JP2744437B2 - Color converter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color conversion apparatus that replaces a specific reproduced color with another reproduced color or shifts the color. The present invention relates to a technique for replacing only an image represented by a specific color with another color and reproducing the image, or reproducing the image by shifting the color condition.

2. Description of the Related Art If it is possible to replace only an image represented by a specific color on a document with another color, or to reproduce the image while shifting its color condition, for example, the "red flower" represented on the document may be replaced with a "blue flower". Flowers,
It can be converted to "yellowish red flowers" and is often convenient.

In this case, “red”, “blue” or “yellowish red” recognized by humans is quantitatively converted into RGB data [Red, G
reen, Blue luminance data or density data], and conversely, it is difficult to imagine a color represented as RGB data with a human sense.

Therefore, the present applicant designates an area in a document by inputting coordinates, and uses a color in the area to specify a color to be converted (hereinafter referred to as an extracted color) and a color to be replaced with the color (hereinafter referred to as a replacement color)
Was proposed and the prior application was filed earlier (Japanese Patent Application No. 62-
201169). In this case, the variation within the designated area is set as an allowable range for each specified color.

According to this, the extracted color and the replacement color can be specified by looking at the color appearing on the document, so that the color recognized by the human and the color recognized in the apparatus match.

Problems to be Solved by the Invention Indeed, with this method, a desired effect was obtained for a density gradation image such as a silver halide photograph, but when the sampling density of the input system was increased, the method was not applicable to a halftone dot printed matter. It turned out that the color could not be specified properly.

 The reason will be described with reference to FIG.

Currently, generally used full-color prints are:
It is composed of halftone dots of about 150 to 175 lines (150 to 175 dots / ich). On the other hand, 300 to 400
A sampling density of about dots / inch is employed.
FIG. 11 shows the relationship between these halftone dots and the sampling grid, where ● indicates a halftone dot of Magenta (M), and ○ indicates Yello.
The dots of w (Y) and the grids indicate the pixels to be sampled, respectively. In addition, for convenience of description, 1 to 1
14, numbers are assigned to each pixel, and coordinates of each pixel are designated as (1, a), (8, g) and the like.

This manuscript is drawn with halftone dots of 150-175 lines,
Halftone dots are hardly recognized by ordinary visual observation, and are recognized as a continuous tone light red image. But 300-400dots / inc
Observing this in the sampling of h density, it cannot be said that the ink is uniformly distributed.

For example, the pixels specified by the coordinates (6, b) and (2, f) are both red in color with almost equal amounts of Y and M, but have very different brightness. The coordinates (4.
The pixel specified by e) is in the Y color category, and the pixel specified by the coordinates (4.f) is in the M color category. After all, this image contains M ~ R ~
There will be pixels with a wide range of hues for Y.

In other words, in the halftone dot image, even if it is a macroscopically uniform continuous area, it is a microscopically discontinuous area, and thus there is a disadvantage that the color specified by the pixel specified by the coordinates becomes unstable. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages and to provide a color conversion device capable of stably and appropriately specifying a color even for a halftone original, thereby improving the applicability of the color conversion device. The purpose is to:

Means for Solving the Problems The present invention has noticed that the above-mentioned problem occurs because the sampling aperture is too small with respect to the dot density. Therefore, in the present invention, in order to achieve the above object, a color conversion device that performs the above-described color replacement or shift generates a color signal of a plurality of components in association with each minute region obtained by minutely dividing the original image. Color signal generating means; Micro area specifying means for specifying an arbitrary micro area from the micro-divided original image; Color signals associated with the micro area of interest and the micro area in the vicinity of the specified micro area for each component Signal generating means for generating a signal specifying at least one component from the smoothed signal; and a smoothing signal generating means for generating a smoothed signal in association with the minute area of interest; Shall be provided.

Here, smoothing refers to the color of a minute area near a predetermined minute area of interest (for example, a minute area included in an area represented by 3 × 3, 5 × 5 around the minute area of interest). A process of simply averaging a signal for each component, or a process of smoothing by weighting (for this, a color region signal of a small region of interest is smoothed for each component, and a value of a small region small region in a predetermined neighborhood is smoothed) Also includes the process of replacing with the color signal of
Etc.

According to this, the microscopically discontinuous color area is simulated as a continuous color area by smoothing the sampled color signal, so that it is stable even for a halftone dot document. The color can be appropriately specified, and the applicability of the color conversion device is improved.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

2. Embodiments (1) First Embodiment FIG. 1a is a block diagram showing the arrangement of a color image recording apparatus which embodies the present invention as an example. This apparatus includes a scanner 1, an image processing unit 2, a printer 3, a digitizer 4 for specifying an area, an operation unit 5 for setting processing modes and parameters for processing, and displaying set values and the like. It comprises a system controller 6 for controlling each element.
The image processing unit 2 includes a smoothing circuit 21, a first color system conversion circuit 22, an extracted color designating circuit 23, a replacement color designating circuit 24, a color recognition circuit 25, a color conversion circuit 26, and a second color system conversion. The circuit 27 includes a UCR color correction circuit 28 and a gradation processing circuit 29.

 First, an outline will be described.

When the operator selects the color conversion mode from the operation unit,
It is in a state of waiting for input of area data to specify a color to be converted (hereinafter, referred to as an extracted color) and a color reproduced in place of the color (hereinafter, referred to as a replacement color). During this time, the operator inputs the area data (coordinate data) using the digitizer 4 or the numeric keypad of the operation unit 5 according to the message displayed on the operation unit 5, and sets the range to be included in each color (hereinafter referred to as an allowable range). input.

When the copy start button is pressed after the input of the area data, the pre-scan mode is first set and the printer 3 does not operate. In this mode, the scanner 1 reads the original after separating the original into R (red), G (green), and B (blue), converting the original into 6-bit digital data for each color, and sequentially transmitting the digital data to the image processing unit 2.

The RGB data input to the image processing unit 2 is
After undergoing a smoothing process in order to remove the halftone frequency component in the first color system conversion circuit 22, the HSL color system [H: Hue
(Hue), S: Saturation (saturation), L: Lightness (brightness)]. This will be explained.

First, it should be understood that this color system conversion is a process for facilitating the specification of a color. That is, when color conversion is conventionally performed, the extraction color (R ₁ , G ₁ , B ₁ ) specified in the RGB space is replaced with the replacement color (R ₂ ,
G ₂ , B ₂ ). However, practically, for example, when it is desired to change “red flower” to “blue flower”, in the case of a full-color image, “bright red” or “dark Similarly, the category of “blue” to be designated as a replacement color includes “bright blue” and “dark blue”. In other words, in many cases, the operator specifies a color among the three elements of the color without paying attention to the brightness, so that the operator recognizes the color recognized as specified by the operator and the color specified by the device. A shift occurs between the colors. Therefore,
In the apparatus of this embodiment, the color system conversion processing is performed to decompose the three components, and each of them can be selected independently.
Therefore, even when the operator designates a color without considering the lightness, the above-mentioned shift is almost eliminated if the color designation based on the hue and the chroma component excluding the lightness component from the three elements is selected.

Separately, there is a case where a color such as “red system” is designated. In this case, after specifying the color, it is sufficient to specify the range (permissible range) to be included in the system. However, in the RGB space, not only the permissible range of R, G, B, but also R,
Since the balance between G and B must be considered, it is difficult to specify the allowable range. However, if the color system conversion processing is performed to decompose into three elements as in this embodiment,
This type of color specification becomes possible by selecting the color specification using only the hue component and specifying the color and the allowable range.

As described above, the color system is converted from the RGB system to the HSL system, and the color image can be easily specified by handling the color image in the HSL system. Where H, S, L are L ^* = 116 · (Y / Y ₀ ) ^1/3 −16… (2.1) a ^* = 500 · [(X / X ₀ ) ^1/3 − (Y / Y ₀ ) ^1/3 ]… … (2
・ 1) b ^* = 200 ・ [(X / X ₀ ) ^1/3 − (Z / Z ₀ ) ^1/3 ] …… (2
・ 3) where H = tan ⁻¹ a ^* / b ^* … (3.1) S = (a ^{* 2} + b ^{* 2} ) ¹ /2… ( ^3.2 ) L = L ^* …… (3.3) shall be defined.

However, R, G, B indicate the CIE RGB color system, Where X ₀ , Y ₀ , and Z ₀ are the values of X, Y, and Z on the perfect diffuse reflection surface.

The HSL data converted and generated from the RGB data in the first color system conversion circuit 22 is provided to an extraction color designation circuit 23, a replacement color designation circuit 24, a color recognition circuit 25, and a color conversion circuit 26.

In extraction color specifying circuit 23, as the coordinate data of the pixel of interest matches the coordinate data of the input extraction color specified area by the operator extracted color data HSL data of the target pixel _{(H 1, S 1, L} 1) When the coordinate data of the target pixel matches the coordinate data of the extraction color specific area input by the operator, the replacement color designation circuit 24 stores the HSL data of the target pixel in the replacement color data (H ₂ , S ₂ , L ₂ ) are stored in the storage device in the circuit.

The processing in the prescan mode is as described above, and the color recognition circuit 25, the color conversion circuit 26, the second color system conversion circuit 27, the UCR color correction circuit 28, and the gradation processing circuit 29 do not operate.

When the pre-scan is completed, the main scan mode is set,
The reading by the scanner 1 is started again.

Also in this case, similarly to the above pre-scan, the image data color-separated into RGB is smoothed in the smoothing circuit 21 and converted into the HSL colorant in the first color system conversion circuit 22, and the converted data (HSL data) The extraction color specification circuit 23,
The replacement color designation circuit 24, the color recognition circuit 25, and the color conversion circuit 26 are provided. In this case, however, the extracted color data (H ₁ , S ₁ , L ₁ ) stored in the prescan mode is not used by the extracted color specifying circuit 23 and the replacement color specifying circuit 24 without performing the above-described operation of specifying the color. Is output to the color recognition circuit 25,
Alternatively, it outputs the replacement color data (H ₂ , S ₂ , L ₂ ) to the color conversion circuit 26.

The color recognition circuit 25 compares the HSL data of the pixel of interest inputted in synchronization with the pixel clock with the extracted color data (H ₁ , S ₁ , L ₁ ) given by the extracted color designating circuit 23 and compares them. If the values match within the allowable range specified by the operator, "1" is output as the extraction signal, and if they do not match, "0" is output.

In the color conversion circuit 26, when the extraction signal is “1”, the replacement color data (H ₂ , S ₂ ,
L ₂ ), and outputs the HSL data given from the first color system conversion circuit 22 when the extraction signal is “0”. That is, in the color conversion circuit 26, the replacement color data extracted color data corresponding to the extracted color designated by an operator _{(H 1, S 1, L} 1) corresponds to a replacement color _{(H 2, S 2, L} 2 ).

The data conversion by the color conversion circuit 26 is independent of H, S and L, and the selection is made by the operator. That is, for the reasons described above, the operator performs “color conversion based on hue”, “color conversion based on saturation”, “color conversion based on brightness”, “color conversion based on hue and saturation”, “color conversion based on saturation and brightness”. , “Color conversion by brightness and hue”,
Alternatively, “color conversion based on hue, saturation, and brightness” can be arbitrarily specified. Therefore, for example, when “color conversion by hue” is designated, only the H component is converted, and H ₁ −
Pixels having H data (hue data) satisfying ΔH ≦ H ≦ H ₁ + ΔH (ΔH is an allowable range) are extracted, and the H data is converted into H ₂ .

The HSL data on which the color conversion processing has been performed is subjected to inverse conversion from the HSL color system to the RGB color system in the second color system conversion circuit 27, and is subjected to UCR processing in the UCR color correction circuit. This UCR process corrects the deviation of the spectral characteristics of the color materials used in the printer 3 from the ideal, calculates the amounts of Y, M, C, and B
This is the process for generating the K component.

The data (Y, M, C, B) generated in the UCR color correction circuit 28
K) is binarized by the systematic dither method in the gradation processing circuit 29 and sent to the printer 3. The printer 3 superimposes the Y, M, C and BK colors on the basis of these data and reproduces the color-converted image.

 Next, each processing block will be described in detail.

The smoothing processing in the smoothing processing circuit 21 is performed for each of the RGB data, and one of the digital filters shown in FIGS. 3a to 3d is selected by an operator's specification. Here, a circuit example of a digital filter composed of a 3 × 3 pixel matrix will be described (a part related to one data).

As shown in FIG. 2a, the 3 × 3 pixel matrix is for simultaneously extracting data of 9 pixels arranged two-dimensionally in the main scanning direction and the sub-scanning direction.
A pixel of interest is denoted by the number shown in the figure.

As shown in FIG. 2b, this pixel matrix is composed of line buffers LB1 and LB2 for two lines and data latches L1 to L9 for nine pixels. Here, when the data of the target pixel and its eight neighboring pixels are extracted, a smoothing operation is performed in the circuit shown in FIG. 2c.

The circuit for performing the smoothing operation includes eight adders Add1 to Add8.
And four multipliers Mul1 to Mul4.

Pixels in adders Add1, Add2 and Add5,
And the data of (1) and (2) are added to the result of the addition in the multiplier Mul1 by a coefficient (= 1 in the filter of FIG.
, And set = 2 in the filter of FIG. 3b). The adders Add3, Add4, and Add6 add the data of the pixels,, and, and the multiplier Mul2 adds a coefficient to these addition results (the filter in FIGS. 3a and 3b is set to 1). Multiply. The outputs of the multipliers Mul1 and Mul2 are added in an adder Add7.

In the present embodiment, by forming a set of data to be multiplied in this way, a filter for performing equal weighting on data of pixels having the same distance from the target pixel as shown in FIGS. 3a and 3b Is used to reduce the number of multiplications.

On the other hand, the data of the pixel of interest is multiplied by a coefficient (set to = 1 in the filter of FIG. 3a and set to = 4 in the filter of FIG. 3b) in the multiplier Mul3.
In the adder Add8, the output data of the adder Add7 and the multiplier Mu
The output data of l3 is added, and the result of addition is multiplied by a coefficient (set to = 1/9 in the filter of FIG. 3a and set to = 1/16 in the filter of FIG. 3b) in the multiplier Mul4. This output data becomes the data of the target pixel subjected to the smoothing process.

The above circuit is expanded to 5 × 5 pixels to perform the smoothing processing by the filter shown in FIG. 3c or FIG. 3d, but the description is omitted here. In addition, this embodiment uses RG
B. A circuit for performing a smoothing process using a 3 × 3 pixel matrix and a circuit for performing a smoothing process using a 5 × 5 pixel matrix are provided for each data.

Next, the first color system conversion circuit 22 will be described with reference to FIG. 4a.

This circuit includes nine multipliers Mul11 to Mul33 and three adders Add9 to Add1 for performing the operation of the above-described equation (1).
0, three memories ROM1 to ROM3 for performing the calculations of the above-mentioned equations (2.1) to (2.3) and the (3.1)
To three memories RO for performing the operation of the formula (3.3)
M4 to ROM6 are provided.

Multipliers Mul11, Mul12, Mul13, Mul21, Mul22, Mul23, Mul31,
Mul32 and Mul33 and adders Add9, Add10 and Add11
Converts data R, G, B into data X, Y, Z. In this case, in the above-described equation (1), the coefficient matrix A is set assuming the RGB color system defined by the CIE.
A coefficient matrix C (indicated by matrix element activity cij) for simultaneously correcting differences in spectral characteristics of the color separation filter, illumination system, sensor, and the like of the scanner 1 is used. This coefficient matrix C is set as follows.

First, the data R, G, B obtained from the scanner is corrected to the CIE RGB color system using the following primary correction formula, and the data R ′,
G 'and B' are obtained.

However, And At this time, the data R ', G', B 'obtained by the correction
Is a CIE RGB color system, and can be converted into data X, Y, Z by using the above-mentioned equation (1).

Here, by putting A ・ B≡, Is obtained.

As described above, the data R, G, B obtained from the scanner
, And an operation for converting it into data X, Y, Z is expressed in one step.

The memories ROM1 to ROM3 store data L ^* , a ^*, and b from data X, Y, and Z with reference to a previously stored operation table.
^* , And the memories ROM4 to ROM6 store data from the data L ^* , a ^*, and b ^* by referring to a previously stored operation table.
L, S and H are generated. In the present embodiment, the above-mentioned expressions (2.1) to (2.3) and the expression (3.
Since the conversion by the expressions 1) to (3.3) is a nonlinear operation, the ROM table is used as described above. In each of these conversions, the converted element is determined from one or two elements. Therefore, a relatively small capacity ROM is sufficient. Here, since each element has 8-bit precision, for example, 64 Kw is stored in the memory ROM 2 for generating the data a ^* from the data X and Y.
ord × 8bit = 512Kbit ROM is used.

FIG. 5 shows the configuration of the extraction color designation circuit 23. This circuit includes storage devices L11, L12, and 13, a comparator Cmp1, and the like.

The storage devices L11 and L12 are provided by the operator under the control of the system controller 6 by the digitizer 4 or the operation unit 5.
And the coordinate data (pixel address) x ₁ -addr, y ₁ -addr of the extraction color designation area input from. Comparator Cmp1
Now, this address given to the comparison input port P,
The address x-ad of the target pixel based on the count of the pixel clock and the line clock supplied to the comparison input port Q
dr, y-addr are compared, and if they match, a write control signal is output.

In the pre-scan mode, the pre-scan mode signal is supplied as "1" from the system controller 6, and this write control signal is supplied to the storage device L13 via the AND gate AND1. At this time, since the HSL data of the target pixel is input to the storage device L13, the data is stored in the storage device L13 as the extracted color data (H ₁ , S ₁ , L ₁ ). At the time of the main scan, the prescan mode signal is given as "0" from the system controller 6, so that the data in the storage device L13 is not updated.

The replacement color designating circuit 24 has the same configuration as the above-described extracted color designating circuit 23, and thus the description thereof is omitted here.

See FIG. 6a. As shown in the figure, the color recognition circuit 25 includes three blocks each including a subtractor Sub11, an adder Add12, comparators Cmp11, Cmp12, and an AND gate AND11, and an AND gate AND12. Here, H
The component processing block will be described.

A subtractor Sub11 and adder Add12 includes extracting color data H ₁ from the respective extracted color specifying circuit 23 is supplied with tolerance data ΔH of the system controller 6 operator has specified. The subtractor Sub11 performs a subtraction using these data, and compares the data (H ₁ −ΔH) with the comparator Cmp1.
1 and the adder Add12 performs addition using these data, and supplies data (H ₁ + ΔH) to the comparator Cmp12.

The comparator Cmp11 compares the data H of the pixel of interest with the data (H ₁ −ΔH), and outputs “1” if the former is larger, and outputs “0” if the latter is larger. Similarly, the comparator Cmp12 outputs the data H of the target pixel and the data (H ₁ + Δ
H), if the former is smaller, “1” is output, and if the latter is smaller, “0” is output. These comparators Cmp11
And the output of Cmp12 are combined in an AND gate AND11. In other words, subtractor Sub11, adder Add12, comparator
A window comparator whose center value and width are variable is constituted by Cmp11, Cmp12 and AND gate AND11.

Similar processing is performed for the S component and the L component, and each output is given to the AND gate AND12. AND gate AND12
The data H, is output as "1" to the extracted signal all S and L matches the extracted color data H _1, S ₁ and L ₁ within the allowable range, the different extraction signal any one "0 Output as ".

In this case, if the H component, the S component, or the L component is excluded when the extraction color is specified, the maximum value is set to the permissible data.

The color conversion circuit 26 includes three AND gates AN1 to AN3 and three selectors Sel1 to Sel3 as shown in FIG.

AND gate AN1 is set to H from system controller 6.
Only when the conversion signal is "1" and the extraction signal from the color recognition circuit 25 is "1", "1" is output, and the AND gate AN2 outputs "1" when the S conversion signal from the system controller 6 is "1". twenty five
Only when the extracted signal is "1", the AND gate AN3 outputs "1" when the L conversion signal from the system controller 6 is "1" and the extracted signal from the color recognition circuit 25 is "1". Outputs “1” only to These outputs are input to the selection control terminals of the corresponding selectors.

The selector Sel1 selects and outputs the H data from the first color system conversion circuit 22 when the input of the selection control terminal is "0", and outputs the H data from the replacement color designation circuit 24 when the input of the selection control terminal is "1". and selects and outputs the H ₂ data. Similarly, the selector Sel2 selects and outputs the S ₂ data from S data and the replacement color specifying circuit 24 than the first color system conversion circuit 22 in response to an input selection control terminal, the selector Sel3 the selection control L ₂ data and selects and outputs than L data and the replacement color specifying circuit 24 than the first color system conversion circuit 22 in response to an input terminal.

Therefore, for example, the L-converted signal and the S-converted signal
By setting the 0, H conversion signal to 1, only the hue of the pixel to be color-converted is converted to the hue (H ₂ ) of the replacement color, and the L component and the S component are stored as the original signals.

The second color system conversion circuit 27 is a circuit for inversely converting the HSL system data H ', S', L 'selectively converted by the color conversion circuit 26 into RGB system data. As described above, this configuration is substantially the same as the configuration of the first color system conversion circuit 22, and the description thereof is omitted.

In addition, as the UCR color correction circuit 28 and the gradation processing circuit 29, known ones can be used, and therefore will not be described in detail here.

(2) Modified Embodiment of Each Processing Block FIGS. 3e to 3j show another example of a digital filter. Since these digital filters differ only in coefficients, they can be used as they are in the circuit described above.

FIG. 4b shows a modification in which the first color system conversion circuit 22 is constituted by memories ROM7 to ROM8 storing an operation table. Here, it is assumed that 6-bit RGB data is used.
The RGB data read by the scanner 1 is converted into HSL in one stage using three Kword × 8bit = 2Mbit memories. Of course, the same function can be obtained by using more memory even with a smaller capacity memory. In general, when specifying a color, there is practically no problem even if the accuracy of each component before and after color system conversion is reduced, in consideration of providing an allowable range. However, as described above, since it is considered that the brightness component is often stored before and after the color conversion processing, it is desirable to maintain high accuracy.

FIG. 4c shows a configuration example of a table reference type color system conversion circuit in consideration of the above. Here, the color system conversion processing is performed using the above 5 bits out of the 6 bits of R, G, and B data. However, regarding the L component, considering the contribution ratio of the data R, G, and B to the L component, the data G having the highest contribution ratio is set to 6 bits, and the data R and B are respectively set to 5 bits and 4 bits in the order of the contribution ratio below. The L component is obtained with 6-bit accuracy using a total of 15-bit data. As described above, by considering the contribution ratio, conversion with less input data can be performed without lowering the accuracy. Further, in this example, since the data H, S, and L are obtained from 15-bit RGB data, the memory having a 32 Kword × 8-bit configuration is stored in the ROM 10 and the ROM 11.
And ROM12 are used.

In the case where the color system conversion circuit 22 is configured by using the arithmetic circuit as in the above-described embodiment, the simplification of hardware is maintained while maintaining the accuracy after conversion by considering the contribution ratio. Is possible.

FIG. 6b shows the above-described addition / subtraction and comparison performed in memory ROM2.
1, a modified example of the color recognition circuit 25 performed by the ROM 22 and the ROM 23 is shown. These memory H, the area addressed by H ₁ and [Delta] H, S, or region addressed by S ₁ and [Delta] S, L, in the area addressed by L ₁ and [Delta] L, when satisfying the above conditions ""1(match)" and "0 (mismatch)" at other times. In this case, each memory stores the determination result of match or mismatch when a plurality of ΔH, ΔS or ΔL are set, and a table corresponding to the designated ΔH is referred to.

FIG. 6c shows a modification in which the color recognition circuit 25 is configured using a memory having a 1-word 8-bit configuration. The H component will be described.

Area addressed by the memory ROM 31, H and H ₁ (8
bit) are associated with ΔH _{0 to} ΔH ₇ , and each ΔH
Is stored. From the outputs 0 to 7 of the memory, judgment results for eight kinds of .DELTA.H are output simultaneously. One of them is selected in the multiplexer 31 by a 4-bit select signal Sel _H corresponding to the operator's designation. .

In this case, if the removal of H component to a specific time of the extracted color irrespective non-reference signal is the least significant bit of the select signal Sel _H is set to "1" H, the value of H _1, OR gate OR1 Output "1 (match)", the H component is not referred to. This function can be loaded on the memory POM31, but there are seven types of judgment data.

The block for determining the S component and the L component has the same configuration, and "1" is output as an extraction signal from the AND gate AND31 as long as the determination data of all components match.

(3) Second Embodiment FIG. 1b shows a configuration example of the image processing unit 2 of the second embodiment.

In this apparatus, a "character area" and a "photograph, halftone image area" are distinguished by smoothing processing and gradation processing. This is in view of the inconvenience that the sharpness of the character image is reduced because the smoothing process is performed in the apparatus of the first embodiment regardless of the type of the input image (character image, photographed image, halftone image). This kind of problem is solved by applying a gradation process that emphasizes the resolution performance to the data in the character area without performing a smoothing process on the data.

The details of the area determining unit 2B are described in detail in Japanese Patent Application No. 62-252357, which is an earlier application filed by the present applicant, and the description thereof is omitted here. The separation signal is provided to selectors 2A and 2C.

The selector 2A selects the smoothed data and the non-smoothed data based on the separated signal, and the selector 2C
Selects the output of the first gradation processing circuit 291 and the output of the second gradation processing circuit 292 according to the separation signal. The first gradation processing circuit 291 is a processing circuit for a picture area emphasizing gradation characteristics.
The gradation processing circuit 292 is a processing circuit for a character area that emphasizes the resolution performance. Therefore, the character image is not subjected to the smoothing process and the process that emphasizes the resolution is performed, so that a sharp output image can be obtained. In the picture area (photograph image and halftone dot area), a smoothing process is performed and a process that emphasizes gradation is performed, so that an output image with a smooth gradation is obtained.

(4) Third Embodiment FIG. 1c shows a configuration example of the image processing unit 2 of the third embodiment.

This apparatus is characterized in that, when data of a target pixel is not subjected to color conversion, RGB data which is not subjected to color system conversion processing is used. According to this, when the calculation accuracy of the first color system conversion circuit 22 and the second color system conversion circuit 27 is low, the data of the non-converted pixel is disturbed by the color system conversion process and its inverse conversion process. Is prevented.

In this embodiment, since no extraction signal is input to the color conversion circuit 26, the color conversion processing is performed on the data of all the pixels, but the second color system conversion circuit 27 and the UCR color correction circuit 28
The data R, G, B from the selector 2A and the data R ', G', B 'from the second color system conversion circuit 27 are selected in the selector 2D interposed between the data R, G, B from the selector 2A. You.

(5) Fourth Embodiment FIG. 1d shows a configuration example of an image processing unit 2 according to a fourth embodiment.

This device is configured to be able to designate three colors each of the designated extraction color and the designated replacement color. That is, the extracted color designating circuit 23 of this embodiment includes three sets of the extracted color designating circuit 23 having the configuration shown in the first embodiment, and the replacement color designating circuit 24 has the configuration shown in the first embodiment. The extracted color designation circuit 24 of the configuration includes three sets.

In this case, the operator selects the first extracted color and the first replacement color,
The second extraction color and the second replacement color, and the third extraction color and the third replacement color are associated with each other and designated from the digitizer 4 or the numeric keypad of the operation unit 5.

As shown in FIG. 8, the color recognition circuits 25
It has three sets of color recognition circuits 251 to 253 having the configuration shown in FIG. 6, FIG. 6b or FIG. 6c, and a 2-bit color recognition signal “S ₁ S ₀ ” indicating the matching state with the specified three extracted colors. "Is output. “S ₁ S
“ ₀ ” is “00” when none of the three colors match, “01” when it matches the first extraction color, “10” when it matches the second extraction color,
When it matches with the third extraction color, it becomes “11”. However, if a plurality of extraction colors match, the extraction color specified later is prioritized. Therefore, for example, when the first extracted color and the third extracted color match, “11” is output with priority given to the coincidence with the third extracted color.

The color conversion circuit 26 of the fourth embodiment outputs a color recognition signal “S ₁ S ₀ ”.
The first replacement color (H ₄ , S ₄ , L ₄ ) and the first replacement color (H ₅ , S ₅ ,
L ₅ ), third substitution (H ₆ , S ₆ , L ₆ ) or non-substitution (H, S, L) are selected and output. FIG. 9 shows a color conversion circuit 26 constituted by using a multiplexer MPX for selecting one of four inputs.
Is shown. The multiplexer MPX outputs the color recognition signal “00”.
Data H when, S, L, and the data H _4, S _4, L ₄ when the "01",
The data H ₅ , S ₅ , L ₅ when “10” is set, and the data H ₆ , S ₆ ,
Select the L ₆ to output. In this case, the conversion of the H component, the S component, or the L component may be selected as described above.

(6) Fifth Embodiment FIG. 10 shows a color correction circuit 2E in place of the color conversion circuit 26 in the above-described first to fifth embodiments.

This color correction circuit 2E is a circuit for shifting the hue, saturation, and / or lightness of a specific color. By replacing the color conversion circuit 26 of each of the above-described embodiments with this circuit, for example, a "red flower" Can be shifted relative to each other, such as making the red of "" slightly yellow. In this case, the color to be shifted is designated and extracted using the above-described extracted color designation circuit 23 and color recognition circuit 24, but the replacement data is not designated and the shift data (ΔH, ΔS, Δ
L) is input from a numeric keypad or the like of the operation unit.

Data of each component and shift data are added to adders Add21 and Ad
The selectors Sel21 and Sel2 are added in d22 or Add23.
2 or Sel23 is the data that does not shift according to the extracted signal
H, S, L or shift data H + ΔH, S + ΔS, L + ΔL are selected and output. Of the color components, components that are not desired to be corrected may be set to “0” as the shift amount.

The system includes a color conversion circuit 26 and a color correction circuit.
2E may be provided so that one is selected and used by mode switching. Further, a configuration may be adopted in which color conversion can be performed for some colors and color correction can be performed simultaneously for other colors. For example, in FIG. 1d, a correction value H + Δ is used instead of the output data H ₆ , S ₆ , and L ₆ of the third replacement color designating circuit.
If the configuration is such that H, S + ΔS, L + ΔL is input to the color conversion circuit, the color correction is performed on the data of the pixel of the color that matches the third extraction designated color.

In each of the embodiments described above, the RGB data is configured to be smoothed. However, the same effect can be obtained by configuring the HSL data that has undergone color system conversion to be smoothed for each component.

Further, in the specification of the color and the extraction / replacement, the expressions (1), (2.1) to (2.3) and (3 · 3) are used.
Although the HSL color system defined by the expressions (1) to (3.3) is used, L ^* , a ^* and b ^* defined by the expressions (2.1) to (2.3) are used as they are. Or L ^* , u ^* , v ^* , Munsell color system, YIQ color system, or simple HSL color system introduced in "The 1st Color Engineering Conference"(1984; p91) A considerable effect can be expected by using.

Effects of the Invention As described above, according to the present invention, a microscopically discontinuous color region is imitated as a continuous color region by smoothing a sampled color signal. Color can be stably and appropriately specified even for point manuscripts,
The applicability of the color conversion device is improved.

In addition, as described in the embodiment, by processing the color-separated data by dividing it into a lightness component, a hue, and a saturation component, an extremely convenient color conversion device is obtained.

[Brief description of the drawings]

FIG. 1a is a block diagram showing the structure of the first embodiment of the present invention, FIG. 1b is a block diagram showing the structure of the second embodiment of the present invention, and FIG. 1c is the third embodiment of the present invention. FIG. 1d is a block diagram showing the configuration of the fourth embodiment of the present invention. FIG. 2a is a schematic diagram in which a 3 × 3 pixel matrix used for the smoothing process is developed on a plane. 2b and 2c are block diagrams showing a detailed configuration of the smoothing circuit 21. 3a, 3b, 3c, 3d, 3e, 3f,
3g, 3h, 3i, and 3j are schematic diagrams in which a digital filter used in the smoothing circuit 21 is developed on a plane. FIG. 4a is a block diagram showing a detailed configuration of the first color system conversion circuit 22, and FIGS. 4b and 4c are block diagrams showing modifications thereof. FIG. 5 is a block diagram showing a detailed configuration of the extraction color designation circuit 23. FIG. 6a is a block diagram showing a detailed configuration of the color recognition circuit 25, and FIGS. 6b and 6c are block diagrams showing modifications thereof. FIG. 7 is a block diagram showing a detailed configuration of the color conversion circuit 26. FIG. 8 is a block diagram showing the configuration of the color recognition circuit 25 of the fourth embodiment of the present invention, and FIG. 9 is a block diagram showing the configuration of the color conversion circuit 26. FIG. 10 is a block diagram showing the configuration of the color correction circuit of the device according to the fifth embodiment of the present invention. FIG. 11 is an explanatory diagram for explaining the disadvantages of the prior art. 1: Scanner (color signal generating means) 2: Image processing unit 21: Smoothing circuit (smoothed signal generating means) 22, 27: Color system conversion circuit 23: Extracted color designating circuit (extracted color signal generating means) 24: Replacement color designation circuit (replacement color signal generation means) 25: Color recognition circuit 26: Color conversion circuit 25, 26: (Conversion means) 28: UCR image correction circuit 29: Gradation processing circuit 2A, 2C, 2D: Selector 2B: Area judging section (area specifying means) 3: Printer 4: Digitizer 5: Operation section 4, 5: (micro area specifying means) 6: System controller

Claims (3)

(57) [Claims] 1. A color signal generating means for generating a color signal of a plurality of components in association with each minute region obtained by minutely dividing an original image; arbitrarily selecting a first minute region and a second minute region from the minutely divided original image. A minute area designating means for designating; smoothing a color signal associated with each of the minute area of interest and a minute area in the vicinity of the minute area for each component; A smoothing signal generating means for generating a smoothing signal; an extracting color signal generating means for generating an extracting color signal specifying at least one component from the smoothing signal corresponding to the first minute area; corresponding to the second minute area Replacement color signal generation means for generating a replacement color signal specifying at least one component from the smoothed signal to be processed; a smoothed signal corresponding to a minute area of interest and the extracted color signal There the matching with respect to specific to components, converting means for replacing the said replacement color signal the component replacement color signal to identify the smoothed signal corresponding to the fine small regions; comprises a color conversion device. 2. An image processing apparatus according to claim 1, further comprising an area designating section for designating an area including a plurality of minute areas obtained by minutely dividing the original image, wherein the smoothing signal generating section smoothes a predetermined area based on the designation by the area designating section. The color conversion apparatus according to claim 1, wherein the color conversion is performed. 3. A color signal generating means for generating a color signal of a plurality of components in association with each minute area obtained by minutely dividing an original image; a minute area designating means for designating an arbitrary minute area from the minutely divided original image; Shift setting means for setting a shift amount of at least one component; smoothing a color signal associated with each of the minute region of interest and a minute region in a predetermined vicinity thereof for each component; A smoothing signal generating means for generating a smoothing signal in association with a minute area that is present; an extracted color signal generating means for specifying at least one component from the smoothed signal corresponding to the minute area specified by the minute area specifying means; When the smoothed signal corresponding to the minute region and the extracted color signal match with respect to the component specified by the extracted color signal, the series of the smoothed signal corresponding to the minute region is extracted. The component number is set quantity, shifting means for shifting set a shift amount; comprises a color conversion device.