JPH02217854A - Printing simulation device - Google Patents

Abstract

PURPOSE:To color paper white and to enable simulation in an accurate finish state even at the time of printing of paper which is slightly yellowish and not purely white like newspaper by decreasing the gradations of a simulation image. CONSTITUTION:When the background of printed matter is not purely white, a white frame function is used to display a white frame on a color monitor 86 in paper white, and this white frame is colored matching the base of the printed matter. Thus, the highlight-side gradations of a color image signal are varied greatly to the shadow side to adjust white balance, thereby matching the white level of a display image with the color of the background of the printed matter. Consequently, the finish state of the printed matter can be simulated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a printing simulation device useful for determining color separation conditions for a color scanner, and particularly relates to simulation when printing on paper that is not pure white, such as newspaper. .

[Prior Art] Such a printing simulation device is connected to a color scanner, inputs an image signal read by the color scanner, and uses a color correction circuit equivalent to that of the color scanner to process the signal for each color component of printing. Perform various corrections,
Display the corrected color image. The operator determines whether the various correction amounts, that is, the color separation conditions, are appropriate while looking at the color tone of the displayed image, and determines the color separation conditions that will provide a preferable color tone.

[Problems to be Solved by the Invention] Here, the white balance of the color display section is set so that white paper is displayed white.
There is no problem when printing on pure white paper, but when printing on paper that has a slight yellowish tinge and is not pure white, such as newspapers for which color printing has become popular in recent years, it is important to check the accuracy of the finish. Simulation is not possible. That is,
Since reading by a color scanner does not take into account the color of the base, the color of the base in the simulation image is always displayed as pure white, which does not match the actual finished state.

This invention was made to deal with the above-mentioned circumstances,
The purpose is to provide a printing simulation device that can simulate the finished state of printed matter by considering the color of the base of the printed matter.

The printing simulation device according to the present invention can match the self-level of the displayed image with the color of the base of the printed material by adjusting the white balance by changing the gradation of the highlight side of the color image signal more than the shadow side. .

[Embodiment] An embodiment of the printing simulation apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration. The basic configuration of this embodiment is that a simulation unit 4 is connected to a color scanner. As the color scanner, an existing direct scanner (SG 60g, manufactured by Dainippon Screen Mfg. Co., Ltd.) or the like can be used. The simulation unit 4 is placed below or behind the color scanner. however,
Among them, a color monitor 86 and an operation panel 90 (described later) are separate, and the color monitor 86 is placed in a place where it can be easily seen, and the operation panel 90 is placed near the operation panel of the color scanner.

The configuration of a color scanner will be briefly explained. The color original 12 attached to the reading drum 10
The rotation of the drum 10 and the movement of the read head 14 in the axial direction of the drum 10 scan the image information. The reading head 14 is equipped with a photomultiplier as a photoelectric conversion element, and the obtained image signal is converted into B, G,
Output as an R image signal.

B, G, and R image signals output from the reading head 14 are subjected to current/voltage conversion by a current/voltage (C/V) converter 16, and are supplied to a calibration circuit 18 for level adjustment. The output signal of the calibration circuit 18 is logarithmically compressed by a logarithmic (LOG) amplifier 20 and then supplied to the simulation unit 4 and the color processing circuit 24.

A selector 22 is connected between the logarithmic amplifier 20 and the color process circuit 24. A first input terminal of the selector 22 is connected to the output of the logarithmic amplifier 20, and a second input terminal is connected to the output terminal of the simulation unit 4. The selector 22 selects one of the first and second human input signals and supplies it to the color process circuit 24 .

The color process circuit 24 performs color separation such as color correction and gradation correction for printing, and also includes a masking circuit and undercolor removal (
It consists of a UCR) circuit, a gradation correction circuit, a dot % display circuit, etc. The masking circuit performs so-called masking correction and converts the B, G, and R signals into yellow (Y), magenta (M), and cyan (C) signals. Undercolor removal circuit is basic 4 of printing
Y to print in the colors Y, M, C, K (black),
M.

Convert the C signal to Y, M, C, signals. The gradation correction circuit performs gradation correction such as highlight set, shadow set, middle separation, highlight separation, and shadow separation.

These correction amounts and correction amounts (disassembly conditions) can be determined using the operation panel 90.
The color separation conditions can be adjusted appropriately by operating the operating members, and thereby the color separation conditions matching the desired color tone can be set.

After the color is corrected and corrected in the color processing circuit 24, the Y, M, C, image signals are converted into inverse logarithms (LOG'
) After being logarithmically expanded by the amplifier 28, it is supplied to the channel selector 30. Note that the output of the color process circuit 24 is also supplied to the simulation unit 26.

The channel selector 30 selects which color signal to output depending on whether the separation film is exposed for four colors at the same time or for one color at a time. The output of the channel selector 30 is converted into a digital signal by an analog/digital (A/D) converter 32 and then supplied to a dot generator 34.

The dot generator 34 takes into account the magnification of the color separation film 40 with respect to the color original 12 and converts the image signal into a halftone signal for recording as halftone dots. Exposure head 3
6 exposes the color separation film 40 on the recording drum 38 in accordance with the halftone dot signal whose magnification is controlled. By developing this color separation film 40, color separation plates are created.

Note that the connection location between the color scanner and the simulation unit 4 is not limited to the above example.

That is, in the above explanation, the output signal of the logarithmic amplifier 20 (
Since the input signal to the color process circuit 24 is supplied to the simulation unit 4, the signal from the simulation unit 4 is input to the color process circuit 24 via the selector 22. However, the selector 22 is connected between the calibration circuit 18 and the logarithmic amplifier 20, and the output of the calibration circuit 18 (the human input signal to the logarithmic amplifier 20) is supplied to the simulation unit 4, and the signal from the simulation unit 4 is It may also be supplied to a logarithmic amplifier 20. In this case, the output signal of the antilogarithmic amplifier 28 is also supplied to the simulation unit 4.

FIG. 2 is a block diagram of the simulation unit 4. The B, G, and R signals output from the logarithmic amplifier 20 and supplied to the first input terminal of the selector 22 are connected to an interface (1/ F) Written via the circuit 58 to the first frame memory 62 consisting of a semiconductor memory. The level adjuster converts the voltage level of the image signal. The voltage level of the image signal in the color scanner varies depending on the type of scan t, and in the simulation unit 4, it is 0.7 Vpp, which is common for video signals, so level conversion is necessary. The averaging circuit is a kind of low-pass filter circuit, which averages the manually input image signal to make it a somewhat smooth signal, and controls it in accordance with the sampling frequency in A/D conversion.

The frame memory 62 is 512 x 512 (uniform *) x 3 (color) per screen, and each ii! ii element in 8 bits (256
It has a capacity to store image signals expressed in 11 degree steps for two sides.

When the frame memory 62 is read, the horizontal address and the vertical address are exchanged, and the image can be rotated by 90 degrees left and right. The frame memory 62 also has a negative/positive conversion function. Negative/positive conversion is performed only when the color original M12 is a negative original, and the density error during conversion is within ±1%.

Also, for negative/positive conversion, select one of the four color channels.
This selection can be preset.

The signal read from the frame memory 62 is transmitted to the I/F circuit 5
8. The signal is supplied to the color processing circuit 24 via the second input terminal of the selector 22, and this signal is color-separated.

A color scanner reads one image on a drum 10.
It takes about 20 seconds to read at 512 rotations, and the frequency band of the color processing circuit 24 is designed to be about 20 KHz. Therefore, writing to the frame memory 62 is 20
In order to match the frequency band of the color processing circuit 24, one image signal is read out in about 2 seconds.

The output of the frame memory 62 is an I/
The signal is also supplied to the hard disk memory 68 via the F circuit 66. The hard disk memory 68 is a cassette type and has approximately 2
It has a storage capacity of 0MB and can store image signals for 18 screens, one of which stores images from the other 16 screens at 1/16
This is a headline image that has been reduced (thinned out).

On the other hand, the output signals Y, M, and C of the color process circuit 24 input to the simulation unit 4 (after color correction) are written to the second frame memory 76 consisting of a semiconductor memory via the I/F circuit 72. be included. 1/F circuit 72
Similarly to the I/F circuit 58, there is a level adjuster, an averaging circuit,
It has an A/D converter etc.

The frame memory 76 has 512×512 pixels (
It has a capacity to store two screens worth of image signals expressed by 8 bits (256 density gradations) for each pixel, with 4 pixels (pixels) x 4 (colors). The frame memory 76 is also connected to the hard disk memory 68 via the I/F circuit 66, with Y, M, C, K
No. 11 can be written to the hard disk memory 68 and read from the hard disk memory 68.

The frame memory 76 has an image enlargement function (×2°×4),
It has a reversing function (up and down, left and right), a two-image comparison display function, and a non-interlaced output function.

According to the enlargement function, it is possible to display the area of the enlarged part and to move the area. Furthermore, the display area after enlargement can also be moved. The reversing function is a function of reversing an image vertically and horizontally like a mirror. What is the 2-image comparison display function?
This is a function that displays half of each image on the left and right or top and bottom of one screen, and allows you to compare the image before and after color correction, or to display a specific part of two images (for example, the background). ) is used to compare two images after color correction to unify the colors. Comparison of these two images shows that the overall color tone, gradation, etc. of printed matter based on multiple color originals can be determined.
can be compared and unified.

Furthermore, by controlling the readout address, it is possible to scroll the two-image comparison display screen and view each image in its entirety.

The signal read from frame memory 76 is supplied to color processing circuit 81 via D/A converter 80. D
The /A converter 80 has a flashing circuit, a dot % display circuit, a color separation display circuit, a gamma correction circuit, a white clip circuit, and a color trace circuit. The flushing circuits are Y, M, and C.

To flash pixels having a level equal to or higher than a highlight set level in a K image. This highlight set level is variable for each color. When viewing each Y, M, and C separated image, flashing occurs in each color when each pixel level exceeds the highlight set level, and when viewing a three-color composite image, gray (Y).

Flashing is performed at approximately 40% of the halftone dots of each version of M and C.

K requires an on/off switch, and when it is on, flushing occurs at about 40% of the halftone dots. The dot % display circuit displays a movable "+" mark on the screen of the color monitor 86 and outputs the DC level of YM, C, measured at the center thereof. The white frame circuit displays a frame of the paper base color (paper white) outside the printed matter displayed on the color monitor 86.

The color separation display circuit displays various combinations of pixels of each color of Y, M, and C. Gamma correction envelopes are Y and M.

Each color can be adjusted independently, and the gamma characteristics of plate making and printing can be corrected. Additionally, four types of presets are possible.

The color trace circuit memorizes the color of a specific pixel (level of four color signals) of a specific page of the document, and displays that color along with the stain correction image of subsequent documents as necessary. It is a circuit. This ensures that the same portions of a series of color originals are printed in the same color. When using a color photo as an original, the colors of the original may be out of sync, but this function can correct this. The color tracing function is used for color matching between multiple documents, such as back color matching of product colors or product color matching (automobiles, home appliances, furniture, etc.).

For example, if there are 10 color originals and the background color must be unified, the first original must be finished in an appropriate tone, and one pixel within the 2e*2cm square color patch on the back must be Latch the signal. When simulating the next manuscript, the color patch part is read from the data latch instead of the simulation image.
Insert and display the output data. Then, by manipulating the color correction amount of the color processing circuit 24 of the color scanner so that the color tone of the background matches the color tone of this color patch, the color of the background can be unified in a plurality of color documents.

The output of the color process circuit 81 is supplied to a 5-monitor circuit 84 via a matrix circuit 82. The matrix circuit 82 receives Y and M signals for printing.

The image signals of C and B are television signals.

This is a circuit for converting into an R image signal, and a circuit for converting the amount of ink into the brightness of B, G, and H color beams.

The monitor circuit 84 performs curve correction (nonlinear correction that occurs in a color monitor), peaking correction, white frame level adjustment, and dark level :A adjustment. The level adjustment of the white frame is performed in order to match the white color of the paper outside the simulation image on the color monitor 86 to the color of the base of the actual printed matter. B and G output from the monitor circuit 84.

The R image signal is input to the color monitor 86, and a printed image is displayed (simulated) when separated plates obtained under the current color separation conditions are printed. Here, the color monitor 86 is preferably a 20-inch non-interlaced monitor with good white uniformity.

The simulation unit 4 further includes an operation panel 90 for giving various commands and a timing generator 92 for giving various operation timings.

The operation panel 90 is in scan mode; film size (3
5--16X7cm+, 4X5 inches, 8x10 inches); Channel selection; Rotation/reversal; Color separation display (Y,
Fwl, C, K); Dot % display (joystick, on/off); Enlarge (x2.x4, position);
White frame (color, position); 2-image comparison (switch, scroll volume); Flashing (level setting, flashing for each color, YIC and YMCK selection possible): Image recording (from frame memory to hard disk memory): Image playback (For RGB images, hard disk memory 68 - frame memory 62 -> color process circuit 24 - frame memory 76; for YMCK images, hard disk memory 68 -> frame memory 78); Multi-screen display; Image transfer (from frame memory to frame memory) etc. will be issued.

Here, the scan mode is the operating mode of the read head 14, and there are three modes: quick, normal, and quick. When the quick scan switch is off, the read mode is the normal mode. The normal scan mode is specified not during simulation but when exposing an actual color separation plate, and at this time also, the image signal is thinned out and displayed on the color monitor 86.The stop switch is closed at 7 of the quick scan. Then, the color scanner also stops, but the stop switch is closed during fine scanning, so the color scanner does not stop.

The input/output signals of the timing generator 92 are as follows. Input signals include a color separation start signal, encoder pulse, start, cropping, drum size, magnification, screen line count, dark, document size, rotation, inversion, and enlargement. The output signals consist of a mode signal, a horizontal feed signal, a synchronization signal, a frame memory control signal, and a hard disk control signal.

A white frame level adjustment circuit within the monitor circuit 84 is shown in FIG. B, G, and H image signals are sent to a Bacolor controller (IC) 100. A color control signal from an operation polyneum 102 within the operation panel 90 is also manually input to the vapor color controller 100. The vapor color controller 100 colors the simulation image according to the coloring properties of the base of the printed matter, and inputs the input signal (4th line) for each color component signal as shown by the ri1 line in FIG.
The level of (solid line in the figure) is increased and the gradation is lowered. Here, the gradation is changed more greatly on the highlight side (the brighter side of the picture) than on the shadow side (the darker side of the picture), and moreover, it is changed non-linearly. This is because when simulating white paper, the highlight side is more affected, and the shadow side is less affected. How the gradation is reduced is determined by the level of the control signal.

Therefore, by determining the level of the control signal according to the color of the base of the printed matter, the simulation image can be colored according to the color of the base. This makes it possible to accurately simulate the finished state even when printing on paper that is not pure white but has a slight tint to it. Note that the control signal may be generated not only from the operation volume 102 but also from the preset resistor 104. Here, four preset resistors 104 are provided, and any one of their outputs is selected via a channel selector 106 and applied to the control signal input terminal of the vapor color controller 100 i5. That is, when the color of the background is known in advance, the resistance value of the preset resistor 104 is adjusted to :A so that a control signal of a level corresponding to the color can be generated. This preset allows up to four colors.

Next, a simulation method using the printing simulation apparatus according to this embodiment will be explained. The operator looks at the color original 12 and sets the color separation conditions deemed preferable to the masking circuit, undercolor removal circuit, gradation correction circuit, etc. in the color process circuit 24. Then, the color original 12 is attached to the reading drum 10, and rough reading is performed to simulate a printed image. For example, for a 4 x 5 inch film, the magnification of the color scanner should be set to 32% (0.
, 32 times), the entire screen of the color original 12 is scanned with 512 scanning lines, and the color original 12 is
image signals are read. This image signal is input to the simulation unit 4 via the I/F circuit 58,
It is stored in the frame memory 62. At this time, selector 2
2 is connected to the logarithmic amplifier 20 side. At the same time, the image signal is color-corrected in the color processing circuit 24 and then
It is manually input to the simulation unit 4 via the F circuit 72 and stored in the frame memory 76. A print image is simulated based on the output of the frame memory 76 and displayed on the color monitor 86.

Here, if the base of the printed material is not pure white, first, a white frame of paper white is displayed on the color monitor 86 using the white frame function, and this white frame is colored to match the base of the printed material. If the background color is preset, use the channel selector 106.
It is only necessary to select one of the preset resistors 104 using the .

If the color of the white frame does not match the color of the base of the printed material only by selecting the preset resistor 104, adjustment is made by operating the operation volume 102.

Thereafter, when this control signal level is fixed and the output signal of the frame memory 76 is supplied to the color monitor 86 via the vapor color controller 100, a simulation image colored according to the color of the base is displayed. If the simulated image has a desirable tone, the exposure drum 3
8, the color separation film 40 is attached to the color original 12.
Scan the image and perform color separation work (film exposure).

If the color tone of the simulation image is undesirable, adjust the correction amount of the color process circuit 24 to change the color separation conditions, connect the selector 22 to the simulation unit 4 side, and transfer the storage signal of the frame memory 62 to the I/O.
After supplying the color to the color processing circuit 24 in the color scanner via the F circuit 58 and performing color correction again, the I/F circuit 72
to the frame memory 76 and change the tone of the simulation image on the color monitor 86.

In this way, the color tone of the printed image under each color separation condition can be checked on the color monitor 86 without creating color separation plates. You can check the version.

[Effects of the Invention] As explained above, according to the present invention, by lowering the gradation of the simulation image, even when printing on paper that has a slight yellowish tinge and is not pure white, such as newspaper,
It is possible to color white paper and accurately simulate the finished state.

[Brief explanation of the drawing]

Figure 'N41 is a block diagram of an embodiment of the printing simulation apparatus according to the present invention, Figure 2 is a block diagram of a simulation unit of the embodiment, Figure 3 is a circuit diagram of the white frame level adjustment circuit in the monitor circuit, FIG. 4 is a diagram showing the characteristics of the white frame level adjustment circuit. 24...Color process circuit, 62.76...Frame memory, 8,2...Matrix circuit, 84...
Monitor circuit, 86... Color monitor, 100... Paper color controller, 104... Preset resistor. Applicant's agent Patent attorney Takehiko Suzue (Kuchiwa)

Claims (1)

[Claims] A printing simulation device that displays the printed state of a color document as a color image is equipped with a means for adjusting white balance by changing the gradation of the highlight side of the color image signal to a greater extent than the shadow side, thereby adjusting the white of the displayed image. A printing simulation device that matches the color of the base of printed matter.