JP4159867B2 - Flare correction data measurement method, flare correction method, storage medium, image reading apparatus, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides flare correction data measurement for measuring flare correction data for correcting flare, which is a pseudo signal generated by scattering or reflection of incident light for reading an original, when the image of the original is read by a scanner device or a copying machine. The present invention relates to a method, a flare correction method, a storage medium storing these programs, an image reading apparatus, and an image forming apparatus.
[0002]
[Prior art]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-23226
[Patent Document 2]
Japanese Patent Laid-Open No. 10-48048
[Patent Document 3]
JP 10-1112799 A
[Patent Document 4]
JP-A-11-355636
[Patent Document 5]
Japanese Patent Laid-Open No. 9-2986665
When an image of a document is read by a scanner device or an image reading device of a copying machine, as shown in FIG. 23, the illumination light emitted from the light source 12 is not the imaging region 90 of the document 11 placed on the contact glass 10. This is a phenomenon in which the light irradiated to the area is reflected from the document 11 and is reflected or scattered by the reflector 13 or the like to irradiate the imaging area 90. When this phenomenon occurs in the image reading apparatus, the imaging region 90 is irradiated and a flare that is a pseudo signal is generated. This flare causes a change in the image density of the document in the vicinity of the imaging region, and the read signal level changes, causing an image reading defect.
[0003]
In order to eliminate the influence of this flare, for example, the surface of a reflector or the like is painted black to reduce the surface reflection. In this way, since the cost is increased by painting the surface of the reflector or the like, it is desirable to apply the coating only to the part where the flare light is generated, but in order to specify the part where the flare light is generated, It was necessary to apply black coating to each part predicted to generate a flare light image such as a reflector and to evaluate from the read image, and it took time for the evaluation and the effect was limited.
[0004]
Further, when a document is read by a copying machine or the like, the background of the document is processed by image processing called skipping. That is, for a document having a light background color, the gradation of the light background color is erased by the ground removal process so that it becomes the color of the recording paper itself. Also, if ground removal processing is not performed in order to maintain the background color, the illumination light is reflected by the document surface other than the imaging area, the light returns to the optical system, and this time it is generated by illuminating the imaging area. Due to the influence of the original surface reflection flare, the white area sandwiched between the black area and the black area is copied darkly and dirty. Furthermore, to save energy, the reading light source tends to shift from a halogen light source to a xenon light source. However, the xenon light source is known to be more affected by document surface flare than the halogen light source. is necessary.
[0005]
Therefore, for example, the image reading apparatus disclosed in Patent Document 1 is configured to display a target pixel S._xyFrom the output signal obtained from the output signal obtained from the target pixel Sxy and the peripheral pixel PS_xyA value obtained by multiplying the output signal obtained from the above and a unique reading coefficient is subtracted to read the density of the original faithfully. If the document reflectance is R, the line sensor output S is not only proportional to the document reflectance R but also influenced by the higher order of the document reflectance R, and a coefficient depending on the illumination system of the document reader is set to α (for example, α = 0.1 to 0.15), the line sensor output S is obtained by standardizing an output with a reflectance of 100% with S = 1,
S∝R + αR²+ ΑR3 + ...
Is based on the premise that And the correction output CS of the target pixel_xyIs corrected by the following correction formula.
CS_xy= S_xy-ΑΣ (S_xy・ PS_xy) / Σn_xy
However, Σn_xyIs the sum of the number of surrounding pixels
[0006]
In addition, as shown in FIG. 23A, the image evaluation method shown in Patent Document 2 is a white circular image 92 centering on the measurement position 91 and a white fan shape only in one direction around the circular image 92. The formed detection region 93 and the measurement pattern 94 in which the portion other than the detection region 93 is black are read by the image reading device to be measured, and the flare amount due to the document surface is detected based on the image signal intensity at the measurement position of the read image. is doing. Then, the position of the detection region 93 is changed with respect to the measurement position 91, and the flare amount around the measurement position 91 is detected. This measurement result data is represented by an image intensity signal at the measurement position, as shown in FIG. In this case, when the detection region is on the right side with respect to the measurement position, it indicates that particularly strong flare has occurred.
[0007]
In the flare correction method disclosed in Patent Document 3, the imaging area is divided into plane elements, the position of 2D image data of interest is i, the position of arbitrary 2D image data is j, and 2D image data I (i ), I (j) as a distance r (i, j), and a flare amount for each surface element is obtained as a flare spread function f {r (i, j)}, and the read two-dimensional image data I The flare correction is performed by applying a correction formula using the function f to (i).
[0008]
In addition, the imaging apparatus disclosed in Patent Document 4 corrects and reduces flare ghosts generated in an imaging optical system in a CCD camera with a variable aperture and focal length.
[0009]
Furthermore, in the image processing apparatus disclosed in Patent Document 5, a fine line area on the white ground in a document is detected by a reading error correction unit, and density reduction in the fine line area is corrected.
[0010]
[Problems to be solved by the invention]
In the image reading apparatus disclosed in Patent Document 1, when the line sensor output S = 1, the correction output CS of the target pixel_xy= 1−α, α is only an approximation from the total amount of reflections, and a method for deriving α is not disclosed, so that it is difficult to implement. In addition, it is known that the reflection condition varies depending on the lamp light amount distribution on the document surface and the pixel reading position with respect thereto, and since this condition is not taken into account in the correction formula, the correction accuracy is poor. .
[0011]
In addition, the image evaluation method disclosed in Patent Document 2 has the disadvantages that only one amount of flare can be detected by one measurement, and the relationship between the distance from the arbitrary reading position and the amount of flare cannot be grasped.
[0012]
The flare correction method disclosed in Patent Document 3 has a disadvantage that the flare correction accuracy is reduced because the influence of flare is corrected only on the distance r (i, j) with respect to the target image data and the direction is not taken into consideration. is there.
[0013]
Furthermore, the image pickup apparatus shown in Patent Document 4 is greatly different in configuration from a scanner apparatus or the like in which the optical system has no aperture and the focal length is always constant, and the flare to be corrected is also different. There is a disadvantage that it cannot be corrected well.
[0014]
In addition, as shown in Patent Document 5, when correcting the density decrease in the fine line region on the white background in the document, the purpose is to correct the decrease in the density of the low contrast character on the white background. There is a disadvantage in that a component affected by flare cannot be corrected from an arbitrary image in which a picture or the like is mixed.
[0015]
The present invention improves such disadvantages, and provides a flare correction data measurement method capable of accurately measuring flare correction data for correcting flare, which is a pseudo signal generated by scattering and reflection of incident light for reading an original, and flare correction A flare correction method that corrects read image data with high accuracy using data, a storage medium that stores these programs, and flare correction data are measured with high accuracy, and the read image data is corrected with high accuracy and a high-quality image is output. An object of the present invention is to provide an image reading apparatus and an image forming apparatus that can perform the above operation.
[0016]
[Means for Solving the Problems]
  The flare correction data measuring method according to the present invention includes an illuminating unit that irradiates light on a reading surface of a document placed on a document placing surface, and an imaging unit that images the reading surface with light irradiated on the reading surface of the document. And a flare correction data measurement method for an image reading device that generates image signal data from a signal output from an imaging means, wherein a point light source is provided on a measurement document having a reading surface formed of a diffuse reflection surface, The image signal intensity distribution data obtained by imaging the light reflected from the entire surface of the reading surface by the light emitted from the image pickup unit and dividing the signal output from the image pickup unit into the image area based on the light emission image area of the point light source. GenerateThe generated image signal intensity distribution data is converted to flare intensity distribution data, and the converted flare intensity distribution data andThe flare correction data is calculated from the illuminance distribution data of the reading surface detected by emitting light from the illumination means in advance.
[0017]
  the aboveFlare intensity distribution dataAnd the illuminance distribution data on the reading surface are multiplied for each image area to calculate flare correction data corresponding to the original surface.
[0018]
The flare correction method according to the present invention is a flare correction method using the flare correction data calculated by the flare correction data measuring method, wherein the image signal data of the original read by emitting light from the illumination means and the flare correction data calculated in advance are used. Thus, the image signal data in which the flare component is corrected is generated, and the read image is converted into a high-quality image from which the flare is removed.
[0019]
When correcting the flare, the image signal data of the read original is divided into the image areas of the flare correction data, and the flare correction data corresponding to the image area other than the attention data is divided with respect to the attention data of the divided image signal data. The image surface reflection flare amount is calculated from the matrix calculation, and image signal data in which the flare component is corrected by subtracting the document surface reflection flare amount calculated from the data of interest is generated to improve the quality of the read image.
[0020]
  Another flare correction method of the present invention includes an illuminating unit that irradiates light on a reading surface of a document placed on a document placing surface, and an imaging unit that images the reading surface with light irradiated on the reading surface of the document. A flare correction method for an image reading apparatus for generating image signal data from a signal output from an imaging means, wherein a point light source is provided on a measurement document having a reading surface formed of a diffuse reflection surface, and emitted from the point light source The light reflected from the entire surface of the reading surface is picked up by the image pickup means, and image signal intensity distribution data is generated by dividing the signal output from the image pickup means into image areas based on the light emission image area of the point light source, The generated image signal intensity distribution data is converted into flare intensity distribution data. From the converted flare intensity distribution data and the illuminance distribution data of the reading surface detected by emitting light from the illumination means in advance.The original scanned with the illumination meansThe image signal data is subjected to flare correction. When correcting this flare, the image signal data of the read original is divided into image areas of the flare intensity distribution data, and the flare intensity distribution corresponding to the image area other than the attention data is divided with respect to the attention data of the divided image signal data. The original surface reflection flare amount is calculated from the matrix calculation of the data and the illuminance distribution data, and the image surface data is generated by correcting the flare component by subtracting the original surface reflection flare amount calculated from the attention data, thereby improving the quality of the read image. .
[0021]
The storage medium of the present invention stores one or both of the processing program of the flare correction data measurement method and the processing program of the flare correction method, and enhances the versatility of the flare correction data measurement processing and flare correction processing.
[0022]
  An image reading apparatus according to the present invention includes an illuminating unit that irradiates light on a reading surface of a document, an imaging unit that images the reading surface with light irradiated on the reading surface of the document, and an image signal from a signal output from the imaging unit. An image reading apparatus that generates data includes arithmetic processing means and storage means, and the arithmetic processing means places a measurement original having a reading surface formed of a diffuse reflection surface and a point light source on the original placement surface. When the point light source emits light, the light reflected from the entire reading surface by the light emitted from the point light source is picked up by the image pickup means, and the light emission image area of the point light source is defined as a basic unit from the signal output from the image pickup means. Generated image signal intensity distribution data divided into the image areas,The generated image signal intensity distribution data is converted to flare intensity distribution data, and the converted flare intensity distribution data andThe flare correction data is calculated from the illuminance distribution data of the reading surface detected by emitting light from the illuminating device in advance and stored in the storage device, and the image signal data of the original read by emitting light from the illuminating device and the flare stored in the storage device. Image signal data in which the flare component is corrected by the correction data is generated, and a read image with good image quality is output.
[0023]
The storage means stores a plurality of flare correction data for each specific area of the document, or stores a plurality of flare correction data for each variable magnification when reading the document, and changes the magnification when reading the document. However, flare correction is performed using the flare correction data corresponding to the magnification, and a high-quality image is output.
[0024]
In addition, the calculation means calculates flare correction data according to the magnification when reading the original from the flare correction data at the same magnification, and does not increase the storage capacity of the storage means, and the magnification is changed even at the time of magnification. A flare correction is performed using the corresponding flare correction data, and a high-quality image is output.
[0025]
Another image reading apparatus according to the present invention includes an illuminating unit that irradiates light on a reading surface of a document, an imaging unit that images the reading surface with light irradiated on the reading surface of the document, and a signal output from the imaging unit. An image reading apparatus that generates image signal data includes an illuminance distribution data storage unit, an arithmetic processing unit, and a flare intensity distribution data storage unit. The illuminance distribution data storage unit is a reading detected by emitting light from an illumination unit in advance. The illuminance distribution data of the surface is stored, and the arithmetic processing means outputs a point light when a measurement original having a reading surface formed of a diffuse reflection surface and having a point light source is placed on the original placement surface and the point light source emits light. The light reflected from the entire surface of the reading surface by the light emitted from the light source is picked up by the image pickup means, and the image signal intensity divided from the signal output from the image pickup means into the image area based on the light emission image area of the point light source Data is generated, the generated image signal intensity distribution data is converted into flare intensity distribution data, the converted flare intensity distribution data is stored in the flare intensity distribution data storage means, and the image signal of the original read by emitting light from the illumination means The flare intensity distribution data stored in the data, the flare intensity distribution data storage means, and the illuminance distribution data stored in the illuminance distribution data storage means generate flare-corrected image signal data.
[0026]
In the flare intensity distribution data storage means, a plurality of flare intensity distribution data is stored for each specific area of the document, or a plurality of flare intensity distribution data is stored for each variable magnification when the document is read, and according to the variable magnification. The flare correction is performed to output a high quality image.
[0027]
An image forming apparatus according to the present invention includes the above-described image reading apparatus, and forms an image using image data from which flare is output from the image reading apparatus to form a high-quality image.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing the configuration of the present invention. As shown in the figure, the digital copying machine 1 has a copying machine main body 2, an automatic document feeder (hereinafter referred to as ADF) 3, and an automatic sorting device 4. The copying machine main body 2 includes a scanner unit 5 that reads a document, and an image forming unit 9 that includes a writing unit 6, an engine unit 7, and a paper feeding unit 8. The ADF 3 sends the document to be read to the scanner unit 5 and collects the document read by the scanner unit 5.
[0029]
As shown in the perspective view of FIG. 2A and the side view of FIG. 2B, the scanner unit 5 includes a light source 12, a reflector 13, and a mirror for irradiating reading light onto a document 11 placed on a contact glass 10. The first traveling body 15 having 14, the second traveling body 17 having a plurality of mirrors 16, and the first traveling body 15 and the second traveling body 17 are parallel to the contact glass 10 by the rotation of the drive motor 18. Drive transmission means 19 that moves to the lens, a lens 20 that condenses the light from the mirror 8 of the second traveling body 17, a one-dimensional imaging device 21 that comprises, for example, a line CCD, on which the light collected by the lens 20 is incident, and An output port 22 is provided. Then, the document sent by ADF 3 is scanned and read.
[0030]
The writing unit 6 includes a laser light source, a polygon mirror, and the like, and emits a laser beam 23 including image information to the engine unit 7. The engine unit 7 includes an image forming unit 24, a primary transfer unit 25, a secondary transfer unit 26, and a fixing unit 27, as shown in the configuration diagram of FIG. The image forming unit 24 includes a charging charger 29 and a color developing unit 30 and a drum cleaning unit 31 made of cyan (C), magenta (M), yellow (Y), and black (K) disposed around the photosensitive member 28. An electrostatic latent image is formed on the photosensitive member 28 charged by the charging charger 29 by the laser beam 23 emitted from the writing unit 6, and the formed electrostatic latent image is visualized by the color developing unit 30 to form a toner image. Form. The primary transfer unit 25 includes an intermediate transfer belt 32, a primary transfer unit 33, a tension roller 34, a secondary transfer roller 35, a cleaning unit 36, and a reference position sensor 37, and intermediates a toner image formed on the photoconductor 28. Primary transfer is performed on the transfer belt 32 to superimpose toner images of respective colors. The intermediate transfer belt 32 is separated from the surface of the photosensitive member 28 by a contact / separation mechanism except when the toner image on the photosensitive member 28 is primarily transferred, and is pressed against the surface of the photosensitive member 28 only when the image is primarily transferred to the intermediate transfer belt 32. Is done. The secondary transfer unit 26 secondarily transfers the toner image transferred to the intermediate transfer belt 32 onto the recording paper. The fixing unit 27 fixes the toner image transferred to the recording paper with heat and pressure. The paper feed unit 8 includes a plurality of paper feed cassettes 38 a to 38 c and a manual feed tray 39, and sends recording paper to the secondary transfer unit 26. The automatic sorting device 4 has a plurality of sorting bins 40a to 40n, and sorts and discharges the recording paper on which images are formed.
[0031]
As shown in the block diagram of FIG. 4, the control unit 41 of the digital copying machine 1 includes a central control unit 42, an A / D conversion unit 43, a shading correction unit 44, an image signal generation unit 45, an arithmetic processing unit 46, A program storage unit 47, a data storage unit 48, a correction data storage unit 49, an image processing unit 50, an external output unit 51, and an external storage medium control unit 52 are provided. The central control unit 32 has a CPU for controlling the operation of the entire apparatus, and manages the operation of the entire apparatus under various printing conditions input from the operation display unit 53 when reading and printing the image of the document 11. As shown in FIG. 5, the data storage unit 48 includes an illuminance distribution data storage area 481, an image signal intensity distribution data storage area 482, a flare intensity distribution data storage area 483, and an image data storage area 484. The image processing unit 50 includes an image recognition unit 54, a scaling unit 55, a filter unit 56, a γ correction unit 57, and a gradation processing unit 58. The external storage medium control unit 52 controls input / output from the external storage medium 59 such as a flexible disk or an optical disk.
[0032]
When the image forming cycle of the document 11 read by the scanner unit 5 in the digital copying machine 1 is started, if the image to be formed is one color, a toner image is formed on the photosensitive member 28 based on the image data of the read document 11, The formed toner image is primarily transferred to the intermediate transfer belt 32. The secondary transfer unit 26 secondarily transfers the toner image onto the recording paper fed in accordance with the tip of the toner image transferred to the intermediate transfer belt 32. The recording paper onto which the toner image has been transferred is sent to the fixing unit 27 and fixed by heating and pressing. The recording paper on which the toner image is fixed is discharged to the automatic sorting device 4. Further, the toner remaining on the intermediate transfer belt 32 is collected by the cleaning unit 36.
[0033]
When the image to be formed has two or more colors, the scanner 11 reads the document 11 based on the detection of the reference mark provided on the intermediate transfer belt 32 by the reference position sensor 37, and the photosensitive member 28 is read by the read image data. Then, a toner image of the first color is formed, and the toner image formed on the photoreceptor 28 is primarily transferred to the intermediate transfer belt 32. Subsequently, a second color toner image is formed on the photosensitive member 28, and the toner image formed on the photosensitive member 28 is primarily transferred to the intermediate transfer belt 32. The image formation on the photoreceptor 28 and the primary transfer on the intermediate transfer belt 32 are repeated for each color. That is, when forming a two-color image, the intermediate transfer belt 32 is rotated twice, and when forming a full-color image, the intermediate transfer belt 32 is rotated four times. The toner images thus transferred are primarily transferred to the intermediate transfer belt 32 to superimpose the images of the respective colors without positional deviation. After the toner image of a predetermined color is transferred to the intermediate transfer belt 32, the toner image is secondarily transferred to the recording paper fed in accordance with the leading end of the toner image transferred to the intermediate transfer belt 32, and heated by the fixing unit 27. , Press to fix.
[0034]
As described above, when the image of the document 11 is read by the scanner unit 5, the light emitted from the illumination light emitted from the light source 12 to a region other than the imaging region of the document 11 placed on the contact glass 10 is recorded. Is reflected from the reflector 13 and reflected or scattered by the reflector 13 or the like to irradiate the imaging region to generate a flare that is a pseudo signal. This flare causes a change in the image density of the document in the vicinity of the imaging region, and the read signal level changes, causing an image reading defect. In order to correct this flare, a flare correction data measurement and flare correction processing program is stored in advance in the program storage unit 47 of the control unit 41, and flare correction data is measured in advance and stored in the correction data storage unit 49. deep. First, the configuration and processing when measuring the flare correction data will be described.
[0035]
  For measurement of flare correction data, as shown in the configuration diagram of FIG. 6A, a point light source device 60 and a dedicated document 61 for flare measurement are used.Point light source device 60Includes a light source device 62, an optical fiber bundle 63, an optical fiber 65 connected to the optical fiber bundle 63 with a connection jig 64, and a fixing jig 66 for fixing the optical fiber 66 to the dedicated document 61. The light source device 62 uses a halogen light source when a halogen lamp is used as the light source 12 of the scanner unit 5. The dedicated original 61 is of A3 size, for example, and the reading surface that comes into contact with the contact glass 10 is formed by a diffuse reflection surface. As shown in FIG. 6B, a small hole for fixing the tip of the optical fiber 66 to the measurement point. 67 is provided, and the tip of the optical fiber 66 is fixed to the hole 67 with a fixing jig 66 to form a point light source 68 on the reading surface of the dedicated original 61. Here, when the dedicated document 61 transmits light emitted from the tip of the optical fiber 66, the tip of the optical fiber 66 may be fixed to the surface of the dedicated document 61 without providing the hole 67. . The light emitting portion of the point light source 68 is actually difficult to fit within one pixel and has a certain image area. Therefore, the light emission image area of the point light source 68 is set as a basic unit for flare measurement and flare correction. The operation display unit 53 includes a screen for setting flare measurement, a setting function, a touch panel, an operation function for starting flare measurement, and the like.
[0036]
Processing when measuring flare correction data using the point light source device 60 and the original 61 for flare measurement will be described with reference to the flowchart of FIG.
[0037]
First, the light source 12 of the scanner unit 5 is turned on in advance, the illuminance of the document surface is measured with an illuminometer, etc., and the illuminance distribution data for each basic unit of the flare intensity distribution is created to store the data storage unit 48 of the control unit 41. It is stored in the illuminance distribution data storage area 481 (step S1). As shown in the illuminance distribution contour line display example of FIG. 8, the illuminance distribution on the original surface has the highest light intensity in the imaging area 69 and decreases as the distance from the imaging area 69 increases. The light intensity of the imaging area 69 is set to 1.0 and converted into a relative value according to the light intensity, and the document surface illuminance distribution data 70 shown in FIG. 9 is created. Here, the main scanning direction is a direction orthogonal to the moving direction of the first traveling body 15 and the second traveling body 17, and the sub-scanning direction is the moving direction of the first traveling body 15 and the second traveling body 17. .
[0038]
In this state, the dedicated original 61 with the point light source 68 fixed thereon is placed on the contact glass 10, and the flare measurement is set by operating the operation display unit 53 to start flare measurement (step S2). When the flare measurement is started, the light source device 62 is turned on, the point light source 68 is emitted, and the first traveling body 15 and the second traveling body 17 are moved from the front end of the dedicated document 61 without turning on the light source 12 of the scanner unit 5. An optical signal scanned to the end and reflected by the reading surface of the dedicated original 61 is received by the one-dimensional image sensor 21 (step S3). The one-dimensional imaging device 21 converts the received optical signal into an electrical signal and sends it to the control unit 41. The control unit 41 converts the sent signal into a digital signal by the A / D conversion unit 43, shading correction of the converted digital signal by the shading correction unit 44, and a dedicated document 61 having a point light source 68 by the image signal generation unit 45. Are stored in the image data storage area 484 of the data storage unit 48 (step S4). The image data stored in the image data storage area 484 is generated as image signal intensity distribution data cut out for each basic unit by the arithmetic processing unit 46 and divided into basic units, and the image signal intensity distribution data storage area of the data storage unit 48 is generated. It is stored in 482 (steps S5 and S6). The data of each basic unit of the image signal intensity distribution data is an average value obtained by dividing the reading value of each basic unit by the number of pixels of the basic unit. For example, FIG. 10 shows a display example 71 of an image signal intensity distribution in which the number of pixels in the basic unit is 25 and the main scanning direction and the sub-scanning direction each have 17 regions. As shown in FIG. 10, the image signal intensity is the highest in the area of the point light source 68, and areas having different image signal intensity due to flare are dispersed in the peripheral area. The basic unit may be one pixel, and a unit that seems to be optimal may be determined according to the characteristics of the scanner unit 5.
[0039]
Next, the arithmetic processing unit 46 extracts the image signal intensity distribution data stored in the image signal intensity distribution data storage area 482 and calculates the flare intensity distribution (step S7). Since the image signal intensity distribution data is the degree of flare influence on the surrounding image by the point light source 68, the basic unit of interest is converted into the flare intensity distribution which is the influence degree of flare received from the periphery, and the flare intensity distribution data is stored. Store in area 483. In this conversion processing, a flare intensity distribution is created by performing point-symmetrical movement about the basic unit having the point light source 68 with respect to the image signal intensity distribution data. For example, the basic unit X22 having the point light source 68 of the image signal intensity distribution data 72 shown in FIG. 11A is displaced to the position of the basic unit X22 and the basic unit X44 to the position of the basic unit X22. The flare intensity distribution data 73 shown in FIG. For example, if the flare influence amount from the basic unit X33 is 0.015 in the region 1 to the left of the basic unit X33 having the point light source 68, when the position of the left 1 is noted, the flare amount entering here is It is 0.015 because it can be regarded as entering from the right 1 direction.
[0040]
  Thereafter, the arithmetic processing unit 46 calculates the flare intensity distribution data stored in the flare intensity distribution data storage area 483 andIlluminance distribution data storage area 481The illuminance distribution data stored in the above is taken out, and both data are multiplied for each element to calculate the flare correction data in consideration of the illuminance distribution on the document surface, and stored in the correction data storage unit 49 (step S8). An example of actual flare correction data 74 is shown in FIG.
[0041]
Next, processing when performing flare correction using flare correction data when the scanner unit 5 reads an image of the document 11 will be described with reference to a flowchart of FIG. In this case, it is assumed that the image data storage area 484 of the data storage unit 48 has a storage capacity for storing image data for all images of the document 11.
[0042]
When the document 11 is placed on the contact glass 10, the magnification is set to 100% on the operation display unit 53, the flare correction process is designated, and the start button is pressed, the light source 12 that illuminates the document 11 emits light to the imaging region. , The first traveling body 15 and the second traveling body 17 move and scan from the beginning to the end of the document 11 to execute image reading, and the reflected light from the document 11 is applied to the one-dimensional image sensor 21. Condensing light (step S11). The one-dimensional imaging device 21 converts the received optical signal into an electrical signal and sends it to the control unit 41. The control unit 41 converts the sent signal into a digital signal by the A / D conversion unit 43, shading correction of the converted digital signal by the shading correction unit 44, and generation of image signal data of the document 11 by the image signal generation unit 45 Then, it is stored in the image data storage area 484 of the data storage unit 48 (steps S12 and S13). Next, the arithmetic processing unit 46 extracts the flare correction data stored in the correction data storage unit 49 and the image signal data stored in the image data storage area 484, and corrects the flare component by performing a matrix operation on the flare correction data and the image signal data. The calculated image signal data is calculated and stored in the image data storage area 484 (steps S14, S15, S16). For example, as shown in FIG. 14, the matrix calculation of the flare correction data and the image signal data uses the flare correction data 74 for the flare amount affected by the region of interest X33 in the image signal data 75 and the region X21. K11 × X21 / K23, and the flare amount affected by the region X31 is K21 × X31 / K23. If this calculation is performed on the image signal data of all areas other than the attention area X33, the total flare amount for each peripheral pixel is multiplied by X33 / 255, and subtracted from the reading value of the attention area X33, the influence of flare Image signal data with no image can be obtained. By performing this process on all image signal data, flare-corrected image signal data can be generated.
[0043]
The image processing unit 50 extracts the flare correction image signal data stored in the image data storage area 484 and performs various processes. For example, the image recognizing unit 54 determines whether it is a character region or a picture region according to image signal data, the scaling unit 55 performs enlargement, reduction, or equal magnification processing in the main scanning direction, and the filter unit 56 performs an image forming unit. The smoothing process and the sharpening process are performed using an M × N spatial filter based on the frequency characteristics of 9 and the determination result of the image recognition unit 54. Further, the γ correction unit 57 performs correction processing by changing the γ curve based on the frequency characteristics of the image forming unit 9 and the determination result of the image recognition unit 54, and the gradation processing unit 58 performs the frequency processing of the image forming unit 9. Quantization such as dither processing is performed based on the determination result of the image recognition unit 54. The various processed image data is sent to the image forming unit 9, and the image forming unit 9 forms an image on the recording paper. If requested, corrected image signal data is output from the external output unit 51.
[0044]
For example, as shown in FIG. 15A, a document 11 having a narrow white area 77 sandwiched between wide black areas 76 by partially cutting a white area of white plain paper so that the influence of flare appears significantly. , The original 11 is read by the scanner unit 5, and an image 78 formed on the recording paper without performing the flare correction processing is shown in (b), and an image 79 formed on the recording paper by performing the flare correction processing is shown in (b). c). Here, the black region is a portion where the original 11 is cut off and the pressure plate of the scanner unit 5 is opened and light is not intentionally reflected. As shown in FIG. 15B, the reading value of the narrow white area 77 sandwiched between the wide black areas 76 is smaller than the other white areas, but as shown in FIG. 15C, the reading is narrowed by performing the flare correction processing. The white area 77 can be made uniform with other white areas.
[0045]
In addition, the flare correction process when the image data storage area 484 of the data storage unit 48 does not have a storage capacity for storing image data for all the images of the document 11 is shown in the flowchart of FIG. When the image of the document 11 is read by the unit 5, the flare correction data is extracted from the correction data storage unit 49 by the calculation processing unit 46 (step S21), and the image signal data generated by the image signal generation unit 45 is subjected to matrix calculation. For example, when the whole area in the main scanning direction of the read image is one line, image signal data for seven lines is held in the image data storage area 484 (steps S22 and S23). The flare component is corrected using the held image signal data and flare correction data for the seven lines (step S24). The flare-corrected image signal data is sequentially processed and output by the image processing unit 50 (step S25). In this way, flare correction can be performed without being affected by the storage capacity of the data storage unit 48, and high quality images can be output stably.
[0046]
When flare correction is performed on the image signal data read by the scanner unit 5 in this way, it is necessary to correct the entire image area with high accuracy using the flare correction data. Further, the normal scanner unit 5 sometimes reads an image of the document 11 with a variable magnification, and it is necessary to correct flare with high accuracy even when reading with the variable magnification. Therefore, for example, the document reading surface 10a of the contact glass 10 on which the A3 document 11 is placed is divided into a plurality of regions, for example, six parts as shown in FIG. 16A or nine parts as shown in FIG. The flare correction data is measured for each area and stored in the correction data storage unit 49. When the read image signal data is subjected to flare correction, the flare correction is preferably performed using the flare correction data of the area where the image signal data is read. Thus, by performing flare correction with the corresponding flare correction data for each area where the image of the document 11 is read, the read image signal data can be corrected with high accuracy.
[0047]
Further, when the image of the original 11 is read by the scanner unit 5 with the magnification changed, as shown in FIG. 17B, when 100 pixels in the sub-scanning direction of the same size image data is used as a reference, As shown in FIG. 17 (a), when 200 pixels of the image data are scaled by 50%, 50 pixels of the image data are first read as shown in FIG. 17 (c). The read image signal data is subjected to image processing by the image processing unit 50 to adjust the magnification in the main scanning direction and the sub-scanning direction. When the magnification is 200%, the scanning linear velocity is slower than that at the normal magnification, and when the magnification is 50%, the scanning linear velocity is faster than that at the same magnification. For this reason, the corresponding flare correction data also changes. Therefore, a plurality of flare correction data corresponding to the variable magnification is stored in the correction data storage unit 49, and when flare correction is performed on the image signal data, the flare correction data corresponding to the variable magnification is extracted and flare corrected. Also good.
[0048]
Further, for example, in the image data of the entire surface of the A3 size document 11, if flare correction data at the same magnification is generated in a region 80 of 120 mm × 20 mm as shown in FIG. As shown in FIG. 18B, the area 81 of the flare correction data at the time of zooming needs to be twice as large as the area 80 of the flare correction data at the time of magnification, and the area of the flare correction data at the time of 50% zooming 82 is required to be ½ times. If the basic unit at the same magnification for correcting the flare is, for example, main scanning 30 × sub scanning 10 pixels, main scanning 30 × sub scanning 20 pixels at 200% magnification, and main scanning 30 × at 50% magnification. The flare correction calculation may be performed using the sub-scanning 5 pixels as a basic unit. That is, in this case, when the flare correction is performed by the arithmetic processing unit 46, the flare correction data at the same magnification stored in the correction data storage unit 49 is used,
Number of sub-scanning pixels = (number of sub-scanning basic pixels at the same magnification x scaling factor)
By determining the image area to which the flare correction at the time of zooming is applied and performing the flare correction, the flare correction data itself only needs to store the data at the same magnification.
[0049]
In the above description, the illuminance distribution data is created by measuring the illuminance on the document surface with an illuminometer or the like, but it may be calculated from the illuminance distribution image captured by the CCD camera. The illuminance distribution measuring apparatus for creating illuminance distribution data from the illuminance distribution image picked up by the CCD camera, as shown in the block diagram of FIG. 19, is a diffuse transmission plate 85 placed on the contact glass 10, a CCD camera 86, and an arithmetic operation. A processing device 87 is included. As shown in the cross-sectional view of FIG. 20, the diffuse transmission plate 85 includes, for example, a diffuse reflection film 851 and an ND filter (neutral density filter) 852. Then, the light source 12 is caused to emit light, and the diffused light 88 from above the diffuse transmission plate 85 is picked up by the CCD camera 86, and the image of the diffused light is processed by the arithmetic processing unit 87 to calculate the two-dimensional illuminance distribution data. The copying machine 1 is stored in the illuminance distribution data storage area 481 of the feed control unit 4. When calculating the two-dimensional illuminance distribution data by this arithmetic processing unit 87, the average value of the illuminance distribution in the entire area of the document surface may be used as the illuminance distribution data, or the average value of several representative document surfaces may be used as the illuminance distribution data. It is also good. In the case of a color scanner, it is sufficient to have RGB data. In this way, by generating the two-dimensional illuminance distribution data by causing the light source 12 to emit light, the flare component that affects the image signal data can be accurately corrected.
[0050]
In the above description, the flare intensity distribution is calculated from the image signal intensity distribution data, the flare correction data is calculated from the calculated flare intensity distribution data and the illuminance distribution data detected in advance, and stored in the correction data storage unit 49 in advance. The case where the flare correction is performed using the flare correction data stored in the correction data storage unit 49 when the image of the document 11 is read has been described. However, the illuminance distribution data and the flare intensity distribution data are preliminarily described. Are stored in the illuminance distribution data storage area 481 and the flare intensity distribution data storage area 483 of the data storage unit 48, and when the image of the document 11 is read and flare correction is performed, the flare intensity distribution data and the illuminance distribution data are read out. Flare correction may be performed.
[0051]
A description will be given of a case where flare intensity distribution data and illuminance distribution data are read and flare correction is performed when flare correction is performed by reading the image of the document 11.
[0052]
First, a dedicated document 61 with a point light source 68 fixed thereon is placed on the contact glass 10, and flare measurement is performed by causing the point light source 68 to emit light without turning on the light source 12 of the scanner unit 5. As shown in FIG. The intensity distribution data 72 is generated and stored in the image signal intensity distribution data storage area 482 of the data storage unit 48. A flare intensity distribution is calculated by the arithmetic processing unit 46 from the image signal intensity distribution data 72 stored in the image signal intensity distribution data storage area 482, and the flare intensity distribution data 73 is stored in the flare intensity distribution data storage area 483.
[0053]
In this state, the scanner unit 5 reads the image of the document 11 and stores the read image signal data 75 in the image data storage area 484 of the data storage unit 48. Next, as shown in FIG. 21, the arithmetic processing unit 46 of the control unit 41 extracts the flare intensity distribution data 73 stored in the flare intensity distribution data storage area 483 and the illuminance distribution data 89 stored in the illuminance distribution data storage area 481. Then, flare correction is performed by performing matrix calculation with the image signal data 75 stored in the image data storage area 484. In this matrix calculation, for example, the flare amount that the attention area X33 of the image signal data 75 is influenced by the area X21 is F11 × S11 × X21 / F23 when the flare intensity distribution data 73 and the illuminance distribution data 89 are used. The flare amount influenced by F21 × S21 × X31 / F23. If this calculation is performed on all image signal data other than the region X33, and the total flare amount for each peripheral pixel is multiplied by X33 / 255 and subtracted from the reading value of the attention region X33, there is no flare effect. Image signal data is obtained. This operation is performed on all the image signal data to generate flare correction image signal data, which is stored in the correction data storage unit 49. As described above, by correcting the flare component that affects the image signal data 75 from the flare intensity distribution data 73 and the illuminance distribution data 89, a high-quality image can be read and a high-quality image can be formed.
[0054]
In the above description, the case where the image of the document 11 can be scaled and read by the scanner unit 5 has been described. However, as shown in the perspective view of FIG. 22A and the side view of FIG. The present invention can be similarly applied to the scanner unit 5 a in which the traveling body 84 is provided with the same-magnification imaging element 83 together with the light source 12, the reflector 13, and the lens 20 that irradiates the reading light to the placed document 11.
[0055]
In the above description, the digital copying machine 1 has been described. However, in the scanner device that reads an image of the document 11 and outputs it to a terminal device such as a personal computer, flare correction data is generated in the same manner, and read by the generated flare correction data. The flare correction of the image signal data can be performed.
[0056]
Further, in the above description, the case where the flare measurement and flare correction data creation and flare correction processing programs are stored in the program storage unit 47 of the control unit 41 has been described. Are stored in the external storage medium 59, the flare correction processing program is stored in the program storage unit 47, and the flare measurement and flare correction are performed from the external storage medium 59 by the central control unit 42 when creating the flare correction data. The flare correction data may be created by reading a data creation processing program. Also, the flare measurement / flare correction data creation and flare correction processing program is stored in the external storage medium 59, and the flare measurement processing program and the flare correction data creation processing program are stored in the external storage medium 59. In addition, when creating flare correction data and performing flare correction, the central control unit 42 may read these processing programs from the external storage medium 59. By storing these processing programs in the external storage medium 59 in this way, the versatility of flare correction is enhanced and a high-quality image with flare correction is read and formed even in existing copying machines and scanner devices. be able to.
[0057]
【The invention's effect】
As described above, the present invention provides a point light source on a measurement document having a reading surface formed of a diffuse reflection surface, and images the light reflected from the entire surface of the reading surface by light emitted from the point light source. Image signal intensity distribution data is generated from the signal output from the imaging means, divided into image areas with the light emission image area of the point light source as a basic unit, and the generated image signal intensity distribution data and the illumination means are pre-emitted to detect By calculating the flare correction data from the illuminance distribution data on the reading surface, it is possible to detect the flare state due to the document surface reflection component with a simple configuration.
[0058]
Also, the flare state due to the document surface reflection component is detected accurately by multiplying the image signal intensity distribution data and the illuminance distribution data of the reading surface for each image area to calculate flare correction data corresponding to the document surface. be able to.
[0059]
Further, by generating image signal data in which the flare component is corrected based on the image signal data of the original read by emitting light from the illumination unit and the flare correction data calculated in advance, the read image has a high quality image obtained by removing the flare. Can be converted to
[0060]
When correcting the flare, the image signal data of the read original is divided into the image areas of the flare correction data, and the flare correction data corresponding to the image area other than the attention data is divided with respect to the attention data of the divided image signal data. By calculating the original surface reflection flare amount from the matrix calculation and subtracting the original surface reflection flare amount from the data of interest to generate image signal data with corrected flare components, the quality of the scanned image can be easily processed. Can be improved.
[0061]
When the image signal data of the original is subjected to flare correction, the read image signal data can be corrected by a simple process by performing flare correction using the flare intensity distribution data and illuminance distribution data stored in advance. It is possible to quickly output a high-quality image from which flare is removed.
[0062]
In addition, by storing one or both of the processing program of the flare correction data measurement method and the processing program of the flare correction method in the storage medium, the versatility of the flare correction data measurement processing and the flare correction processing is improved, An existing scanner device or copying machine can output a read image from which flare is removed.
[0063]
Further, when a measurement original having a reading surface formed of a diffuse reflection surface and having a point light source is placed on the original placement surface and the point light source emits light on the image reading device, reading is performed by light emitted from the point light source. The light reflected from the entire surface is picked up by the image pickup means, and image signal intensity distribution data is generated by dividing the signal output from the image pickup means into image areas based on the light emission image area of the point light source, and the generated image The flare correction data is calculated from the signal intensity distribution data and the illuminance distribution data of the reading surface detected by emitting light from the illumination means in advance and stored in the storage means, or the image signal intensity distribution data is converted into flare intensity distribution data. Store the image signal data of the original read by emitting light from the illumination means and use the stored flare correction data or flare intensity distribution data and illuminance distribution data to compensate for the flare component. By, a good read image in the image quality can be stably output.
[0064]
Also, the image reading apparatus stores a plurality of flare correction data and flare intensity distribution data for each specific area of the document, or stores a plurality of flare correction data and flare intensity distribution data for each variable magnification when reading the document. As a result, even if the magnification is changed when the document is read, flare correction corresponding to the magnification can be performed and a high-quality image can be output.
[0065]
The arithmetic processing means calculates the flare correction data according to the magnification when reading the original from the flare correction data at the same magnification, thereby increasing the magnification even at the time of magnification without increasing the storage capacity of the storage means. It is possible to output a high-quality image by performing flare correction using the flare correction data corresponding to.
[0066]
Furthermore, a high-quality image can be stably formed by providing the image reading apparatus in an image forming apparatus and forming an image using image data from which flare output from the image reading apparatus is removed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a digital copying machine according to the present invention.
FIG. 2 is a configuration diagram of a scanner unit.
FIG. 3 is a configuration diagram of an engine unit.
FIG. 4 is a block diagram illustrating a configuration of a control unit.
FIG. 5 is a configuration diagram of a data storage unit.
FIG. 6 is a configuration diagram of an apparatus for measuring flare correction data.
FIG. 7 is a flowchart showing measurement processing of flare correction data.
FIG. 8 is a display diagram of illuminance distribution contour lines when the illuminance distribution on the document surface is measured.
FIG. 9 is a configuration diagram of illuminance distribution data on a document surface.
FIG. 10 is a display diagram of an image signal intensity distribution during measurement of flare correction data.
FIG. 11 is an explanatory diagram showing a process of creating flare correction data from an image signal intensity distribution.
FIG. 12 is an explanatory diagram showing an example of flare correction data.
FIG. 13 is a flowchart showing a flare correction process.
FIG. 14 is an explanatory diagram showing flare correction processing.
FIG. 15 is a schematic diagram showing an image with and without flare correction processing.
FIG. 16 is a schematic diagram illustrating a state in which a reading surface is divided into a plurality of parts when creating flare correction data.
FIG. 17 is a schematic diagram illustrating a read pixel area at the same magnification and at a variable magnification.
FIG. 18 is a schematic diagram showing a flare correction data area at the time of equal magnification and variable magnification.
FIG. 19 is a configuration diagram of an illuminance distribution measuring apparatus.
FIG. 20 is a cross-sectional view showing a configuration of a diffuse transmission plate of the illuminance distribution measuring apparatus.
FIG. 21 is an explanatory diagram showing flare correction processing using flare intensity distribution data and illuminance distribution data.
FIG. 22 is another configuration diagram of the scanner unit.
FIG. 23 is an explanatory diagram of flare caused by reflection from a reading surface.
FIG. 24 is an explanatory diagram showing a conventional image evaluation method.
[Explanation of symbols]
1; Digital copier, 2; Copier body, 3; ADF, 4; Automatic sorting device,
5; scanner unit, 6; writing unit, 7; engine unit, 8; paper feeding unit,
9: Image forming unit, 10: Contact glass, 11: Document, 12: Light source,
13; reflector, 14; mirror, 15; first traveling body, 16; mirror,
17; second traveling body, 19; drive transmission means, 20; lens,
21; one-dimensional imaging device, 24; image forming unit,
25; primary transfer unit; 26; secondary transfer unit; 27; fixing unit;
41; control unit, 42; central control unit, 46; arithmetic processing unit,
47; program storage unit, 48; data storage unit, 49; correction data storage unit,
60: Point light source device, 61: Original document for flare measurement.

Claims (17)

An illuminating means for irradiating light on the reading surface of the original placed on the original placement surface, an imaging means for imaging the reading surface with light irradiated on the original reading surface, and an image from a signal output from the imaging means A flare correction data measurement method for an image reading device that generates signal data,
A point light source is provided on a measurement document whose reading surface is formed of a diffuse reflection surface, and the light reflected from the entire surface of the reading surface by the light emitted from the point light source is imaged by the imaging means, and the point output from the signal output from the imaging means Image signal intensity distribution data divided into image areas with the light emission image area as a basic unit is generated, the generated image signal intensity distribution data is converted into flare intensity distribution data, and the converted flare intensity distribution data and the illumination means in advance A flare correction data measurement method comprising calculating flare correction data from illuminance distribution data of a reading surface detected by emitting light. The flare correction data measurement method according to claim 1, wherein the flare correction data is calculated by multiplying the flare intensity distribution data and the illuminance distribution data of the reading surface for each image area. A flare correction method using the flare correction data calculated by the flare correction data measurement method according to claim 1,
A flare correction method comprising: generating image signal data in which a flare component is corrected based on image signal data of a document read by emitting light from an illumination unit and flare correction data calculated in advance.   The image signal data of the read original is divided into image areas of flare correction data, and the original surface is calculated from matrix calculation of flare correction data corresponding to image areas other than the attention data with respect to the attention data of the divided image signal data. 4. The flare correction method according to claim 3, wherein the flare correction method generates image signal data by calculating a reflection flare amount and subtracting the calculated document surface reflection flare amount from the data of interest to correct the flare component. An illuminating means for irradiating light on the reading surface of the original placed on the original placement surface, an imaging means for imaging the reading surface with light irradiated on the original reading surface, and an image from a signal output from the imaging means A flare correction method for an image reading apparatus for generating signal data, comprising:
A point light source is provided on a measurement document whose reading surface is formed of a diffuse reflection surface, and the light reflected from the entire surface of the reading surface by the light emitted from the point light source is imaged by the imaging means, and the point output from the signal output from the imaging means Image signal intensity distribution data divided into image areas with the light emission image area as a basic unit is generated, the generated image signal intensity distribution data is converted into flare intensity distribution data, and the converted flare intensity distribution data and the illumination means in advance A flare correction method for performing flare correction on image signal data of a document read by emitting light from the illumination means from illuminance distribution data of a reading surface detected by emitting light .   The image signal data of the read original is divided into the image areas of the flare intensity distribution data, and the flare intensity distribution data and the illuminance distribution data corresponding to the image areas other than the attention data are divided with respect to the attention data of the divided image signal data. 6. The flare correction method according to claim 5, wherein the original surface reflection flare amount is calculated from matrix calculation, and the image surface data is generated by correcting the flare component by subtracting the original surface reflection flare amount calculated from the attention data.   A storage medium storing a processing program of the flare correction data measurement method according to claim 1.   A storage medium storing the processing program for the flare correction method according to claim 3.   A storage medium storing the processing program for the flare correction data measurement method according to claim 1 and the processing program for the flare correction method according to any one of claims 3 to 6. In an illuminating unit that irradiates light on a reading surface of a document, an imaging unit that images the reading surface with light irradiated on the reading surface of the document, and an image reading apparatus that generates image signal data from a signal output from the imaging unit ,
Arithmetic processing means and storage means;
The arithmetic processing means is configured such that when a measurement original having a reading surface formed of a diffuse reflection surface and having a point light source is placed on the original placement surface and the point light source emits light, the light emitted from the point light source emits light on the reading surface. Light reflected from the entire surface is imaged by the imaging means, and image signal intensity distribution data is generated by dividing the signal output from the imaging means into image areas with the light emission image area of the point light source as the basic unit, and the generated image signal intensity The distribution data is converted into flare intensity distribution data, flare correction data is calculated from the converted flare intensity distribution data and the illuminance distribution data of the reading surface detected by previously emitting the illumination means, and stored in the storage means,
An image reading apparatus that generates image signal data in which a flare component is corrected based on image signal data of a document read by emitting light from an illumination unit and flare correction data stored in a storage unit.   The image reading apparatus according to claim 10, wherein a plurality of flare correction data is stored in the storage unit for each specific area of the document.   The image reading apparatus according to claim 10, wherein a plurality of flare correction data are stored in the storage unit for each variable magnification when reading a document.   11. The image reading apparatus according to claim 10, wherein the arithmetic means calculates flare correction data corresponding to a magnification ratio when reading a document from flare correction data at the same magnification. In an illuminating unit that irradiates light on a reading surface of a document, an imaging unit that images the reading surface with light irradiated on the reading surface of the document, and an image reading apparatus that generates image signal data from a signal output from the imaging unit ,
Illuminance distribution data storage means, arithmetic processing means and flare intensity distribution data storage means,
The illuminance distribution data storage means stores the illuminance distribution data of the reading surface detected by emitting light from the illumination means in advance,
The arithmetic processing means is configured such that when a measurement original having a reading surface formed of a diffuse reflection surface and having a point light source is placed on the original placement surface and the point light source emits light, the light emitted from the point light source emits light on the reading surface. Light reflected from the entire surface is imaged by the imaging means, and image signal intensity distribution data is generated by dividing the signal output from the imaging means into image areas with the light emission image area of the point light source as the basic unit, and the generated image signal intensity The distribution data is converted into flare intensity distribution data, and the converted flare intensity distribution data is stored in the flare intensity distribution data storage means,
Image signal data subjected to flare correction is generated from image signal data of a document read by emitting light from the illumination unit, flare intensity distribution data stored in the flare intensity distribution data storage unit, and illuminance distribution data stored in the illuminance distribution data storage unit. An image reading apparatus.   15. The image reading apparatus according to claim 14, wherein said flare intensity distribution data storage means stores a plurality of flare intensity distribution data for each specific area of the document.   15. The image reading apparatus according to claim 14, wherein the flare intensity distribution data storage means stores a plurality of flare intensity distribution data for each variable magnification when reading an original.   An image forming apparatus comprising the image reading apparatus according to claim 10.

Images