JP5423267B2 - Image reading apparatus, image reading method, program, and recording medium - Google Patents

Description

  The present invention relates to an image reading apparatus that detects an abnormal image, an image reading method, a program, and a recording medium.

  An image reading apparatus such as a copying apparatus or a composite apparatus is provided with a light source that emits light for reading an original. As this light source, a linear light source that irradiates a continuous line of light on a manuscript such as a xenon (Xe) lamp or a cold cathode tube lamp has been used. However, it takes time for maintenance, has a relatively short life, and is inexpensive. Since it is expensive, the cost has been increased.

  Therefore, in recent years, instead of a linear light source such as the xenon (Xe) lamp, an LED (Light Emitting Diode) that is easy to maintain, has a long life, and is low in cost has been applied as a light source for reading a document. When using LED which is a point light emitting element as a light source, generally, a light source substrate on which LED elements are mounted in an array in the main scanning direction is used.

  However, when a light source in which LED elements are arranged in an array is used, as shown in FIG. 11, the halation is a phenomenon in which the light intensity increases at a position corresponding to the arrangement pitch of the LEDs, and the image is blown out in a dot shape. May occur. Halation is a phenomenon that tends to occur when a thick document is read.For example, when a book is opened as a document and placed on the contact glass, an area floating from the contact glass surface, such as a binding margin, is formed. It is likely to occur when reading as it is. Further, the halation phenomenon tends to be more prominent in a glossy document. That is, this halation phenomenon occurs when light regularly reflected by a curved portion near the binding margin is incident on the optical axis of the reading light and becomes reflected light having high intensity.

  In order to suppress the occurrence of halation as described above, a technique for blocking an optical path that causes halation has been proposed (for example, Patent Document 1). As another technique for suppressing the occurrence of halation, a technique has been proposed in which a diffuser plate is provided on the optical path from the LED to the original so that the light from the light source becomes uniform in the main scanning direction ( For example, Patent Document 2).

  However, in the technique described in Patent Document 1, halation is suppressed by blocking a part of the reading light from an optical path that causes halation. For this reason, there is a problem in that the amount of light applied to the document is reduced and efficiency is lowered, and the number of parts of the apparatus is increased, resulting in an increase in cost.

  In addition, the techniques described in Patent Document 1 and Patent Document 2 have a problem that halation cannot be detected when halation actually occurs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image reading apparatus, an image reading method, a program, and a recording medium that can accurately detect the occurrence of halation.

The image reading apparatus of the present invention are arranged in rows in the main scanning direction, a light source means comprising a plurality of point-like light-emitting element for irradiating reading light on a document, photoelectrically converts the reflected light of the reading light from the original and photoelectric conversion means for outputting a main scanning direction of the line image data, the halation detection means for detecting the position of the picture element to a predetermined threshold value higher than the signal level is detected in the output to line image data of the photoelectric conversion means When a storage means for storing the detection result of the line image data by the halation detection means comprises an image processing means for performing image processing on the image data, and the halation detection means, a plurality stored in said storage means halation generation interval of the position a high signal level is detected ones of the line image data and for each line based on the arrangement pitch of the point-like light emitting element Determining free, it is assumed that halation occurs obliquely in the entire image when it detects a high level signal at all positions in the detection results of the plurality of lines accumulated, the image processing means, wherein The pixel value of the image data in which halation is detected detected by the halation detecting means is corrected to a predetermined pixel value.

  According to the present invention, the occurrence of halation can be accurately detected.

1 is a block diagram illustrating a schematic functional configuration example of an image reading apparatus according to an embodiment. 1 is a diagram illustrating a schematic configuration example of an image reading apparatus according to an embodiment. 1 is a diagram illustrating a schematic configuration example of an image reading unit in an image reading apparatus according to an embodiment. It is a figure for demonstrating a document reading state. It is a figure which shows the output distribution example for 1 line of image data when halation generate | occur | produces in the main scanning direction. It is a schematic diagram which shows the example of image data when a halation generate | occur | produces in the diagonal direction of the main scanning direction. It is a figure which shows the output distribution example for 1 line of image data when a halation generate | occur | produces in the diagonal direction of the main scanning direction. It is a figure for demonstrating the example of a halation detection. 5 is a flowchart showing a flow of an example of a document reading operation of the image reading apparatus according to the present embodiment. 6 is a flowchart showing a flow of an example of a halation detection data acquisition operation of the image reading apparatus according to the present embodiment. It is a photograph for explaining halation.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiment, a scanner is described as an example of the image reading apparatus, but the present invention is not limited to this.

  FIG. 1 is a diagram illustrating a schematic functional configuration example of the image reading apparatus according to the present embodiment. As shown in FIG. 1, an image reading apparatus according to this embodiment includes an image reading unit 205, a CPU (Central Processing Unit) 101, a drive control unit 105, a motor 106, an AFE (Analog Front End) 109, an image processing unit, and the like. And a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The image reading unit 205 includes an LED 107 and a CCD (Charge Coupled Device) 108. The drive control unit 105 includes a CCD / AFE control unit 102, a motor control unit 103, an LED control unit 104, and the like. The image forming unit includes an image processing unit 110 and a halation detection unit 111. In this embodiment, an example in which the image processing unit includes the image processing unit 110 and the halation detection unit 111 will be described. However, the halation detection unit 111 and the image forming unit 110 may be provided independently. is there.

  The CPU 101 controls each unit of the image reading apparatus by using the RAM as a work memory based on a program stored in the ROM. That is, the CPU 101 executes basic processing as the image reading device and executes image reading processing in the present embodiment.

  That is, the image reading apparatus includes ROM, EEPROM (Electrically Erasable and Programmable Read Only Memory), EPROM, flash memory, flexible disk, CD-ROM (Compact Disc Read Only Memory), CD-RW (Compact Disc Rewritable), DVD ( An image reading program for executing the image reading method according to the present embodiment recorded on a computer-readable recording medium such as a digital video disk (SD), a secure digital (SD) card, or an MO (Magneto-Optical Disc) is read. By introducing it into a ROM, hard disk or the like (not shown), it is detected whether halation has occurred in read image data, which will be described later. When halation occurs, the image reading apparatus executes an image reading method for correcting the read image data. This image reading program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark) or an object-oriented programming language, and is stored in the recording medium. Can be distributed.

  As described above, the image reading unit 205 irradiates the original or the white reference plate with the reading light emitted from the LED 107 through the contact glass or the ADF glass. The original introduces the reflected light reflected by the white reference plate into the CCD 108. The CCD 108 photoelectrically converts the introduced reflected light and outputs an analog image signal to the AFE 109. The AFE 109 converts analog image data input from the CCD 106 of the image reading unit 205 into digital image data. Also, dark offset level adjustment and bright output adjustment are performed.

  The halation detection unit 111 includes, for example, a comparison unit, a determination unit, a light emitting element abnormality detection unit, and a storage unit. The halation detection unit 111 operates under the control of the CPU 101 to detect halation occurrence from the digital image data output from the AFE 109, and the positional relationship between the plurality of LEDs 107 provided as light sources in the main scanning direction. Then, a failure detection process for detecting a failure of the LED 107 based on the relationship between the pixel positions where the output level locally increases due to halation is performed, and image data is output to the image processing unit 110. Further, the halation detection unit 111 stores halation detection information for each line in the halation detection processing in the storage unit.

  The image processing unit 110 including a correction unit operates under the control of the CPU 101 and performs various image processing such as halation correction, dark output correction, shading correction, and γ correction on the digital image data digitally converted by the AFE 109. Apply. Note that the image processing performed by the image processing unit 110 is not limited to the above-described image processing, and known image processing can be applied. After performing image processing, the image processing unit 110 outputs to a subsequent processing unit and corrects all pixels of image data in which halation occurs to a predetermined pixel value.

  The CCD / AFE control unit 102 outputs drive signals to the CCD 108 and the AFE 107 under the control of the CPU 101 to control the operations of the CCD 108 and the AFE 107. The motor control unit 103 controls driving of the motor 106. The motor 106 includes a motor for moving the image reading unit 205 in the main scanning direction, and is a generic name for the motor. The LED control unit 104 outputs an LED control signal to the LED 107 under the control of the CPU 101 and controls the lighting of the LED 107.

  FIG. 2 shows a schematic configuration example of the image reading apparatus according to the present embodiment. As shown in FIG. 2, the image reading apparatus according to this embodiment includes a main body housing 201, an ADF (Auto Document Feeder) 202, a pressure plate 203, a document reading table 204, and an image reading unit 205. Yes. Note that the ADF 202 is not necessarily provided.

  A document reading table 204 is provided on the upper portion of the main body casing 201. The document reading table 204 is provided with a contact glass which is a transparent document table. A pressure plate 203 that can be opened and closed is provided on the upper part of the document reading table 204. The pressure plate 203 presses the document set on the document reading table 204 so as to be in close contact with the contact glass of the document reading table 204.

  In the example shown in FIG. 2, an ADF 202 is provided on the upper left side of the main body casing 201. An image reading unit 205 is provided below the document reading table 204 inside the main body casing 201. The image reading unit 205 is provided so as to be movable in the left-right direction (sub-scanning direction) indicated by an arrow in the drawing as the scanning direction.

  Although not shown, the ADF 202 includes a document table on which a plurality of documents are placed, a document presence / absence detection sensor that detects the presence / absence of a document on the document table, a document transport mechanism, a paper discharge tray, and the like. The ADF 202 conveys a plurality of documents on the document table one by one to the reading position of the document reading table 204 by the document conveyance mechanism, and discharges the document that has been read to the discharge tray. The ADF 202 is integrated with the pressure plate 203, and when the pressure plate 202 is opened, the ADF 202 is also opened and closed together. The document reading table 203 is provided with a white reference plate for shading correction and an ADF glass serving as a transparent document table on the ADF 202 side of the contact glass. Details will be described later with reference to FIG.

  FIG. 3 shows a schematic configuration example of the image reading unit 205 in the image reading apparatus according to the present embodiment. As shown in FIG. 3, the image reading unit 205 includes an LED 107, a CCD 108, a lens 302, an LED substrate 303, a mirror 305, a unit case 306, an SBU (Sensor Board Unit) 307, and the like. Transparent glass is attached to the upper surface of the unit case 306, that is, the surface of the document reading table.

  The LED 107 is mounted on the LED substrate 303. In the present embodiment, an example in which a plurality of LEDs 107 are mounted in a line on the LED substrate 303 is shown. The LED 107 is a light source that, when energized, irradiates a document with a light amount corresponding to the current value. The light emitted from the LED 107 is reflected in the direction of the document reading table through the transparent glass by the reflecting plate, and is irradiated to the document through the contact glass 310 or the ADF glass 308. The light irradiated on the original is reflected by the original, reflected by the mirror 305 toward the lens 302, and condensed on the CCD 108 by the lens 302. The light emitted from the LED 107 is applied to the white reference plate 309, and the light reflected by the white reference plate 309 is reflected in the direction of the lens 302 by the mirror 305 and condensed on the CCD 108 by the lens 302. The CCD 108 which is a photoelectric conversion means photoelectrically converts incident light and outputs an analog image signal.

  Next, an example of an image reading operation of the image reading apparatus according to the present embodiment will be described.

  The image reading apparatus according to this embodiment irradiates a document with light from a plurality of LEDs 107 arranged in a line, and photoelectrically converts the reflected light to read a document image. Then, whether or not halation has occurred in the read document image data is detected on a line basis, and if halation has occurred, the image data is corrected.

  That is, in the ADF reading mode in which the image reading apparatus reads an image of a document using the ADF 202, when a plurality of documents are set on the document table of the ADF 202, the LED 107 is first turned on under the control of the LED control unit 104. After reading the white reference plate 309, the motor 106 is driven by the motor control unit 103. Next, the image reading apparatus moves the image reading unit 205 to the ADF reading position below the ADF glass 308, drives the ADF motor, and sets a plurality of documents set on the document table of the ADF 202 to 1 Each sheet is separated and conveyed to the reading position of the ADF glass 308. At this time, the document is conveyed at a constant speed, and the image reading unit 205 remains stopped. The image reading unit 205 irradiates the document conveyed from the LED 107 with light for reading, reflects the reflected light reflected by the document by the mirror 305, enters the CCD 108 through the lens 302, and performs photoelectric conversion by the CCD 108. Scan the original image.

  Further, in the book mode in which the image reading apparatus reads the image data of the original fixedly set on the contact glass 310, when the original is set on the contact glass 310 by opening the pressure plate 203, the LED control unit 104 The LED 107 is turned on under control, and the white reference plate 309 is first read to obtain reference data for shading correction. Thereafter, the motor 106 is driven, and the image reading unit 205 is moved in the scanning direction (sub-scanning direction) to read the image of the document on the contact glass 310. At this time, the image reading apparatus moves the image reading unit 205 over the scan area shown in FIG. 2 and reads the image of the document on the contact glass 310.

  The image reading apparatus outputs the analog image signal of the original image read by the image reading unit 205 as described above from the CCD 108 to the AFE 109. The AFE 109 digitally converts the input analog image signal and outputs it to the halation detection unit 111.

  Here, in the book mode, as shown in FIG. 4A, when the original set on the contact glass 310 is a flat original, the flat original is in close contact with the contact glass 310. The image of the flat original can be read appropriately by 205. On the other hand, as shown in FIG. 4B, when the original set on the contact glass 310 is a three-dimensional original, that is, for example, when an open book is set on the contact glass 310, a binding margin portion, etc. In the case of a document having a part that floats from the surface of the contact glass 310 as described above, the reading surface of the three-dimensional document is not in close contact with the contact glass 310. Therefore, specular reflection of the reading light occurs at a portion floating from the surface of the contact glass 310 such as a binding margin, and the light irradiated to the three-dimensional original is directly incident on the optical axis of the reading light as a strong specular reflection component. The image read by the CCD 108 becomes an image in which the light intensity is locally increased at a position corresponding to the arrangement pitch of the LEDs 107 which are point light emitting elements.

  As shown in FIG. 5, for example, the image data of the image data when the halation as described above occurs has a high signal level at predetermined intervals in one line in the main scanning direction. Such halation image data is generated because incident light having a high light intensity is incident on the CCD 108 at a pixel interval corresponding to the arrangement pitch of the LEDs 107 as described above. When such an LED 107 is used as a reading light source, the light intensity increases in dots in the main scanning direction, resulting in an abnormal image in which the images are overexposed. That is, the halation detection unit 111 determines that halation has occurred if the predetermined interval matches the arrangement pitch of the LEDs 107.

  Further, as shown in FIG. 5, the image data when halation occurs in one line in the main scanning direction has a high signal level in the line portion where halation occurs in the sub-scanning direction, and halation occurs. The signal level decreases as the distance from the line portion increases.

  Here, the case where halation occurs in one line in the main scanning direction is described as an example as shown in FIG. 5, but the halation does not necessarily occur in one line in the main scanning direction. For example, it is conceivable that halation occurs in an oblique direction of the main scanning direction. FIG. 6 shows a schematic diagram of image data when halation occurs in an oblique direction in the main scanning direction. The occurrence of halation as shown in FIG. 6 occurs, for example, when the degree of floating of the document to be read from the contact glass surface is different between the back side and the near side of the image reading apparatus. For example, this occurs when the pressure plate 203 is closed only halfway when reading a book or the like, and only the back side of the image reading apparatus at the binding margin portion of the book is pressed by the pressure plate 203.

  FIG. 7 shows an output distribution example for one line of image data when halation occurs in an oblique direction in the main scanning direction as described above. Line a, line b, and line c indicate output distributions for one line of image data of different lines. As shown in FIG. 7, when halation occurs in an oblique direction in the main scanning direction, unlike the case where halation occurs in one line in the main scanning direction as shown in FIG. The occurrence of halation cannot be detected from the output distribution for one line of data. Therefore, in this embodiment, the halation detection unit 111 stores the detection results from line a to line c, and integrates the detection results from line a to line c to determine whether halation has occurred.

  In the present embodiment, an example in which the presence or absence of halation is determined by integrating the three lines a to c will be described. However, the present invention is not limited to this. The number of lines used for detection by the halation detection unit 111 can be changed as appropriate, and a setting input can be received from the user via the operation unit. Also, which line's detection result is stored can be changed as appropriate, and a setting input can be received from the user via the operation unit.

  An example of detection results in line a to line c stored in the storage means is shown in FIG. In the example shown in FIG. 8, a high signal level is detected at the positions (1) to (3) in the line a. In line b, a high signal level is detected at the positions (4) to (7). In line c, a high signal level is detected at the positions (8) to (14). As described above, it is determined that halation has occurred when a high-level signal is detected even once at all positions upon completion of document scanning.

The results described above are shown in FIG. In FIG. 8 , a circle is indicated at a position where the halation detection unit 111 has detected a high level signal. As shown in FIG. 8 , in the present embodiment, the detection result of the line a is shown for the line b, and the detection result of the line a and the line b is shown for the line c. Since the circles are indicated at all positions after the scan is completed, it can be determined that the halation is occurring obliquely.

  In the present embodiment, an example is described in which it is determined that halation has occurred when all the accumulated results at all points are ◯ at the time of completion of document scanning. For example, if there is “80% or more, halation has occurred” Or “determine that halation has occurred if 10 or more points out of 14 points”. In that case, it is also possible to detect halation that occurs when some of the LEDs are not lit due to failure of the LEDs.

  6 to 8 will be described by taking as an example the case where halation occurs in the upward direction in the drawing, but the present invention is not limited to this. That is, the image reading apparatus according to the present embodiment can detect halation occurring in any direction.

  Although the halation is likely to occur when the original on the contact glass 310 is read as described above, it may also occur when the original conveyed on the ADF glass 308 is read. Therefore, the processing for suppressing the influence of halation described in the present embodiment is applied not only when reading a document on the contact glass 310 but also when reading a document conveyed on the ADF glass 308. Can do.

  Therefore, the image reading apparatus according to the present embodiment performs necessary image processing on the image data digitally converted by the AFE 109 in the image processing unit 110. Before the image processing by the image processing unit 110, the AFE 109 performs digital conversion. In the image data, the halation detection unit 111 detects whether or not halation has occurred, and if halation has occurred, the image processing unit 110 performs halation correction processing and then performs normal image processing.

  FIG. 9 shows a flow of an example of an original reading operation of the image reading apparatus according to the present embodiment. As shown in FIG. 9, when reading of a document is started (step S901), the CPU 101 inputs digital image data for one line for halation detection from the image reading unit 205 to the halation detecting unit 111 via the AFE 109 (step S901). Step S902). The halation detection unit 111 stores the halation detection data acquired in step S902 in a storage unit included in the halation detection unit 111. Next, the CPU 101 determines whether the image reading unit 205 has read the document to the end of the document to be read (step S903). If the document has not been read to the end (step S903 / NO), the process proceeds to step S902, and the above process is repeated until the document is read to the end.

  On the other hand, if it is determined that the end of the document has been read (step S903 / YES), the halation detection unit 111 determines whether or not halation has occurred based on the halation detection data acquired in step S902 (step S902). S904).

  When the occurrence of halation is detected by the halation detection unit 111 (step S904 / YES), the image processing unit 110 performs image processing including halation correction on the image data (step S905). On the other hand, when the occurrence of halation is not detected by the halation detection unit 111 (step S904 / NO), the image processing unit 110 performs other image processing on the image data without performing halation correction (step S906). ). Here, in the halation correction, for example, the brightness of all the pixels of a plurality of line image data in which halation occurs is calculated, and only the brightness of all the pixels of the line image data is corrected to a predetermined brightness based on the brightness calculation result. This can be done.

  FIG. 10 shows a flow of an operation example of obtaining data for detecting halation by the halation detecting unit 111 according to this embodiment. Hereinafter, a flow of an operation example of obtaining data for detecting halation in the image reading apparatus according to the present embodiment, that is, the processing in step S902 will be described.

  First, the halation detection unit 111 acquires digital image data for one line for halation detection from the image reading unit 205 via the AFE 109 (step S1001). Next, the halation detection unit 111 determines whether or not the acquired image data includes an output with a high signal level equal to or higher than a predetermined threshold (step S1002). If the acquired image data does not output a signal level higher than a predetermined threshold (step S1002 / NO), the halation detection unit 111 ends the operation.

  On the other hand, if the acquired image data includes a high signal level output that is equal to or higher than the predetermined threshold (step S1002 / YES), the halation detection unit 111 detects the position of the pixel where the high signal level is detected (step S1003). ). Then, it is determined whether or not the pixel position detected in step S1003 matches the pitch of the LED 107 (step S1004). If the pixel position detected in step S1003 does not match the pitch of the LED 107 (step S1004 / NO), the halation detection unit 111 ends the operation.

  On the other hand, when the position of the pixel detected in step S1003 matches the pitch of the LED 107 (step S1004 / YES), the halation detection unit 111 stores a pixel position having an output with a signal level higher than the threshold in the storage unit. (Step S1005).

  In the halation detection unit 111, the above-described processing is repeated until the end of the document. Then, the halation detection unit 111 performs the halation detection in step S904 based on the information on the pixel position with the output of the signal level higher than the threshold stored in the storage unit by the above-described processing.

  According to the present embodiment, the presence or absence of halation can be detected appropriately and easily, and a halation image that is overexposed when using a point light source in which LEDs are arranged in a line can be corrected. In addition, a high-quality read image can be obtained. In addition, it is possible to correct only the brightness of all the pixels of the image data of the line in which halation occurs to an appropriate brightness, and it is possible to appropriately remove halation.

  Furthermore, it is possible to accurately detect various halation such as halation occurring obliquely, as well as halation occurring in one line of the image. This makes it possible to obtain a higher quality read image.

  Note that a program for the CPU to execute the processing shown in the flowcharts of the respective drawings constitutes a program according to the present invention. As a computer-readable recording medium for recording the program, a semiconductor storage unit, an optical and / or magnetic storage unit, or the like can be used. By using such a program and recording medium in a system having a different configuration from the above-described embodiments and causing the CPU of the system to execute the program, substantially the same effect as the present invention can be obtained. .

  Although specifically described above based on the preferred embodiments, the present invention is not limited to the above-described image reading apparatus, image reading method, program, and recording medium, and can be variously modified without departing from the scope of the invention. It goes without saying that.

101 CPU
102 CCD / AFE control unit 103 Motor control unit 104 LED control unit 105 Drive control unit 106 Motor 107 LED
108 CCD
109 AFE
DESCRIPTION OF SYMBOLS 110 Image processing part 111 Halation detection part 201 Image reader main body housing | casing 202 ADF
203 Pressure Plate 204 Document Reading Table 205 Image Reading Unit 302 Lens 303 LED Board 305 Mirror 306 Unit Case 307 SBU
308 ADF glass 309 White reference plate 310 Contact glass

JP 2007-212949 A JP 2008-124881 A

Claims (12)

Light source means arranged in a row in the main scanning direction and containing a plurality of point light emitting elements for irradiating a document with reading light;
Photoelectric conversion means for photoelectrically converting reflected light of reading light from the original and outputting line image data in the main scanning direction;
A halation detection means for detecting the position of a picture element output predetermined threshold higher than the signal level at the line image data is detected in the photoelectric conversion means,
Storage means for storing the detection result of the line image data by the halation detection means;
Image processing means for performing image processing on the image data,
Whether the halation detection means generates halation for each line based on the interval between positions where a high signal level is detected among the plurality of line image data stored in the storage means and the arrangement pitch of the point light emitting elements. In the accumulation of detection results in a plurality of lines, if high level signals are detected at all positions, it is assumed that halation occurs diagonally in the entire image ,
The image reading device, wherein the image processing unit corrects a pixel value of image data in which halation is detected, which is detected by the halation detection unit, to a predetermined pixel value.   The image reading apparatus according to claim 1, further comprising an operation unit that receives an input for setting the threshold value.   The image reading apparatus according to claim 1, wherein the point light emitting element is an LED. The image reading apparatus according to claim 2 , wherein the halation detection unit determines that halation has occurred when a pixel value equal to or greater than the predetermined threshold is detected at a predetermined ratio or more.   The image reading apparatus according to claim 4, wherein the operation unit receives a setting input of the predetermined value. An irradiation step of irradiating the original with reading light by light source means arranged in a row in the main scanning direction and containing a plurality of point light emitting elements;
A photoelectric conversion step of photoelectrically converting reflected light of the reading light from the original and outputting line image data in the main scanning direction;
A detection step of detecting a position of a picture element of a predetermined threshold value higher than the signal level is detected in the output line image data by said photoelectric conversion step,
A storage step of storing the detection result of the line image data by the detection step;
Based on the interval between positions where a high signal level is detected from the plurality of line image data stored in the storing step and the arrangement pitch of the point light emitting elements, the presence / absence of halation occurrence for each line is determined, In the accumulation of detection results in the line, when a high level signal is detected at all positions, a halation detection step in which halation occurs diagonally in the entire image ,
An image processing method comprising: an image processing step of correcting a pixel value of image data in which halation is detected detected by the halation detection step to a predetermined pixel value.   The image reading method according to claim 6, further comprising a setting step for receiving a setting input of the threshold value.   The image reading method according to claim 6, wherein the irradiation step irradiates a document with reading light by a plurality of LEDs. The said halation detection process judges that the halation has generate | occur | produced when the pixel value more than the said predetermined threshold value is detected more than a predetermined ratio , The one of Claim 6-8 characterized by the above-mentioned. Image reading method.   The image reading method according to claim 9, further comprising a predetermined value setting step for receiving a setting input of the predetermined value. A process of irradiating the original with reading light by light source means arranged in a row in the main scanning direction and containing a plurality of point light emitting elements;
A process of photoelectrically converting reflected light of reading light from the original and outputting line image data in the main scanning direction;
Processing for detecting the position of a pixel in which a high signal level equal to or higher than a predetermined threshold is detected in the output line image data;
Processing for storing the detection result of the line image data;
Detection of occurrence of halation for each line based on the interval between positions where a high signal level is detected from the stored plurality of line image data and the arrangement pitch of the point light emitting elements, and detection in a plurality of lines In the accumulation of results, when high level signals are detected at all positions, it is assumed that halation occurs diagonally ;
A program for causing a computer to execute processing for correcting pixel values of detected image data in which halation has occurred to predetermined pixel values.   The computer-readable recording medium which recorded the program of Claim 11.