JP2004104587A - Image processing system and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relieve and avoid a defective image caused by dust and a stain which occur at the time of skimming through images. <P>SOLUTION: The presence/no presence of a black pixel is detected at the reading position of a document feeder at any of prescribed timing between sheets of paper when the power is supplied and when a job is finished. When the black pixel is recognized, warning is displayed and a filter for filtering processing is changed. When a black pixel is detected at all of a plurality of movable skimming through reading positions, the occurrences of a black stripe and of a defective image are prevented by setting the reading position at an initial position and changing the filter for filtering processing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing system and a control program for reading an original while transporting the original.
[0002]
[Prior art]
In a copier equipped with a document feeder, when a plurality of originals are set, automatically conveyed one by one, and the reading position is fixed and the image reading is performed. The pixel corresponding to that position is always dust reading data, and is a black streak extending in the sub-scanning direction to form defective image data. For example, if this image data is output by a printer without correction, a black line not found in the original is formed, which is very unsightly. At this time, it is ideal to physically remove dust causing the problem, but in many cases, it is impossible to perform the copying operation at a high speed or after a large amount of copying is started. In addition, small dirt that cannot be perceived by the naked eye can greatly affect the image, and there is a limit in expecting a user to completely remove dust. Therefore, it is necessary to detect the presence or absence of dust that may form a black line that does not exist in the original at the time of moving reading, and to specify the position of the dust. To cope with such a problem, Japanese Patent Application Laid-Open No. 2000-196814 detects in advance the occurrence of an abnormal image due to dust (dust), dirt, flaws, and the like on the upper and lower contact glasses in the document reading apparatus, and avoids the occurrence. An image reading system that reads a document at a reading position has been proposed.
[0003]
[Problems to be solved by the invention]
However, in recent years, the resolution of the image reading device has been increased, and along with the improvement of the image reproducibility of the image forming device, considerably fine dust and dirt on the image reading unit are generated as black stripes in the printed out image. Has become. Specifically, even a foreign matter of about 25 μm may be generated as a black streak image.
[0004]
However, if the sub-scanning accuracy error when the image reading unit returns to the reading position from another position is, for example, about 43 μm, dust of about 25 μm can be detected if the error exists within the error of 43 μm. There may not be. In addition, the dust and dirt not only remain at the reading position but also move in many cases. Even when the dust or dirt is detected, the dust or dirt appears during document conveyance even if it is not detected, resulting in a black streak image. Sometimes it happens. Even if such small dust and dirt affect the read image, the dust and dirt may be affected by the positional relationship between the pixels of the CCD and the dust, a change in the light amount of the document illumination lamp, a variation in light distribution, and the like. Therefore, there is a problem that it is difficult to stably detect the image, and it is inevitable to output a defective image such as a black stripe or a white stripe.
[0005]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problem, and an image processing system according to claim 1 reads a document feeder that automatically conveys a document and the document conveyed by the document feeder. A reading unit that converts and outputs the image data, a dust / flaw detecting unit that detects presence / absence of dust, scratches, or dirt at a reading position of the reading unit; And control means for changing a filtering process on the image data output from the reading means.
[0006]
The control program according to claim 10, further comprising: a document feeder that automatically conveys the document; and a reading unit that reads the document conveyed by the document feeder, converts the document into image data, and outputs the image data. A control program for controlling a processing system, wherein a dust / flaw detection step of detecting presence / absence of dust / flaw / stain at the reading position of the reading unit; and And a filtering process changing step of changing a filtering process on the image data output from the reading unit.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, one embodiment of the present invention will be described.
[0008]
FIG. 1 is a schematic view of a system according to an embodiment of the present invention.
[0009]
The scanner 11, which is an image input device, illuminates an image on paper serving as a document, and scans a CCD line sensor (not shown) to convert the image into raster image data into an electric signal. The manuscript paper is set on the tray 18 of the manuscript feeder 17, and when the apparatus user gives an instruction to start reading from the operation unit 13, the controller CPU 23 gives an instruction to the scanner 11, and the feeder 17 feeds the manuscript paper one by one and feeds the manuscript image. Is performed.
[0010]
The printer 12 is a part that converts raster image data into an image on paper. The method is an electrophotographic method using a photosensitive drum or a photosensitive belt, and an image is directly printed on paper by discharging ink from a micro nozzle array. There is an ink jet system for printing, etc., but any system may be used. Activation of the printing operation is started by an instruction from the controller CPU 23. The printer 12 has a plurality of paper feed stages so that different paper sizes or different paper orientations can be selected, and has a paper cassette 15 corresponding thereto. The paper discharge tray 16 receives printed paper.
[0011]
FIG. 10 is a sectional view showing details of the scanner 11.
The ADF 50 automatically feeds the originals stacked on the original feed tray 60 onto the platen glass 51. At this time, a descending reading mode in which the stacked originals are fed onto the platen glass 51 in order from the bottom. , An ascending reading mode in which paper is fed from the top can be selected.
[0012]
A scanner unit 52 includes a document illumination lamp 53, scanning mirrors 54 to 56, and the like. The scanner unit 52 normally scans the original on the platen glass 51 by the original illumination lamp 53 by reciprocating in the horizontal direction, and reflects the reflected light from the original via the scanning mirrors 54 to 56 and the lens 57. Then, the light is incident on the CCD sensor 58 and photoelectrically converted.
[0013]
At the time of scanning reading, the originals stacked on the original feed tray 60 are automatically conveyed one by one onto the platen glass 51, but the scanner unit 52 is fixed to a predetermined position without moving, and is conveyed to the conveying belt 59. The original conveyed is illuminated by an illumination lamp 53, and reflected light is incident on a mirror 54. The document conveyed by the conveyance belt 59 is discharged onto a document discharge tray 61. Further, instead of the transport belt, a transport roller may be used for transporting the document.
[0014]
FIG. 2 shows an image controller (Image Controller).
[0015]
The controller unit 20 is a controller for connecting to the scanner 11 and the printer 12 and connecting to the LAN 36 to input and output image information and device information. The CPU 23 is a controller that controls the entire system. The RAM 24 is a system work memory for the operation of the CPU 23, and is also an image memory for temporarily storing image data. The ROM 27 is a boot ROM and stores a system boot program. The HDD 28 is a hard disk drive that stores system software, image data, and function information of the image output device. The operation unit I / F 25 is an operation unit (UI) 13 and an interface unit, and outputs image data to be displayed on the operation screen 14 to the operation unit 13. Further, it plays a role of transmitting information input by the system user from the operation unit 13 to the CPU 23. The network 26 is connected to the LAN 36 and inputs and outputs information. The Calendar IC 37 manages time. The above devices are arranged on the system bus 21. The image bus I / F 29 is a bus bridge that connects the system bus 21 and the image bus 22 that transfers image data at high speed, and converts a data structure. The image bus 22 is constituted by a high-speed bus such as a PCI bus. The following devices are arranged on the image bus 22. A raster image processor (RIP) 30 develops a PDL (Page Description Language) code into a bitmap image. The device I / F unit 31 connects the controller 20 to the scanner 11 or the printer 12, which is an image input / output device, and performs synchronous / asynchronous conversion of image data. The scanner image processing unit 32 performs correction, processing, and editing on input image data. The printer image processing unit 33 performs printer correction, resolution conversion, and the like on the print output image data. The dust detection unit 34 detects whether dust is attached to the reading portion during the flow reading, and performs a process of detecting a dust attachment position.
[0016]
FIG. 3 shows the scanner image processing unit 32. The image bus I / F controller 301 is connected to the image bus 22, controls the bus access sequence of the image bus I / F controller 301, and generates control and timing of each device in the scanner image processing unit 32. Filter processing section 302 performs a convolution operation using a spatial filter. The editing unit 303 recognizes, for example, a closed area surrounded by the marker pen from the input image data, and performs image processing such as shadowing, shading, and negative / positive inversion on the image data in the closed area. . When changing the resolution of the read image, the scaling unit 304 performs an interpolation operation in the main scanning direction of the raster image to perform enlargement and reduction. The magnification in the sub-scanning direction is changed, for example, by changing the scanning speed of an image reading line sensor (not shown). The table 305 is stored in the ROM 27 and performs table conversion for converting image data, which is read luminance data, into density data. The binarization 306 binarizes multi-value grayscale image data by error diffusion processing or screen processing.
[0017]
Then, the processed image data is transferred to the image bus via the image bus controller 301 again.
[0018]
FIG. 4 shows the printer image processing unit 33. The image bus I / F controller 401 is connected to the image bus 22, controls the bus access sequence, and controls and timings of each device in the printer image processing unit 33. The resolution conversion unit 402 performs resolution conversion for converting image data coming from the LAN 36 to the resolution of the printer 12. The smoothing processing unit 403 performs a process of smoothing jaggies (roughness of an image appearing at a black-and-white boundary such as an oblique line) of the image data after resolution conversion.
[0019]
(First embodiment)
The dust detection operation at the reading position will be described with reference to the flowcharts of FIGS.
[0020]
The originals stacked on the original feed tray 60 are read by drift reading, and after all the originals have been read, the dust detection operation is started. The dust detection flag is in an off state.
[0021]
First, in step (hereinafter, referred to as S) 101, the transport belt 59 is moved at a predetermined speed.
[0022]
Here, the transport belt is used for transporting the original, but when a transport roller is used, the transport roller may be rotated.
[0023]
In S102, the illumination lamp 53 is turned on.
[0024]
In step S103, the image on the surface of the transport belt 59 is read a predetermined number of times through the platen glass 51 in a state where there is no original after all the originals have been read.
[0025]
Here, the image on the surface of the transport belt 59 is read through the platen glass 51 in a state where there is no document to be read after reading of all documents loaded on the document feeder 17 is completed at a predetermined timing. In the read operation of a plurality of originals, the operation may be performed before the next original is conveyed to the reading position after the original of the previous page is read and before the start of reading the next page.
[0026]
Further, although the image on the surface of the transport belt is read through the platen glass 51, when a transport roller is used, the image on the surface of the rotating transport roller may be read.
[0027]
In S104, the predetermined number of luminance signals read in S103 are averaged. At this time, if there is no dust or dirt on the platen glass 51, the read luminance signal is as shown in FIG. When dust or dirt is attached to the surface of the conveyor belt 59, the conveyor belt 59 is moving, so that the signal on the platen glass 51 does not become a continuous signal indicating a black stripe. , Can be distinguished from dirt. In step S105, the dust detection unit 34 compares a luminance signal of a pixel corresponding to a portion where dust has adhered to the image data read at the reading position with a detection threshold previously set and recorded in the ROM 27. It is determined that there is dust or dirt at the main scanning position where the luminance signal is detected (yes). Then, the process proceeds to S106.
[0028]
FIG. 6 shows a luminance signal when there is dust or dirt at the reading position on the platen glass 51. If the detection threshold value is not less than the detection threshold value even in the state where there is dust or dirt, and if the original is read in this state, the image is processed by the image control unit 20 to perform predetermined image processing. The luminance signal level is set so that the image is not affected even when the image is output in step S12.
[0029]
On the other hand, if no luminance signal is below the detection threshold (no), the dust detection operation ends. Then, the process proceeds to S108.
[0030]
In S106, if there is image data that is lower than the detection threshold in S105, and it is determined that there is dust (Yes), the scanner unit 52 is moved by a predetermined distance. As a result, the reading position is changed, and dust adhering on the platen is avoided.
[0031]
In S107, a dust detection flag for determining that there is dust is turned ON.
[0032]
In S108, it is checked whether the dust detection flag in S106 is ON. If it is On, the process proceeds to S109, and if it is off, the dust detection operation ends there.
[0033]
In step S109, for example, a warning as shown in FIG. 9 is displayed on a display device (not shown) in the operation unit 13 to notify the operator of cleaning of dust attached to the platen glass.
[0034]
In S111, the reading position is changed in S106 to avoid the reading of dust, and further, the filter constant of the filter processing unit 302 of the scanner image processing unit 32 is changed. Makes abnormal images inconspicuous.
[0035]
This is the end of the dust detection operation.
[0036]
Dust and dust that cause black streaks are easy to move, and stable detection is also possible due to the positional relationship between CCD pixels and dust, changes in the amount of light from the document illumination lamp, and variations in light distribution. Therefore, if dust is detected, if the dust is detected, it is possible to change the filter constant. In addition, it is possible to prevent the occurrence of black streaks that occur when dust moves during document conveyance or when dust newly appears.
[0037]
As an example, FIGS. 7 and 8 show examples of filter constants in the character mode of a copying machine. FIG. 7 shows a filter constant of 7 pixels × 7 pixels in the normal character mode. When the dust detection unit 34 determines that there is dust, the filter constant in the character mode is changed as shown in FIG. Specifically, in this filter, dust is made inconspicuous by relaxing the edge emphasis, so that any filter that can perform a smoothing process such as a low-pass filter may be used.
[0038]
(Second embodiment)
Next, a description will be given of an embodiment in which a plurality of fixed positions of the scanner unit at the time of moving reading can be set, with reference to the flowcharts of FIGS.
[0039]
The reading position P of the scanner unit 52 at the time of the flow reading can be set to P1, P2,. The originals stacked on the original feed tray 60 are read by drift reading, and after all the originals have been read, the dust detection operation is started.
[0040]
First, in S201, the position P is set to N = 1st, and is set as an initial position P1. Next, the processing in S202 to S206 is the same as that in S102 to S104 in the first embodiment, and a description thereof will be omitted. If there is a luminance signal lower than the detection threshold in the image read at the predetermined timing in S207 and it is determined that there is dust or dirt (yes), the process proceeds to S208. If it is determined that there is no dust (no), the reading position is set to P1, and the dust detection operation ends.
[0041]
On the other hand, if there is no luminance signal lower than the detection threshold (no), the dust detection operation ends, and reading is performed at that position.
[0042]
In S208, it is checked whether the reading position P of the scanner unit 52 has reached the last n-th position. If it is not the n-th (no), the process proceeds to S209. If it is the nth (yes), the process proceeds to S211. If the reading position of the scanner unit 52 is not the last n-th position in S208, the scanner unit 52 is moved by a predetermined amount in a predetermined direction in S209. Then, in S210, the process advances to PN + 1, which has been moved by a predetermined amount from the reading position PN, and returns to S204. Then, the processing of S204 to S206 is performed. If dust is not detected in S207 (no), the reading position is set to PN + 1, and the dust detection operation ends.
[0043]
If the reading position of the scanner unit 52 has reached the last nth position in S208, that is, if it is determined that there is dust at any position from P1 to Pn, the reading position is returned to P1 in S211. Next, in S212, for example, a warning as shown in FIG. Then, in S213, the filter processing unit 302 changes the filter constant. Thus, the dust detection operation is completed, the filter constant is changed, and the original reading operation is performed.
[0044]
(Third embodiment)
The third embodiment will be described with reference to the flowcharts of FIGS. Steps S301 to S313 are the same as those in the second embodiment, and a description thereof will be omitted.
[0045]
If there is a position where dust is not detected, the document reading operation is performed at that position in S314. If dust is detected at any one of the reading positions in P1 to Pn-1, the process proceeds to S315. Use to change the filter constant of the filter processing unit. This is because dust is easy to move and may appear during document conveyance. Also, since it is difficult to obtain a stable viewpoint due to the positional relationship between the pixels of the CCD and dust, changes in the amount of light of the document illumination lamp, and variations in the light distribution, if dust is detected even once, the following Even if dust is not detected at the reading position, the filter constant is further changed by the filter processing unit to prevent the occurrence of black streaks.
[0046]
(Fourth embodiment)
In the first, second and third embodiments, the system automatically detects dust, moves the reading position of the scanner unit, and changes the filter constant. However, the user determines the presence or absence of dust at the reading position from the printout result. However, the same effect can be obtained by moving the scanner unit or changing the filter constant by the user from the operation unit. In this case, it is also possible to independently move the scanner unit and change the filter constant.
[0047]
The change of the filter constant may be reset when the user cleans the platen glass while watching the warning display, or may be reset when the pressure plate is opened and closed.
[0048]
【The invention's effect】
As described above, according to the present invention, when dust, scratches, or dirt is detected, it is possible to detect the presence of dust, scratches, or the like at the reading position by changing the filtering process. In the case where there is no dust, when dust moves during document conveyance, or when dust newly appears during document conveyance, output of a defective image such as a black stripe can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic view of a copier equipped with a document feeder according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an image control unit (Image Controller).
FIG. 3 is a diagram illustrating a scanner image processing unit.
FIG. 4 is a diagram illustrating a printer image processing unit.
FIG. 5 is a diagram showing a read value when there is no dust.
FIG. 6 is a diagram showing a read value when there is dust.
FIG. 7 is an example of an initial character mode filter constant.
FIG. 8 is an example of a character mode filter constant after dust detection according to the embodiment of the present invention.
FIG. 9 is an example of a warning screen display according to the embodiment of the present invention.
FIG. 10 is a diagram illustrating a cross-sectional view of a scanner.
FIG. 11 is a flowchart showing a dust detection operation according to the first embodiment of the present invention.
FIG. 12 is a flowchart illustrating a dust detection operation according to the second embodiment of the present invention.
FIG. 13 is a flowchart illustrating a dust detection operation according to the third embodiment of the present invention.
[Explanation of symbols]
11 scanner 12 printer 13 operation unit 17 feeder 23 CPU
32 scanner image processing unit 33 printer image processing unit 34 dust detection unit 51 platen glass 52 scanner unit 53 document illumination lamps 54 to 56 mirror 57 lens 58 CCD
59 Conveyor belt 302 Filter processor

Claims (17)

A document feeder that automatically transports documents,
Reading means for reading the original conveyed by the document feeder, converting the original into image data, and outputting the image data;
Dust / flaw detection means for detecting presence / absence of dust, flaws or dirt at the reading position of the reading means,
An image processing system comprising: a control unit configured to change a filtering process on the image data output from the reading unit when the dust / flaw detection unit detects dust, flaws, or dirt. The image processing system according to claim 1, further comprising a warning unit that warns when dust, scratches, or dirt is detected by the dust scratch detection unit. 3. The image processing system according to claim 1, wherein the dust / flaw detection unit detects dust or flaws using image data read by the reading unit at a predetermined timing. 4. The image processing system according to claim 3, wherein the predetermined timing is a period from completion of reading of the document to start of reading of the next document. 4. The image processing system according to claim 3, wherein the predetermined timing is a state in which a document is not placed on the document feeder after reading of all documents placed on the document feeder is completed. A reading position changing unit that changes a reading position of the reading unit in accordance with a detection output of the dust flaw detecting unit; and dust is provided in at least one of a plurality of reading positions of the reading unit that can be changed by the reading position changing unit. The image processing system according to any one of claims 1 to 5, wherein the control unit changes the filtering process when it is detected that a flaw is present. When the dust / flaw detection means detects dust or flaws in all of the plurality of reading positions, the control means sets the reading position of the reading means to an initial position and changes the filtering process. The image processing system according to claim 6, wherein The image processing system according to claim 6, further comprising an operation unit configured to change the reading position and / or change the filtering process. The image processing system according to claim 1, further comprising an operation unit configured to change the filter processing. A document feeder that automatically conveys a document, and a reading unit that reads the document conveyed by the document feeder, converts the document into image data, and outputs the image data.
A control program for controlling an image processing system having
A dust / flaw detection step of detecting presence / absence of dust, flaws, or dirt at the reading position of the reading unit;
A filter process changing step of changing a filter process for the image data output from the reading unit when dust, a scratch or dirt is detected in the dust scratch detection step;
A control program characterized by having: The control program according to claim 10, further comprising a warning step of warning when dust, a scratch, or dirt is detected in the dust scratch detection step. The image processing system has an operation unit, and in the dust scratch detection step, when dust, a scratch, or dirt is detected, accepts a user operation from the operation unit in the filter processing change step, and responds to the user operation. The control program according to claim 10, wherein the filter processing is changed. 12. The control program according to claim 10, wherein in the dust / flaw detection step, dust, flaws, or dirt is detected using image data read by the reading unit at a predetermined timing. 14. The control program according to claim 13, wherein the predetermined timing is between completion of reading of the document and starting of reading of the next document. 14. The control program according to claim 13, wherein the predetermined timing is a state in which a document is not placed on the document feeder after reading of all documents placed on the document feeder is completed. A reading position changing step of changing a reading position of the reading means in accordance with a detection output in the dust / flaw detecting means step, wherein at least one of a plurality of reading positions of the reading means changeable in the reading position changing step; The control program according to any one of claims 10 to 15, wherein the filter processing is changed when it is detected that dust, scratches, or dirt is present. In the dust / flaw detection step, when dust, flaws, or dirt is detected in all of the plurality of reading positions, the reading position of the reading unit is set to an initial position, and the filtering process is changed. 17. The control program according to claim 16, wherein

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