JPH02214862A - Monitor color adjusting circuit - Google Patents

Abstract

PURPOSE:To approximate the color reproducibility of a color monitor to that of printed matter by converting a primary color signal of a subtractive mixed color, outputted by a gradation and color tone adjusting means, into a primary color signal of an additive mixed color and supplying it to the color monitor. CONSTITUTION:The monitor color adjusting circuit is provided with a process circuit 12 which adjusts a Y, an M, and a C signal outputted from a BGR/YMC converting circuit 10, which inputs a B, a G, and an R signal to be supplied to the color monitor and converts them into the Y, M, and C signals, and the gradation characteristic curve of the K signal composed of them, corresponding to that of printed matter and a matrix circuit 16 which converts the Y, M, C and K signals outputted by the process circuit 12 into the B, G, and R signal and supplies them to the color monitor 20. Thus, gradations and color tone are adjusted and the signals are converted into color signals for display, which are then supplied to the color monitor 20, thereby approximating the color reproducibility of the color monitor to the color reproducibility of printed matter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monitor color adjustment circuit that approximates the color reproducibility of a color monitor to that of printed matter.

[Prior Art] Conventionally, in printing systems such as layout systems, design systems, and computer graphics, the finished state of printing has been simulated using a color monitor.

[Problems to be Solved by the Invention] Here, color monitors display color images by additive color mixture, while printed matter prints color images by subtractive color mixture, so the color reproducibility of color monitors is similar to that of printed matter. Better than. As a result, even though the simulated image has very vivid gradations and tones, when the simulated image is actually printed, the simulated color reproducibility is often not achieved, which causes inconvenience in the fields of plate making and printing. Ta.

This invention was made to deal with the above-mentioned circumstances,
The purpose is to provide a monitor color adjustment circuit that can approximate the color reproducibility of a color monitor to that of printed matter.

[Means for Solving the Problems] A monitor color adjustment circuit according to the present invention includes a BGR/YMC conversion circuit that manually converts B, G, and R signals to be supplied to a color monitor into Y, M, and C signals. , BGR/MMC
Y output from the conversion circuit.

A process circuit that adjusts the gradation characteristic curve of the M and C signals and the signal synthesized from them according to that of the printed matter, and a process circuit that adjusts the Y, M, C, and B, G, R signals output from the process circuit. It is equipped with a matrix circuit that converts the signal into a signal and supplies it to a color monitor.

[Function] According to the monitor color adjustment circuit according to the present invention, a color signal for display supplied to a color monitor is once converted into a color signal for printing, the gradation and color tone are adjusted in the signal, and then the color signal is converted again. Since the color is converted into display color No. 4M and then supplied to the color monitor, the color reproducibility of the color monitor can be approximated to the color reproducibility of printed matter.

[Embodiment] An embodiment of the monitor color adjustment circuit according to the present invention will be described below with reference to the drawings. FIG. 1 is its circuit diagram. Blue (B) to be processed in image processing systems for other printing applications, such as print simulation systems, computer graphics systems, and displayed on color monitors.
, green (G).

An additive primary color signal of red (R) is input to the BGR/YMC conversion circuit 10 . In other words, this B.

The G and R signals are image signals for displaying printed matter.

The BGR/MMC conversion circuit 10 first converts B and G signals.

Adjust the gain (GA I N) and pedestal level (PED) of R (No. 8), then invert the B, G, and R signals to make them complementary colors, which are used for printing such as yellow (Y), magenta (M),
A subtractive primary color signal of cyan (C) is generated. RGB
The output of the /YMC conversion circuit 10 is supplied to a process circuit 12 and a black plate synthesis circuit 14.

Black version synthesis circuit] 4 is NAM (Non Additive
eMixer (non-additive mixer) circuit 14
The minimum value of the input Y, M, and C signals is detected using a, and the minimum value signal is used as the black (K) signal. After the highlight level (HL) and shadow level (SD) of the K signal are adjusted, gamma correction (γ) is performed to determine the strength of the overall gradation. The signal output from the black plate synthesis circuit 14 is also supplied to the process circuit 12.

The process circuit 12 detects the highlight level (HL) and shadow level (SD) of the input Y, M, and CK signals.
and then highlight separation (H,S)
, middle separation (M.

Adjust the variable resistors 12a for Y, M, C, S), shadow separation (S,
The gradation characteristic curve of the image signal is controlled to a curve showing desired characteristics such as highlights, halftones, shadows, etc. This gradation control curve is determined in advance according to printing conditions. Thereby, the gradation characteristics and color tone characteristics of the image signal are corrected so as to represent the gradation characteristics and color tone characteristics of the actual printed matter. The Y, M, and C signals output from the process circuit 12 are input to the matrix circuit 16.

The matrix circuit 16 includes variable resistors that adjust the levels of white and black, Y components of primary color, secondary color, tertiary color, and quaternary color, M
Y-Y, Y-M, Y whose components and C components can be varied respectively.
-6a. A matrix circuit] 6 converts the Y, M, C, and signals into B, G, and H primary color signals for display on a monitor.

The B, G, and R signals output from the matrix circuit] 6 are supplied to a level conversion circuit 18, and after level adjustment, are supplied to a color monitor 20. As a result, BGR/Y
Even if a display image signal processed by an image processing system is input to the MC conversion circuit 10, the process circuit 12 and matrix circuit 16 convert the gradation characteristics and color tone characteristics of the display image signal into the gradation characteristics and tone characteristics of the printed matter. Since the color image is corrected to match the color tone characteristics, a color image having the color reproducibility of the actual printed matter is displayed on the color monitor 20. Therefore, the image processing system can simulate the color gradation of an actual printed matter.

[Effects of the Invention] As explained above, according to the monitor color adjustment circuit according to the present invention, the color signal for display supplied to the color monitor is once converted into the color signal for printing, and the gradation and color tone are adjusted in the signal. Since the color reproducibility of the displayed color image can be approximated to that of printed matter, this is effective when simulating printed matter using the displayed image.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of a monitor color adjustment circuit according to the present invention. ] 0... BGR/YMC conversion circuit, 12... Process circuit, 14... Black plate synthesis circuit, 16... Matrix circuit, 18... Level conversion circuit, 20... Color monitor. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] a converting means for generating a subtractive primary color signal by inputting an additive primary color signal; and a converting means for generating a subtractive primary color signal by inputting an additive primary color signal; A monitor color adjustment circuit comprising a gradation and color tone adjustment means for adjusting, and a means for converting a subtractive color mixture primary color signal output from the gradation and color tone adjustment means into an additive color mixture primary color signal and supplying the signal to a color monitor.