JPH07203235A - Method and processor for color picture - Google Patents

Abstract

PURPOSE:To decide a color reproduction, range for each output device with a small memory capacity by deciding whether or not an object picture signal is included in a color reproduction range of an output device based on eight primary color measurement data from plural output devices and a three primary color picture signal stored in a memory section. CONSTITUTION:A picture memory 101 stores a picture signal being a processing object. The picture signal is expressed in a density of three primary colors such as R, G, B. On the other hand, an output device designation processing section 104 outputs measurement data of eight primary colors corresponding to an output device among plural output devices. The eight primary color measurement values are values with high saturation such as R, G, B, Y, M, C, W (white) and K (black). Uniform color space conversion processing sections 102, 105 convert the picture signal from the memory 101 and the eight primary color measurement values from a table 103 respectively into a same space coordinate. A plane definition section 106 selects three color coordinates to define 12 ways of planes. A decision section 107 decides whether or not an object picture signal is included in a color reproduction range of the output device based on the output of the definition section 106 to provide the output of a decision flag 108.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image processing apparatus and method for performing processing based on the reproduction range of an output device.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and the like, color images have been processed or created on a computer and observed on a color display, or the created image is printed on paper by a hard copy device or an inkjet printer. Opportunities to output are increasing.

In this case, the color reproduction ability varies depending on the output device (output device such as a hard copy device or ink jet printer). For example, it is not guaranteed that the color observed on the monitor is output as a hard copy. There is no. In particular, the color reproduction range of a hard copy device is generally narrower than that of a color monitor, so colors that can be reproduced on the monitor but are outside the color reproduction range of the hard copy device cannot be reproduced on the hard copy. In many cases.

[0004]

In order to solve the above problems, for example, whether or not combinations of color signals of all color images are included in the color reproduction range of the output device is obtained in advance. A method is conceivable in which a look-up table is created and processing such as issuing a warning when the input color signal is outside the color reproduction range.

In this case, however, the number of color signal combinations is enormous, and the storage capacity of the lookup table becomes very large. Further, when there are plural types of output devices, the table is held for each of them. Since it is necessary, there is a problem that the required storage capacity is further increased.

The present invention has been made in view of the above points, and an object of the first invention of the present application is to obtain a color reproduction range of an output device with a small storage capacity.

A second object of the present invention is to determine whether or not a color signal of an image is included in a reproduction range by a simple process.

[0008]

In order to achieve the above object, the present invention has the following constitution.

According to a first aspect of the present invention, there is provided a generating means for generating a plurality of color image data corresponding to a color saturation that is substantially limitable for output in an output device, and a plurality of color image data having different hues, and a plurality of the plurality of color image data. And an interpolation generating unit that interpolates and generates a boundary surface of a reproduction range that can be output by the output device based on the color image data.

In a second aspect of the present invention, in a color image processing apparatus for converting a color image signal into output data of an output device for visualizing output, primary color data determined based on colors that can be output by the output device. And a conversion means for converting the color image signal into data belonging to the same color space, a plane in the color space defined by the value of the converted primary color data, and a plane after the conversion. It is characterized by further comprising: a determination unit that determines whether or not the color indicated by the color image signal is a color that can be output by the output device according to the positional relationship with the value of the color image signal.

[0011]

【Example】

(First Embodiment) FIG. 1 is a block diagram showing the flow of color reproduction range determination processing according to an embodiment of the present invention.

In FIG. 1, 101 is an image memory for storing an image signal to be processed, and the image signal is generally represented by density values of three primary color signals such as R, G and B. On the other hand, 103 is a table for storing the measured values of the eight primary colors in the output device.
4. For example, the measurement value data of eight primary colors corresponding to the output device designated by the designation unit for selecting from a plurality of output devices is output. Here, the measured values of the eight primary colors are R (red), G (green), and B that can be output by the output device.
(Blue), Y (Yellow), M (Magenta), C (Cyan), W
(White) and K (black) are the colors with the highest degree of saturation, that is, the colors with the highest saturation are measured. For example, C, M, Y is 3
The measured values of these primary colors corresponding to the primary color hard copy device are the colors actually printed when the area ratios of R, G, B, C, M, Y, W, and K are set to the following values. The value is measured with a colorimeter.

The above-mentioned R, G, B, C, Y, M,
C, W and K are recording materials C, M, Y and K used in the output device.
It corresponds to the primary and secondary colors of.

R: C = 0%, M = 100%, Y = 100% G: C = 100%, M = 0%, Y = 100% B: C = 100%, M = 100%, Y = 0 % Y: C = 0%, M = 0%, Y = 100% M: C = 0%, M = 100%, Y = 0% C: C = 100%, M = 0%, Y = 0% W : C = 0%, M = 0%, Y = 0% K: C = 100%, M = 100%, Y = 100%

Both 102 and 105 are image memories 101.
Is a uniform color space conversion processing unit that converts the color signal value data of the eight primary colors (hereinafter, simply referred to as the eight primary color data) from the color measurement value table 103 into the same uniform color space coordinate value. As uniform color space coordinates, L ^* , a ^* , b ^* and L ^* , u ^* , which are defined by CIE (International Commission on Illumination),
v ^* or the like can be used. Reference numeral 106 denotes a plane defining unit that selects coordinate values of three colors in a predetermined combination as will be described later from the eight primary color data converted into the uniform color space coordinate values and defines twelve plane expressions. Reference numeral 107 indicates that the target image signal is included in the color reproduction range of the output device based on the uniform color space coordinate values of the target image signal output from the conversion processing unit 102 and the equations of the twelve planes defined by the plane definition unit 106. The color reproduction range determination unit determines whether or not the color reproduction range is determined and outputs the determination flag 108. Since the determination flag 108 is output for each pixel of the target image, it may be stored in another image memory, or may be input to a counter to count the number of pixels not included in the color reproduction range. May be.

By storing the determination flag in another image memory, it is possible to easily switch between the process of notifying the user of pixels outside the color reproduction range of the output device and the process of outputting pixels outside the color reproduction range by the normal process. You can

Further, by counting the number of pixels outside the color reproduction range, processing corresponding to the number of pixels outside the color reproduction range, that is, processing according to the influence of pixels outside the color reproduction range on the image is performed. be able to.

Next, a method of defining twelve planes in the plane defining unit 106 will be described.

FIG. 2 is a schematic diagram showing the distribution of the eight primary color data on the uniform color space. The color gamut of the output device can be expressed as the inside of a modified hexahedron having the eight primary color data of Y, M, C, B, G, R, W, and K shown in FIG. Such a color signal is a color that can be reproduced by the output device. Therefore, if the surface of this modified hexahedron is represented by a plurality of planes and it is determined whether or not it is inside the planes,
It will be known whether the target color signal can be reproduced by the output device.

Since the plane in the three-dimensional space can be obtained by designating three points, if three adjacent points among the vertices of the eight primary color data shown in FIG. 2 are selected to define the plane, the surface of the deformed hexahedron Can be defined as one. For example, W for 3 points,
By selecting R and Y, the surface of the shaded area shown in FIG. 3 can be defined. Similarly, if three points are selected in the following twelve ways and twelve surfaces are defined, all surfaces covering the entire hexahedron can be defined.

1: W, R, Y 2: W, Y, G 3: W, G, C 4: W, C, B 5: W, B, M 6: W, M, R 7: K, R , Y 8: K, Y, G 9: K, G, C 10: K, C, B 11: K, B, M 12: K, M, R

A determination method using the 12 planes defined above will be described below.

Generally, the plane in the X, Y, Z three-dimensional space can be expressed by the following equation.

Ai.X + Bi.Y + Ci.Z + Di = 0 Ai, Bi, Ci, Di are coefficients determined by the way of defining the plane, and these coefficients are defined for each of the above 12 ways (i = 1. ~ 12). X, Y, Z
Is a variable, in this case the uniform color space coordinates L ^* , a ^* ,
Corresponds to b ^* .

Now, one point P (see FIG. 3) is selected on the achromatic color axis (L ^* axis) of the uniform color space. It is clear from FIG. 3 that when P is selected as an appropriate lightness (L ^* ) value such as an achromatic color point, P is included in the color reproduction range in most output devices. Here, the coordinates of P are (L0,
a0, b0), and the target image signals L ^* , a ^* , b ^*
The coordinate Q is represented as (L, a, b). At this time, these 2
By substituting one coordinate value into the equation of the i-th plane, the following two values S1 and S2 are obtained.

S1 = Ai * L0 + Bi * a0 + Ci * bo + Di S2 = Ai * L + Bi * a + Ci * b + Di

Therefore, if the target image signal is within the color reproduction range, since P is within the color reproduction range, the coordinates Q (L, a, b) of the target image signal are the i-th coordinates. It should be on the same side as P with respect to the plane. That is, the above S1 and S2 have the same sign (when included in the plane, the above value is 0). On the other hand, when it is out of color reproduction, P and Q are on opposite sides of the plane, and S1 and S2 have different signs (see FIG. 4).

That is, one plane (i) can be judged from the inside or outside of the reproduction range under the following conditions.

If S1 ・ S2 ≧ 0, it is within the reproduction range. If S1 ・ S2 <0, it is outside the reproduction range.

Therefore, if the above determination is performed for all 12 planes and it is determined that all 12 planes are within the reproduction range (S1, S2 ≧ 0), the color of the target image signal is determined by the output device. It is included in the color reproduction range.

That is, it is possible to faithfully reproduce the color by the output device based on the target image signal.

On the other hand, if it is determined that even one of the 12 planes is outside the color reproduction range (S1 · S2 <0),
This means that the color of the target image signal is not included in the color reproduction range of the output device.

That is, the output device cannot faithfully reproduce the color based on the target image signal.

(Second Embodiment) FIG. 5 is a schematic view showing a uniform color space according to another embodiment of the present invention.

In the above embodiment, the color gamut of the output device is defined as substantially inside the modified hexahedron, but here, as a more accurate method, the color gamut is divided into 12 modified tetrahedrons. I will define it. That is,
As shown in FIG. 5, a tetrahedron 501 is defined from the three points used in the first embodiment and the point P on the achromatic axis, and the four vertices of the tetrahedron (W, R, Y, P in the figure) are defined. ) Center of gravity S (50
2) is newly set.

Accordingly, one tetrahedron is defined as an interior surrounded by four planes which are the following four triangles.

1: ΔWYR 2: ΔWPR 3: ΔWPY 4: ΔPRY

Since the center of gravity S is included in the inside of the tetrahedron, whether or not the input image signal is included in the inside of one tetrahedron is the same as in the first embodiment, L, a and b of the target image signal.
This can be understood by checking whether the coordinates are located on the same side as S on the above four planes. This tetrahedron is defined for all twelve planes used in the first embodiment and a judgment is made, and it is judged that a color signal value not included in any tetrahedron is outside the color reproduction range of the output device. be able to.

(Third Embodiment) FIG. 6 is a schematic view showing a uniform color space according to still another embodiment of the present invention.

In this embodiment, whether or not the target image signal is included in the color reproduction range of the output device is determined by the method described in the first or second embodiment. The signal is replaced with a color signal within the reproduction range and output.

As shown in FIG. 6, L of the target image signal,
The a and b coordinates Q are determined in the same manner as in the first embodiment.
Consider the case where it is determined that Q is located on the opposite side of P with the i-th plane ΔWRY sandwiched therebetween. At this time, when the coordinates of the intersection H (601) of the straight line PQ and the plane (i) are obtained, it is found that H has a hue on the uniform color space equal to Q and is a color reproducible by the output device. Recognize.

Here, the hue is a value represented by the following formula by the a ^* and b ^* coordinates of the uniform color space.

Hue = arctan (b ^* / a ^* )

By inversely converting the coordinate values of H thus obtained into the color signal values (R, G, B) of the input image and rewriting the data in the image memory, the processing for all pixels is completed. At that time, all the color signal values in the image memory are only the colors included in the color reproduction range of the output device.

In each of the above-mentioned embodiments, the hardcopy device for printing on paper or the like, the ink jet printer or the like is used as the output device, but the output device according to the present invention may be a CRT display, a liquid crystal display or the like. Good. That is, the present invention can be applied to image signal conversion between devices having different color reproduction capabilities.

As is apparent from the above description, according to each of the above-described embodiments, the primary color data determined based on the colors that can be output by the output device and the image signal are compared in the same color space, At this time, the comparison is performed according to the positional relationship between the area defined by the primary color data on the color space and the image signal, and it is determined whether the image signal is a color that can be output by the output device.

As a result, it is possible to determine whether or not the color signal of the image is included in the color reproduction range by a simple process based on only the primary color data based on the output device.

The above processing can be performed by dedicated hardware or software, but in this case, the capacity of the memory can be reduced as compared with the conventional case.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIG. 7 in which the parameters representing the color reproduction range of the printer are appropriately changed by an instruction from the host computer.

As shown in FIG. 10, a plurality of color copying machines 302 and 307 and printers 303 and 304 are connected as print output means of the host computer 301.

Further, a plurality of scanners 305 and 306 are connected as input means of the host computer 301.

The host computer sequentially executes the procedure shown in FIG. 7 according to a user's instruction. First, in 701, a printer calibration mode for updating the color reproduction parameter of the printer is selected. Then, on the display monitor of the computer, FIG.
A screen like is displayed. Since a plurality of connected device names are displayed in 802, a target device is selected (702). Next, when a portion of 803 for designating 8-primary color printing is clicked using a pointing device such as a mouse, a patch of 8-primary color is output from the designated device in a form as shown in FIG.

Here, the eight primary colors are R that can be output by the output device.
(Red), G (green), B (blue), Y (yellow), M (magenta), C (cyan), W (white), K (black), which have the highest degree of saturation, For example, in a hard copy apparatus using C, M, and Y as the three primary colors, each patch in FIG. 9 is a color that is printed out by setting the area ratio of C, M, and Y to the following values.

901 = R: C = 0%, M = 100%, Y = 100% 902 = G: C = 100%, M = 0%, Y = 100% 903 = B: C = 100%, M = 100%, Y = 0% 904 = Y: C = 0%, M = 0%, Y = 100% 905 = M: C = 0%, M = 100%, Y = 0% 906 = C: C = 100 %, M = 0%, Y = 0% 907 = W: C = 0%, M = 0%, Y = 0% 908 = K: C = 100%, M = 100%, Y = 100
%

When the patch is output and the setting button 805 is clicked, a color reproduction range setting screen 806 is displayed. The user places the output patch on the platen of the copying machine and clicks the patch reading button 807. Then, the computer sends a control signal for the reader section of the copying machine to scan and read the original on the platen (70
4). The computer automatically cuts out a patch area from the read original image and obtains RGB signal values of eight primary color portions (705). The obtained RGB signal values are converted into uniform color space coordinate values such as L ^* , u ^* , v ^*, etc. by a predetermined conversion formula (706). Here 704 ~
In 706, the reader section of the copying machine is used to obtain the uniform color space coordinate values of the eight primary color patches, but of course a colorimeter connected to a computer may be used,
Alternatively, the patch may be measured using an off-line colorimeter and the measurement result may be input using a keyboard or the like.

When the above is completed, the color reproduction range display button 808 is clicked. Then, the uniform color space coordinate values of the just-measured 8 primary color patches are displayed on the color reproduction range display screen 811 together with the coordinate axes (707). Although various display methods are possible, for example, 12 planes determined by 8 primary colors are displayed by a wire frame, or each surface is displayed by coloring using a shading method well known in the field of computer graphics. It is possible.

If the displayed data is good, a color reproduction range save button 809 is clicked. As a result, the color gamut data of the output device is updated and saved (7
08).

After that, whether or not the input color image signal is included in the color reproduction range of the output device set here is determined by the above-described method based on the updated eight primary color data. .

Further, in the case of the system as shown in FIG.
When setting output devices, the color reproduction range of each output device is also an important factor. Therefore, as shown in FIG. 8, by selecting a device, displaying the color reproduction range of the selected device, and notifying the user, the user can select an output device having an appropriate color reproduction range according to the application. it can.

Specifically, when the output image data is mostly yellow images, an output device having a wide color reproduction range for yellow may be selected.

(Fifth Embodiment) A fifth embodiment will be described below with reference to the drawings. The fifth embodiment is a modified example of the process of replacing the image signal outside the color reproduction range with the color signal within the reproduction range and outputting the image signal, which is described in the third embodiment. The processing is changed according to the number.

FIG. 11 is a conceptual diagram of this embodiment, and FIG. 12 is a flowchart showing the flow of processing.

FIG. 11 shows that a faithful color reproduction area and a mapping color reproduction area exist in the device color reproduction area, and the two boundaries, the mapping boundary, are controlled according to the input image, and the outside of the mapping boundary. It indicates that the input color signal of is mapped to the mapping color reproduction area.

In FIG. 12, in step 1, an image is input from an image input device such as an image scanner, a video camera, a CG editor, and an image file, and in step 2, the image reading characteristics of the image scanner and device colors such as a monitor and a printer. Data representing the characteristics of the image output device (hereinafter referred to as “profile”) such as the reproduction area and the γ curve of the monitor are input, and each pixel of the image represented by the color signal input in step 1 Whether or not it exists inside a certain area of the spatial coordinate system is determined by the method of the first or second embodiment, and it is determined in step 4 that it is outside the device color reproduction area input in step 2 in step 3. The number of judged pixels is counted by setting a flag as described in the first embodiment. In step 5, the position of the mapping boundary is determined from the ratio of the number of pixels outside the device color reproduction area and the total number of pixels obtained in step 4, and in step 6 it is determined to be outside the device color reproduction area by step 3. Among the pixels, the pixel that has the greatest influence on the color space compression, that is, the value of the relative position of the pixel having the largest relative position with respect to the boundary of the device color reproduction area and the position of the mapping boundary determined in step 5. A mapping coefficient, that is, a coefficient for mapping a color signal outside the mapping boundary to the mapping color reproduction area is obtained from the above, and step 7 determines whether or not the input color signal exists outside the mapping boundary determined in step 5. Then, in step 8, the color signal determined to exist outside the mapping boundary in step 7 is set to the mapping obtained in step 6. With several, for example mapped to a region between the mapping boundary and the device color reproduction area by the calculation described later, and outputs the image obtained by the step 9, step 7 monitor, to the image output apparatus such as a printer.

The processing performed in each step for each pixel of the image input in step 1 will be specifically described below.

(Determination of Inside / Outside of Device Color Reproduction Area) It is determined in step 3 whether or not the input color signal exists inside the device color reproduction area obtained in step 2 for each pixel.

For example, if the device color reproduction area is R (re
d), G (green), B (blue), Y (yel)
low), M (magenta), C (cyan), W
When defined by eight points of (white) and K (black), the eight points are converted into coordinate values of the color space coordinate system CIE LAB, and R, G, and
A device color reproduction area is approximated by a dodecahedron formed from six points B, Y, M, and C and a ridge of W and K, and a point existing inside the device color reproduction area for the dodecahedron, for example,
If the convergence point and the point of the input color signal to be determined are on the same side, it is determined that the pixel color is inside the device color reproduction area, and if it is on the opposite side, it is outside.

It should be noted that 1 indicating the device color reproduction area described above.
The dihedron is equivalent to the modified hexahedron in the above-described embodiment.

(Determination of Mapping Boundary) In step 4, the number of input color signals determined to be outside the device color reproduction area is counted in step 4.

In step 5, the ratio of the number of input color signals outside the device color reproduction area to the total number of input color signals is calculated, and the coefficient α that defines the position of the mapping boundary is controlled based on the value of the input color signal ratio outside the area. To do. The position of the mapping boundary is determined by multiplying the boundary of the device reproduction area. However, as shown in FIG. 15, the possible range of α is b ≦ α ≦ 1 (b is a predetermined constant), and the value of α calculated based on the value of the out-of-region input color signal ratio is b. If smaller, the value of α is set to b, which is the minimum value that α can take.

For example, when all the input color signals exist within the device color reproduction area, the out-of-area input color signal ratio is 0, α = 1, and the mapping boundary is equal to the boundary of the device color reproduction area. Control to become. On the contrary, when all the input color signals exist outside the device color reproduction area, the out-of-area input color signal ratio is 1, and α = 0 in the calculation, but α can be taken as described above. Since the value is b ≦ α ≦ 1, α is set to b, which is the minimum value that α can take, and the mapping boundary is controlled to be a position reduced by multiplying the boundary of the device color reproduction area by b toward the convergence point. To do.

Here, the convergent point is the convergent point of the color space compression, for example, the center of the color space coordinate system.

As described above, as the number of input color signals outside the device color reproduction area increases, α approaches b, and the mapping boundary approaches the convergence point. Therefore, the faithful color reproduction area becomes smaller and the mapped color reproduction area becomes wider. Input color signals outside the device color reproduction area can be mapped while maintaining color continuity. Further, as the input color signal outside the device color reproduction area is smaller, α approaches 1, and the mapping boundary approaches the same position as the device color reproduction area. Therefore, the faithful color reproduction area becomes wider and the mapping color reproduction area becomes smaller. , Most of the input color signals within the device color reproduction area that can faithfully reproduce colors are output unchanged.

(Mapping Coefficient) The mapping coefficient is determined in step 6 from the pixels determined to be outside the device color reproduction area in step 3.

For example, when color space compression is performed along a locus connecting a color signal outside the area and the convergence point, as shown in FIG. 4, the absolute position of the intersection of the locus and the surface of the device color reproduction area: Pg, Absolute position of intersection of the locus and mapping boundary: Pg ', absolute position of color signal outside mapping boundary: Pg
If the absolute position of b and Pb after color mapping is Pb ′, the relative position Pr of the color signal can be obtained by Pr = Pb / Pg (1.1).

By calculating with the relative position, all the input color signals are standardized with the device color reproduction area as a reference.
It can be compared with rmax, and mapping can be performed in consideration of the characteristics of the input image.

The relative position of Pg obtained by the equation (1.1): Pgr, the relative position of Pg ': Pgr' The relative position of Pb: Pbr, the relative position of Pb ': Pbr'.

Further, the relative position obtained by the equation (1.1) is obtained for the color signals outside all the device color reproduction areas, and the maximum value is set as the relative position Pbrmax of the color signal farthest from all the device color reproduction areas. .

In FIG. 14, the absolute position of Pbrmax is Pbmax, and the point where Pbmax is moved to the convergence point and the locus of Pb is Pbmax '.

Relative position Pbr 'after mapping Pbr'
Is Pbr '= (Pgr-Pgr') / (Pbrmax-P
gr ′) × (Pbr−Pgr ′) + Pg ′ ... (1.2).

However, in the equation (1.1), Pgr = 1, Pg
r ′ = α.

Since the reference position for displaying the relative position is Pgr ', both sides of the equation (1.2) are Pgr'.
When divided by, the relative position Pr ′ of Pbr ′ after mapping the color signal Pbr with respect to the mapping boundary Pgr ′ is

[0083]

[Outer 1] Here, since Pgr = 1 and Pgr ′ = α in the equation (1.1), Pr ′ = A · (Pbr−1) +1 (1.4) where A is a mapping coefficient and A = (1 / α-1) / (Pbrmax / α-1) ...
It is calculated by (1.5).

In step 6, the above-mentioned mapping coefficient A is determined from the above-mentioned Pbrmax and α.

Further, in the equation (1.2), four variables are required for each pixel in order to calculate Pbr ', but the equation (1.
By transforming it into 4), one variable is required for each pixel if the mapping coefficient A is calculated once. Therefore, the equation (1.
By transforming 2) into equation (1.4), it is possible to efficiently perform mapping in step 8 described later.

(Mapping) In step 8, if the input color signal is outside the mapping boundary, it is uniformly compressed and mapped in the mapping color reproduction range by the equation (1.4).

On the other hand, when the input color signal is within the mapping boundary, the process of changing the color characteristic of the input color signal is not performed.

Since the mapping boundary is determined by executing step 5 described above, by executing steps 6, 7 and 8, as the number of input color signals outside the device color reproduction area increases, the faithful color reproduction area increases. Becomes smaller and the mapped color reproduction area becomes wider, so that color signals outside the device color reproduction area can be mapped while maintaining color continuity. Also, the smaller the input color signal outside the device color reproduction area, the wider the faithful color reproduction area and the smaller the mapped color reproduction area, and the larger the input color signal within the device color reproduction area that is originally capable of faithful color reproduction. The part can be output without change.

Therefore, an output image faithful to the input image is obtained in the faithful color reproduction area, and an output image in which color continuity is maintained and color balance is not lost outside the mapped color reproduction area.

An example of the series of processes described above is R, G,
The case where the device color reproduction area is defined by eight points of B, Y, M, C, W, and K will be described below.

Based on the device color reproduction area input in step 2, it is determined in step 3 whether or not the input color signal exists inside the device color reproduction area, and in step 4, the number of pixels outside the device color reproduction area is determined. After counting, the out-region input color signal ratio is obtained in step 5, α is obtained based on the value, and in step 6, the mapping coefficient is obtained from α and Pbrmax.

If the mapping boundary is set to a position reduced by α toward the convergence point, 8 points are reduced by α toward the convergence point in the color space coordinate system. In step 7, it is determined whether the input color signal exists inside the mapping boundary based on the eight points.

In step 8, if outside the mapping boundary, the position after mapping is obtained using the distance from the convergence point and the mapping coefficient.

For example, when color space compression is performed along a locus connecting a color signal outside the mapping boundary and the convergence point, the intersection of the locus and the mapping boundary is obtained, and the relative position is calculated by the equation (1.1). . Next, the relative position is calculated by the equation (1.
Substituting in 4), the position after mapping is obtained.

On the other hand, if it is within the mapping boundary, the process of changing the color characteristic of the input color signal is not performed.

In step 9, the image after the color space compression processing is output.

(Modification of Fifth Embodiment) Next, as a modification of the fifth embodiment, a case where the image processing method described in the above embodiment is realized by hardware will be described.

FIG. 16 is a block diagram showing an example of a schematic internal configuration of a system for carrying out the image processing method according to the present invention. The system according to this embodiment includes an image input device 1, an image output device 11, a device color reproduction area, an external input device 12 for inputting a profile of the image output device 11 such as a monitor γ curve, and an image processing device 100. ing.

In the image processing apparatus 100, 2 is an interface for receiving the color signal from the image input apparatus 1,
Reference numeral 3 is a frame memory for storing the input color signal of one frame for each R, G, B. Reference numeral 4 is a selector, and the R, G, B color signals from the frame memory 3 are first stored for each frame for one frame. , To the mapping control circuit 6, and then
The color signal of the same frame is output to the mapping circuit 5.
The mapping control circuit 6 determines the inside / outside of the device color reproduction area data described above, determines the mapping boundary, and calculates the mapping coefficient from the image data and the device color reproduction area data from the CPU 7, and the mapping boundary data 200 And the mapping coefficient data 201 are output. On the other hand, the mapping circuit 5 performs the above-mentioned mapping based on the mapping boundary data 200 and the mapping coefficient data 201 input from the mapping control circuit 6, and outputs the mapped color signals R ′, G ′, B ′. The frame memory 3 is reset by the CPU 7 when the output of all color signals of one frame to the color mapping circuit 5 is completed, and starts writing a new color signal. 10
Is an interface for transmitting the input R ′, G ′, B ′ color signals to the image output device 11. 7 is a CPU
The image output device 1 such as the device color reproduction area from the external input device 12 and the γ curve of the monitor stored in the RAM 8
Based on the program stored in the ROM 9, the profile data of No. 1 is output to the mapping control circuit 6, and the frame memory 3, the selector 4, and the mapping control circuit 6 are controlled.

FIG. 17 is a block diagram showing the structure of the mapping control circuit 6 in detail.

The separator 20 determines the maximum relative position determination circuit 21 and the α determination circuit 2 based on the color signal input from the selector 4.
It outputs to both 2. The maximum relative position determination circuit 21 uses the R, G, B absolute position color signals input for each pixel and the CPU.
Based on the device color reproduction area data from 7, the relative position with respect to the device color reproduction area is obtained for all pixels, and the maximum relative position Pbrmax is output. On the other hand, the α determination circuit 22 counts the number of input pixels and the CPU 7
Based on the device color reproduction area data input from
The inside / outside of the device color reproduction area is judged for the input color signal, the number of pixels outside the device color reproduction area is counted, the ratio of the number of pixels outside the device color reproduction area to the total number of pixels is calculated, and the out-of-range pixel ratio is calculated. The value of α (αmax ≦ α ≦ 1) that controls the mapping boundary is calculated and output from the value. The mapping coefficient circuit 23 is an arithmetic circuit that executes the equation (1.5) for obtaining the color mapping coefficient A from the value of Pbrmax input from the determination circuit 21 and the value of α input from the determination circuit 22. Output to the color mapping circuit 5. The faithful color reproduction range determination circuit 24 obtains faithful color reproduction region data from the value of α input, the device color reproduction region data input from the CPU 7 and the value of α input from the determination circuit 22, and the color mapping circuit Output to 5.

FIG. 18 is a block diagram showing details of the mapping circuit 5.

The faithful color reproduction range determination circuit 30 determines whether or not the input absolute position color signal is within the faithful color reproduction area based on the mapping boundary data 200 from the mapping control circuit 6, and within the faithful color reproduction area. If it is outside the faithful color reproduction area, it is output to the mapping arithmetic circuit 31. The mapping arithmetic circuit 31 is
The relative position based on the faithful color reproduction area is obtained based on the mapping boundary data 200 input for the absolute position color signal input from the determination circuit 30. The relative position P ′ after mapping is obtained by an arithmetic circuit that executes the equation (1.4) using the relative position and the input mapping coefficient data 201, and absolute position conversion is performed to the interface 10 to obtain the pixel after color mapping. Data R ', G',
Output as B '. The delay circuit 32 maps the absolute position color signal input from the determination circuit 30 to the mapping arithmetic circuit 31.
Is a circuit that delays by the time required for calculation, and is composed of, for example, a line memory.

As another modification, a case where the above-described image processing method is implemented by using other hardware will be shown.

FIG. 19 is a block diagram showing an example of a schematic internal configuration of a system for carrying out the color space compression method according to the present invention. The system of this embodiment includes an image input device 1, an image output device 11, an image processing device 101, and a computer 1.
It is composed of three.

In the image processing apparatus 101, 2 is an interface for receiving an input color signal from the image input apparatus 1, 41 is an input color signal to be mapped based on the mapping data input from the interface 42. Is a mapping memory that outputs the
Composed of AM. Reference numeral 10 is an interface for transmitting an input color signal after mapping to the image output device, and 42 is an interface for receiving mapping data from a computer.

The computer 13 uses the image output device 11
Based on the device color reproduction area and the input color signal from the image input apparatus 1, a mapping boundary is determined, mapped data corresponding to the input color signal is created, and a lookup table is created in the mapping memory 41 via the interface 42. Form.

In the above embodiment of the present invention,
Although the CIE L, a, and b color spaces and the R, G, and B color spaces are used, for example, the CIE L, u, v, and Y, I, and Q color spaces may be used.

Further, the number of pixels outside the device color reproduction area of the counting means of the embodiment and the maximum relative position of the mapping coefficient determining means may be obtained by sampling the input signals instead of obtaining them from all the input color signals.

The mapping method is as shown in equation (1.4).
The color space compression is not limited to the linear color space compression described above, and may be non-linear.

The value of the above-mentioned specific color signal is Pbrm.
Not limited to ax, it may be any one that shows the characteristics of the input image such as the color signal of the maximum frequency.

Also, in the above-described embodiment of the present invention,
The above-mentioned image processing is performed for one frame. However, for example, when images with different characteristics such as a photograph and a document are mixed in one frame, region separation is performed and each region is separated. The image processing described above may be performed.

Further, in the above-mentioned embodiment, the mapping boundary can be controlled surely by controlling the mapping boundary according to the number of pixels of the input color signal outside the predetermined color space.

Furthermore, by controlling the mapping boundary based on the value of a specific input color signal, it becomes possible to perform mapping in accordance with the characteristics of the input image.

As described above, according to the fifth embodiment of the present invention and its modified example, by controlling the mapping boundary based on the input color signal, the color continuity can be achieved even outside the device color reproduction area. A good color image can be reproduced while maintaining.

(Sixth Embodiment) The sixth embodiment will be described in detail with reference to a modification of the above-described embodiment, which is a modification of the parameters representing the color gamut of the printer in the fourth embodiment.

The color reproduction range of the output device changes due to environmental differences and changes over time.

The purpose of this embodiment is to effectively use the color gamut that can be actually expressed by the output device by changing the parameter representing the color gamut in response to the change in the color gamut.

The sixth embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 20 is a diagram showing an example of the image processing apparatus of this embodiment. The input section 1101 for scanning the original image and inputting the RGB signals, the selector 1102 controlled by the control signal 1120, and the similar control. A selector 1107 controlled by a signal 1121, a printer 1108 that outputs an image, a CPU 1105, an image signal that represents a patch, and a memory 1 that stores values of six primary colors that represent a color reproduction range.
106, a matrix conversion circuit 1103 for performing color processing,
A color processing circuit 1104, a sampling circuit 1109 used when determining the color reproduction range of the printer 1108,
Buffer memory 1110, pattern generation circuit 1111
It is composed of.

(Normal Image Processing) The case of performing normal output will be described. The RGB signal input by the input unit 1101 is input to the matrix conversion circuit 1103 through the selector 1102 based on the control signal 1120 from the CPU 1105. Specifically, the matrix conversion circuit 1103 performs the following matrix calculation on the input RGB signals using the coefficients set by the CPU 1105, and outputs R ′, G ′, B ′.

[0122]

[Outside 2]

Here, R, G and B are the original R, G and
In the B signal, dR, dG, and dB are image signal compression amounts obtained by the following calculation.

[0124]

[Outside 3]

Here, X represents the minimum value of R, G, and B.

Next, how to obtain the matrix conversion coefficient aij of the equation (3) set by the CPU will be described. The purpose of the matrix conversion is to map the colors of the original document having a wide color reproduction range to the color reproduction range of the printer, that is, to compress the color space, as shown in FIG. Here, reproduction of red will be described first.

Assuming that the image signal is represented by R, G, and B for each 8 bits, the most saturated red color of the document (for example, indicated by the RG point in FIG. 23) is R = 200, G = 15, B =
It is assumed that the color signal is 0. However, the most saturated red color that can be reproduced by the printer is the RP point, so RP
All the colors between the points and the RG points will be printed out as the colors of the RP points.

On the contrary, when the color signal value at the RP point is represented by R, G, B signals, it is usually about R = 160, G = 20, B = 10. Therefore, the input color signal is R = 200, G
= 15 and B = 0 by the matrix conversion circuit R ′ =
By converting so that 160, G ′ = 20, B ′ = 10, the RG point is converted to the RP point, the colors in between are mapped to the inside of the RP point, and the primary colors of the input signal are preserved, The color gamut of the original image can be mapped to the color gamut of the printer.

In addition, such a correspondence relationship is obtained by setting the six primary colors (R,
If all G, B, C, M, and Y) are set, 18 simultaneous equations can be created from the equations (2) and (3). Since there are still 18 matrix conversion coefficients aij of equation (3) as unknowns, they can be uniquely solved.

Next, the matrix conversion circuit 10 described above.
Image signals R ', G'compressed by 3
In B ′, color processing such as logarithmic conversion, masking, and UCR (undercolor removal) is performed in the color processing circuit 1104, and C, M, Y, and K are used.
Is converted to. Then, based on a control signal 1121 from the CPU 1105, the selector 1107 inputs it to the printer 1108, and an image is formed based on the image signal input by the printer 1108.

Therefore, since the input image signal is converted into the color reproduction range of the printer 1108 while preserving the gradation, the gradation is preserved even for the pixels outside the color reproduction range of the printer 1108, and the original is more faithful to the original. Images can be output.

The color reproduction range is set to R, G, B, C, M,
The color reproduction range can be easily updated by defining with 6 points of Y.

(Color Reproduction Range Judgment Process of Printer) Six primary colors R, G, which correspond to the outermost part of the color reproduction range of the printer,
The values of C, M, Y, and K representing B, C, M, and Y are set in the memory 1106 in advance, and the set values are developed into an image signal by the pattern generation circuit 1202 via the CPU 1105.
Output to the printer 1108 through the selector 1203, and the printer 1108 outputs the six primary colors R, G, B, C, M,
A patch indicating Y is output. The output patch is read by the input unit 1101 and input to the sampling circuit 1109 through the selector 1102.

In the sampling circuit 1109, a signal corresponding to a predetermined position of a patch which is an original image is sampled at a predetermined sampling pitch, and the buffer memory 11
Write to 10. CPU 1105 is buffer memory 1
Image signals in 110 are sequentially read, each average value of each output patch is calculated, the outermost set value of the color reproduction area of the printer is determined, and the set value is set in the memory 1106.

Therefore, for example, even if there is unevenness in the output patch, since it is obtained by averaging the sampled values, the error from the original value is reduced, and a more accurate color reproduction range can be obtained.

An example of the C, M, Y, K values of the output signal values of the patch indicating the six primary colors preset in the memory 1106 for determining the outermost color reproduction range of the printer and read by the reading device. The correspondence between the R, G, and B signal values is shown. The R, G, and B signal values shown in FIG. 23 when mapping the outermost six primary colors of the original document to the color gamut of the printer
It corresponds to P, GP, BP, CP, MP, YP.

[0137]

[Outside 4]

FIG. 22 shows patches output by the printer based on the above-mentioned 6 primary colors. The patches 402 to 407 of the six primary colors (R, G, B, C, M, and Y) are output on the output paper 401 at predetermined positions at predetermined positions with predetermined signal values. Reference numeral 408 is a positioning mark.

Next, the flow of processing for determining the color reproduction range of the printer will be described with reference to the flowchart of FIG.

In step 301, the C, M, Y, and K values of the six primary colors as shown in equation (4) are set in advance in the memory 1106 as the output patch values. Step 1302
Pattern generation circuit 1111 based on the value set in
2 to develop an image signal, and the printer 1108 displays the image signal as shown in
The patch as shown in 2 is output. Step 1303
The patch output in step 1408 is set at a predetermined position on the document table of the input unit 1101 based on the positioning mark 1408.
In step 1304, the patch on the platen is read by the input unit 1101. Buffer memory 1 in step 1305
The input RGB signals stored in 110 are sampled by the CPU 1105 and the printer 1 calculates the calculated values.
The outermost of the color reproduction range of 108 is determined, and the memory 110
The outermost 6 primary color values are set to 6.

As described above, the printer 1108 has been described.
When the color reproduction range of 6 is approximately represented by 6 primary colors, the outermost part of the color reproduction range can be easily determined by outputting the 6 primary colors with the highest density value that the printer 1108 can output. be able to.

Further, even if the color reproduction range varies from machine to machine due to machine differences, installation environment differences, and changes over time, it is possible to set an accurate color reproduction range according to the engine state and ink state of the printer 1108. it can.

Therefore, the color gamut that can be actually expressed can be effectively used, and the color space compression processing such as the above-mentioned matrix conversion can be effectively used.

In the printer color reproduction determination process described above, if the image processing apparatus has a calibration function for correcting and stabilizing the recording unit, the color reproduction is performed after the calibration is performed to correct the recording unit. A determination process is performed, and a portion that could not be corrected by calibration is recognized by the color reproduction determination process to correct the image processing.

Therefore, even when the calibration function cannot cope with the change in the color reproduction range caused by the installation environment or the change with time, the image processing can be accurately corrected by performing the color reproduction determination processing. Further, as shown in the fourth embodiment, the determined color reproduction range may be notified to the user.

(Modification 1 of Sixth Embodiment) Second Embodiment of the Present Invention
A modified version of the patch of the first embodiment will be described with reference to the drawings.

In the present embodiment, in order to detect the color reproduction range of the printer with higher accuracy, a plurality of patches are output for each of the six primary colors as shown in FIG. Detect and set the color gamut of the printer.

FIG. 25 shows a flowchart of the processing flow.

For example, FIG. 24 shows a case where four primary colors are output for each four. Here, the number is four for simplification of description, but the present invention is not limited to this, and needless to say, the accuracy increases as the number increases.

First, in step 1701, the C, M, Y, and K values of each patch in FIG. 6 are set in advance. Step 17
In 02, the patch is output from the image output device with the set value. The patch output in step 1703 is installed in the image reading device. In step 1704, the R, G, B signal values are read. Of the four patches of each primary color read in step 1705, the outermost patch is detected by the method described later.
The R, G, B signal values of the patch detected in step 1706 are determined as the outermost part of the color reproduction range.

Next, a method of detecting the outermost patch of the patches of each primary color will be described with reference to FIG.

First, in order to detect in the uniform color space, in step 801, the R, G, B signals of each primary color are converted into L ^* , u ^* , v ^* . The following formulas may be used to convert R, G, B into L ^* , u ^* , v ^* .

L ^* = 116 (Y / Y0) ¹ / 3-16 u ^* = 13L ^* (u-u0) v ^* = 13L ^* (v-v0) where u = 4X / (X + 15Y + 3Z) v = 9Y / (X-15Y + 3Z) Also, X = 0.6067R + 0.1736G + 0.20
01B Y = 0.2988R-0.5868G + 0.1144B Z = 0.0000R-0.0661G + 1.1150B Here, in order to simplify the description, the description will be given in red, and L ^* , u ^* , v ^{* of} four patches will be described ^. The values are shown in FIG.

As shown here, the larger the distance from the center point O, the more outside the color reproduction range, so the distance d from the center point is obtained in step 802.

D = L ^{* 2} + u ^{* 2} + v ^{* 2} (5) Further, the following formula may be used to simplify the calculation.

D = u ^{* 2} + v ^{* 2} (6) In step 803, the maximum value of d is obtained.

In FIG. 27, it can be seen that dR3 is the maximum and R3 is the point where the saturation of red is maximum.

Therefore, in step 1804, the read R, G, and B signals of R3 are set as the outermost part of the red color gamut. The other five colors are obtained in the same manner as R, and the maximum value of the color reproduction range of the six primary colors is obtained.

The L ^* , u ^* , and v ^* spaces are used to detect the outermost part of the color space, but this is an example, and L ^* , a ^* , b ^* , Y, and I of other color spaces are used. , Q, etc. may be used.

Therefore, even if the outermost part of the color reproduction range is slightly shifted in luminance, hue, and saturation, a plurality of patches are used so that it can be dealt with, and the outermost part of the color reproduction range can be accurately grasped.

(Modification 2 of Sixth Embodiment) The above embodiment (6)
In the embodiment using the primary colors, the six primary colors of R, G, B, C, M, and Y have been described, but as in the fourth embodiment, white (W) and black (Bk) are added to make the eight primary colors. May be expanded.

The case of using the eight primary colors will be described below.

First, black will be described. The maximum black reproduction range corresponds to the maximum density of black. An example of the output signal value of the black patch for determining the outermost part of the reproduction range of the printer and the R, G, B signal values read by the reading device is shown below. Shown in.

C = 145, M = 145, Y = 145, K
= 255 → R = 4, G = 4, B = 4 Since the maximum density patch of black is 4 in the read value, it will not be reproduced when the value is 4 or less. However, according to the method described for the six primary colors, the equation (7) is transformed so that even if the black minimum read value of the original is the outermost one such as 1, 1 is converted to 4.
By using, it is possible to reproduce gradations of 4 or less.

Next, in the case of white, since the white portion where nothing is printed becomes the maximum white, the output values C, M, Y, K of the printer must be zero. The output values C, M, Y, K of the printer become 0 when the R, G, B signal values of the read value are 255 (maximum read signal value), so it is necessary to forcibly set the value to 255. .

However, the printer output values C, M, Y,
If K is 0 and nothing is actually output, output a white patch (printer output values C, M, Y, K = 0) and compare it with the background value of the paper other than the read patch by the reading device. Make sure the printer is not covered and is working properly.

An example of a patch for determining the outermost part of the reproduction range of the printer when the above white and black are added is shown in FIG.
Shown in.

[0168]

[Outside 5]

Here, R, G and B are the original R, G and
In the B signal, dR, dG, and dB are image signal compression amounts.

(Seventh Embodiment) This embodiment corresponds to the fact that the color reproduction range differs depending on each processing mode.

Now, the seventh embodiment of the present invention will be described in detail with reference to FIG.

In FIG. 28, the same components as those in the sixth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 28, the controller 1112 has four
An instruction to set either the color mode or the three-color mode is output to the CPU 1105. The color processing circuit 1130 receives R ′, G ′, input from the matrix conversion circuit 1103,
By switching the selector 1141 based on the control signal 1122 from the CPU 1105, the B ′ signal is changed to 4
Color processing such as masking processing is performed in the color mode 1142 or the three-color mode 1143. Here, in the four-color mode, the input R ', G', B'signals are C, M, Y,
This is a mode for converting into K signals, and the three-color mode is a mode in which inputted R ', G', B'signals are converted into C, M, Y signals. In normal image processing, this color processing circuit 1
An image is formed by the printer 1108 based on the C, M, Y, and K color signals (four-color mode) or the C, M, and Y color signals (three-color mode) output from the printer 130.

The controller 1112 issues an instruction to set either the four-color mode or the three-color mode to the CPU 1105.
Output to.

Since the number of inks used is different between the 4-color mode and the 3-color mode, the color reproduction range of the printer 1108 also differs.

Therefore, the image data for outputting the patches for the four-color mode and the patch for the three-color mode are stored in the memory 1106 in advance, and the image data for outputting the patch by the pattern generating circuit for each mode. Convert to. That is, the C, M, Y, and K signals are output for the four-color mode and the C, M, and Y signals for the three-color mode, and the patch is printed by the printer 1108 as in the above-described embodiment. Is output and is read by the input unit 1101 to determine the outermost part of the color reproduction range, and is stored in the memory 1106 in association with each mode.

In normal image processing, image processing is performed using the color reproduction range stored in the memory 1106 corresponding to the set mode.

Therefore, not only the difference in the color reproduction range for each machine but also the difference in the color reproduction range depending on the set mode such as the number of inks to be used is taken into consideration. It can be used and color space compression such as matrix conversion can be effectively utilized.

Therefore, the features of each mode can be maximized, and the user can obtain a desired image.

The present invention is not limited to the four-color mode or the three-color mode. For example, when the UCR amount is changed, when the printing method is changed, or when a recording material such as OHP or coated paper is set, output is performed. For each mode in which the color reproduction range that can be reproduced by the device changes, data indicating the color reproduction range may be stored in each mode.

It is also possible to divide the modes into groups without corresponding to all the modes and hold the data indicating the color reproduction range for each group.

Further, as shown in the fourth embodiment, the color reproduction range corresponding to each mode may be displayed.

(Eighth Embodiment) With reference to FIG. 29, an eighth embodiment of the present invention will be described in detail below as an example of applying the above embodiment to a system constituted by a plurality of devices.

In FIG. 29, the image output device 1160 is, for example, an LBP, an inkjet, an IPU and a CLC, or the like, and in the case of the IPU and the CLC, it has the structure described in the above-mentioned embodiment. The host 1150 performs image processing such as image editing, color conversion and color correction, and outputs the image to the image output device 1160 to form an image.

Therefore, when performing image processing in the host 1150, it is necessary to consider the color reproduction range of the image output device 1160 and perform image processing. Therefore, the host 1150
Holds the color reproduction range of the image processing apparatus 1160 in advance.

When the data indicating the color reproduction range of the image output device 1160 is updated as in the above embodiment,
Data indicating the color reproduction range is transferred from the memory 1106 to the controller 1112 via the CPU 1105, and transmitted from the controller 1112 to the host 1150 which is an external device. Then, the host 1150 updates the data indicating the color reproduction range in the profile for the corresponding output device, that is, the image output device 1160 in FIG. 29, based on the received data.

The image output device 1150 to the host 1
The timing of transfer to 160 is, for example, the image output device 150.
When the data showing the color reproduction range is updated with
It is when the transfer request is issued from 60.

Therefore, since the profile relating to the color reproduction range of the image output device 1160 in the host 1150 can be always held with correct information, the host 115
The image processing result of 0 is the one that makes the most effective use of the color reproduction range.

Also, the updated data is the image output device 1
Since it is transferred from 160, it is not necessary for the user to rewrite the profile of the host 1150 using an input device such as a keyboard, so that the update can be performed by a simple operation.

A system in which a host and an image output device are combined is described as an example applied to a system composed of a plurality of devices, but the present invention is not limited to this, and, for example, a host includes a plurality of input devices and It may be applied to a system or the like in which image output devices are combined.

Further, according to the present invention, the image processing using the color reproduction range is not limited to the matrix conversion circuit, and, for example, a process of creating an LUT using the color reproduction range and performing color space compression or input image data is color-coded. It may be a process of determining whether or not it is within the reproduction range.

Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

Further, the image processing apparatus is not limited to the above-mentioned one, and a head of a type that causes film boiling due to thermal energy to eject droplets and a recording method using the same may be used.

As described above, according to the present invention, since the color space compression is performed using the color reproduction range determined based on the output patch, the color space compression is performed by effectively using the expressible color reproduction range. Therefore, it is possible to obtain a high quality image.

Further, according to the present invention, since the data showing the color reproduction range can be updated based on the output image, it is possible to deal with the mechanical difference, the installation environment, the change with time and the like and to express it. The color reproduction range can be effectively used.

Further, according to the present invention, the patch showing the outermost portion of the color reproduction range is determined from a plurality of patches, so that the color reproduction range can be accurately determined.

Further, according to the present invention, since the data showing the color reproduction range corresponding to each of the color processing means is held, the expressible color reproduction range can be effectively used.

Further, according to the present invention, since the data indicating the determined color reproduction range is transferred to the external device, the external device accurately determines the color reproduction range corresponding to the mechanical difference of the output means, the installation environment, and the change over time. Can be grasped.

(Ninth Embodiment) As the eighth embodiment of the present invention, a series of processing using the processing described in the above embodiment will be described below with reference to FIG.

A series of processes is roughly classified into two processes, a color reproduction range changing process and a normal print process using a set color reproduction range.

First, the color reproduction range changing process will be described. In step S2001, the color reproduction range of the target device is determined, that is, the series of processes shown in FIG. 7, for example, is performed. Specifically, a patch corresponding to 6 primary colors or 8 primary colors is output depending on the target device, and the color reproduction range is determined based on the data read at the input stage. When this determination processing is performed by the host computer 301 in the system shown in FIG. 10, the user sets each condition based on the screens shown in FIGS. 8A and 8B, for example. Each condition is, for example, a target device, designation of a scanner for reading an output patch, setting of a processing mode, or the like.

In step S2100, the color reproduction range determined in step S2001 is graphically displayed as a three-dimensional solid on the monitor. In this way, by actually displaying a graphic, the state relating to the color reproduction range of the target device can be easily recognized.

Therefore, when the color reproduction range of the target device is narrowed due to various causes such as aging, repair can be taken.

In step S2200, the data indicating the color reproduction range obtained in step S2001 is updated in correspondence with the target device name, stored in the memory on the host, and managed.

It is also possible to newly associate the device name with the color reproduction range and save it as a profile.

Therefore, it is possible to cope with the change of the color reproduction range due to the change of each device with time and the difference of environment. Furthermore, when the system in which each device is connected to the bus as shown in FIG. Therefore, it is possible to flexibly deal with the devices that make up the system.

Next, the normal print processing will be described.

In step S2300, image data representing a document is input and stored in the image memory 101.

Initial conditions are set in S2400. The initial conditions specifically include designation of an output device, whether or not to perform color space compression, and designation of a processing mode (3 color mode, 4 color mode, etc.)
Etc.

In S2500, it is determined whether the image data obtained in S2300 is within the color reproduction range indicated by the color reproduction range data read from the memory based on the setting conditions in S2400.

Note that the determination result may be displayed on the monitor here. Further, the user can reset the initial condition based on the display result, and the user can select the optimum process by repeating these processes.

In step S2600, the color space compression processing shown in, for example, the fifth embodiment is performed on the input image data.

S2700 outputs based on the image data obtained by the above processing.

By the above series of processing, the user can easily select and execute the optimum processing.

The present invention is not limited to storage in the memory on the host, and for example, a profile corresponding to each device of the output device is stored, and according to the protocol with the host,
It may be transferred to the host side when necessary.

The present invention is not limited to the above embodiments, but can be variously modified within the range of frames.

[0217]

As described above, according to the first aspect of the present invention, the color reproduction range of the output device can be obtained with a small storage capacity.

Further, according to the second invention of the present application, it is possible to determine whether or not the color signal of the image is included in the reproduction range by a simple process.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of color reproduction range determination processing in a color conversion apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a uniform color space for explaining a color reproduction range.

FIG. 3 is a schematic diagram of a uniform color space for explaining a plane for determining a color reproduction range.

FIG. 4 is a schematic diagram for explaining a determination method based on a plane.

FIG. 5 is a schematic diagram for explaining a determination method according to another embodiment.

FIG. 6 is a schematic diagram for explaining correction of an image signal outside the color reproduction range according to still another embodiment.

FIG. 7 is a diagram illustrating an example of a processing procedure related to printer calibration processing.

FIG. 8 is a diagram showing an example of a screen display during printer calibration processing.

FIG. 9 is a diagram showing an example of a pattern that is output by an output device during printer calibration processing.

FIG. 10 is a diagram showing an example when the system is assembled.

FIG. 11 is a conceptual diagram of the fifth embodiment.

FIG. 12 is a flowchart showing the flow of processing of a fifth embodiment.

FIG. 13 is an explanatory diagram of a device color reproduction area according to the fifth embodiment.

FIG. 14 is an explanatory diagram of a relative distance according to the fifth embodiment.

FIG. 15 is a diagram showing a graph showing a relationship between a pixel ratio and a coefficient α.

FIG. 16 is a block diagram showing the configuration of an image processing circuit according to a modification of the fifth embodiment.

17 is a block diagram showing a configuration of a mapping control circuit 6 shown in FIG.

18 is a block diagram showing a configuration of a mapping circuit 5 shown in FIG.

FIG. 19 is a block diagram showing the configuration of an image processing circuit according to a modification of the fifth embodiment.

FIG. 20 is a block diagram showing an embodiment of an image processing apparatus of the present invention.

FIG. 21 is a flowchart showing an example of image processing of the present invention.

FIG. 22 is a diagram showing an example of an output patch used in the sixth embodiment of the present invention.

FIG. 23 is a diagram illustrating an example of a difference in color reproduction range between a printer and a document.

FIG. 24 is a diagram showing an example of an output patch used in modification 1 of the sixth embodiment of the present invention.

FIG. 25 is a flowchart showing an example of image processing of Modification 1 of the sixth embodiment of the present invention.

FIG. 26 is a flowchart showing an example of image processing for detecting the outermost part of the color reproduction range.

FIG. 27 is a diagram illustrating an example of a method for detecting the outermost portion of a color reproduction range.

FIG. 28 is a block diagram showing a modified example of the image processing apparatus of the present invention.

FIG. 29 is a block diagram showing an example of systemization of the present invention.

FIG. 30 is a diagram showing an example of an output patch used in modification 2 of the sixth embodiment of the present invention.

FIG. 31 is a flowchart showing an example of the flow of a series of processing according to the present invention.

[Explanation of symbols]

 101 image memory 102, 105 uniform color space conversion unit 103 8 primary color measurement value table 104 output device designation unit 106 plane definition unit 107 color reproduction range determination unit 108 determination flag

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Claims (18)

[Claims] 1. A generation means for generating a plurality of color image data corresponding to a color saturation that is substantially limitable for output in an output device and having different hues, and based on the plurality of color image data. A color image processing device, comprising: an interpolation generating unit that interpolates and generates a boundary surface of a reproduction range that can be output by the output device. 2. The plurality of color image data having different hues from each other are the primary color of a recording material indicating the color of the output device,
The color image processing apparatus according to claim 1, which is compatible with a secondary color. 3. The image according to claim 1, wherein the plurality of color image data having different hues are color image data of each color of Y, M, C, B, G, R, K and W. Processing equipment. 4. A determination means for determining whether or not the input image data is within the reproduction range based on the boundary surface of the reproduction range interpolated and generated by the interpolation generation means. The described color image processing device. 5. A color image processing device for converting a color image signal into output data of an output device for visualizing output, wherein primary color data and the color image signal defined based on colors that can be output by the output device. A conversion unit that converts the data into data belonging to the same color space, a plane in the color space defined by the values of the converted primary color data, and a color image signal after the conversion. A color image processing apparatus comprising: a determining unit that determines whether or not the color indicated by the color image signal can be output by the output device according to a positional relationship with the value. 6. The color image processing apparatus according to claim 5, wherein the primary color data is colorimetric value data. 7. The color image processing device has the primary color data for each of a plurality of different output devices, and the primary color data corresponding to the output device designated by the output device designating means is converted by the converting means. The color image processing apparatus according to claim 5, wherein 8. The plane is a plane including a triangle defined by three values selected by a predetermined combination of a plurality of the converted values of a plurality of the primary color data,
The color image processing apparatus according to claim 5, wherein 12 combinations are predetermined as the predetermined combination. 9. The determining means determines whether one point on a predetermined axis of the color space determined in advance and the converted value of the color image signal are on the same side across the plane. The color image processing apparatus according to claim 5, wherein the determination is performed depending on whether or not the color image processing apparatus is a color image processing apparatus. 10. The determining means converts the color image signal into a tetrahedron formed by the three coordinate values and one point on the predetermined axis of the color space determined in advance. 10. The color image processing apparatus according to claim 9, wherein the determination is made based on whether or not a value included in the color image is included. 11. The color image processing apparatus according to claim 5, wherein the output device uses a head of a type that ejects droplets even when film boiling occurs due to thermal energy. 12. A color signal processing device for converting a color image signal into output data of an output device for visualizing output, and storage means for storing primary color data determined based on colors that can be output by the output device. A conversion unit that converts the primary color data and the color image signal into a value in the same color space; a plane defined by the changed value of the primary color data in the color space; A color image processing device, comprising: a determination unit that determines whether or not the color indicated by the color image signal is a color that can be output by the output device, according to a positional relationship with the value of the color image signal. 13. Further, based on the result of the judging means,
13. The color image processing apparatus according to claim 12, further comprising a correction unit that corrects the color image signal into an outputable image signal. 14. The determining means determines whether the color indicated by the color image signal is a color that can be output by the output device, based on a convergence point inside the solid obtained by the primary color data. 13. The color image processing apparatus according to claim 12, wherein 15. Color image data corresponding to a saturation that can be output from an output device, wherein a plurality of color image data having different hues are generated, and the generated plurality of color image data having different hues are generated. From the above, a color image processing method comprising interpolating and generating a boundary surface of a reproduction range that can be output from the output device. 16. The color image data according to claim 1, wherein the plurality of color image data having different hues are color image data of Y, M, C, B, G, R, K and W colors. Color image processing method. 17. A color image processing method for converting a color image signal into output data of an output device for visualizing output, wherein primary color data and the color image signal defined based on colors that can be output by the output device. A conversion step of converting to data belonging to the same color space, a plane in the color space defined by the value of the converted primary color data, and a conversion of the color image signal after the conversion. A color image processing method for determining whether or not the color indicated by the color image signal is a color that can be output by the output device according to a positional relationship with a value. 18. A color signal processing device for converting a color image signal into output data of an output device for visualizing output, and a storage step of storing primary color data determined based on colors that can be output by the output device. A conversion step of converting the primary color data and the color image signal into a value in the same color space; a plane defined by the changed value of the primary color data in the color space; A color image processing device, comprising: determining whether or not the color indicated by the color image signal is a color that can be output by the output device according to a positional relationship with the value of the color image signal.