JPH01190080A - Color image processing device - Google Patents

Abstract

PURPOSE:To output a natural picture when a monochromatic signal is outputted out of plural chrominance signals by providing a density detecting circuit to generate one picture signal out of plural color picture signals and a masking circuit to correct colors using the plural color picture signals for the title device and selecting output signals from both the circuits. CONSTITUTION:For the contents of the data of ROM40-42, masking table data for correcting the colors of the output of a printer are stored. Addresses A14 of ROM40-43 are used for a masking and the selecting of the table data of a block generated ROM and are made to select the table data by a signal 23 from a control circuit 21. Three signals C5, M6, and Y7 from a density converting circuit 4 are inputted to the address of a density detecting ROM50. A density detecting circuit 13 generates one density signal out of the three chrominance signals. A selector 64 selects any one out of signals from a processing circuit 61, a dither processing circuit 62, and a simple binarizing circuit 63 and outputs the selected signal to a printer part 20. Consequently, the natural picture can be outputted when the monochromatic signal is outputted out of the plural chrominance signals.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color image processing apparatus that processes color images by digital processing.

2. Description of the Related Art In recent years, devices that process color images, such as digital color copying machines, are required to have multiple functions.

In the monochrome copying mode of conventional digital color copying machines, a signal in which black components are extracted from multiple color image signals is processed and printed out (for example, in Japanese Patent Laid-Open No. 59-1
61979).

Problems to be Solved by the Invention Conventional digital color copying machines, etc. processed and printed out signals obtained by extracting the black component from multiple color image signals in monochrome copy mode, so it was difficult to copy color originals in monochrome mode. It was an unnatural image.

In view of the above problems, the present invention provides a color image processing device that outputs a natural image when outputting a monochromatic signal from a plurality of color signals in a color copying machine or the like.

! l! Means for Solving Problem a includes a density detection circuit that generates one image signal from a plurality of color image signals, and a masking circuit that performs color correction using the plurality of color image signals, and outputs the output signal from the density detection circuit. The method is characterized by comprising means for selecting an output signal from the circuit and an output signal from the masking circuit, and wherein the density detection circuit comprises a memory storing table data for converting a plurality of color image signals into one image signal. That is.

Effect of the Invention With the above-described configuration, the present invention can output a natural image when outputting a monochromatic signal from a plurality of color signals.

EXAMPLES A color image processing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the signal flow of a digital color copying machine using the color image processing apparatus of the present invention.

1 is red color data output from a part of the image scanner R12 is green color data G; 3 is blue color data B; 0 color signal data 1; 2. 3 are converted into densities by the density conversion circuit 4, and C5, M6 . Outputs Y7 signal.

The control circuit 21 switches various modes of the copying machine,
This is a circuit that performs settings. The m degree conversion circuit 4 is a control circuit 21
The density conversion mode is switched by the signal 22 from the . The masking circuit 8 receives the output signals 6 and 7 of the density conversion circuit 4.
．． 8, the masking circuit 8 performs masking to correct the turbidity of the ink in the printer section, and at the same time performs undercolor removal (UCR) and extraction of the black component.
"9° Cyan c'io, Magenta M'll, Yellow Y' 12 color signals are output. The masking circuit 8 switches the masking mode based on the signal 23 from the control circuit 21. The density detection circuit 13 outputs the signal 5. .6.7 is input, and one density signal D14 is generated from the three color signals.The selector 15 selects one of the signals 9°10.11, 12.14 and outputs the signal 16.Four colors When outputting to a printer in duplicate, selector 15 outputs signals 9.10,
Select 11° and 12 in sequence. When printing in a single color, the selection of 0 for selecting the signal 14 is determined by the signal 26 from the control circuit 21. The printer T correction circuit 17 is a circuit that corrects the output gradation characteristics of the printer section 20, and outputs a signal 18. The binarization circuit 19 is a circuit that performs pseudo-halftone processing on the signal 18, and outputs the binarized signal to the printer section 2.
Output to 0. The binarization circuit 19 selects the pseudo halftone processing mode by the signal 25 from the control circuit 21. The printer unit 20 is a printer that prints black, cyan, yellow, and magenta ink in a field-sequential manner.

The density conversion circuit 4 will be explained using FIG. 2. Second
The figure is a block diagram of the density conversion circuit.

1.2.3 are RGB color signal data input from the image sensor section, each having a data width of 8 bits.
Signals 2a, 22b, and 22c are from the control circuit 21 and have a data width of 7 bits.

30, 31. 32 is ROM (Read
0nly Memory). 1. 2.
3 and 22a, 22b, 22c are RO as shown in FIG.
It is input to addresses M30, 31, and 32. ROM3
0.31.32 outputs signals 5 and 6.7. 22a,
Signals 22b and 22c determine which conversion table data is selected from among the conversion table data in the ROM 30, 31, and 32.

Next, the data contents of the ROM shown in FIG. 2 will be explained using FIGS. 3 and 4. FIG. 3 is a diagram showing the funky run of each bit of the signals 22a, 22b, and 22c from the control circuit 21. The lower 3 bits adjust the density, the next 2 bits adjust the contrast, and the upper 2 bits set the level of background color removal.

FIG. 4 is a diagram showing the contents of table data of ROM 30.31.32. The horizontal axis is the ROM address AO-AT
It represents the data input to , and has the highest brightness at FFH.

The vertical axis represents the output data of the ROM address, and FFH is the highest density. As shown by the solid line in Figure 4+al, the ROM
The basic conversion function of 3O-32 is conversion to concentration. Fourth
As shown by the dotted line in Figure (a), seven types of table data are created by vertically moving the conversion table data in parallel. Seven types of density conversion table data are selected by setting the lower three bits in FIG. A linear curve is table data that simply inverts the input data without performing density conversion. 4) is a diagram showing table data having a background color removal function. As shown in FIGS. 4 to 4), the table data is such that the output becomes O for input data larger than a certain value. By forcibly setting the density of data to 0 when the density exceeds a certain value, the output can be set to 0 even if the background of the document read by the scanner is partially colored. Create 4!1 table data with different background removal levels and select using the top two bits shown in FIG. FIG. 4(c) is a diagram showing table data for adjusting the density contrast. As shown by the 0-dot line, the contrast characteristics are changed by changing the slope of the table data in the medium density region.

Four types of table data are selected using the two bits in FIG.

As described above, 128 types of table data can be selected: density adjustment 8 x background color removal level 4 x contrast adjustment 4. This selection can be set independently for each of the ROMs 30, 31 and 32, so even if the background color is colored rather than gray, the background color can be removed, and the contrast can be adjusted for each color.
By adjusting the density independently for RGB, 1111 colors can be adjusted.

Next, the masking circuit 8 will be explained using FIG. FIG. 5 is a block diagram of the masking circuit 8. 40
．． 41 and 42 are ROMs that store table data for masking, and 43 are ROMs that store table data for extracting black components. Density conversion circuit output 5, 6.7
is input to the address of ROM4O-43 as shown in FIG. The contents of the ROM data 40-42 store masking table data for correcting the color of the output of the printer. Address A14 of ROM4O-43
is used for masking and selection of table data of the acid generation ROM, and is selected by the signal 23 from the control circuit 21. For selection of masking table data, when changing the pseudo halftone processing method described later, masking table data and black generation table data suitable for the processing are selected. ROM40, 41, 42.43 each have signal 4
Outputs 7.48.49.9. Adders 44-46 subtract the output of the ROM 43 from the output from the ROMs 4O-42.

FIG. 6 is a block diagram of the concentration detection circuit 13.

Three signals C5, M6°Y7 from the density conversion circuit 4 are input to the address of the density detection ROM 50 as shown.

The table data of ROM50 is (MAX (C, M, Y
)+MIN(C,M,Y))×0.5. M
AX() is a maximum value selection function, and MIN() is a minimum value selection function. The density detection circuit 13 generates one density signal from three color signals.

The printer γ correction circuit and the binarization circuit will be explained using FIG. Figure 7 shows the printer γ correction circuit and 2
FIG. 2 is a block diagram of a value conversion circuit.

60 is R that stores table data for printer T correction.
It's OM. 16 is an output signal of the selector 15, 24 is a ROM table data selection signal from the control circuit 21, and the signal 15.24 is manually input to the address of the ROM 60 as shown. 61 is an error diffusion processing circuit, 62 is a dither processing circuit, and 63 is a simple binarization circuit. Selector 6
4 is 61, 62 by the signal 25 from the control circuit "21.
Select one of the signals from 63 and output it to the printer section 20. The signal 34 from the control circuit 21 is a 3-bit wide signal, and is determined by the signal selected by the selector 64 and the printing mode of the printer section. Signal 24 in Figure 8
This shows the selection of bits and printer gamma correction table data in the ROM 60.

When the selector 15 selects the signal 9-12 and when the selector 64 selects the output of the simple binarization circuit, the printer gamma correction table data selects linear. Linear is table data without γ correction. This is because the printer T correction has already been performed by the masking process.

As shown in FIG. 7, printer gamma correction table data to be selected is determined depending on which color is output by the printer in the monochrome copying mode and which output signal of the binarization processing circuit is output to the printer unit.

Effects of the Invention As described above, the present invention includes a density detection circuit that generates one image signal from a plurality of color image signals, and a masking circuit that performs color correction using a plurality of color image signals. and means for selecting an output signal from the density detection circuit and an output signal from the masking circuit, and the density detection circuit includes a memory for storing table data for converting a plurality of color image signals into one image signal. By doing so, it is possible to output a natural image when outputting a single color signal from a plurality of color signals.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the signal flow of a digital color copying machine using the color image processing device of the present invention, Fig. 2 is a block diagram of the density conversion circuit, and Fig. 3 is a block diagram showing the signal flow from the control +B circuit. An explanatory diagram showing the function of each bit, Fig. 4 is an explanatory diagram showing the contents of the ROM table data, Fig. 5 is a block diagram of the masking circuit, Fig. 6 is a block diagram of the density detection circuit, and Fig. 7 is an explanatory diagram showing the contents of the table data in the ROM. A block diagram of the γ correction circuit and the binarization circuit, FIG. 8 shows the signal bits and RO
FIG. 6 is an explanatory diagram of selection of M printer T correction table data. 4...1...Density conversion circuit, 8...Masking circuit, 13...Density detection circuit, 15...
...Selector, 17...Printer γ correction circuit,
21... Control circuit, 30.31, 32.40,
41,42,43゜50.60...ROM. Name of agent: Patent attorney Toshio Nakao
De''. Fig. 2 w, 3 Fig. Kang Tachibana lower party removed husband Contrast Doyo tone! 0
0----I don't want to remove the base material oo----ii
ooo 5 roasted. 110 Takai 111--+Nonia Fig. 5 Fig. 8 000-m-Linear 001-11 monochromatic force U-Mei f circle 1 010--Ikkusamura black dither processing Qll--Ikkuma color color basis Expanded Chori 100 --- Monochrome black error is Ft, R Kariri

Claims (2)

[Claims] (1) A density detection circuit that generates one image signal from a plurality of color image signals, and a masking circuit that performs color correction using the plurality of color image signals, and converts the output signal into the output signal of the density detection circuit. and means for selecting an output signal from the masking circuit. (2) The color image processing device according to claim 1, wherein the density detection circuit includes a memory that stores table data for converting a plurality of color image signals into one image signal. .