JP5045414B2 - Image reading apparatus and digital multifunction machine - Google Patents

Description

  The present invention relates to an image reading apparatus and a digital multi-function peripheral, and more particularly to an image reading apparatus and a digital multi-function peripheral that detect and correct defective pixels.

  The image reading device reads a document placed on a document table by driving a reading head equipped with a line sensor, and generates image data. FIG. 1 is a block diagram for explaining the structure of a general line sensor LS.

  As shown in FIG. 1, the line sensor LS includes a plurality of photodiodes PD [0] to PD [2 (N−1) +1] that are pixel sensors arranged in a line, and a plurality of output registers Hreg [ 0] to Hreg [N-1]. For example, in FIG. 1, when 2400 photodiodes are provided as pixel sensors, 1200 output registers are provided, and N = 1200.

  The photodiodes PD [0] to PD [2 (N−1) +1] are pixel sensors for converting an optical signal that is image information into an electrical signal. An electric signal, which is image information generated by the photodiodes PD [0] to PD [2 (N−1) +1], is output to the line sensor via the output registers Hreg [0] to Hreg [N−1]. Output from LS. Specifically, the electrical signals output from the output registers Hreg [0] to Hreg [N-1] are converted into digital signals by an analog / digital converter and output from the semiconductor chip as digital data. Then, image data composed of digital data is generated.

  As can be seen from FIG. 1, the number of output registers Hreg [0] to Hreg [N−1] is ½ of the number of photodiodes PD [0] to PD [2 (N−1) +1]. . That is, two photodiodes PD [0] to PD [2 (N−1) +1] are provided for one output register output register Hreg [0] to Hreg [N−1]. The line sensor LS having such a configuration is provided with two output modes of normal output and block output.

  In the normal output, as shown in FIG. 2, for example, the image information of the pixel C [0] is constituted by the sum of the outputs of the photodiode PD [0] and the photodiode PD [1], and the pixel C [1] ] Is constituted by the sum of the outputs of the photodiode PD [2] and the photodiode PD [3]. Such composition of image information is performed by the output registers Hreg [0] to Hreg [N−1]. That is, the image information of the pixel C [0] is obtained by adding the charge generated by the photodiode PD [0] and the charge generated by the photodiode PD [1] to the output register Hreg [0]. The Since the summed electric charge is taken as an electric signal by an analog / digital converter and converted into a digital signal, the sum of the outputs of the photodiode PD [0] and the photodiode PD [1] is obtained as image information. It is.

  In the case of the line sensor LS of FIG. 1, the resolution of the image data generated with the image information obtained by such an operation is 1200 dpi. In order to obtain image data with a lower resolution, necessary processing is appropriately performed after conversion to a digital signal.

  On the other hand, if block output is used for the output mode, image data with a resolution of 2400 dpi can be obtained using this line sensor LS, for example. FIG. 3 is a block diagram for explaining the mechanism of this block output.

  As shown in FIG. 3, in the block 1 that is the first output, charges generated by the even-numbered photodiodes PD [0], [2]... [2 (N−1)] are transferred to the output register Hreg. [0] to Hreg [N−1], the electrical signals output from the output registers Hreg [0] to Hreg [N−1] are converted into digital signals, and even-numbered pixels C [0] , [2]... [2 (N−1)] image information is generated.

  After the output of the first block 1 is completed, the second output is generated by the odd-numbered photodiodes PD [1], [3]... [2 (N−1) +1] in the block 2 which is the second output. The electric charges are output to the output registers Hreg [0] to Hreg [N−1], and the electric signals output from the output registers Hreg [0] to Hreg [N−1] are converted into digital signals to generate odd-numbered signals. Image information of the pixels C [1], [3]... [2 (N−1) +1] is generated.

  Thus, in the block output, the output registers Hreg [0] to Hreg [N−1] are provided with only half the number of diodes PD [0] to PD [2 (N−1) +1]. The image information generated by the photodiodes PD [0] to PD [2 (N−1) +1] is output in two divided portions.

  These two output modes, normal output and block output, are controlled by the image reading apparatus by switching the reading resolution designated by the user.

  In this way, with respect to the image information obtained by the normal output or the block output, there may be some defects in the photodiodes PD [0] to PD [2 (N−1) +1]. In general, it is determined whether or not a pixel is a defective pixel with respect to image information of the pixel, and if the pixel is a defective pixel, correction is performed (for example, Japanese Patent Laid-Open No. 2002-354262, JP, 2003-101737, A).

  FIG. 4 is a diagram for explaining processing for detecting a pixel defect in image data obtained by normal output and correcting it. As shown in FIG. 4, when it is determined whether or not the nth pixel C [n] is a defective pixel and the correction is made, the image information of the pixel [n-2] adjacent to the two pixels and the pixel [n + 2] These determinations and processing are performed based on the image information.

  However, in the conventional technique, the same process is performed on the image data obtained by the block output, and therefore, a process of detecting a pixel defect and correcting it is performed by the pixel [n-4] adjacent to the four pixels. Based on the image information of the pixel and the image information of the pixel [n + 4]. That is, as illustrated in FIG. 5, when it is determined whether or not the 2n-th pixel C [2n] in the block 1 is a defective pixel and the correction is performed, the pixel [2n−4] adjacent to the two pixels in the block 1 is corrected. ] And the determination and processing are performed based on the image information of the pixel [2n + 4]. Further, when it is determined whether or not the 2n + 1-th pixel C [2n + 1] in the block 2 is a defective pixel and the correction is made, the image information and the pixel [2n-3] adjacent to the two pixels in the block 2 are corrected. These determinations and processing are performed based on the image information of 2n + 5]. For this reason, in an actual image, pixel defects are detected and corrected using image information of pixels adjacent to the four pixels.

However, if pixel defects are detected and corrected based on image information of pixels adjacent to the four pixels, it may not always be appropriate to detect or correct pixel defects.
Japanese Patent Laid-Open No. 2002-354262 JP 2003-101737 A

  Therefore, the present invention has been made in view of the above problems, and provides an image reading apparatus and a digital multi-function peripheral that can detect and correct appropriate pixel defects even when a block output is made from a line sensor. For the purpose.

In order to solve the above problems, an image reading apparatus according to the present invention includes:
A line sensor having a plurality of pixel sensors arranged in a line, wherein two pixel sensors are assigned to one output register;
As an output mode for outputting image information from the pixel sensor of the line sensor, after outputting image information of one pixel sensor assigned to one output register as first block image information, Block output executing means for outputting image information as second block image information, executing block output;
In the first block image information output by the block output execution unit, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined by the first block of the pixel sensor that is the determination target. First determination means for determining based on two pieces of image information on both sides in the image information;
The image information of the pixel sensor in the first block image information determined to be a defective pixel by the first determination means is adjacent to the first block image information of the pixel sensor determined to be the defective pixel. First correcting means for correcting based on two pieces of image information;
In the second block image information output by the block output execution means, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined by the second block of the pixel sensor that is the determination target. Second determination means for determining based on two pieces of image information on both sides in the image information;
The image information of the pixel sensor in the second block image information determined to be a defective pixel by the second determination means is adjacent to the second block image information of the pixel sensor determined to be the defective pixel. Second correction means for correcting based on two pieces of image information;
It is characterized by providing.

In this case, as an output mode for outputting the image information from the pixel sensor of the line sensor, the image information of the two pixel sensors assigned to one output register is added up and the normal output which is one image information Normal output executing means for executing normal output output from the output register as image information;
In the normal output image information output by the normal output execution means, whether or not the image information of the pixel sensor that is the determination target is a defective pixel, the normal output image information of the pixel sensor that is the determination target Third determination means for determining based on two pieces of image information adjacent to the left and right in
The image information of the pixel sensor in the normal output image information determined to be a defective pixel by the third determination means is adjacent to the left and right in the normal output image information of the pixel sensor determined to be the defective pixel. Third correcting means for correcting based on the two pieces of image information;
May be further provided.

  In this case, switching means for switching and executing the block output execution means and the normal output execution means may be further provided.

An image reading apparatus control method according to the present invention includes:
A control method of an image reading apparatus having a line sensor, wherein the pixel sensor has a plurality of pixel sensors arranged in a line and two pixel sensors are assigned to one output register,
As an output mode for outputting image information from the pixel sensor of the line sensor, after outputting image information of one pixel sensor assigned to one output register as first block image information, Outputting image information as second block image information, performing block output;
In the output first block image information, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is indicated on both sides of the first block image information of the pixel sensor that is the determination target. Determining based on two pieces of image information;
The image information of the pixel sensor in the first block image information determined to be the defective pixel is based on the two pieces of image information adjacent to each other in the first block image information of the pixel sensor determined to be the defective pixel. And correcting the process,
In the output second block image information, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined on both sides of the second block image information of the pixel sensor that is the determination target. Determining based on two pieces of image information;
The image information of the pixel sensor in the second block image information determined to be the defective pixel is based on the two pieces of image information on both sides in the second block image information of the pixel sensor determined to be the defective pixel. And correcting the process,
It is characterized by providing.

  Note that the present invention can be realized as a digital multi-function peripheral including the image reading apparatus as described above, and can also be realized as a control method for such a digital multi-function peripheral.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below do not limit the technical scope of the present invention. In the following embodiments, the case where the present invention is applied to a scanner unit that is an image reading apparatus of a digital multi-function peripheral will be described as an example. However, the present invention can be applied to all kinds of image reading apparatuses.

  FIG. 6 is a block diagram illustrating an example of an internal configuration of the digital multifunction peripheral according to the present embodiment. As shown in FIG. 6, the digital multifunction peripheral 10 mainly includes a CPU (Central Processing Unit) 20, a RAM (Random Access Memory) 22, a ROM (Read Only Memory) 24, a printer unit 26, and a scanner unit. 28 and a hard disk drive 30, which are appropriately connected via an internal bus 40, an interface, and the like.

  The CPU 20 is a control unit that performs overall control of the digital multi-function peripheral 10 by software. The CPU 20 reads out a program necessary for controlling the digital multifunction peripheral 10 from the ROM 24 or the hard disk drive 30 and executes it. In executing these programs, the CPU 20 temporarily stores data in the RAM 22 or the hard disk drive 30 as appropriate.

  The printer unit 26 is configured by an ink jet type or laser beam type printer engine. The scanner unit 28 corresponds to the image reading apparatus in the present embodiment, and is an apparatus for reading a set original as image data. The hard disk drive 30 is an example of an auxiliary storage device, and can store data in a nonvolatile manner.

  FIG. 7 is a block diagram illustrating an example of the internal configuration of the scanner unit 28 of FIG. As shown in FIG. 7, the scanner unit 28 according to the present embodiment mainly includes a control unit 50, a document table 52, a reading head 54, and an ADF (Auto Document Feeder) 56. .

  The control unit 50 is a unit for controlling the scanner unit 28. Specifically, control for moving the reading head 54 and control for driving / stopping the ADF 56 are performed. In the present embodiment, the control unit 50 is configured by hardware such as an ASIC. However, an independent CPU may be provided in the control unit 50, and the scanner unit 28 may be controlled by software using this CPU.

  The ADF 56 constitutes an automatic document feeder in the present embodiment, and documents that the user wants to read continuously as image data are set in a bundle. The ADF 56 sends out the set originals one by one to the original table 52. The document sent to the document table 52 and placed at a predetermined position is read as image data by the reading head 54. In the present embodiment, the reading head 54 is provided with the line sensor LS shown in FIG. 1, and the reading head 54 moves from the beginning to the end of the document, so that one reading unit 54 corresponding to one document. Image data is acquired.

  The image data read from the reading head 54 is temporarily stored in, for example, a storage device provided in the control unit 50, and the image data stored in the storage device is appropriately transferred to the RAM 22 or the hard disk drive 30. .

  Next, pixel defect correction processing according to the present embodiment will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of pixel defect correction processing executed by the digital multifunction peripheral 10 according to the present embodiment. The pixel defect correction processing is realized by the CPU 20 reading and executing a pixel defect correction processing program stored in the ROM 24. The pixel defect correction process is a process that is automatically started when the digital multifunction peripheral 10 acquires image information from the scanner unit 28.

  In this pixel defect correction process, first, the digital multi-function peripheral 10 determines whether or not the output mode from the line sensor LS is a block output (step S10). In the present embodiment, since the line sensor LS has the configuration shown in FIG. 1, the output mode from the line sensor LS is a block output or a normal output depending on whether the resolution of the image data is 2400 dpi. Can be determined. Alternatively, since the output mode is switched by the digital multi-function peripheral 10, the CPU 20 or the control unit 50 that has switched the output mode makes a determination by storing the switching setting in a register or the like. You can also.

  When it is determined that the output mode from the line sensor LS is not a block output (step S10: NO), that is, when it is determined that the output is a normal output, the digital multi-function peripheral 10 is the n-th target. With reference to the image information of the pixel [n−2] adjacent to the pixel C [n] and the image information of the pixel [n + 2], it is determined whether or not the pixel C [n] is a pixel defect (step). S12). That is, as described using FIG. 4, in the direction in which the photodiodes PD of the line sensor LS are arranged, based on the image information of the two pixels on the left and right next to the pixel to be determined, It is determined whether the pixel to be determined is a defective pixel.

  Various determination methods can be considered. For example, the image information of the pixel C [n] is based on the image information of the pixel [n−2] adjacent to the two pixels and the image information of the pixel [n + 2]. An upper limit value and a lower limit value of possible values are calculated, and when the value of the image information of the pixel C [n] is not between these upper limit value and lower limit value, it is determined that the pixel is defective. it can.

  As a result of this determination, when it is determined that the pixel to be determined is a pixel defect (step S14: YES), the digital multi-function peripheral 10 sets 2 of the target n-th pixel C [n]. The image information of the pixel C [n] is corrected with reference to the image information of the pixel [n−2] adjacent to the pixel and the image information of the pixel [n + 2] (step S16).

  Various correction methods can be considered. For example, an intermediate value between the value of the image information of the left and right pixels [n−2] adjacent to the two pixels and the value of the image information of the pixel [n + 2] is calculated. The intermediate value can be the value of the image information of the pixel C [n].

  After the process of step S16, or when it is determined that the pixel to be determined is not a pixel defect in step S14 described above (step S14: NO), the digital multi-function peripheral 10 acquires an image acquired from the line sensor LS. It is determined whether or not this processing has been performed for all information (step S18). That is, it is determined whether pixel defect determination and correction processing has been performed for pixel C [0] to pixel C [2 (N−1) +1].

  If it is determined that this process has not been performed for all pixels (step S18: NO), the digital multifunction peripheral 10 moves the determination target pixel to the next pixel and repeats the above-described step S12. Specifically, by adding 1 to n, the determination target pixel is shifted to the right by one, and the above-described step S12 is repeated.

  On the other hand, if it is determined that this process has been performed for all the pixels (step S18: YES), the digital multifunction peripheral 10 ends this pixel defect correction process.

  On the other hand, if it is determined in step S10 described above that the output mode from the line sensor LS is block output (step S10: YES), the digital multi-function peripheral 10 will block as shown in FIG. Whether the pixel C [2n] is a pixel defect with reference to the pixel [2n-2] and the pixel [2n + 2] that are adjacent to the 2n-th pixel C [2n] that is the target in 1 The pixel C [2n + 1] is a pixel defect with reference to the pixel [2n-1] and the pixel [2n + 3] that are adjacent to the 2n + 1-th pixel C [2n + 1] that is the target in the block 2. It is determined whether or not there is (step S22).

  That is, first, for the block 1, in the direction in which the photodiodes PD of the line sensor LS are arranged, the pixel [2n-2] and the pixel [2n + 2] on both the left and right sides of the pixel [2n] to be determined Based on the image information, it is determined whether the determination target pixel [2n] is a defective pixel. This is because in the case of block output, the two pixels adjacent to both sides of the pixel to be determined become two adjacent pixels in the physical arrangement of the line sensor LS.

  For block 2, in the direction in which the photodiodes PD of the line sensor LS are arranged, an image of the pixel [2n−1] and the pixel [2n + 3] immediately adjacent to the pixel [2n + 1] to be determined Based on the information, it is determined whether the determination target pixel [2n + 1] is a defective pixel. This is because in the case of block output, the two pixels adjacent to both sides of the pixel to be determined become two adjacent pixels in the physical arrangement of the line sensor LS.

  It is the same as step S12 described above that various determination methods can be considered in step S22.

  As a result of this determination, when it is determined that the pixel to be determined is a pixel defect (step S24: YES), the digital multi-function peripheral 10 determines that the 2n-th pixel C [2n] that is the correction target. The image information of the pixel C [2n] is corrected by referring to the image information of the pixel [2n-2] adjacent to the pixel and the image information of the pixel [2n + 2], and the 2n + 1th pixel to be corrected The pixel C [2n + 1] is corrected with reference to the image information of the pixel [2n-1] adjacent to the pixel of C [2n + 1] and the image information of the pixel [2n + 3] (step S26).

  That is, for the block 1, first, in the direction in which the photodiodes PD of the line sensor LS are arranged, the pixel [2n-2] and the pixel [2n + 2] on both the left and right sides of the pixel [2n] to be corrected Based on the image information, the image information of the correction target pixel [2n] is corrected. This is because, as described above, in the case of block output, two adjacent pixels on both sides of the pixel to be corrected become two adjacent pixels in the physical arrangement of the line sensor LS.

  As for the block 2, in the direction in which the photodiodes PD of the line sensor LS are arranged, image information of the pixels [2n−1] and the pixels [2n + 3] adjacent to the left and right of the pixel [2n + 1] to be corrected Based on the above, the pixel [2n + 1] to be corrected is corrected. This is because, as described above, in the case of block output, two adjacent pixels on both sides of the pixel to be corrected become two adjacent pixels in the physical arrangement of the line sensor LS.

  It is the same as step S16 described above that various correction methods can be considered.

  After the process of step S26, or when it is determined that the pixel to be determined is not a pixel defect in step S24 described above (step S24: NO), the digital multi-function peripheral 10 acquires an image acquired from the line sensor LS. It is determined whether or not this processing has been performed for all of the data (step S28). That is, it is determined whether pixel defect determination and correction processing has been performed from pixel C [0] to pixel C [2 (N−1) +1].

  If it is determined that this process has not been performed for all pixels (step S28: NO), the digital multifunction peripheral 10 moves the determination target pixel to the next pixel and repeats the above-described step S22. Specifically, by adding 1 to n, two pixels to be judged are shifted to the right, and the above-described step S22 is repeated.

  On the other hand, when it is determined that this process has been performed for all the pixels (step S28: YES), the digital multi-function peripheral 10 ends the pixel defect correction process.

  As described above, according to the digital multi-function peripheral 10 according to the present embodiment, when the output mode from the line sensor LS is the normal output, the pixel defect using the two pixels adjacent to the left and right of the target pixel. When the output mode from the line sensor LS is the block output, the pixel defect is determined and corrected using the two pixels adjacent to the right and left sides of the target pixel. For this reason, even in the case of block output, pixel defects can be determined and corrected using two pixels adjacent to the left and right in the direction in which the photodiodes PD of the line sensor LS are physically arranged. For this reason, it is possible to determine and correct a pixel defect with reference to an appropriate pixel that can be expected to be most effective.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, the example in which the pixel defect correction process is executed by the CPU 20 has been described. However, the pixel defect correction process is executed by, for example, the control unit 50 provided in the scanner unit 28. May be. In this case, when the control unit 50 includes a CPU, the pixel defect correction processing can be realized by software as described above. However, when the control unit 50 is configured by hardware such as an ASIC, What is necessary is just to implement | achieve pixel defect correction processing in terms of wear.

  In the above-described embodiment, the present invention has been described by taking the case where the pixel sensor disposed in the line sensor LS is the photodiode PD as an example. However, the pixel sensor is not limited to the photodiode PD, and various types of pixels can be used. Can be used.

  In the above-described embodiment, the case where the document read by the ADF 56 is paper has been described as an example. However, this document is not limited to paper, and may be formed of another medium such as an OHP sheet.

  In the above-described embodiment, the case where the present invention is applied to the scanner unit 28 of the digital multifunction peripheral 10 has been described as an example. However, the application target of the present invention is not limited to the scanner unit 28 of the digital multifunction peripheral 10. It can be applied to all kinds of image reading apparatuses.

  Furthermore, for the automatic document reading process described in each of the above-described embodiments, a program for executing this pixel defect correction process is a flexible disk, a CD-ROM (Compact Disc-Read Only Memory), a ROM, a memory card, etc. It is possible to record on a recording medium and distribute in the form of a recording medium. In this case, the above-described embodiment can be realized by causing a program recorded on the recording medium to be read and executed by an image reading apparatus such as the digital multifunction peripheral 10.

  In addition, the image reading apparatus such as the digital multi-function peripheral 10 may include other programs such as an operating system and another application program. In this case, in order to utilize another program provided in the digital multifunction peripheral 10, a program that realizes processing equivalent to that of the above-described embodiment is called out from programs provided in the image reading apparatus such as the digital multifunction peripheral 10. A program including various instructions may be recorded on a recording medium.

  Furthermore, such a program can be distributed not as a recording medium but as a carrier wave through a network. The program transmitted in the form of a carrier wave on the network is taken into an image reading apparatus such as the digital multi-function peripheral 10, and the above-described embodiment can be realized by executing this program.

  Also, when a program is recorded on a recording medium or transmitted as a carrier wave on a network, the program may be encrypted or compressed. In this case, an image reading apparatus such as the digital multi-function peripheral 10 that has read the program from the recording medium or the carrier wave needs to execute the program after decoding or decompressing the program.

  In the above-described embodiment, the case where the pixel defect correction process is realized by software has been mainly described as an example. However, each of these processes may be realized by hardware such as an ASIC (Application Specific IC). . Furthermore, each of these processes may be realized by cooperation of software and hardware.

It is a block diagram explaining the structure of the line sensor used with the image reading apparatus which concerns on one Embodiment of this invention. FIG. 2 is a block diagram illustrating a correspondence relationship between image information generated by a photodiode and image information stored in an output register when the image information of the line sensor in FIG. 1 is output as a normal output. FIG. 2 is a block diagram illustrating a correspondence relationship between image information generated by a photodiode and image information stored in an output register when the image information of the line sensor in FIG. 1 is output as a block output. The figure which points out the physical image information of 2 adjacent pixels used when performing the process of determination and correction of the pixel defect of the nth pixel in normal output. The figure which shows the physical 4 pixel adjacent image information used when the pixel output of the 2nth and 2n + 1st pixel is determined and corrected in the block output. 1 is a block diagram illustrating an example of an internal configuration of a digital multifunction peripheral according to an embodiment of the present invention. FIG. 7 is a block diagram for explaining an example of an internal configuration of a scanner unit in the digital multifunction peripheral of FIG. 6. FIG. 7 is a flowchart illustrating an example of pixel defect correction processing executed by the digital multifunction peripheral of FIG. 6. The figure which points out the physical 2 pixel adjacent image information used when determining and correcting the pixel defect of the 2n-th and 2n + 1-th pixels in the block output.

Explanation of symbols

10 Digital MFP 20 CPU
22 RAM
24 ROM
26 Printer unit 28 Scanner unit 30 Hard disk drive 40 Internal bus

Claims (5)

A line sensor having a plurality of pixel sensors arranged in a line, wherein two pixel sensors are assigned to one output register;
As an output mode for outputting image information from the pixel sensor of the line sensor, after outputting image information of one pixel sensor assigned to one output register as first block image information, Block output executing means for outputting image information as second block image information, executing block output;
In the first block image information output by the block output execution unit, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined by the first block of the pixel sensor that is the determination target. First determination means for determining based on two pieces of image information on both sides in the image information;
The image information of the pixel sensor in the first block image information determined to be a defective pixel by the first determination means is adjacent to the first block image information of the pixel sensor determined to be the defective pixel. First correcting means for correcting based on two pieces of image information;
In the second block image information output by the block output execution means, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined by the second block of the pixel sensor that is the determination target. Second determination means for determining based on two pieces of image information on both sides in the image information;
The image information of the pixel sensor in the second block image information determined to be a defective pixel by the second determination means is adjacent to the second block image information of the pixel sensor determined to be the defective pixel. Second correction means for correcting based on two pieces of image information;
An image reading apparatus comprising: As an output mode for outputting image information from the pixel sensor of the line sensor, the image information of two pixel sensors assigned to one output register is added together as normal output image information which is one image information. Normal output executing means for executing normal output from the output register;
In the normal output image information output by the normal output execution means, whether or not the image information of the pixel sensor that is the determination target is a defective pixel, the normal output image information of the pixel sensor that is the determination target Third determination means for determining based on two pieces of image information adjacent to the left and right in
The image information of the pixel sensor in the normal output image information determined to be a defective pixel by the third determination means is adjacent to the left and right in the normal output image information of the pixel sensor determined to be the defective pixel. Third correcting means for correcting based on the two pieces of image information;
The image reading apparatus according to claim 1, further comprising:   The image reading apparatus according to claim 2, further comprising a switching unit that switches and executes the block output execution unit and the normal output execution unit.   A digital multifunction device comprising the image reading device according to claim 1. A control method of an image reading apparatus having a line sensor, wherein the pixel sensor has a plurality of pixel sensors arranged in a line and two pixel sensors are assigned to one output register,
As an output mode for outputting image information from the pixel sensor of the line sensor, after outputting image information of one pixel sensor assigned to one output register as first block image information, Outputting image information as second block image information, performing block output;
In the output first block image information, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is indicated on both sides of the first block image information of the pixel sensor that is the determination target. Determining based on two pieces of image information;
The image information of the pixel sensor in the first block image information determined to be the defective pixel is based on the two pieces of image information adjacent to each other in the first block image information of the pixel sensor determined to be the defective pixel. And correcting the process,
In the output second block image information, whether or not the image information of the pixel sensor that is the determination target is a defective pixel is determined on both sides of the second block image information of the pixel sensor that is the determination target. Determining based on two pieces of image information;
The image information of the pixel sensor in the second block image information determined to be the defective pixel is based on the two pieces of image information on both sides in the second block image information of the pixel sensor determined to be the defective pixel. And correcting the process,
An image reading apparatus control method comprising:

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