JP3185926B2 - Image processing apparatus and image processing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and an image processing method for reading a document image and outputting it as an image having a predetermined magnification.

[Conventional technology]

Conventionally, in a color image input / output device, one
To obtain one copy, the original is scanned four times, and a yellow (Y) signal is output according to each ratio of blue (B), green (G), and red (R) read in the first scan, for example. A yellow toner image is reproduced, and a magenta (M) signal is output according to the ratio of each of the B, G, and R signals read in the second time, the magenta toner is reproduced, and B, G, A cyan (C) signal is output according to the ratio of the R signal, and a cyan toner image is reproduced.
Black (BK) is output according to the ratio of the G and R signals, a black toner image is reproduced, and a full-color image is created by superimposing the Y, M, C, and BK toner images.

[Problems to be solved by the invention]

2. Description of the Related Art Conventionally, in order to satisfactorily reproduce an edge region of a black character, which is a characteristic region in an image, image recording is performed using only a black agent. When reading an enlarged document, the moving speed of the scanning system is slowed down. However, due to the resulting vibration of the scanning system, it is impossible to obtain an edge region of black characters with high accuracy, and it is not possible to obtain an image with good reproducibility. There was a problem.

An object of the present invention is to provide an image processing apparatus and an image processing method that solve the above-mentioned problems.

[Means for solving the problem]

An image processing apparatus according to the present invention is an image processing apparatus that forms a multicolor image by combining a plurality of color images, and performs a scaling process on a document image, regardless of the scaling ratio of the scaling process. A first reading method for reading a document image at a constant reading speed and extracting edge portion data of a predetermined color of the document image; and reading a document image for each color image at a reading speed corresponding to the scaling factor of the scaling process. Reading means for reading a document image by a second reading method for generating each color image signal corresponding to the magnification, and storage means for storing edge portion data of a predetermined color extracted by the first reading method Scaling means for scaling the edge portion data of the predetermined color stored by the storage means in accordance with the scaling factor; and reproducing the color image signals generated by the second reading method. To double means The scaled predetermined color portion corresponding to the edge portion data of Ri, and has a processing means for prohibiting the reproduction of the color image signals of other than the predetermined color.

Further, in the image processing method for forming a multi-color image by combining a plurality of color images, when performing a scaling process on a document image, the document image is processed at a constant reading speed regardless of the scaling factor of the scaling process. Reading a predetermined color edge portion data of the original image, storing a predetermined color edge portion data extracted in the first reading step, and A second reading step of reading a document image for each color image at a reading speed corresponding to the scaling factor and generating each color image signal corresponding to the scaling factor; A scaling step of scaling according to the scaling factor, and reproducing the color image signals generated in the second reading step, corresponding to edge portion data of a predetermined color scaled in the scaling step. In the part, Those having a process of prohibiting the reproduction of color image signals other than the color.

〔Example〕

FIG. 1 is a block diagram illustrating a configuration of a color image processing apparatus and a color image reading apparatus to which a color image processing method according to an embodiment of the present invention can be applied. Perform signal processing. Reference numeral 202 denotes a printer unit, and an image scanner unit 2
This portion prints out an image corresponding to the document image read at 01 on a sheet in full color.

In the image scanner unit 201, reference numeral 200 denotes a mirror surface pressure plate, and an original 204 on an original platen glass (hereinafter, platen) 203
Irradiated by a lamp 205, guided to mirrors 206 to 208, an image is formed on a three-line sensor (for example, composed of a charge-coupled device such as a CCD) 210 by a lens 209, and full-color information red (R) and green (G ) And blue (B) components to the signal processing unit 211. The lamp 205, mirror 206
Is the speed v, and the mirrors 207 and 208 scan the entire surface of the original by mechanically moving at 1 / 2v in the direction perpendicular to the electrical scanning direction of the line sensor. The signal processing unit 211 electrically processes the read signal, decomposes the signals into magenta (M), cyan (C), yellow (Y), and black (BK) components, and sends them to the printer unit 202. In addition, for one document scan in the image scanner unit 201, one component of M, C, Y, and BK is sent to the printer unit 202, and one printout is completed by a total of four document scans.

M, C, M or sent from the image scanner unit 201
The BK image signal is sent to the laser driver 212. The laser driver 212 modulates and drives the semiconductor laser 213 according to the image signal. The laser light is reflected by the polygon mirror 214 and the fθ lens 21.
5. Scan the photosensitive drum 217 via the mirror 216.

Reference numeral 218 denotes a rotary developing unit, which includes a magenta developing unit 219, a cyan developing unit 220, a yellow developing unit 221, and a black developing unit 222. The four developing units alternately contact the photosensitive drum 217 and are formed on the photosensitive drum 217. The developed electrostatic latent image is developed with toner.

A transfer drum 223 wraps the paper fed from the paper cassette 224 or the paper cassette 225 around the transfer drum 223, and transfers the image developed on the photosensitive drum 217 to the paper.

After the four colors M, C, Y, and BK are sequentially transferred in this manner, the sheet passes through the fixing unit 226 and is discharged.

More specifically, the color image read from the document reading means (the reading section 101 in this embodiment) by an extracting means (by a color determining section 124, an edge determining section 127, an AND gate 129, etc., described later) provided in the signal processing section 211. When the information is analyzed and a predetermined color portion (black edge portion data in this embodiment) in the color document image is extracted, the extracted black edge portion data is provided in a storage unit (in this embodiment, provided in the reader unit). RAM120) at least until the next read,
It is possible to extract all image information reproduced in black in a color image as color image information developed only with a black developing material.

Further, the prohibiting means (CPU unit 113) prohibits the transmission of the color image signal when the extraction means extracts the black edge portion data determined to be black by color separation, and sends the non-black image data to the corresponding edge area. Reproduction by the color developing material is restricted, and the corresponding edge region is reproduced preferentially by the black developing material only in the printer unit.

Further, the contents of the storage means are retained until the color development processing for the designated number of image formations is completed, and the black priority development processing is continuously performed based on the black edge portion data fixedly stored in the storage means. And stabilizes the color of the reproduced color image.

Until the color development processing for the designated number of image formations is completed, the prohibition unit continuously prohibits the transmission of each color image signal to the printer unit and stabilizes the color of the reproduced color image.

FIG. 2 is a control block diagram for explaining a detailed configuration of the signal processing unit 211 shown in FIG.
A color sensor that can independently obtain analog color signals of (red), G (green), and B (blue), an amplifier for amplifying each color, and an A / D converter for converting it to an 8-bit digital signal. Having. The signal subjected to shading correction for each color by the shading correction unit 102 is corrected for a shift between pixels of each color by a shift memory unit 103, and a color determination unit 124 described later and a LOG conversion unit for performing logarithmic correction for light / density conversion. Sent to 104. The density signals yellow (Y), magenta (M),
Cyan (C) is input to the black generation unit 105, and a black signal (BK)
Is generated. The black signal (BK) is generated by MIN (Y, M, C). Further, the masking / UCR unit 106 corrects the filter characteristics and toner density characteristics of the color sensor for the Y signal, M signal, C signal, and BK signal output from the black generation unit 105, and corrects the four colors after undercolor correction. One of the signals to be developed is selected. Next, after the density conversion is performed by the density conversion unit 107 in accordance with the development characteristics of the printer and the operator's preference, the trimming processing unit edits a desired section, and then sends it to the printer unit to form an image.

The synchronization signal generation unit 109 includes a horizontal synchronization signal (BD beam detect) and a vertical synchronization signal IT sent from the printer unit.
Based on the OP (image top), a horizontal synchronizing signal HSYNC or a pixel synchronizing signal CLK used inside the image scanner is generated and sent to each processing unit or CPU.

The CPU unit 113 includes a well-known I / O circuit, a timer circuit, an interrupt control circuit, a serial communication circuit,
It has an OM, a RAM, etc., and controls the above-described processing units. Also, CP
The U unit 113 controls a pulse motor that drives the optical system, a document illumination lamp, a sensor that detects the position of the optical system, and an operation unit.

Hereinafter, the black edge region processing will be described with reference to FIGS. 3 (a) to 3 (e).

FIGS. 3A to 3E are flowcharts for explaining an example of a black edge region processing procedure in a color image processing apparatus and a color image reading apparatus to which the color image processing method according to the present invention can be applied. (1) to (68) indicate each step.

The RAM 120 shown in FIG. 2 reads (297 × 16) × (210 × 16) = 1195840, for example, for reading and storing an A4 size document (297 mm × 210 mm) at 16 pels per mm.
It has a bit memory capacity.

First, the process waits until a copy button (not shown) on the operation unit 117 is pressed (1). When the copy button is pressed, the CPU unit 113 detects this and outputs a reset signal 121 to output a sub-scan counter. After setting the values of 133 and the main scanning counter 132 to zero (2), the prescan operation of the scanner unit and the printer unit is started (3).

The R, G, and B image signals read by the reading unit 101 in synchronization with the reading clock CLK with reference to the BD signal (4) are output from the shading correction unit 102, the shift memory unit 103, and the LOG conversion unit 1
04, color determination unit 124 as C, M, Y signals via black generation unit 105
Enter The color determination unit 124 determines whether the difference between the maximum value and the minimum value of the 8-bit C, M, and Y signals is, for example, 7 or less (black) (5). Is output.

On the other hand, the M signal 126 is also input to the edge determination unit 127.
The edge determination unit 127 has a built-in FIFO memory, and determines whether or not the value does not match (edge) one pixel before and after the target pixel in the main scanning direction and one pixel before and after in the sub-scanning direction (6).
If YES, AND gate 1 with edge signal 128 and black signal 125
Enter in 29. Thus, the signal 130 is output from the AND gate 129 only when the read pixel is black and at the edge. As a result, the write control signal R / W
Becomes low level (7), "1" is stored in the address "000000 _H " of the RAM 120 (8). Similarly, the main scanning counter 132 counts up (10) in synchronization with the clock signal 131 (9), so the AND gate 129
Are stored sequentially until 1290H.

On the other hand, in the case of NO in steps (5) and (6), when the write control signal R / W becomes H level (11), "00000
0 _H "and" 0 "is stored in (12), returns to the step (9).

On the other hand, the sub-scanning counter 133 clears the main scanning counter 132 (14) every time the BD signal 134 changes from the L level to the H level (14), and synchronizes with the sub-scanning counter 1 in synchronization with the BD signal 134.
Since 33 is counted up (15), the black edge portion of the entire surface of the A4 size document is stored in the RAM 120. Next, it is determined whether or not the sub-scanning counter 133 overflows (16). If NO, the process returns to step (4).
If YES, enter the image playback mode and select 1 after prescan.
The second original scanning is performed. At this time, the CPU 113 sets the switching signal to the L level (17), and outputs the reset signal 121 to clear the output of the sub-scanning counter 133 and the main scanning counter 132 ("0") (18). Next, the write control signal 137 is set to the “H” level (19), and the BD signal 134 and the ITOP signal
Synchronize with the read clock CLK based on 135
The first image signal from 101 is a shading converter 102,
The C / M / Y / BK signals are sequentially input to the masking / UCR unit 106 via the shift memory unit 103, the LOG conversion unit 104, and the black generation unit 105 (20).

At this time, the CPU 113 makes the masking / UCR unit 106 output the C 'signal masked / UCR by the bus 136a. The C ′ signal is subjected to density correction according to the toner in the density conversion unit 107 and output from the density conversion unit 107. At this time, the sub-scanning counter 133 and the main-scanning counter 132 indicate “000000 _H ”, and the write control signal 137 indicates “H”.
Since it is at the level, the data DATA stored during the prescan is read from the RAM 120. At this time,
The CPU 113 sets the switching signal 138 to L level (C, M, Y
L level when playing back, H level when playing back BK)
The signal read from the RAM 120 is inverted by the inverter 139 and then input to the AND gate 136. In other words, at the time of pre-scanning, if "1" is stored in "000000 _H " of the RAM 120 and "1" is stored in "000000 _H " of the RAM 120 (21), the "L" level is input to the AND gate 136, so the video signal Is prohibited (22), and if "0" is input to "000000 _H " of the RAM 120, the video signal is transmitted to the printer unit (23).

Next, when the read clock changes from "L" level to "H" level (24), the main scanning counter 132 counts up (25), and the BD signal 134 changes from "L" level to "H" level.
When the level reaches (26), the main scanning counter 132 is cleared (27), and the sub-scanning counter 133 is counted up (2
8) It is determined whether or not the sub-scanning counter 133 overflows (29). If NO, the process returns to step (20), and YES, that is, the image of the entire A4 document is synchronized with the cyan (C) toner in synchronization with the clock signal 131. Has been completed, and the steps (30) to (42) shown in FIG.
To perform image reproduction processing for magenta,
Similarly, the respective steps (43) to (55) shown in FIG. 3D are executed to execute the image reproduction processing for yellow, and then, through the respective step processings shown in FIG. Executes image reproduction processing for black (BK).

At that time, in step (60), the address 0000 of the RAM 120
If “1” is stored in _H , the switching signal 138 of the CPU unit 113 has been set to the “H” level in step (56), so that it is input to the AND gate 136 through the non-invert gate 140. Therefore, the output of the density conversion unit 107 is sent to the printer unit as it is. In other words, where the edge portion is determined at the time of the pre-scan, the color toner is not completely applied and the image is reproduced only with the black toner, so that black without color blur is reproduced together with the other developed colors.

In addition, the enlargement copy processing of the digital color image reading apparatus does not read the image by enlarging with a zoom lens like the enlargement processing of the analog color image reading apparatus,
Enlargement in the main scanning direction is performed by reading one pixel a plurality of times, for example,
In the case of 400% enlargement, writing is performed four times, and enlargement in the sub-scanning direction is performed by setting the speed of the printer to the same as at the same magnification, and reading by setting the sub-scanning speed of the reader to 1/4.
If a stepping motor is used as the power source for scanning,
Due to the vibration of the stepping motor at the time of low-speed driving, the same point of the document cannot be read as the same point more frequently than in the case of the same magnification by a plurality of scans.

Therefore, at the time of pre-scanning, the sub-scanning is performed at the same speed as that of the same magnification to store the black edge area, and when reproducing the image, the sub-scanning counter is counted up every time the BD signal 134 is input four times. If an image is reproduced by using the same method, it is possible to reproduce an enlarged black image which is sharper than at the time of equal magnification.

For example, at the time of 400% enlargement copy, the black edge area is stored while counting up the sub-scanning counter at four times the frequency of the BD signal 134, and at the time of reading, the sub-scanning counter is counted up by the BD signal 134. If the black edge area is read, it is possible to suppress the oblique straight line generally occurring at the time of enlarged copy from being reproduced in a stepwise manner.

Further, in the above embodiment, the information of the black edge area is stored as simple binary data in the RAM 120 as “1” or “0”.
Has been described, but this may be stored as multi-valued data.

〔The invention's effect〕

As described above, according to the present invention, in an image processing apparatus that forms a multi-color image by combining a plurality of color images, when performing scaling processing on a document image, A first reading method for reading an original image at a constant reading speed regardless of the original image, and extracting an edge portion data of a predetermined color of the original image; Reading means for reading a document image by a second reading method for reading each time and generating each color image signal corresponding to the magnification, and storing edge part data of a predetermined color extracted by the first reading method Storage means for performing scaling, scaling means for scaling edge portion data of a predetermined color stored by the storage means in accordance with the scaling factor, and reproducing each color image signal generated by the second reading method. , Said strange Means for prohibiting reproduction of image signals of colors other than the predetermined color in a portion corresponding to the edge portion data of the predetermined color scaled by the means. It is possible to extract color edge portion data, and as a result, it is possible to obtain a highly accurate scaled image by processing an image signal according to the highly accurate predetermined color edge portion data.

Further, in the image processing method for forming a multi-color image by combining a plurality of color images, when performing a scaling process on a document image, the document image is processed at a constant reading speed regardless of the scaling factor of the scaling process. Reading a predetermined color edge portion data of the original image, storing a predetermined color edge portion data extracted in the first reading step, and A second reading step of reading a document image for each color image at a reading speed corresponding to the scaling factor and generating each color image signal corresponding to the scaling factor; A scaling step of scaling according to the scaling factor, and reproducing the color image signals generated in the second reading step, corresponding to edge portion data of a predetermined color scaled in the scaling step. In the part, And a processing step of prohibiting the reproduction of image signals of colors other than the color, so that it is possible to accurately extract the edge portion data of a predetermined color of the original image regardless of the magnification, and as a result, this highly accurate By processing the image signal in accordance with the edge part data of the predetermined color, it is possible to obtain a highly accurate scaled image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of a color image processing apparatus and a color image reading apparatus to which a color image processing method according to an embodiment of the present invention can be applied, and FIG. 2 is a signal processing apparatus illustrated in FIG. 3 (a) to 3 (e) are control block diagrams for explaining the detailed configuration of the section, and FIG. 3 (a) to FIG. It is a flowchart explaining an example. In the figure, 101 is a reading unit, 102 is a shading correction unit, 10
3 is a shift memory unit, 104 is a LOG conversion unit, 105 is a black generation unit,
106 is a masking / UCR unit, 107 is a density conversion unit, 109 is a synchronization signal generation unit, 113 is a CPU unit, 117 is an operation unit, 120 is RAM, 124
Is a color determination unit, 127 is an edge determination unit, 129 and 136 are AND gates, 132 is a main scanning counter, 133 is a sub-scanning counter, 211
Is a signal processing unit.

Continuation of the front page (56) References JP-A-1-200964 (JP, A) JP-A-63-292770 (JP, A) JP-A-3-309566 (JP, A) JP-A-1-233396 (JP) , A) JP-A-1-194665 (JP, A)

Claims (2)

(57) [Claims] In an image processing apparatus for forming a multicolor image by combining a plurality of color images, when performing a scaling process on a document image, a fixed reading speed is set regardless of the scaling factor of the scaling process. A first method for reading an original image by extracting a predetermined color edge portion data of the original image
The original image can be read by the second reading method of reading the original image for each color image at a reading speed corresponding to the magnification of the magnification processing and generating each color image signal according to the magnification. Reading means; storage means for storing edge part data of a predetermined color extracted by the first reading method; and scaling of edge part data of a predetermined color stored by the storage means in accordance with the scaling factor. When reproducing each color image signal generated by the second reading method, a portion corresponding to edge portion data of a predetermined color scaled by the scaling portion includes a portion other than the predetermined color. An image processing apparatus comprising: processing means for prohibiting reproduction of a color image signal. 2. An image processing method for forming a multi-color image by combining a plurality of color images, wherein, when performing a scaling process on a document image, a constant reading speed regardless of the scaling factor of the scaling process. A first method for reading an original image by extracting a predetermined color edge portion data of the original image
Reading step; storing a predetermined color edge portion data extracted in the first reading step; and reading a document image for each color image at a reading speed corresponding to a scaling factor of the scaling process. A second reading step of generating each color image signal according to the scaling factor; a scaling step of scaling the edge portion data of a predetermined color stored in the storage step in accordance with the scaling factor; When reproducing each color image signal generated in the reading step, the reproduction of the image signal of a color other than the predetermined color is prohibited in a portion corresponding to the edge portion data of the predetermined color scaled in the scaling step. An image processing method, comprising: a processing step.