JPH07222015A - Color image processor - Google Patents

Abstract

PURPOSE:To simply decide whether or not inputted color image information is within a color reproduction range of a color image output device by providing a virtual device means implementing processing reverse to that of the color image output device. CONSTITUTION:A virtual image output device VP is built in the image processing unit 107. The virtual image output device VP is composed of a neural network using a back propagation. A parameter in which an input to the neural network is cmy and an output from the neural network is L*a*b* is called a forward VP and a parameter when the input and output are reversed is called a reverse VP. Picture information (RGB data) is converted into three- stimulus values XYZ and the XYZ is converted into the signal L*a*b*. Then the cmy is calculated by the virtual image output device VP in the reverse VP. Whether or not all the calculated cmy is within an actual measurement density range of the image output device 102 is decided. When within the range, it is decided that the image information is within the color reproduction range of the image output device 102.

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 for subjecting input color image information to color correction processing for correcting color image information within a color reproduction range of a color image output apparatus.

[0002]

2. Description of the Related Art Conventionally, color correction for correcting color image information input from a color image input device such as a scanner or a computer into color image information within a color reproduction range of a color image output device such as a printer or display. In the color image processing device for processing, when the color image information at a position exceeding the color reproduction range of the color image output device is input, the position within the space of the color reproduction range closest to the position of the color image information is detected. And a method of compressing (reducing) the input color image information toward the center of gravity of the space of the color reproduction range and outputting.

Further, in this case, the determination of the color reproduction range has information (a model obtained by dividing a three-dimensional space for color reproduction) which models the color reproduction range of the color image output device, and the color image input with this model. The judgment was made by comparing with the information.

On the other hand, regarding the compression processing and the color correction, the user actually judges whether the image is good or bad by actually outputting the corrected image by the color image output device, and re-processes it.

[0005]

However, according to the above-mentioned conventional technique, the determination is made by comparing the color reproduction range modeling information of the color image output device with the input color image information. However, there is a problem in that it is necessary to appropriately create information that models the color reproduction range according to each color image output device, and the construction of the determination process is troublesome. In particular, in the case of a system in which the color image output device connected to the color image processing device can be easily replaced, the setting of various parameters used in the determination process needs to be changed each time, which is troublesome. .

Further, according to the above-mentioned conventional technique, since the determination process is performed on all the pixels forming the color image information, there is a problem that the process takes time.

Further, in the method of compressing the input color image information toward the center of gravity of the color reproduction range space in the above-mentioned conventional technique, when the input color image information is almost included in the color reproduction range space, , The problem that a small image is output as a whole because the color image information in the color reproduction range space is converted to the achromatic direction by being affected by a small number of pixel data outside the color reproduction range, When the image information is compressed, there is a problem that the color tone is lost as a whole.

Further, according to the above-mentioned conventional technique, in the method of compressing toward the center of gravity of the color reproduction range space, the compression rate is automatically determined, so that it is not always possible to obtain a color image desired by the user. There was a problem.

Further, according to the above-mentioned conventional technique, when the connected color image input device or the color image output device is replaced, or when the connected color image output device changes with time or changes in the environment. On the other hand, there was a problem that it was not possible to respond promptly.

The present invention has been made in view of the above, and it is easy to construct a parameter used when it is determined whether the input color image information is within the color reproduction range of the color image output device. The first purpose is to enable the determination process as well as to enable the determination process.

Further, the present invention has been made in view of the above, and aims at speeding up the determination processing, and a color image is affected by a small number of pixel data out of the color reproduction range, so that the overall tint is improved. The second purpose is to be able to avoid losing.

The present invention has been made in view of the above, and it is a third object of the present invention to prevent loss of color tone as a whole when a color image is compressed.
The purpose of.

The present invention has been made in view of the above, and it is a fourth object of the present invention to enable the user to set an allowable compression ratio and obtain a color image desired by the user. To do.

The present invention has been made in view of the above, and when the connected color image input device or color image output device is replaced, or when the connected color image output device is aged. The fifth objective is to be able to quickly respond to changes and environmental changes.

[0015]

In order to achieve the above object, a color image processing apparatus according to a first aspect of the present invention provides a color image within a color reproduction range of a color image output apparatus with respect to input color image information. In a color image processing device for performing color correction processing for correcting information, the color image output device in the color image output device corresponds to input color image information, and the input color image information corresponds to output color image information. Virtual device means for performing processing in the opposite direction to the output device, and whether or not the input color image information is within the color reproduction range of the color image output device based on the output color image information of the virtual device means. And a determination means for performing determination.

A color image processing apparatus according to a second aspect of the present invention is a color image processing apparatus for performing color correction processing for correcting input color image information to color image information within a color reproduction range of a color image output apparatus. In the above, the uniform color space is divided into a plurality of areas, and the image information representative means for representing the inputted color image information existing in each area by one representative information for each area, and the image information representative means existing in each area for each area. The pixel number counting means for counting the number of pixels of the input color image information, the determining means for determining whether or not the representative information is within the color reproduction range of the color image output device, and the determining means. Ratio calculating means for calculating the ratio of the total number of pixels corresponding to the representative information determined not to be within the color reproduction range and the total number of pixels of the input color image information, and the ratio calculated by the ratio calculating means But when it exceeds a predetermined value, in which a linear compression means for performing a linear compression with respect to the color image information the input.

Further, in the color image processing apparatus according to the third aspect, the linear compression means can change the compression rate for each area.

A color image processing apparatus according to a fourth aspect is a color image processing apparatus for performing color correction processing for correcting input color image information to color image information within a color reproduction range of a color image output apparatus. In the above, the uniform color space is divided into a plurality of areas, and the image information representative means for representing the inputted color image information existing in each area by one representative information for each area, and the image information representative means existing in each area for each area. The pixel number counting means for counting the number of pixels of the input color image information, the determining means for determining whether or not the representative information is within the color reproduction range of the color image output device, and the determining means. Ratio calculating means for calculating the ratio of the total number of pixels corresponding to the representative information determined not to be within the color reproduction range and the total number of pixels of the input color image information, and the ratio calculated by the ratio calculating means When the value exceeds a predetermined value, the compression rate determining means for determining the compression rate by a preset calculation, the compression rate setting means for the user to set the compression rate, and the compression rate setting means are used. When the compression rate is set by the linear compression, the input color image information is linearly compressed using the compression rate. In other cases, based on the compression rate determined by the compression rate determining means, And a linear compression unit that performs linear compression on the input color image information.

Further, in the color image processing apparatus according to the fifth aspect, the compression rate determining means calculates the compression rate for each of the areas.

A color image processing apparatus according to a sixth aspect of the present invention is a color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of a color image output apparatus. In the virtual image output device, the output color image information corresponds to the input color image information, and the input color image information corresponds to the output color image information. Determining means for determining whether the input color image information is within a color reproduction range of the color image output device based on the output color image information of the virtual device means; Measuring means for measuring changes with time and environmental changes, wherein the virtual device means is based on the measurement result of the measuring means, and the color From among the plurality of parameters set in consideration of the aging and environmental change of an image output apparatus, by selecting an optimal parametrize, and performs processing of the reverse.

A color image processing apparatus according to a seventh aspect of the present invention is a color image processing apparatus for performing color correction processing for correcting input color image information to color image information within a color reproduction range of a color image output apparatus. In the virtual image output device, the output color image information corresponds to the input color image information, and the input color image information corresponds to the output color image information. Determining means for determining whether the input color image information is within a color reproduction range of the color image output device based on the output color image information of the virtual device means; The output color image information obtained by the processing in the opposite direction is based on the measuring means for measuring the change over time and the environmental change and the measurement result of the measuring means. It is obtained by a correction means for correct output.

[0022]

In order to achieve the above object, the color image processing apparatus according to the present invention (claim 1) performs the processing in the opposite direction to the color image output apparatus by the virtual device means, and the virtual device means by the judging means. It is determined whether the input color image information is within the color reproduction range of the color image output device based on the output color image information of.

Further, the color image processing apparatus according to the present invention (claim 2) divides the uniform color space into a plurality of areas, and the input color image information existing in each area is represented by one piece of representative information. Representative information (representative points of the image)
Uses to speed up the calculation. Further, the number of pixels of the input color image information existing in the area is counted for each area, and it is determined whether the representative information is within the color reproduction range of the color image output device to determine the color. Obtain the ratio of the total number of pixels corresponding to the representative information determined not to be within the reproduction range and the total number of pixels of the input color image information,
When the calculated ratio exceeds a predetermined value (threshold value), the input color image information is linearly compressed.

Further, in the color image processing apparatus according to the present invention (claim 3), the compression rate can be changed for each area in the linear compression means, so that the compression rate is increased as the data is farther from the compression reference point. This reduces the loss of color when the image is compressed.

Further, in the color image processing apparatus according to the present invention (claim 4), when the user sets the compression rate through the compression rate setting means, the color image processing apparatus uses the compression rate to linearly input color image information. The compression is performed. In other cases, based on the compression rate determined by the compression rate determining means, linear compression is performed on the input color image information, so that the image is compressed at a compression rate of a value that the user can tolerate. Perform compression.

In the color image processing apparatus according to the present invention (claim 5), the compression rate determining means calculates the compression rate for each area to increase the compression rate for data farther from the compression reference point. ， Reduces the loss of color when the image is compressed.

Further, the color image processing apparatus according to the present invention (claim 6) measures the temporal change / environmental change of the color image output apparatus, and based on the measurement result, the temporal change / environment of the color image output apparatus in advance. An optimum parameter is selected from a plurality of parameters set in consideration of fluctuations, the virtual device means performs processing in the opposite direction to the color image output device, and the determination means outputs the color image output from the virtual device means. Based on the information, it is determined whether the input color image information is within the color reproduction range of the color image output device.

Further, the color image processing apparatus according to the present invention (claim 7) performs processing in the opposite direction to the color image output apparatus by the virtual device means. In addition, the time-dependent changes and environmental changes of the color image output device were measured, and based on the measurement results,
Whether the input color image information is within the color reproduction range of the color image output device on the basis of the corrected output color image information by the determination means by correcting the output color image information obtained by the reverse processing Determine whether or not.

[0029]

[Examples] [Examples 1], [Examples 2], [Examples 3], [Examples 4], and 4), in which the color image processing apparatus of the present invention is applied to a color digital multi-function peripheral as an example.
[Embodiment 5] and [Embodiment 6] will be described in detail with reference to the drawings.

[Embodiment 1] FIG. 1 is a system block diagram of a color digital multi-function peripheral equipped with a color image processing apparatus of the present invention. A color digital multi-function peripheral means a system equipped with a conventional digital color copying machine, such as a color facsimile or a mass storage device, with a communication function. Here, the outline of the system of FIG. 1 will be described.
An image reading device 101 for reading an image as digital data, such as a scanner, and an image output for forming an image on a recording sheet such as a paper or an OHP sheet, such as a printer, are provided on a system bus 100 for passing control signals and image data A device 102, an image display device 103 such as a monitor for displaying / confirming an image, a storage device 104 such as a hard disk or a magneto-optical disk, an operation / input device 105 for inputting and displaying processing instructions / settings to the device, A control device 106 that controls each device, an image processing device (color image processing device of the present invention) 107 that processes and edits digital image data, and a communication device 108 that is responsible for connection with a communication network such as encoding and decoding. An external I / F (interface) 109 for connecting an external device such as a computer is connected.

In the above configuration, the relationship between the target image information and the color reproduction range of the image output apparatus 102 will be described in the order of the inside / outside determination processing of the built-in color reproduction range of the virtual device (VD) in the image processing apparatus 107. .

Relationship between Target Image Information and Color Reproduction Range of Image Output Device 102 When the image processing device 107 performs image processing, the target image information (input color image information) is created on the image display device 103. Image information (for example, computer graphics image information) and the image reading device 101
Image information (eg, R / G / B data for normal color copying, negative data, etc.) read by

In general, the image information created on the image display device 103 includes high-luminance and high-saturation colors which are not found in photographs or printed materials because of the wide color reproduction range of the image display device 103 itself. Often. Therefore, the image output device 1
Since there is a large amount of image information that exceeds the color reproduction capability that can be output by 02, when the target is image information created on the image display device 103, image processing that matches it is required.

Therefore, since the maximum color reproduction capability of the image output device 102 in the system of FIG. 1 is fixed, when outputting by the image output device 102, the color reproduction range of the target image information and the image output device 102. It is necessary to make a comparison with the color reproduction range of. That is, the inside / outside determination is necessary to know how much the target image information is included in the color reproduction range of the image output device 102.

2A to 2D show the image output device 10
2 shows the relationship between the color reproduction range of 2 and the target image information. Displaying the color space of the target image information in the uniform color space (the color spaces are aggregated into one space) can be roughly classified as follows. In the figure, 200 indicates the color reproduction range of the image output device 102 in the uniform color space CIELAB, and 201 indicates the color space of the target image information.

As shown in FIG. 2A, the color space 201 of the target image information is included in the color reproduction range 200. Figure 2
As shown in (b), the color reproduction range 200 is included in the color space 201 of the target image information. As shown in FIG. 2 (c),
Part of the color space 201 of the target image information is the color reproduction range 200.
include. As shown in FIG. 2D, the color space 201 of the target image information is not included in the color reproduction range 200.

FIG. 2A shows that the image is within the color reproduction range of the image output device 102 and that the image can be output. Therefore, normal color processing (R / G / B → C / M / Y conversion etc.) is performed. Can be obtained. However, in FIGS. 2B to 2C, since the area outside the color reproduction range 200 is included, processing for virtually narrowing the color reproduction range of the color space 201 of the target image information (hereinafter referred to as compression processing). Described).

The present invention relates to a determination process as to whether or not to perform such a compression process, and more specifically, an inside / outside determination is made as to whether or not the target image information is within the color reproduction range of the image output device 102. The parameters used in this case can be easily constructed, and the inside / outside determination processing can be performed easily.

Construction of Virtual Device (VD) in Image Processing Device 107 Next, a virtual device (VD: Vir) used for inside / outside determination processing.
(Tal Device) will be described. In the first embodiment, a virtual image output device (VP: Virtual P) is used as a virtual device in the image processing device 107 of the system of FIG.
to build and utilize a printer.

FIG. 3 is a flowchart showing a method of creating the virtual image output device VP. First, the actual image output device 102 outputs N color samples (S30).
1). Here, the color samples are CMY single colors and CMs.
A set of four patches of Y color mixture is output so that the maximum color reproduction range of the image output device 102 can be obtained.

Next, the densities cmy (three color printers of cmy are assumed in this example) of the three monochromatic patches of the output color sample and the L * a * b * values of the mixed colors are measured (S3).
02), the parameters of the virtual image output device VP are calculated by the neural network having these inputs and outputs (S303). A parameter in the neural network whose input is cmy and whose output is L * a * b * is called a forward VP, and a parameter when input and output are reversed is called a backward VP.

FIG. 4 shows an example of the structure of the virtual image output device VP, which is composed of a neural network using backpropagation here. It comprises an input layer having an input number p, intermediate layers 1 and 2 having an element q, and an output layer having an output number r. In this example, p and r of the input / output layer are 3. Also, the above parameters p, q, and r are determined so that the input / output values are minimized.

By using the calculated parameters, in the forward VP, the L * a * b * values expected to be actually output from the arbitrary cmy concentration data can be obtained. Therefore, for the backward direction VP, if L * a * b * within the color reproduction range of the image output device 102 is input, the value of cmy, which is the solution, falls within the range of the actually measured density data. In other words, any image information is converted into L * a * b *, and if this value is outside the color reproduction range of the image output device 102,
At least one value of the solution cmy deviates from the actually measured concentration data range. Therefore, the inside / outside determination processing of the color reproduction range of the image output apparatus 102 for arbitrary image information can be performed.

Further, for example, if the reverse direction VP between RGB and L * a * b * is obtained, L * a * outside the color reproduction range is obtained.
For b * input, at least one solution of the output RGB has a negative value or a value larger than 255 (when each of RGB is 8 bits), so that the inside / outside determination processing of the color reproduction range can be similarly performed.

Inside / Outside Judgment Processing of Color Reproduction Range Next, referring to the flowchart of FIG. 5, inside / outside judgment processing using the virtual image output device VP (reverse direction VP) constructed by the neural network shown in FIG. Will be described. First, image information (RGB data) is converted into tristimulus values XYZ (S501), and XYZ is L * a * b.
Convert to * (S502). Next, the virtual image output device VP calculates cmy in the reverse direction VP (S50).
3).

Subsequently, it is determined whether all the calculated cmy are within the actually measured density range of the image output device 102 (S5).
04), if it is within the range, it is determined to be within the color reproduction range of the image output device 102 (S505). On the other hand, if it is outside the range, it is judged to be outside the color reproduction range of the image output device 102 (S506).

After the inside / outside determination process is performed in this way, if the color reproduction range is outside (the relationship shown in FIGS. 2B to 2D), the compression process of the target image information is executed. The data is converted so that it falls within the color reproduction range of the image output device 102.

As described above, in the first embodiment, the virtual image output device VP and the image output device 102 in the opposite direction VP are used.
In step S504 of the inside / outside determination processing, it is determined whether or not all the cmy (input color image information) is within the actually measured density range (that is, the color reproduction range of the image output device 102). The inside / outside determination process can be easily performed. Further, since the virtual image output device is constructed by using the neural network, it is possible to easily construct the parameter used when determining whether the target image information is within the color reproduction range of the image output device 102. You can
It is also easy to change the parameters.

[Embodiment 2] In Embodiment 1, as shown in FIG. 5, an example is shown in which after the inside / outside determination processing is executed on the target image information, the compression processing is executed when it is outside the color reproduction range. However, in deciding whether to execute compression processing,
If the inside / outside determination process is executed for all the pixels of the target image information, the calculation load in the backward VP increases,
In the case of a large image, it may take time to make a judgment. Therefore, in the second embodiment, the uniform color space is divided into a plurality of areas, the target image information existing in each area is represented by one piece of representative information, and the representative information (the representative point of the image) is represented.
Uses to speed up the calculation. In addition, the number of pixels of the input color image information existing in each area is counted for each area, and it is determined whether the representative information is within the color reproduction range of the image output device 102 to determine the color. If the ratio of the total number of pixels corresponding to the representative information determined not to be within the reproduction range and the total number of pixels of the target image information is calculated, and the calculated ratio exceeds a predetermined value (threshold value), the target image information The linear compression is performed on.

Since the structure of the second embodiment is similar to that of the first embodiment, its illustration and description will be omitted.

In the second embodiment, first, as shown in FIG.
A wide color space that completely includes the color reproduction range 600 of the image display device 103 and the color reproduction range of the image output device 102 is divided in advance into i * j * k spaces in each L * a * b * axis direction. (Hereinafter, referred to as a divided space), the number of pixels included in each divided space is calculated for all pixels.

Here, assuming that a wide color space is L _min ≤L * ≤L _max a _min ≤a * ≤a _max b _min ≤b * ≤b _max , the division pitches PL, Pa, Pb of the respective axes are , PL = (L _max −L _min ) / i Pa = (a _max −a _min ) / j Pb = (b _max −b _min ) / k Therefore, when the input of a certain pixel is L0, a0, b0 , The coordinates of the corresponding divided space Sd are: Sd = (int (L0 / PL), int (a0 / Pa), i
nt (b0 / Pb)) (however, int () is rounded down after the decimal point).

At this time, the pixel counter (not shown) corresponding to the divided space Sd is incremented by 1. If the count-up is the first in a certain divided space, the L * a * b * value is saved together with the coordinate Sd of the divided space. When the counting (counting) of all the pixels in the corresponding divided space is completed, the inside / outside determination of the divided space itself is performed. The L * a * b * values used for the inside / outside determination processing are executed for all the divided spaces by representing the center of gravity of the divided space or one of the eight vertices of a rectangular parallelepiped.

As a result, as shown in FIG. 7, only the representative value 703 of the divided space for the target image information remains. FIG. 7 is a view of L * a * b * of FIG. 6 viewed from directly above, where a * b * is divided into j × k. When the distribution of the target image information is 701, the space in which the representative value 703 exists in each divided space 702 is shown by diagonal lines. Each representative value 703 of the space indicated by this diagonal line is saved.

After that, based on the saved L * a * b * of all the divided spaces indicated by the diagonal lines, the inside / outside determination processing of the color reproduction range of the image output device 102 is performed by the same method as in the first embodiment. Specifically, it can be realized by rotating the loop from A in FIG. At this time, the total sum IP of the number of pixels belonging to the divided space determined to be inside the color reproduction range is obtained, and the total sum IP
And the total number of pixels TP of the target image information, the content rate α (= IP
/ TP) is calculated, and when the content rate α exceeds a preset threshold Th, the compression process is executed.

Here, the threshold value Th is set in order to prevent the compression of an image in which almost all the pixels are within the color reproduction range due to a small number of pixels outside the color reproduction range. Is.

FIG. 8 shows a flow chart of the compression determination process including the saving of the representative value of each divided space, the counting of the number of pixels of each divided space, the calculation of the content rate α, and the determination of the presence or absence of the compression process. First, the image processing apparatus 107 determines whether or not the processing of all pixels TP of the target image information has been completed (S801), and until all pixels TP are completed, step S8.
02 to S806 are repeated. On the other hand, if all the pixels TP have ended, the process proceeds to step S807.

In steps S802 to S806, pixels (RGB data) are converted into tristimulus values XYZ (S80
2), XYZ is converted to L * a * b * (S803), L
The divided space to which * a * b * belongs is counted up (S804), and if it is the initial count up of the divided space (that is, the first count up) (S80).
5), save space coordinates and L * a * b * values (S80)
6).

In step S807, it is determined whether the inside / outside determination of all divided spaces has been completed. If not finished,
The inside / outside determination processing of the divided space is executed, and if the corresponding divided space is inside (S808), the sum total IP of the number of pixels belonging to the divided space is obtained (S809), and the process returns to step S807.

If the inside / outside determination of all the divided spaces is completed,
The content rate α (= IP / TP) is obtained (S810), the content rate α is compared with the threshold Th (S811), and if α ≧ Th, the compression process is executed (S812). On the other hand, α <Th
If so, non-compression processing is executed (S813).

Here, the non-compression processing means that normal image processing (processing of steps S911 to S913 of FIG. 9 described later) is executed without performing compression processing.

Next, referring to the flowchart of FIG.
The compression process of step S812 of FIG. 8 will be described.
In the compression process, the representative points (L1, a1, b), which are the representative values of the divided space, are set for all the divided sections TD in which the image exists.
1) Linearly compress point (Lg, a0, b0). Here, when Lg is 50 and the compression rate is ke, for example, the coordinate points (L2, a2, b2) after compression are obtained as follows. L2 = L- (L-Lg) (1-ke) a2 = (1-ke) a1 b2 = (1-ke) b1 The representative score CD included in the color reproduction range of the image output apparatus 102 is calculated and included. The rate β (= CD / TD) is obtained (S901 to S906).

The initial compression rate ke is set small, and the compression rate ke is gradually increased by adding the pitch δ until the content rate β becomes larger than the threshold value Thd (S907, S908, S901 to S906).

When the content rate β becomes larger than the threshold value Thd, the compression rate ke at that time is determined as the compression rate (S9
09), the entire image is compressed by that value (S910).

Thereafter, color correction processing is executed (S91
1), an image is displayed on the image display device 103 (S91
2) Output to recording paper via the image output device 102 (S913).

FIG. 10 shows the flow of image data in each processing of steps S911 to S913.
Arrows represent color correction and image display, and arrows represent image output. In the case of recording paper (printed matter, photograph, etc.), it is read as RGB digital data by the correction CCs using the image reading device 101. Since the CG image or the like is created using the image display device 103 or the like, it is RGB data from the beginning.

This RGB data has a 3 × 3 determinant ai
j is converted into tristimulus values XYZ, and L is converted by the function f ().
ab (L * a * b *). Then, it is compressed into L'a'b 'by the compression process and returned to the tristimulus value X'Y'Z' by the function g (). Next, the density cmy is obtained by the correction CCp in the image output device 102, γ conversion is performed to correct the gray to obtain c′m′y ′, and L ″ a ″ b ″ is obtained by the virtual image output device VP. To obtain X ″ Y ″ Z ″ by the function g () and R′B′G ′ by the inverse matrix bij of aij.

That is, it is R'B'G 'that the image information obtained by the output of the actual machine (image output device 102) is virtually created by the virtual image output device VP. This series of processes is called color processing. Further, displaying R'B'G 'on the image display device 103 is referred to as image display.
When actually outputting on recording paper, c ′ after γ conversion
The m'y 'is switched as shown by the arrow, and the conversion table LUT for sending to the image output device 102 is passed. This is image output.

As input / output of the virtual image output device VP, it is possible to construct not only the density cmy as in the present embodiment, but also the reflectance integral value of each monochromatic color, RGB or the like. Also, data other than L * a * b * can be considered as a pair of data. Further, the three-color system of cmy and the four-color system of cmyk can be constructed, and in that case, it is necessary to change the color processing so as to match the input / output data.

As described above, according to the second embodiment, in addition to the effect of the first embodiment, the determination process is speeded up, and the color image is affected by a small number of pixel data outside the color reproduction range, and the overall color image is affected. You can avoid losing color. Further, it is possible to avoid losing the color tone as a whole by compressing the color image.

Regarding the creation of the divided space, considering the direction of one axis, it is possible to apply not only the uniform division but also a dividing method such as increasing the width of the division as the distance from the reference point increases.

[Third Embodiment] In the third embodiment, the compression in the second embodiment is variable according to the division space.
Since the basic configuration and operation are the same as those in the second embodiment, only different parts will be described here.

In the second embodiment, as shown in FIG. 11A, the color space is widened and set to set the division space. In the third embodiment, as shown in FIG. 11B, the sub-compression ratio for each area shown in four stages in the figure is set in advance so that the compression ratio increases in the saturation direction as the distance from the origin increases. . Similarly, for the L * axis, as shown in FIGS. 11C and 11D, the sub compression rate is set around (Lg, 0, 0).

Here, the sub compression rate will be described. For example, in FIG. 11B, since the sub-compression rate is set in four stages, if the sub-compression rate is set to k0 to k3 in the direction away from the center according to each level, when the compression rate is ke , A * b *, the compression ratio of each space is k0 (1-
ke), k1 (1-ke), k2 (1-ke), k3
(1-ke).

However, with respect to the compression rate at each stage, each sub-compression rate is adjusted so as not to get inside. Taking a compression rate of 20% as an example, from ke = 0.2 to (1-ke)
The product of and is k0 = 1, k1 = 0.875, k2 = 0.7
5, k3 = 0.625, 0.8,
It becomes 0.7, 0.6, 0.5. Therefore, 20 from the inside
%, 30%, 40%, 50% compression.

FIG. 12 shows a flow chart of the compression processing of the third embodiment, which is basically the same as the compression processing of the second embodiment shown in FIG. 9, and the same reference numerals indicate common processing. Here, only different parts will be described. A representative point (L1, a1, b1) that is a representative value of the divided space is a point (Lg, a0, b0) for all divided sections TD in which an image exists.
Variable compression is performed for each divided space (S1201). Here, Lg is, for example, 50, and when the compression rate ke and the sub-compression rate ks of the divided space are, coordinate points (L2, a2, after compression)
b2) is calculated as follows. L2 = L- (L-Lg) (1-ke) ks a2 = (1-ke) ks.a1 b2 = (1-ke) ks.b1

Thereafter, as in the second embodiment, the representative score CD included in the color reproduction range of the image output device 102 is obtained, and the content rate β (= CD / TD) is obtained (S901 to S901).
906).

As described above, in the third embodiment, the sub-compression rate is set so that the compression rate for each area in the linear compression can be changed, so that the compression rate is increased for data farther from the compression reference point, It is possible to reduce the loss of color when an image is compressed. In other words, it is possible to avoid losing the color tone as a whole by compressing the color image.

[Fourth Embodiment] In the fourth embodiment, steps S910 to S912 surrounded by dotted lines in the flowchart of the compression process of the third embodiment are replaced with steps S1301 to S1301 of FIG.
It is replaced by S1309.

In the third embodiment, the compression ratio is automatically calculated, and the image display / image output is performed. However, depending on the user, rather than avoiding the fading of the overall tint, the high density portion is output vividly. Sometimes I want to do it. Therefore, in Example 4,
The compression rate ke is used as a standard for compression, and the compression rate kef finally applied to the image information can be set by the user.

First, when the user uses the operation / input device 105 to specify an area for temporary processing of an image for checking the state after compression processing (S1301), the specified area is compressed at a compression rate ke. (S1302), color correction is performed (S1302)
1303) and an image is displayed (S1304). The user confirms the image displayed on the image display device 103, and if the image does not have the desired hue, the operation / input device 1
The compression rate ke is set via 05 (S1305, S
1306). Subsequently, returning to step S1302, the designated area is compressed at the designated compression rate ke, and step S1 is performed.
Step 303 and subsequent steps are repeated.

On the other hand, if the displayed image is a desired image, the user depresses a predetermined key of the operation / input device 105 and inputs the compression ratio setting end (S130).
5) With the compression rate ke at that time as the compression rate kef, the entire image is compressed at the compression rate kef (S1307), color correction is performed (S1308), and the image is displayed (S130).
9).

As described above, according to the fourth embodiment,
When the user sets the compression rate via the input device 105 (compression rate setting means), the compression rate is used to perform linear compression on the image information. In other cases, the compression rate automatically determined. Since the image information is linearly compressed based on the above, in addition to the effect of the third embodiment, the image can be compressed at a compression rate of a value that the user can tolerate.
In other words, the user can set the compression ratio that he / she can tolerate, so that the user can obtain a color image that he / she likes.

[Embodiment 5] The image output apparatus 102 does not always output the same output for a certain fixed input (CMY data). This is due to changes over time in the image output device 102 and environmental changes during output. In addition, there are factors that change with time, in the long term, in the medium term, and in the short term. Taking a copying machine as an example, typical factors include the amount of toner replenishment and the fluctuation of the charging voltage to the photosensitive drum.

Therefore, in the fifth embodiment, in addition to the configurations of the first to fourth embodiments, a sensor for measuring such a change over time and a sensor for measuring the environment (for example, a humidity sensor) are output as images. It is arranged in the device 102, and by utilizing the sensor information measured by these sensors in the virtual image output device VP, it is possible to virtually create an image that matches the current state of the output machine (image output device 102). is there.

Specifically, the image output device 102 is arranged in advance in the environment room to perform image output, or image output is performed in a situation where a change over time is created by an acceleration test or the like. The sensor information at that time is measured.

Next, the sensor information is divided into cases according to the environment and changes with time, and the VP parameters are calculated for each case, stored as a library.

Then, from the sensor information during actual operation,
The most suitable VP parameter is extracted and used for image processing.

FIG. 14 shows a configuration example for determining the VP parameter in the fifth embodiment. When the sensor information processing unit 1401 inputs sensor information from a sensor group (sensor 1 to sensor n) arranged in the image output device 102, the sensor information processing unit 1401 determines a situation of environment / time change from the sensor information and is suitable for the determined situation. The address of the VP parameter is output. The VP library 1402 has an environment
The VP parameters, which have been classified according to the change over time, are stored in the form of a library.
When the address of the VP parameter is input from, the corresponding VP parameter is output.

The virtual image output device VP shown in FIG.
Performs a backward VP process using the VP parameters output from the VP library 1402, thereby virtually creating an image that matches the current state of the image output device 102.

As described above, according to the fifth embodiment, it is possible to promptly deal with changes with time and environmental changes of the connected image output device. Further, for example, even when the connected image output device is replaced, the optimum VP parameter is automatically selected based on the sensor information of the newly installed image output device, so that the optimum image compression is performed. Processing can be performed.

[Sixth Embodiment] In the sixth embodiment, in order to perform the optimum processing according to the change with time and the environmental change, the change with time and the environmental change are measured in addition to the configurations of the first to fourth embodiments. A sensor group (sensor 1 to sensor n) and a time-dependent change / environment correction unit that corrects image data (L * a * b *) after processing by a virtual image output device VP based on sensor information from the sensor group. And 1501 are arranged.

The virtual image output device VP converts the input density cmy into L * a * b *. After that, the sensor information and the acquired information are acquired, and the correction data L * 'a *' b * 'are obtained by the change / environment correction unit 1501.

As described above, according to the sixth embodiment, it is possible to promptly deal with changes with time and environmental changes of the connected image output device. Further, for example, even when the connected image output device is replaced, the image data is corrected based on the sensor information of the newly installed image output device, so that optimum image compression processing can be performed. it can.

[0095]

As described above, in the color image processing apparatus according to the first aspect of the present invention, the virtual device means performs the processing in the opposite direction to the color image output device, and the determining means outputs the output color image information of the virtual device means. It is determined whether the input color image information is within the color reproduction range of the color image output device in order to determine whether the input color image information is within the color reproduction range of the color image output device based on It is possible to easily construct the parameters to be used when making the judgment and to make the judgment process simple.

In the color image processing apparatus according to the second aspect, the uniform color space is divided into a plurality of areas, and the input color image information existing in each area is represented by one representative information for each area. Since the representative information (representative points of the image) is used, the calculation speed can be increased. Further, the number of pixels of the input color image information existing in each area is counted for each area, and it is determined whether or not the representative information is within the color reproduction range of the color image output device. If the ratio of the total number of pixels corresponding to the representative information determined to be not to the total number of pixels of the input color image information is found, and the found ratio exceeds a predetermined value (threshold value), the input color image Since the information is linearly compressed, it is possible to prevent the color image from being affected by a small number of pixel data outside the color reproduction range and losing the overall tint.

Further, in the color image processing apparatus according to the third aspect, the compression rate can be changed for each area in the linear compression means, and the compression rate can be increased for data farther from the compression reference point. It is possible to reduce the loss of color when an image is compressed.

Further, in the color image processing apparatus according to the fourth aspect, when the user sets the compression rate through the compression rate setting means, the color image information input using the compression rate is linearly compressed, In other cases, linear compression is performed on the input color image information based on the compression rate determined by the compression rate determining means, so that the user can set the compression rate that he / she can accept, and the user's favorite color can be set. Images can be obtained.

Further, in the color image processing apparatus according to the fifth aspect, the compression rate determining means can calculate the compression rate for each area, and the compression rate can be increased as the data is farther from the compression reference point. It is possible to reduce the loss of color when an image is compressed.

A color image processing apparatus according to a sixth aspect measures a temporal change / environmental change of the color image output apparatus and considers the temporal change / environmental change of the color image output apparatus in advance based on the measurement result. The optimum parameter is selected from among the plurality of parameters set as described above, the virtual device means performs processing in the opposite direction to the color image output device, and the determination means determines the color image output device based on the output color image information of the virtual device means. , In order to determine whether the input color image information is within the color reproduction range of the color image output device, when the connected color image input device or color image output device is replaced, It is possible to promptly respond to changes with time and environmental changes of existing color image output devices.

Further, the color image processing apparatus according to the seventh aspect of the present invention performs the processing in the opposite direction to the color image output apparatus by the virtual device means. In addition, the change over time of the color image output device
The environmental change is measured, the output color image information obtained in the reverse processing is corrected based on the measurement result, and the input color image information is corrected by the determination means based on the corrected output color image information. In order to determine whether the color image output device is within the color reproduction range, when the connected color image input device or color image output device is replaced, or when the connected color image output device is It is possible to quickly respond to changes over time and environmental changes.

[Brief description of drawings]

FIG. 1 is a system block diagram of a color digital multi-function peripheral equipped with a color image processing apparatus of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a color reproduction range of an image output device and target image information.

FIG. 3 is a flowchart showing a method of creating a virtual image output device VP.

FIG. 4 is an explanatory diagram showing a configuration example of a virtual image output device VP.

5 is a flowchart of an inside / outside determination process using a virtual image output device VP (reverse direction VP) constructed by the neural network shown in FIG.

FIG. 6 is an explanatory diagram showing a divided space according to the second embodiment.

7 is a diagram of L * a * b * of FIG. 6 viewed from directly above,
It is explanatory drawing which shows the representative value of a division space.

FIG. 8 is a flowchart of a compression determination process including saving a representative value of each divided space, counting the number of pixels in each divided space, calculating a content rate α, and determining whether or not a compression process is performed in the second embodiment.

9 is a flowchart of a compression process of step S812 of FIG.

10 is an explanatory diagram showing a flow of image data in each processing of steps S911 to S913 of FIG. 9. FIG.

FIG. 11 is an explanatory diagram showing setting of a sub compression rate in the third embodiment.

FIG. 12 is a flowchart of a compression process according to the third embodiment.

FIG. 13 is a flowchart showing a part of the compression processing of the fourth embodiment.

FIG. 14 is an explanatory diagram showing a configuration example for determining a VP parameter according to the fifth embodiment.

FIG. 15 is an explanatory diagram showing a configuration example of a sixth embodiment.

[Explanation of symbols]

 101 image reading device 102 image output device 103 image display device 104 storage device 105 operation / input device 106 control device 107 image processing device 1401 sensor information processing unit 1402 VP library 1501 temporal change / environment correction unit VP virtual image output device (virtual Device means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G09G 5/02 B 9471-5G L 9471-5G H04N 1/46 G06F 15/68 310 A H04N 1 / 46 Z

Claims (7)

[Claims] 1. A color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of the color image output apparatus, wherein an output color image in the color image output apparatus is provided. Information corresponding to input color image information, input color image information corresponding to output color image information, and virtual device means for performing processing in the opposite direction to the color image output device; and output color image information of the virtual device means. A color image processing apparatus comprising: a determination unit that determines whether the input color image information is within a color reproduction range of the color image output apparatus based on the determination result. 2. A color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of a color image output apparatus, wherein a uniform color space is divided into a plurality of areas. Then, the image information representative means for representing the input color image information existing in each area by one representative information for each area, and the number of pixels of the input color image information existing in the area for each area Pixel number counting means for counting, determination means for determining whether or not the representative information is within the color reproduction range of the color image output device, and representative information determined by the determination means for not being within the color reproduction range Ratio calculating means for obtaining a ratio of the total number of pixels corresponding to the above and the total number of pixels of the input color image information,
A color image processing apparatus comprising: a linear compression unit that linearly compresses the input color image information when the ratio calculated by the ratio calculation unit exceeds a predetermined value. 3. The color image processing apparatus according to claim 2, wherein the linear compression unit can change the compression rate for each area. 4. A color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of a color image output apparatus, wherein a uniform color space is divided into a plurality of areas. Then, the image information representative means for representing the input color image information existing in each area by one representative information for each area, and the number of pixels of the input color image information existing in the area for each area Pixel number counting means for counting, determination means for determining whether or not the representative information is within the color reproduction range of the color image output device, and representative information determined by the determination means for not being within the color reproduction range Ratio calculating means for obtaining a ratio of the total number of pixels corresponding to the above and the total number of pixels of the input color image information,
When the ratio calculated by the ratio calculating unit exceeds a predetermined value, a compression ratio determining unit that determines the compression ratio by a preset calculation, and a compression ratio setting unit that allows the user to set the compression ratio. When the compression rate is set through the compression rate setting means, the compression rate is used to perform linear compression on the input color image information, and otherwise, the compression rate determination means determines the compression rate. A color image processing apparatus comprising: a linear compression unit that linearly compresses the input color image information based on the compressed rate. 5. The color image processing apparatus according to claim 4, wherein the compression rate determining means calculates a compression rate for each area. 6. A color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of the color image output apparatus, wherein an output color image in the color image output apparatus is provided. Information corresponding to input color image information, input color image information corresponding to output color image information, and virtual device means for performing processing in the opposite direction to the color image output device; and output color image information of the virtual device means. Based on the input color image information, a determination means for determining whether or not the input color image information is within a color reproduction range of the color image output device; and a measurement means for measuring a temporal change / environmental change of the color image output device. The virtual device means is based on the measurement result of the measuring means, and in consideration of temporal change and environmental change of the color image output device in advance. A color image processing apparatus, wherein an optimum parameter is selected from a plurality of set parameters to perform the processing in the reverse direction. 7. A color image processing apparatus for performing color correction processing for correcting input color image information into color image information within a color reproduction range of the color image output apparatus, wherein an output color image in the color image output apparatus is provided. Information corresponding to input color image information, input color image information corresponding to output color image information, and virtual device means for performing processing in the opposite direction to the color image output device; and output color image information of the virtual device means. Based on the input color image information, a determination means for determining whether or not the input color image information is within a color reproduction range of the color image output device; and a measurement means for measuring a temporal change / environmental change of the color image output device. A correction means for correcting and outputting the output color image information obtained by the processing in the reverse direction based on the measurement result of the measurement means. Color image processing device to be used.