JPH04335772A - Color picture processor - Google Patents

Abstract

PURPOSE:To form a marker in one color as a clear graph independent of a way of drawing by outputting a color code as a code identifying 7 pure colors and converting a signal into a single color signal depending on the color code in the color conversion of the marker. CONSTITUTION:A color code generating section 21 fetches a 6-bit RGB standard density data from a standard density conversion section 3 and outputs a color code of 3-bit RGBYMCK (7 colors). A 1st color reproduction processing section 22 implements color conversion by a ROM storing a color conversion table. A 2nd color reproduction processing section 23 fetches an RGB data and outputs one color among 7 primary colors and uses the conversion table in this case. Selectors 24,25 select the processing sections 22,23 by a CPU 6, a marker color conversion section 26 detects a color of the marker to convert a black character in the marker into one pure color. When the selectors 24,25 select the processing section 22, the usual color reproduction processing is implemented and when the selectors 24,25 select the processing section 23, a color close to the color of the marker is selected and the marker is outputted by a prescribed density.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention provides a color reproduction processing unit that converts an original image signal expressed in RGB into a recording color signal expressed in YMC, and a color reproduction processing unit that converts a document image signal expressed in RGB into a recording color signal expressed in YMC, and a color reproduction processing unit that converts a marker area portion into a specific color signal corresponding to the marker color. The present invention relates to a color image processing device including a marker color conversion unit that converts into colors.

0002

[Prior Art] Conventionally, color images such as character drawings and photographic images are optically read by dividing them into the three primary colors of light, RGB (red, green, blue). There is a color image processing apparatus that converts the image into a recording color and records the image on recording paper using an output device such as an electrophotographic color copying apparatus based on the converted color.

FIG. 6 is a system diagram showing one example. The image information (optical image) of the original is color-separated into RGB by a dichroic mirror (not shown), and the obtained R component original image is converted into an electrical image signal by the CCD1R.
The component original image is converted into an electrical image signal by the CCD 1G, and the B component image signal is converted into an electrical image signal by the CCD 1B. Then, the RGB image signals obtained here are converted into, for example, 8-bit (256 gradation) digital signals in the next stage A/D converters 2R, 2G, and 2B. During this A/D conversion process, shading correction is also performed simultaneously based on the image data of the reference white plate.

Reference numeral 3 denotes a standard density conversion unit that converts the 8-bit RGB digital image signals output from the A/D converters 2R, 2G, and 2B into 6-bit standard density data, and the RGB data obtained here. The standard density signal is input to the color code generation section 4. Then, the color code generating section 4 generates a 2-bit color code. This color code is a code indicating whether the pixel is white/black/chromatic (e.g., white: 00, black: 01, chromatic: 10
).

Reference numeral 5 denotes a variable density conversion unit that converts the density information of the 8-bit RGB color components output from the A/D converters 2R, 2G, and 2B. Become. This ROM5R
, 5G, and 5B are selected based on data from the CPU 6. The CPU 6 receives operation signals from the color balance key 7, density key 8, mode key 9, etc. provided on the operation panel, and outputs data corresponding to the input signals. The color balance key 7 is a key for adjusting the distribution ratio of RGB, the density key 8 is a key for adjusting the density of RGB individually, and the mode key 9 is a key for outputting density correction data corresponding to photo mode and text mode. It is. Image quality adjustments are also made here.

10 is a color reproduction processing section, which is a 6-bit R
A process is performed to convert an image signal expressed by GB density information into a recording density signal expressed by 8-bit YMCK. For example, a ROM storing a conversion table is used for this conversion process.

Reference numeral 11 denotes a marker color conversion unit that detects an area marked with a marker of a specific color (marker area) on the document and converts an image existing within the area into the color of the marker. Note that the marker color converter 11 outputs a color density signal corresponding to the color to be currently recorded (MYCK colors are individually and sequentially selected (scanned) and recorded).

Reference numeral 12 denotes an image processing unit that performs various image processing such as filter processing, scaling processing, and shading processing on the recording density signal;
3 is a PWM multi-value conversion unit that performs PWM (pulse width modulation) to convert 6-bit density data into multi-value data, and 14 is a color image formed by sequentially overlapping toner images of each color of YMCK on a photoreceptor drum. An example of this is a laser printer unit.

[0009]

By the way, the marker color conversion section 11 described above is a processing section that converts the portion of the black text on the document surrounded by the marker to the same color as the marker. FIG. 7 is a diagram showing the state of this marker color conversion. In this conversion process, the document 15 is read, for example, with the X direction as the main scanning direction and the Y direction as the sub-scanning direction, and the color of the marker MC and the area 16 surrounded by the marker MC are detected.
The black characters 17 within the area 16 are converted to the color of the marker MC and recorded. For example, if the color of the marker MC is magenta, the characters surrounded by it are recorded on the recording paper 18 in magenta (see the right side of FIG. 7). Note that the color of the marker MC itself is removed.

However, in determining the marker color, the color data of the marker MC obtained by sampling is valid when the color code at that time is a chromatic color code; There is a considerable difference in shading depending on the direction of the document, and if the marker MC portion overlaps not the white portion of the document but another color, it will be detected as a color different from the color of the marker.

[0011]Therefore, there is a problem in that the color recorded after marker color conversion is greatly affected by how the marker is drawn and becomes unstable.

[0012] Therefore, it is possible to use a color code, but as described above, this color code only identifies whether the pixel is white, black, or a chromatic color, and cannot be used as is.

[0013] An object of the present invention is to provide a color image processing device that can solve the above-mentioned problems by using a color code that can identify a large number of pure colors.

[0014]

[Means for Solving the Problems] The present invention includes a color reproduction processing unit that converts an original image signal expressed in RGB into a recording color signal expressed in YMC, and a marker area corresponding to the marker color. A color image processing device comprising a marker color conversion unit that converts to a specific color, the color code that creates a color code indicating the color of each pixel as at least one of six colors of YMCRGB from the original image signal. It is equipped with a code generation section.

In the present invention, it is preferable that the marker color conversion section converts the marker area into one color determined only by the color code.

It is also preferable that the color reproduction processing section converts the recording color signal of the pixel into a signal of one color determined only by the color code.

[0017]

[Examples] Examples of the present invention will be described below. FIG. 1 is a block diagram of the main part A of one embodiment. This main part A is a part that can be replaced with part B surrounded by a broken line in FIG. In FIG. 1, in this embodiment, the color code generation section 21 takes in 6-bit RGB standard density data from the standard density conversion section 3, and 3-bit RGBYMCK (
Outputs the color code of 7 primary colors). 22 is a first color reproduction processing section equivalent to the color reproduction processing section 10 described in FIG. 6; 23;
imports RGB data and generates a density signal of one of the seven primary colors (Y, M, C, K, R=Y+M, G=Y+C,
B=M+C) is a second color reproduction processing section that outputs RO
A conversion table using M is used. 24 and 25 are selectors for selecting the first color reproduction processing section 22 and the second color reproduction processing section 23, and switching is performed by the CPU 6. Reference numeral 26 denotes a marker color converter, which detects the marker color and converts the black characters in the marker area into one pure color (specific density) determined by the above-mentioned color code.

The marker color conversion unit 26 is configured as shown in FIG. Reference numeral 261 denotes an area detection unit for detecting the marker MC and extracting the area surrounded by the marker MC to generate a marker area signal Q (signal indicating the area surrounded by the outer contour part of the marker MC). The area extraction unit 261 performs the following operations. As shown in Figure 3,
The marker signal obtained when scanning (main scanning) the scanning line s on the document 15 on which the marker MC is drawn is shown in FIG.
Ss, and the area signal obtained in the immediately preceding scanning line s-1 is Qs-1. Here, the AND signal (Qs-1) x (MSs) of both is taken, and the edge detection pulse Rs from its rising edge to its falling edge is
Create. Then, a logical sum signal Qs of the marker signal MSs and the edge detection pulse Rs is created. This signal Qs
becomes the marker area signal Q of the scanning line s. Similarly, if the marker signal obtained on the scanning line t is MSt and the area signal obtained on the immediately preceding scanning line t-1 is Qt-1, here too, the AND signal of both (Qt-1
)×(MSt) and create an edge detection pulse Rt from its rising edge to its falling edge. Then, a logical sum signal Qt of the marker signal MSt and the edge detection pulse Rt is created. This signal Qt becomes the marker area signal Q of the scanning line t. As described above, the area Q of the marker MC is detected in each scanning line.

Reference numeral 262 in FIG. 2 is a marker color sampling section, which takes in the color code of a pixel within four pixels from the edge of the marker, generates a sampling signal H, and sends it to the marker color density determination section 263. . The marker color density determining section 263 takes in the monitoring signal E from the marker sampling monitoring section 264 and finally determines the marker color density. That is, when the color code at the time of sampling is other than K (black), the marker sampling monitoring unit 264 outputs the monitoring signal E that makes the color code indicated by the sampling signal H valid, and only in this case, the marker color density is determined. The unit 263 outputs a standard color density signal for that color code.

Reference numeral 265 is a marker removal unit for removing the marker MC so that it will not be recorded.
), the input black K data is passed through as is, and when YMC recording is being performed (when the scan code is Y
, M, or C), only the black data in the marker area is passed through using the marker area signal Q and the color code.

Reference numeral 266 denotes a black color conversion unit, which is configured to perform multiplication only within the marker area and pass black data as is in other areas. That is, while the area signal Q is being input, the density data input from the marker removing section 262 is converted into standard density data of the color code determined by the marker color density determining section 263. This converted standard density data has a scan code of YM.
When it is either C, it becomes the standard density data of the color corresponding to the scan code, but when it is RGB, it is slightly different. The details are converted as shown in FIG. Dv is standard color density.

From the above, the selectors 24 and 2 in FIG.
When the first color reproduction processing section 22 is selected by 5,
Normal color reproduction processing is performed, and the color density of one pixel is expressed by YMC density and their combination or K density, and is output from the selector 25. When a black text part in a specific area of the document 15 is surrounded by markers MC of an arbitrary color, the standard color (YM
The area surrounded by the marker MC is color-converted to a standard density of one of the colors CKRGB. This converted color is a standard color with a constant density regardless of the shading of the marker.

Furthermore, when the second color reproduction processing section 23 is selected by the selectors 24 and 25, the color code output from the color code generation section 21 changes RGB→Y.
A conversion of MCK is performed. In other words, one pixel is YMCK
One color of RGB is determined. However, the density is determined by the density of the input pixel determined by RGB. Therefore, in this case, the recorded image becomes a mosaic image in which each pixel is one of the standard colors. Note that in this case as well, if a specific area is surrounded by a marker, the color within that area is converted to the standard color determined by the color code closest to the color of the marker, as described above.

[0024]

As described above, according to the present invention, since the color code is output as a code that identifies at least six colors of YMCRGB, by using this color code, in marker color conversion, the influence of the density of the marker can be reduced. As long as the same marker is used, the same color conversion will be performed. It is also possible to convert an input image into a mosaic image created using color codes and record it.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of main parts of a color image processing device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a marker color conversion section of the processing device.

FIG. 3 is an explanatory diagram of marker area detection.

FIG. 4 is a timing chart of marker area detection.

FIG. 5 is an explanatory diagram of marker color conversion.

FIG. 6 is a schematic configuration diagram of a conventional color image processing device.

FIG. 7 is a schematic explanatory diagram of marker color conversion.

Claims (3)

[Claims] 1. A color reproduction processing unit that converts an original image signal expressed in RGB to a recording color signal expressed in YMC, and a marker color that converts a marker area portion into a specific color corresponding to the marker color. The color image processing device includes a color code generation unit that creates a color code indicating the color of each pixel as at least one of six colors of YMCRGB from the original image signal. Characteristic color image processing device. 2. The color image processing device according to claim 1, wherein the marker color conversion section converts the marker area into one color determined only by the color code. 3. The color image processing device according to claim 1, wherein the color reproduction processing section converts a recording color signal of a pixel into a signal of one color determined only by the color code.