JPS61145990A - Chrominance signal conversion system - Google Patents

Abstract

PURPOSE:To obtain such a color image as desired color emphasizing a designated specific color, when a color to be corrected is designated on an image surface of a colors display image and its designated color is corrected to the utmost by converting a specific color's signal level and by making it applicable that the more the corrected color is receded from an initial color, the slower its signal level allows it to perform the correction. CONSTITUTION:Three colors signal image signals Bp, Gp and Rp which locate at the positions designated on the picture surface are inputted to a subtraction circuit 7 with a performance of inputting to a maximum saturation signal detecting circuit 4 together with the respective inputted image signals B, G and R and then each output is inputted to an absolute value circuit 8 to become signal ABS2 after being added by an adding circuit 9. And furthermore, the most saturated chrominance signals B0, G0 and R0 are calculated and outputted to input to a subtracting circuit 5. Each output obtained after being subtracted together with the image signals Bp, Gp and Rp is inputted to the absolute circuit to become signal ABS1 after being added by an adding circuit 10. Outputs ABS1 and ABS2 are inputted to a subtracting circuit 12 with a performance of outputting of beta setting apparatus 13 after being added by adding circuit 11. An output ABS3 obtained is inputted together with the correction signals alphay, alpham and alphac by a multiplier 15 and then multiplication outputs HHy, HHm and HHc are inputted to a multiplying circuit 16 together with the input image signal B, G and R.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a color signal conversion method for arbitrarily correcting the color of an arbitrarily designated location on a screen such as a color television.

(Technical background of the invention and its problems) Recently, there has been an increase in the tendency to make a hard copy of a scene on a color television or the like and preserve it for a long time to enjoy it.

In this case, the color TV's blue (B), green (G), red (R)
) A hard copy is made by developing yellow (Y), magenta (M), and cyan (C) dyes of a color photosensitive material based on the signal. Then, when looking at the finished hard copy, if you are dissatisfied with the color of this part, or if you want to change only this color, it is not possible to change only a specific color with conventional hard copy equipment. For example, if the amount of magenta pigment in blue is changed, the same amount of magenta pigment changes in all colors related to magenta, and color adjustment that satisfies the initial request cannot be obtained. Furthermore, it was not possible to change only a certain color by specifying an arbitrary point on the CR7 screen.

(Object of the invention) This invention was made under the above circumstances,
SUMMARY OF THE INVENTION An object of the present invention is to provide a color signal conversion method that changes only the desired color on the screen to obtain a color image of a desired color in which a specified specific color is emphasized.

(Summary of the Invention) The present invention provides the following features when performing color correction of a color display image:
By specifying the color you want to correct on the color display image screen and changing the signal level of the specific color, the specified color will be maximally corrected, and the further away you are from that color, the slower the correction will be. It is characterized by the fact that

(Embodiment of the Invention) FIG. 1 is a block diagram showing the principle of the invention, in which three color image values B, G, and R of a color television are input to a signal conversion circuit 1. As shown in FIG. Then, the specified position image signal 2 of the place specified by, for example, a light pen on the CR7 screen is used as BP, CP, RP, and the correction amount signal 3.
is α! , αOtori, and αC are each input to the signal conversion circuit 1 so as to specify the intensity of the color to be changed. As a result, only the specific colors of the BGR signal are converted into signals in the signal conversion circuit 1, resulting in the upper numbers B', G', and R' of one image.To explain the principle of signal conversion in the signal conversion circuit 1, first, When you specify the position of the part you want to change color on the CR7 screen using a light pen or the like, the three-color image signal Bp at that position is displayed.

Gp, Rp and the intensity α of the dye you want to change! , alpha intestine, alpha C
Correction amount signals 3 specifying the values are transmitted to the signal conversion circuits 1, respectively. Then, in order to change the amount of change depending on the degree of saturation of the color at the specified position, three-color images Bp, Op,
From Rp, the most colorful three-color signal Bo, Go
, find Ro. This is Bp.

From the magnitude relationship of each image signal Gp and Rp, for example, Bp
If Ha is the maximum value of the quantization level (LMAX
), and after determining this maximum value, determine the first minimum value. For example, if GP is the minimum, then Go
is the minimum value of the quantization level (LMIN).

Next, we will deal with the intermediate value between the maximum value and the minimum value, which inevitably has Rp of the other color as the intermediate value, and similarly calculates Re using the following equation.

(1) Here, LMAX and LNIN indicate the maximum and minimum values of the quantization level, respectively, and WAX, MID, and old N indicate the image signals Bp, Gp, and Gp at the specified positions, respectively. The current desired correction amount signals αy, α厘, αC and designated position image signals Hp, cp, Rp, which are obtained from the above as described above, indicate the maximum, intermediate, and minimum levels of Rp. The most colorful color signal No, Go,
Using Ro, and assuming that β is the value that defines the range of colors that can be corrected, the three-color image signals B and G on the CR7 screen are
, R, are converted and output image signals B', G
', R' are converted according to the following equation (2).

B'=H+α! ×(β-(In-Bpl+1G-Gpl
+1R-Rpl)-(IBp-Ha)+1Gp-Go
l+IRp-Rol)) In equation (2) above, if the value in curly brackets () is negative, it is set to 0, and these αy
, alpha layer.

The term related to αC is set to zero. Further, β can be arbitrarily set as a positive integer equal to or less than (quantization number of signal - 1). What the above formula (2) means is that the difference between the color of the specified point and the input color and the difference between the color of the specified point and the most colorful color are calculated, and the desired color is calculated. The purpose of this method is to obtain a converted output signal by changing the intensity of conversion depending on the amount of dye.

A block diagram of a specific example of the above signal conversion circuit l is shown in the second diagram.
The three color signal image signals Bp, cp, and Rp at the positions designated by the 0 screen shown in the figure are input to the maximum saturation signal detection circuit 4, and are inputted to each other, and their respective outputs are input to the absolute value circuit 8 ( 8B.

8G, 8R). These absolute value circuits 8B-8
Each absolute value is calculated in R, and the obtained absolute value outputs are added in an adder circuit 9, and the added value becomes an absolute value signal ABS2. On the other hand, the most colorful color signals Bo, Go, and Ro are calculated and outputted by the maximum saturation signal detection circuit 4 and are input to the subtraction circuit 5 for each of the three colors, and designated point image signals Bp, Gp,
Each output obtained by subtraction together with Rp is sent to the absolute value circuit 6.
(8B, 8G, 8R). The respective absolute value outputs obtained by calculating the absolute value in each of these absolute value circuits 6B to 6R are added in the adder circuit 10, and the added value becomes the absolute value signal ABSI. Then, after the absolute value outputs ABS1 and ABS2 obtained as described above are added in the adder circuit 11, they are input to the subtracter circuit 12 together with the output of the β setter 13 and subtracted, and the obtained absolute value calculation Output ABS3 is 3
Multiplication 1 for each color! 15 (15B, 15G, 15R) is the correction amount signal αy.

The multiplier outputs HHy, HHm, and HHc that are input together with αm and αC and multiplied together are inputted together with the input image signals β, G, and R to an adder circuit 18 for each three colors.
4, and when the absolute value calculation output ABS3 is negative, a negative signal JJ is output, and when the negative signal JJ is output, the relay 17 is excited and the relay contact 18 is By switching to the Jl side, the input image signals B, G, R, become the output image signals B',
They will be output as G' and R'. On the other hand, if the absolute value calculation output ^BS3 is positive, relay 1
7 is not excited, the relay contact 1st is on the J2 side, and each added value (B+HHy) of the adder circuit 16,
(G+HHm) and (R+HHc) are output image signals B
', G', R'.

By the way, the specific configuration of the maximum saturation signal detection circuit 4 is as follows.
As shown in the figure, the three-color image upper number Bp of the specified point
, Gp, Rp are 2 of subtractor 198.190°18R
and the difference signals SSt to SS3 between the two are inputted to each other.
Find the positive/negative judgment circuit 34 (348, 34G, 34R)
It is designed to be input. These positive/negative judgment circuits 34
B to 34R output a positive signal SS if the input signal 5Sl-SS3 is positive, and a negative signal FF if it is negative.
The signals are inputted to a plurality of AND circuits 20 so as to output an "L" signal when both S and FF are output, and an "O" signal when they are not output. Depending on which output condition among these AND circuits 20 is satisfied to output "1"',
The order of the magnitudes of the designated point image signals Bp, Gp, and Rp is determined. Each output of these AND circuits 20 is a multiplier circuit 22, a subtracter 21 (7) output (LMAX-LMIN)
The specified point image signals Bp, cp, and Rp are input together with the specified point image signals Bp, cp, and Rp, and after being multiplied, the specified point image signal Bp is sent to the division circuit 23.
, cp.

The input is divided along with Rp. After that, the absolute values are input to the absolute value circuit 24 and subjected to absolute value calculation, and each absolute value is input to the addition circuit 2B, where LMIN is added and the calculation output Bl, 82. Gl, G2. R1 and R2 are obtained. On the other hand, each output signal of the AND circuit 20 is sent to the multiplication circuit 23 by the set value LM from the LMAX setter 27.
It is input together with AX, and is further input to the multiplication circuit 30 together with the setting value LMIN from the LMIN setter 28, and is multiplied respectively to produce calculation outputs 83-BB, G3-GB, R1-G.
3 and R1 to R8 are input to selection circuits 31 to 33, and 8
One among 1 to B6, one among GINGB, R1-R
Only one of the six has a non-zero value, and all the others are zero, so the selection circuits 31 to 33 select the signals having these non-zero values, and the most colorful color signal They are output as Be, Go, and Ro.

As mentioned above, Fig. 3 shows the calculation of the above formula (1) using a concrete block diagram, and Fig. 2 shows the calculation of the above formula (2).
This is a concrete block diagram showing the calculation of the formula.

Thereafter, by coloring the YMC dyes based on the converted signal outputs B'', G', and R', a desired hard copy can be obtained.

Next, the above embodiment will be explained using specific numerical values. First, the input signals B, G, and R are 16 as shown in FIG.
Stage (4 bits) (maximum level “1 n, minimum level”
1G"). In this case, to obtain a hard copy, connect the densities of Y, N, and C to be converted with a straight line with the maximum being Dmax. Create a Y, H, and C density table for each signal level, and after signal conversion, color each Y, M, and C pigment based on this table to obtain a hard copy. , three signal levels B, G, R
If they are the same, an achromatic color is obtained, and the brightness of the achromatic color is equally divided by the brightness function.

Here, the quantized three color signals at the specified position are Bp-14, Gp-1, and Rp-14, which are a slightly dull green color.
, the maximum value is the same value for BP and RP, so the most colorful three color signals no and Go for this hue
, Ro is Bo=113. as mentioned above. Go-1,R
o-18 Therefore, if you set β to 15 and want to lower the cyan density of this color a little (α Peng-4/15), specify...
...(3) The result of equation (3) is obtained. Further, the result of equation (4) is obtained in which the converted three-color signals B2°sG2° and R2° of the most colorful green (B-18, G-1, R-18) are as follows. These results are summarized as shown in FIGS. 6 and 7.

Figure 6 shows how the signal is modified when the saturation of the input signal changes, when a slightly dull green color is specified and the cyan density is slightly lowered. It can be seen that the amount of correction is the largest at , and even for the same color, the more the color becomes less vivid, the smaller the amount of correction becomes. In addition, Figure 7 shows how the signal is modified when the hue of the input signal changes, when the most colorful color of green and a slightly dull color are specified, and the cyan density is slightly lowered. The case is illustrated, and it can be seen that the change in the specified color is the largest, and the change becomes slower as the hue changes. Furthermore, the lower the saturation of the specified color, the narrower the range of colors that can be modified. here,
If it is desired to change not only the density of cyan but also the density of yellow and magenta, various changes can be made by repeating the changes according to the configuration shown in FIG. 2.

Although one embodiment using equation (2) has been described here, this invention merely uses equation (2) to calculate 114th+L.
＋−p↓＋−1上hノ 1^i6 The cruel table] The judge is C
For example, if you don't like the color of a person's face on the R7 screen, you can specify the part you don't like and specify the intensity of that color without having to modify it using a hue board or the like. The object is to obtain a color image in which all parts of the same color as the specified part are modified in the same way, and the further away from the specified color the slower the modification. Therefore, regarding the means of implementation (2
) In addition to weapons, various methods can be used. For example, signal conversion can also be performed using the following equations (5) and (8).

・・・・・・・・・(5) (Here, the gradient of change can be set arbitrarily by the value of γ.) Below, the differences in correction using equations (2), (5), and (8) are explained. Explain briefly. Now, the change in the amount of correction in each of the above formulas is determined by the value in the curly brackets (),
When the amount of correction is maximized IC-Gp I+IR-RPl)
÷(IBp-Be l+ICP-Go l+IRp-R
If α is the proverb, then the relative correction amount RC+ in equation (2) is RCI-(β-α)/β ・・・・・・・・・(
2).

The relative correction amount RC2 in equation (5) is RCz-e-Q/″””(5)' The relative correction amount RCs in equation (8) is R(3-((β-α)lβ)1'γ...・・・・・・・・・
(8) It becomes ゛. In Figure 8, the quantization level is 18, and β
This is a graph showing the change in the relative correction amount of each equation with respect to α when is set to 15. In equation (2), correction is performed linearly with respect to α, whereas in equation (5).

It can be seen from equation (8) that the process is performed nonlinearly.

It also shows how the slope of correction changes depending on the value of γ.

Furthermore, although the above embodiment has described signal conversion when obtaining a hard copy from a color television signal, it is also possible to modify the colors on a CRT, and in this case, the amount of modification can be changed to B, G, As given by R, αB, α
G, αR), converted three color values B', G', R
'All you have to do is display the image on the color CRT using the signal.
In addition, although we have explained conversion on the CR7 screen of a color TV, there are many other uses for it, including display screens in industrial measurement displays, and color liquid crystal displays instead of CRTs, and these are not limited to color TVs or CR7 screens. All of these can also be applied when obtaining a hard copy from the screen.

(Effects of the Invention) As described above, according to the present invention, it is possible to change the color and amount of pigment at any location on the screen, and therefore it is possible to easily obtain a color image with desired coloring.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the invention in detail,
Figures 2 and 3 show its specific structure, two E-s FJ FRA F; A I÷1 + 9 Q
A diagram showing the relationship between +/bevel quantized signals, Figure 5 is a diagram showing the analytical density for converting the quantized signal to color density, and Figures 6 and 7 are the output signals for input signal levels after conversion. A graph showing an example of a change in level, and FIG. 8 is a graph showing a relationship between relative correction amounts of each correction formula. l...Signal conversion circuit, 2...Specified position image signal. 3... Specified dye amount signal, 4... Maximum re-signal detection circuit, s, 7. t2. is, 2t...subtraction circuit, 8,
8.24... Absolute value circuit, 11.10, 11.18,
213...Addition circuit, 13...β setter, 14.3
4... Positive/negative judgment circuit, 15, 22, 29.30...
・Multiplication circuit, 17... Relay, 20... AND circuit, 23... Division circuit, 27. LMAX setting device, 28-
LNIN setter, 31-33... selection circuit. Applicant's agent Yu Yasugata No. 6 Figure 7.

Claims (1)

[Claims] In a method of converting the color signal of a color display image, a color to be corrected is specified on the screen of the color display image, the specified color is corrected to the maximum by changing the signal level of the specific color, and the specified color is converted from that color. A color signal conversion method characterized in that the correction becomes slower as the distance increases.