JP3314245B2 - Image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus particularly suitable for printing on building materials for printing patterns such as wood grain and grain.

[0002]

2. Description of the Related Art In a printing field such as a publication, a large number of colors are expressed by using four process inks of cyan C, magenta M, yellow Y, and sumi K. On the other hand, in the field of building material printing for expressing patterns such as wood grain and grain, special color printing using a special color ink is mainly performed.

FIG. 3 shows a color distribution of a natural image in a printing field such as a publication and a color distribution of a building material pattern in a printing of a building material. As shown in FIG. When printing using a special color ink, there are colors that cannot be reproduced. In contrast, most patterns in building material printing have color bias,
Since it is not necessary to reproduce all colors, printing using a special color ink is mainly performed. For example, since a wood grain pattern is usually mainly brown, printing is performed using a brown special color ink, and ink of another color, for example, a black ink is used to express a wooden conduit. Ordinary building material printing is printing using three to four colors of ink including a special color.

[0004] In general, the special color ink means a special ink that cannot be obtained by blending a process ink, such as gold, silver, and fluorescent colors used in publishing printing. Also means an ink obtained by blending

Here, the printing process of building material printing will be described.
First, get the actual thing such as wood to be expressed, shoot this actual thing with a large camera, and through a color filter,
It is baked on a full-scale film to create a film master for three to four colors. At this time, the color filter used is usually R
Although GB is used, the operator may select it as appropriate.

Next, the obtained film original is corrected, a reflection original is created, and a printing plate for gravure printing is created using an electronic gravure engraving apparatus. Next, an ink is appropriately selected, and proof printing is performed using the obtained printing plate. if,
If the desired color is not expressed, the ink is blended again and proof printing is performed again. When a desired color is expressed, printing is performed using this ink, and a printed matter is created.

[0007] However, most of the steps of correcting the film original in the printing process depend on manual work.
In particular, when the work of correcting the film original is required, there is a problem that the work load is large and the work efficiency is not good.

On the other hand, a color positive film obtained by photographing a grain or the like is separated into four colors of CMYK using a plate making scanner used in publishing printing and the like, and a film master is created based on the color separation data. Then, gravure printing may be performed. When this plate making scanner is used, it is possible to provide data to an image processing device that performs image processing on the color separation data expressed in CMYK four colors, and by using this image processing device, it is possible to easily correct an image. There is an advantage that it can be performed.

[0009]

However, current plate making scanners cannot separate colors with colors other than CMY or CMYK, and the image processing apparatus connected to this plate making scanner is also CMY or CMYK. Only the processing using the color separation data represented by is performed. Therefore, when color separation is performed using a current plate-making scanner, printing is performed using process ink to obtain a printed material.

For this reason, for example, when printing a wood grain pattern,
Since a color such as brown, which is the main body of printing, is expressed by a combination of four CMYK colors, there is a problem that the expressiveness of gradation is inferior to the case where a brown special color ink is used. Accordingly, an object of the present invention is to provide an image processing apparatus capable of improving the expressive power of a special color gradation of a printed matter mainly composed of a special color.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is represented by CMYK or CMY.
Special color vector selection means for selecting the most frequent color vector based on each color density of the color separation data to obtain a special color vector (Uc, Um, Uy); and for each pixel of the color separation data, Special color component calculation means for calculating a special color component (u) of the special color vector under a constraint condition not exceeding each color density, and for each pixel of the color separation data, converting each color density of the color separation data to the special color component (u). by difference in concentrations of features represented by the auxiliary color component (c, m, y) and the complementary color component calculating means for calculating a, it is obtained by configuring the image processing apparatus by.

[0012]

According to the present invention, the most frequently used color vector is selected by the special color vector selecting means based on each color density of the color separation data represented by CMY or CMYK, so that the special color vector (Uc, Um, Uy) is obtained, and the special color component calculation means gives the special color component (u) of the special color vector under a constraint condition that does not exceed each color density of the color separation data. For pixels that cannot be reproduced by the special color component (u), the auxiliary color component (c, m, y) is calculated by the auxiliary color component calculation means.

The obtained special color component (u) is used for preparing a special color plate, and the auxiliary color components (c, m, y) are used for forming a cyan, magenta and yellow auxiliary color plate. It is used when doing. The special color vector is given by each color density of cyan, magenta, and yellow, and corresponds to the color of the special color ink used in printing, and indicates the composition of each ink.
Using the special color plate and the auxiliary color plate, printing is performed with a special color ink and cyan, magenta, and yellow inks to obtain a printed material.

As described above, according to the image processing apparatus of the present invention, the color represented in the CMY coordinate system is represented by using the most frequently used special color vector, and is represented by using this special color vector. In the image, especially when the color distribution is biased, the expressive power of the gradation of the special color is greatly improved.

Further, the feature of the picture is sufficiently extracted from the special color plate. If the special color plate is printed with ink of a different color, a printed material having the same pattern and a different color can be easily obtained. In addition, since most inks are used for the special color plate, the amount of ink used can be reduced.

[0016]

Embodiments of the present invention will be described below in detail.
FIG. 1 is a block diagram of an image processing apparatus according to the present invention. Reference numeral 1 denotes an input scanner that generates color separation data of cyan C, magenta M, yellow Y, and sum K by separating a document image. Each value of the color separation data of the four CMYK colors indicates the density of each pixel, and is given in the range of 0 to 100%.

Reference numeral 2 denotes a storage device for storing the input color separation data, 3 an output scanner for outputting to a film based on the color separation data, and 4 a control device for controlling input / output of image data. , 5 receive the color separation data of the four CMYK colors stored in the storage device 4,
This is an image processing apparatus that converts color-separated data (u, c, m, y) using colors. Here, U means the feature.

In this image processing apparatus 5, reference numeral 51 denotes C
This is a special color vector selection unit that obtains a special color vector U by calculating using each color density of the color separation data of MYK four colors and selecting a color vector with the highest frequency.

Reference numeral 52 denotes a special color component calculation unit that obtains a special color component (u) by obtaining the maximum value of the special color component of the special color vector U under a constraint condition that does not exceed each color density of the color separation data.

Reference numeral 53 denotes each color density of the color separation data,
An auxiliary color component calculation unit that calculates an auxiliary color component (c, m, y) by calculating a difference between the density of the special color obtained by using the special color vector U and the special color component (u).

The image processing apparatus 5 is connected to a display used for interactively correcting an image, a keyboard as an instruction means, and the like.
In the present invention, illustration is omitted because there is no direct relation.

Next, the processing operation of the image processing apparatus according to the present invention will be described. FIG. 2 is a flowchart for explaining the processing operation of the image processing apparatus of the present invention, and is based on color separation data of four CMYK colors obtained by performing color separation on a document.
This shows the process up to creation of color separation data of four UCMY colors using the special color U.

The processing features vector by first scanning the set on the drum of the input scanner 1 document in S1, the color separation data (C,
M, Y, K) are obtained. This manuscript may be a handwritten manuscript created by a designer or a color positive created by photographing a real object such as wood. The obtained color separation data is stored in the storage device 4.

Next, the processing of S2 to S4 is performed using the special color vector selection means 51. In S2, the color separation data (C, M, Y, K) obtained in S1 is converted to the color density (C
+ K, M + K, Y + K), multiply by the scale value k, and convert to a color vector (C ′, M ′, Y ′). This equation is shown by equation (1). Note that the scale value k is a scale value k such that at least one component of the color vectors (C ′, M ′, Y ′) is 1.

[0025]

## EQU1 ## Color vector (C ', M', Y ') = k (C + K,
M + K, Y + K) (1)

Here, the color output from the input scanner 1 is C
In the case of MY, the calculation may be performed with K = 0 in equation (1). In this case, the same applies to the following equations (2) to (7). Therefore, the image processing apparatus of the present invention
The “each color density of the color separation data” obtained by the input scanner 1 in the
When the color separation is performed by the color, the color density obtained by the above conversion is (C + K, M + K, Y + K), and the color density when the color separation is performed by the three CMY colors is (C, M, Y). Both meanings shall be included.

Then, in S3, based on the color vector (C ', M', Y ') obtained in S2, each component is
The frequency of the color vector is calculated for the 163 combinations divided into steps.

Subsequently, in S4, the color vector having the highest frequency among the frequencies calculated in S3 is selected, and this color vector (C ', M', Y ') is selected as the special color vector U. Hereinafter, each color density of this special color vector U is defined as (Uc, Um, Uy).

Calculation of Special Color Component u Next, in S5, the special color component calculation means 52 is used to calculate the special color component (u) of the special color vector for each pixel. The processing is as follows. The special color component (u) is
The maximum value that does not exceed the respective color densities of the color separation data obtained by the input scanner 1 and that satisfies the following equations (2) to (4) is the special color component (u). Since one of the three components of the special color vector U is 1, the special color component (u) is obtained with a value in the range of 0 to 100%.

[0030]

U × Uc ≦ C + K (2) u × Um ≦ M + K (3) u × Uy ≦ Y + K (4)

The calculation of the auxiliary color component Next, in S6, by using the complementary color component calculation means 53, complementary color component (c, m, y) is calculated for each pixel. In this calculation, since colors that cannot be represented by the special color component (u) need to be supplemented by using auxiliary colors, cyan, magenta, and yellow color components to be used as the auxiliary colors are obtained. This auxiliary color component (c, m,
y) is obtained by subtracting each color density of the color separation data by a density that can be represented by a special color, and is calculated using the following equations (5) to (7). In addition, each color component c, m, y is obtained in the range of 0 to 100%. The density represented by this special color is u for the cyan component.
× Uc.

[0032]

C = C + K−u × Uc (5) m = M + K−u × Um (6) y = Y + K−u × Uy (7)

By the above processing, the color separation data (C, M, Y, K) obtained by the input scanner 1 is converted into the color separation data (u, c, m, y) using the special color U. Will be. At this time, the special color component (u) is
Since it is obtained as the maximum value within the range not exceeding the density of each color component of the color separation data, 3 of the auxiliary color component (c, m, y) is obtained.
One of the color components is always 0. Therefore, the entire image is represented by the four colors of the special color U and the auxiliary color CMY, but each pixel is represented by the three colors.

The special color component (u) and the auxiliary color components (c, m, y) obtained by the above processing are converted to the special color vector U
At the same time, it is stored in a storage device (not shown) of the image processing device 5.

Subsequently, the converted color separation data (u, c,
m, y) is output to the output scanner 3 and includes the spot color U.
A film original for each color is created, and a printing plate for four colors including a special color plate is created using this film original. Using this printing plate, printing is performed with the special color ink indicated by the special color vector (Uc, Um, Uy) and each of the CMY inks.
Printed materials such as wood grain patterns are obtained.

According to the embodiment described in detail above, the most frequent color vector is extracted as the special color vector U, a printing plate is obtained by obtaining the special color component (u) of the special color U, and the printing plate is printed with the special color ink. The printed matter is obtained by performing
In building material printing mainly using printing using a special color, there is an effect that the gradation expression power of the obtained printed matter is greatly improved.

Further, since most of the ink is used for the special color plate obtained in this embodiment, the amount of ink used can be reduced by about 50% as compared with the case where process ink is used.

Further, since the features of the pattern are sufficiently extracted from the special color plate obtained by the present embodiment, the color can be easily formed with the same pattern by printing the special color plate using another color ink. There is an effect that different printed matter can be obtained.

Further, one of the auxiliary color components (c, m, y) obtained in the embodiment is 0, and all the pixels have been converted so that they are expressed in three colors. In this case, the effect of the misregistration is reduced.

It should be noted that the present invention is not limited to the one shown in the above-described embodiment. For example, instead of the configuration in which the film is output by the output scanner 3, the color separation data including the special color U is directly sent to the gravure electronic engraving machine. (U, c, m, y)
May be input to directly obtain a printing plate.

Further, the input scanner 1 is connected to the image processing apparatus 5.
A function for creating an endless image using the image input by the user and a processing function for correcting the created endless image are added, and after these image processings are performed, the processing according to the present embodiment is performed. Processing may be performed.

In addition to the function of selecting the most frequent color vector, the special color vector selection means 51 registers a special color vector to be preferentially selected in a storage device.
A function of selecting a special color vector may be added under the condition that the color density is within each color density of the color vector selected by the special color vector selecting means. In this case, by registering a commercially available ink or an ink that has been prepared as a special color to be preferentially selected, the operation of preparing the special color ink becomes unnecessary.

[0043]

According to the image processing apparatus of the present invention, the color vector (Uc, Um, Uy), which is the most frequently used color vector, is obtained using each color density of the color separation data. A special color component (u) of the special color vector (Uc, Um, Uy) is given under a constraint condition that does not exceed each color density. For a pixel that cannot be expressed only by the special color component (u), an auxiliary color component (c, m, y) ) Is given. A printing plate is prepared using the obtained special color component and auxiliary color component, and a printed matter mainly containing a special color is obtained.

Therefore, according to the image processing apparatus of the present invention, the color most frequently used as a spot color is selected as the spot color, and the tone of this spot color is represented by the spot color component (u). Therefore, an image represented using this special color vector has an effect that the gradation expression power is greatly improved particularly when there is a bias in the color distribution.

Further, since most of the ink is used for the special color plate prepared using the special color component (u) obtained by the image processing apparatus of the present invention, the amount of ink used can be reduced.

Furthermore, this special color plate has the feature of the picture pattern sufficiently extracted, and if the special color plate is printed with ink of another color, there is an effect that a printed matter in which the same pattern is changed in color can be easily obtained. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image processing apparatus according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the image processing apparatus according to the present invention.

FIG. 3 is a diagram showing a natural image and a color distribution of a building material pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input scanner 2 Storage device 3 Output scanner 4 Control device 5 Image processing device 51 Special color vector selection means 52 Special color component calculation means 53 Auxiliary color component calculation means

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideki Murota 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Ichiharu Hashizume 1-chome, Ichigaya-cho, Shinjuku-ku, Tokyo No. 1-1 Inside Dai Nippon Printing Co., Ltd. (72) Inventor Hiroshi Sawamura 1-1-1, Ichigaya Kagamachi, Shinjuku-ku, Tokyo Inside (72) Chikako Ohara Inventor Chikako Ichigaya-cho, Shinjuku-ku, Tokyo 1-1-1 Dai Nippon Printing Co., Ltd. (72) Inventor Yu Okamoto 1-1-1, Ichigaya Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (72) Inventor Yoshio Sukekawa Miyoshi Iruma-gun, Saitama 331, Takemazawa, Machi, Japan, Japan, Total Process Building Materials (56) References JP-A-2-26183 (JP, A) JP-A-2-1351 (JP, A) (58) Fields surveyed (Int .Cl. ⁷ , DB name) H04N 1/60 B41F 31/02 G03F 3/08 G06T 1/00 510 H04N 1/46

Claims (1)

(57) [Claims] 1. A special color vector selecting means for selecting a color vector with the highest frequency to obtain a special color vector (Uc, Um, Uy) based on each color density of color separation data represented by CMYK or CMY, Special color component calculation means for calculating a special color component (u) of the special color vector for each pixel of the color separation data under a constraint condition not exceeding each color density of the color separation data; By subtracting each color density of the separation data with the density of the special color represented by the special color component (u), the auxiliary color components (c, m,
An image processing apparatus comprising: an auxiliary color component calculation unit configured to calculate y).