JP2005094482A - Digital image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital image reader by which the determination of stains such as dust can be accurately executed with image data obtained by reading a white reference plate for the shading correction in a current state and in the initial state with a scanning optical system. <P>SOLUTION: The white reference data in the initial state are obtained by reading the white reference plate 30 in the initial state with an exposure scanning optical system 12, and are stored in a nonvolatile memory in an MFP 1. The white reference data in a current state obtained by reading the white reference plate 30 in a current state with the exposure scanning optical system 12 and the white reference data in the initial state of the nonvolatile memory are outputted to a host as the determination data for the stains of the exposure scanning optical system 12 in an off-state of a shading correction processing part. Accordingly, a serviceman or the like can plainly determine the affects of the dust and the stain adhered on the scanning line of the white reference plate 30 from the output image data. The device state generates an abnormal image, and can be accurately grasped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital image reading apparatus, and more particularly, exposure scanning of an optical system that scans current white reference data obtained by reading a current white reference plate and initial white reference data stored in a nonvolatile memory in advance. The present invention relates to a digital image reading apparatus that outputs and accurately determines dirt due to dirt and paper dust adhering to a line.

  An electronic filing system that captures paper documents as electronic image data using a digital image reading device such as a black and white image scanner in order to increase the efficiency of document management in offices and the like. Needs are increasing.

  On the other hand, in a color image scanner equipped with an ADF (Auto Document Fieder), paper dust or the like is generated in the document passing path due to rubbing of the document during passing, and a large amount of paper is passed. When dust accumulates in the paper passing path, or when paper dust or the like fluctuates due to document conveyance or image reading device operation during paper passing, paper dust adheres to the scanning line and an abnormal image is generated. .

  When such paper dust or dust (hereinafter referred to as paper dust or the like) adheres to the reading scanning line, an abnormal image such as a black streak occurs in the read image read by the reading unit. It is not possible to confirm that paper dust or the like has adhered to the contact glass, and it will be recognized that paper dust or the like has adhered to the contact glass only after an abnormal image appears in the read image. .

  Therefore, conventionally, in image reading apparatuses such as scanners, facsimile apparatuses, and copying apparatuses, generally, when a predetermined number of sheets have been passed, a display that prompts the user to clean the passage path is performed. In addition, the occurrence of abnormal images due to paper dust or the like adhering to the scanning line is prevented.

  In addition, the present applicant has previously proposed an image reading device that detects abnormalities in adhesion of paper dust and the like based on white reference data when a white reference plate is read and notifies the user (patent) Reference 1).

  However, the frequency of paper dust generation is also affected by the usage environment such as paper quality / paper thickness and temperature / humidity, and it is not very appropriate to clean the paper passing route based on the number of paper passing, and the user does not pass through it. On the contrary, cleaning the paper path may cause dirt such as paper dust to adhere, and may cause new dirt on other parts. The user cannot disassemble and remove the paper dust that has entered inside.

  Therefore, although the service person performs cleaning at the time of regular maintenance, there is a problem that when the image quality deteriorates during the maintenance cycle, the user's impression on the image reading apparatus is deteriorated.

  When dirt such as paper dust enters the white reference data for shading correction, a streak-like abnormal image is likely to occur.

  Therefore, conventionally, when white reference data obtained by reading a white reference plate is stored in a memory, the level difference between the white reference data and the previous white reference data stored in the memory after reading the previous white reference plate is a predetermined value. Is within the range, the front white reference data stored in the memory is rewritten with the current white reference data, and the image data of the original is corrected based on the white reference data. If the level difference is equal to or greater than a predetermined value, an error is notified. In addition, there has been proposed an image signal correction apparatus that corrects image data of a document with front white reference data stored in a memory (see Patent Document 2).

  However, in this prior art, when the level difference between the current white reference data and the front white reference data is greater than or equal to a predetermined value, the shading correction is performed on the front white reference data, so that the predetermined value is gradually exceeded. When dust or the like adheres over time, such as when the dust adheres, it cannot be dealt with and needs to be improved.

  In addition, the applicant first determines that there is a pixel whose white reference data has changed by a predetermined amount or more, and determines that the pixel is dust or the like, and corrects the pixel of the white reference data with an adjacent pixel (patent) 3), pixel data correction means for correcting pixel data at the detected dust position, bright data correction means for correcting read data of the white reference plate used for shading correction, and pixel data at the detected dust position. An image processing apparatus comprising: control means for setting whether to enable or disable correction processing by the pixel data correction means in accordance with a preset condition such as a pixel width (see Patent Document 4) is suggesting.

  Further, the applicant first compares the target pixel of the plurality of white data acquired by reading each of the plurality of white reference plates and the surrounding pixels, and finds a singular point where the values of the target pixel and the surrounding pixels are greatly different. When the singular point positions coincide with each other in the reference values of the plurality of white data, the positions are stored, and the read original image data is referred to the surrounding pixels at the singular point positions, A shading correction processing device that replaces values of peripheral pixels has been proposed (see Patent Document 5).

JP 2001-157053 A Japanese Patent Publication No.8-15309 JP 2001-86333 A JP 2000-115488 A JP-A-11-261816

  However, in such a conventional technique, the white reference data is corrected with the adjacent pixel as it is as the pixel at the dust position, or the document pixel at the dust position is corrected by calculating data from the surrounding pixels by interpolation or the like, Because it prevents the occurrence of streaky abnormal images, it depends on the state of dirt such as paper dust (size and density change amount), and there is a limit to the ability to deal with dirt such as paper dust, improving image quality. Above, there was a need for improvement.

  Accordingly, the invention according to claim 1 is a scanning optical system that irradiates a conveyed document with light at a reading position and reads an image of the document with the reflected light, and a predetermined white reference plate at a predetermined time before reading the document. The shading correction unit stores the image data when the white reference plate is read as read white reference data, and the image data obtained when the original is read based on the stored white reference data is corrected by shading. The initial state white reference plate read by the scanning optical system was stored in the nonvolatile memory, and the current white reference plate was read by the scanning optical system with the shading correction means turned off. By outputting the current white reference data and the initial white reference data of the non-volatile memory as dirt judgment data for the scanning optical system, a service person or the like The output image data makes it possible to determine the effects of dust and dirt adhering to the scanning line of the white reference plate at a glance, so that the state of the device that generates an abnormal image can be accurately grasped, and maintenance by service personnel ( Users who have improved the accuracy of the cleaning of the paper passage route only within the range that can be reached from the outside of the device / if necessary inside the device, preventing unnecessary maintenance time from being lengthened and improper maintenance. An object of the present invention is to provide a digital image reading apparatus that improves the usability and the maintenance efficiency of service personnel.

  The invention described in claim 2 is provided with a reduction processing means for reducing the image read by the scanning optical system, and the initial state white reference data obtained by reading the white reference plate in the initial state by the scanning optical system is reduced by the reduction processing means. The current white reference data stored in the non-volatile memory and the current white reference plate read by the scanning optical system with the shading correction means off are reduced by the reduction processing means, and the reduced current white reference data And the reduced initial state white reference data of the non-volatile memory is output as dirt judgment data of the scanning optical system, thereby reducing the efficiency of the reduction processing means generally mounted on the digital image reader for image processing. The initial state white reference data is reduced and stored in the non-volatile memory to reduce the size of the non-volatile memory and prevent unnecessary maintenance time from being extended at low cost. And to provide a digital image reading apparatus to improve the usability and service person of the maintenance of the efficiency of the user by fine improper maintenance.

  According to a third aspect of the present invention, an image of an initial white reference plate and an existing white reference plate is displayed on a display means on the basis of the initial white reference data and the current white reference data. A digital image reading device that makes it possible to confirm the influence of dust and dirt adhering to document scanning by itself and to reduce the additional work by outputting it as image data to the outside of the device, thereby making maintenance work more efficient The purpose is to provide.

  According to a first aspect of the present invention, there is provided a digital image reading apparatus that irradiates a conveyed original with light at a reading position and reads an image of the original with reflected light, and a predetermined time at a predetermined time before the original is read. The white reference plate is read, the image data when the white reference plate is read is stored as read white reference data, and the image data when the original is read is corrected based on the stored white reference data A non-volatile memory that stores initial state white reference data obtained by reading the white reference plate in an initial state with the scanning optical system, and the shading correction unit is turned off. In this state, the current white reference data obtained by reading the current white reference plate with the scanning optical system and the initial state white reference data of the nonvolatile memory. And by outputting the decision data of contamination of the scanning optical system, it has achieved the above objects.

  In this case, for example, the digital image reading apparatus includes a reduction processing unit that reduces an image read by the scanning optical system, and the white reference plate in the initial state is used as the scanning optical device. The initial state white reference data read by the system is reduced by the reduction processing means and stored in the nonvolatile memory, and the current white reference plate is read by the scanning optical system with the shading correction means turned off. The current white reference data is reduced by the reduction processing means, and the reduced current white reference data and the reduced initial state white reference data of the nonvolatile memory are used as dirt determination data for the scanning optical system. May be output.

  Further, for example, as described in claim 4, the digital image reading apparatus includes a predetermined display unit, and based on the initial state white reference data and the current white reference data, an initial state white reference plate And an image of the current white reference plate may be displayed on the display means.

  According to the digital image reading apparatus of the first aspect of the present invention, the scanning optical system that irradiates the conveyed original with light at the reading position and reads the image of the original with the reflected light at a predetermined time before reading the original. When the predetermined white reference plate is read, the shading correction means stores the image data when the white reference plate is read as read white reference data, and reads the document based on the stored white reference data When correcting shading of image data, the initial white reference data read by the scanning optical system is stored in the non-volatile memory, and the current white reference plate is scanned with the shading correction means off. The current white reference data read by the optical system and the initial state white reference data of the nonvolatile memory are output as dirt determination data for the scanning optical system. It is possible to identify the influence of dust and dirt adhering to the scanning line of the white reference plate from the output image data at a glance, and to accurately grasp the state of the apparatus that generates the abnormal image. It is possible to improve the accuracy of performing maintenance (cleaning of the paper passage route) by service personnel only within the range that can be reached from the outside of the device / as needed inside the device, and lengthen unnecessary maintenance time. In addition to preventing this, it is possible to improve the usability of the user and the maintenance efficiency of the service person due to inappropriate maintenance.

  According to the digital image reading apparatus of the second aspect of the invention, the reduction processing means for reducing the image read by the scanning optical system is provided, and the initial state white reference data obtained by reading the white reference plate in the initial state by the scanning optical system is provided. Reduced by the reduction processing means and stored in the non-volatile memory, the current white reference plate read by the scanning optical system with the shading correction means turned off is reduced by the reduction processing means, Since the reduced current white reference data and the reduced initial state white reference data in the nonvolatile memory are output as dirt determination data for the scanning optical system, a digital image reader is generally mounted for image processing. By efficiently utilizing the reduction processing means, the initial state white reference data can be reduced and stored in the non-volatile memory to reduce the size of the non-volatile memory, which is unnecessary at low cost. It is possible to prevent the lengthening of the maintenance time, it is possible to improve the usability and service person of the maintenance of the efficiency of the user due to improper maintenance.

  According to the digital image reading apparatus of the present invention, the images of the white reference plate in the initial state and the current white reference plate are displayed on the display unit based on the initial state white reference data and the current white reference data. Therefore, it is possible to confirm the influence of dust and dirt adhering to the original scanning with the digital image reading apparatus alone, and to reduce the additional work by outputting the image data to the outside of the apparatus, thereby further improving the efficiency of the maintenance work. be able to.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The scope of the present invention limits this invention especially in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  1 to 5 are diagrams showing an embodiment of a digital image reading apparatus of the present invention. FIG. 1 is a schematic front view of a digital image reading apparatus 1 to which an embodiment of the digital image reading apparatus of the present invention is applied. It is a block diagram.

  In FIG. 1, a digital image reading apparatus 1 is provided with a platen glass 3 on an upper part of a main body casing 2, and an ADF (automatic document feeder) 4 is attached to the upper part of the platen glass 3 so as to be opened and closed. ing. The ADF 4 also has a function of a thick plate that presses the document set on the document table glass 3 so as to be in close contact with the document table glass 3.

  Inside the main body housing 2 are an illumination lamp 5 and a first mirror 6 mounted on a first traveling body (not shown), a second mirror 7 and a third mirror 8 mounted on a second traveling body (not shown), and a lens 9. An exposure scanning optical system (scanning optical system) 12 including a CCD (Charge Coupled Device) 10 and a traveling body motor 11 is disposed. The CCD (imaging device) 10 is attached to a substrate 13. In the exposure scanning optical system 12, the first traveling body and the second traveling body are moved in the horizontal direction (sub-scanning direction: a direction indicated by a double arrow A in FIG. 1) by the traveling body motor 11, and illumination on the first traveling body is performed. Light is emitted from the lamp 5 to the document placed on the platen glass 3, and the reflected light of the light reflected by the document is reflected by the first mirror 6 on the first traveling body toward the second traveling body. Then, the light incident from the first traveling body is sequentially reflected by the second mirror 7 and the third mirror 8 on the second traveling body, and is emitted toward the lens 9. The lens 9 collects and irradiates the light incident from the second traveling body on the CCD 10. The CCD 10 has a plurality of CCD elements arranged one-dimensionally as a plurality of photoelectric conversion elements. The CCD 10 photoelectrically converts incident light incident from the lens 9 and outputs analog image data (image signal).

  The ADF 4 includes a document tray 21, a pickup roller 22, a registration roller pair 23, a transport drum 24, a plurality of transport rollers 25, paper discharge roller pairs 26 and 27, a transport motor 28, a paper discharge tray 29, and the like.

  The ADF 4 feeds the originals stacked on the original tray 21 to the output roller pairs 26 and 27 through the reading position B by the pickup roller 22, the registration roller pair 23, the transfer drum 24 and the transfer roller 25, and the discharge tray 29. Drain up. When the original passes through the reading position B, the original is irradiated by the illumination lamp 5 that has been moved to the vicinity of the reading position B, and the reflected light is reflected by the first mirror 6, the second mirror 7 that is integrally formed, and the third mirror. Scanned by the mirror 8. Thereafter, the reflected light is focused by the lens 9 and irradiated to the CCD 10 for photoelectric conversion.

  The pickup roller 22 and the registration roller pair 23 are driven by a paper feed motor (not shown), and the transport drum 24, the transport roller 25, and the paper discharge roller pairs 26 and 27 are driven by the transport motor 28.

  A white reference plate 30 is installed in the vicinity of the reading position B. The white reference plate 30 reads a document having a uniform density due to variations in the illumination lamp 5 and uneven sensitivity for each pixel of the CCD 10. Despite this, it is used for shading correction of the phenomenon that the read data varies. The shading correction is performed using the volatile memory 45 (see FIG. 2). First, the white reference plate 30 is read for one line in the main scanning direction before scanning the document, and the read white reference data is stored in the volatile memory 45 as a white reference. Data is stored and divided by the corresponding stored white reference data for each pixel scanned from the original.

  As shown in FIG. 2, the digital image reading apparatus 1 has a block configuration, and includes a sensor 41, a shading correction processing unit 42, a scaling processing unit 43, a check processing unit 44, a volatile memory 45, a nonvolatile memory 46, An image processing unit 47, a memory controller 48, a memory 49, an I / F controller 50, and the like are provided. A host 100 such as a personal computer is connected to the I / F controller 50, and the host 100 includes display means. A CRT (Cathode Ray Tube) 101 is connected.

  The sensor 41 is composed of a line sensor using the CCD 10 and an A / D converter, reads an original with the CCD 10, and outputs an electrical signal of light and shade to the A / D converter. The A / D converter Is converted into an 8-bit digital signal and output, for example.

  A shading correction processing unit (shading correction means) 42 performs the above-mentioned shading correction for each scanning line, and performs variation correction caused by illumination unevenness and sensitivity unevenness for each pixel of the CCD 10.

  That is, as shown in FIG. 3, the shading correction processing unit 42 includes a white reference generation circuit 61, a shading correction calculation circuit 62, a selector 63, and the like, and the output image data from the sensor 41 is converted into the white reference generation circuit 61. Are input to the shading correction arithmetic circuit 62 and the selector 63. The output image data from the sensor 41 is a document having a uniform density due to unevenness in sensitivity for each pixel of the CCD 10 and illuminance distortion caused by the light quantity from the illumination lamp 5 being highest in the central portion on the scanning line. Despite reading, has variation and distortion. In order to correct this distortion, the white reference plate 30 having a uniform white surface is read, and the data output from the CCD 10 when the white reference plate 30 is read is generated as white reference data by the white reference generation circuit 61. And stored in the volatile memory 45. That is, for example, data indicating the variation and distortion in the main scanning direction as shown in FIG.

  The volatile memory 45 clears stored data when the power of the digital image reading apparatus 1 is turned off. Therefore, each time the document is scanned after the power of the digital image reading apparatus 1 is turned on. In addition, the data of the white reference plate 30 is read and stored in the volatile memory 45.

  Then, the shading correction processing unit 42 obtains white reference data corresponding to each pixel stored in the volatile memory 45 with respect to the image data obtained by reading the document sent from the sensor 41 during the normal document reading operation. Then, the variation and distortion are calculated and corrected by the shading correction calculation circuit 62, and output to the selector 63. Note that during the normal document reading operation, the white reference generation circuit 61 stops its operation.

  The selector 63 selects the white reference plate read image data from the sensor 41 during the white reference plate initial state capturing operation, and outputs it to the scaling unit 43. During the normal document reading operation, the selector 63 operates the shading correction calculation circuit 62. The data subjected to the shading correction is selected and output to the scaling processing unit 43. The selector 63 selects the white reference plate read image data from the sensor 41 and outputs it to the scaling processing unit 43 during the check operation of the white reference plate 30. During the white reference plate check operation, the white reference generation circuit 61 is stopped.

  In FIG. 2 again, the scaling processing unit 43 transfers the received image data to the next check processing unit 44 as it is. The check processing unit 44 transfers the received image data (image data) to the image processing unit 47.

  Further, the digital image reading apparatus 1 includes a nonvolatile memory 46 as a memory for storing white reference data. The nonvolatile memory 46 has a factory-passed state of the digital image reading apparatus 1, that is, a sheet passing path. White reference data obtained by reading the white reference plate 30 in a clean initial state is stored in advance as initial state white reference data.

  A scaling processing unit (reduction processing means) 43 performs scaling processing for enlargement / reduction in the main scanning direction in accordance with the scaling factor designated by the user using the operation unit or the like, and checks the scaled image data. To the unit 44.

  The digital image reading apparatus 1 performs main / sub independent scaling processing, but only the scanning density conversion in the main scanning direction is performed by the scaling processing unit 43 by electrical scaling. That is, since the aperture (focusing rate) of the lens 9 and the number of reading pixels on the CCD 10 are fixed, the reading density in the main scanning direction is a constant value, and the digital image reading apparatus 1 has a reading density of 600 dpi in the main scanning direction. It is configured to be.

  The scaling unit 43 converts the density of the read data at 600 dpi into arbitrary dpi by performing a thinning process and writing twice while performing an interpolation process using a line memory (not shown). For example, in order to reduce (50%) to 300 dpi, the scaling processing unit 43 performs a thinning process while interpolating adjacent pixels of 600 dpi read data to convert from 2 pixels to 1 pixel, and 1200 dpi. To enlarge (200%), one pixel is written twice while interpolating to convert it into two pixels.

  The digital image reading apparatus 1 performs reading magnification conversion in the sub-scanning direction by mechanical scaling. That is, the digital image reading apparatus 1 uses stepping motors for the traveling body motor 11 and the transport motor 28, and the CPU (not shown) changes the driving speed of these motors, thereby increasing the scanning speed of the document in the sub-scanning direction. Density conversion is performed by changing, that is, by changing the reading density in the sub-scanning direction. For example, in order to read at 300 dpi (50% reduction) with respect to a scanning speed of λ of 600 dpi, the digital image reading apparatus 1 drives a motor so as to scan at a scanning speed of 2 × λ, and 1200 dpi (200 In order to read at a magnification of%, the motor is driven so as to scan at a scanning speed of λ / 2.

  The check processing unit 44 normally outputs the image data received from the scaling processing unit 43 to the image processing unit 47 as it is during a reading operation. Next, the check processing unit 44 reads out the initial image data of the white reference plate 30 stored in the nonvolatile memory 46 and transmits it to the image processing unit 47.

  The image processing unit 47 performs correction on image data such as MTF (Modulation Transfer Function) and smoothing, which are appropriately set according to the purpose of use of the user, fixed threshold binarization, dithering, tone number conversion processing such as error diffusion, and the like. Perform various image processing.

  That is, the image processing unit 47 includes a character processing unit 70, a pattern processing unit 80, an image signal selection circuit 90, and the like. The character processing unit 70 includes an MTF correction circuit 71 and a fixed threshold binarization circuit 72. The picture processing unit 80 includes a smoothing circuit 81 and a dither processing circuit 82. The image data from the scaling processing unit 43 is input to the MTF correction circuit 71 of the character processing unit 70 and the smoothing circuit 81 of the pattern processing unit 80, respectively.

  The character processing unit 70 performs processing that makes the image clear and clear in order to improve the legibility and reproducibility of the character portion of the read image. That is, in the character processing unit 70, the image data from the scaling processing unit 43 is input to the MTF correction circuit 71, and the MTF correction circuit 71 uses the optical system of the exposure scanning optical system 12 for the input image data. An MTF correction process for correcting the blur and sharpening the image data is performed and output to the fixed threshold value binarization circuit 72. The fixed threshold binarization circuit 72 performs a binarization process on the image data that has been subjected to the MTF correction process by the MTF correction circuit 71 to generate a clear binary image, and sends it to the image signal selection circuit 90. Output.

  The pattern processing unit 80 performs processing for reproducing the pattern portion of the read image into a smooth image with rich gradation. That is, the image processing unit 80 receives the image data from the scaling processing unit 43 as input to the smoothing circuit 81, and the smoothing circuit 81 removes noise from the image data and smoothes the input image data. To the dither processing circuit 82. The dither processing circuit 82 performs a binarization process using a pseudo halftone process on the image data smoothed by the smoothing circuit 81, thereby generating a binary image rich in gradation and generating an image signal Output to the selection circuit 90.

  The image signal selection circuit 90 operates based on mode information input from a CPU (not shown) according to a reading mode set by the user in the operation unit 90, and is binarized by the character processing unit 70. One of the pattern processed images dithered by the unit 80 is selected and output to the memory controller 48.

  The memory controller 48 stores the image data (image data) subjected to the image processing by the image processing unit 47 in the memory 49 and also stores the image data stored in the memory 49 in response to a request from the I / F controller 50. Memory control is performed when transferring to the external host 100.

  The memory 49 is a memory provided to absorb a speed difference generated between the reading speed and the video transfer speed, and has a capacity for storing a plurality of pages of image data. Data stored in the memory 49 can be read and written by a CPU (not shown) via the memory controller 48.

  The I / F controller 50 controls data transfer (bus arbitration) in accordance with the connection I / F between the host 100 and the digital image reading apparatus 1 and controls various mode setting data transmitted and received from the host 100. For example, when a SCSI I / F is used as the I / F controller 50, a general-purpose SCSI controller is used as the I / F controller 50.

  The host 100 is a personal computer such as a so-called DOS / V machine. The operator of the digital image reading apparatus 1 uses the application software installed in the host 100, which is a personal computer, to check the state of the digital image reading apparatus 1 and set various modes to perform a desired scan. The operation can be executed and a digital image can be captured in the host 100.

  Next, the operation of this embodiment will be described. In this embodiment, the image data of the white reference plate 30 read while turning off the shading correction process and the image data of the white reference plate 30 stored in advance in the non-volatile memory 46 at the time of shipment from the factory are used as dust on the scanning line. And output as data for discriminating dirt.

  That is, in the digital image reading apparatus 1, first, the initial white reference data (initial white reference data) is stored in the nonvolatile memory 46 when the digital image reading apparatus 1 is shipped from the factory. That is, at the time of the white reference plate initial state capturing operation, the digital image reading apparatus 1 uses the white reference plate read image data obtained by reading the initial white reference plate 30 from the sensor 41 as the selector of the shading correction processing unit 42 in FIG. The selector 63 selects the image data received from the sensor 41 and outputs it to the scaling processing unit 43. At this time, the digital image reading apparatus 1 stops the white reference generation circuit 61.

  The scaling processing unit 43 transfers the image data received from the shading correction processing unit 42 to the next check processing unit 44 as it is, and the check processing unit 44 stores the received image data in the non-volatile memory 46 in the initial state white reference. Store as data.

  By this series of operations, the initial state image data of the white reference plate 30 is stored in the nonvolatile memory 46 as the initial state white reference data. Further, in this embodiment, as the initial state white reference data, the state of the digital image reading apparatus 1 is set to the most stable state, the white reference plate 30 is read at the time of shipment from the factory, and the read image data is converted to the initial state white reference data. It is taken in as reference data and stored in the nonvolatile memory 46.

  During the normal reading operation of the white reference plate 30, the digital image reading device 1 inputs the white reference plate read image data from the sensor 41 to the white reference generation circuit 61 of the shading correction processing unit 42 shown in FIG. The reference generation circuit 61 stores the first line of image data as it is in the volatile memory 45, but reads the data stored in the volatile memory 45 for each pixel from the second line and performs a weighted average process thereof Write back to volatile memory.

  This weighted average process is performed based on the following equation (1).

SDn (l) = (Dn (l) + SDn (l−1)) / 2 (1)
Individually, Dn (l) is the white reference plate read image data input from the sensor 41, SDn (l-1) is the white reference data of the previous line stored in the volatile memory 45, and SDn (l) is The newly generated white reference data, n, indicates the pixel position in one line and takes a value of n = 1-7200. L indicates the number of lines. When l = 1, SDn (1) = Dn (1).

  As described above, the white reference plate 30 is read and white reference data is generated and stored in the volatile memory 45. At this time, the shading correction arithmetic circuit 62 is stopped.

  Next, when shifting to a normal document reading operation, the digital image reading apparatus 1 inputs the document read image data from the sensor 41 to the shading correction calculation circuit 62 of the shading correction processing unit 42 in FIG. The circuit 62 performs shading correction on the document read image data from the sensor 41 using the white reference data stored in the volatile memory 45, and transfers it to the selector 63. At this time, as a matter of course, the white reference generation circuit 61 is stopped.

  The selector 63 selects the data received from the shading correction arithmetic circuit 62 and outputs the selected data to the scaling processing unit 43. The scaling processing unit 43 expands in the main scanning direction as described above as necessary. The image data subjected to the scaling process is output to the check processing unit 44.

  The check processing unit 44 normally outputs the image data received from the scaling processing unit 43 to the image processing unit 47 as it is during the reading operation, and the image processing unit 47 sets the MTF (Modulation) appropriately set according to the purpose of use of the user. Various image processing such as correction of image data such as Transfer Function) and smoothing, fixed threshold binarization, dithering, tone number conversion processing such as error diffusion, and the like are performed and output to the memory controller 48.

  The memory controller 48 accumulates the image data subjected to the image processing by the image processing unit 47 in the memory 49, and the image data accumulated in the memory 49 in response to a request from the I / F controller 50. Forward to.

  When the white reference plate 30 is checked, the digital image reading device 1 reads the current white reference plate read image data obtained by reading the current white reference plate 30 from the sensor 41 into the shading correction processing unit 42 of FIG. Directly input to the selector 63, the selector 63 selects the white reference plate read image data received from the sensor 41, and outputs it to the scaling processing unit 43. At this time, the white reference generation circuit 61 is stopped. The scaling processing unit 43 transfers the received image data as it is to the next check processing unit 44, and the check processing unit 44 transfers the received image data to the image processing unit 47.

  Next, the check processing unit 44 reads out the initial state image data (initial state white reference data) of the white reference plate 30 stored in the nonvolatile memory 46 and transmits the read image data to the image processing unit 47.

  The digital image reading apparatus 1 transfers the current image data and initial state white reference data of the white reference plate 30 to the host 100 via the image processing unit 47, the memory controller 48, the memory 49, and the I / F controller 50. To do.

  The host 100 checks the current image data of the white reference plate 30 and the two images of the initial state white reference data, thereby clearly confirming the influence of dust and dirt adhering to the scanning line of the white reference plate 30. be able to. For example, after a serviceman or the like performs maintenance such as cleaning of the sheet passing route, the white reference plate 30 is checked to check the current image data and initial white reference plate data of the white reference plate 30. Thus, it can be confirmed whether dust and dirt attached on the scanning line of the white reference plate 30 have been successfully removed. In this check, if dirt or the like is recognized even after cleaning, the inside of the digital image reading apparatus 1 is also cleaned on the assumption that dust or the like is still outside the cleaned range.

  As described above, the digital image reading apparatus 1 of the present embodiment is an exposure scanning optical system (scanning optical system) 12 that irradiates a conveyed document with light at a reading position and reads an image of the document with the reflected light. The predetermined white reference plate 30 is read at a predetermined time before reading the document, and the shading correction processing unit 42 stores the image data when the white reference plate 30 is read in the volatile memory 45 as read white reference data. When the image data when the original is read based on the stored white reference data is subjected to shading correction, the initial state white reference data obtained by reading the white reference plate 30 in the initial state with the exposure scanning optical system 12 is stored in the nonvolatile memory 46. The current white reference data obtained by reading the current white reference plate 30 with the exposure scanning optical system 12 in a state where the shading correction processing unit 42 is off and the non-volatile The initial state white reference data memory 46, and outputs to the host 100 as a stain of the determination data for the exposure scanning optical system 12.

  Accordingly, it is possible for a serviceman or the like to determine the influence of dust and dirt adhering to the scanning line of the white reference plate 30 from the output image data at a glance, and to accurately grasp the state of the apparatus that generates an abnormal image. It is possible to improve the accuracy of performing maintenance (cleaning of the paper passage route) by service personnel only within the range that can be reached from the outside of the device / when necessary inside the device, and reducing unnecessary maintenance time. It is possible to prevent a prolonged period of time and improve the usability of the user due to inappropriate maintenance and the efficiency of maintenance by the service person.

  In the check operation processing of the white reference plate 30, the image data is processed at the same magnification in the above processing, but the reduction processing is performed to check the influence of dust and dirt adhering to the scanning line of the white reference plate 30. You may make it do.

  In this case, when the digital image reading apparatus 1 is shipped from the factory, the white reference data in the initial state of the white reference plate 30 (initial state white reference data) is stored in the non-volatile memory 46. As described above, it is stored in the nonvolatile memory 46. That is, at the time of the white reference plate initial state capturing operation, first, as described above, the digital image reading device 1 inputs the white reference plate read image data from the sensor 41 to the selector 63 of the shading correction processing unit 42 in FIG. The selector 63 selects the image data received from the sensor 41 and outputs it to the scaling processing unit 43. At this time, the digital image reading apparatus 1 stops the white reference generation circuit 61.

  At the time of the white reference plate initial state capturing operation, the digital image reading device 1 supplies the white reference plate read image data obtained by reading the initial white reference plate 30 from the sensor 41 to the selector 63 of the shading correction processing unit 42 in FIG. The selector 63 selects the image data received from the sensor 41 and outputs it to the scaling processing unit 43. At this time, the digital image reading apparatus 1 stops the white reference generation circuit 61.

  As for the data amount per line input to the scaling processing unit 43, the data of “8 bits / pixel” is “7200 pixels”. The scaling processing unit 43 reduces the received data by 50% and transfers it to the check processing unit 44 at the next stage. At this time, the data amount per line is “8 bits / pixel” and “3600 pixels”.

  The check processing unit 44 stores the received image data in the nonvolatile memory 46 as reduced initial state white reference data.

  Through this series of operations, the initial state image data of the white reference plate 30 is stored in the nonvolatile memory 46 as the reduced initial state white reference data.

  Next, when the white reference plate 30 is checked, white reference plate read image data obtained by reading the current white reference plate 30 from the sensor 41 is directly input to the selector 63 of the shading correction processing unit 42 in FIG. 63 selects the white reference plate read image data received from the sensor 41 and outputs it to the scaling processing unit 43. At this time, the white reference generation circuit 61 is stopped. At this time, the data amount per line is “7200 pixels” for the data of “8 bits / pixel”.

  The scaling processing unit 43 reduces the received image data by 50% and transfers it to the next check processing unit 44, and the check processing unit 44 transfers the received image data to the image processing unit 47.

  Next, the check processing unit 44 reads out the initial state image data (initial state white reference data) reduced by 50% of the white reference plate 30 stored in the nonvolatile memory 46 and transmits the read image data to the image processing unit 47. .

  The digital image reading apparatus 1 transfers the current image data and the reduced initial state white reference data of the white reference plate 30 reduced by 50% to the image processing unit 47, the memory controller 48, the memory 49, and the I / F controller 50. To the host 100.

  The host 100 checks the two images of the current reference data and the initial state white reference data of the white reference plate 30 reduced by 50%, thereby affecting the influence of dust and dirt adhering to the scanning line of the white reference plate 30. Can be confirmed at a glance.

  In this way, the initial state white reference can be efficiently utilized by efficiently utilizing the scaling unit 43 which is a reduction processing means mounted on the digital image reading apparatus 1 which is generally a digital image reading apparatus for image processing. Data can be reduced and stored in the non-volatile memory 46, the size of the non-volatile memory 46 can be reduced, unnecessary maintenance time can be prevented from being prolonged at low cost, and improper maintenance can be performed. It is possible to improve the usability of the user and the efficiency of serviceman maintenance.

  Further, as shown in FIG. 5, the digital image reading apparatus 1 according to the present embodiment includes an operation unit 110. The current image and the initial image of the white reference plate 30 are displayed on the display 111 of the operation unit 110. You may make it display.

  That is, the digital image reading apparatus 1 includes an operation unit 110 as shown in FIG. 5, for example. The operation unit 110 includes a display 111, a power switch 112, a start key 113, an enter key 114, a scroll key 115, and the like. Various operation keys are provided.

  The digital image reading apparatus 1 then controls the current image of the white reference plate 30 and the white of the initial state based on the current image data of the white reference plate 30 and the initial white reference plate data under the control of a CPU (not shown). The image of the reference plate 30 is displayed on the display 111 of the operation unit 110. At this time, if there is dust or dirt on the current white reference plate 30, the dirt Pg is displayed on the current image of the white reference plate 30 as shown as dirt Pg in FIG.

  In this way, it is possible to check the influence of dust and dirt adhering to the original scanning by the digital image reading apparatus 1 alone, which is a digital image reading apparatus, and reduce the additional work by outputting it as image data outside the apparatus. Thus, the maintenance work can be made more efficient.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention can be applied to a digital image reading apparatus that performs shading correction based on a white reference plate such as a digital scanner apparatus, a digital copying apparatus, a digital facsimile apparatus, and an MFP.

1 is a schematic front view of a main part of a digital image reading apparatus to which an embodiment of a digital image reading apparatus of the present invention is applied. FIG. 2 is a main part circuit block configuration diagram of the digital image reading apparatus of FIG. 1. FIG. 3 is a detailed circuit block diagram of a shading correction processing unit of the digital copying apparatus image reading apparatus of FIG. 2. FIG. 2 is a diagram illustrating an example of white reference data of the digital image reading apparatus of FIG. 1. FIG. 2 is a plan view of an operation unit in a state where a current image and an initial image of a white reference plate are displayed on a display by the digital image reading apparatus of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital image reader 2 Main body housing | casing 3 Original glass 4 ADF
5 Illumination lamp 6 First mirror 7 Second mirror 8 Third mirror 9 Lens 10 CCD
DESCRIPTION OF SYMBOLS 11 Traveling body motor 12 Exposure scanning optical system 13 Substrate 21 Document tray 22 Pickup roller 23 Registration roller pair 24 Conveyance drum 25 Conveyance roller 26, 27 Discharge roller pair 28 Conveyance motor 29 Discharge tray 30 White reference plate 41 Sensor 42 Shading correction Processing unit 43 Scaling processing unit 44 Check processing unit 45 Volatile memory 46 Non-volatile memory 47 Image processing unit 48 Memory controller 49 Memory 50 I / F controller 61 White reference generation circuit 62 Shading correction arithmetic circuit 63 Selector 70 Character processing unit 71 MTF correction circuit 72 Fixed threshold binarization circuit 80 Picture processing unit 81 Smoothing circuit 82 Dither processing circuit 90 Image signal selection circuit 100 Host 101 CRT
110 Operation Unit 111 Display 112 Power Switch 113 Start Key 114 Enter Key 115 Scroll Key

Claims (3)

  A scanning optical system that irradiates the conveyed document with light at a reading position and reads an image of the document with the reflected light, and reads a predetermined white reference plate at a predetermined time before reading the original to read the white reference plate. A digital image reading apparatus comprising: shading correction means for storing image data at the time of reading as reference white reference data, and correcting the shading of the image data when the original is read based on the stored white reference data A non-volatile memory for storing initial white reference data obtained by reading the white reference plate in the initial state with the scanning optical system, and the current white reference plate in the scanning state when the shading correction unit is off. The current white reference data read by the optical system and the initial state white reference data of the non-volatile memory are used as dirt determination data for the scanning optical system. Digital image reading apparatus, characterized by force.   The digital image reading apparatus includes reduction processing means for reducing an image read by the scanning optical system, and the reduction processing means for initial state white reference data obtained by reading the white reference plate in the initial state by the scanning optical system. And the current white reference data obtained by reading the current white reference plate with the scanning optical system is reduced by the reduction processing means. 2. The digital apparatus according to claim 1, wherein the reduced current white reference data and the reduced initial state white reference data of the nonvolatile memory are output as dirt determination data of the scanning optical system. Image reading device. The digital image reading apparatus includes a predetermined display unit, and based on the initial state white reference data and the current white reference data, images of the initial white reference plate and the current white reference plate are displayed on the display unit. 3. The digital image reading apparatus according to claim 1, wherein the digital image reading apparatus is displayed.

Images