JPH0518510B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color separation method for an apparatus for creating a film original plate for a region of a printed matter having a constant color, that is, a so-called plain mesh area.

(Prior art) There are many plain mesh parts in color printed matter, but the plate-making process for these plain mesh parts is carried out in a special process that is different from the plate-making process for general color parts, so-called tone products. . The conventional process will be explained below based on the drawings.

FIG. 8 shows an example of a printed matter made up of plain mesh portions. In the figure, a printed matter 50 is composed of a person 51, a mark 52, and a character part 53, and includes areas A1, A2, areas B1 to B6, and an area C.
1. The regions D1 to D3, the region E1, the outline S and the character W are each a constant color. The plate making of such a printed matter 50 is performed as follows.

First, a block copy 60 as shown in FIG. 9 is created. This is a drawing of only the outline appearing in the printed matter 50 shown in FIG. Based on this block 60, a color instruction sheet 61 as shown in FIG. 10 is created. In this color instruction sheet 61, a rough outline corresponding to the outline drawn on the block copy 60 is drawn,
The areas A to E surrounded by this rough outline are designated with a color as shown in the figure, and are painted with a color close to the designated color using a colored pencil or the like. Here, Y10, M50, and C20 of area A are the halftone area ratio (hereinafter referred to as "halftone %") of the yellow plate when creating a separated plate, and the halftone dot area ratio of the magenta plate is 10%.
50%, cyan version halftone percentage is 20%, black version halftone percentage
indicates that it will be 0%.

Next, the printing plate 60 shown in FIG. 9 is photographed with a camera, and a positive 71 and a negative 72 as shown in FIGS. 11a and 11b are created. The positive 71 is used to create masks corresponding to areas A to E shown in the color instruction sheet 61. The mask is made by laminating a colorless and transparent base film and a light-shielding film, and the light-shielding film can be easily peeled off from the base film.
Light can only pass through the area where the light-shielding film is removed. Therefore, a desired mask can be created by overlapping the positive 71 and the mask and cutting and peeling off the light shielding film along the outline of the positive 71.

FIGS. 12a, b, c, d, and e show the prepared masks, and the areas without diagonal lines are the parts where the light-shielding film has been peeled off. In the figure, mask 81
-85 correspond to the above-mentioned areas A to E, respectively. That is, the mask 81 hides areas other than areas A1 and A2 of the printed material 50 shown in FIG. 6, the mask 82 hides areas other than areas B1 to B6 of the printed material 50,
3 hides areas other than the area C1 of the printed matter 50, the mask 84 hides areas other than areas D1 to D3 of the printed matter 50, and the mask 85 hides areas other than the area E1 of the printed matter 50.

Next, a film original plate for each color is created using a transparent film in which halftone dots are uniformly provided at a predetermined halftone percentage (hereinafter referred to as "flat dot") and the masks 81 to 85. This is done by overlapping a mask and a screen screen and printing them on the film original plate, thereby forming halftone dots only in the desired portions of the film original plate.

FIG. 13 shows an outline of the process from the block copy 60 to the creation of the printed matter 50, 91,...
92, 93, 94, 95, 96 are flat nets, and the net percentages are 100%, 20%, 10%, 50%, 30%, respectively.
8%. Note that these various types of flat nets are prepared in advance. As shown in the figure, a positive 71 and a negative 72 are created from the master 60, and masks 81 to 85 are created from the positive 71, as described above.

Here, a method for creating the yellow plate 41 will be explained.
3, 84 and flat nets 91, 92, 93 are used.
First, the mask 81 and the flat mesh 93 are overlapped and printed on a film original plate to form a 10% halftone dot in the area A.
Next, the mask 82 and the flat screen 92 are overlapped and baked,
Furthermore, the mask 83 and the flat screen 92 are overlapped and printed, and finally the mask 84 and the flat screen 91 are overlapped and printed to each area B, C, and D of the same film original plate.
%, 20% 100% halftone dots are formed and yellow plate 41
is created. Similarly, masks 81, 82,
Magenta version 4 from 83 and flat mesh 94, 95, 93
2 is the mask 81, 82, 83, , 85 and the flat screen 9
A cyan plate 43 is created from 2, 93, and 96.

In addition, the black plate 44 is a black plate 60 shown in FIG.
Since it is composed only of the contour lines drawn on the screen, no mask is used, and it is created from the negative 72 and the flat dot 91 shown in FIG. 11b. That is, by overlapping the negative 72 and the flat mesh 91 and printing them on the original film, 100% halftone dots are formed in the above contour line,
Black version 4 is created.

Printing plates are created from the yellow plate 41, magenta plate 42, cyan plate 43, and black plate 44 thus created, and printed matter 50 is created by overprinting using ink and paper.

(Problems with the prior art) As mentioned above, the conventional plate-making process for the plain screen area is a complicated process using various masks and flat screens, and is all done by hand. Not only does it take a long time to create a mask, but it also tends to cause errors in pattern position during mask creation and overprinting, making it difficult to obtain the desired print. It was quite noticeable. As a means to solve such problems, a line image drawn on a document is read, the obtained image data is divided, and divided images of the line image are displayed on a display device, and the displayed divided images are After performing color separation processing that specifies the proportions of yellow, magenta, cyan, and black in each area separated by the outline of the line image and the border of the divided image, the divided image data is combined. An apparatus is conceivable that creates a film master for each color based on the color separation data obtained in the color separation process. In this case, the reason why the image data of the original is divided and displayed is because the number of display pixels in a normal display device is not so large that the entire image of the original cannot be displayed on the screen at once.

However, in such devices, color separation processing is performed with the line image of the original divided.
One continuous area on the manuscript is divided into multiple areas, and color separation processing is performed on these divided areas, which not only increases the number of color instructions during color separation processing operations, but also makes it easy to make mistakes in color instructions. However, a problem has arisen in that color separation processing cannot necessarily be performed efficiently.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems. It uses a computer to specify colors for divided images of a document, and directly creates film masters for each color, thereby improving the conventional method. In an apparatus that aims to improve the efficiency of the plate-making process for the plain mesh portion by eliminating the manual process of creating a mask and printing the plain mesh onto the film original plate, a part of the color separation processing operation for the above-mentioned divided images is automated, The purpose of this invention is to provide a method for efficiently performing color separation processing.

(Summary of the Invention) To achieve this object, the present invention reads a line image drawn on a document, divides the obtained image data, and displays divided images of the line image on a display device,
After performing color separation processing on the displayed divided image to specify the proportions of yellow, magenta, cyan, and black in each area separated by the outline of the line image and the boundary line of the divided image, the divided image is divided. In the device for creating a film original for each color based on the color separation data obtained by the color separation process by combining the image data obtained by the color separation process, the boundary line of each region of the divided image displayed on the display device is provided. We provide a color separation method for plain mesh in which the color separation processing of the area including the color separation processing is performed based on the color separation data of the boundary line of the divided image for which the color separation processing has already been completed.

(Function) In the present invention, a line image drawn on a document is divided and displayed on a display device, and for the displayed divided image, the area including the division boundary line has already been subjected to color separation processing. Color separation processing is automatically performed based on the color separation data of the boundary line of the completed divided image, and color separation processing is performed for other areas based on the newly specified proportions of yellow, magenta, cyan, and black. After this, the divided image data are combined, and a film original for each color is created based on the color separation data obtained in the color separation process.

(Example) Examples of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an example of an apparatus for carrying out the method of the present invention. In the figure, a scanner 1 reads images drawn on a document, and is connected to a computer 3 via an interface 2. Connected to this computer 3 are an external storage device 4 that mainly stores image data captured by the scanner 1, and a floppy disk device 7. Reference numeral 6 denotes an output scanner for reading image data stored in the external storage device 4 and outputting it to a film original processed by the computer 3, and is connected to the computer 3 via an interface 5. Reference numeral 10 denotes a color separation device, which is composed of a computer 11, a display 12 connected to the computer 11, a tablet 14 for inputting position data, and a floppy disk device 15. Further, the computer 3 and the computer 11 are connected through a communication line 18.

Next, the operation of the above device will be explained. Here, the printed matter printed using the film original plate created by the above-mentioned apparatus is the printed matter 50 shown in FIG. 8 described in the prior art, and the printing material 60 shown in FIG. 9 and the color instruction sheet shown in FIG. 10 are prepared in advance. shall be prepared.

First, the block 60 is set at a predetermined position on the scanner 1, and the scanning head of the scanner 1 is scanned to capture image data of the outline drawn on the block 60.
This image data is stored in the memory of the computer 3 via the interface 2. In this embodiment, the pixel density of the image data captured by scanner 1 is 18
The pixel density is 1 mm/mm, which is considerably lower than the pixel density of the original film, but this is to reduce the amount of image data. Data stored in the memory of the computer 3 can be read out, and after predetermined processing is performed, it is stored in the external storage device 4 or a floppy disk set in the floppy disk device 7. Note that the pixel density captured by the scanner 1 is not limited to the above example, and may be about 9 lines/mm for printed matter that does not require image precision.

FIG. 2 is a floppy disk showing the processing of image data captured by the scanner 1. In the figure, when a start signal is given by operating a keyboard or the like connected to a computer 3, image data is input into a scanner at step S1, and the captured image data is binarized and stored in the computer's memory at step S2. is stored in This stored image data is read out several lines at a time, and dust removal processing is performed at step S3. Dust removal processing is a process in which pixels smaller than a few pixels are regarded as dust and are automatically removed. Next, the image data is thinned out in S4, and the pixel density is reduced to 9 lines/mm. This is to facilitate subsequent image processing and operator operations. Further, if the pixel density of the image data taken in by the scanner in step 1 is 9 lines/mm, the thinning process in step 4 is not necessary. After this, the image data is divided into S5. The image data is divided into several parts by this division process, and in this embodiment, as shown in FIG.
It is divided into four parts: 2, 13, and 14. The division process is carried out because there is a limit to the number of pixels that can be displayed on the display 12 of the color separation device 10 shown in FIG. It is something that can be done. Next, image data is compressed in S6. This data compression is performed by replacing one line of the binarized image data with address data of points that change from white to black or from black to white. The data compressed in this way is stored in the external storage device 4 or the floppy disk in the floppy disk device 7.
7.

Next, the operation of the color separation device 10 will be explained.
Since the computer 11 of the color separation device 10 is capable of receiving image data from the floppy disk device 15 or the communication line 18, the case where data is taken from the floppy disk device 15 will be described first.

FIG. 4 is a flowchart showing the processing of image data in the color separation device 10.

First, the tablet 14 is operated to give a start signal, and the image data stored on the floppy disk set in the floppy disk device 15 is read out (S10) and displayed on the display 12 (S11).

FIGS. 5a, b, c, and d show images displayed on the display 12, and the images are displayed divided into 11, 12, 13, and 14 shown in FIG. In the figure, T is the color scale, and X _a , X _b , X _c , X _d , Y _a , Y _b , Y _c , and Y _d are the boundaries of the divided images, and these boundaries are the same as those on the display 12. is not displayed.

Here, in order to operate the color separation device 10, it is necessary to create a color scale T in advance, and a color table is used to create the color scale T, so the color table will be explained first. .

FIG. 6 shows a color table used in this embodiment. In the figure, Y stands for yellow.
M stands for magenta, C stands for cyan, and K stands for black. The color table 30 extracts only the halftone percentage of each color entered for each area of the picture in the color instruction sheet 61 shown in FIG. 10, and sequentially assigns color numbers to those with different values. Created by tabulating. The color numbers in the color table 30 and the dot percentage data for each color are stored on the tablet 14 or computer 1.
computer 11 from the keyboard connected to
and stored on the floppy disk in the floppy disk device 15.

Next, a color scale T is created. The color scale T allows 16 colors to be selected from the 512 colors that can be displayed on the display 12. Display of 16 colors is performed by representing each pixel data with 4 bits using 4 image planes, and a color close to the color displayed in the color instruction sheet 61 shown in Fig. 10 is selected. A color number of the color table 30 is assigned to the color table 30. Note that since such color selection is a known technique, detailed explanation will be omitted. In this embodiment, as shown in FIG.
Since different colors are used, t1, t2, t3,
Five types of color bands t4 and t5 are displayed on the color scale T. Furthermore, since black, which is used as the color of the outline, is normally used for any picture, it is always displayed in the color band t0 at the lower right corner of the color scale T. And these color bands t1, t2, t3, t4,
Color numbers 1, 2, 3, 4, 5, and 6 are assigned to t0, respectively.

In step 11 of FIG. 4, pixel display on the display 12 is first performed for the image 11 as shown in FIG. 5a. Next, it is determined whether or not to modify the displayed image data, and step S1
2. If there is a correction, select the correction number S13.

If modification No. 1 is selected, a pattern modification process is performed in step S14. The picture correction process is done on display 12.
This is a process that supplements the missing parts or erases unnecessary lines when the outline of the image displayed on the image is missing or there are unnecessary lines. In this process, first operate the tablet 14 to select a desired color band from the color scale T, then use the tablet 14 to input the position data of the missing part, and then select the selected color for the missing part. This is done by supplementing with . In this example, all the contour lines are black, so the color scale T
What is necessary is to select the color band t0. Furthermore, in order to erase unnecessary lines, a colorless color band (not shown) may be selected from the color scale T, and the same operation as described above for capturing the missing portion may be performed.

Next, if modification No. 2 is selected, bank creation processing is performed in S15. The bank creation process is a process in which the outline of the image on the display 12 is originally missing, but when this missing part also becomes a color boundary, new data for the missing part is created, Although it is not necessary for image 11,
Specifically, the data of the broken line portion L is created for the image 13 shown in FIG. 5c. The creation of data for this broken line portion L is performed in the same manner as the pattern correction process described above. That is, a color band is selected from the color scale T by operating the tablet 14, and in this case, the color band t5 is selected. Then,
By inputting the position data of L using the tablet 14, the broken line portion L is created in the color t5, and the creation of data for this broken line portion L is completed.

Next, when modification No. 3 is selected, hit rule processing is performed (S16). S1 where hit rule processing is performed
6. Hit rule processing is a process that converts this outline into color boundary data, since although it is displayed as an outline on the display 12, it is actually just a color boundary rather than an outline. Although it is not necessary for 11, specifically, for images 13 and 14 shown in FIG. The data conversion of the dashed-dotted line portion M is also performed in the same manner as the pattern correction processing and bank creation processing described above. That is, the user operates the tablet 14 to select a color band from the color skate T. In this case, since the color of the dashed-dotted line portion M is the same color as the area C1, the color band t3 is selected from the color scale T. Thereafter, by operating the tablet 14 to create the dashed-dotted line portion M in the color of the color band t3, the conversion of the data of the dashed-dotted line portion M is completed.

When any one of the above-mentioned pattern correction processing, bank creation processing, and hit rule processing is performed, step 17 is performed.
A judgment is made as to whether or not the process has ended, and if the process has not ended, the process returns to step 13, and steps 14 and 1 are performed.
Either process 5 or 16 is performed. In this way, the areas a1 and a of the image 11 shown in FIG.
2, b1, b4, b5, b6, d1, d4, d
When the boundaries of step 5 are completed, that is, when the creation of data indicating color areas is completed, the next color separation process is performed in S18.

The color separation process is performed by operating the tablet 14, selecting a desired color band from the color scale T, and filling each area of the picture with the color of the selected color band. That is, regarding the area a1 of the image 11, first operate the tablet 14 to specify the area a1, and then operate the tablet 14 to specify the color band t1 of the color scale T. Filled with color. Similarly, in the area a2, the color of the color band t1 is the same as that of the areas b1, b4,
b5, b6 are the colors of color band t2, areas d1, d4, d
5 is painted with the color of color band t4. When the color separation process for the image 11 is completed in this way, the color numbers assigned to the color bands painted in each area are stored as color separation data in the floppy disk in the floppy disk device 15. S19.

Similarly, the processing from step 10 to step 19 is performed for images 12, 13, and 14, and the areas a1, a2, b1, b2, b
3, b4, b5, b6, c1, d1, d2, d
Color separation data for all of 3, d4, d5, and e1 are stored on the floppy disk.

Here, in the color separation processing in step 18, the operation of filling each area displayed on the display 12 with a desired color is to fill in the color band data of the boundary line of the image that has already been subjected to the color separation processing to the image displayed on the display 12. This is done automatically without operating the tablet 14. That is, regarding the image 12 shown in FIG. 5b, the color band data of the pixels on the boundary line Y _a of the image 11 shown in FIG _. Areas a1, a2, b1, of image 12
Color band data of color scale T is given to b5, b6, d1, and d4, and these areas are automatically painted with a desired color. Therefore, for the image I2, it is only necessary to operate the tablet 14 to provide color band data of the color scale T only to regions b2, b3, and d2.

Similarly, for the boundary line X _c of image 13, the color band data of the boundary line X _a of image I1 is given,
For the boundaries X _d and Y _d of the image I4, the color band data of the boundary line X _b of the image I2 and the image Y _c are given, and a part of the area of the images I3 and I4 is automatically painted with a desired color. Then, areas that have not been colored yet are colored by operating the tablet 14, and the color separation process is completed.

The color separation process described above was performed by filling each area of the picture on the display 12 with the desired color using the color scale T. For each area, one area may be specified by operating the tablet 14, and the color number of the color scale 30 for the specified area may be directly input by operating the tablet 14 or the like.

The floppy disk on which the color separation data is stored in this way is set in the floppy disk device 7 connected to the computer 3, and the computer 3 transfers the data stored on the floppy disk to the output scanner 6. converted to data.

FIG. 7 is a flowchart showing the process of outputting film originals of each color from the scanner 6 based on the data stored on the floppy disk.

First, a start signal is given by operating a keyboard or the like connected to the computer 3, and data stored on the floppy disk is read out from the floppy disk device 7 at step S21. Next, the images I1, I2, I3, and I4 stored separately on the floppy disk are combined.
S22.

In step S23, interpolation processing is performed on the combined image data. The interpolation process is a process of converting the pixel density of the image data to the pixel density for the film original, and in this embodiment, the image data of 9 lines/mm is interpolated to become the image data of 72 lines/mm. Note that the pixel density after interpolation is not limited to the above example.
It is sufficient if the number is about 30 lines/mm or more. Smoothing processing is performed on the interpolated image data.
24. The smoothing process removes the roughness of the image outline caused by the interpolation process in step 23. This smoothing process smoothes the image outline, and the image is smoothed as shown in FIG. 9.
It will be in a state close to the outline of the picture drawn at 0.

Next, in S25, double processing is performed. Double processing is a process that overlaps the boundaries between colors.
In the case of the printed matter 50 shown in FIG. 8, the above area a
1, a2, b1, b2, b3, b4, b5, b
6, d1, d2, d3, d4, d5, and e1 may be made slightly thicker so that they overlap with the contour line.

After this, data conversion processing is performed in S21.

The data conversion process begins at step 18 shown in FIG.
Areas a1, a2, b1, input by color separation processing
b2, b3, b4, b5, b6, c1, d1, d
2, d3, d4, d5, e1 color number data,
This converts the data into halftone percentage data for yellow, magenta, cyan, and black.The color number and halftone percentage data for each color are read out from the color table 30 stored on the floppy disk, and the color number data is converted into Y, M. , C, K into dot % data. By this, yellow,
This means that film original data for each color of magenta, cyan, and black has been created.

Next, a case will be described in which the computer 11 shown in FIG. 1 takes in image data via the communication line 18 and performs color separation processing. In this case, data storage in step 7 of FIG. 2 is performed in the external storage device 4 shown in FIG.

First, in step 10 of FIG.
1 reads image data stored in the external storage device 4 via the communication line 18. Step 1
The processing from step 1 to step 18 is the same as when data is taken in from the floppy disk device 15. The color separation data created in step 18 is then sent to the computer 3 via the communication line 18 in step 19, and stored in the external storage device 4. At this time, the color numbers of the color table 30 and the dot % data of each color are also stored in the external storage device 4.

Thereafter, in step 21 of FIG. 7, the computer 3 reads data stored in the external storage device 4. The processing from step 22 to step 26 is the same as when data is taken in from the floppy disk device 7.

The film original data created in this way is sent to the data bus shown in FIG. 1, and output via the interface 55 to the film original set on the scanner 6, so that desired halftone dots are formed for each color. The original film is created.
22.

(Effects of the Invention) As described above, in the present invention, a line image drawn on a document is read, the obtained image data is divided, the divided images of the line image are displayed on a display device, and the displayed After performing color separation processing on the divided image to specify the proportions of yellow, magenta, cyan, and black in each area separated by the outline of the line image and the boundary line of the divided image, the divided image data is processed. In a device that creates a film original for each color based on the color separation data obtained by combining the color separation processing, for the divided image displayed on the display device, for the area including the dividing boundary line, , color separation processing is automatically performed based on the color separation data of the boundary line of the divided image for which color separation processing has already been completed, and for other areas, the newly specified proportions of yellow, magenta, cyan, and block are used. Since the color separation process is performed based on the color separation process, it is possible to greatly improve the efficiency of the plate-making process for plain mesh areas, which was previously done entirely by hand.
It is possible to reduce the number of color instructions in the color separation processing operation, reduce errors in color instruction, and achieve the effect that the color separation processing operation, which tends to be complicated, can be performed extremely efficiently.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of an apparatus for implementing the method of the present invention, FIG. 2 is a flowchart showing processing of image data captured by the scanner 1 shown in FIG. 1, and FIG. Figure 3 shows step 7 in Figure 2.
Fig. 4 is an explanatory diagram of image data stored in
A flowchart showing the processing of data in the color separation device 10 shown in the figure, FIG. 5 is the display 1 of FIG. 1.
Explanatory diagram showing an example of the image displayed on 2, No. 6
FIG. 7 is an explanatory diagram showing an example of a color table used in the color separation process in step 18 of FIG. 4, and FIG. 8th
The figure is an explanatory diagram showing an example of a plain mesh portion of a printed matter, FIG.
An explanatory diagram showing an example of a color instruction sheet used in the plate-making process of the printed matter 50 shown in the figure.
Explanatory diagrams of the positive and negative images taken with a camera of the block copy 60 shown in the figure, Figures 12 a, b, c, d, and e are the 8th
An explanatory diagram showing an example of a mask used when the printed matter 50 shown in the figure is created by a conventional plate-making process, and FIG. It is an explanatory diagram. 6... Output scanner, 7... Floppy disk device, 10... Color separation device, 15... Floppy disk device, 30... Color table, 50... Printed matter, 6
0...block print, 61...color instructions, 71...positive, 72...
Negative, 81, 82, 83, 84, 85...mask,
91, 92, 93, 94, 95, 96...Flat mesh.

Claims (1)

[Claims] 1. Read a line image drawn on a document, divide the obtained image data, display the divided images of the line image on a display device, and compare the outline and division of the line image with respect to the displayed divided images. After performing a color separation process that specifies the proportions of yellow, magenta, cyan, and black in each area divided by the image border, the divided image data is combined to create the color separation obtained by the color separation process. In a device that creates a film original for each color based on data, the color separation process for the area including the boundary line among the areas of the divided image displayed on the display device is performed by dividing the area that has already been subjected to the color separation process. A color separation method for plain mesh, characterized in that the color separation method is performed based on color separation data of image boundaries.