JPH06253161A - Picture processor - Google Patents

Abstract

PURPOSE:To provide a picture processor in which a black character or the like is easily read by expressing a chromatic part and an achromatic part such as a black character in two coloring materials with respect to a picture in which the achromatic part such as a boundary character is in existing in the chromatic color and making a border between the chromatic color and the black character or the like clear. CONSTITUTION:R, G, B signals subjected to smoothing processing are inputted to a recognition discrimination circuit 10, in which to which hue of recognized colors registered in advance a noticed picture element belongs is discriminated and the result is outputted to a pattern generator 27. Moreover, the result is inputted to an achromatic color discrimination circuit 8 whether the surrounding of the noticed picture element is at a white level or a black level is discriminated by a block level discrimination signal and a white level discrimination signal based on an achromatic color discrimination signal and at which position of the boundary between the chromatic color and the achromatic color the noticed picture element resides is discriminated. Then a density signal from a 4th LUT 33 is selected based on an output signal of the achromatic color discrimination circuit 8 and an AND circuit 22 and a black picture is displayed and the boundary the chromatic color and the black part is displayed in a black thick line.

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 reading a color image and converting the image into an image which can be expressed by two coloring materials.

[0002]

2. Description of the Related Art A system in which a so-called reader for reading a color image and a monochrome printer are combined has been proposed. Then, of the input images, a monochrome image is expressed as a gradation image, and a color-coded meaningful image such as a color graph is displayed.
For example, an image processing apparatus has been proposed in which an image as shown in FIG. 6A is represented by performing pattern division processing for each hue by combining oblique lines and dotted lines as shown in FIG. 6B.

FIG. 5 is a block diagram showing a control circuit of a conventional image processing apparatus.

R, G, which are conventionally read by a reader or the like,
R (red), G (green), and B that have been separated into the three primary colors of light with B
The (blue) signals are respectively the first, second and third smoothing processing circuits (smoothing circuits) 101, 102 and 103.
To the achromatic color determination circuit 107 and the hue determination lookup table (LUT) 108 after the visual characteristics are corrected by the first, second and third lookup tables (LUT) 104, 105 and 106. It The achromatic color determination circuit 107 calculates the difference between the maximum value and the minimum value of the R, G, B signals, and if the value is less than or equal to a predetermined threshold value, "1", and if the value is greater than or equal to the predetermined threshold value, the achromatic color determination is "0". A signal is output, and the achromatic color determination signal is output to the selector 112.
Entered in. Also, the hue determination lookup table 10
8 outputs a hue angle tan (b / a) signal on the ab plane in the Lab coordinate space from the R, G, B signals, and this tan (b
The / a) signal is input to the pattern generator 110 via the certified color discrimination circuit 109. Based on the hue angle tan (b / a) signal, the authorized color determination circuit 109 determines which registered color the hue belongs to. The pattern generator 110 generates a pattern signal corresponding to the hue discriminated by the certified color discrimination circuit 109, that is, a signal which expresses by patterning each color by combining oblique lines and dotted lines, and the pattern signal is sent to the selector 112. Is entered. On the other hand, the G signal is the fourth lookup table (LU
T) 111 is input and converted into a density signal, and then input to the selector 112. The selector 112 selects and outputs a density signal when the achromatic signal is "1" and a pattern signal when the achromatic signal is "0".

[0005]

However, in the above-mentioned conventional image processing apparatus, if the area of the smoothing processing is widened, black characters in chromatic colors are not judged as achromatic and black characters are not processed as characters. On the contrary, if the smoothing area is narrowed, there is a problem that rough color halftone dots cannot be converted into a uniform pattern image. Further, for example, a black character in a chromatic color as shown in FIG. 7 (a) is arranged in a pattern image as shown in FIG. 7 (b) even if it is determined to be an achromatic color, which makes it difficult to see. was there.

The present invention has been made in order to solve the above-mentioned conventional problems, and its object is to eliminate the chromatic color portion and the black character from an image having an achromatic color portion such as a black character in the chromatic color. It is an object of the present invention to provide an image processing device that can express a colored portion with two colors of coloring materials, make the boundary between a chromatic color and a black character clear, and perform image processing on the black character and the like in an easy-to-read manner.

[0007]

In order to achieve the above object, the present invention provides an image processing apparatus capable of outputting an image with coloring materials of at least two colors based on an input color separation signal. Smoothing processing means for performing a smoothing process, and first judging means for judging a chromatic color and an achromatic color based on the difference between the maximum value and the minimum value of the color separation signal smoothed by the smoothing processing means. Of the achromatic color determined by the first determination means, the achromatic color part excluding white is displayed by the first coloring material, and the chromatic color part is displayed by the second coloring material. And a hue angle processing means for performing a predetermined patterning process according to the hue angle of the chromatic color.

To achieve the same object, in addition to the constituent features of claim 1, the smoothing processing means changes the smoothing coefficient of the smoothing processing according to the color separation signal. Second determining means for determining whether the achromatic color determined to be achromatic by the first determining means is white or black, a boundary between the black portion and the chromatic color portion, and the white color. Recognition means for recognizing the boundary between the color part and the chromatic part,
Boundary coloring processing means for performing different coloring processing on the boundary between the black portion and the chromatic portion and the boundary between the white portion and the chromatic portion by using the first coloring material and the second coloring material. It is preferable.

[0009]

According to the image processing apparatus of the present invention, the chromatic color and the achromatic color are determined based on the difference between the maximum value and the minimum value of the color separation signal smoothed by the smoothing processing means by the first judging means. Of the determined achromatic color, the achromatic color part excluding white is displayed by the first coloring material, the chromatic color part is displayed by the second coloring material, and the chromatic color is processed by the hue angle processing means. A predetermined patterning process is performed according to the hue angle of the part.

According to the image processing apparatus of claim 2, in addition to the invention of claim 1, the smoothing processing means changes a smoothing coefficient in smoothing processing according to the color separation signal. It has a changing means. Then, the second determination means determines whether the achromatic color determined to be an achromatic color by the first determination means is white or black, and further, the recognition means determines a boundary between the black portion and the chromatic color portion. The boundary between the white part and the chromatic color part is recognized, and the boundary coloring processing means uses the first coloring material and the second coloring material to define the boundary between the black part and the chromatic color part, and the white part and the chromatic color part. Coloring is applied so that the boundary between and is different.

[0011]

Embodiments of the present invention will be described in detail below with reference to FIGS.

[First Embodiment] An image processing apparatus according to the present embodiment reads R, G and B signals which are three primary color signals,
1 is a device capable of processing and outputting an achromatic color part excluding a white part to a black (first) colorant, and a chromatic color part to an image that can be expressed by a red (second) colorant. FIG. 3 is a block circuit diagram showing a control circuit configuration of the device.

In the figure, reference numeral 1 is a luminance discriminating circuit for discriminating luminance, and reference numerals 2, 3 and 4 are first, second, and
Third smoothing circuits 5, 6, and 7 are first, second, and third correction circuits that correct the R, G, and B luminance signals smoothed by the first to third smoothing circuits 2 to 4 so as to match visual characteristics.
Third lookup table (LUT), 8 is R, G, B
An achromatic color determination circuit for determining an achromatic color from the difference between the maximum value and the minimum value of the signal, 9 is a hue determination lookup table (LUT) for determining an angle on the ab plane in the Lab coordinate space, 1
0 is a certified color discrimination circuit for discriminating which color is registered in advance, 11 and 12 are first and second comparators 13, 14 and 21, 22, 23, respectively.
Is an AND circuit, 15, 16 and 17 are a first 9 × 9 OR circuit that takes a logical sum within each region, and a first 3 × 3 OR circuit
Circuit and second 3 × 3 OR circuit, 18, 19 and 25 are XOR circuits, 20 and 35 are NOT circuits, 24 is an OR circuit, 26 is a NAND circuit, 27 is a color discriminated by the certified color discrimination circuit 10. In the present embodiment, a pattern generator that generates a predetermined pattern signal colored with a red coloring material, 28 is a red solid pattern (red edge) signal, and 29 is a white pattern. Pattern generators that generate (white) signals respectively, 3
Reference numerals 0, 31, 32, 36 and 37 denote multipliers, and 33 denotes a fourth look-up table (LU for converting a luminance signal into a density signal).
T) and 34 are adders.

Next, a description will be given of the principle of operation of the present apparatus having the above-described configuration, which performs different coloring processing on the boundary between the black portion and the chromatic color portion and the boundary between the white portion and the chromatic color portion by using the coloring materials of two colors.

The input R, G and B signals are input to the luminance discriminating circuit 1, respectively. The luminance discriminating circuit 1 calculates the minimum value of the R, G, B signals and the difference between the maximum and minimum values of the R, G, B signals, and outputs a discrimination signal for discriminating the luminance. The R, G, B signals are first to
It is also input to the third smoothing circuits 2 to 4, respectively.
Then, in the first to third smoothing circuits 2 to 4, in the smoothing process based on the determination signal, the smoothing coefficient is changed, and when the circuit 1 determines that the brightness is dark,
For example, if it is determined that the image is not dark without performing the smoothing process, for example, the smoothing process with 5 × 5 pixels is performed. First
-Third lookup tables (LUT) 5-7 correct the smoothed R, G, B luminance signals so as to match the visual characteristics. The corrected R, G, B signals (hereinafter, referred to as “corrected RGB signals”) are achromatic color determination circuit 8.
And the hue determination LUT 9 are input. The achromatic color determination circuit 8 calculates the difference between the maximum value and the minimum value of the corrected RGB signal, and when the difference value is less than or equal to a predetermined threshold value, the achromatic color signal of “1” is output. Output.

On the other hand, the hue determination LUT 9 outputs a hue angle tan (b / a) signal for the corrected RGB signal. The authorized color determination circuit 10 determines which of the registered authorized colors is registered in advance based on the hue angle tan (b / a) signal. Further, the G signal is the second smoothing circuit 3 and the second LU.
A first comparator 11 and a second comparator 1 via T6, respectively.
Entered in 2. The first comparator 11 outputs a bright part determination signal of "1" when the G signal is equal to or more than a predetermined threshold value and "0" when the G signal is less than or equal to the predetermined threshold value. Is “1”, and is “0” when the threshold value is exceeded.
Is output. The AND circuit 13 takes the logical product of the bright part determination signal and the achromatic color determination signal,
Output the white judgment signal. Further, the AND circuit 14 calculates the logical product of the dark area determination signal and the achromatic color determination signal, and outputs a black determination signal. The black determination signal is input to the first 9 × 9 OR circuit 15 and the first 3 × 3 OR circuit 16, and the white determination signal is input to the second 3 × 3 OR circuit 17.

The first 9 × 9 OR circuit 15 outputs the black decision signal of all 9 × 9 = 81 pixels around the pixel of interest (hereinafter referred to as “pixel of interest”) for the pixel currently being processed. If there is a pixel for which the black determination signal is "1" even if one of them is ORed, the output signal of the first 9 × 9 OR circuit 15 becomes "1", and the black determination signals of all the pixels are "1". When it is “0”, the output signal of the first 9 × 9 OR circuit 15 is “0”. Similarly, the first 3 × 3 OR circuit 16
Is ORed with the black determination signals of all 3 × 3 = 9 pixels around the pixel of interest.

The XOR circuit 18 has a first 9 × 9O
The exclusive OR of the output signal of the R circuit 15 and the output signal of the first 3 × 3 OR circuit 16 is calculated. The output signal of the XOR circuit 18 becomes “1” when there is no pixel determined to be black in the 3 × 3 pixel area around the target pixel and there is a pixel determined to be black in the 9 × 9 pixel area. That is, the output signal is "1" when the target pixel is separated from the pixel determined to be black by four pixels. In addition, the first 3 × 3 OR circuit 16
Is 1 from the pixel in which the pixel of interest is determined to be chromatic and black.
When the pixels are separated from each other, that is, when the pixel is adjacent to the pixel determined to be black, the output signal becomes "1".

Further, the AND circuit 21 inputs the inverted signal of the achromatic color determination signal input via the NOT circuit 20 and the XO signal.
The logical product with the output signal of the R circuit 18 is calculated. That is, the output signal of the AND circuit 21 becomes "1" when the pixel of interest is chromatic and is separated from the pixel determined to be black by four pixels. Similarly, the output signal of the AND circuit 22 becomes "1" when the pixel of interest is one pixel away from the pixel which is determined to be chromatic and black.

The output signals (boundary determination signals) from the AND circuits 21 and 22 are XOR circuits 25 and O.
It is input to each R circuit 24.

Further, the second 3 × 3 OR circuit 17 takes a logical sum of the target pixel and the white determination signals of all 3 × 3 = 9 pixels around the target pixel, and even one of them determines the white. If there is a pixel whose signal is “1”, the output signal of the second 3 × 3 OR circuit 17 becomes “1”, and when the white determination signals of all the pixels are “0”, the second 3 × 3 OR circuit The output signal of 17 becomes "0". In addition, the XOR circuit 1
The output signal 9 is "1" when the pixel of interest is one pixel away from the pixel determined to be white, that is, when it is adjacent to the pixel determined to be black. Further, the AND circuit 23 is
The logical product of the inverted signal of the achromatic color determination signal input via the OT circuit 20 and the output signal of the XOR circuit 19 is calculated. That is, the output signal of the AND circuit 23 becomes "1" when the pixel of interest is one pixel away from the pixel which is determined to be chromatic and white. The output signal (boundary determination signal) from the AND circuit 23 is input to the multiplier 31.

Then, the multiplier 31 outputs a signal obtained by multiplying the output signal from the AND circuit 23 and the red solid pattern signal from the red solid pattern generator 28 to the adder 34.

The XOR circuit 25 also includes an AND circuit 21.
Of the output signal of the AND circuit 23 and the output signal of the AND circuit 23 are exclusive-ORed, and the signal (exclusive-OR signal) is multiplied by the multiplier 32.
Output to. The multiplier 32 outputs a signal obtained by multiplying the exclusive OR signal and the white pattern signal from the white pattern signal generator 29 to the adder 34.

Further, the NAND circuit 26 is the AND circuit 2
A negative logical product of the output signal of 1 and the output signal of the AND circuit 23 is calculated, and the output signal is output to the multiplier 30.
The multiplier 30 outputs a signal obtained by multiplying the output signal of the NAND circuit 26 and the pattern signal from the pattern generator 27 to the adder 34.

As described above, the OR circuits 15 to 17 perform a logical sum, and the XOR circuits 18 and 19 perform an exclusive logical sum based on the output signals, so that there is a white portion around the target pixel or a black portion. Determine if there is. And
The logical product of the inversion signal of the achromatic color determination signal and the input signal of the AND circuits 21 to 23 is used to determine at which position on the boundary between the chromatic color and the achromatic color the target pixel is located.

On the other hand, the G signal is converted into a density signal by the LUT 33. Further, the multiplier 36 selects the density signal when the achromatic color determination signal input via the OR circuit 24 is "1", and an image is displayed with a black (first) coloring material. The multiplier 36 outputs the density signal when the output signal of the AND circuit 22 input through the OR circuit 24 is “1”, that is, when there is a pixel adjacent to the chromatic color that is determined to be black. The border line between the chromatic color and the black portion is selected and displayed as an image with a thick line colored with a black coloring material.

On the other hand, the multiplier 37 adds the adder 34 when the achromatic color determination signal input through the OR circuit 24 is "0" and the signal is inverted by the NOT circuit 35 to be "1". Is selected, and in this embodiment, an image is displayed in a predetermined pattern, a red solid pattern, or a white pattern according to the hue colored with the red (second) coloring material.

Actually, in the case of the sample in which the black portion, the chromatic color portion and the white portion are color-coded as shown in FIG. 2A, the chromatic color portion is colored in red as shown in FIG. 2B. The black part is displayed by the black image and the white part is displayed by the white image by the image of the predetermined pattern colored with the coloring material, and the boundary between the chromatic color and the black is defined by the thick black line. Further, the border between the thick line and the chromatic color portion is displayed by a white image, and the border between the chromatic color and the white portion is displayed by a red solid pattern image.

Further, as shown in FIG. 3A, in the case of a sample in which 40%, 30%, and 25% black characters are displayed on the chromatic portions of red, yellow, and green, respectively,
As shown in FIG. 3B, an image is displayed in a predetermined pattern in which the chromatic color portion is colored with a red coloring material corresponding to each hue, and the background of the black character portion is hollowed out so that the black character is easy to see. Image is displayed.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a block circuit diagram showing the control circuit configuration of the image processing apparatus according to the second embodiment of the present invention.

In the figure, reference numeral 51 is a luminance discriminating device for discriminating luminance, and 52 to 54 are first to third portions for performing smoothing processing.
Smoothing circuits 55 to 57 are first to third look-up tables (LUTs) for correcting the R, G, and B signals smoothed by the first to third smoothing circuits 52 to 54 so as to match the visual characteristics. Reference numeral 58 is an achromatic color determination circuit that determines an achromatic color from the difference between the maximum value and the minimum value of the R, G, and B signals, and 59 is a hue determination lookup table (LUT) that determines an angle on the ab plane in the Lab coordinate space. Reference numeral 60 is a certified color discrimination circuit for discriminating which color is registered in advance, and 61 is a visually corrected LUT5.
First calculators for calculating visual brightness based on RGB signals of 5 to 57, 62 and 63 are first and second comparators, respectively.
Reference numerals 64, 65 and 79 to 84 are AND circuits, and 66 to 71 are logical sums in respective areas.
9 is the first and second 7 × 7 OR circuits, 67 and 70 are the first,
Second 5 × 5 OR circuit, 68 and 71 are first and second 3 ×
3OR circuits, 72 to 77 XOR circuits, 78 NOT circuits, 85 generates a pattern according to the color discriminated by the certified color discrimination circuit 60, and uses red (second coloring material),
A pattern generator that generates a predetermined pattern according to the determined hue, 86 is a fourth lookup table (LUT) that converts a luminance signal into a density signal, and 87 and 88 are ANDs.
The second and third calculators 89 to 91, which calculate the number of multiplications according to the degree of separation of the boundary between the chromatic color and the achromatic color, from the respective boundary position signals of the circuits 79 to 84, and the first to third calculators 89 to 91, respectively.
Multipliers 92 and 93 are first and second adders.

In the above structure, the input R, G and B signals are input to the luminance discriminating circuit 51. The brightness determination circuit 51 calculates the minimum value of the R, G, B signals and the difference between the maximum value and the minimum value of the R, G, B signals, and outputs a determination signal for determining the brightness of the brightness. The R, G, B signals are simultaneously input to the first to third smoothing circuits 52 to 54, respectively. First to third
The smoothing circuits 52 to 54 change the smoothing coefficient in the smoothing process according to the determination result of the brightness determining circuit 51, and perform the smoothing process on the R, G, and B signals, respectively. The discrimination signal output by the luminance discrimination circuit 51 is used only for changing the smoothing coefficient, and does not affect other processing.

The first to third LUTs 55 to 57 correct the smoothed R, G and B luminance signals so as to match the visual characteristics. The corrected R, G, B signals (hereinafter referred to as “corrected RGB signals”) are input to the achromatic color determination circuit 58 and the hue determination lookup table (LUT) 59.

The achromatic color determining circuit 58 calculates the difference between the maximum value and the minimum value of the corrected RGB signal in the pixel, and when the difference value is less than or equal to the predetermined threshold value, it is "1", and when it is more than the predetermined threshold value, it is "0". The achromatic color determination signal is output. That is, if the corrected R, G, B signals have almost the same level, it is judged as achromatic color, and if the corrected R, G, B signals have different levels, it is judged as chromatic color.

On the other hand, the hue determination LUT 59 is a correction RGB
A hue angle tan (b / a) signal on the ab plane in the Lab coordinate space corresponding to the signal is output by the signal. The authorized color determination circuit 60 determines the hue from the value of the hue angle tan (b / a) signal, and determines which of the authorized colors registered in advance belongs.

The first calculator 61 multiplies the corrected RGB signals at a ratio according to the spectral characteristics of the human eye to produce a luminance signal. This luminance signal is input to the first comparator 62 and the second comparator 63, respectively. The first comparator 62 outputs a bright part determination signal which is “1” when the luminance signal is equal to or higher than a predetermined threshold value and “0” when the luminance signal is equal to or lower than the predetermined threshold value. A dark area determination signal that is "1" when it is "0" when it is equal to or more than a predetermined threshold value is output. The AND circuit 64 takes the logical product of the bright area determination signal and the achromatic color determination signal output by the achromatic color determination circuit 58, and outputs a white determination signal. The AND circuit 65 takes the logical product of the dark area determination signal and the achromatic color determination signal and outputs a black determination signal.
This black determination signal is sent to the first 7 × 7 OR circuit 66, the first 5
The 5 × 5 OR circuit 67 and the first 3 × 3 OR circuit 68, and the white determination signal is the second 7 × 7 OR circuit 69 and the second 5 × 5 OR circuit.
It is input to each of the 5OR circuit 70 and the second 3 × 3 OR circuit.

The first 7 × 7 OR circuit 66 logically sums the target pixel with the black determination signals of all 7 × 7 = 49 pixels around the target pixel, and even one of them has the black determination signal “ If there are 1 "pixels, the first 7x7
The output of the OR circuit 66 becomes "1", and when the black determination signals of all the pixels are "0", the output of the first 7x7 OR circuit 66 becomes "0". Similarly, the first 5 × 5 OR circuit 67
Is the logical sum of the black determination signals of all 5 × 5 = 25 pixels around the pixel of interest, and the first 3 × 3 OR circuit 68
Is ORed with the black determination signal for all 3 × 3 = 9 pixels around the pixel of interest.

Then, the XOR circuit 72 uses the first 7 × 7
The exclusive OR of the output of the OR circuit 66 and the output of the first 5 × 5 OR circuit 67 is calculated. The XOR circuit 72 outputs “1” only when there is no pixel determined to be black in the 5 × 5 pixel area around the target pixel but there is a pixel determined to be black in the 7 × 7 pixel area. . That is, "1" is output when the pixel of interest is separated from the pixel determined to be black by three pixels. Similarly, the XOR circuit 73 outputs “1” when the pixel of interest is separated from the pixel determined to be black by two pixels.
Therefore, the XOR circuit 74 becomes "1" when the pixel of interest is one pixel away from the pixel determined to be black, that is, when the pixel of interest is adjacent to the pixel determined to be black.

The AND circuit 79 is the NOT circuit 78.
An inversion signal of the achromatic color determination signal input via
The logical product is taken with the output signal of the OR circuit 72. In other words, the AND circuit 79 outputs "1" when the pixel of interest is chromatic and 3 pixels away from the pixel determined to be black. Similarly, the AND circuit 80 outputs "1" when the pixel of interest is chromatic and is two pixels away from the pixel determined to be black.
The ND circuit 81 outputs "1" when the pixel of interest is chromatic and is one pixel away from the pixel determined to be black. The outputs (boundary determination signals) from the AND circuits 79 to 81 are input to the second calculator 87.

The second 7 × 7 OR circuit 69 takes the logical sum of the target pixel and the white determination signals of all 7 × 7 = 49 pixels around the target pixel, and even one of them outputs the white determination signal. If there is a pixel that is "1", the second 7
The output of the x7 OR circuit 69 becomes "1", and when the white determination signals of all the pixels are "0", the second 7x7 OR circuit 6
The output of 9 becomes "0". Similarly, the second 5 × 5 OR circuit 70 performs logical OR with the white determination signals of all 5 × 5 = 25 pixels around the pixel of interest, and the second 3 × 3 OR circuit 71 rotates around the pixel of interest. The logical sum of 3 × 3 = 9 pixels and all white determination signals is calculated.

The XOR circuit 75 takes the exclusive OR of the output of the second 7 × 7 OR circuit 69 and the output of the second 5 × 5 OR circuit 70. The XOR circuit 75 is arranged around the target pixel 5
Only when there is no pixel determined to be white in the × 5 pixel area, but there is a pixel determined to be white in the 7 × 7 pixel area,
Outputs "1". That is, it becomes "1" when the pixel of interest is separated from the pixel determined to be white by three pixels. Similarly, the XOR circuit 76 becomes "1" when the pixel of interest is separated from the pixel determined to be white by 2 pixels, and XO
The R circuit 77 becomes "1" when the pixel of interest is one pixel away from the pixel determined to be white, that is, when the pixel of interest is adjacent to the pixel determined to be white.

The AND circuit 82 is the NOT circuit 78.
XOR with the inverted signal of the achromatic color determination signal input via
It is ORed with the output signal of the circuit 75. That is, the AND circuit 82 outputs "1" when the pixel of interest is chromatic and three pixels away from the pixel determined to be white. Similarly, the AND circuit 83 outputs "1" when the pixel of interest is chromatic and is two pixels away from the pixel determined to be white.
The D circuit 84 outputs "1" when the pixel of interest is chromatic and is one pixel away from the pixel determined to be white. Outputs (boundary determination signals) from the AND circuits 82 to 84 are input to the third computing unit 88.

On the other hand, the pattern generator 85 generates a predetermined pattern according to the hue based on the signal sent from the certified color discrimination circuit 60. The luminance signal output from the first computing unit 61 is the fourth look-up table (LUT).
It is converted into a density signal by 86.

The third computing unit 88, when the inverted signal of the achromatic color determination signal is "0", that is, when the achromatic color determination circuit 58 determines that the pixel of interest is an achromatic color, the second multiplier 9
The output signal “0” is sent to 0 and the third multiplier 91. When the inverted signal of the achromatic color determination signal is "1", that is, when the pixel of interest is determined to be chromatic, AN
A signal corresponding to the boundary determination signal transmitted from the D circuits 82 to 84 is transmitted.

Specifically, the third computing unit 88, based on the inverted signal of the achromatic color determination signal, AND circuits 82 to 84.
If all of the output signals of 0 are "0", it is not near the boundary, so the multiplication number 0 is set to the second multiplier 90 and the third multiplier 9
The multiplication number 1 is transmitted for 1. Further, the AND circuit 82
Is “1”, the multiplication number 0.25 for the second multiplier 90 and the multiplication number 0.7 for the third multiplier 91.
5 is sent out. If the output signal of the AND circuit 83 is “1”, the multiplication number for the second multiplier 90 is 0.5.
Is sent to the third multiplier 91.
Furthermore, if the output signal of the AND circuit 84 is "1",
The multiplication number 1 is sent to the second multiplier 90, and the multiplication number 0 is sent to the third multiplier 91.

In this way, the second operator 2
The respective multiplication numbers sent to the multiplier 90 and the third multiplier 91 are stored in the fourth LU in the second and third multipliers 90 and 91.
Density signal and pattern generator 85 sent from T86
The predetermined pattern signals colored with the red coloring material sent from the respective are multiplied, and added by the second adder 93.

As a result, chromatic fine lines in the white area are reproduced by the density signal. Further, the boundary between the white part and the chromatic color part is processed so as to gradually change from the white part to a predetermined pattern corresponding to the hue (chromatic color) of red.

On the other hand, the second computing unit 87 outputs the achromatic color determination circuit 58 when the inverted signal of the achromatic color determination signal is "0".
When it is determined that the pixel of interest is achromatic, the output signal “1” is sent to the first multiplier 89 and the output signal “0” is sent to the third multiplier 91. When the inversion signal of the achromatic color determination signal is "1", that is, when the pixel of interest is determined to be chromatic, a signal corresponding to the boundary determination signal transmitted from the AND circuits 79 to 81 is transmitted. Specifically, if the output signals of the AND circuits 79 to 81 are all “0” based on the determination signal of the achromatic color determination signal, the second computing unit 87 is not near the boundary, and therefore the first multiplier 89. To the third multiplier 91 and the multiplication number 1 to the third multiplier 91. If the output signal of the AND circuit 79 is "1",
The multiplier 0.25 is sent to the first multiplier 89, and the multiplier 0.75 is sent to the third multiplier 91. Also, AND
If the output signal of the circuit 80 is “1”, the multiplication number 0.5 is sent to the first multiplier 89 and the multiplication number 0.5 is sent to the third multiplier 91. Furthermore, if the output signal of the AND circuit 81 is "1", the multiplication number 1
Is sent to the third multiplier 91. In this way, the respective multiplication numbers sent from the second calculator 87 to the first multiplier 89 and the third multiplier 91 are sent from the fourth LUT 86 in the first multiplier 89 and the third multiplier 91. And the red predetermined pattern signal sent from the pattern generator 85 are multiplied by
It is output by the adder 92 and the second adder 93. Accordingly, the boundary between the black component and the chromatic color component is similar to the above-described processing performed on the boundary between the white portion and the chromatic color component, and the hue colored with the red coloring material from the black portion ( It is processed so that it gradually changes to a predetermined pattern according to the chromatic color.

[0050]

As described above, according to the first aspect of the present invention.
According to the image processing device of the invention of claim 1,
A chromatic color and an achromatic color are determined based on the difference between the maximum value and the minimum value of the color separation signal that has been smoothed by the smoothing processing means, and the achromatic color portion other than white of the determined achromatic color is determined as No. 1 colorant, the chromatic color part is displayed by the second colorant, and the hue angle processing means performs a predetermined patterning process according to the hue angle of the chromatic color part. It is possible to express the color information with two different color materials. Further, the color information can also be displayed as an image, for example, in a pattern display predetermined for each hue.

Further, according to the image processing apparatus of the invention of claim 2, in addition to the invention of claim 1, the smoothing processing means smoothes the smoothing processing in accordance with the color separation signal. The smoothing coefficient changing means for changing the coefficient is provided, and the second judging means judges whether the achromatic color judged as the achromatic color by the first judging means is white or black, and further the recognizing means. Recognizes the boundary between the black part and the chromatic color part and the boundary between the white part and the chromatic color part, and the boundary coloring processing means uses the first coloring material and the second coloring material to perform the black part and the chromatic color part. Since the coloring process is performed so that the boundary between the color image and the boundary between the white portion and the chromatic color portion are different, in addition to the effect of the invention of claim 1, even if the chromatic color portion of the color image is a coarse halftone dot, It is possible to display a uniform predetermined pattern according to the hue.

For an image having an achromatic portion such as a black character in the chromatic portion, the boundary between the two can be made clear and the black character can be easily read.

If a thin line of chromatic color exists in the achromatic color portion (white portion), the fine line of the second coloring material (for example, the patterning process corresponding to the chromatic color is not performed). It is processed by the red solid pattern processing in the example), and the color image of the original can be faithfully reproduced.

Further, for example, the boundary between the black portion and the chromatic color and the boundary between the white portion and the chromatic color are not clearly distinguished from each other, and the boundary between the colors is blurred so that the color naturally shifts. The so-called gradation image can be processed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control circuit of an image processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of image processing performed by the image processing apparatus of FIG.

FIG. 3 is a diagram showing an example of image processing performed by the apparatus.

FIG. 4 is a block diagram showing a control circuit of the image processing apparatus according to the second embodiment of the present invention.

FIG. 5 is a block diagram showing a control circuit of a conventional image processing apparatus.

6 is a diagram showing an example of image processing performed by the image processing apparatus of FIG.

FIG. 7 is a diagram showing an example of image processing performed by the apparatus.

[Explanation of symbols]

2, 3, 4, 52, 53, 54 First to third smoothing circuits (smoothing coefficient changing means) 8,58 Achromatic color determination circuit (first determination means) 10,60 Certified color determination circuit (hue angle processing means) ) 13, 14, 64, 65 AND circuit (second determination means) 21, 22, 23, 79, 80, 81, 82, 83, 8
4 AND circuit (recognition means) 25 XOR circuit (boundary coloring processing means) 26 NAND circuit (boundary coloring processing means) 38 OR circuit (boundary coloring processing means) 87,88 Operation circuit (boundary coloring processing means)

Claims (2)

[Claims] 1. An image processing apparatus capable of outputting an image with coloring materials of at least two colors based on an input color separation signal, a smoothing processing unit for smoothing the color separation signal, and the smoothing processing. First determination means for determining a chromatic color and an achromatic color based on the difference between the maximum value and the minimum value of the color separation signal smoothed by the means, and the achromatic color determined by the first determination means. The achromatic color part excluding white is displayed by the first coloring material and the chromatic color part is displayed by the second coloring material, and a predetermined patterning process according to the hue angle of the chromatic color is performed on the chromatic color part. An image processing apparatus comprising: a hue angle processing unit that performs the image processing. 2. The smoothing processing means has smoothing coefficient changing means for changing the smoothing coefficient of the smoothing processing according to the color separation signal, and the first judging means judges that the color is achromatic. Second determining means for determining whether the achromatic color is white or black; recognizing means for recognizing a boundary between the black part and the chromatic color part and a boundary between the white part and the chromatic color part; Boundary coloring processing means for performing different coloring processing on the boundary between the black portion and the chromatic portion and the boundary between the white portion and the chromatic portion using the first coloring material and the second coloring material. The image processing apparatus according to claim 1, wherein: