JP3185376B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus 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 apparatus for reading a color image using, for example, a color image sensor is used as an input means. In an image reading apparatus that handles a color image in this way, three such as red (hereinafter, referred to as R), green (hereinafter, referred to as G), and blue (hereinafter, referred to as B) obtained by the image sensor. The primary color data is HCV,
Data processing such as generation of color information and density information by performing conversion into color system data such as XYZ and L ^* a ^* b ^* is performed.

[0003]

However, the operation for conversion to the color system as described above requires multiplication and exponentiation, which increases the circuit scale for performing the operation and increases the operation time. There is a problem that it becomes.

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, since the actual document reading position is shifted depending on each color of B, G, and R, an erroneous determination occurs when the color of the image 502 is determined. Then, R,
Correction is required so that the G and B reading positions are at the same virtual point 503. As an example of this correction, R and B data are obtained by calculating data of R and G pixels on the left and right of G with reference to the position of G. This correction will be described with reference to FIG.
4 of R, G, the original data each R _n of B, G _n, B
and _n, R _n the data after correction, respectively ', G _n', B
_{When n} ′, G _n ′ uses G _n as it is,
R _n 'is determined by the operation of R _{n - 1} and R _n, and B _n ' is determined by the operation of B _n and B _{n + 1} .

However, when the density of each pixel is obtained using the corrected data obtained by the above calculation, the density of one pixel is determined based on the data of a plurality of pixels. There is a problem that the deterioration of the film occurs.

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

Another object of the present invention is to obtain read data 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 obtain light receiving portions of each color for the read data. An object of the present invention is to provide an image reading apparatus capable of improving the resolution when performing a process of correcting the deviation of the image.

[0008]

According to the first 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 three-color data obtained by the reading means.
Density information generating means for generating density information for each pixel using data of one of the primary color data, and color information generating means
Adjust the output density balance for each color information generated by
And a density correcting means for correcting the density information generated by the density information generating means so as to adjust the density information.

In this image reading apparatus, reading means obtains three primary color data for each pixel, and density information generating means generates density information for each pixel using data of one of the three primary color data. 3 by information generation means
Color information for each pixel is generated using the primary color data. Also, output for each color information generated by the color information generating means
The density information generating means adjusts the density balance.
Thus, the generated density information is corrected.

According to a second aspect of the present invention, in the image reading apparatus of the first aspect, the reading unit uses an image sensor in which light receiving units for each of the three primary colors are arranged in the main scanning direction. The original is read.

According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the reading means obtains data of three primary colors of red, green, and blue as three primary color data. The means generates density information using green data.

According to a fourth aspect of the present invention, there is provided an image reading apparatus comprising:
A reading unit that reads 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 obtains three primary color data for each pixel, and sets a reading position of one of the three primary colors as a reference. In order to virtually match the reading position of the other two colors with the reference reading position, the data for each pixel of the other two colors is corrected by an operation using data of a plurality of pixels for that color. Displacement correction means for performing the correction, density information generation means for generating density information for each pixel using data of one color serving as a reference of a reading position in the displacement correction means, a color information generating means for generating color information for each pixel using the three primary data, lust generated by the color information generating means
Density correction means for correcting the density information generated by the density information generation means so as to adjust the balance of the output density for each report .

In this image reading apparatus, the reading means reads the original 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. By means of deviation correction,
With the reading position of one of the three primary colors as a reference, the data of the other two colors are corrected in order to virtually match the reading position of the other two colors with the reference reading position. Then, density information for each pixel is generated by the density information generating means using one color data serving as a reference for the reading position, and color information for each pixel is generated by the color information generating means using the corrected three primary color data. Generated. Also generated by the color information generation means
To adjust the output density balance for each color information
The density information generated by the density information generating means
I did it.

According to a fifth aspect of the present invention, in the image reading apparatus according to the fourth aspect, the reading means obtains data of three primary colors of red, green and blue as the three primary color data. Is for correcting data of the other two colors with reference to the green reading position, and the density correcting means generates density information using the green data.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 19 relate to one 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 processing and
It comprises an image scanner unit equipped with a page memory for storing image data subjected to image editing, and a print unit for printing the image data stored in 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, various image processing / editing functions, and the like, so that a desired copy can be obtained by specifying the control panel. I have.

FIG. 1 is a block diagram showing the configuration of the image scanner unit. The image scanner unit 220 has an image sensor 308 using a charge-coupled device (hereinafter, referred to as a CCD). The image sensor 308 is mounted on the CCD drive circuit 200. In the subsequent stage of the CCD drive circuit 200, an analog circuit 201,
Video (1) circuit 202, video (2) circuit 203, color circuit 204, digital filter circuit (hereinafter, DF)
Described as a circuit. ) 206 and a halftone processing circuit (hereinafter H
It is described as a TP circuit. ) 207 are provided. Further, 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. The video (1) circuit 202 to the HTP circuit 20
7. AR circuit 205 and EDIT circuit 208 and a central processing unit (hereinafter, referred to as CPU) for controlling these circuits
(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 referred to as an image processing unit 214.

A data processing circuit 210 is connected to the subsequent 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. The CPU (2) circuit 211
Is connected to a control panel 213. The data processing circuit 210 outputs the image data 215 to the printing unit and receives a control signal 238 from the printing unit. The CPU (2) circuit 211
Is a CPU (1) circuit 209 via a control data line 120
And a control unit of the printing unit via a control data line 237.

FIG. 2 is a block diagram showing the configuration of the printing unit. The print unit 221 is provided with the image scanner unit 22.
Data separation unit 23 for inputting image data 215 from 0
1 and a first set provided after the data separation unit 231.
A color image data memory 232 and a second color image data memory 234, a first color laser driver 233 provided after the first color image data memory 232, and a second color image data memory 234 A second-color laser driving unit 235 and a control unit 236 for controlling the above units are provided. The control unit 236 is connected to the CPU (2) circuit 211 of the image scanner unit 220 via a 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 a cross section of the image scanner section. The image scanner unit includes a plurality of document feed rollers 302 provided above the document conveying path,
303, a plurality of rollers 304 and 305 provided below the document feed path and nipping the document 310 together with the document feed rollers 302 and 303. Further, a platen glass (not shown) is provided below the middle of the document conveying path, and a platen roller 311 is provided on the platen glass. A light source 306, an image sensor 308 mounted on the CCD drive circuit 200, and a convergent rod lens that forms an image of the original 310 illuminated by the light source 306 on the image sensor 308 below the platen glass. An array 309 is provided. Further, a sensor 301 for detecting the document 310 is provided in the document insertion section. The platen roller 311
Has a plurality of planes around the platen roller 311.
A reference plate 312 rotatable about the central axis is provided. As shown in FIG. 4, the reference plate 312 has a black surface 313 serving as a reference for a black level, and a white surface 314 serving as a reference for a white level. 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 this embodiment is a full-color contact sensor, and as shown in FIG. 5, five line-type sensor chips (1) to staggeredly arranged.
(5) It has 321-325. Sensor chips (1), (3), (5) and sensor chips (2), (4)
Is spatially shifted by Δx. For this reason, the image data read by the image sensor 308 includes two chip groups (sensor chips (1), (3), (5) and sensor chips (2), (4)) of different portions on the document. Data will be read simultaneously. A process of converting this data into data obtained by reading the same line of the document is performed in a 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 document, and these three image sensors 308 are attached so as to read the same line of the document.

FIG. 6 is an explanatory diagram showing the pixel arrangement of one chip of the image sensor 308. Image sensor 30
Reference numeral 8 denotes a configuration in which pixels for each color having B, G, and R color filters as three primary colors are arranged in the order of B, G, and R.

Next, among the circuits of the image scanner section 220, the configuration and operation of a portion particularly relating to the present embodiment will be described.

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

In FIG. 1, when the user designates a desired number of copies and various image processing / editing from the control panel 213, the CPU on the CPU (2) circuit 211 transmits the control data line 120 to the CPU (1) circuit 209. The CPU 111 sends various image processing / editing information selected by the control panel 213 to the CPU 111. 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 print unit 221 through the control data line 237.

In FIG. 7, various kinds of image processing / editing information sent through the control data line 120 are taken into the CPU (1) circuit 209 via the serial communication section 118 and decoded by the CPU 111. CPU111
Indicates various parameters (control data) corresponding to the image processing / editing information in the VME bus I / F 115 and the VME bus 16.
Are set in predetermined registers and RAMs of the circuits 202 to 208 in the image processing unit 214.

Next, in FIG. 3, when the original 310 is inserted into the image scanner unit 220, the sensor 301 is turned on, and this is detected by the CPU 111 through the input control unit 117 of the CPU (1) circuit 209 in FIG. The original feed motor is driven, and the original 310 is conveyed by the original feed rollers 302 and 303. When the conveyed document 310 reaches the platen roller 311, the light source 306
The light 307 radiated by the document 310 and reflected by the original 310 is incident on the image sensor 308, and is driven by the CCD drive circuit 200 as shown in FIG.
08, the original image is read, and the CCD video signal 9 is read.
Are sequentially processed by the analog circuit 201.

FIG. 8 is a block diagram of the analog circuit 201. The analog circuit 201 includes the CCD drive circuit 20
A sample hold unit 1 for extracting a valid image signal from the CCD video signal 9 from 0, a gain control unit 2, a dark correction unit 3, an offset control unit 4, and an analog The digital conversion (hereinafter, referred to as A / D conversion) section 5 and the digital-analog conversion (hereinafter, referred to as D / A conversion) data from the video (1) circuit 202 are D / A.
A D / A converter 6 for converting and setting the gain control unit 2 and the offset control unit 4;

Prior to reading the original, when the image scanner unit 220 is turned on, the black surface 313 of the reference plate 312 shown in FIG. 4 is put out on the platen glass and read, and the read value at this time becomes a predetermined value. The offset value of the offset control unit 4 is
1 is automatically set for the D / A converter 6 (hereinafter, this is referred to as automatic offset control: AOC). Next, the reference plate 3 shown in FIG.
12 and read it out, and read the gain value of the gain control section 2 from the CPU 111 to the D / A conversion section 6 so that the read value at this time becomes a predetermined value.
Is automatically set (hereinafter referred to as automatic gain control: AGC). Since such adjustments have been made in advance, the actual original read data becomes video data having a sufficient dynamic range without saturation, and is digitized by the A / D converter 5 to be converted into image data 8. The 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 the 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 provided in the subsequent stage of the CCD gap correction unit 11, and control for controlling the above units 11 to 13. A unit 14 and a clock generation unit 15 that supplies a clock to each of the units 11 to 13 are provided. The control unit 14
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 at 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 shifted by Δx. Therefore, the CCD gap correction unit 11 performs a process of converting data read by the two chip groups into data obtained by reading the same line of the document. Specifically, the CCD gap correction unit 11 delays the data read by the chips (2) and (4) 322 and 324 using a memory to convert the data into the same line read data. The output pixel data sequence of the CCD gap correction unit 11 is a sequence of B, G, and R data serially arranged as shown in FIG. 10, which is shown in FIG.
As shown in (c), the RGB separation unit 12 performs a process of converting the pixel data into R, G, and B pixel data strings. The pixel data thus separated into R, G, and B are sequentially sent to the dark shading correction unit 13, where dark shading correction is performed. The dark shading correction is performed by performing AOC and AGC operations when the power of the image scanner unit 220 is turned on before reading the original, and then performing the black surface 313 operation.
In this process, the image data obtained by reading the image data is stored in a memory for each pixel, and the black surface read data stored for each pixel is subtracted 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 outputs the video (1)
A bright shading corrector 21 for inputting the image data 18 from the circuit 202;
RGB position shift correction unit 22, sensor position shift correction unit 24 and data block division unit 2 provided in the subsequent stage in order.
5, a control unit 26 for controlling the units 21 to 25, and a clock generation unit 27 for supplying a clock to the units 21 to 25. The control unit 26 is connected to the VME bus 16, receives a control signal 19 from the video (1) circuit 202, and sends a control signal 30 to the color circuit 204. Further, the clock generation unit 27 sends a control clock 28 to each subsequent circuit.

The image data 18 sent to the video (2) circuit 203 is first subjected to bright shading correction by a bright shading correction section 21. In the light shading correction, the image data obtained by reading the white surface 314 is stored in a memory for each pixel after the AOC and AGC operations, similarly to the dark shading correction, and the image data of each pixel when the document is actually read is stored. Is a process of normalizing (dividing) with the white surface read data for each pixel that has stored.
The image data that has been subjected to the light shading correction and the dark shading correction is image data free from the influence of the light amount distribution of the light source 306 and the influence of the sensitivity variation for 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 bright shading correction unit 21 and the dark shading correction unit 13 can be read and written from the CPU 111 via the VME bus 16, so that the AOC , AGC and light / dark shading correction control by the CPU 11
One can do it.

The image used in this embodiment is
The sensor 308 includes B, G, and R pixels (receivers) as shown in FIG.
Light portions) are arranged side by side in the main scanning direction, and each of B, G, and R
One pixel in read data by combination of one pixel
Is composed. Therefore, the image sensor 308
If the original is scanned by B, G, R
The actual reading position is shifted. As a result, the image
Color is determined by the next stage color circuit 204
Misjudgment in the case of
Will be reproduced. So, read B, G, R
Correction is required so that the positions are at the same virtual point. this
The correction is performed by the RGB position shift correction unit 22. Real truth
In the embodiment, the RGB position shift correction is performed for the G image with high sensitivity.
Using the elementary position as a virtual point as a reference position,
The value at the virtual point is calculated. For example, in FIG.
The data of each pixel of B1 to B3, G1 to G3, and R1 to R3 shown in FIG.
Data to B₁~ B_Three, G₁~ G_Three, R₁~ R_ThreeWhen
B1 to B3, G1 to G3,
The data of each pixel of R1 to R3 is B₁'~
B _Three', G₁'~ G_Three', R₁'~ R_Three'Then G
_Two', B_Two', R_Two′ Is calculated by
It is required.

[0035]

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

This correction is performed for all the pixels, and the data after the correction is used for the hue determination at the subsequent stage.

The operation up to this point has been described with respect to the image sensor 3.
08 is one, but as described above, actually, three image sensors 308 are used to read a wide document. These three image sensors 308 are adjusted and mounted so that the same line of the document can be read, but actually, they are shifted. The sensor position shift correction unit 24 corrects this shift. The sensor position shift correction is performed in substantially the same way as the CCD gap correction, by delaying the image data of each sensor by an arbitrary time using a memory, so that the image data of the three sensors can be scanned in the main scanning direction on the original at the joint. It is intended to be an adjacent image in the direction.

In the case of a high-speed and wide digital copying machine, it is necessary to process image data at high speed.
And digital integrated circuits have limitations in high-speed operation. Therefore, the output image data of the sensor position shift correcting unit 24 is
The data block dividing unit 25 divides the data 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 document 310 is divided into a total of six blocks as shown in FIG. Processing will be performed. The image data 29 divided into blocks in this manner 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 judging unit 41 for inputting the image data 29 from the video (2) circuit 203, and a ghost canceling unit 42, a buffer memory 43, and a color editing unit 44, which are sequentially provided after the hue judging unit 41. And a density correction section 45, and a control section 46 for controlling the above sections 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 is an R, G, B color image signal. The color code signal obtained by judging the color of the image on the original by the hue judging section 41 and inputting the same. And density data.

Here, the hue judging section 41 will be described in detail. Conventionally, when a color code and a density are determined from R, G, and B data, for example, the hue (H), saturation (C), and lightness (V) are obtained by calculating the R, G, and B data. The color code is determined by the combination of the color and the saturation, and the density is determined by the brightness. In the calculation for calculating the hue and saturation, the RB axis and the R-axis as shown in FIG.
Use the polar coordinates represented by the G axis. Saturation (C) is the center R of coordinates (RB, RG) in the 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 magnitude of H determines the color of the image. Specifically, the saturation (C) and the hue (H) are obtained by the following equations. Note that R, G, and B in the following formulas are density data for each color.

[0042]

C = {(RB) ² + (RG) ² } H = tan ^-1 {(RG) / (RB)}

A color having low saturation is white or black, that is, an achromatic color. The range of achromatic color differs depending on the color.
That is, 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 is determined by the density. The density is determined by the lightness (V). Although the brightness of a pixel is determined by the balance of the density of R, G, and B, it is calculated by weighting as shown in the following formula according to the spectral sensitivity characteristics of R, G, and B.

[0044]

## EQU3 ## V = aG + bR + cB

In order to calculate the lightness V by this equation, addition must be performed after multiplying each density of R, G, and B by a coefficient, so that the circuit scale for the calculation becomes large.

Therefore, in this embodiment, since the spectral sensitivity of G of the image sensor is close to the relative luminous efficiency of humans and the spectral sensitivity of G is wide, the brightness 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 an actual document include a considerable amount of the G component. Therefore, even if the brightness is determined only by the G data in this way, the difference between the actual brightness and the actual brightness is not felt by a human sense. . Even so, there is a difference between the brightness determined by only the G data and the actual brightness depending on the color.
In 5, the density balance of each color is adjusted.

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

FIG. 17 is a functional block diagram showing functions of the RAM 403 in FIG. As shown in FIG.
03 is the value of R− obtained by the subtractors 401 and 402.
Hue calculating means 411 for calculating hue H from both data of B and R-G by an equation; and saturation calculating means 412 for calculating chroma C from both data of R-B and R-G by an equation;
The color code generator 413 has three functions of generating a color code 404 from H and C obtained by the hue calculator 411 and the saturation calculator 412.

As shown in FIG. 14, a 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 position shift correction of the video (2) circuit 203, for example, an erroneous hue is determined at an edge portion of a black image on a document, and a color code other than an achromatic color may be generated. This is a process of converting a color code into an achromatic color code. This erroneous color code is called a ghost, and since the change pattern of the color code when the ghost occurs is known in advance, the color code is corrected to an achromatic color when the pattern matches. Hereinafter, the color code corrected by the ghost cancel unit 42 is 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.
It is stored in. On the other hand, the input color code 47 is A
The signal is sent to the R circuit 205. In the present embodiment, various edits can be performed in real time on an area surrounded by a marker written on a document using a marker pen, and the area surrounded by the marker is detected. The AR circuit 205 performs this operation.

Here, after explaining the AR circuit 205, the remaining part of the color circuit 204 will be explained.

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, an area recognition unit 63, and a serial-to-parallel conversion (hereinafter, referred to as SP conversion) unit, which are sequentially provided after the marker flag generation unit 61. 64, and a control unit 65 for controlling the above-described units 61 to 64. The control unit 65 is connected to the VME bus 16, receives a control signal 51 from the color circuit 204, and sends a 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 whether or not the image is a marker image from the input color code, and generates a marker flag if the image is a marker image. Next, the PS conversion unit 62 converts the block-processed marker flag into a one-line signal. The area recognition unit 63 recognizes the area surrounded by the marker from the one-line marker flag thus obtained,
Here, an area signal indicating the inside of the area is generated. The generated area signal is again divided for each block by the SP conversion section 64, and is sequentially output to the color editing section 44 of the color circuit 204 as the area signal 48. The reason that the buffer circuit 43 is provided in the color circuit 204 is that it takes time for the AR circuit 204 to recognize the area. During this time, the input color code and the input density data are stored and stored.
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 shown 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 unit 46 reads the input density data and the input color code of the corresponding pixel from the buffer memory 43 in synchronization with the area signal 48 and sends them to the color editing unit 44. In the color editing unit 44, the area signal 4
The following processing is performed on the inside or outside of the area specified 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 document is to be printed in which of the two colors by the sub-color flag.
For example, it is possible to output blue as an input color in red, draw a closed loop with a marker, and output black in any image inside the loop in any color. Further, it is possible to specify which color image on the document is to be erased by the drop color flag.
With this feature, for example, markers are implicitly erased because they are unnecessary. In addition, it is possible to specify whether or not the background removal performed in the next stage is performed inside and outside the region by using the BKG enable flag. The color editing unit 44 generates these flags. The color editing unit 44 outputs an input color code and input density data in addition to the above-described sub color flag, drop color flag, and BKG enable flag.

The flag, the input density data and the input color code generated in this way are sequentially sent to the density correction section 45. The density correction unit 45 changes the density data of the pixel on which the drop color flag is set to white (turns it off), 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 receives the input color code 451, the sub color flag 452, and the input density data 453 from the color editing unit 44 as address inputs, and outputs the sub color flag 452 and the corrected density data. And a RAM 450 functioning as a look-up table for outputting the output density data 455. The density correction unit 45 is provided with an input color code 451
The output density data 455 for the input density data 453 is determined by the combination of the input color determined by the input color and the output color determined by the sub color flag 452. The density correction unit 45 performs processing such as outputting dark red when the input color red is output in red.

In this embodiment, the density correction unit 45 can be used to correct a change in the density balance for each color caused by determining the input density data based on only the G data. That is, the above correction can be realized by setting the output density data for 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 can be obtained, and an output without a sense of incongruity can be obtained. Therefore, it is not necessary to obtain density data from R, G, and B data. Can be reduced. In addition, RAM4
Each time the setting is changed, the contents of 50 shown in FIG.
It is loaded by the CPU 111 in the U (1) circuit 209.

The outputs 52 such as the sub-color flag, the BKG enable flag, the area signal, and the output density data processed in this manner are sequentially sent to the DF circuit 206 in FIG.

The DF circuit 206 performs processing such as whitening the background of the document in the portion where the BKG enable flag is set, and processing such as edge enhancement and smoothing by a digital filter according to the selected image mode. When the background density at the edge of the image is raised by the smoothing process, the sub-color flag of the raised background pixel is corrected to be 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, and the like thus processed are sequentially sent to the HTP circuit 207.

The HTP circuit 207 reduces or enlarges an image,
It performs density adjustment and halftone processing for converting multi-valued image data into quaternary data with area gradation. Also, this HT
In the EDIT circuit 208 connected to the P circuit 207, H
Receiving the data from the TP circuit 207, it recognizes a rectangular area for performing various kinds of editing, performs mirror image editing processing, inverts white and black, and performs data that has been subjected to apparent editing.
A process to return 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 section 214 as shown in FIG.

In FIG. 1, the data processing circuit 210
The image data sent from the HTP circuit 207 is sent to the page memory circuit 212, and the page memory circuit 212
In the page memory inside the After reading all the originals in this manner, the CPU 11 of the CPU (1) circuit 209
1 is a CPU (2) circuit 2 through a control data line 120
11 sends information to the CPU. Then, the CPU of the CPU (2) circuit 211 notifies the control unit 236 of the print unit 221 via the control data line 237 that the paper is conveyed and that the image data is stored in the page memory.

In FIG. 2, a control unit 236 of the print unit 221 conveys a predetermined sheet and controls a control signal 238.
Thus, 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 sorting the density data according to 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
4 is sent white data. 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 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 are used for two colors on the photoconductor (drum). The image is simultaneously transferred to paper and fixed. The semiconductor laser for exposure is provided for each of the first color and the second color, and the drive of these is controlled based on the image data. The first color laser drive unit 233 and the second color laser drive unit 235 It is.

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

In this embodiment, the image sensor 30 in which the R, G, and B light receiving units are arranged in the main scanning direction is arranged.
In order to prevent erroneous determination of the read color, the RGB position shift 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 processing. use. If the density is obtained by using the data after the correction, the density of one pixel is obtained by the data of a plurality of pixels, so that 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 erroneous determination of the read color can be prevented and the resolution can be improved. Therefore, it is possible to achieve both a reduction in circuit scale and an improvement in resolution.

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

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

[0067]

As described above, according to the first to third aspects of the present invention, density information for each pixel is generated by using data of one of the three primary color data, and the three primary color data is generated. and generates color information of each pixel using, lust
Of the output density for each color information generated by the
Generated by density information generation means to adjust lance
Since the corrected density information is corrected, it is possible to reduce the circuit scale and the processing time when generating the density information from the read data.

According to the fourth or fifth aspect of the present invention, read data is obtained using an image sensor in which light receiving sections of the three primary colors are arranged side by side in the main scanning direction. On the other hand, when performing a process of correcting the displacement of the light receiving unit of each color, density information for each pixel is generated using data of one color serving as a reference of a reading position in the correction, and the density information is generated by color information generation. Raw by means
Adjust the output density balance for each generated color information.
As a result, the resolution can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating 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 the image scanner unit in one embodiment.

FIG. 4 is a perspective view showing a part of the reference plate of FIG. 3;

FIG. 5 is a plan view of the image sensor of FIG. 3;

FIG. 6 is an explanatory diagram showing a pixel array of one chip of the image sensor of FIG. 5;

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

FIG. 8 is a block diagram of the analog circuit of FIG. 1;

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

FIG. 10 is an explanatory diagram showing an output image data string of the CCD gap correction unit in FIG. 9;

11 is an explanatory diagram showing an output image data string of the RGB separation unit in FIG. 9;

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

FIG. 13 is an explanatory diagram showing blocks divided by a data block dividing unit in FIG. 12;

FIG. 14 is a block diagram of the color circuit of FIG. 1;

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

FIG. 16 is a block diagram illustrating a configuration of a hue determination unit in FIG. 14;

17 is a functional block diagram illustrating functions of a RAM 403 in FIG.

FIG. 18 is a block diagram illustrating a density correction unit of FIG. 14;

FIG. 19 is a block diagram of the AR circuit of FIG. 1;

FIG. 20 is an explanatory diagram for explaining correction such that the R, G, and B reading positions become the same virtual point.

[Explanation of symbols]

41: Hue determination unit, 45: Density correction unit, 220: Image scanner unit, 308: Image sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-249357 (JP, A) JP-A-61-154357 (JP, A) JP-A-59-211377 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04N 1/60 H04N 1/04 H04N 1/46

Claims (5)

(57) [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.
A density information generating means for generating density information of each pixel by using the color data, the color information generating means for generating color information for each pixel using the three primary data obtained by the reading means, the color information Output for each color information generated by the generation means
An image reading apparatus comprising: a density correction unit configured to correct the density information generated by the density information generation unit so as to adjust a density balance . 2. The image reading apparatus according to claim 1, wherein said reading means has an image sensor in which light receiving sections for each of three primary colors are arranged in the main scanning direction. 3. The reading means according to claim 1, wherein said three primary color data are red,
3. An image reading apparatus according to claim 1, wherein data of three primary colors of green and blue are obtained, and said density correction means generates density information using green data. 4. A reading means for reading an original using an image sensor in which light receiving units 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 position of the other two colors with the reading position of the color based on the reading position of the color, the data of each pixel of the other two colors is converted into the data of a plurality of pixels for that color. and positional deviation correcting means for correcting the calculation using, before the reference reading position in the positional deviation correcting means
Serial product color information to generate the color information of each pixel by using the density information generating means for generating density information of each pixel using one color data, the three primary colors data corrected by said positional deviation correcting means Means and output for each color information generated by the color information generating means
An image reading apparatus comprising: a density correction unit configured to correct the density information generated by the density information generation unit so as to adjust a density balance . 5. The reading means according to claim 3, wherein said three primary color data are red,
The data of three primary colors of green and blue are obtained. The misregistration correction means corrects the data of the other two colors with reference to the reading position of green, and the density correction means uses green data. 5. The image reading apparatus according to claim 4, wherein the density information is generated by using the image reading apparatus.