JP2002112033A - Method and device for reading image and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively perform ground color removal at a high speed and, in addition, to excellently reproduce an Ozalid drawing. SOLUTION: In a method for reading image, a scanner 00) reads an image, converts the image into image data, and stores the data in a memory MEM after correction. Reduced image data are extracted or generated from the stored image data and ground-color level data are generated based on the extracted image data. Image data read out from the memory MEM are converted into image data from which the ground color level shown by the data obtained by expanding the ground-color level data correspondingly to the unmagnified image of the image is removed (Figs. 3 and 9) and the converted image data are printed out by means of a printer 400. Alternatively, the reduced image data are generated before the corrected image data are written in the memory MEM and stored in the memory MEM (Figs. 12 and 13). More alternatively, the reduced image data are generated before the corrected image data are written in the memory MEM and the y-direction ground color of the data is calculated and stored in the memory MEM together with the reduced image data. At the time of reading out the image data from the memory MEM, the x-direction ground color of the data is calculated from the y-direction ground color (Figs. 14 and 15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading processing method for processing image data obtained by reading an image by an image reading means so as to clearly express the image, an image reading apparatus and an image forming apparatus using the same. In particular, although not intended to be limited to this, image data of a low-contrast character document, such as a blue-printed document, in which the background density varies greatly,
The present invention relates to a digital copying machine suitable for processing image data that clearly reproduces a character image.

[0002]

2. Description of the Related Art In recent years, digitization of documents has been advanced, and there has been an increasing demand for reading and digitizing paper documents with a scanner or the like. Especially in the design and architectural fields, there is a demand for digitizing and storing blueprints. In a blueprint, a density is present in a background portion which is originally unnecessary information, and the background may not be completely removed by a normal scanner or copy. In some cases, a blueprint is cut and pasted on a white sheet of paper. In this case, only the blueprint is darkened, and the readability of an image in a copy area corresponding to the blueprint is extremely reduced.

Japanese Patent Application Laid-Open No. 6-31359 discloses a method in which a low density peak is detected on each line of an image scan, and a value obtained by adding an offset value to an average value of the low density peaks of each line is set as a threshold. Background Art A background removal apparatus that removes an image density as a background is disclosed.

[0004] Japanese Patent Application Laid-Open No. Hei 9-186872 discloses a background removing apparatus which detects a white peak value in a certain area and sets it as a basic background level.

[0005]

However, Japanese Patent Application Laid-Open No.
The background removing device described in Japanese Patent No. -311359 removes the same background data for each line of image scanning.
It cannot cope with the case where the background density varies on one line.
In the device disclosed in Japanese Patent Application Laid-Open No. 9-186872, a white peak value in a certain area is used as a basic background level, and the background density cannot be calculated or removed following a fluctuating background.

Further, it is sufficient if the background removal processing can be performed with high accuracy by an image processing circuit for correcting the deterioration of the read image due to the reading characteristics of the scanner. However, in practice, it does not work well for the following reasons: The image processing circuit has only a limited memory area of about several tens of lines in the sub-scanning direction, but the arithmetic processing is fast; The memory device has a large memory space capable of storing all the read image data, but a general-purpose processor capable of operating the memory contents is slow, so that only limited processing can be performed in real time. That is, if the background processing is to be sufficiently performed by the image processing circuit,
The image processing speed, that is, the image reading speed must be reduced.

If the general-purpose processor performs background removal when writing or reading data to or from a memory device, the speed of writing or reading data to or from the memory device is reduced. It's hard to make.

It is a first object of the present invention to effectively realize the background removal, and to achieve the above-mentioned effect without significantly lowering the image data processing speed or transfer speed.
The purpose of. In particular, even when the background density changes drastically, such as when a blueprint is cut off on a white paper,
Obtaining image data capable of reproducing drawing data satisfactorily without a decrease in throughput due to prescan, etc.
The purpose of.

[0009]

[Means for Solving the Problems] (1) Image reading means (2
In step (00), the image is read and converted into image data, the image data is corrected and stored in a memory unit (MEM), and reduced image data is extracted or generated from the stored image data, and the ground level data is generated based on the reduced image data. An image reading processing method for converting image data generated and read out from a memory means (MEM) into image data in which the background level represented by data obtained by expanding the background level data so as to correspond to an equal-magnification image is removed (FIGS. 3 and 9). ).

[0010] In order to facilitate understanding, symbols of corresponding elements or corresponding items in the embodiments shown in the drawings and described later are added for reference in parentheses. The same applies to the following.

According to this, the image data obtained and corrected by the image reading means (200) is stored in the memory means (ME
M), the reduced image data is extracted or generated, and the background level is calculated for the reduced image data. Therefore, the spread of the same-size image data on the image plane (the number of image data: the number of pixels) On the other hand, the background level calculation amount is small, that is, since the background level calculation time for one line is short in proportion to the reduction ratio, the background calculation can be performed at relatively high speed and with high accuracy.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (2) An image is read by an image reading means (200) and converted into image data, the image data is corrected and stored in a memory means (MEM), and a reduced image is formed from the corrected image data. Data is extracted or generated and stored in a memory means (MEM), and the image data and the reduced image data are read out from the memory means (MEM) to generate background level data based on the reduced image data, and the memory means (MEM) Converting the image data read from the image data into image data from which the background level represented by data obtained by expanding the background level data corresponding to the same-size image has been removed (FIG. 1)
2 & FIG. 13).

According to this, for example, the image reading means (20
Image processing device (IPP) that corrects image data read in (0)
Thus, reduced image data can be obtained at high speed, and the speed of accumulating image data in the memory means (MEM) does not need to be particularly slowed down. Since the background level is calculated based on the reduced image data, the background level calculation time for one line is short in proportion to the reduction ratio, so that the background calculation can be performed relatively quickly and with high accuracy.

(3) The image is read by the image reading means (200) and converted into image data, the image data is corrected and stored in the memory means (MEM), and the corrected image data is reduced in the main scanning direction. Weighted addition of at least the reduced image data of interest and the smoothing level defined by the reduced image data preceding the reduced image data of interest in the sub-scanning direction (IIR filter processing: equation ) To obtain the smoothing level (y background) in the sub-scanning direction directed to the reduced image data of interest,
And reads out the image data and the smoothing level (y background) from the memory means (MEM), and smoothes it in the main scanning direction based on the smoothing level (y background) (x background). ), And converts the image data read from the memory means (200) into image data from which the background level represented by data obtained by expanding the background level data (x background) for an equal-size image is removed. Processing method (Fig. 1
4 & FIG. 15).

According to this, the IIR filter processing (formula) for smoothing in the sub-scanning direction (y), which is the background tracking processing in the sub-scanning direction (y), which is a part of the background detection processing, is performed by scanner correction. Since the processing is performed by the IPP unit, the background detection accuracy can be further improved and the speed can be increased.

(4) Extraction or generation of reduced image data
Smoothing of image data in main scanning direction (x) and main scanning direction
(x) includes extraction of smoothed image data, which is discrete.

According to this, the average density is stored in the reduced image data, and the extraction can select the extraction image data based on the pixel count or the frequency division of the pixel synchronization pulse, and it is not necessary to perform a fine extraction position calculation. , The processing speed is relatively fast.

(5) Image reading means (200) for reading an image and converting it into digitized image data; Image processing means (IPP) for correcting the image data; Memory device (MEM) for storing data; Reduction processing means (6 / IPP) for extracting reduced image data reduced in the main scanning direction from the image data corrected by the image processing means (IPP);
Means (6) for once writing the image data corrected by P) to the memory device (MEM) and generating background level data from the reduced image data when reading the image data; and An image reading device for converting image data read from the MEM) into image data in which the background level represented by data obtained by expanding the background level data so as to correspond to an equal-size image is removed.

According to this, the image data obtained and corrected by the image reading means (200) is stored in the memory means (ME
M), the reduced image data is extracted or generated, and the background level calculation is performed on the reduced image data. Therefore, the background level calculation time of one line is short in proportion to the reduction ratio. High-speed, highly accurate background calculation can be performed. For example, an original containing a mixture of high-density and low-density backgrounds, such as a blue-printed original, is read, and characters, line drawings, etc.
Image data that clearly shows the value image can be obtained.

(6) The image reading device according to the above (5);
And a printer (400) for forming an image represented by the image data output by the image data processing device on paper.

According to this, it is possible to obtain a copy that clearly shows a binary image such as a character or a line image on an original such as a blue-printed original or the like in which a high density and a low density background are mixed.

(7) A device (200) for reading a document surface and converting it to a digitally converted image signal, a device (IPP) for correcting read scanner data, a memory device (MEM) for storing data, and a memory From a general-purpose processor (6) and a memory device (200) to a printer (400)
A general-purpose processor (6) that has a path to send the image data and background data stored in the printer (400) and has a function (Op10 to Op13) to correct the write data to the printer (400) and can access the memory device (MEM) ) Creates a reduced image of the data accumulated from the image data in the memory, calculates the background level, and corrects the write data correction block (O
An image processing apparatus comprising means (Op10) for removing the background using p10 to Op13) (FIGS. 3 and 9).

According to this, for the data after the scanner correction, image data in the memory is thinned out in advance to create a reduced image, and the background detection processing (O
psa), it is possible to perform relatively fast and highly accurate background detection.

(8) A device (200) for reading a document surface and converting it to a digitally converted image signal, a device (IPU) for correcting read scanner data and smoothing and thinning in the main scanning direction, and a corrected scanner A memory device (ME) that has a path to transmit the data and the smoothed and thinned scanner data to the memory (MEM), and stores the data
M) and general-purpose processor that can operate data in memory
(6) and a path for sending the image data and background data stored from the memory device (MEM) to the printer (400).
Function to correct the data written to (400) (Op10 to Op1
Means for calculating a background level (Opsc) from data accumulated after smoothing thinning by a general-purpose processor (6) that can access a memory device (MEM) in a device having 3) and removing the background with a correction block of write data An image processing apparatus comprising (Op10) (FIGS. 12 and 13).

According to this, since the smoothing and thinning (12b: Opsb) are performed by the scanner correction unit (IPP) capable of high-speed calculation before writing to the memory, the speed can be increased.

(9) In the above (8), after performing IIR type digital filter processing (formula) in the sub-scanning direction (y) on the reduced image data obtained by smoothing and thinning, in the main scanning direction
An image processing apparatus (FIGS. 14 and 15) having a path (12b, 12c: Opsd) for transmitting scanner data subjected to (x) smoothing and thinning to a memory device (MEM).

According to this, the IIR filter processing (formula) for smoothing in the sub-scanning direction (y) which is the background tracking processing in the sub-scanning direction (y), which is a part of the background detection processing, is performed by scanner correction. Since it is performed by the IPP, it is possible to further improve the background detection accuracy and increase the speed.

(10) At least image data of interest (ID
n) and the background level (JODn-1) defined by the image data preceding the target image data
Expression), the background level (JOD)
n) is calculated.

According to this, attention image data (IDn)
A background level (JODn) is determined, and the background level (JODn) indicates a uniform or smoothed change in the image data when viewed in the sequential switching flow of the image data of interest. A dark level (high level) is a light level (low level) in an area where the background is light. By adjusting the value of the weight K given to the image data of interest (IDn), a background level (JODn) that follows only a background density change having a long fluctuation cycle other than a level fluctuation in each pixel or several pixel groups corresponding to an image. Is obtained. This background level (JODn), primary background level (JODn)
n) is closely related to the image level, so in the preferred embodiment, the adjustment value M such that 0 <M <1 is applied to the primary background level (JODn) in order to provide an offset from the image level. Multiply by the secondary background level (M · JODn).

The background level addressed to the target image data (IDn) is thus generated by smoothing or smoothing the preceding image data including the target image data (IDn), and following the image data in pixel units. Since the background level is updated, the reliability of representing the background of image data representing an image in which the background level variation is relatively wide such that there is a background level variation even on one line is high.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 shows the outline of the mechanism of the first embodiment. This example is
It is a digital full-color copier. A color image reading device (hereinafter, referred to as a scanner) 200 converts an image of the original 180 on the contact glass 202 into an illumination lamp 205,
An image is formed on the color sensor 207 via the mirror groups 204A, 204B, 204C, etc., and the lens 206, and the color image information of the original is converted into, for example, blue (hereinafter, referred to as B), green (hereinafter, referred to as G) and red. (Hereinafter referred to as R) for each color separation light, and is converted into an electric image signal. The color sensor 207 is, in this example,
It is composed of a three-line CCD sensor and reads B, G, and R images for each color. B, G obtained by the scanner 200,
Based on the color separation image signal intensity level of R, color conversion processing is performed by an image processing unit (not shown), and black (hereinafter, referred to as Bk), cyan (hereinafter, referred to as C),
Magenta (hereinafter referred to as M) and yellow (hereinafter referred to as Y
) Is obtained.

Using the color image data, a color image recording device (hereinafter referred to as a color printer) 4 described below
00, the images of Bk, C, M, and Y are superimposed on the intermediate transfer belt and transferred to a transfer sheet. The scanner 200 receives the scanner start signal at the same timing as the operation of the color printer 400, and
Illumination / mirror optical system including mirror group 05, mirror group 204A, 204B, 204C, etc.
Image data of one color is obtained for each scan. Then, each time, while visualizing the images sequentially with the color printer 400, these are superimposed on the intermediate transfer belt to form four full-color images.

A writing optical unit 401 as an exposure unit of the color printer 400 converts color image data from the scanner 200 into an optical signal, performs optical writing corresponding to a document image, and applies an electrostatic charge to the photosensitive drum 414. Form a latent image. The optical writing optical unit 401 includes a laser light emitter 441, a light emission drive control unit (not shown) for driving the light emission, a polygon mirror 443, a rotation motor 444 for rotating the same, a fθ lens 442, a reflection mirror 446, and the like. Have been. Photoconductor drum 414
Rotates in the counterclockwise direction as indicated by the arrow, around which is a photoconductor cleaning unit 421, a neutralization lamp 414M, a charger 419, a potential sensor 414D for detecting a latent image potential on the photoconductor drum, A selected developing device of the revolver developing device 420, a development density pattern detector 414P, an intermediate transfer belt 415, and the like are arranged.

The revolver developing device 420 includes a BK developing device 420K, a C developing device 420C, an M developing device 420M, and a Y developing device 420Y. Each of the developing devices is rotated in a counterclockwise direction as indicated by an arrow. (Not shown). In order to visualize the electrostatic latent image, each of these developing devices rotates developing sleeves 420 KS and 420 which rotate by contacting the ears of the developer with the surface of the photosensitive drum 414.
Assemble the developer with CS, 420MS, 420YS
It is composed of a developing paddle that rotates for stirring. In a standby state, the revolver developing device 420 is set at a position where development is performed by the BK developing device 420, and when a copying operation is started, reading of BK image data is started by the scanner 200 at a predetermined timing, and this image is read. On the basis of the data, optical writing / latent image formation by laser light starts. Hereinafter, the electrostatic latent image based on the Bk image data is referred to as a Bk latent image. The same applies to each of the C, M, and Y image data. In order to enable development from the tip of this Bk latent image,
Before the leading end of the latent image reaches the developing position of the Bk developing device 420K, the rotation of the developing sleeve 420KS is started to develop the Bk latent image with Bk toner. Thereafter, the developing operation of the Bk latent image area is continued. When the rear end of the latent image passes the Bk latent image position, the developing operation of the next color developing unit is immediately performed from the developing position of the Bk developing unit 420K. The revolver developing device 420 is driven and rotated to the position. This rotation operation is completed at least before the leading end of the latent image based on the next image data arrives.

When the image forming cycle is started, the photosensitive drum 414 rotates counterclockwise as indicated by an arrow, and the intermediate transfer belt 415 is rotated clockwise by a drive motor (not shown). Move. Intermediate transfer belt 41
5, the BK toner image formation, the C toner image formation, the M toner image formation, and the Y toner image formation are sequentially performed, and finally, on the intermediate transfer belt 415 in the order of BK, C, M, and Y. , A toner image is formed. The formation of the BK image is performed as follows. That is, the charger 41
9 uniformly charges the photosensitive drum 414 with a negative charge to about -700 V by corona discharge. Subsequently, the laser diode 441 performs raster exposure based on the Bk signal. When the raster image is exposed in this manner, in the initially exposed portion of the photosensitive drum 414 that is uniformly charged, the charge proportional to the amount of exposure light disappears, and an electrostatic latent image is formed. The toner in the revolver developing device 420 is negatively charged by stirring with the ferrite carrier, and the BK developing sleeve 420KS of the present developing device is charged.
Is biased by a power supply circuit (not shown) with respect to the metal base layer of the photosensitive drum 414 to a potential at which a negative DC potential and an AC are superimposed. As a result, no toner adheres to the portion of the photosensitive drum 414 where the charge remains, and Bk is applied to the portion having no charge, that is, the exposed portion.
The toner is attracted, and a Bk visible image similar to the latent image is formed. The intermediate transfer belt 415 includes a driving roller 415D, a transfer facing roller 415T, and a cleaning facing roller 415.
C and a group of driven rollers, and is driven to rotate by a drive motor (not shown). Now, the photosensitive drum 4
The Bk toner image formed on the belt 14 is transferred onto a surface of an intermediate transfer belt 415, which is driven at a constant speed in a state of contact with the photoconductor, by a belt transfer corona discharger (hereinafter, referred to as a belt transfer unit) 4.
16 transferred. Hereinafter, the transfer of the toner image from the photosensitive drum 414 to the intermediate transfer belt 415 is referred to as belt transfer. Some untransferred residual toner on the photoconductor drum 414 is cleaned by the photoconductor cleaning unit 421 in preparation for reuse of the photoconductor drum 414. The collected toner is stored in a waste toner tank (not shown) via a collection pipe.

On the intermediate transfer belt 415, the toner images of Bk, C, M, and Y, which are sequentially formed on the photosensitive drum 414, are sequentially aligned on the same surface, and a four-color superimposed belt transfer image is formed. After that, batch transfer is performed on transfer paper by a corona discharge transfer device. By the way, the photosensitive drum 41
On the fourth side, the process proceeds to the C image forming process after the BK image forming process.
Starts reading of C image data, and a C latent image is formed by laser light writing using the image data.
The C developing device 420C moves the Bk
After the rear end portion of the latent image has passed and before the leading end of the C latent image has arrived, the rotating operation of the revolver developing device is performed to develop the C latent image with C toner. Thereafter, the development of the C latent image area is continued. When the rear end of the latent image has passed, the revolver developing device 420 is driven in the same manner as in the case of the Bk developing device described above,
C developing device 420C is sent out, and the next M developing device 420M
Is located at the developing position. This operation is also the next M
This is performed before the leading end of the latent image reaches the developing section. In the process of forming the M and Y images, the operations of reading the image data, forming the latent image, and developing are in accordance with the processes of the Bk image and the C image described above, and a description thereof will be omitted.

The belt cleaning device 415U includes an inlet seal, a rubber blade, a discharge coil, and a mechanism for contacting and separating the inlet seal and the rubber blade. 1
After the Bk image of the color is transferred to the belt, while the images of the second, third, and fourth colors are transferred to the belt, the entrance seal, the rubber blade, and the like are separated from the intermediate transfer belt surface by the blade contact / separation mechanism. .

A paper transfer corona discharger (hereinafter, referred to as a paper transfer device) 417 uses an AC corona discharge method to transfer the superposed toner image on the intermediate transfer belt 415 to transfer paper.
+ DC or a DC component is applied to the transfer paper and the intermediate transfer belt.

The transfer paper cassette 482 in the paper supply bank stores transfer papers of various sizes.
The sheet is fed and conveyed in the direction of the pair of registration rollers 418R by 83. Reference numeral 412B2 indicates a paper feed tray for manually feeding OHP paper, thick paper, and the like. At the time when the image formation is started, the transfer paper is fed from any of the paper feed trays, and is waiting at the nip of the pair of registration rollers 418R. Then, when the leading end of the toner image on the intermediate transfer belt 415 approaches the paper transfer unit 417, the registration roller pair 418R is driven so that the leading end of the transfer paper coincides with the leading end of the image, and the paper and the image are transferred. Matching is performed. In this way, the transfer paper is superimposed on the color superimposed image on the intermediate transfer belt, and passes over the paper transfer unit 417 connected to the positive potential. At this time, the transfer paper is charged with a positive charge by the corona discharge current, and most of the toner image is transferred onto the transfer paper. Subsequently, when the transfer paper passes through a separation neutralizer with a neutralization brush (not shown) disposed on the left side of the paper transfer unit 417, the transfer paper is neutralized, and the intermediate transfer belt 415 is removed.
From the paper transport belt 422. The transfer paper on which the four-color superimposed toner image has been collectively transferred from the intermediate transfer belt surface is conveyed to a fixing device 423 by a paper conveyance belt 422, and the toner is conveyed to a nip portion between a fixing roller 423A and a pressure roller 423B controlled to a predetermined temperature. The image is fused and fixed
The paper is sent out of the main body by the discharge roll pair 424, and is stacked face up on a copy tray (not shown).

The photosensitive drum 414 after belt transfer
Has its surface cleaned by a photoconductor cleaning unit 421 including a brush roller, a rubber blade, and the like.
Further, the charge is uniformly removed by the charge removing lamp 414M. Further, the intermediate transfer belt 415 after transferring the toner image to the transfer paper
Again, the blade is pressed by the blade contact / separation mechanism of the cleaning unit 415U to clean the surface.
In the case of the repeat copy, the operation of the scanner and the image formation on the photoconductor are continued from the first-color image process on the first sheet, and then proceed to the first-color image process on the second sheet at a predetermined timing. In the case of the intermediate transfer belt 415, the second Bk toner image is belt-transferred to an area whose surface has been cleaned by the belt cleaning device, following the batch transfer process of the first four-color superimposed image onto transfer paper. So that Thereafter, the operation is the same as that of the first sheet.

The color copying machine shown in FIG. 1 is provided from a host such as a personal computer via a LAN or a parallel I / F.
When a print data is provided through the printer, the print data can be printed out (image output) by the color printer 400, and the image data read by the scanner 200 can be transmitted to a remote facsimile, and the received image data can be printed out. It is a color copier. This copier is connected to a public telephone network via a private branch exchange PBX,
Via a public telephone network, facsimile communication and communication with a management server of a service center can be performed.

FIG. 2 shows an electric system of the copying machine shown in FIG. Document scanner 200 for optically reading a document
In the reading unit 4, the reflected light of the lamp irradiation on the document is condensed on the light receiving element 207 by a mirror and a lens in the reading unit 4. The light receiving element (CCD in this embodiment) is provided in a sensor board unit SBU (hereinafter simply referred to as SBU), and an image signal converted into an electric signal in the CCD is a digital signal on the SBU, ie, a read image. After the data is converted to data, the SBU converts the data from the compression / decompression and data interface control unit CDIC (hereinafter simply referred to as CDIC).
).

That is, the image data output from the SBU is input to the CDIC. The transmission of image data between the functional device and the data bus is entirely controlled by the CDIC. In other words, the CDIC uses the SB
U, the parallel bus Pb, and data transfer between the image signal processing device IPP (hereinafter simply referred to as IPP), and image data transfer between the system controller 6 which controls the entire digital copying machine shown in FIG. And communication regarding other controls. The system controller 6 and the process controller 1 communicate with each other via the parallel bus Pb, the CDIC, and the serial bus Sb. The CDIC performs data format conversion for a data interface between the parallel bus Pb and the serial bus Sb inside the CDIC.

Image data read from the SBU is CDI
C, the signal is transferred to the IPP, and the IPP corrects the signal deterioration (signal deterioration of the scanner system: distortion of the read image data due to the scanner characteristics) due to the quantization into the optical system and the digital signal. Output to CDIC is
The image data is transferred to the copy function controller MFC and written in the memory MEM. Alternatively, the processing returns to the IPP processing system for printer output.

That is, the read image data is stored in the CDIC.
A job in which the data is stored in the memory MEM for reuse, and a job in which the data is output to the video data control VDC (hereinafter simply referred to as VDC) without being stored in the memory MEM.
There is a job that performs image formation output at 0. As an example of storing the data in the memory MEM, when a plurality of originals are copied, the reading unit 4 is operated only once to read the read image data.
Data is stored in the memory MEM, and the stored data is read a plurality of times. As an example without using the memory MEM,
When copying only one original, it is only necessary to process the read image data as it is for the printer output, and there is no need to write the data in the memory MEM.

First, when the memory MEM is not used, the IP
The image data transferred from P to CDIC is
C returns to IPP. Image quality processing (FIG. 3) for converting luminance data by CCD into area gradation in IPP
15) is performed. The image data after the image quality processing is transferred from the IPP to the VDC. For the signal changed to the area gradation,
Post-processing relating to dot arrangement and pulse control for reproducing dots are performed by VDC, and a reproduced image is formed on transfer paper in the image forming unit 5 of the laser printer 400.

When the data is stored in the memory MEM and additional processing such as rotation in the image direction and synthesis of the image are performed at the time of reading from the memory MEM, the data transferred from the IPP to the CDIC passes from the CDIC via the parallel bus Pb. And transmitted to an image memory access control IMAC (hereinafter simply referred to as IMAC). Here, access control of the image data and the memory module MEM (hereinafter simply referred to as MEM) is performed based on the control of the system controller 6, and an external personal computer PC
It expands print data (hereinafter simply referred to as PC) (character code / character bit conversion) and compresses / decompresses image data for effective use of memory. The data sent to the IMAC is stored in the MEM after data compression, and the stored data is read as necessary. The read data is expanded, returned to the original image data, and returned from the IMAC to the CDIC via the parallel bus Pb.

After the transfer from the CDIC to the IPP, the IPP
The image forming unit 5 performs the image processing and the pulse control with the VDC, and the image forming unit 5 forms a visible image (toner image) on the transfer paper.

In the flow of the image data, the composite function of the digital copying machine is realized by the bus control by the parallel bus Pb and the CDIC. The FAX transmission function, which is one of the copying functions, transmits the image data read by the scanner 200 to the IPP.
Performs image processing on CDIC and parallel bus Pb
FAX control unit FCU (hereinafter simply referred to as FCU)
(Referred to as). Public line communication network PN at FCU
(Hereinafter simply referred to as PN), and the data is transmitted to the PN as FAX data. In FAX reception, line data from the PN is converted into image data by the FCU, and is transferred to the IPP via the parallel bus Pb and the CDIC. In this case, no special image quality processing is performed, dot rearrangement and pulse control are performed in the VDC, and a visible image is formed on the transfer paper in the image forming unit 5.

In a situation where a plurality of jobs, for example, a copy function, a facsimile transmission / reception function and a printer output function, operate in parallel, the allocation of the reading unit 4, the imaging unit 5, and the right to use the parallel bus Pb to the job is performed by the system. It is controlled by the controller 6 and the process controller 1.

The process controller 1 controls the flow of image data, and the system controller 6 controls the entire system and manages activation of each resource. This digital copying function is selected and input on the operation board OPB to select the function of the copying machine, and set the processing contents such as the copying function and the FAX function.

FIG. 3 shows an outline of the image processing function of the IPP. The read image data is transmitted from the SBU via the CDIC to the scanner image processing 12 from the input I / F (interface) 11 of the IPP. Scanner image processing 12 is mainly intended to correct the deterioration of image information due to reading.
Performs shading correction, show-through correction, scanner γ correction, MTF correction, and the like. Although not a correction process, a scaling process for enlargement / reduction is also performed. After the correction processing of the read image data is completed, the image data is transferred to the CDIC via the output I / F 13. For output to transfer paper, image data from the CDIC is received from the input I / F 14, and area gradation processing is performed in the image quality processing 15c. The data after image quality processing is output I /
Output to VDC via F16. Area gradation processing is
There are density conversion, dither processing, error diffusion processing, and the like, and the main processing is area approximation of gradation information.

Once the image data subjected to the scanner image processing 12 is stored in the memory MEM, various reproduced images can be confirmed by changing the processing performed in the image quality processing 15. For example, try shaking the density of the reproduced image,
The atmosphere of the reproduced image can be changed by changing the number of lines of the dither matrix. At this time, it is not necessary to read the image again by the scanner 200 every time the processing is changed.
If the stored image is read from the EM, different processing can be performed on the same data any number of times.

When the background level is removed, as shown in FIG. 3, the image data input from the scanner 200 is subjected to the scanner image correction by the IPP via the CDIC. Scanner data after image correction is CDIC, I
It is stored in the MEM via the MAC. The data in the MEM can be operated by the system controller 6 connected to the IMAC. The background level is detected by the system controller 6.

However, since the system controller 6 is a general-purpose processor, the operation speed is low. Therefore, as data for background detection, pixels are thinned out at regular intervals in the main scanning direction and managed separately from the original image. Since the scanner of this embodiment assumes 600 dpi, even if it is thinned out at intervals of 4 pixels and 150 dpi (reduction of 1/4 in the main scanning x direction: skipping 3 pixels and extracting 1 pixel), the accuracy of background detection is almost zero. Not affected. The system controller 6 is a MEM
1/4 of the image data read from the image data is thinned out to obtain reduced image data.
The image data and background level data read from M are returned to IPP via IMAC and CDIC, respectively.

The background level data is 1/4 in the main scanning direction x.
, The main scan is enlarged inside the IPP (see FIG. 3).
15a) is performed. Then, the background removal processing is performed inside the IPP (15b in FIG. 3).

The calculation of the background level by the system controller 6 and the background removal processing of the IPP will be described later in further detail.

FIG. 4 shows an outline of the internal configuration of the IPP. I
The PP has a plurality of input / output ports with respect to data input / output with the outside, and inputs and outputs can be set arbitrarily, respectively. A local memory group is provided inside, and a memory control unit controls a memory area to be used and a data path. For the input data and the data for output, a local memory group is allocated as a buffer memory, stored in each, and an I / F with the outside is controlled. Various processing is performed on the image data stored in the local memory in the processor array unit, and the output result is stored again in the local memory. The processing procedure of the processor, parameters for the processing, and the like are exchanged between the program RAM and the data RAM. The contents of the program RAM and data RAM are downloaded from the process controller via the serial I / F. Alternatively, the process controller reads the contents of the data RAM and monitors the progress of the processing.
When the contents of the processing are changed or the processing form required by the system is changed, the contents of the program RAM and the data RAM referred to by the processor array are updated and corresponded.

FIG. 5 shows an outline of a functional configuration of the CDIC. The image data input / output control 21 inputs the read image data from the SBU and outputs the data to the IPP. The image data input controller 22 receives the image data subjected to the scanner image correction by the scanner image processing 12 by the IPP. The input data is subjected to data compression in the data compression unit 23 in order to increase the transfer efficiency on the parallel bus Pb. The compressed image data is parallel data I /
It is sent to the parallel bus Pb via F25. Image data input from the parallel data bus Pb via the parallel data I / F 25 is compressed for bus transfer, and is expanded by the data expansion unit 26. The decompressed image data is transferred to the IPP by the image data output control 27. The CDIC has a function of converting parallel data and serial data. System controller 6
Transfers data to the parallel bus Pb, and the process controller 1 transfers data to the serial bus Sb.
For communication between the two controllers 6 and 1, the data conversion unit 24 and the serial data I / F 29 use a parallel /
Performs serial data conversion. Serial data I / F28
Are for IPP, and also perform serial data transfer with IPP.

FIG. 6 shows an outline of a functional configuration of the VDC.
The VDC performs additional processing on the image data input from the IPP according to the characteristics of the imaging unit 5. The rearrangement process of the dots by the edge smoothing process and the pulse control of the image signal for the dot formation are performed, and the image data is output to the image forming unit 5. Apart from the conversion of the image data, it has the parallel data and serial data format conversion functions 33 to 35, and the VDC alone can support the communication between the system controller 6 and the process controller 1.

FIG. 7 shows an outline of the functional configuration of the IMAC. The parallel data I / F 41 manages input / output of image data to / from the parallel bus Pb, stores / reads image data to / from the MEM, and converts code data mainly input from an external PC to image data. Control deployment. The code data input from the PC is stored in the line buffer 42. That is, the data is stored in the local area, and the code data stored in the line buffer 42 is supplied to the video controller 43 based on the expansion processing command from the system controller 6 input via the system controller I / F 44. Expand to image data.
Expanded image data or parallel data I / F4
The image data input from the parallel bus Pb via the P1 is stored in the MEM. In this case, the data conversion unit 45
In step (2), image data to be stored is selected, data compression is performed in the data compression section 46 to increase the memory use efficiency, and image data is stored in the MEM while the memory access control section 47 manages the address of the MEM. I do.
When reading the image data stored in the MEM, the memory access control unit 47 controls the read destination address, and the read image data is expanded by the data expansion unit 48. When transferring the expanded image data to the parallel bus Pb, the data transfer is performed via the parallel data I / F 41.

FIG. 8 shows an outline of the functional configuration of the FCU. F
The AX transmission / reception unit FCU converts the image data into a communication format and transmits it to the external line PN, and converts the data from the external line PN back to the image data and creates the image data via the external I / F unit 51 and the parallel bus Pb. The image is recorded and output in the image unit 5. The FAX transmitting / receiving unit FCU includes a FAX image processor 52, an image memory 53, a memory control unit 55, a facsimile control unit 54, an image compression / decompression 56, a modem 57, and a network control device 5.
Consists of eight. Among them, regarding the FAX image processing 52, the binary smoothing processing on the received image is performed in the edge smoothing processing 31 of the VDC. As for the image memory 53, a part of the output buffer function is completed by the IMAC and the MEM.

FAX transmission / reception unit FCU thus configured
Then, when the transmission of the image information is started, the facsimile control unit 54 instructs the memory control unit 55 and the image memory 53
, The stored image information is sequentially read. The read image information is restored to the original signal by the FAX image processing 52, is subjected to density conversion processing and scaling processing, and is applied to the facsimile control unit 54. The image signal applied to the facsimile control unit 54 is code-compressed by the image compression / decompression unit 56, modulated by the modem 57, and transmitted to the destination via the network control device 58. The transmitted image information is stored in the image memory 5.
3 is deleted.

At the time of reception, the received image is temporarily stored in the image memory 5.
3, if the received image can be recorded and output at that time, it is recorded and output when the reception of one image is completed. When a call is made during the copying operation and reception starts, the image memory 53 is stored in the image memory 53 until the usage rate of the image memory 53 reaches a predetermined value, for example, 80%.
When the usage rate reaches 80%, the writing operation being executed at that time is forcibly interrupted, and the received image is read from the image memory 53 and recorded and output. At this time, the received image read from the image memory 53 is deleted from the image memory 53, and the usage rate of the image memory 53 becomes a predetermined value, for example, 10
When the writing operation has been suspended, the writing operation which has been interrupted is resumed, and when all the writing operations have been completed, the remaining received image is recorded and output. Further, after the write operation is interrupted, various parameters for the write operation at the time of the interruption are internally saved so that the write operation can be resumed, and the parameters are internally restored at the time of restart.

In the above example, the CDIC as the image bus management unit and the IMAC as the memory management unit are connected by a parallel bus Pb as a set of image buses. The independent SBU as image reading means, VDC as writing means and IPP as image signal processing means are connected directly to image bus management means CDI without being directly connected to image bus Pb.
C, the use management of the image bus Pb is substantially controlled by the image bus management means CDIC and the memory management means IMA.
Only done by C. Therefore, arbitration and transfer control of the bus Pb are easy and efficient.

FIG. 9 shows a flow of a process of storing an image in the MEM and a process of reading an image from the MEM. (a)
Is a processing or transfer process Ip of the image data until the image data generated by the image scanner 200 is written into the MEM.
(B) shows the processing or transfer process Op1 to Op13 of the image data from reading out the image data from the MEM to outputting it to the printer 400.

System controller 6 via CDIC
Controls the data flow between such buses and units. Regarding the read image data, the scanner image processing Ip1 to Ip13 in the IPP (FIG.
12) is applied to the image data to be output to the printer 400 with the image quality processing Op1 to Op13 (FIG.
15a to 15c) are carried out independently.

In the present embodiment, the “thinning and background calculation” Opsa and the “main scanning enlargement and background removal processing” Op10 shown by block divisions in FIG. 9B are read out from the MEM to the printer 400. Output process Op1
In Op13, the system controller 6 and the IPP respectively perform the processing.

When the image data is read out from the MEM and sent to the printer output path, the system controller 6 performs the “thinning-out & background calculation” Opsa. In this case, from the image data read from the MEM and decoded and expanded by the IMAC, the image data is thinned out to 1/4 in the main scanning direction, extracted, subjected to simple smoothing filter processing (calculation of an average value), and The primary background level JODn is calculated as follows: JODn = (1−K) · JODn−1 + K · IDn... JODn: Density after calculation at the nth pixel in the main scanning direction (primary background level) IDn: Main scanning Input image density of the nth pixel in the direction (image data to be processed) K: Follow-up coefficient (0 <K ≦ 1); “adjustment” of operation unit OPB
A processing characteristic adjustment parameter whose value can be adjusted by operating a key, where "." Means multiplication and "/" means division. The same applies to the following. The pixel here is a pixel obtained by extracting image data, and the image data is reduced image data obtained by thinning out and performing a smoothing filter process.

FIG. 10A shows an example of image data IDn to be processed, the calculated primary background level JODn, and the following secondary background level M · JODn. The background level calculation value JODn is calculated based on the value of the weight K and the original data IDn.
The speed of following changes. As can be seen from the equation, K
Is larger, the closer to the original data IDn, the higher the following speed. The smaller K is, the slower the following speed becomes, and it becomes closer to a constant value. By appropriately adjusting the value of K, FIG.
It is possible to obtain the primary background level JODn that follows only a large change in the background other than the peak as shown in FIG.

The primary background level data JODn is supplied to the IPP in synchronization with the readout data without thinning-out and the timing (position on the image).

In the first embodiment, the original image data is thinned out in the main scanning direction on the MEM to generate image data for background detection and background detection is performed on the image data. 6, the background detection process can be performed at a relatively high speed.

IPP stands for “main scanning enlargement & background removal processing”.
In Op10, one primary background level data JODn is converted into four primary background level data J of the same value in the main scanning direction x.
ODm is assigned to each image data read from the MEM. This is the main scanning magnification at the background level. Then, primary image data AODm obtained by subtracting (removing) the background level assigned to each image data.
Is calculated as follows: AODm = IDm−M · JODm... IF (AODm <0) THEN AODm = 0 M: Background density calculation coefficient (0 <M ≦ 1); From the original image data IDm, a processing characteristic adjustment parameter that can adjust the value, that is, a secondary background level M · JODm which is a product of the primary background level JODm and the adjustment coefficient M is subtracted. FIG. 10B shows an example of the primary image data AODm. FIG. 10A shows the reduced image data. (B) of FIG.
Since it corresponds to the original same-size image data, the amount of image data per line is four times as large as the reduced image data of FIG. hand,
This means that the data is shown compressed to 1/4.

Although the background removal is completed, the density of the background removal M · JODm is reduced as it is, and the legibility is deteriorated especially in the case of characters and the like. For this reason, the contrast is corrected in the next image quality processing Op11, and the level of the full scale value is increased to near the maximum value of the number of image data bits.

The above “main scanning enlargement & background removal processing” Op
One of the features is that since the correction of 10 and the contrast can be completely expressed by an arithmetic expression, it is suitable for processing by a digital signal processor (DSP) such as an IPP.

FIG. 15 shows a SIMD (Single Instruction Stream Multi-Data std) for image processing adopted in the IPP.
1 shows a schematic configuration of a (ream) type processor. The SIMD executes a single instruction in parallel with respect to a plurality of data, and is composed of a plurality of (eight in the illustrated example for one-byte parallel processing) PEs (processor elements) PE1 to PE8. Each PE has a register (R
eg), a multiplexer (MUX) for accessing a register of another PE, a barrel shifter (Shift Expan)
d), a logical operation unit (ALU), an accumulator (A) for storing a logical result, and a temporary register (F) for temporarily comparing the contents of the accumulator. Each register is connected to an address and a data bus, and stores an instruction code defining a process or data to be processed.

The data to be processed by the register is AL
It is input to U, and the result of the arithmetic processing is stored in A. The result is temporarily saved in F to be taken out of the PE.
By extracting the contents of F, a processing result for the target data can be obtained. The instruction code is given to each PE with the same content, the data to be processed is given in a different state for each PE,
By referring to the contents of the Reg in the MUX, the calculation results are processed in parallel and output to each A. For example, image data 1
By arranging the contents of the line in the PE for each pixel and performing arithmetic processing with the same instruction code, a processing result of one byte can be obtained in a shorter time than processing one pixel at a time. IPP
Is performed by these PEs.

-Second Embodiment- In the second embodiment, as shown in FIG. 12, a "main scan reduction" function 12b (Opsb in FIG. 13) for smoothing and thinning the main scan is added to the IPP. Things. As shown in FIG. 12, the input image data is transmitted to the
Scanner image correction is performed in PP. The scanner data subjected to the image correction is directly stored in the MEM via the CDIC and IMAC, and the reduced image data obtained by performing smoothing and thinning in the main scanning direction by the “main scanning reduction” 12b inside the IPP. Some are stored in the MEM. Since the reduction is performed by smoothing and thinning out the main scanning, the average density is stored. Therefore, when the background level is determined inside the MEM, the background level can be accurately determined.

FIG. 13 shows a flow of processing for storing an image in the MEM and processing for reading an image from the MEM in the second embodiment. (a) shows image data processing or transfer processes Ip1 to Ip13 until image data generated by the image scanner 200 is written into the MEM, and (b) shows MEM.
From the image data until the image data is output to the printer 400.
p13 is shown. As in the first embodiment, the data flow between the bus and the unit is controlled by the control of the system controller 6 via the CDIC.

In the second embodiment, the IPP performs “main scanning reduction” Opsb, which is indicated by block divisions in FIG. Then, the “background calculation” Opsc and the “main scanning enlargement & background removal processing” Op10 are performed in steps Op1 to Op13 in which image data is read from the MEM and output to the printer 400.
At the same time, the reduced image data is also read from the MEM, and is performed by the system controller 6 and the IPP, respectively.

When reading the image data from the MEM and sending it to the printer output path, the system controller 6 performs “background calculation” Opsc. In this case, as in the first embodiment, the primary background level JODn
Is calculated. IPP “Main scan enlargement & background removal processing”
The contents of the processing of Op10 and below are the same as in the first embodiment.

In the second embodiment, since the reduced image is created by thinning out inside the IPP, the system controller 6 can concentrate on the calculation of the background level, lightening the processing load and contributing to speeding up.

-Third Embodiment- In the second embodiment, as shown in FIG. 14, a "main scanning reduction" function 12b for performing main scanning smoothing and thinning and an "IIR filter" processing function 12c (see FIG. 14). (Opsd in Fig. 15)
Is added. As shown in FIG. 14, the input image data is subjected to scanner image correction by IPP via CDIC. The scanner data subjected to the image correction is directly stored in the MEM via the CDIC and the IMAC, and after the smoothing and the thinning-out 12b in the main scanning direction are performed inside the IPP, the data in the sub-scanning direction by the IIR filter is performed. Some are subjected to the smoothing 12c and stored in the MEM.

The IIR filter here performs the operation of the expression in the sub-scanning direction rotated by 90 degrees. That is, the smoothing level (y background level) addressed to the attention image data is calculated by weighting and adding the smoothing level (y background level) defined by the image data of interest and the image data of the line preceding the image data of interest. . Since the smoothing level of the preceding line is required, the line buffer 12d
The calculated smoothing level is updated and written in the line buffer 12, and is stored in the memory MEM in association with the original (actual-size) image data at the corresponding position.

Since the reduction is performed by smoothing and thinning out the main scanning, the average density is preserved. Further, since the IIR filter is applied in the sub-scanning direction and then passed to the MEM, the background level can be more accurately obtained when the background level is obtained inside the MEM.

FIG. 15 shows a flow of a process of storing an image in the MEM and a process of reading an image from the MEM in the third embodiment. (a) shows image data processing or transfer processes Ip1 to Ip13 until image data generated by the image scanner 200 is written into the MEM, and (b) shows MEM.
From the image data until the image data is output to the printer 400.
p13 is shown. As in the first embodiment, the data flow between the bus and the unit is controlled by the control of the system controller 6 via the CDIC.

In the third embodiment, the IPP performs “main scan reduction & y background calculation” Opsd, which is indicated by block divisions in FIG. The contents are as described above (12b to 12d in FIG. 14). Then, “x background calculation” Opse and “main scanning enlargement & background removal processing” Op10 are performed in steps Op1 to Op13 in which image data is read from the MEM and output to the printer 400. It is read and performed by the system controller 6 and the IPP, respectively.

When reading the image data from the MEM and sending it to the printer output path, the system controller 6 performs “x background calculation” Opse. In this,
As in the first embodiment, the primary background level JOD is calculated using the above equation.
Calculate n. Here, the original data IDn is smoothing level (y background) data. IPP's "Main Scan Enlargement & Background Removal" Op10
This is the same as the first embodiment.

In the third embodiment, since reduced image data is created by thinning and smoothed in the sub-scanning direction is also performed inside the IPP, after accumulation in the MEM, the background is smoothed in the main scanning direction. , And the processing load on the system controller 6 is reduced, which contributes to speeding up. The tracking in the sub-scanning direction (y background detection)
, Which enables more accurate background detection.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an outline of a mechanism of a digital color copying machine according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an outline of a configuration of an electric control system of the copying machine shown in FIG.

FIG. 3 is a block diagram illustrating a functional configuration of the image signal processing device IPP illustrated in FIG. 2;

FIG. 4 is a block diagram showing an outline of hardware of the image signal processing device IPP shown in FIG. 2;

5 is a block diagram showing a functional configuration of a compression / decompression and data interface control unit CDIC shown in FIG. 2;

FIG. 6 is a block diagram showing a functional configuration of a video data control VDC shown in FIG. 2;

7 is an image memory access control IMAC shown in FIG.
FIG. 2 is a block diagram showing a functional configuration of the first embodiment.

FIG. 8 is a block diagram illustrating a functional configuration of a facsimile transmitting / receiving unit FCU illustrated in FIG. 2;

9A is a flowchart showing the flow and processing of image data until the image data read by the scanner 200 shown in FIG. 2 is written into the image memory MEM; FIG.
9 is a flowchart showing the flow and processing of image data from reading image data from the image memory MEM to outputting the image data to the printer 400.

FIG. 10A shows image data IDn obtained by reading a document in which a dark background and a light background are mixed by a scanner 200, the primary background level JODn, and the secondary background level M · J.
It is a graph which shows ODn typically. (B)
From the image data IDn shown in FIG.
It is a graph which shows the image data AODn after background removal which subtracted JODn.

FIG. 11 is a block diagram showing a partial configuration of a processor array PAU shown in FIG. 4;

FIG. 12 is a block diagram illustrating an outline of a functional configuration of an image signal processing device IIP used in a second embodiment of the present invention.

FIG. 13A is a flowchart showing the flow and processing of image data until image data read by a scanner is written into an image memory MEM in the second embodiment.
FIG. 4B is a flowchart showing the flow and processing of image data from reading image data from the image memory MEM to outputting the image data to the printer.

FIG. 14 is a block diagram illustrating an outline of a functional configuration of an image processing apparatus IIP used in a third embodiment of the present invention.

FIG. 15A is a flowchart showing the flow and processing of image data until image data read by a scanner is written into an image memory MEM in the third embodiment;
FIG. 4B is a flowchart showing the flow and processing of image data from reading image data from the image memory MEM to outputting the image data to the printer.

[Explanation of symbols]

200: Document scanning scanner 400: Full color printer IPP: Image signal processing device CDIC: Compression / decompression and data interface control unit VDC: Video data control IMAC: Image memory access control FCU: FAX transmission / reception unit SBU ： Sensor-Bo
Do Unit PN: Public line

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Maki Oyama 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 5B047 AA01 AB04 BA02 BB02 DA03 DC01 EB04 5C076 AA22 BA03 BA04 BB01 5C077 LL18 MP05 MP08 PP02 PP20 PP25 PQ12 PQ18 PQ22 RR19 RR21 TT06

Claims (6)

[Claims] An image reading means reads an image, converts the image data into image data, corrects the image data, accumulates the corrected image data in a memory means, extracts or generates reduced image data from the accumulated image data, and forms a background image based on the reduced image data. An image reading processing method for generating level data and converting the image data read from the memory means into image data from which the background level represented by data obtained by expanding the background level data so as to correspond to the same size image is removed. 2. An image reading device reads an image, converts the image data into image data, corrects the image data and stores the corrected image data in a memory device, and extracts or generates reduced image data from the corrected image data and stores the reduced image data in the memory device. Then, the image data and the reduced image data are read from the memory means, and the background level data is generated based on the reduced image data, and the image data read from the memory means is expanded so that the background level data corresponds to the same-size image. An image reading processing method for converting a background level represented by data into image data from which the background level has been removed. 3. An image reading device reads an image, converts the image data into image data, corrects the image data and accumulates the corrected image data in a memory device, and extracts or outputs reduced image data reduced in the main scanning direction from the corrected image data. Generated and smoothed in the sub-scanning direction addressed to the focused reduced image data by weighted addition of at least the focused reduced image data and a smoothing level defined by the reduced image data preceding the focused reduced image data in the sub-scanning direction A level is obtained and stored in a memory means, the image data and the smoothing level are read out from the memory means, and ground level data obtained by smoothing it in the main scanning direction based on the smoothing level is generated. Image data obtained by removing the background level represented by data obtained by expanding the background level data corresponding to the same size image as the read image data. Converting, image reading processing method. 4. The method according to claim 1, wherein the extraction or generation of the reduced image data includes smoothing of the image data in the main scanning direction and extraction of the smoothed image data skipping in the main scanning direction. 3. The image reading processing method according to 3. 5. An image reading means for reading an image and converting it into digitized image data; an image processing means for correcting the image data; a memory device for storing data; Reduction processing means for extracting reduced image data reduced in the main scanning direction; once writing the image data corrected by the image processing means into the memory device and reading out the image data, the background level is calculated from the reduced image data. Means for generating data; and means for converting the image data read from the memory device into image data from which the background level represented by data obtained by expanding the background level data for a 1: 1 image is removed. An image reading device comprising: 6. An image reading apparatus according to claim 5, and
A printer for forming an image represented by the image data from which the background level has been removed on a sheet of paper.