JPS6352593A - Color correcting device for video printer - Google Patents

Abstract

PURPOSE:To operate the titled video printer in a way that the hue of a card copy and the hue on a monitor are always made coincident with the hue of an input signal by interposing a means correcting the color purity before memorization and interposing a correction means applying inverse conversion to the said correction between a memory output and an output to the monitor. CONSTITUTION:A converted Y and color difference signal are converted into three primary color signals R0, G0, B0 at an RGB matrix 3 of the next stage. Moreover, the correction in matching with the color characteristics of print is applied in a color correction matrix 4 of the next stage and the signals are converted into three primary color signals Rp, Gp and Bp for printing. The written signals R, G, B are fed to line print section 10 and a DAC 7. The signals are decoded into signals R0, G0, B0 proper for monitoring by the DAC 7 and then the inverse color correction matrix 8. Thus, the signals R0, G0, B0 equal to the input signals and the print signals are reproduced by the inverse color correction matrix 8 and the ink paper characteristic for the print.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a video printer that reproduces an image on paper from an Eirin signal, and relates to color correction suitable for optimal color tone expression both for printing on goods and for monitoring. .

[Conventional technology]

Conventional devices take into account the gamma characteristics of television cameras and film, and input The total gamma characteristics from the signal source to the hard copy were studied. However, no consideration was given to the purity of the reproduced colors of the film or the sensuality of the hard copies used.

[Problem that the invention seeks to solve]

The above conventional technology does not take into consideration the color purity of the film or ink when obtaining a hard copy, and the hue of the hard copy that accompanies this color purity. There was a moment when a discrepancy occurred.

It is an object of the present invention to eliminate the above-mentioned hue shift by 1, and also to simultaneously match the hue of the monitor output video of the memory image to the input signal.

[Means for solving problems]

The above purpose is to insert a means for correcting the color purity of the film or ink before it is stored in memory, to match the hue of the hard copy output, and also to match the hue deviation of the monitor image by inserting this correction means. This is achieved by inserting a correction means for the above correction and inverse transformation between the memory output and the output to the monitor.

[Effect]

The above ink correction means corrects the hue shift due to ink characteristics! T! I did it yesterday. At the same time, the inverse transform correction means operates to restore the corrected signal to its original state again. Thereby, the hue of the hard copy and the hue on the monitor can always be operated to match the hue of the input signal.

〔Example〕

The following is an example of the present invention? :Explained with reference to FIG. In the figure, 1 is a video signal input terminal, 2 is a luminance/color difference conversion means, 3 is an RGB matrix, 4 is a color correction matrix,
5 is an analog/digital conversion means (hereinafter abbreviated as ADC), 6 is an image memory means, 7 is a digital/analog conversion means (hereinafter abbreviated as DAC), 8 is a play-of-color correction matrix, 9 is an encoder, and 10 is a line print section. It is. Here, the line print section is connected to the signal selector 101. Line memory 102. Halftone control means 103. Thermal head 10
Consists of 4.

Next, the operation will be explained. The input video signal is separated into a luminance signal (Yffi signal) and a color signal in the luminance/color difference conversion means 2, and the color signal is demodulated to produce color difference signals (R-Y and B-Y
signals). The converted Y and color difference signals are converted into three primary color signals in the next stage RGB matrix 5.
Be converted to B. Further, in the next stage color correction matrix 4, correction is applied to match the color characteristics of the print, and the signals are converted into three primary color signals Rp, Gp, and Bp for printing.

The ADC 5 converts the signal into a digital signal, and the signal for one field or one frame is written into the image memory 6. The written digital R, G, B signals are
The data is read out in exactly the same manner as the write operation and sent to the line print unit 10 and DAC 7. First, digital by DAC7)1. . It is converted into video number 1, which is similar to the time, and sent to the monitor.

On the other hand, the digital RGB sent to the imprinter section 10
First, only the color signal being printed is selected by the signal selector 101, and only the necessary data for one line is written into the line memory 102.

One line of data held in the line memory 102 is the intermediate data of the next stage! It is converted into an achievement pulse suitable for the data by the A control means 03, transferred to the thermal head 104, and printed.

Now, color correction matrix 4 is used to print the image (
I am using ffi hue correction. this? This will be explained below. First of all, since the print is a subtractive color mixture, the three primary colors of the television signal, G and B (red, green) are suitable for printing.

cyan, magenta, yellow (cy,
Use MP, Y4) ink paper. At this time, it is ideal that the ink paper has a purity of 100%.

In other words, for example, M when only Cy is printed.

It is desired that the +Y6 component is 0. However, in reality, the MP/Y4 configuration is slightly included, and therefore the hue is slightly shifted from the hue of the input image. If this ink paper temporality is matrix 8, then if we reconsider Fig. 1 from the perspective of color characteristics, we can obtain the result as shown in Fig. 2. In other words, first, we can use the correction matrix for the input signals RQ, Go, and B11. , a correction called inverse IJ correction of the above A is applied.Then, ink paper adhesion A is applied in the line print section 10, and the print output is the same color component R0, Go as the input.
, Ho can be reproduced. On the other hand, on the monitor, the play-of-color correction matrix 8 applies the above-mentioned ink paper characteristics A to print and input signals and R, 0, Go, Bo, etc.
can be reproduced.

Next, an example of actual measurement of ink paper characteristics is shown below. Assuming that the input signals are Cyo, NLj'o, Y40, and the printed color is Cy and ML Y4, the following is obtained.

Next, one embodiment of the color correction matrix 4 will be explained with reference to FIG. In the figure, 11 to 13 are pants 7, and 14 is a sword calculator. Buffers 11-13 have a 1-channel configuration and include transistors 201-206. Resistance 204-206.
The Calorie device 14 is composed of a capacitor 207, and an amplifier 301. ~303. It is composed of reference resistors 304 to 306 and a reference power supply 307. Further, resistors 20 to 28 have a force ax and a low resistance for determining the sword ratio.

First input is 几. fg@ is inverted by the transistor 201 and outputted through the transistor 202 as the negative phase signal -R.
It becomes o. On the other hand, a positive phase output is generated via the transistor 203'7. Below G0. The same holds true for Bll.

Next, the operation will be explained. The mass output is determined by each resistance ratio. In other words, the resistance value of the resistor 304 is γ. , below as γRR, γGR, rBR as shown in FIG. 3), the output signal is expressed by the following equation.

Therefore, the resistance value may be set according to the above matrix A1. Hereinafter, for GB, all (all) may be set in the same manner. With this, the color correction matrix 4 can be realized.

Also, regarding the play-of-color correction matrix 8, the formula (
The resistance ratio may be determined according to [2].

Next, another embodiment of the present invention is shown in FIG. Components in the IC shown in FIG. 1 that have the same functions as those in FIG. 1 are designated by the same reference numerals. In Figure 4, 40 is a digital color correction device, and arithmetic circuits 401. It consists of a selector 402 and a data correction circuit 403.

Next, the operation will be explained. The input video signal is converted into three color primary signals R0, Go, and B in the same way as in FIG. Thereafter, the color digital signal read out from the image memory means 6 is converted into an analog signal by the DAC 7, and converted into an output video signal by the encoder 9. On the other hand, the three primary color digital signals RD and GD read out from the image memory means 6.

The data of the BD is corrected by the digital color correction device 4o, and then sent to the next line print section.

Here, in the digital color correction device 40 , data of one color to be printed is first selected by the selector 402 and sent to the data correction circuit 403 . - Calculate the correction amount of the selected color signal by the calculation circuit 4 (H), and calculate the correction amount of the color signal by the data correction circuit 40.
Send to 3. Here, in the arithmetic circuit 401, the above-mentioned formula +31.
(Performs a total of 41
are complementary colors and are represented by .

As a concrete calculation Perform the following treatment.

Here, one embodiment of the arithmetic circuit 401 is shown in FIG.

In the figure, 501 is an inverter group, 502 is a multiplier group, 503 is an adder, and 504 is a coefficient multiplier. The input GB signals are converted by the inverter group 501 as shown in the equation (bright), and become Cy·λiy−Y4, respectively.

According to the coefficients of the subsequent equation (3) or equation (9), each coefficient is output from the coefficient multiplier 504, and each term of equation (9) is output from the multiplier group 502. This coefficient also includes a sign. The output of each term is obtained 710 times by the next 7IO calculator 503, and each correction term of equation (9) is output.

In the above embodiment, the coefficient unit 504 and the increment unit group 502
We obtained 4 terms for each term in equation (9) using Ike's method.
y・N17. 'l' 1 (with 4 data as address input)
, OM method may also be used.

〔Effect of the invention〕

According to the invention, it is possible to correct the color purity of ink to reproduce colors faithful to the input signal, and at the same time match the hue of the monitor image.Q1 Printed images and monitor images that always have no hue shift It has the effect of obtaining

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a system diagram for explaining the operation of FIG. 1. FIG. 3 is a circuit diagram showing an example of an actual Δ Mado Vx circuit in FIG. 1, FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 1 is a circuit diagram showing an example of a circuit. 4...Color correction matrix. 6...ll! ili image memory means, 8... play-of-color correction matrix, 10... line print section, 40... digital color correction device. 7'-

Claims (1)

[Scope of Claims] 1. In a hard copy device for input video signals, an analog preprocessing section that processes three primary color signals from the input video signal, and an image memory means that stores the output processed signals;
It has printing means for hard copying the output of the memory means, and an analog post-processing section for restoring the output of the memory means to the original video signal, and correction for correcting the three primary color signals in the analog pre-processing section. 1. A color correction device for a video printer, characterized in that it has a matrix means and an inverse correction matrix means for inversely correcting the correction matrix in the analog post-processing section. 2. A color correction device for a video printer according to claim 1, wherein the correction matrix means is provided between the image memory means and the printing means.