JPS63212268A - Picture processing method for executing color erasing and color conversion - Google Patents

Abstract

PURPOSE:To prevent the large capacity of a memory and to prevent the complication of a circuit by constituting picture data of a color code indicating a color and density data indicating a density and converting the color code to a specific color to perform a color erasing and a color conversion. CONSTITUTION:The color code and the density data are stored for every picture element in respective memories 10-12, the color code is inputted to a white code generating circuit 31 and the density data is inputted to a binarization circuit 32, respectively. After the binarization, when the density data is not present, the color code inputted to the white code generating circuit 31 is converted to the white code to generate the white code and after the binarization, when the density data is present, the inputted color code is directly outputted. The color code outputted for every picture element from memories 35, 36 is converted according to an instruction code to execute the color erasing or the color conversion. Thereby, since the color code is mainly controlled, a complicate processing is not required, but the capacity of the memory may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing method that performs color erasure or color conversion by converting color codes when recording/storing image information.

[Background of the invention]

Conventionally, analog methods and digital methods have been known as methods for performing color erasure or color conversion in multicolor copying devices.

In the analog method, the light that exposed the original is separated into colors through a color filter, the light is directly exposed to the photoreceptor, and during development, the color is erased by combining multiple color toners using multiple developing devices for each color. , color conversion, etc.

For example, as shown in FIG. 11, visible light is blue B, green G,
When decomposed into red R, if the corresponding color is expressed using magenta, yellow, Y, and cyan C toners (their reflectance characteristics are shown in Figure 12), the following toner combination is used for development. ing.

8 color reproduction → M toner + C) Chi 0 color reproduction → Y toner + C) toner 8 color reproduction → Y toner + M) toner Therefore, for example, to erase (not develop) blue B color, use magenta M and cyan C toners. It is better not to develop the
Further, in the case of converting blue B color into red R color, development may be performed with Y toner and M toner when the blue B color is exposed.

Therefore, when analog processing is used, there is a problem in that the control becomes extremely complicated, mainly because the control is centered on the combination of developing devices corresponding to each color.

On the other hand, in the latter digital method, the light used to expose a color original is separated into complementary colors (for example, cyan and red) using a dichroic ink mirror, and images of each of the separated colors are created. As shown in Figure 13, CC
After reading with D1.2 and amplifying the read signal with amplifier 3.4, converting it into a digital signal with A/D converter 5.6, converting the red and cyan image data to the reference color (white).
to obtain the signals Vc (normalized cyan signal) and Vr (normalized red signal),
+Vr4 is stored in the luminance signal memo +78, 'Vc/
(Vc+Vr)J is set as the address data of the color difference signal memory 9 in which it is stored, the luminance signal data and the color difference signal data are outputted from each memory 8.9, and then the output data is set as the address of the black density memory 1O1 red density. The memory 11 and the cyan color density memory 12 are addressed, each output data is outputted via buffers 13 to 15, and the output image data of each color is used to expose the photoreceptor to laser light or the like, and take corresponding actions. I try to develop it with colored toner.

When erasing color, the color select circuit-16
A 2-bit color designation signal is sent to the buffers 13 to 15 to control on/off, and during color conversion, a specific color signal is developed with toner of the destination color. 17
is a clock circuit. -Also, when a color image is stored while being separated into colors, it is stored in independent memory planes (single-screen memory) 18 to 20, as shown in FIG. Which memory planes 18 to 20 are enabled and controlled by the color designation signal decoded by the decoder 21, and the clock from the clock circuit 17 is controlled by the counter 2.
The address is specified by the signal processed in step 2.

However, as long as such a method is adopted, the memory capacity increases with the number of colors, and even though memory is becoming larger and cheaper, the circuit becomes more complex, larger, and more expensive. This may lead to

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned complexity of the analog method and to prevent the increase in memory capacity in the digital method to perform achromatization and color conversion.

(Structure of the Invention) For this purpose, the present invention configures image data with a color code representing color and density data representing density, and converts the color code to a specific color to perform color erasure or color conversion. did.

〔Example〕

Embodiments of the present invention will be described below. In this embodiment, image data is captured from a color scanner or TV camera, and then the image data is color separated and a color code is generated for each pixel separately from density information. is generated, then stored, and then read out, after which achromatic seven-color conversion is performed.

(1) Regarding 0 color separation: Conventionally, as shown in FIGS. 13 and 14, black memory 10, red memory 11. The colors are separated by a cyan memory 12. For example, regarding the contents of the black memory 10, data is stored only in the T-shaped part (in this case, 4 bits/pixel) as shown in Table 1, and the other data is 'OJ'. . The same applies to the other red memory 11 and cyan memory 12.

In this embodiment, a color code (color designation information) for each color is attached to each pixel data along with density information. For example, when considering red and blue as chromatic colors, the color codes are: White = (1,1) =3 Black = (0,O) =0 Red = (1,0) =2 Blue = (0,l ) = 1, the density data r D J in Table 1 changes as follows: conventional value D → OD...black 2D...red ■D...blue It turns out. Also, for example, black memory l
Data is written in O in the T-shape in the form of 'OXJ (X=O to F indicates concentration data) as described above, but as shown in Figure 2 (al), data is written in a T-shape. ``301'' and the white color code corresponding value ``3'' will be appended to the location.The contents of red memory 12 are shown in Figure 2 (bl), and the contents of cyan memory 12 are shown in Figure 2 (C). The data will be as shown in .In this case, the memory is different for each color, but it is also possible to write in one memory.Then, the density data of each color obtained in the above manner is stored. Do the following:

(2) When storing as binary data: In this example,
If the image density data is binary-valued (with or without density) and there is density data after the binarization (other than white), the color of the image data is I tried to memorize the code.

FIG. 1 shows the entire block, and the same reference numerals are given to the same parts as those already explained. are stored for each pixel as shown in FIGS. 2(a) to (C), and addressed by the output data from memory 8.9, and the color code from each memory 10 to 13 is The white code generation circuit 3
1, the density data is input to the binarization circuit 32, respectively.

Note that the binarization circuit 32 performs binarization processing using the output from the threshold ROM 33 as a reference. 34 is an inverter.

Here, when there is no concentration data after binarization, that is, rO
j, an output of 'OJ is output from the binarization circuit 32, but at this time, this inverted signal 'IJ is output from the white code generation circuit 3.
1, and convert the color code input at this time to the "white" code '11J' 0 For example, if the binary output signal is P, and this Pl is 'IJ, a white code is generated. do.

In addition, when there is binary density data, the binarization circuit 32
'IJ is output from 'IJ', so the inverted '01 is input to the white code generating circuit 31, and in this case, the input color code is outputted from the white code generating circuit 31 as it is.

Table 2 below shows the input/output relationship of this white code generating circuit 31.

Table 2 This white code generation circuit 31 can be constructed using a logic circuit, ROM, etc.

The color code is stored in the memories 35 and 36 as described above.For example, of the 2 bits of the color code, one memory brain 35 is used for the upper bit, and similarly one memory is used for the lower bit. Use plane 36. Note that each of the memory planes 35 and 36 can store a desired image size as binary data.

At this time, if the color code is 3 bits, it is possible to store data in 8 colors (including white), and instead of the 7 memory brains required in the past, only 3 are needed, which increases the storage capacity. is less than half that amount.

(3) 0. When storing as ternary data: In this case, 1-bit information indicating the 3rd value data of the density of each color and 2-focus information using the color code are required. Normally, ternary data is used. 2-bit information is required to indicate this, but since this embodiment has a white code, if the color code is other than 0 and the ternary code is 'IJ, then the 3-bit level is used, and if it is 'OJ, the 3-bit level is used. It is possible to have a binary level. It is also possible to reduce the number of bits by the amount of white code. Furthermore, the number of memory planes is reduced by one compared to the usual size (of course, 2 bits may be allocated as ternary data and a total of 4 bits may be stored).

Therefore, in this case, it is possible to represent one pixel data (color + density) with a total of 3 bits, and while conventional methods could only store 3-color binary images, this example can store 3-color binary images. It becomes possible to store ternary images.

The third WA indicates a block in which this ternary data is stored. 37 is a ternarization circuit, 38 is a threshold value RO
M, 39 is Noah gate, 40 is AND gate, 41 is 2
It is a memory brain for value/ternary information.

In this FIG. 3, each signal pg l ps I p4
The logical value of +ps is determined as shown in Table 3 below.

Table 3 Therefore, if the ternary level is "white 1, r gray J%' black j, then at the r white J level, the P input to the white code generation circuit 31 is 'IJ.' As in the embodiment of FIG. 1, the white code fil.

occurs □. In this case, P is 'OJ.

Also, when r gray level, P is 'IJ, but p
Since s is 'OJ' and P4 is rOj, the input color code is stored as is.

Furthermore, when r black j level, P4 is 'IJ and P5 is'
Since it is OJ, the color code is stored as is, and since P2 is "1", it indicates a ternary level.

By creating stored information based on color codes using the method described above, it has become possible to significantly reduce storage capacity compared to the conventional method of storing color information as is.

In this embodiment, the colors are black, red, and blue, but the colors are not limited to these. Although color ghost correction is usually performed using a color pattern method after color separation, it is of course possible to store data using this method after performing color ghost processing. A block in this case is shown in FIG. 42 is a color ghost correction circuit.

Further, details of the color ghost correction circuit are shown in FIG.

This color ghost correction circuit 42 includes a shift register 4
201.4202, line counter 4203, decoder 4204, main scanning ghost removal ROM 4205, latch 4206, game) 4207a to 4207f,
4208a ~ 4208j' line memory 4209a ~
4209g, a data selector 4210, a ghost removal ROM 4211 for sub-scanning, and a tick 4212.

By the way, in order to process/record image data using the information stored in this way, it is not possible to use the output data from the memory as is.

This point will be explained below.

(a) Case in which multivalued data is stored: Suppose that data A, B, and C are obtained by simultaneously specifying the same address in each memory plane 35, 36, and 41 shown in FIG. In this case, A and B indicate color codes, but C is binary/
Indicates ternary information. Combinations for restoring the three colors and the three levels of "white J + ' gray J, r black J" using the data of A, B, and C are shown in Table 4 below.

Table 4 Therefore, it is necessary to sequentially create designation data for each color using the white code and each color code. Now, let us consider the case of performing achromatization and color conversion. Now, if we consider the combinations of achromatization and color conversion for red, blue, and black, we have 18 combinations as shown in Table 5 below.
A combination of streets is possible. The first bit (right) and second bit of the "r instruction code" are bits that indicate the code to be processed, the third bit is a bit that specifies two-color erasure in achromatic mode, and the fourth bit is a bit that specifies this in color conversion. When B/NO is rIJ, the bit indicates that the mode is to convert two colors into one other color.The fifth bit is a bit that selects achromatization and color conversion. When specifying achromatic. Although Table 5 does not describe the case where the image is inverted in black and white, the same thing is true in this case as well, as long as the color code after conversion is changed.

Table 5 From the above, it is sufficient to convert the color code output from the memory for each pixel according to Table 5 above.

As a circuit for realizing this, there is a circuit shown in FIG.

A processing circuit 43 performs color processing (achromatization and color conversion), and a circuit 44 outputs a signal of image data combined with density information to a recording section.

The delay circuit 45 is a circuit that delays the density information by the processing time of the processing circuit 43.

FIG. 7 is a circuit showing the contents of the color processing circuit 43 shown in FIG. FIG. 8 shows the contents of the achromatic circuit 431, which is composed of a two-color detection circuit 431L, a one-color detection circuit 4312, an OR gate 4313, and a color code conversion circuit 4314. The 72-color detection circuit 4311 is configured as shown in FIG. 9(a), and the 1-color detection circuit 4312 is configured as shown in FIG. First, the two-color detection circuit 4311 has latches 4311a to 4311c.
, -number output circuits 4311d, 4311e, color code cent output sections 4311f, 4311g, and an OR gate 4311h. Further, the one color detection circuit 4312 includes a latch 4312a.

- It is composed of a number output circuit 4312b and a color code cent output section 4312c. Figure 10 shows color conversion circuit 4
32 is a diagram illustrating details of FIG. This circuit also includes a two-color detection circuit 432L 4322, an OR gate 4323, a color code conversion circuit 4324, and a code set section 4325. The two-color detection circuit 4321 and the one-color detection circuit 4322 are constructed of circuits similar to the circuit shown in FIG.

In the above FIGS. 6 to 1O, the achromatic circuit 431
Alternatively, the color conversion circuit 432 determines that the value of the fifth bit ■ is "1".
As a result, the color erasing circuit 431 becomes "0", the color conversion circuit 432 is selected and becomes active, and the output color code of the unselected side becomes 'II'.
J (white).

Then, when the color conversion circuit 432 is selected and the value of the fourth bit ■ is 'IJ, the color conversion circuit 432 enters the mode of changing two colors into one other color, and the two-color detection shown in FIG. The circuit 4321 becomes active and the first and second bits ■
The two color conversion specified color codes according to ,■ are shown in Figure 9 (
Internal color code output section 4311f shown in a),
4311g, and when the input color code is detected by the match detection circuits 4311d and 4311e, 'IJ is output from there, and the color code to be converted is set to 4 in advance.
The color code conversion circuit 4324 shown in FIG. 10, which is set with bits, outputs the color code to which it is converted. In other cases, the input color code is output as is.

When the value of the fourth bit ■ is 'OJ, the mode is set to convert one color, and the one color detection circuit 4322 shown in Figure 1O becomes active, and one color is converted by the first and second bits ■ and ■. The code is set in the internal color code output section 4312c shown in Fig. 9, and when the input color code is detected by the match detection circuit 4312b, 'IJ outputs it from there, and the conversion destination set in advance is output. A color code is output from the color code conversion circuit 4324 shown in FIG. 1O. In other cases, the input color code is output as is.

Next, the achromatic circuit 431 is selected, and the third bit ■
When "11", the achromatic erasing circuit 431 enters the two-color erasing mode, the two-color detecting circuit 4311 shown in FIG. Set the color codes in order to the internal color code output sections 4311f and 4311g shown in FIG.
The color code to be input is the match detection circuit 4311d, 4
When detected by 311e, it outputs "1", and a white color code "11" is output from the color code conversion circuit 4314 shown in FIG. In other cases, the input color code is output as is. ' When the third bit ■ is "0", the mode is set to erase one color, the one color detection circuit 4312 in Fig. 8 becomes active, and the first and second bits ■ and ■ specify one color erasure. The color code is set in the internal color code output section 4312c shown in FIG. 9 (bl), and when the input color code is detected by the match detection circuit 4312b, 'IJ' is outputted from there, and the color shown in FIG. 8 is output. A white color code "111" is output from the code conversion circuit 4314. In other cases, the input color code is output as is.

In addition, in the above, the color code conversion circuit 4 of FIG.
314 or color code conversion circuit 4324 in FIG.
This can be performed using a lookup table using a ROM or the like, or a table set in advance using a RAM or the like. Moreover, gates can also be used.

〔Effect of the invention〕

From the above, according to the present invention, since the color code is mainly controlled, there is no need for complicated processing, unlike in the past.
Further, the memory capacity is small, and highly compressed data can be used as is for processing.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of color code storage in the image processing circuit according to the first embodiment of the present invention, and FIG. 2 ta) to IC) are explanatory diagrams showing the contents of black memory, red memory, and cyan memory for color separation. , FIG. 3 is a circuit diagram of color code storage of the second embodiment,
Figure 4 is a circuit diagram of the color code storage of the third embodiment, Figure 5 is a circuit diagram of the color ghost correction circuit, and Figure 6 is the entire processing circuit for achromatic 7-color conversion using color codes. 7 is a specific block diagram of the color processing circuit in FIG. 6, FIG. 8 is a specific block diagram of the achromatic circuit in FIG. 7, and FIG.
A concrete block diagram of the color detection circuit, (b) is a concrete block diagram of one color detection circuit, Fig. 10 is a concrete block diagram of the color conversion circuit in Fig. 7, and Fig. 11 is a BGR of light. FIG. 12 is a characteristic diagram of toner reflectance, FIG. 13 is a block diagram of conventional color separation processing, and FIG. 14 is a block diagram of conventional storage processing after color separation. Agent Patent Attorney Tsuneaki Nagao Figure 1 tn->F Binary/ternary information 4ryJ Color processing circuit Figure 8 Achromatic circuit 4312C1 Color detection circuit Figure 10 History L Color conversion circuit Figure 11 400500 (6 ) 7ω wavelength λka - Figure 12 Wavelength - Reflection characteristics of toner

Claims (4)

[Claims] (1) Image processing characterized in that image data is composed of a color code representing color and density data representing density, and the color code is converted to a specific color to perform achromatization or color conversion. Method. (2) The image processing method according to claim 1, wherein the color code includes a white color code. (3) The image processing method according to claim 1 or 2, wherein the achromatic mode is a mode for converting an input color code to a specific color code such as white. . (4) The image processing apparatus according to claim 1 or 2, wherein the color conversion mode is a mode for converting an input color code to a color code other than white.