JPH0622126A - Picture reader - Google Patents

Abstract

PURPOSE:To reduce the processing time by correcting density information formed through the use of one color among three primary colors by each color based on color information generated from three-primary color data so as to decrease the scale of a circuit generating the density information from read data. CONSTITUTION:R, G, B data after position deviation correction are inputted to a hue discrimination section 41, and since the spectral sensitivity of the G data is close to a human specific sensitivity, the data G are used for input density data and outputted together with a color code generated by data R-B, R-G obtained through subtraction processing. A color code is corrected by a ghost cancel section 42 to form an input color code and it is inputted to a density correction section 45 together with input density data and an area signal 48. The correction section 45 sets output density data with respect to input density data for each input color to correct a change in a density balance. Thus, the scale of the generating circuit of the density information is reduced and the processing time is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device for reading a color image using an image sensor.

[0002]

2. Description of the Related Art In an image input / output system such as a digital copying machine, an image reading device for reading a color image using, for example, a color image sensor is used as its input means. In an image reading apparatus that handles a color image in this way, there are three types of red (hereinafter referred to as R), green (hereinafter referred to as G), blue (hereinafter referred to as B), etc. obtained by the image sensor. The primary color data is HCV,
Data processing such as conversion to color data such as XYZ and L ^* a ^* b ^* to generate color information and density information is performed.

[0003]

However, the calculation for conversion to the color system as described above requires multiplication or exponentiation, the circuit scale for the calculation is large, and the calculation time is long. There is a problem that it will become.

Further, as shown in FIG. 20, an image sensor 5 in which B, G and R pixels are arranged side by side in the main scanning direction.
When 01 is used, the actual document reading position is deviated depending on each color of B, G, and R, so that an erroneous determination occurs when determining the color of the image 502. So R,
It is necessary to perform correction so that the reading positions of G and B become the same virtual point 503. As an example of this correction, R and B data are calculated by calculating data of R and G pixels on the left and right of G with reference to the G position. This correction will be described with reference to FIG. 20.
4 of R, G, the original data each R _n of B, G _n, B
_n , and the corrected data are R _n ′, G _n ′, and B, respectively.
_In the case of _n ', _Gn ' uses _Gn as it is,
It means that R _n ′ is determined by the calculation of R _{n − 1} and R _n, and B _n ′ is determined by the calculation of B _n and B _{n + 1} .

However, if the density of each pixel is calculated using the corrected data calculated in the above calculation, the density of one pixel is determined based on the data of a plurality of pixels, and therefore the resolution However, there is a problem in that

Therefore, an object of the present invention is to provide an image reading apparatus capable of reducing the circuit scale and processing time when generating density information from read data.

Another object of the present invention is to obtain read data by using an image sensor in which light receiving portions of three primary colors are arranged side by side in the main scanning direction, and to receive the read data, light receiving portions of respective colors are obtained. An object of the present invention is to provide an image reading apparatus capable of improving the resolution when performing the process of correcting the shift of the.

[0008]

According to another aspect of the present invention, there is provided an image reading apparatus which reads a document and obtains three primary color data for each pixel, and a reading unit which obtains three primary color data.
Density information generating means for generating density information for each pixel using data of one color of the primary color data, and color information generating means for generating color information for each pixel using the three primary color data obtained by the reading means. And density correction means for correcting the density information generated by the density information generation means for each color based on the color information generated by the color information generation means.

In this image reading apparatus, the reading means obtains the three primary color data for each pixel, and the density information generating means generates the density information for each pixel using the data of one color among the three primary color data, and the color information is generated. 3 by information generation means
Color information for each pixel is generated using the primary color data. Further, the density information is corrected for each color by the density correction means based on the color information.

An image reading apparatus according to a second aspect of the present invention is the image reading apparatus according to the first aspect, wherein the reading means uses an image sensor in which light receiving portions for each of the three primary colors are arranged side by side in the main scanning direction. The original is read.

An image reading apparatus according to a third aspect of the invention is the image reading apparatus according to the first or second aspect of the invention, in which the reading means obtains data of three primary colors of red, green and blue as the three primary color data. The means uses the green data to generate density information.

The image reading apparatus according to the fourth aspect of the invention is 3
A reading unit that obtains three-primary-color data for each pixel by reading an original using an image sensor in which light-receiving units for each of the primary colors are arranged side by side in the main scanning direction, and a reading position of one of the three primary colors is used as a reference. In order to virtually match the reading positions of the other two colors with the reference reading position, the data for each pixel of the other two colors is corrected by calculation using the data of a plurality of pixels for that color. Position deviation correcting means, density information generating means for generating density information for each pixel using the data of one color serving as the reference of the reading position in the position deviation correcting means, and the position deviation correcting means after correcting the position deviation correcting means. Color information generating means for generating color information for each pixel using the three primary color data, and density information generated by the density information generating means for each color based on the color information generated by the color information generating means. Those having a positive to density correction means.

In this image reading apparatus, the reading means obtains the three primary color data for each pixel by using the image sensor in which the light receiving portions for each of the three primary colors are arranged side by side in the main scanning direction, and the positional deviation correction means 1 of 3 primary colors
The color reading position is used as a reference, and other 2
The data of the other two colors are corrected in order to virtually match the color reading positions. Then, the density information generation unit generates the density information for each pixel by using the data of one color which is the reference of the reading position, and the color information generation unit generates the color information for each pixel by using the corrected three primary color data. Is generated. Further, the density information is corrected for each color by the density correction means based on the color information.

An image reading apparatus according to a fifth aspect of the present invention is the image reading apparatus according to the fourth aspect, wherein the reading means obtains data of the three primary colors of red, green and blue as the three primary color data, and the positional deviation correction means. Is for correcting data of the other two colors with reference to the green reading position, and the density correcting means is for generating density information using the green data.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 19 relate to an embodiment of the present invention, and this embodiment is an example in which the present invention is applied to a digital copying machine.

The digital copying machine of the present embodiment reads an original with a full-color image sensor and performs various image processings.
The image scanner unit is equipped with a page memory for storing image data that has undergone image editing, and a printing unit for printing the image data stored by the image scanner unit in two colors. The image scanner unit is provided with a control panel for the user to specify the number of copies and various image processing / editing functions, etc. The desired copy can be obtained by this control panel specification. There is.

FIG. 1 is a block diagram showing the arrangement of the image scanner section. The image scanner unit 220 has an image sensor 308 using a charge coupled device (hereinafter, referred to as CCD), and the image sensor 308 is mounted on the CCD drive circuit 200. The analog circuit 201,
Video (1) circuit 202, video (2) circuit 203, color circuit 204, digital filter circuit (hereinafter referred to as DF
Described as a circuit. ) 206 and halftone processing circuit (hereinafter H
It is described as a TP circuit. ) 207 is provided. An area recognition circuit (hereinafter, referred to as an AR circuit) 205 is connected to the color circuit 204, and an editing circuit (hereinafter, referred to as an EDIT circuit) 208 is connected to the HTP circuit 207. Also, the video (1) circuit 202 to the HTP circuit 20
7, an AR circuit 205, an EDIT circuit 208, and a central processing unit (hereinafter, referred to as a CPU) that controls them.
(1) The circuit 209 is connected to each other by the VME bus 16 which is one of the system bus standards. The circuits 202 to 209 are the image processing unit 214.

A data processing circuit 210 is connected to the latter stage of the HTP circuit 207. This data processing circuit 210
Includes a CPU (2) circuit 211 and a page memory circuit 2
12 are connected. In addition, the CPU (2) circuit 211
A control panel 213 is connected to the. The data processing circuit 210 outputs the image data 215 to the printing section and inputs the control signal 238 from the printing section. In addition, the CPU (2) circuit 211
Is the CPU (1) circuit 209 via the control data line 120.
And the control unit of the printing unit via the control data line 237.

FIG. 2 is a block diagram showing the structure of the printing unit. The print unit 221 is the image scanner unit 22.
Data separation unit 23 for inputting image data 215 from 0
1 and the first provided in the latter stage of the data separation unit 231.
The color image data memory 232 and the second color image data memory 234, the first color laser driving section 233 provided in the latter stage of the first color image data memory 232, and the latter stage of the second color image data memory 234 are provided. A second color laser drive unit 235 and a control unit 236 that controls each of the above units are provided. The control unit 236 is connected to the CPU (2) circuit 211 of the image scanner unit 220 via the control data line 237 and sends a control signal 238 to the data processing circuit 210 of the image scanner unit 220. .

FIG. 3 is an explanatory view showing a part of the cross section of the image scanner section. The image scanner unit includes a plurality of document feed rollers 302 provided on the upper side of the document feeding path,
303, and a plurality of rollers 304 and 305 provided below the document feeding path and nipping the document 310 together with the document feed rollers 302 and 303. A platen glass (not shown) is provided on the lower side of the document transport path, and a platen roller 311 is provided on the platen glass. Further, a light source 306 below the platen glass, an image sensor 308 mounted on the CCD drive circuit 200, and a converging rod lens for forming an image of an original 310 illuminated by the light source 306 on the image sensor 308. An array 309 is provided. In addition, a sensor 301 that detects the document 310 is provided in the document insertion portion. In addition, the platen roller 311
Has a plurality of flat surfaces around the platen roller 311
A reference plate 312 is provided which is rotatable around the central axis of. As shown in FIG. 4, the reference plate 312 has a black surface 313 serving as a black level reference and a white surface 314 serving as a white level reference. The black surface 313 and the white surface 314 are connected to the platen glass. And the platen roller 311 can be selectively interposed.

FIG. 5 is a plan view of the image sensor 308. The image sensor 308 used in the present embodiment is a full-color contact type sensor, and as shown in FIG. 5, five line type sensor chips (1) to (1) arranged in a zigzag pattern.
(5) 321 to 325 are included. Sensor chips (1), (3), (5) and sensor chips (2), (4)
And are spatially displaced by Δx. Therefore, the image data read by the image sensor 308 is stored in two chip groups (sensor chips (1), (3), (5) and sensor chips (2), (4)) at different portions on the document. The data will be read at the same time. A process of converting this data into data obtained by reading the same line of the original is performed in the video (1) circuit 202 described later. In this embodiment, three image sensors 308 shown in FIG. 5 are arranged in a zigzag pattern in order to read a wide original, and these three image sensors 308 are attached so as to read the same line of the original.

FIG. 6 is an explanatory view showing the pixel arrangement of one chip of the image sensor 308. Image sensor 30
A pixel 8 for each color having B, G, and R color filters as three primary colors is arranged in the order of B, G, and R.

Next, of the circuits of the image scanner section 220, the configuration and operation of the part particularly related to this embodiment will be described.

FIG. 7 is a block diagram of the CPU (1) circuit 209. The CPU (1) circuit 209 includes the CPU 111,
Timer 112, read only memory (hereinafter ROM
Is written. ) 113, random access memory (hereinafter referred to as RAM) 114, VME bus interface (hereinafter referred to as VME bus I / F) 115, output control section 116, input control section 117 and serial communication section 1
18, which are connected to each other by a bus. The VMEbus I / F 115 is connected to the VMEbus 16 and the serial communication unit 118 is connected to the control data line 120. The CPU (1) circuit 209 is a RAM 1
By executing the program stored in the ROM 113 by using 14 as a work area, the image processing unit 214
It controls each circuit therein and communicates with the CPU (2) circuit 211.

In FIG. 1, when the user designates the desired number of copies and various image processing / editing operations from the control panel 213, the CPU on the CPU (2) circuit 211 passes through the control data line 120 on the CPU (1) circuit 209. The CPU 111 sends various image processing / editing information selected on the control panel 213. Also,
The CPU on the CPU (2) circuit 211 sends information such as the paper size selected by the control panel 213 to the control unit 236 of the printing unit 221 through the control data line 237.

In FIG. 7, various image processing / editing information sent through the control data line 120 is taken into the CPU (1) circuit 209 via the serial communication unit 118 and decoded by the CPU 111. CPU111
Displays various parameters (control data) corresponding to image processing / editing information on the VMEbus I / F 115 and VMEbus 16
It is set in a predetermined register or RAM of each circuit 202 to 208 in the image processing unit 214 through.

Next, in FIG. 3, when the document 310 is inserted into the image scanner section 220, the sensor 301 is turned on, which is detected by the CPU 111 through the input control section 117 of the CPU (1) circuit 209 in FIG. A motor for document feeding is driven, and the document 310 is conveyed by the document feed rollers 302 and 303. When the conveyed document 310 reaches the platen roller 311, the light source 306
The image sensor 3 driven by the CCD drive circuit 200 as shown in FIG.
The original image is read by 08, and the CCD video signal 9
Are sequentially processed by the analog circuit 201.

FIG. 8 is a block diagram of the analog circuit 201. The analog circuit 201 is the CCD drive circuit 20.
A sample and hold unit 1 for extracting an effective image signal from a CCD video signal 9 from 0, a gain control unit 2, a dark correction unit 3, an offset control unit 4, and an analog-unit, which are provided in sequence after the sample and hold unit 1. Digital / analog conversion (hereinafter referred to as D / A conversion) data from the digital conversion (hereinafter referred to as A / D conversion) unit 5 and the video (1) circuit 202 is D / A.
It has a D / A converter 6 which converts and sets the gain controller 2 and the offset controller 4.

Prior to reading the original, when the power of the image scanner unit 220 is turned on, the black surface 313 of the reference plate 312 shown in FIG. 4 is exposed on the platen glass and read, and the read value at this time becomes a predetermined value. As described above, the offset value of the offset control unit 4 is set to the CPU 11
1 to the D / A converter 6 is automatically set (hereinafter, this is referred to as automatic offset control: AOC). Next, on the platen glass, the reference plate 3 shown in FIG.
The white surface 314 of 12 is read and read, and the gain value of the gain control unit 2 is changed from the CPU 111 to the D / A conversion unit 6 so that the read value at this time becomes a predetermined value.
Is automatically set (hereinafter, this is referred to as automatic gain control: AGC). Since such adjustment is performed in advance, the actual document reading data becomes video data having a sufficient dynamic range without being saturated, and is digitized by the A / D conversion unit 5 to obtain the image data 8. The video data is sequentially sent to the video (1) circuit 202. The dark correction unit 3 is a unit that removes an output change due to a dark current of the image sensor 308 by using an output signal of a shield bit (light-shielded pixel) of the image sensor 308.

FIG. 9 is a block diagram of the video (1) circuit 202. The video (1) circuit 202 is an analog circuit 2
A CCD gap correction unit 11 for inputting image data 8 from 01, an RGB separation unit 12 and a dark shading correction unit 13 which are sequentially provided at a subsequent stage of the CCD gap correction unit 11, and control for controlling the respective units 11 to 13 It includes a unit 14 and a clock generation unit 15 that supplies a clock to each of the units 11 to 13. The control unit 14 is V
It is connected to the ME bus 16 and sends the D / A conversion data 7 to the analog circuit 201 via the VME bus 16 and outputs the control signal 19 to the video (2) circuit 203 in the subsequent stage. ing. The clock generator 15 sends a drive clock 20 to the analog circuit 201, and the drive clock 20 is sent to the CCD drive circuit 200 via the analog circuit 201.

As described above, the image sensor 308 used in this embodiment is composed of five chips 321 to 325 arranged in a staggered pattern as shown in FIG. 5, and the two chip groups are displaced by Δx. Therefore, the CCD gap correction unit 11 performs a process of converting the data read by the two chips into the data read on the same line of the original. In the CCD gap correction unit 11, specifically, the data read by the chips (2) and (4) 322 and 324 is delayed by using a memory and is converted into read data of the same line. The output pixel data string of the CCD gap correction unit 11 is a series of B, G, and R data, as shown in FIG. 10, which is shown in FIG.
As shown in (c) to (c), the RGB separation unit 12 performs the process of converting the pixel data sequence into R, G, and B. The pixel data separated into R, G, and B in this way is sequentially sent to the dark shading correction unit 13, and dark shading correction is performed. The dark shading correction is performed after the AOC and AGC operations are performed when the power of the image scanner unit 220 is turned on before the reading of the original, and then the black surface 313.
Is a process of storing the read image data in the memory for each pixel, and subtracting the black surface read data stored for each pixel from the image data of each pixel when the document is actually read. The image data 18 thus sequentially processed by the video (1) circuit 202 is sent to the video (2) circuit 203.

FIG. 12 is a block diagram of the video (2) circuit 203. The video (2) circuit 203 uses the video (1)
The bright shading correction unit 21 that inputs the image data 18 from the circuit 202, and the bright shading correction unit 21.
RGB misalignment correction unit 22, sensor misalignment correction unit 24, and data block division unit 2 which are sequentially provided in the subsequent stage.
5, a control unit 26 for controlling each of the units 21 to 25, and a clock generation unit 27 for supplying a clock to each of the units 21 to 25. The control unit 26 is connected to the VME bus 16, inputs the control signal 19 from the video (1) circuit 202, and sends the control signal 30 to the color circuit 204. Further, the clock generator 27 sends the control clock 28 to each circuit in the subsequent stage.

The image data 18 sent to the video (2) circuit 203 is first subjected to bright shading correction by the bright shading correction section 21. Similar to the dark shading correction, the bright shading correction stores the image data obtained by reading the white surface 314 in the memory for each pixel after the AOC and AGC operations, and the image data of each pixel when the original is actually read. Is a process for normalizing (dividing) with the white surface read data for each pixel stored.
The image data that has been subjected to the light shading correction and the dark shading correction becomes image data that is not affected by the light amount distribution of the light source 306 or the sensitivity variation of each pixel. Further, the offset value and gain value of AOC and AGC can be set by the CPU 111, and the memories of the light shading correction unit 21 and the dark shading correction unit 13 can be read and written by the CPU 111 via the VME bus 16. , AGC and control of bright and dark shading correction by CPU11
One can do it.

The image used in this embodiment
The sensor 308, as shown in FIG.
(Light sections) are arranged side by side in the main scanning direction, and each of B, G, and R
1 pixel in read data by combining 1 pixel
Are configured. Therefore, the image sensor 308
If the original is scanned by, each of B, G, and R colors
The actual reading position is deviated. As a result, the image
At the edge part of, the color is judged by the color circuit 204 in the next stage.
If you do, you will make a wrong decision and it will be a so-called color ghost.
Will be reproduced. So, read B, G, R
It is necessary to correct the positions so that they become the same virtual point. this
The RGB misregistration correction unit 22 performs the correction. Real
RGB misregistration correction in the embodiment is performed with a G image with high sensitivity.
Assuming that the prime position is a virtual point as a reference position, R and B
The value at the virtual point is calculated. For example in Figure 6
Denotation of each pixel of B1 to B3, G1 to G3, R1 to R3 shown
B for each₁~ B₃, G₁~ G₃, R₁~ R₃When
Then, B1 to B3, G1 to G3 after the RGB positional deviation correction,
The data of each pixel of R1 to R3 is set to B₁′ 〜
B ₃′, G₁'~ G₃′, R₁'~ R₃’G
₂′, B₂′, R₂′ Is calculated according to the following formula
Therefore, it is required.

[0035]

## EQU1 ## G ₂ ′ = G ₂ B ₂ ′ = (2B ₂ + B ₃ ) / 3 R ₂ ′ = (R ₁ + 2R ₂ ) / 3

This correction is performed for all pixels, and the corrected data is used for the hue judgment in the subsequent stage.

The explanation of the operation up to this point is given in the image sensor 3.
However, as described above, three image sensors 308 are actually used to read a wide original. These three image sensors 308 are adjusted and attached so that the same line of the original can be read, but in reality, a deviation occurs. The sensor position shift correction unit 24 corrects this shift. The sensor position deviation correction is almost the same as the CCD gap correction, and the image data of each sensor is delayed by an arbitrary time by using a memory, so that the image data of the three sensors is main-scanned on the original at the joint. The images are adjacent to each other in the same direction.

In the case of a high-speed wide-width digital copying machine, it is necessary to process image data at a high speed.
There is a limit to high-speed operation of digital integrated circuits and the like. Therefore, the output image data of the sensor displacement correction unit 24 is
The data block dividing unit 25 divides the block into a plurality of blocks in the main scanning direction. Here, for example, the output image data of one image sensor 308 is divided into two blocks, and the read data of the original 310 is divided into a total of six blocks as shown in FIG. Will be processed. The image data 29 thus divided into blocks is sequentially sent to the color circuit 204.

FIG. 14 is a block diagram of the color circuit 204. The color circuit 204 includes a hue determination unit 41 that inputs the image data 29 from the video (2) circuit 203, and a ghost cancellation unit 42, a buffer memory 43, and a color editing unit 44 that are sequentially provided at the subsequent stage of the hue determination unit 41. And a density correction unit 45, and a control unit 46 for controlling the above units 41 to 45. The control unit 46 is connected to the VME bus 16 and inputs the control signal 30 from the video (2) circuit 203 and the control signal 49 from the AR circuit 205 to the DF circuit 206 and the AR circuit 205. Control signals 50 and 51 are sent respectively.

The image data 29 input to the color circuit 204 are R, G, and B color image signals, and the hue determining unit 41 determines the color of the image on the original and inputs the coded color code signal. Density data and are generated.

Here, the hue judging section 41 will be described in detail. Conventionally, when determining the color code and the density from the R, G, B data, for example, the hue (H), the saturation (C), and the lightness (V) are obtained by calculating the R, G, B data. The color code was determined by the combination of the and saturation, and the density was determined by the lightness. To calculate the hue and saturation, the R-B axis and the R-B as shown in FIG.
The polar coordinates represented by the G axis are used. The saturation (C) is the center R of the coordinates (RB, RG) in this polar coordinate system.
-B = 0, determined by the distance from RG = 0, C
Is smaller, the saturation is lower, and as C is larger, the saturation is higher.
The hue (H) is determined by the angle of the line connecting the coordinates (RB, RG) and the center (0, 0) with respect to the RB axis, and the size of H determines the color of the image. Specifically, the saturation (C) and the hue (H) are calculated by the following formulas. Note that R, G, and B in the following equations are density data for each color.

[0042]

[Equation 2] C = √ {(R−B) ² + (R−G) ² } ... H = tan ⁻¹ {(R−G) / (R−B)}

Colors with low saturation are white or black, that is, achromatic. The range of achromatic colors differs depending on the color.
In other words, the combination of H and C determines whether the color is achromatic or chromatic. Then, each pixel is converted into a color code. The achromatic color includes both white and black, and whether the pixel is white or black depends on the density. The density depends on the brightness (V). Although the brightness of a pixel is determined by the balance of the densities of R, G, and B, it is calculated by weighting as shown in the following formula in accordance with the characteristics of the spectral sensitivity of R, G, and B.

[0044]

[Formula 3] V = aG + bR + cB

In order to calculate the lightness V by this equation, it is necessary to multiply the respective densities of R, G and B by a coefficient and then add them, so that the circuit scale for calculation becomes large.

Therefore, in the present embodiment, since the G spectral sensitivity of the image sensor is close to the human visual acuity and the G spectral sensitivity is wide, the lightness is determined by the G data. That is, in the above equation, a = 1.
0, b = 0, and c = 0. Most of the colors on the actual manuscript contain a large amount of G component, so even if the brightness is determined only by the G data in this way, the human sense does not feel much difference from the actual brightness. . Nevertheless, depending on the color, there is a difference between the lightness determined only by the G data and the actual lightness, so in the present embodiment, the density correction unit 4 in the subsequent stage is
5, the density balance for each color is adjusted.

FIG. 16 shows the hue judging section 41 in this embodiment.
3 is a block diagram showing the configuration of FIG. The hue determination unit 41 shown in this figure is a subtractor 40 that subtracts B data from R data.
1 and a subtractor 402 for subtracting G data from R data
And RB and R obtained by the subtractors 401 and 402
A RAM 403 for inputting both data of -G and outputting a color code is provided. This hue determination unit 41
RG by the RGB misregistration correction unit 22 of FIG.
The R, G, and B data after the B position shift correction is performed are input. Then, subtracters 401 and 402 respectively obtain RB and RG, and R is calculated from these data.
The color code 404 is generated by the AM 403.
Further, the G data input to the hue determination unit 41 is output as it is as the input density data 405.

FIG. 17 is a functional block diagram showing functions of the RAM 403 of FIG. RAM4 as shown in this figure
03 is the R- obtained by the subtracters 401 and 402.
A hue calculation unit 411 that obtains a hue H from both B and R-G data by an equation; and a saturation calculation unit 412 that similarly obtains a saturation C from both R-B and R-G data by an equation.
It has three functions of a color code generation means 413 for generating a color code 404 from H and C obtained by the hue calculation means 411 and the saturation calculation means 412.

As shown in FIG. 14, the ghost canceling section 42 at the next stage of the hue judging section 41 corrects the color code generated by the hue judging section 41. This is because, as a result of the RGB misregistration correction of the video (2) circuit 203, for example, an erroneous hue determination may be made at the edge portion of the black image on the document, and a color code other than the achromatic color may be generated. This is a process for converting a color code into an achromatic color code. This erroneous color code is called a ghost, and the change pattern of the color code when the ghost occurs is known in advance. Therefore, when the pattern matches, the color code is corrected to an achromatic color. Hereinafter, the color code corrected by the ghost cancel unit 42 will be referred to as an input color code.

The input density data and the input color code thus generated are sequentially stored in the buffer memory 43.
Will be stored in. On the other hand, the input color code 47 is A
It is sent to the R circuit 205. In this embodiment, various edits can be performed in real time on a region surrounded by a marker written on a document using a marker pen, and the region surrounded by the marker is detected. The AR circuit 205 does this.

After the AR circuit 205 has been described, the rest of the color circuit 204 will be described.

FIG. 19 is a block diagram of the AR circuit 205. The AR circuit 205 includes a marker flag generation unit 61 that inputs the input color code 47 from the color circuit 204.
And a parallel-serial conversion (hereinafter, referred to as PS conversion) unit 62, a region recognition unit 63, and a serial-parallel conversion (hereinafter, referred to as SP conversion) unit which are sequentially provided in the subsequent stage of the marker flag generation unit 61. 64 and a control unit 65 that controls the above-mentioned units 61 to 64. The control unit 65 is connected to the VME bus 16, inputs the control signal 51 from the color circuit 204, and sends the control signal 49 to the color circuit 204.

The input color code 47 sequentially sent from the color circuit 204 is a signal for each block. First, the marker flag generation unit 61 determines from the input color code whether or not it is a marker image, and when it is a marker image, generates a marker flag. Next, the PS converter 62 converts the marker flag subjected to block processing into a signal of one line. The area recognition unit 63 recognizes the area surrounded by the markers from the thus obtained one-line marker flag.
Here, a region signal indicating the inside of the region is generated. The generated area signal is again divided into each block by the SP conversion unit 64, and is sequentially output as the area signal 48 to the color editing unit 44 of the color circuit 204. The reason why the buffer memory 43 is provided in the color circuit 204 is that it takes time for the AR circuit 204 to recognize the area. Therefore, the input color code and the input density data are stored during this period.
This is to match the timing with the area signal 48 from the R circuit 204.

Here, the description returns to the color circuit 204 in FIG. The block-divided area signal 48 output from the AR circuit 205 is input to the color editing unit 44, and the control signal 49 is input to the control unit 46. The control section 46 reads the input density data and the input color code of the corresponding pixel in synchronization with the area signal 48 from the buffer memory 43 and sends them to the color editing section 44. In the color editing unit 44, the area signal 4
The following processing is performed on the inside or outside of the area designated by 8, or on the entire area. That is, the copying machine of the present embodiment is a two-color copying machine, and it is possible to specify which color on the original is printed by which color of the two colors by the sub color flag.
For example, the input color blue can be output in red, or a closed loop can be drawn by a marker and the image inside this loop can be output in black regardless of the color. Further, the drop color flag can be used to specify which color image on the document should be erased.
With this function, for example, a marker is not necessary and is implicitly deleted. In addition, it is possible to specify whether or not the background removal to be performed in the next stage is performed on the inside and outside of the area by the BKG enable flag. The color editing unit 44 generates these flags. The color editing unit 44 outputs the input color code and the input density data in addition to the sub color flag, the drop color flag, and the BKG enable flag.

The flag, the input density data, and the input color code generated in this manner are sequentially sent to the density correcting section 45. The density correction unit 45 whitens (erases) the density data of pixels for which the drop color flag is set, or for each color on the document (for each input color code).
This is to enable independent density adjustment. As shown in FIG. 18, the density correction unit 45 uses the input color code 451 from the color editing unit 44, the sub color flag 452, and the input density data 453 as address inputs, and the sub color flag 452 and the corrected density data. It has a RAM 450 that functions as a lookup table that outputs the output density data 455. The density correction unit 45 uses the input color code 451.
The output density data 455 corresponding to the input density data 453 is determined by the combination of the input color determined by the sub color flag 452 and the output color determined by the sub color flag 452. The density correction unit 45 performs processing such that when the input color red is output in red, it is output darkly.

In the present embodiment, the density correction section 45 can be used to correct the change in the density balance for each color caused by determining the input density data only by the G data. That is, the correction can be realized by setting the output density data corresponding to the input density data in the RAM 450 for each input color determined by the input color code 451. With this correction, especially in a device that outputs in N colors, a sufficient correction effect is obtained and an output without discomfort is obtained, so that it is not necessary to obtain density data from R, G, B data, and the circuit scale is reduced. Can be reduced. RAM4
The content of 50 is the CP shown in FIG. 7 every time the setting is changed.
It is loaded by the CPU 111 in the U (1) circuit 209.

The output 52 of the sub color flag, the BKG enable flag, the area signal, the output density data, etc. processed in this way is sequentially sent to the DF circuit 206 of FIG.

The DF circuit 206 whitens the background portion of the document where the BKG enable flag is set, and performs edge enhancement and smoothing processing by a digital filter according to the selected image mode. When the background density of the image edge portion is raised by the smoothing processing, correction is performed to make the sub color flag of the raised background pixel the same as the sub color flag of the image portion. The outputs of the sub color flag, the density data, the area flag, the BKG flag, etc. processed in this way are sequentially sent to the HTP circuit 207.

The HTP circuit 207 reduces or enlarges an image,
Density adjustment and halftone processing for converting multi-valued image data into four-valued data having area gradation are performed. Also, this HT
In the EDIT circuit 208 connected to the P circuit 207,
Receiving data from the TP circuit 207, recognizing a rectangular area for various kinds of editing, mirror image editing processing, processing of inverting black and white, and data subjected to dummy editing
Processing for returning to the TP circuit 207 is performed.

The output data of the HTP circuit 207 is sequentially sent to the data processing circuit 210 outside the image processing unit 214 as shown in FIG.

In FIG. 1, the data processing circuit 210 is
The image data sent from the HTP circuit 207 is sent to the page memory circuit 212.
It is stored in the page memory inside. When all the originals have been read in this way, the CPU 11 of the CPU (1) circuit 209
1 is the CPU (2) circuit 2 through the control data line 120
11 sends information to the CPU. Then, the CPU of the CPU (2) circuit 211 informs the control unit 236 of the printing unit 221 through the control data line 237 that the paper is conveyed and that the image data is stored in the page memory.

In FIG. 2, the control unit 236 of the printing unit 221 conveys a predetermined sheet of paper and controls the control signal 238.
Then, the image data 215 in the page memory is read from the data processing circuit 210 at a predetermined timing. The read image data 215 is sent to the data separation unit 231. The data separation unit 231 has a function of distributing the density data by the sub color flag. For example, when the sub color flag is “0”, the density data is sent to the first color image data memory 232 and the second color image data memory 23.
White data is sent to 4. When the sub color flag is "1", the density data is stored in the second color image data memory 2
34, and the white data is sent to the first color image data memory 232. The printing unit 221 prints by using the xerography technique, and the charge corotron, the developing device, and the like have two for the first color and the second color, and the two colors on the photoconductor (drum). The image is transferred onto paper at the same time and fixed. The semiconductor lasers for exposure are provided for each of the first color and the second color, and the driving control of these for each of the first color laser drive section 233 and the second color laser drive section 235. Is.

As described above, according to the present embodiment, the hue judging section 41 determines the density data only by the G data, and the density correcting section 45 corrects the change in the density balance for each color. As described above, it is not necessary to obtain the density data from the R, G, B data, and the circuit scale and the processing time can be reduced.

Further, in the present embodiment, the image sensor 30 in which the respective R, G and B light receiving portions are arranged side by side in the main scanning direction.
In order to prevent erroneous determination of the read color, the RGB misregistration correction unit 22 of FIG. 12 uses the data obtained by calculating the data of a plurality of pixels for the R and B data in the subsequent process. use. If the density is calculated using the corrected data, the density of one pixel is calculated from the data of a plurality of pixels, and the original resolution of the image sensor cannot be obtained. Therefore,
In the present embodiment, the density is determined only by the G data that does not use the calculation result of a plurality of pixels, so that it is possible to prevent erroneous determination of the read color and improve the resolution. Therefore, it is possible to reduce the circuit scale and improve the resolution at the same time.

The present invention is not limited to the above embodiment,
For example, the functions of the RAM 403 of FIG. 16 and the RAM 450 of FIG. 18 may be realized by a ROM or a logic circuit.

The three primary colors are not limited to R, G and B, but may be complementary colors.

[0067]

As described above, according to the inventions of claims 1 to 3, the density information for each pixel is generated by using the data of one color among the data of three primary colors, and the data of the three primary colors is used. Since the color information for each pixel is generated and the density information is corrected for each color based on the color information,
It is possible to reduce the circuit scale and the processing time when the density information is generated from the read data.

According to the invention of claim 4 or 5, read data is obtained by using an image sensor in which the light receiving portions of the three primary colors are arranged side by side in the main scanning direction. When the process of correcting the deviation of the light receiving portion of each color is performed, the density information for each pixel is generated by using the data of one color which is the reference of the reading position in this correction, so that the resolution can be improved. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image scanner unit according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a printing unit according to an embodiment.

FIG. 3 is an explanatory diagram showing a part of a cross section of an image scanner unit according to an embodiment.

FIG. 4 is a perspective view showing a part of the reference plate of FIG.

5 is a plan view of the image sensor of FIG.

6 is an explanatory view showing a pixel array of one chip of the image sensor of FIG.

7 is a block diagram of a CPU (1) circuit of FIG. 1. FIG.

FIG. 8 is a block diagram of the analog circuit of FIG.

9 is a block diagram of the video (1) circuit of FIG. 1. FIG.

FIG. 10 is an explanatory diagram showing an output image data string of the CCD gap correction unit in FIG.

11 is an explanatory diagram showing an output image data string of the RGB separation unit in FIG.

12 is a block diagram of the video (2) circuit of FIG. 1. FIG.

FIG. 13 is an explanatory diagram showing blocks divided by a data block division unit of FIG. 12.

FIG. 14 is a block diagram of the color circuit of FIG.

FIG. 15 is an explanatory diagram showing a polar coordinate system for explaining how to obtain hue and saturation.

16 is a block diagram showing a configuration of a hue determination unit of FIG.

17 is a functional block diagram showing functions of the RAM 403 of FIG.

FIG. 18 is a block diagram showing the density correction unit of FIG.

FIG. 19 is a block diagram of the AR circuit of FIG.

FIG. 20 is an explanatory diagram for explaining correction such that each reading position of R, G, and B becomes the same virtual point.

[Explanation of symbols]

41 ... Hue judgment section, 45 ... Density correction section, 220 ... Image scanner section, 308 ... Image sensor

Claims (5)

[Claims] 1. A reading means for reading an original to obtain three primary color data for each pixel, and one of the three primary color data obtained by the reading means.
Density information generating means for generating density information for each pixel using color data; color information generating means for generating color information for each pixel using the three primary color data obtained by the reading means; The concentration information generated by the generation means,
An image reading apparatus comprising: a density correction unit that corrects each color based on the color information generated by the color information generation unit. 2. The image reading apparatus according to claim 1, wherein the reading unit has an image sensor in which light receiving portions for each of the three primary colors are arranged side by side in the main scanning direction. 3. The reading means uses red as three primary color data,
3. The image reading apparatus according to claim 1, wherein data for three primary colors of green and blue are obtained, and the density correction means is for generating density information by using green data. 4. A reading means for reading a document by using an image sensor in which light receiving portions for each of the three primary colors are arranged side by side in the main scanning direction to obtain three primary color data for each pixel, and one of the three primary colors. In order to virtually match the reading positions of the other two colors with the reference reading position of the color as the reference, the data for each pixel of the other two colors is converted into the data of a plurality of pixels for that color. A position deviation correcting unit that corrects the position by a calculation using, and a reference of a reading position in the position deviation correcting unit 1
Density information generation means for generating density information for each pixel using color data, and color information generation means for generating color information for each pixel using the three primary color data corrected by the positional deviation correction means , The density information generated by the density information generating means,
An image reading apparatus comprising: a density correction unit that corrects each color based on the color information generated by the color information generation unit. 5. The reading means uses red as three primary color data,
Data for the three primary colors of green and blue are obtained, the positional deviation correction means corrects data for the other two colors with the green reading position as a reference, and the density correction means uses green data. The image reading apparatus according to claim 4, wherein the image reading apparatus is configured to generate density information by using the image reading apparatus.