JP2000050069A - Picture binarization method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of composite black in a low gray level area, to improve the picture quality and to speed up the processing by holding the binarized result of a first color component as information in a noticed picture element and setting the output level of a second color component to be zero when the binarized result of the first color component is 'on'. SOLUTION: A judgment operation of first color component data of a noticed picture element by a first color component ON/OFF judgement part 103 is omitted. An error weighting computing unit 104 weights error data. The weighted data are binarized based on a binary threshold by a binarization processing part 105. The binarized result of the first color component is stored in a first color component ON/OFF data storage part 108. The first color component ON/OFF judgment part 103 refers to the first color component ON/OFF data in the noticed picture element and when the first color component is 'ON', the output level of second color component data is set to be zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an output device such as a printer, a scanner, a copying machine, a facsimile and the like, and is used to generate a binary image from multi-tone image data having a plurality of color components. The present invention relates to a method and an image binarization device.

[0002]

2. Description of the Related Art Conventionally, a multi-valued image (multi-tone image) has been
One of the methods for converting into a value image is an error diffusion method.

FIG. 4 is a block diagram showing a conventional image binarizing device. In FIG. 4, 1 is an image memory, 2 is a γ correction ROM, 3 is an adder, 4 is an error memory, 5 is a comparator,
6 is a weighted error calculator, 7 is a subtractor, and 8 is an error diffusion device.

Next, a binarization process by the conventional error diffusion method will be described with reference to FIG. In FIG. 4, multi-value data D of a pixel of interest to be subjected to a binarization process is read from the image memory 1, and the correction data stored in the γ correction ROM 2 is referred to in accordance with the printing characteristics of an output device such as a printer. Γ correction is performed to multi-value data. The adder 3 of the error diffusion device 8 adds the error data E at the pixel of interest to the multivalued data D 'corrected for γ, and outputs F = D' + E.

Next, in the comparator 5, the data F of the pixel of interest to which the error data E has been added is converted to a binary threshold value Th.
The binary signal B = "1" is output when F≥Th, and the binary signal B = "0" is output when F <Th. Such processing is called pseudo halftone processing. From this output result, the binarization error E in the binarization process is E = F−
It is calculated as B '. Here, B 'indicates that the input data is 2
In the case of 56 gradations (0 to 255), B ′ = B × 255
Becomes Therefore, for example, if the input multi-valued data is D =
D '= F = 230 When the binarization threshold value is Th = 128, the output data after binarization is B = “1”, and the binarization error E is E = FB−255. = 230-1 x 255 = -25. The binarization error E is stored in the error memory 4 in the weighting error calculator 6 for distribution to pixel data to be processed thereafter by a predetermined error matrix Mxy. The data is added to the data by the adder 3, whereby the error data is propagated. That is, in the example, while the input multi-valued data is D = 230, as a result of comparison with the binarization threshold value Th = 128, the output data after binarization is “1”, and there are 256 gradations. , 255 errors occur with respect to the input data D = 230. Therefore, input data D = 2
The error 25 with respect to 30 is defined as a binarization error, and the binarization error is distributed to the error memory 4 of the unprocessed pixel by the weighting error calculator 6 using the error matrix, and the binarization error in the subsequent pixels is calculated. Reflect on the value processing.

FIG. 5 is a data diagram showing an example of the error matrix Mxy. In FIG. 5, the pixel indicated by * is the current pixel of interest, and binarization processing is performed on this pixel.
The error generated when the target pixel is binarized is distributed to the unprocessed next pixel by the weighting coefficients (7, 1, 5, 3) shown in FIG. Then, when performing the binarization processing of the pixel of interest indicated by *, the error distribution value stored in the error memory 4 is read out, and the image memory 1 is used by using this error distribution value.
Is corrected for the next input data D 'read out from.

As described above, in the error diffusion method, a binarization error generated in a binarization process of a certain pixel is distributed to pixel data to be binarized thereafter, and after binarization, the image data and the original data are returned. Is a method of minimizing the error with respect to the multi-valued image data.

[0008]

However, in the conventional image binarization method, there is a problem that composite black occurs when the image is in a low density area in an image subjected to the binarization processing by the error diffusion method. Had. This means that a certain pixel has a first color component, a second color component,
The third color component (for example, cyan, magenta, and yellow) is simultaneously printed to generate black. When composite black occurs in a low-density region, the granularity becomes very high, and the processed image is processed. It causes deterioration. In addition, the error diffusion processing includes a matrix operation or the like for the error diffusion processing for each pixel and each color, and the processing load is extremely large.

In the image binarization method and the image binarization device, it is required to suppress the occurrence of composite black in a low density area.

The present invention provides an image binarization method for suppressing the generation of composite black in a low density region and realizing an improvement in image quality and speeding up the processing, and a method for generating a composite black in a low density region. It is an object of the present invention to provide an image binarizing device capable of suppressing the image quality and improving the processing speed.

[0011]

In order to achieve the object, an image binarization method according to the present invention is to input multi-gradation image data having a plurality of color components, and to perform the pseudo-halftone processing.
An image binarization method for generating a value image, wherein a binarization result of a first color component is held as information at a pixel of interest,
When the binarization result of the first color component is on in the target pixel, the output level of the second color component is set to zero.

As a result, an image binarization method for suppressing the generation of composite black in a low density area and improving image quality and realizing high-speed processing can be obtained.

An image binarizing apparatus according to the present invention for achieving the above object receives multi-tone image data having a plurality of color components and generates a binary image by pseudo halftone processing. A first color component ON for holding, as information, a binarization result of a first color component in a pixel of interest
/ OFF data storage unit and a first color component ON / OFF determination unit that sets the output level of the second color component to zero when the binarization result of the first color component is on in the pixel of interest. Is provided.

As a result, it is possible to obtain an image binarizing apparatus capable of suppressing the occurrence of composite black in a low density area and improving the image quality and realizing high-speed processing.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Image 2 according to claim 1 of the present invention
The binarization method is an image binarization method in which multi-tone image data having a plurality of color components is input and a binary image is generated by pseudo halftone processing. The binarization result is stored as information, and the first
When the binarization result of the color component is ON, the output level of the second color component is set to zero, and the overlap between the dots of the first color component and the dots of the second color component is determined. This has the effect of preventing the occurrence of composite black in the low density region.

According to a second aspect of the present invention, there is provided a method for binarizing an image, comprising inputting multi-gradation image data having a plurality of color components;
An image binarization method for generating a binary image by pseudo halftone processing, wherein a binarization result of a first color component and a second color component is held as information in a target pixel, and a first binarization method is performed in the target pixel. If the binarization result of the color component is on, the second
And the output level of the third color component is set to zero when any of the binarization results of the first color component and the second color component is on in the target pixel. The first color component, the second color component, and the third color component are prevented from overlapping with each other, and the occurrence of composite black in a low density region is suppressed. Having.

According to a third aspect of the present invention, there is provided an image binarizing apparatus which receives multi-gradation image data having a plurality of color components,
An image binarization device that generates a binary image by pseudo halftone processing, comprising: a first color component ON / OFF data storage unit that stores, as information, a binarization result of a first color component in a pixel of interest; A first color component ON / OFF determination unit that sets the output level of the second color component to zero when the binarization result of the first color component is on in the target pixel. This has the effect of preventing the dots of the first color component and the second color component from overlapping and suppressing the occurrence of composite black in the low density region.

According to a fourth aspect of the present invention, there is provided an image binarizing apparatus which inputs multi-gradation image data having a plurality of color components,
An image binarization device that generates a binary image by pseudo halftone processing, comprising: a first color component ON / OFF data storage unit that stores, as information, a binarization result of a first color component in a pixel of interest; A second color component ON / OFF data storage unit that holds the binarization result of the second color component as information in the target pixel, and a case where the binarization result of the first color component is on in the target pixel Is a first color component ON / OFF with the output levels of the second color component and the third color component being zero.
A determination unit; and a second color component ON / OFF determination unit that sets the output level of the third color component to zero when the binarization result of the second color component is on in the target pixel. The first color component, the second color component, and the third color component have an effect of preventing dots from overlapping each other and suppressing the occurrence of composite black in a low density region. .

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a block diagram showing an image binarizing apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 100 denotes an image memory for storing image data to be binarized; 101, an image memory 10;
After converting the image data stored in 0 into CMYK, a gamma correction ROM storing a conversion table for correcting the gamma characteristic according to the characteristics of the output device, 102 is an error diffusion device, 103 is a first color component ON / OFF determination unit, 104
Is an error weighting calculator, 105 is a binarization processing unit, 106
Denotes an error calculation unit, 107 denotes an error data storage unit, and 108 denotes a first color component ON / OFF data storage unit.

The general operation and function of the image binarizing apparatus thus configured will be described.

In FIG. 1, an error diffusion device 102 includes a first color component ON / OFF determination unit 103, an error weighting calculator 104, a binarization processing unit 105, an error calculation unit 106,
An error data storage unit 107 and a first color component ON / OFF data storage unit 108 are provided, and a first color component ON / OFF determination unit 103 is provided with a first color component ON / OFF.
Referring to the data stored in the data storage unit 108, it is determined whether or not the first color component is ON at the target pixel in the binarization processing (whether or not the first color component exists). Make a decision. The error weighting calculator 104 stores the binarization error generated in the surrounding binarized pixels in the error data storage unit 1.
07, the image data of the target pixel is subjected to error weighting processing. The binarization processing unit 105 performs a binarization process on the weighted data output from the error weighting calculator 104 with reference to a binarization threshold. The binarized data is output as a binary signal. The first color component ON / OFF data storage unit 108 stores ON / OFF information of the binarized data of the first color component, and the first color component ON / OFF determination unit 103 stores this information. Referenced. The error calculation unit 106 includes the binarization processing unit 10
5, an error of the image data generated when the binarization is performed is calculated, and the calculated error data is stored in the error data storage unit 107.
And is referred to when the error weighting operation unit 104 weights the error.

Next, the operation of the image binarizing apparatus shown in FIG. 1 will be described in detail. In the present embodiment, a description will be given of an operation for eliminating dots of the first color component and the second color component when binarizing the data converted from RGB to CMYK by the error diffusion method.

The image data stored in the image memory 100 is converted into CMYK data, corrected by a correction table in the gamma correction ROM 101, and then corrected by the error diffusion device 10.
Transferred to 2. In the error diffusion device 102, the first
Are binarized by error diffusion processing in order from the color component of. First, the binarization processing for the first color component will be described. At the time of the first color component processing, the determination operation by the first color component ON / OFF determination unit 103 is omitted, and the error weighting calculator 104 refers to the error data at the surrounding pixels stored in the error data storage unit 107. Then, the weighting of the error data is performed on the first color component data of the target pixel. The weighted data is binarized by the binarization processing unit 105 based on the binarization threshold. The binarization error generated at the time of binarization is calculated by the error calculation unit 106, and the calculated error data is stored in the error data storage unit 107.

Here, the binarization result of the first color component is turned on.
It is stored in the first color component ON / OFF data storage unit 108 as / OFF data. That is, when the first color component exists and the binary data (binary signal value) is “1”, it is ON.
Stores data (ON data), OFF when it is "0"
Stores data (off data).

After the binarization of the first color component is completed, binarization processing of the second color component is performed. The image data of the second color component is stored in the CMYK image memory 100 in the same manner as the first color component.
After conversion and γ correction processing in the γ correction ROM 101, the data is transferred to the error diffusion device 102. In the error diffusion device 102,
First, the first color component ON / OFF determination unit 103 refers to the first color component ON / OFF data at the pixel of interest stored in the first color component ON / OFF data storage unit 108, and performs the first If the color component is ON, the output of the second color component is turned OFF (the output level of the second color component is set to zero), and an OFF signal is output without performing the error diffusion process. If the first color component is OFF, normal error diffusion processing is performed, the error data in the error data storage unit 107 is weighted by the error weighting calculator 104, and binarization is performed by the binarization processing unit 105. And outputs the result as a binary signal. For the third color component, the error diffusion device 10
2 for normal error diffusion processing and ON of the first color component
The binary signal is output without referring to the / OFF data.

As described above, according to the present embodiment, the first color component ON / OFF data storage unit 108 that holds, as information, the binarization result of the first color component at the target pixel.
And a first color component ON / OFF determination unit 103 that sets the output level of the second color component to zero when the binarization result of the first color component is on in the target pixel. As a result, overlapping of the dots of the first color component and the second color component can be prevented, so that the occurrence of composite black in a low density region can be suppressed, and image quality can be improved.
Higher processing speed can be realized.

(Embodiment 2) FIG. 2 is a block diagram showing an image binarizing apparatus according to Embodiment 2 of the present invention.

In FIG. 2, an image memory 100, a gamma correction ROM 101, an error diffusion device 102, and a first color component ON.
/ OFF determination unit 103, error weighting calculators 104,
Value processing section 105, error calculation section 106, error data storage section 107, first color component ON / OFF data storage section 10
8 is the same as that in FIG. 1, the same reference numerals are given, and the description is omitted. Reference numeral 109 denotes a second color component ON / OFF data storage unit, and reference numeral 110 denotes a second color component ON / OFF determination unit. As described above, the image binarization apparatus of FIG. 2 is different from the apparatus of FIG. 1 in that the second color component ON / OFF data storage unit 10
9 and a second color component ON / OFF determination unit 110 are added.

The detailed operation of the image binarizing apparatus thus configured will be described. In the present embodiment, overlapping of the dots of the first color component, the second color component, and the third color component is prevented.

In FIG. 2, the image data stored in the image memory 100 is converted into CMYK data, and γ
After being corrected by the correction table in the correction ROM 101, it is transferred to the error diffusion device 102. Error diffusion device 1
In 02, binarization is performed by error diffusion processing in order from the first color component.

First, the binarization process for the first color component will be described. First color component ON / O during first color component processing
FF determination unit 103 and second color component ON / OFF determination unit 1
The determination operation at 10 is omitted, and the error weighting arithmetic unit 1
In step 04, the first color component data of the target pixel is weighted with the error data by referring to the error data of the surrounding pixels stored in the error data storage unit 107. The weighted data is binarized by the binarization processing unit 105 based on the binarization threshold. The binarization error generated at the time of binarization is calculated by the error calculation unit 106, and the calculated error data is stored in the error data storage unit 107.

Here, the binarization result of the first color component is turned on.
It is stored in the first color component ON / OFF data storage unit 108 as / OFF data.

After the first color component binarization is completed, a second color component binarization process is performed. Similarly to the first color component, the image data of the second color component is subjected to CMYK data conversion of the image data stored in the image memory 100 and the γ correction processing by the correction table in the γ correction ROM 101, and then the error diffusion device 1
02. In the error diffusion device 102, first,
In the first color component ON / OFF determination unit 103, the first
With reference to the first color component ON / OFF data at the pixel of interest stored in the color component ON / OFF data storage unit 108, if the first color component is ON, the output of the second color component is output. As OFF, an OFF signal is output without performing error diffusion processing, and OFF information is stored in the second color component ON / OFF data storage unit 109. If the first color component is OFF, normal error diffusion processing is performed, the error data in the error data storage unit 107 is weighted by the error weighting calculator 104, and binarization is performed by the binarization processing unit 105. Do
The result is output as a binary signal, and the binary result is stored in the second color component ON / OFF data storage unit 109.

Next, the processing of the third color component will be described. The image data of the third color component is transferred from the image memory 100 to the error diffusion device 102 after the γ correction in the γ correction ROM 101. In the error diffusion apparatus 102, first, the first color component ON / OFF data at the target pixel stored in the first color component ON / OFF data storage unit 108 in the first color component ON / OFF determination unit 103 is obtained. Then, the second color component ON / OFF determination unit 110 refers to the second color component ON / OFF data at the pixel of interest stored in the second color component ON / OFF data storage unit 109, and When either the first color component or the second color component is ON, the output of the third color component is turned OFF, and an OFF signal is output without performing error diffusion processing. If both the first color component and the second color component are OFF, normal error diffusion processing is performed, and the error data in the error data storage unit 107 is weighted by the error weighting arithmetic unit 104 to perform binarization processing. The binarization is performed by the unit 105, and the result is output as a binary signal. That is, the first color component ON / O
When the binarization result of the first color component is on in the target pixel, the FF determination unit 103 sets the output levels of the second color component and the third color component to zero, and sets the second color component ON
The / OFF determination unit 110 sets the output level of the third color component to zero when the binarization result of the second color component is on in the target pixel.

Next, the operation of the image binarizing apparatus shown in FIG. 2 will be described with reference to FIG. FIG. 3 is a flowchart for explaining the operation of the image binarization device of FIG.

In FIG. 3, first, the image data of the target pixel is subjected to color conversion from RGB data to CMYK data (S1), and respective data of CMYK are calculated. Next, gamma correction (γ correction) is performed to correct the CMYK data generated in step 1 into data corresponding to the color reproduction characteristics of the output device (S2). γ correction is γ correction R
This is performed by the OM101. Binarization is performed on the corrected data in the order of CMYK. Processing of each of CMYK will be described below.

First, the processing of the first color component will be described. When the first color component ON / OFF determination unit 103 determines that the first color component is present (S3), the weighting of the error data in the pixels surrounding the pixel of interest is performed by the error weighting calculator 10
In step 4, the binarization processing unit 105 performs a binarization process by comparing with a binarization threshold (S4). Next, it is determined whether the binarization result (CDot) is ON or OFF (S5). If the result is ON, the first color component ON / OFF data D
ATA1 is set to ON, and the first color component ON / OF
The data is stored in the F data storage unit (S6). Also the result is OFF
If so, DATA1 is set to OFF and stored (S7). Next, the error calculator 106 calculates an error generated during the binarization (S18), stores the error data in the error data storage 107 (S19), and turns on / off the first color component.
The F determination unit 103 determines whether all pixels have been completed (S2).
0), if it is determined that the processing has not been completed, the process returns to step 1.

Next, the second color component will be described. When the second color component ON / OFF determination unit 110 determines that the first color component does not exist and the second color component exists (S8), the first color component that has been subjected to the binarization processing is determined. Binarization result is second
Is referred to from the color component ON / OFF data storage unit 109 (S9). If DATA1 is ON, the second color component O
By setting N / OFF data DATA2 to OFF,
The data is stored in the second color component ON / OFF data storage unit 109 (S13), and the binary data is output as OFF. If DATA1 is OFF (S9), the error data is weighted, compared with a binarization threshold, and binarized (S10). Next, the result of binarization (DATA
2) ON or OFF is determined (S11), and the result is O
If N, the second color component ON / OFF data DATA
2 is set to ON and stored (S12). If the result is OFF, DATA2 is set to OFF and stored (S13). Next, a binarization error is calculated (S1
8) The calculated error data is stored (S19), and it is determined whether or not all pixels have been completed (S20). If it is determined that all the pixels have not been completed, the process returns to step 1.

Next, the third color component will be described. When the second color component ON / OFF determination unit 110 determines that the first and second color components are not present and the third color component is present (S1
4), the binarization results of the first and second color components that have already been binarized are converted into ON / OFF data DATA1, D
Referring to ATA2 (S15), if either is ON, the binarization result is output as the third color component OFF (S16). In addition, both the first color component and the second color component are O
If it is FF (S15), the error data is weighted, compared with the binarization threshold, and binarized (S15).
17). Next, a binarization error is calculated (S18), the calculated error data is stored (S19), and the second color component is turned on.
The / OFF determination unit 110 determines whether or not all pixels have been completed (S20). If it is determined that all pixels have not been completed, the process returns to step 1.

As described above, according to the present embodiment, the first color component ON / OFF data storage unit 108 that holds, as information, the binarization result of the first color component at the target pixel.
A second color component ON / OFF data storage unit 109 that holds the binarization result of the second color component as information in the target pixel, and that the binarization result of the first color component is on in the target pixel. In some cases, the first color component ON / OFF determination unit 103 that sets the output levels of the second color component and the third color component to zero, and the binarization result of the second color component at the target pixel is turned on. , The second color component ON / OFF determination unit 110 that sets the output level of the third color component to zero is provided, so that the first color component, the second color component, and the third Since the overlapping of the dots of the color component can be prevented, it is possible to suppress the occurrence of composite black in a low density area, and to improve the image quality and speed up the processing.

[0042]

As described above, according to the image binarization method according to the first aspect of the present invention, multi-tone image data having a plurality of color components is input, and the binary image data is subjected to pseudo-halftone processing. An image binarization method for generating an image, wherein a binarization result of a first color component is held as information at a target pixel, and a binarization result of a first color component is on at the target pixel. By setting the output level of the second color component to zero,
Since it is possible to prevent dots of the first color component and the second color component from overlapping with each other, it is possible to suppress the occurrence of composite black in a low-density area, and to improve image quality and speed up processing. This has the advantageous effect of being able to perform.

According to the image binarization method of the second aspect of the present invention, an image binarization method in which multi-tone image data having a plurality of color components is input and a binary image is generated by pseudo halftone processing
A binarization method in which a binarization result of a first color component and a second color component is held as information in a target pixel, and the binarization result of the first color component is on in the target pixel. The output level of the second color component is set to zero, and the output of the third color component is performed when any of the binarization results of the first color component and the second color component is on in the target pixel. By setting the level to zero, it is possible to prevent the first color component, the second color component, and the third color component from overlapping with each other, thereby suppressing the occurrence of composite black in a low density area. This has the advantageous effect of improving image quality and speeding up processing.

According to the image binarizing device of the third aspect of the present invention, an image binarizing apparatus which receives multi-tone image data having a plurality of color components and generates a binary image by pseudo halftone processing
A binarization device, wherein a pixel of interest has a first color component of 2
First color component ON / OF holding the binarization result as information
F data storage unit and the first color component 2
By providing a first color component ON / OFF determination unit for setting the output level of the second color component to zero when the binarization result is on, the first color component and the second color component are determined. Since overlapping of dots can be prevented, it is possible to suppress the occurrence of composite black in a low-density region, and to obtain an advantageous effect that image quality can be improved and processing can be speeded up.

According to the image binarizing apparatus of the present invention, multi-tone image data having a plurality of color components is input, and the image binarizing apparatus generates a binary image by pseudo halftone processing.
A binarization device, wherein a pixel of interest has a first color component of 2
First color component ON / OF holding the binarization result as information
F data storage unit and the second color component 2
Second color component ON / OF that holds the binarization result as information
F data storage unit and the first color component 2
If the binarization result is on, the second color component and the third color component
The first color component ON /
An OFF determination unit; and a second color component ON / OFF determination unit that sets the output level of the third color component to zero when the binarization result of the second color component is on in the pixel of interest. Thus, the first color component, the second color component, and the third
Color components can be prevented from overlapping with each other, thereby suppressing the occurrence of composite black in low-density areas, and has the advantageous effect of improving image quality and speeding up processing. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an image binarization device according to a first embodiment of the present invention;

FIG. 2 is a block diagram illustrating an image binarization device according to a second embodiment of the present invention;

FIG. 3 is a flowchart showing the operation of the image binarization device of FIG. 2;

FIG. 4 is a block diagram showing a conventional image binarization device.

FIG. 5 is a data diagram showing an example of an error matrix.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Image memory 101 γ correction ROM 102 Error diffusion device 103 First color component ON / OFF determination unit 104 Error weighting calculator 105 Binarization processing unit 106 Error calculation unit 107 Error data storage unit 108 First color component ON / OFF OFF data storage unit 109 Second color component ON / OFF data storage unit 110 Second color component ON / OFF determination unit

Claims (4)

[Claims] An image binarization method for inputting multi-tone image data having a plurality of color components and generating a binary image by pseudo halftone processing, wherein a first color component of a pixel of interest is Image 2 wherein the binarization result is held as information, and when the binarization result of the first color component is on at the pixel of interest, the output level of the second color component is set to zero. Value method. 2. An image binarization method for inputting multi-gradation image data having a plurality of color components and generating a binary image by pseudo halftone processing, wherein a first color component and The binarization result of the second color component is held as information, and when the binarization result of the first color component is on at the target pixel, the output level of the second color component is set to zero, Image binarization wherein the output level of the third color component is set to zero when one of the binarization results of the first color component and the second color component is on in the target pixel. Method. 3. An image binarization device for inputting multi-gradation image data having a plurality of color components and generating a binary image by pseudo halftone processing, wherein a target pixel has a first color component First color component ON / O holding the binarization result as information
An FF data storage unit, and a first color component ON / OFF determination unit that sets the output level of the second color component to zero when the binarization result of the first color component is on in the pixel of interest. An image binarization device comprising: 4. An image binarization apparatus for receiving multi-tone image data having a plurality of color components and generating a binary image by pseudo halftone processing, wherein a first color component of a pixel of interest is First color component ON / O holding the binarization result as information
An FF data storage unit, and a second color component ON for holding, as information, a binarization result of a second color component in the target pixel
/ OFF data storage unit and a first unit that sets the output levels of the second color component and the third color component to zero when the binarization result of the first color component is on in the pixel of interest.
And a second color component ON for setting the output level of the third color component to zero when the binarization result of the second color component is on in the target pixel.
An image binarization device, comprising: a / OFF determination unit.