JPS59163978A - Color picture processing device - Google Patents

Abstract

PURPOSE:To improve the picture quality and to change color tone or the like by applying electric processing to a color contrast signal and utilizing a color output means to attain color copying and display. CONSTITUTION:An original 1 is separated into three colors Y, M, C, they are converted into electric signals by CCD solid-state image pickup elements 4-1-4-3 and the signals are applied with a unique digital processing at a signal processing circuit 7 on the way. Further, the signals are converted into Y', M' and C' signals, ink nozzles of three Y, M, C colors are driven so as to obtain a color copy by subtractive color mixture again on paper on a paper drum 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a color image processing device, and more specifically to an iT color image processing device. The present invention relates to a color image processing device that electrically processes a gray signal and makes it possible to perform color copying and color display using color output means.

BACKGROUND OF THE INVENTION The copier is one of the earliest and most widely used devices in office automation (OA), which has become a hot topic. The majority of photocopiers currently on the market are for black and white, and color copiers are rarely seen except in cases of severe punishment.The reason for this may be the high cost of color copiers. Another problem is that the image quality is unstable.

For example, if we look at the image quality when a black and white copying machine makes a copy of a character fragment (1°Ill) and then uses that copy as a manuscript to make a copy of the copy (grandchild copy), the grandchild copy is made 4 to 5 times. Even after repeated copying, copy quality that can withstand practical use is maintained. On the other hand, if the same process is performed on a color text document using a color copying machine, the image quality deteriorates severely after two or three times, and moreover, color noise becomes noticeable. In other words, not only the shape of the characters written on the manuscript becomes distorted and the color density becomes lighter (or darker), but also colors that did not exist in the manuscript appear (
or disappear). The difference between the two is that black-and-white copiers are made to be suitable for copying documents where reproduction of halftones is not very important, whereas color copiers are made for copying photographs where reproduction of halftones is very important. This is because it is designed to be suitable for copying.

The reason why it is relatively good to make a copy of a character original using a black and white copying machine is that the gradation characteristics, that is, the gamma (gamma) characteristics of the black and white copying machine are muffled. FIG. 1 shows an example of the gamma characteristics of a black-and-white copying machine and a color copying machine. Figure 1 (A) shows the gamma characteristics for a one-way black copying machine, and Figure 1 (B) shows the γ characteristics for a color copying machine, where the horizontal axis is the original reflection density and the vertical axis is the copy after copying. It is a foul concentration. With a black-and-white copying machine, if the original density is intermediate, the copy will be
'i What I is likely to be unified into either concentration or low concentration
I can see what's on the other side. The ability to change the gamma characteristics of a color copying machine to make the characteristic slope as similar to that of a black and white copying machine is the RF function.

However, in that case, as the complex original color of 1 tB becomes available as a grandchild copy, it gradually converges to one of six colors in total, including the three primary colors and their mixed colors. In other words, subtle colors are not preserved, no matter how intense their density level.

Further, as a similar conventional technique, there is a pseudo-color method in which a specific color is associated with each gradation of the density level of a black and white original document and outputted. Due to the correspondence between gradation and color,
The two methods are commonly known as the Rainhaw conversion method, and the warm-to-cool color conversion method, which is often used for computerized tomography (CT) images in the medical field. However, in this case, the input image is monochrome-1, and the output colors are truncated in appropriate correspondence to the gradations, so colors that do not actually exist are output. These conventional similar techniques do not have any conventional example in which the input image is in color.

Purpose The present invention has been made in order to improve the drawbacks of the prior art as described below.It not only significantly improves the image quality of color copies and color displays, but also allows the color tone of copies and displays to be changed arbitrarily. The purpose of the present invention is to realize a color image processing device with high functionality.

EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a color copying machine according to an embodiment of the present invention. In the figure, manuscript IJ-.

The color gradation image passes through the lens 2 and reaches the three-color color separation gicchroic mirror 3, where it is divided into yellow (Y), yellow (Y),
The light is separated into three color spectra of magenta (M) and cyan (C), and images are formed on CCD solid-state image sensors 4-1, 2, and 3. Further, the optical spectrum of Y, M', and C is converted into three electric signals, and the video amplifier 5-1
．． After being amplified to a predetermined level by 2.3, the A/D converter 6-1.2.3 converts the digital values Y, M
, C, respectively. A signal processing circuit 7 converts the signals Y, M, and C into signals Y', M', and C', respectively.

This will be explained in more detail with reference to FIG. to-
1, 2, and 3 are D/A converters; 8-1, 2, and 3 are inkjet printer heads using Y, M, and C inks, respectively; and 9 is a paper drum.

Yellow (Y), cyan (C), and magenta (M) are blue (
B), B (G), has a complementary color relationship with red (R), Y,
Full color printing is possible by changing the 41 color ratio of any of M, C or R, G, B (RGB
is suitable for additive color mixing, and YMC is suitable for subtractive color mixing). In the embodiment described above, the inkjet printer head is of a type that can record intermediate tones by converting the strength of the input voltage into the relationship between the size of ink droplets. It is also possible to use a tod-to-turn method that expresses intermediate tones using a specific pattern.

In other words, the operating principle of the color copying machine of this embodiment is to color-separate the original l into Y, M, and C, convert this into an electrical signal by the most image element 4-1.2.3 of the CCD solid state 1, and After performing unique digital processing in the signal processing circuit 7 of
, C's ink twist! ', 17° movement paper drum 9-
It is intended to obtain a color copy using the i-formation method 17 self-color again using the paper No. 1-.

FIG. 3 is a more detailed block diagram of the signal processing circuit 7 shown in FIG. 2. The three-color human-powered image values Y, M, and C are each input values! - line 71-1.2.3. 72-1 to 72-7 are digital color band pass filters that separate the input color signal into seven colors.

Of course, the colors of the tumors are limited to seven colors, but any color may be used.

Here, the seven colors are θ (OR), red (R), and green (G).
, blue (B), pink (PK), purple (PL), and fungi (Y).Black is considered a special color and can be processed using a similar processing circuit. Also, white is expressed by the white background of the original by not printing it. 73 is a maximum value detection circuit which selects and outputs the maximum value among the seven color band pass filter outputs. Therefore, the maximum value M is output to the signal line 77, and the color code P corresponding to the maximum value is output to the signal line 79. A comparator 74 determines the magnitude of the maximum value M and a predetermined slice level value S. When M>s, the Q signal of the output line 78 is set to high level (H), and when not, it is set to low level (L).
). 75 is a color generator, and its output line 7
6-1.2.3 Generate Y', M' and C' color signals.

! When the e'r line 78 is L, it indicates that the color is not specified and white is generated. Also, the side where the signal line 78 is H is A;
Various color signals are generated according to the color code signal P sent from line 79. Table-1 shows the color code P.
Color information for 'i Y', M'.

The relationship between C' is shown.

Table-1 In the same table, ylm and C are 7 colors plus white.

Yellow output Y' to form black, macenter output M
', and a coefficient that determines the ratio of the cyan output C'.

In the example, the maximum output value is 63, and in this case Y', M
', C' output values are listed in the table. Also y=m=c
Since the absolute sensitivity of the inkjet is adjusted so that when = 1', the result is black, by taking the relative outputs of y, m, and C as shown in Table 1, the output values Y', M', C' is determined and used to generate various colors. For example, when printing orange, Y' becomes 19, M' becomes 12, and C' becomes O. Accordingly, the Infusiera printer head 8-1.2.3 shown in FIG. The cyan ink is 19, 12, and 12, respectively, on the paper.
O'1lil1 and II; are combined to form an orange color on the paper surface.

It is also easy to output by changing the color J.

For example, in Table 1, when the blue color code o6 is obtained, the correlated red color signal 31.31.
0, and when the red color code 01 is obtained, the correlated blue color signal 0.31.31 may be output. By doing this, you can obtain an output with a tone of red and blue swapped.

In FIG. 3, a specific example of the constituent elements is shown as a comparator 74 (-) made by Texas Instruments Inc.
2 TL ICS″N7485, maximum value detection circuit 7
3 can also be configured by combining a plurality of similar ICs. Color generator 75 is bipolar memory MB manufactured by Fujitsu.
It can be easily configured using three 7051s. In the memory, the values Y', M', which are obtained by multiplying the coefficients D "l', m, C shown in Table 1 by the maximum output value 63, rounded to the decimal point, are stored.
A color generator can be constructed by writing C' and converting it into a color code P. The digital color pantohas filters 72-1 to 72-7 will be described in detail below with reference to FIG. 284.

FIG. 41 is a block diagram of an embodiment of a digital color band pass filter according to the present invention. Although only the digital color bandpass filter 72-3 in FIG. 3 is shown in the figure, the other filters have the same circuit configuration as in FIG. 4. This circuit performs the following calculations between the input signals Y, M, and C and the output value ηG. That is -1! IQ formula where Y sl, M s and Cs are yellow, masenk and cyan marks! <(The signal value is obtained by multiplying the values y, m, and c shown in Table 1 for each color by the output of color copying/iB maximum value 63.For example, if the left side CF of equation (1) for green is Replace with G, yellow (, Y)
and cyan (C) are both 0.5 and magenta (M) is 0, so Ys, Ms, and Cs are 31 and 0, respectively.

It will be 31. Equation (1) represents input color signals Y and M.

This is to find the correlation between C and the standard color signals Ys, Ms, and Cs, and when the correlation is maximum (that is, when it is determined that they are the same color), CF = 1, and as the correlation decreases, CF = O. Asymptotically.

In FIG. 4, 101, 104, 105, 106.
113, 114 and 115 are multipliers, 102.103,
116, 117, 118 and 121 are reciprocals, 107,
108. and 109 is a reducer, 119 and 120 are adders, 110. ill and 1.12 are absolute value calculators. The part surrounded by the broken line 122 in the figure is a normalization circuit. Y
, M, C and Ys, Ms, Cs, the amplitudes of the inputs Y, M, C are normalized here. Here, processing is performed to make the amplitude of Y equal to Ys. In other words, Y
S (7) Fi number 1 / Y s is determined by the reciprocal unit 102 and multiplied by the input Y by the multiplier 101 to obtain Y /
Y s. The reciprocal Y s /Y of this value is obtained by a reciprocal unit 103 and multiplied by the original input Y in a multiplier 104 to obtain Y d T4. Therefore, the normalized output YN is made equal to Ys. At this time, Y s /Y is a normalization coefficient, and by multiplying input M and input C by this in multipliers 105 and 106, respectively, normalized outputs M, J, and C- are obtained, respectively. The result of the operation "-" is YN,
The relative ratio between MN and CN is the original input Y
, M, and C are the same, but the vibration 1 is normalized to the magnitude when Y is set as Ys. Next, the subtractor 107,
108 and 109, the standard color signals Ys and M
s, Cs are subtracted, and further absolute value circuits 110, 111
, 112 to obtain the absolute value output. For yellow, it is 1Ys7Y by multiplier 113 and reciprocal 116.
Obtain s l / Y s. Similarly, 114°117 and! 115 and 118 execute division for magenta and cyan. The result obtained above is sent to the adder 119
, 120, the sum is obtained. The addition of +1 to the denominator on the right side of equation (1) is executed by setting the carry power to H in the adder 120. Finally, the reciprocal is taken by the reciprocal unit 121 and the calculation of equation (1) is executed.

To show a specific example of the components in FIG. 4, the multiplier is a US TRW
8x8 bit parallel multiplier MPYO08HJ5C5 manufactured by
Alternatively, a bipolar PROMMB714LH manufactured by Fujitsu may be used as a multiplier. Input color signals Y, M,
If it is C or 6 Bits, apply input Y to the address inputs AO to A of MB7141H, and input Y to the remaining address inputs A.
Apply 1/Ys to 6~All and output data 0□
From ~0 et al., it is possible to directly read out the 4ji of Y/Ys that has been stored in advance. The advantage of using FROM as a multiplier is that while it is also advantageous in terms of cost, 1117, which requires rounding of the initial multiplication result, is a pre-rounded Ml. The point is that the rounding operation can be executed without using a FROM.If you further increase the precision of using FROM, you can perform the functions of the reciprocal operator 102, 103 and the multiplier 101 with one FROM. In other words, if the human variables Y and Ys are used as address inputs, the final value Y s / Y of all the subsequent 9 results can be stored in FROM in advance.Similarly, the subtracter 107 and the absolute value circuit i
The arithmetic circuit consisting of to, the lock reducer 113, and the reciprocal unit 116 can be realized with one FROM (MB7141H). In this case, the address inputs are YH and Ys, and the data output is the result of the IY-Ys l/Ys arithmetic unit.

Generally, all logic circuits in which the bit configuration of the input signal or the number of trace lines of the FROM is less than 7 traces, and the pit or 4 elements of the output signal are less than or equal to the number of data lines of the FROM can be replaced with FROM. However, it is not used in ordinary logic circuits because of the generation of glitch noise due to temporal irregularities in FROM outputs and cost issues. Adders 119 and 120 can be constructed using 5N74L3283 manufactured by Texas Instruments. Further, the final stage reciprocal calculator 121 is constructed using Fujitsu's MB7123H. That is, the case of ζJO on the right side of equation (1) is associated with the memory address O, and the maximum value 63 of the embodiment is written as the result of the reciprocal operation. Thereafter, the data value increases by 1 each time the address increases by 1.
All you have to do is write down the details that will decrease gradually. In this way, it is possible to easily avoid the incomputability of division operations where the denominator is O. When the absolute (11'i circuit 110 is configured alone, it can be configured using MB71.23H. In that case, for example, Bit 6 is used as the sign p[.). By the way, as mentioned above, YN eventually becomes Ys. Since they are equal, the multiplier 104 can be omitted.

From the above explanation, the circuit of FIG. 4 of the embodiment is a FROM
7 adders Can be configured with a total of 4 λ4-11 ICs. Therefore, a color bandpass filter for seven colors can be easily realized at a practical cost.

) The configuration of the embodiment of the present invention shown in Figures 53 and 4 is as follows:
It attempts to faithfully execute @ calculation according to formula (1), but as mentioned above, even if the circuit is miniaturized by using <FROM'' by hand, it is not possible to realize color detection that exceeds seven colors. This results in an increase in the size of the circuit. Therefore, if the output Q is to be binarized by the comparator 74 in Fig. fpj 3 someday, if the calculations in the middle are reduced to about 4 bits, the circuit configurations shown in Figs. All circuits except density level 75 are integrated into one FRO
It is also possible to represent the M element. FRO in that case
The data written to M will be extremely complex, but
It can be easily programmed using a personal computer in a language similar to RAS I C. To outline the method, first, the execution program of formula (1) is assembled as a subroutine, and a subroutine for detecting the maximum value, a subroutine for determining the size based on the slice level S, and a reference table shown in Table 1 are also created. Furthermore, create a main program that calculates outputs P and Q from inputs Y, M, and C, secure a RAM area to hold the calculation results, and input Y, M, and C here.
It is good to output the result of 31 calculations and use it.

Further, in the above-mentioned embodiment, the color was determined using the formula (1), but it is also possible to use another similar formula that uses the 1'' target for color determination. Further, in the embodiment shown in FIG. 3, the case where color determination is performed for each pixel is shown. It is obvious that color discrimination may be performed by averaging several pixels.

Furthermore, in the embodiment described above, a case was described in which the maximum value detection circuit 73 was used. As is clear from Table 1, if we look at the correlation of the coefficients y, m, and c for determining the proportions of color signal inputs Y, M, and C among the seven colors, we can see that there are considerable differences. Therefore, a plurality of color bandpass filters 72-
If you connect a simple comparator circuit immediately after 1 to 72-7 and create a structure that allows you to set the slice level appropriately, you can get 2 or more.
It can be said that the fff possibility that the outputs of ; are generated simultaneously is small. Therefore, it is also possible to realize a color image processing apparatus with a simplified configuration in which the maximum value detection circuit 73 is omitted and the color density level 75 is accessed by decoding the outputs of a plurality of comparators.

Here, to summarize the operation of the color copying machine of the above embodiment according to the present invention, in FIG. In this process, each color is decomposed into three digital color shades of Y, M, and υ/C. If the colors of the originals are the same, the ratio of the sizes of Y, M, and C is constant even if the densities are different. Therefore, the signal processing circuit 7 (1) determines which color combination the input Y, M, and C signals represent; (2) compares the color density of the determined color with a predetermined slice level S; 3) If it is higher than the slice level S, it is assumed that a significant color signal has been received, and a color signal of a correlated color is generated, and if not, a color signal of, for example, white is generated.

Therefore, to make it easier to understand, the highest value of the color density level of a certain color is expressed as 100%, and the lowest value of 714 is expressed as 0%.
By setting the slice level S in (2) above at 50%, even if the original has a light density with a color-1a level of about 60%, it is possible to obtain a copy with high clarity by converting it back to 100% density. 7! I can do it. Conversely, even if there are stains on the document with a color density of 30%, they are converted into white signal numbers. In other words, in the embodiment, the l/n is not copied and printed. Therefore, it is possible to obtain a clear and easy-to-read color copy even from a color original that has a slightly overlapping number of colors.

Furthermore, even if the original document is written in a mixture of characters such as red, blue, green, and purple, it is possible to obtain a grandchild copy without degrading the quality of the characters. Of course, if the present invention is configured to have multiple colors, even subtle colors can be preserved through (1) adult color processing and threshold discrimination, so full-color image originals can be copied without degrading the image quality.

In addition, as a special application of the present invention, editing functions for the colors of the gods can be easily executed, such as converting only characters written in red to a white background and erasing them, or converting blue to yellow.

As described in ``Effects'' (2), according to the present invention, even if an original is repeatedly copied, color clarity is not lost, color noise is prevented from being mixed in, and color copies with extremely good image quality can be obtained. I can do it. Furthermore, according to the present invention, it is also possible to easily copy or display original documents with different color tones. Therefore, it is possible to easily realize a color image processing device that also has an advanced color theory collection function.

[Brief explanation of the drawing]

Figure 1 (A) shows the original reflection density vs. copy reflection density characteristic of a black-and-white copying machine; Figure 1 (B) shows the original reflection density vs. copy reflection density characteristic of a conventional color copying machine; and Figure 2 shows the characteristics of the present invention. FIG. 3 is a more detailed block diagram of the signal processing circuit of FIG. 2, and FIG. 4 is a more detailed block diagram of the color bandpass filter of FIG. 3. Here, 1... Original, 2... Lens, 3... Guicroic mirror, 4-1, 4-2, 4-3, .
・・CCD solid-state image sensor, 5-1.5-2.5-3・・
・Video amplifier, 6-1.6-2.6-3...A/D
Controller/Heater, 7...Signal processing circuit, 8-1.8-2
．． 8-3... Inkjet printer head, 9...
・Paper drum, 1o-1, xo-2, 1o-3...D
/A converter.

Claims (1)

[Scope of Claims] (1) A plurality of color/human band pass filter means for selectively passing specific color information consisting of a first color signal; a color information extracting means for extracting a specific value of the color information output from the color information extracting means; a determining means for determining whether the value of the specific color information output from the color information extracting means exceeds a predetermined threshold; A color image processing apparatus comprising: a color signal generating means for generating a second color signal correlated to the specific color information according to the output of the means. (2) The color signal generating means is characterized in that it generates a second color signal correlated to the specific color information when the output of the discriminating means is true, and does not generate the second color signal when the output is false. The color image processing device 6 (3) converts the first color signal into Y, M, C
Then, the color filter means that selectively passes the color information of the claw foot based on the standard color signals Ys, Ms, and Cs outputs the color information value CF of the calculation result of the linear equation. A color image processing device according to claim 1, characterized in that: (4) The color information extracting means extracts the maximum value of passed color information among the outputs of the plurality of color band pass filter means. Color image processing device (5) A number of color bandpass filters for selectively passing a specific color [old report] consisting of the first color signal, and a passing color filter of the output of the color bandpass filter means. a plurality of determination means for determining whether the value of exceeds a predetermined threshold;
A color image processing device '6゜ characterized by comprising a color signal generating means for generating a second color signal correlated to the passing color information according to the output of the discriminating means.