the gradation characteristics of odd lines using 2-dot gradation reproduction. Further, as shown in FIG. 5B, the contents of the gradation conversion table at addresses 200h to 2FFh represent gradation characteristics using 1-dot gradation reproduction.

FIGS. 6A and 6B are graphs showing the gradation conversion table characteristics of 1-dot gradation reproduction and 2-dot gradation reproduction. In the 2-dot gradation modulation table characteristic of FIG. 6A, when the image density is low, the pixels of the odd lines are not printed, but the size of the pixels of the even line is adjusted (by area gradation). The gradation is reproduced, and when the image density is high, the dots of the pixels of the even lines maintain a certain level below the maximum output, and the gradation of the pixels of the odd lines is adjusted to reproduce the gradation. In other words, the priority is set for the two pixels of the odd line and the even line, the pixels of the even line are prioritized to grow the recording dots, and the dots of the even line are prevented from completely growing. Set the gradation conversion table characteristics. In an electrophotographic printer, it is better to preferentially grow dots of specific pixels than to uniformly grow dots of each pixel.
8 (see FIG. 1), a strong electric field is generated in the micro area of the electrostatic latent image, and the gradation of the recorded image is improved.

On the other hand, the 1-dot gradation conversion table characteristic is
The same gradation is reproduced in all lines of the input pixel level. In the present embodiment, when a high-quality image is reproduced by an image reproduction process with good gradation using a normal 2-dot gradation conversion for the input image signal a, and a device recognition pattern for recognizing a device is added. Only, the pattern switching generation circuit 34 performs the image reproduction process which does not give priority to the even / odd lines using the 1-dot gradation conversion. Therefore, the device recognition pattern can be added to the reproduction image without superimposing the image for the new addition pattern on the reproduction image (reproduction image).

FIG. 7 is a pattern configuration diagram showing the configuration of the additional pattern in this embodiment. The gradation reproduction circuit 35 of FIG. 2 switches the gradation reproduction processing based on the switching signal of the pattern switching generation circuit 34, and adds a dot pattern for recognizing the device in the 8 × 8 area shown in FIG. . One additional dot (single area) of the dot pattern consists of 4 pixels, as shown in FIG.
By using two gradation reproduction processes of dots, a pattern is added by utilizing the difference in density growth in one pixel. The shaded area in the 8 × 8 area indicating the image level is a portion where normal image reproduction processing with good gradation is performed by giving priority to even / odd lines by 2-dot gradation modulation.
Dots grow from even lines according to the priority. The black pattern-added portion in the 8 × 8 area indicating the image level is a portion where the image reproduction processing of the same level is performed on all lines by the 1-dot gradation modulation, and dots are uniformly grown. The difference in dot growth in these four pixels can be recognized as a pattern. That is,
The gradation of all the pixels is "80" as shown in FIG. 7, but in the normal image reproduction part, the gradation of the even line pixels shown by 2-dot gradation modulation is "40" and the even line priority is given. Reproduction processing is performed, and in the pattern-added portion, reproduction processing is performed evenly for each line in which the gradation of pixels in each line indicated by 1-dot gradation modulation is set to "20". The additional pattern (device recognition pattern) is a pattern obtained by encoding a serial number unique to the device, and the copied device can be limited by appraising the copied product (for example, magnifying glass, signal processing, etc.). it can.

FIG. 8 is a copy diagram showing an example of the copy result in this embodiment. In FIG. 8, S2 is a copy image area.

As described above, this embodiment does not newly add an additional pattern, but changes the growth of dots that reproduce an image by switching and using two gradation modulation processes for the input image signal a. Since the pattern is added in the area S, the area where the input image signal does not exist (area S
No pattern is added in areas other than 2) and an additional pattern is formed according to the image signal level (the above-mentioned "80" value differs depending on the input image signal level). It is possible to reproduce without impairing the gradation. In addition, although inconspicuous yellow is used in the conventional additional pattern, by switching between the two gradation reproduction processes according to this embodiment,
Patterns can be similarly added to the other three colors (cyan, magenta, and black). Further, in the present embodiment, the additional pattern is formed by switching between the two gradation reproduction processes, but the present invention is not limited to this, and even one (for example, 2-dot gradation modulation). Line priority may be inverted when a pattern is added) or a combination of several types. Further, the priority of the dot growth of the additional pattern is not limited to the even / odd lines, and it is needless to say that it is applied to the dot growth in which the priority is set not only on the sub-scanning side but also on the main-scanning side. Is. Further, although an electrophotographic printer using a laser beam printer has been described as an example in the present embodiment, the present invention is not limited to this, and an inkjet printer, a thermal transfer printer, an LED
It can be applied to a printer and is not limited to a color printer. In particular, a so-called bubble jet type printer using a head that discharges liquid droplets using film boiling due to thermal energy may be used. Further, although the original image is input by the image scanner unit 1 in the above-described embodiment, the present invention is not limited to this, and the still video camera, the one input by the video camera, and the computer graphics are used. It may be something. Furthermore, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device, and signal processing is achieved by supplying a program to the system or the device. It goes without saying that it can be applied to cases. Further, although the present embodiment has described the device recognition pattern, when a person uses the device with a card, the personal recognition pattern may be registered in the card and the registered pattern may be added to the image. This makes it possible to prevent banknote forgery by an individual, for example.

As described above, according to this embodiment, two gradation modulation processes are switched and used for the input image signal,
A pattern is added by changing the growth of the dots that reproduce the image, and the size of the dots is made to correspond to the input image signal level. The tone modulation process can be performed, and in the image reproduction process of the additional pattern part, the tone modulation process that can be distinguished from the normal image reproduction process part can be performed. Possible device recognition patterns can be added.

[0026]

As described above, according to the present invention, the device recognition pattern generating means for generating the device recognition pattern and the input image signal depending on whether the device recognition pattern generated by the device recognition pattern generating means are added or not. Whether to add the tone reproduction means for converting and outputting the image signal of a predetermined tone and the device recognition pattern generated by the device recognition pattern generation means for the tone of the image signal output by the tone reproduction means. By having a pattern switching generation means for switching according to whether or not the device recognition pattern is added, image reproduction processing with good gradation is performed, and when the device recognition pattern is added, it is inconspicuous but surely identified by appraisal. It is possible to perform image reproduction processing with possible gradation, and therefore it is not easy for the human eye to easily recognize the quality of the original image in the reproduced image. It is possible to reproduce an image processing apparatus capable of adding a location recognition pattern.

Further, the gradation reproducing means configures a single area of the device recognition pattern to be added from a plurality of pixels, and identifies the device recognition pattern to be added due to the difference in dot growth in the plurality of pixels, so that a normal image reproduction is performed. Since the gradation modulation processing with good gradation can be performed in the processing, and the gradation modulation processing that can be distinguished from the normal image reproduction processing portion can be performed in the image reproduction processing of the additional pattern portion, the gradation characteristics of the reproduced image can be improved. It is possible to reproduce an image processing device capable of adding a device recognition pattern that cannot be recognized by the human eye without damaging the image processing device.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an image copying apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a CCD and a signal processing unit which compose the apparatus shown in FIG.

3 is a block diagram showing a printer video processing unit which constitutes the apparatus of FIG.

FIG. 4 is a block diagram showing a pattern switching generation circuit and a gradation reproduction circuit of the signal processing unit of FIG.

FIG. 5 is a table diagram showing the contents of a gradation conversion table.

FIG. 6A is a graph showing a gradation conversion table characteristic, and FIG. 6B is a graph showing a gradation conversion table characteristic.

FIG. 7 is a pattern configuration diagram showing a configuration of an additional pattern in the present embodiment.

FIG. 8 is a copy diagram showing an example of a copy result in this embodiment.

FIG. 9 is a copy diagram showing an example of a copy result in a conventional image processing apparatus.

[Explanation of symbols]

1 Image Scanner Section 2 Printer Section 3 Mirror Surface Plate 4 Original Plate Glass 5 Original 6 Lamp 7 to 9, 17 Mirror 10 Lens 11, 27 CCD 12 Signal Processing Section 13 Printer Video Processing Section 14 Semiconductor Laser 15 Polygon Mirror 16 f-θ Lens 18 Photosensitive Drum 19 Rotating Developing Device 20 Magenta Developing Section 21 Cyan Developing Section 22 Yellow Developing Section 23 Black Developing Section 24 Transfer Drum 25 Paper Cassette 26 Fixing Unit 28 S / H & A / D Circuit 29 Shading Correction Circuit 30 LOG Conversion Circuit 31 Masking / UCR circuit 32 γ correction circuit 33 MTF correction circuit 34 pattern switching generation circuit 35 gradation reproduction circuit (gradation reproduction means) 36 D / A converter 37 PWM circuit 38 laser driver 39 horizontal synchronization signal generation circuit 40 binary counter 41 Pattern switching generation unit (pattern switching generation unit) 42 Inversion circuit 43 Gradation conversion table unit 44 Device recognition pattern generation unit (Device recognition pattern generation unit)

Claims (2)

[Claims] 1. A device recognition pattern generating means for generating a device recognition pattern, and an input image signal of a predetermined gradation depending on whether or not to add the device recognition pattern generated by the device recognition pattern generating means. Whether to add the tone reproduction means for converting into an image signal and outputting the tone of the image signal output by the tone reproduction means and the device recognition pattern generated by the device recognition pattern generation means; An image processing apparatus, comprising: a pattern switching generation unit that switches in accordance with the above. 2. The tone reproduction means comprises one additional dot as a single region of the device recognition pattern to be added, which is made up of a plurality of pixels, and the device recognition pattern to be added due to a difference in dot growth in the plurality of pixels. The image processing device according to claim 1, wherein