JP2002185767A - Image processing unit and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit and method that eliminates the effect of dust or the like onto an image signal so as to obtain a proper image at all times. SOLUTION: The image processing unit is provided with image read means 4, 5, 103 that read an original 1001, image processing means 104-107, 110, 120 that process image signals obtained by the image read means, a recognition means 1002 that recognizes presence of information other than original image information according to the result of the processing by the image signal processing means, and an image signal correction means 106 that corrects the image signal obtained by the image read means depending on the result of the recognition by the recognition means. The recognition means recognizes the position of dust superimposed on the image of an original.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and method for recording, transmitting, and storing an image signal obtained by optically scanning a document, such as a so-called digital copying machine.

[0002]

2. Description of the Related Art In an image reading scanner constituting a digital copying machine or the like, a stationary reading method in which a document image placed on a document table is exposed and scanned by a sensor and scanned, and an automatic document feeder (hereinafter referred to as "ADF"). (Abbreviation), there are two types of flow reading methods for reading an image while feeding a document onto a platen glass at a constant speed.

[0003]

In the latter case, in particular,
Since a fixed linear area on the platen glass is exposed by a light source and read by a sensor, if dust adheres on the read line, a streak line is superimposed on the read image, causing a problem.

The present invention has been made in view of the above circumstances, and has as its object to provide an image processing apparatus and method capable of always obtaining a proper image without affecting the image signal due to dust or the like.

[0005]

According to the present invention, there is provided an image processing apparatus comprising: an image reading means for reading an original; an image signal processing means for processing an image signal obtained by the image reading means; A recognition unit that recognizes the presence of information other than the document image information from the processing result; and an image signal correction unit that corrects an image signal obtained by the image reading unit according to the recognition result of the recognition unit. And

In the image processing apparatus according to the present invention, the recognition means recognizes the presence of dust superimposed on the original image. In the image processing apparatus according to the present invention, the recognition unit recognizes a position of dust superimposed on the document image.

Further, in the image processing apparatus according to the present invention, the image signal processing means performs a threshold process on the image signal.

Further, in the image processing apparatus according to the present invention, the recognizing means generates a histogram from the processing result of the image signal processing means, and performs a threshold process on a cumulative frequency obtained from the histogram. Further, in the image processing apparatus according to the present invention, the recognition by the recognition means is performed on a plurality of documents, and the presence of information other than the document image information is recognized from the recognition result for each document.

Further, in the image processing apparatus according to the present invention, the image signal correcting means corrects information other than the document image information into document image information.

Further, the image processing apparatus according to the present invention is characterized in that the image processing apparatus further comprises information output means for outputting information corresponding to the recognition result to the operator according to the recognition result of the recognition means.

In the image processing apparatus according to the present invention, the recognizing means for any one of the color-separated color image signals; The image signal correcting means for correcting a signal.

Further, the image processing method according to the present invention provides an image reading step for reading a document, an image signal processing step for processing an image signal obtained in the image reading step, and a document processing method based on the processing result of the image signal processing step. A recognition step of recognizing the presence of information other than image information; and an image signal correction step of correcting an image signal obtained in the image reading step according to a recognition result of the recognition step.

Further, in the image processing method according to the present invention, in the recognition step, the presence of dust superimposed on the original image is recognized. Further, in the image processing method of the present invention, the position of dust superimposed on the document image is recognized in the recognition step.

Further, in the image processing method according to the present invention, the image signal is subjected to threshold processing in the image signal processing step.

Further, in the image processing method according to the present invention, in the recognition step, a histogram is created from the processing result of the image signal processing step, and a cumulative frequency obtained by the histogram is subjected to threshold processing. Further, in the image processing method of the present invention, the recognition in the recognition step is performed on a plurality of documents, and the presence of information other than the document image information is recognized from the recognition result for each document.

Further, in the image processing method of the present invention, in the image signal correcting step, information other than the document image information is corrected into document image information.

Further, the image processing method according to the present invention is characterized in that the method further comprises an information output step of outputting information corresponding to the recognition result to the operator according to the recognition result of the recognition step.

Further, in the image processing method of the present invention, the recognition step for any of the color-separated color image signals, and the multi-color image obtained in the image reading step according to the recognition result of the recognition step. The image signal correcting step of correcting a signal.

The storage medium of the present invention is a computer-readable storage medium storing a program for causing a computer to function as any one of the above means. Further, a storage medium of the present invention is a computer-readable storage medium storing a program for executing the processing procedure of any of the above methods.

According to the present invention, it is possible to detect a defect of a read image due to dust adhering to the glass of the document table and correct an unnecessary image signal due to dust. As a result, the influence of dust superimposed on the original image on the image signal can be removed, and a proper image can be obtained.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image processing apparatus and method according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration according to this embodiment. Hereinafter, each component will be described together with its operation. The original 1001 passes through the image sensor 5 from the lens 4 of the image reading unit, enters the A / D converter 103 that performs AD conversion, and the signal after the A / D conversion is input to the image processing unit. In the image processing unit, shading correction 1
In step S04, the luminance data is converted into recording density data by the light density conversion circuit 105, which is input to the dust recognition unit 1002, which is a feature of the present invention.

When the position of dust is recognized by a dust recognition unit 1002 described later, the image data correction unit 106
The part affected by dust is corrected and deleted from the image signal obtained by the light density conversion unit 105. The sharpness of the corrected image signal is corrected by the spatial filter unit 110 in accordance with the image mode, and a pseudo halftone processing unit (binarization unit) 1 for binary recording
At 20, the image signal is binarized. The image signal is output from the external IF 121 to an external system such as an external network according to an instruction of the operator, and is also output to the image editing unit 107 for editing various images. The image editing unit 107 performs an editing process based on the data processed according to the image processing settings stored in the RAM 115 in the CPU circuit 113. Then, the edited image data is output to the image recording unit 117.

The image recording unit 117 includes a control circuit such as a motor for transporting transfer paper and the like, a laser recording circuit unit for writing a video signal input from the image processing unit on the photosensitive drum, and a development control circuit for development. It is configured to record an image on a recording medium such as recording paper. The operation unit 116 has various key groups and various LED groups for instructing image editing operations such as image editing contents, the number of copies, and magnification ratio for the image processing unit, and a display unit for displaying the contents at the time of operation. are doing.

FIG. 2 is a sectional view showing the structure of the image recording apparatus according to this embodiment. 2, reference numeral 100 denotes a control unit on which the various circuits shown in FIG. 1 are mounted. Reference numeral 10 denotes an exposure unit that receives an image signal from an image signal control unit (not shown) that generates an image signal based on image data from the image editing unit 107 in the control unit 100, and sends a light beam to the photosensitive member 11. Irradiate. Numerals 12 and 13 denote developing devices for developing the electrostatic latent images formed on the photoreceptor 11 with a developer (toner) of a predetermined color.
Visualize with. Reference numerals 14 and 15 denote transfer paper stacking units, on which recording media of a fixed size are stacked and stored. The recording medium is fed to the position where the registration roller is provided by driving the feeding roller, and is re-fed with the timing of aligning the leading end of the image with the image formed on the photoconductor 11.

Reference numeral 16 denotes a transfer separation charger, which is a photosensitive member 11
After the toner image developed on the paper is transferred to the transfer paper, the toner image is separated from the photoreceptor 11 and fixed by the fixing unit 17 via the transport belt. Reference numeral 18 denotes a paper discharge roller, which stacks and discharges the transfer-receiving paper on which image formation has been completed. Reference numeral 19 denotes a directional flapper, which switches the transport direction of the transfer-receiving sheet on which image formation has been completed between the paper discharge port and the internal transport direction, and prepares for a multiplex / double-sided image forming process.

FIG. 3 shows the operation unit 11 used in this embodiment.
6 is an external view of FIG. In FIG. 3, reference numeral 5001 denotes a power switch for controlling power supply to the apparatus main body. A reset key 5002 operates as a key for returning to the standard mode during standby. Reference numeral 5003 denotes a copy start key. A clear key 5004 is used to clear a numerical value such as the number of copies.

Reference numeral 5005 denotes an ID key. The ID key 5005 allows a specific operator to perform a copying operation, and for other operators, prohibits the copying operation unless an ID is input by the ID key. It becomes possible.
Reference numeral 5006 denotes a stop key, which is used to interrupt or stop copying. Reference numeral 5007 denotes a guide key, which is used when the user wants to know each function. Reference numeral 5008 denotes an up cursor key, which is a key for moving a pointer upward on each function setting screen. 50
Reference numeral 09 denotes a down cursor key, which is used to move a pointer downward on each function setting screen. A right cursor key 5010 is a key for moving the pointer to the right on each function setting screen. A left cursor key 5011 is a key for moving the pointer to the left on each function setting screen. Reference numeral 5012 denotes an OK key, which is depressed on each function setting screen when this is sufficient.

Reference numeral 5013 denotes a key for depressing this key when executing what is output at the lower right of the screen 5052 in each function setting screen. A standard size reduction key 5014 is used to reduce the standard size to another standard size. 5015
Is used to select 1: 1 copy. A standard enlargement key 5016 is used to enlarge the standard size to another standard size. A cassette selection key 5017 selects a cassette stage to be copied.

Reference numeral 5018 denotes a copy density adjustment key for reducing the density. An AE key 5019 automatically adjusts the copy density with respect to the density of the original. A copy density adjustment key 5020 increases the density. 5021 is a key for specifying the operation of the sorter. Reference numeral 5022 denotes a preheating key, which is used to turn on / off a preheating mode. 502
Reference numeral 3 denotes an interrupt key, which is pressed when an interrupt is required to be made during copying. 5024 is a numeric keypad,
Used to enter numerical values.

Preheat key 5022 or interrupt key 5
A plurality of function keys, which will be described below, are arranged in a row on the side of the reference numeral 23. That is, a marker processing key 5025 sets trimming, masking, and partial processing (contour processing, halftone processing, shadowing processing, negative / positive processing).
Reference numeral 5026 denotes a patterning processing key, which is used for expressing a color in a pattern or expressing a color by a density difference. A color erasing key 5027 is used to erase a specific color. An image quality key 5028 is used to set the image quality. Reference numeral 5029 denotes a negative / positive key, which is used when performing negative / positive processing.
5030 is an image create key,
Used when performing shadowing processing, halftone processing, italic, mirror processing, and repeat processing. Reference numeral 5031 denotes a trimming key which is used to designate an area and perform trimming. A masking key 5032 is used to designate an area and perform masking. A partial processing key 5033 specifies an area, and then specifies partial processing (contour processing, halftone processing, shadowing processing, negative / positive processing). Reference numeral 5034 denotes a frame erasing key which is used when erasing a frame in accordance with a mode. The modes are sheet frame erasing (creating a frame for the sheet size), document frame erasing (creating a frame according to the document size, original size is specified), and book frame erasing (frames matching the spread size of the book). Create a blank in the center. Book spread size specified). A binding margin key 5035 is used to create a binding margin at one end of a sheet.

Reference numeral 5036 denotes a movement key for moving an image in a desired area, which is used when moving is desired.
The movement includes parallel movement (up, down, left and right), center movement, corner movement, and designated movement (point designation). 5037
Is a zoom key, which can set a copy magnification from 25% to 400% in increments of 1%. Further, the main scanning and the sub scanning can be set independently. The magnification of the image is controlled by controlling the moving speed of the scanner 3 in the sub-scanning direction of the document, and the image data read out from the scanner 3 is thinned out or interpolated in the main scanning direction of the document.

Reference numeral 5038 denotes an automatic scaling key, which automatically enlarges or reduces the size according to the size of the copy sheet. In addition, the main scanning and the sub-scanning can be automatically scaled independently. Reference numeral 5039 denotes an enlargement continuous shooting key, which is used when one original is enlarged to a plurality of copies and copied. Reference numeral 5040 denotes a reduced layout key, which is used when copying a plurality of originals by enlarging / reducing them to one sheet. Reference numeral 5043 denotes a continuous shooting key which is used to divide a copy area on the glass surface of the document table into two right and left sides and perform continuous copying in which two copies are automatically made (page continuous shooting, double-sided rapid shooting). Reference numeral 5044 denotes a double-sided key which is used to output both sides (single-sided double-sided, page continuous double-sided, double-sided double-sided). Reference numeral 5045 denotes a multiplex key, which is used when multiplexing is desired (multiplex, page continuous multiplex). 5
Reference numeral 046 denotes a memory key which is used when a mode using a memory is desired (memory combining, area combining, watermark combining).

Reference numeral 5047 denotes a projector key which is used when using the projector. Reference numeral 5048 denotes a printer key, which is used when setting for a printer. Reference numeral 5050 denotes a document mixed key, which is used when a document size is mixed when copying using the feeder. Reference numeral 5051 denotes a mode memory key, which is used when registering a copy mode set for copy and calling the registered copy mode. Reference numeral 5052 denotes a liquid crystal display with a touch panel, which displays the state of the apparatus, the number of copies, the copy magnification, and the copy paper size, informs the operator of the setting state of the copy mode, and according to the present invention, the platen glass at the time of moving reading. If the presence of garbage is recognized above,
Displays a message prompting cleaning.

Next, a schematic configuration of the image reading apparatus will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes a main body of an image reading apparatus, which has a reading position A formed on the upper surface glass thereof, and has a built-in scanning optical system B constituting reading means. The scanning optical system B includes a light source 2 for irradiating the original with light, folding mirrors 3a, 3b and 3c for reflecting light reflected from the original surface, an imaging lens 4 for imaging the reflected light, and an image. An image sensor 5 for photoelectrically converting the reflected light is provided. The light source 2 and the mirrors 3a, 3b, 3c are configured to be movable at a speed ratio of 1: 1/2.

An ADF 30 serving as a document feeding means is mounted on the upper surface of the image reading apparatus, and automatically feeds a document to a reading position A. As a document reading method using the ADF 30, as described above, the document is fixed at the reading position and the image is read by driving the 1: 1/2 optical system, or the 1: 1/2 optical system is fixed. There is a method of reading while transporting the original in the state.

Hereinafter, the configuration of the ADF 30 will be described. Here, a method of reading a document while transporting the document with the 1: 1/2 optical system fixed will be described. Reference numeral 6 denotes a document feed tray for stacking the documents P in a feedable manner, and the document 1001 is placed on the document feed tray 6 with the image surface facing upward. Reference numeral 7 denotes a document detection flag. When the document 1001 is inserted along the document feed tray 6, the document detection flag 7 rotates. As a result, a document detection sensor (not shown) is turned on to switch to the ADF mode, and the scanning optical system including the light source and the folding mirror (not shown) is moved to the reading position A and fixed, and enters a standby state.

Reference numeral 8 denotes a feeding roller, which is rotatably supported about a feeding roller shaft 9 and feeds the original 1001 inserted along the original feeding tray 6. Reference numeral 31 denotes a separation roller, which is rotatably supported about the separation roller shaft 11 and separates and conveys the fed document 1001. The separation roller shaft 11 is rotatably supported by the ADF 30. The feed roller shaft 9 is rotatably supported at both ends in the vicinity of a support hand 16, and the support hand 16 is connected to be fixed to the separation roller shaft 11. Therefore,
The support hand 16 is configured to rotate integrally about the separation roller shaft 11 while holding the feed roller shaft 9. Reference numeral 32 denotes a separation piece which is in pressure contact with the separation roller 31 and separates and transports the original 1001 fed one by one from the uppermost surface by the cooperation of the separation roller 31 and the separation piece 32.

Reference numerals 33a and 33b denote transport roller pairs, which transport the separated and transported original 1001 to the reading position A while inverting the original so that the image surface faces down. Then, the document 1001 whose image has been read by the above-described scanning optical system B is conveyed by the discharge roller pairs 34a and 34b and discharged onto the discharge tray 35. Document 1 in document feed tray 6
001 remains, that is, the document detection flag 7 is pressed by the weight of the document 1001 and the document detection sensor
In the case of the N state, the above operation is repeated until the document 1001 is removed from the document feeding tray 6.

When dust adheres to the glass at the reading position A, an unnecessary linear image signal is generated irrespective of the original image fed above. Here, FIG.
Is a diagram showing the influence of dust, and the image is read in the direction of the sensor array a (hereinafter referred to as the main scanning direction) for each line. Since the original is fed at a constant speed, the original is sequentially read (in the sub-scanning direction) as n lines, n + 1 lines, and n + 2 lines. Therefore, when dust is read in black, a position corresponding to almost the same sensor pixel in the main scanning direction as indicated by X in the figure is read as black regardless of the image. As a result, it is read as a black straight line perpendicular to the main scanning direction.

Next, the dust recognition unit 10 which is a feature of the present invention.
02 will be described with reference to FIGS. In FIG.
The image signal input to the dust recognition unit 1002 is first binarized by the simple binarization unit 108. FIG. 6A shows an image signal near dust X input from the light density conversion unit 105, and FIG. 6B shows a signal obtained by emphasizing the image signal in the main scanning direction. FIG. 6 shows the result of binarization using the threshold value K1.
The case where the image signal is darker than the threshold value is represented by "B" in FIG.
Thus, as a result of binarization of the n-th line, five B pixels are obtained as shown in FIG. 6D. Similarly, by sequentially processing the n + 1 and n + 2 lines, FIG.
(F) is obtained.

Here, the binarization result "B" includes a signal based on the normal image information on the original. However, if the B pixel due to the dust does not move, the B pixel is always the same on all the reading lines. B pixels are obtained at pixel positions in the scanning direction. Therefore, the binarization result is integrated by the histogram integration unit 109 for each pixel position in the main scanning over one page. FIG.
Indicates the integrated value of B pixels for about 5000 lines in the sub-scan for each pixel position for 7275 pixels in the main scan. In particular, the area near the garbage is enlarged.

In FIG. 7, the dust-affected portion X indicates that its integrated value has exceeded the threshold value K2, and has been detected as a B pixel on almost all lines. In this case, the histogram integrating unit is configured by an 8K ^* 13-bit RAM, and adds the integrated value of the pixel position corresponding to the detected B pixel by one each time each line is read. The threshold value is usually set to about 90% of the number of sub-scan lines to be sampled. By the threshold processing of the histogram, the pixel position GS where the influence of dust starts and the end pixel position GE are obtained for each read page. Although the generation of a plurality of dusts can be detected from the histogram, the description is omitted here.

As a result of the applicant's research, dust is usually gradually accumulated on the glass, and as a result, if the dust grows to such an extent as to affect the image signal, it is difficult to remove the dust by the degree of rubbing caused by feeding the original. . Therefore, the position of the dust hardly moves while reading several originals. In addition, when the document has image information such as ruled lines similar to the dust X shown in FIG. 5, it is often read with an inclination of about several tens of pixels. In most cases, this histogram can be separated from image information due to dust. However, it is not sufficiently accurate to determine the presence of dust from the histogram for one page. In the present invention, dust positions GS and GE obtained for each page over a plurality of pages are evaluated, and as a result, the presence of dust and its position are specified.

Next, an example of the case of identifying three pages will be described with reference to FIG. In the dust position determination unit in FIG. 1, the CPU 113 reads dust position data GS and GE obtained on each page, and determines the presence or absence of dust (step S301).
If there is dust, that is, if one or more sets of GS and GE are detected, S2 is stored in the internal register S3 (step S3).
02) Also, S1 is stored in the internal register S2 (step S303). Similarly, the address value of the currently detected GS is stored in the internal register S1 (step S30).
4). As a result, the GS value obtained when reading the page two pages before is stored in S3, and the GS value obtained one page before is read in S2.
The value and the currently obtained GS value are stored in S1. Similarly, the GE value obtained two pages before is stored in E3.
2 stores the GE value obtained one page before, and E1 stores the currently obtained GE value.

In step S306, the values of E3 and S3 are evaluated. If valid dust position data other than 0, ie, three pages before, is obtained and stored continuously, the flow branches to step S307. If the presence of dust cannot be detected in the page read at step S301, the flow branches to step S305, where the registers S3 and E3 are read.
And S2 and E2 are initialized to 0.

Now, steps S307 and S3
08, registers S1, S2, S3 and E
GS value and G for three pages stored in E1, E2, and E3
From the E value, max (S1, S2, S3), min (S
1, S2, S3), max (E1, E2, E3), mi
Find n (E1, E2, E3). Then, the presence of dust is recognized only when the variation of the GS value and the GE value for three pages is within two pixels. Therefore, the starting pixel position of the influence of dust is min (S1, S2, S3).
And the end pixel position is max (E1, E2, E3). This value is stored in a register as GSF and GEF, respectively (step S309).

If there is a variation of two or more pixels in the above evaluation, the process branches to step S310, and the G stored in the register is read.
Initialize SF and GEF to 0. As described above, dust can be recognized based on the presence of a pixel that has been binarized to black with a high cumulative frequency on the histogram within two pixels from the image signal for three pages.

When an image having a black area is continuously read over a wide range, there is a possibility that an erroneous determination is made. For this reason, in the dust determination in step S301, a restriction that "dust is present" is added only when the following equation is satisfied. Usually K3
Is preferably about 10. GE-GS <K3

Next, an image data correction unit 106 for correcting an image signal based on the obtained dust position data is provided by the image data correction unit 106 shown in FIG.
This will be described with reference to FIG. FIG. 9A is a diagram showing an algorithm for correcting an image signal, and shows a continuously input density signal sequence near the dust position. An example in which a GSF pixel and a GEF pixel are separated by 4 pixels is shown. Both pixel positions are obtained from the result of binarization with a fixed threshold. Therefore, pixels that are not actually affected by dust are considered to be before the GSF pixels. Therefore, in this embodiment, the image signal two pixels before the GSF pixel is determined to be the image signal closest to the dust position and not affected by the dust. The value of this image signal is used as the density signal of the subsequent four pixels. Similarly,
An image signal at a pixel position two pixels after the GEF pixel position is determined to be an image signal that is closest to the dust position and is not affected by dust, and is substituted for the density signal of the previous three pixels.

Specific examples are shown in FIGS. 9 (b), 9 (c) and 9 (d). (D) is a case where a black line is generated in a white background due to the influence of dust, and is an example in which the white line can be restored to a substantially white state. (C) is an example in which a black edge is on the right side and the influence of dust is superimposed on the edge. Although there is a possibility that the pixel may deviate from the original edge position by several pixels, almost the edge portion can be restored. (B) shows the case of a solid area close to black, which indicates that there is no adverse effect due to the restoration according to the present invention.

When the presence of dust is recognized, the display unit 5
At 052, the operator is prompted to clean the reading unit. In that case,
This operation of correcting the image data is performed until the dust is removed by cleaning by the operator or the dust is naturally removed by feeding a large number of documents. Similarly, when outputting image information to an external system using the external IF 121,
It is also possible to use the IF 121 to prompt the operator to clean the reading unit.

Although the above embodiment has been described with a black-and-white copying machine,
The present invention can be effectively applied to a color image reading device. That is, in the case of a color copying machine, the present invention may be implemented for each of the separated colors, or in the case of a device for reading and reading one point of a document at the same time, dust is detected by a single G signal and the same position is detected. The same effect can be obtained by modifying the image signals of other colors. The color-separated RG
When the present invention is implemented for each color on the B3 color signal, a pixel in which dust is detected in any color uses an adjacent pixel signal even if dust is not detected in another color. If the image signal is corrected, more accurate correction can be performed. That is
As in the case of the black-and-white system, as a result of color separation depending on the color of the dust, it is not possible to detect the presence of dust on the color signal that is determined to be "white", but it is not detected by other color signals. For example, an image signal that appears as a white line due to dust can be corrected.

Further, another embodiment of the image data correction will be described. FIG. 10 shows another embodiment of the image data correction unit 106. The example of FIG. 10 shows the density signal at the two pixel positions to be substituted, that is, “A” and G at the GSF-2 pixel position.
"B" at the EF-2 pixel position is used. The seven pixels X1, X2,. . . , X7 pixel positions, the density values “A” and “B” are internally divided and substituted according to the distances from the GSF-2 and GEF-2 pixel positions, respectively. Although the processing is more complicated than in the above-described embodiment, there is an advantage that the influence of dust can be corrected more smoothly. FIG. 10B shows a specific example in this case.

In the present embodiment, dust is recognized from the image signals for three pages. However, the same applies when the GS and GE values obtained from the histogram for one page are directly used as GSF and GEF to correct the image data. The effect of is obtained. Conversely, if dust is specified from data of three or more pages, a dust position with higher accuracy can be recognized. When the system is simple binary, that is, when the binarization unit 120 in FIG. 1 is only binary, the image data is corrected after this binarization unit 120 according to FIG. If it is corrected as data, the processing becomes easier.

In a normal document, information is rarely recorded from the end of the paper, and the influence of dust occurs from the recording start line. Therefore, the same effect can be obtained even if the sampling area for creating the histogram is not the entire area of one page but only a part of the head from the reading start line. Also, in creating the histogram, the capacity of the RAM to be used can be reduced to half by not counting the cumulative frequency for each pixel but reducing the resolution, for example, for every two pixels.

Here, each functional block and processing procedure shown in the above various embodiments may be constituted by hardware, or may be constituted by a CPU or an MPU, a ROM and an R.
It may be constituted by a microcomputer system composed of an AM or the like, and its operation may be realized according to a work program stored in a ROM or a RAM. The present invention also includes a software program for realizing the functions described above, which is provided to a RAM so as to realize the functions of the respective functional blocks, and which is executed by operating the functional blocks according to the programs. include.

In this case, the program itself of the software realizes the functions of the above-described embodiments, and the program itself and means for supplying the program to a computer, for example, a recording medium storing the program Constitute the present invention. As a storage medium for storing such a program, the above-described ROM or RAM
Besides, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, CD-I, CD-R, CD-RW, DVD, zi
p, a magnetic tape, a nonvolatile memory card, or the like can be used.

When the computer executes the supplied program, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software running on the computer. Needless to say, such a program is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with the above.

Further, after the supplied program is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the program is provided in the function expansion board or the function expansion unit based on the instruction of the program. It is needless to say that the present invention also includes a case where the CPU or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0060]

As described above, according to the present invention, a highly reliable image reading apparatus can be provided by removing unnecessary components superimposed on an image signal due to dust or the like generated on a glass platen. Can be provided.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view illustrating a structure of the image recording apparatus according to the embodiment of the present invention.

FIG. 3 is an external view of an operation unit according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a schematic configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating an influence of dust attached on glass at a reading position according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating an image signal and the like input to a dust recognition unit according to the embodiment of the present invention.

FIG. 7 is a diagram showing that an integrated value of an affected portion of dust exceeds a threshold value K2 and is detected as a B pixel on substantially all lines according to the embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation when identification is performed for three pages in the embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of image data for correcting an image signal based on dust position data according to the embodiment of the present invention.

FIG. 10 is a diagram showing another embodiment of the image data correction unit in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus main body 2 Light source 3a, 3b, 3c Folding mirror 4 Lens 5 Image sensor 11 Photoreceptor 12, 13 Developing unit 14, 15 Transfer receiving paper loading part 16 Transfer separation charger 17 Fixing part 18 Discharge roller 19 Direction flapper 103 A / D converter 104 Shading correction 105 Light density conversion circuit 106 Image data correction unit 107 Image editing unit 108 Binarization unit 110 Spatial filter unit 113 CPU circuit 115 RAM 117 Image recording unit

Continued on front page F term (reference) MP08 PP21 PP43 PP58 PQ19 PQ20 RR19 SS01 SS06 TT06 5L096 AA02 AA03 BA07 BA18 FA17 FA35 FA54 FA69 GA28 GA51 HA13 MA03

Claims (20)

[Claims] An image reading means for reading a document, an image signal processing means for processing an image signal obtained by the image reading means, and the presence of information other than the document image information based on the processing result of the image signal processing means. An image processing apparatus comprising: recognition means for recognizing; and image signal correction means for correcting an image signal obtained by the image reading means according to a recognition result of the recognition means. 2. The image processing apparatus according to claim 1, wherein the recognition unit recognizes the presence of dust superimposed on a document image. 3. The image processing apparatus according to claim 1, wherein the recognition unit recognizes a position of dust superimposed on a document image. 4. The image processing apparatus according to claim 1, wherein the image signal processing means performs a threshold process on the image signal. 5. The image processing apparatus according to claim 1, wherein the recognizing unit creates a histogram from the processing result of the image signal processing unit, and performs a threshold process on a cumulative frequency obtained from the histogram. 6. The image processing apparatus according to claim 1, wherein the recognition unit performs recognition on a plurality of documents, and recognizes the presence of information other than document image information based on a recognition result for each document. apparatus. 7. The image processing apparatus according to claim 1, wherein the image signal correction unit corrects information other than the document image information into document image information. 8. The image processing apparatus according to claim 1, further comprising an information output unit that outputs information corresponding to the recognition result to an operator according to the recognition result of the recognition unit. 9. The image signal correction unit for correcting any of the color-separated color image signals and an image signal of a plurality of colors obtained by the image reading unit according to a recognition result of the recognition unit. The image processing apparatus according to claim 1, further comprising: 10. An image reading step of reading an original,
An image signal processing step of processing the image signal obtained in the image reading step; a recognition step of recognizing the presence of information other than the document image information from the processing result of the image signal processing step; and a recognition result of the recognition step. An image signal correcting step of correcting the image signal obtained in the image reading step in response to the image signal. 11. The image processing method according to claim 10, wherein in the recognition step, the presence of dust superimposed on the document image is recognized. 12. The image processing method according to claim 10, wherein in the recognition step, a position of dust superimposed on the document image is recognized. 13. The image processing method according to claim 10, wherein the image signal is subjected to threshold processing in the image signal processing step. 14. The image processing method according to claim 10, wherein in the recognition step, a histogram is created from the processing result of the image signal processing step, and a cumulative frequency obtained from the histogram is subjected to threshold processing. 15. The image processing apparatus according to claim 10, wherein the recognition in the recognition step is performed on a plurality of documents, and the presence of information other than the document image information is recognized based on the recognition result for each document. Method. 16. The image processing method according to claim 10, wherein in the image signal correcting step, information other than the document image information is corrected into document image information. 17. The image processing method according to claim 10, further comprising an information output step of outputting information corresponding to the recognition result to an operator according to the recognition result of the recognition step. 18. The image signal correction for correcting any one of the color-separated color image signals, and correcting the image signals of a plurality of colors obtained in the image reading step according to the recognition result of the recognition step. The image processing method according to claim 10, further comprising the steps of: 19. A computer-readable storage medium storing a program for causing a computer to function as each of the means according to claim 1. Description: 20. A computer-readable storage medium storing a program for executing the processing procedure of the method according to claim 10. Description: