JP5807545B2 - Image reading device - Google Patents

Description

  The present invention relates to a technique for extracting an image of a document that has been entirely read from a plurality of documents that have been double-fed.

  Conventionally, when a plurality of originals are fed multiple times in an image reading apparatus such as a scanner or a copier, until the time required to read one original elapses after the start of reading the first original The image data read in the above is stored as image data representing the entire original document (see, for example, Patent Document 1).

JP 2007-104578 A

  By the way, the above-described conventional technique is based on the premise that the earliest document is a document that should be read first among a plurality of documents that are being fed. For example, if the third, fourth, and fifth sheets of all the originals are double-fed, the conventional technique assumes that the first original is the third original.

  However, when a plurality of documents are double-fed, the earliest document may not necessarily be the document that should originally be read first. For example, in the case of the above-described example, the fifth, fourth, and third originals may be fed in order. In this case, since the earliest document is the fifth document, the image represented by the image data stored as image data representing the entire third document is actually that of the fifth document. There is a problem that an image representing a part or an image representing a part of the fourth original is included.

  The present specification discloses a technique that can more reliably extract an image of a document that has been read entirely from a plurality of documents that have been multi-fed.

  An image reading apparatus disclosed in this specification includes a stacking unit on which one or more originals are stacked, a transporting unit that transports the originals stacked on the stacking unit one by one, and transported by the transporting unit. A reading unit that reads the document and generates an image; an output unit that outputs the image; and a processing unit, wherein the processing unit detects a double feed of the document; When a double feed is detected by the double feed detection process, a side of the original is detected from one image generated by reading the original group consisting of a plurality of the originals being fed by the reading unit. An edge detection process for detecting an edge representing a side extending in a direction orthogonal to the document transport direction, an image extraction process for extracting an area in which the interval between the adjacent edges in the one image is maximum, Output part And your, executes an output process of outputting the area extracted by the image extraction processing.

  Further, in the image extraction process, the processing unit may include an edge on the most upstream side among the one or more edges on the downstream side in the direction corresponding to the conveyance direction of the document in the one image, and the conveyance direction. A region sandwiched between the one or more edges on the upstream side in the direction corresponding to the edge on the most downstream side may be extracted.

  In addition, the image reading apparatus includes a notifying unit for notifying a user of information, and the processing unit controls the notifying unit to control a document other than a document to be originally read among the documents included in the document group. An informing process for informing the user of what number of all the originals is the original may be executed.

  In the notification process, the processing unit is originally read first from the number of documents and the number of edges read by the reading unit before the double feed is detected by the double feed detection process. It may be determined what number of originals other than the original should be.

  Further, in the notification process, the processing unit includes the number of edges on the downstream side in the direction corresponding to the transport direction across the region where the interval between the edges adjacent to each other in the one image is the maximum, and the If the number of edges on the upstream side is both 2 or more, the user may not be notified of what number of originals other than the original that should be read first.

  The image reading apparatus includes a detection unit that detects information correlated with the thickness of the document being conveyed by the conveyance unit, and the processing unit is configured to detect the document from the detection unit in the multifeed detection process. If the information indicating the thickness of two sheets or more is output, it may be determined that the document is being fed in multiple.

  When the double feed is detected by the double feed detection process, the processing unit executes a selection process for interrupting reading of the document and accepting a selection from the user to continue reading or to stop reading. When the selection process is selected to continue reading, the reading unit is controlled to continue reading the document, and when the selection process is selected to stop reading, the reading unit is selected. May be controlled to stop reading the original.

  This technique can be realized in various modes such as an image reading program, an image reading method, and a recording medium on which the image reading program is recorded.

  According to the above-described image reading apparatus, it is possible to more reliably extract an image of a document that has been read entirely from among a plurality of documents that have been multi-fed.

FIG. 3 is a schematic diagram of a stacking unit, a transport unit, and a reading unit according to the first embodiment. FIG. 3 is a block diagram showing an electrical configuration of the image scanner. FIG. 3 is a schematic diagram illustrating an example in which a document is double-fed. FIG. 3 is a schematic diagram illustrating an example in which a document is double-fed. FIG. 3 is a schematic diagram illustrating an example in which a document is double-fed. 6 is a flowchart showing a flow of document reading processing. 6 is a flowchart showing a flow of document reading processing. 6 is a flowchart showing a flow of document reading processing. The flowchart which shows the flow of an extraction process. The flowchart which shows the flow of a process in case the upstream edge is 2 or more and the downstream edge is one. The flowchart which shows the flow of a process when there is one upstream edge and two or more downstream edges. The flowchart which shows the flow of a reread alerting | reporting process. 9 is a flowchart showing a flow of document reading processing according to the second embodiment.

<Embodiment 1>
The first embodiment will be described with reference to FIGS.
(1) Configuration of Stacking Unit, Conveying Unit, and Reading Unit FIG. 1 illustrates a document tray 14 and an ADF (Auto Document Feeder) 15 included in an image scanner 1 (see FIG. 2) as an image reading apparatus according to the first embodiment. 2 is a schematic diagram showing a simplified configuration of a reading unit 30. FIG. The reading unit 30 also includes a device control unit 32, an AFE 33, and an image processing unit 34 shown in FIG. The document tray 14 is an example of a stacking unit. The ADF 15 is an example of a transport unit.

A housing 10 of the image scanner 1 is formed in a generally box shape, and a first platen glass 11 and a second platen glass 12 are juxtaposed on the top.
The document cover 13 is connected to the housing 10 so as to be rotatable between a closed posture that covers the platen glasses and an open posture that opens the platen glasses. The document cover 13 has a document tray 14 on which one or more documents are stacked, an ADF 15 that transports documents stacked on the document tray 14 one by one, and a sheet discharge tray on which documents transported by the ADF 15 are discharged. 16 etc. are provided.

  Inside the ADF 15, there are a separation roller 17, a suction roller 18, a conveyance roller 19, 20, and a discharge roller that are rotatably provided at the distal end of an arm that is pivotally supported by the shaft that supports the separation roller 17. A paper roller 21 and a plurality of driven rollers 22 that press against these are provided. The original is transported on the transport path T by these rollers, passes through a position where it is read by the reading device 23, and is discharged onto the paper discharge tray 16.

  The reading device 23 includes a light source composed of RGB RGB LEDs and the like, an image sensor in which a plurality of light receiving elements are linearly arranged in the direction perpendicular to the paper surface (main scanning direction), and reflected light reflected from the document. An optical system for forming an image on each light receiving element, a carriage on which these are mounted, and the like are provided.

  The transport mechanism 24 includes a driving roller 25, a driven roller (not shown), a timing belt 26 wound around these, a stepping motor (not shown), and the like.

  When reading a document placed on the first platen glass 11, the reading device 23 is transported by the transport mechanism 24 in the sub-scanning direction (A direction in the figure) parallel to the surface of the first platen glass 11, The original is read line by line while sequentially switching the color of the light source while being conveyed in the scanning direction, and an image signal is output to the AFE 33 described later.

  On the other hand, when reading a document transported by the ADF 15, the reading device 23 is moved directly below the second platen glass 12 by the transport mechanism 24, and sequentially switches the color of the light source in a state of being stopped just below the second platen glass 12. The original is read line by line, and an image signal is output to the AFE 33 described later.

  The ultrasonic sensor 26 is provided on one side facing the conveyance path T, and an ultrasonic generator 26a that generates an ultrasonic wave toward the other side. The ultrasonic sensor 26 is provided on the other side and receives the received ultrasonic wave. The ultrasonic receiving unit 26b outputs an output signal corresponding to the intensity of the sound wave to the control unit 31. The ultrasonic sensor 26 is an example of a detection unit.

The document detection sensor 27 is a sensor that detects a document stacked on the document tray 14 and outputs a detection signal to the control unit 31.
The trailing edge detection sensor 28 is a sensor that detects the trailing edge of the document at a detection position upstream of the position read by the reading device 23 and outputs a trailing edge detection signal to the control unit 31.

(2) Electrical Configuration of Image Scanner FIG. 2 is a block diagram showing the electrical configuration of the image scanner 1. The image scanner 1 includes a control unit 31, an ADF 15, a device control unit 32, an AFE (Analog Front End) 33, a reading device 23, a transport mechanism 24, an image processing unit 34, a display unit 35, an operation unit 36, a communication interface unit 37, An ultrasonic sensor 26, a document detection sensor 27, a rear end detection sensor 28, and the like are provided.

  The control unit 31 includes a CPU 38, a ROM 39, a RAM 40, and the like. The CPU 38 controls each unit of the image scanner 1 by executing various programs stored in the ROM 39. The ROM 39 stores a control program executed by the CPU 38 and various data. The RAM 40 is used as a main storage device for the CPU 38 to execute various processes. In addition, the RAM 40 stores various counters and flags used in processing to be described later. The control unit 31 is an example of a processing unit.

The device control unit 32 is a circuit that controls the light source and the image sensor of the reading device 23 under an instruction from the control unit 31.
The AFE 33 is a circuit that performs gain adjustment of the image signal output from the image sensor, A / D conversion for converting the gain-adjusted image signal into a digital image signal, and the like. In the following description, the A / D converted image signal is referred to as read data.
The image processing unit 34 reads the read data output from the AFE 33 and stored in the RAM 40, and performs gamma correction, shading correction, and other various image processing to generate an image having three RGB density values for each pixel. Circuit.

The display unit 35 includes a display device such as a liquid crystal display, a drive circuit that drives the display device, and the like. The display unit 35 is an example of a notification unit.
The operation unit 36 includes various buttons for the user to operate the image scanner 1 such as a button for instructing the user to read a document and a button for operating a GUI (Graphical User Interface) displayed on the display unit 35. Has a button.

  The communication interface unit 37 is an interface for communicating with an external device such as a personal computer via a communication network such as a LAN (Local Area Network), a USB (Universal Serial Bus), a parallel line, or the like. The communication interface unit 37 is an example of an output unit.

  The image scanner 1 according to the first embodiment is configured to be able to perform so-called PC scanning, and when an external device is instructed to read a document, the image scanner 1 reads the document to generate an image, and the generated image is output to the external device. Send to.

(3) Example in which documents conveyed by ADF are double-fed FIG. 3 to FIG. 5 are schematic diagrams showing examples in which documents conveyed by ADF 15 are double-fed. 3 to 5 show a case where the document M conveyed on the second platen glass by the ADF 15 is viewed from the reading device 23.

  FIG. 3 shows a case where the third, fourth, and fifth originals M are double-fed. In this case, from among the three originals M to be originally read out of these three originals M, FIG. The case where the front end portion on the downstream side in the conveyance direction of the fifth original M and the front end portion on the downstream side in the conveyance direction of the fourth original M are read first. The third, fourth, and fifth originals M are an example of a group of originals composed of a plurality of multi-fed originals. It should be noted that the original document that should be read first may be the original document that was to be conveyed in the earliest order when it was stacked on the original document tray 14 among the multiple fed documents M.

  In FIG. 3, an image 50 indicates one image generated by reading a document group including a plurality of documents M that are double-fed. Edges 51 to 54 that extend linearly in the horizontal direction in the image 50 indicate edges that are sides of the document M and extend in a direction orthogonal to the conveyance direction of the document M.

  By the way, when a plurality of originals are double-fed, the original that should be read first among the plurality of originals when the plurality of originals are read by the reading unit 30 (the highest in FIG. 3). Therefore, even if the original that should be read first is double-fed together with other originals, the entire original is read. On the other hand, a part of the other document that is being double-fed is hidden by the document below it, so that a part of the document cannot be read.

  That is, in one image generated by reading a document group composed of a plurality of documents that have been multi-fed, the region in which the interval between edges representing the sides extending in the direction orthogonal to the document transport direction is maximized This represents the entire original that should be read first among the plurality of originals. In the example shown in the drawing, since the original document to be read first among the third, fourth, and fifth originals M is the third original M, a plurality of areas 55 sandwiched between the edges thereof, An area 57 in which the interval between the edges is the maximum among the edges 56 and 57 represents the entire third original M.

  Therefore, the image scanner 1 extracts the region 57 in which the interval between the edges is maximum as an image of the entire document that should be read first. In this way, it is possible to eliminate the need for re-reading a document that should originally be read first among a plurality of documents that have been multi-fed.

  Here, the number of originals that should be read first among a plurality of originals M being fed is the number of originals that have been read before that. It can be specified as the number obtained by adding 1. For example, since the reading of the first and second originals M has been completed in the illustrated example, the original that should be read first is the third original M.

  The image scanner 1 determines the number of documents fed in double from the number of edges representing sides extending in a direction orthogonal to the document conveyance direction in the above-described one image. Then, the image scanner 1 determines the number of the originals other than the original that should be read first among the multiple fed originals, and rereads the originals. Inform the user as a required document. In the case of the example shown in the figure, the fourth and fifth originals M are notified as originals that need to be read again.

  FIG. 4 shows a case where the third, fourth, and fifth originals M are double-fed. Of these three originals M, the entire third original M to be read first is read first. Then, the rear end portion of the fourth original M and the rear end portion of the fifth original M are read. An image 60 shows one image generated by reading a group of documents composed of a plurality of documents fed in a double feed.

  Also in the example shown in FIG. 4, the region 65 where the distance between the edges is the maximum is the third original, which is the original that should be read first, among the third, fourth, and fifth originals M. M represents the whole. Then, the fourth and fifth originals are notified as originals that need to be read again.

FIG. 5 shows a case where more originals are double fed. In FIG. 5, an image 70 shows one image generated by reading a document group composed of a plurality of documents fed in a double feed.
In the example shown in FIG. 3 and FIG. 4 described above, there are a plurality of edges only on either the upstream side or the downstream side in the direction corresponding to the transport direction across the region where the interval between adjacent edges is the largest. Although the case where there is only one edge on the other side is shown, there are a plurality of edges on both the upstream side and the downstream side in FIG. Also in this case, the region 71 in which the interval between the edges is the maximum is extracted as an image of the entire document that should be read first.

However, if there are a plurality of edges on both the upstream side and the downstream side, there is a risk of misjudging if the number of documents fed in duplicate is determined from the number of edges. This is because the sixth and seventh originals are hidden, and the original M seen on the upstream side in the conveyance direction of the third original is the eighth original M and the ninth original M. This is because there is a possibility.
Therefore, when there are a plurality of edges on both the upstream side and the downstream side in the direction corresponding to the conveyance direction, the image scanner 1 notifies the user that the document needs to be read again, but needs to be read again. It does not notify the original number of all originals.

(4) Document Reading Processing FIGS. 6 to 8 are flowcharts showing the flow of document reading processing by the image scanner 1. This process is started when a PC scan is instructed from an external device.

In step S101, the control unit 31 initializes a reading number counter that counts the number of originals to be read to zero.
In S102, the control unit 31 adds 1 to the reading sheet counter.
In S103, the control unit 31 initializes various counters used in this processing to 0, and sets various flags to OFF as an initial value.

In step S <b> 104, the control unit 31 controls the reading unit 30 to read the original for one line, and acquires read data for one line from the reading unit 30. The control unit 31 stores the acquired read data in the RAM 40.
In S105, the control unit 31 detects double feeding. Specifically, for example, when the control unit 31 acquires an output signal from the ultrasonic sensor 26 and acquires an output signal indicating the thickness of two or more originals, the control unit 31 determines that the originals are being double-fed. When the control unit 31 determines that the document is being double-fed, the control unit 31 turns on the double-fed flag. The output signal of the ultrasonic sensor 26 is an example of information indicating the thickness of two or more originals. S105 is an example of a double feed detection process.

In S106, the control unit 31 determines whether or not the double feed flag is on. If it is on, that is, if the document is double-fed, the process proceeds to S107. If it is off, that is, the document is double-fed. If not, the process proceeds to S116.
In S107, the control unit 31 controls the reading unit 30 to interrupt reading.

In S <b> 108, the control unit 31 displays a message indicating that the document is being double-fed on the display unit 35, and waits until the user presses a predetermined button on the operation unit 36. When the user presses a predetermined button, the control unit 31 proceeds to S109.
In S109, the control unit 31 causes the display unit 35 to display a message asking the user whether to continue or stop reading the document, and the user operates the operation unit 36 to select either continuation or cancellation. Wait until. The control unit 31 proceeds to S110 when the user selects continuation, and proceeds to S118 when the user selects cancellation. S109 is an example of a selection process.

In S <b> 110, the control unit 31 controls the reading unit 30 to read the original for one line, and obtains read data for one line from the reading unit 30. The control unit 31 stores the acquired read data in the RAM 40.
In S111, the control unit 31 determines whether or not the reading of the document is completed. Specifically, when the trailing edge detection signal is output from the trailing edge detection sensor 28, the control unit 31 continues reading until a predetermined time elapses, and determines that the reading of the document is finished when the certain time elapses. This fixed time corresponds to the time required for the trailing edge of the document to reach the position where it is read by the reading device 23.
If the reading of the document is completed (S111: Yes), the control unit 31 proceeds to S112, and if not completed (S111: No), the control unit 31 returns to S110 and repeats the process.

  During the reading of the original, the image processing unit 34 generates an image for the predetermined number of lines from the read data every time the read data for the predetermined number of lines is stored in the RAM 40, and the generated image is stored in the RAM 40. Remember. By repeating this, one image that finally represents the original (a group of originals when a plurality of originals are double-fed) is generated.

  In S112, the control unit 31 executes an extraction process. The extraction process is a process of extracting an image of the entire original that should originally be read first from among the plurality of originals from one image generated by reading a group of originals made up of a plurality of multi-fed originals.

In step S113, the control unit 31 transmits the image extracted in step S112 to an external apparatus as an original image that should be read first. Here, the number of original documents to be read first is specified by the value of the read number counter. S113 is an example of output processing.
In S114, the control unit 31 obtains a detection signal from the document detection sensor 27 and determines whether or not there is a next document on the document tray 14, and if there is no next document (S114: No), the process proceeds to S115. If there is a next original (S114: Yes), the process returns to S102.

  In S115, the control unit 31 executes a reread notification process. The re-reading notification process is a process for notifying the user that re-reading is necessary when double feeding of documents is detected.

S116 to S117 are processes when it is determined in S106 that the double feed flag is off.
In S116, the control unit 31 determines whether or not the reading of the document has been completed. If the reading has been completed (S116: Yes), the process proceeds to S117. repeat.
In S117, the control unit 31 transmits an image of one original document generated by the image processing unit 34 and stored in the RAM 40 to an external device.

S118 to S119 are processes performed when the user selects to cancel reading in S109.
In S118, the control unit 31 discards all the read data stored in the RAM 40 in S104.
In step S119, the control unit 31 controls the reading unit 30 to discharge a document being read.

(5) Extraction Processing FIG. 9 is a flowchart showing the flow of extraction processing executed in S112.
In step S <b> 201, the control unit 31 reads an edge representing a side of the document that extends in a direction orthogonal to the document transport direction from one image generated by reading a document group including a plurality of documents fed in a double feed. To detect. S201 is an example of edge detection processing.

In S <b> 202, the control unit 31 specifies an area in which the interval between adjacent edges is the maximum in one image generated by reading a document group composed of a plurality of documents that have been multi-fed.
Specifically, for example, when the direction corresponding to the conveyance direction in the one image is the Y direction, the control unit 31 specifies the Y coordinate of each edge, and the difference in the Y coordinate between adjacent edges is the largest. A large area is specified as an area where the interval between adjacent edges is maximum.

  In S203, the control unit 31 has two or more edges on the upstream side and the downstream side in the direction corresponding to the document transport direction across the area specified in S202 in the one image, or the upstream side and the downstream side. If there is only one edge, the process proceeds to S204. If the number of upstream edges is 2 or more and the number of downstream edges is one, the process proceeds to S205, where there is one upstream edge and the downstream edge. If is 2 or more, the process proceeds to S206.

In S <b> 204, the control unit 31 extracts a region having the maximum interval from regions sandwiched between adjacent edges in the one image.
In step S205, the control unit 31 executes processing when there are two or more upstream edges and one downstream edge.
In S206, the control unit 31 executes processing when there is one upstream edge and two or more downstream edges.
S204 to S206 described above are an example of image extraction processing.
In S207, the control unit 31 turns on the reread notification flag.

(6) Processing when there are two or more upstream edges and one downstream edge FIG. 10 is a flowchart showing a processing flow when there are two or more upstream edges and one downstream edge. .
In step S <b> 301, the control unit 31 determines the number of documents fed in double from the number of edges on the upstream side.

In S <b> 302, the control unit 31 determines a document that needs to be read again from the number of documents fed in double and the value of the number-of-reads counter.
For example, if the number of documents fed double is 3 and the value of the reading sheet counter is 3, the documents fed double are 3, 4 and 5. Of these, the image of the third original, which is the original that should be read first, is extracted from the above-mentioned one image, so that re-reading is unnecessary. Accordingly, in this case, the originals that need to be read again are the fourth and fifth originals.

In step S303, the control unit 31 stores information indicating the document that needs to be re-read determined in step S302 in the RAM 40 as re-read document information. For example, in the example shown in S302, information indicating the fourth and fifth sheets is stored as the reread document information.
In S304, the control unit 31 turns on the reread document notification flag.
In S <b> 305, the control unit 31 extracts an area in which the interval between adjacent edges in the one image described above is the maximum as an image of a document that should be originally read from among the plurality of documents that have been fed. For example, in the example shown in S302, an area where the interval between adjacent edges is the maximum is extracted as an image of the third original.

(7) Processing when there is one upstream edge and two or more downstream edges FIG. 11 is a flowchart showing a processing flow when there is one upstream edge and two or more downstream edges. It is. Here, processes that are substantially the same as those in the flowchart shown in FIG.
In step S <b> 401, the control unit 31 determines the number of documents fed in double from the number of edges on the downstream side.

(8) Reread Notification Process FIG. 12 is a flowchart showing the reread notification process executed in S115.
In S501, the control unit 31 determines whether or not the reread notification flag is on. If it is on, the control unit 31 proceeds to S502, and if it is off, the process ends and returns.

In S502, the control unit 31 determines whether or not the reread document notification flag is on. If it is off, the control unit 31 proceeds to S503, and if it is on, proceeds to S504.
In S503, the control unit 31 notifies the user that rereading is necessary. For example, the control unit 31 causes the display unit 35 to display a message stating that “there is a multi-fed document. The document needs to be read again”.

  In step S <b> 504, the control unit 31 notifies the user that re-reading is necessary and how many originals have been double-fed. For example, when 4 and 5 are stored as the reread document information described above, the control unit 31 displays a message on the display unit 35 that “the fourth and fifth documents need to be read again”. Display. S504 is an example of a notification process.

(9) Effects of the Embodiment The image scanner 1 according to the first embodiment described above represents a side extending in a direction orthogonal to the document conveyance direction from one image generated by reading the multi-feed document group. Edges are detected, and a region where the interval between adjacent edges is maximized is extracted.
In this way, even if the earliest original document among the plurality of originals that are being fed is not the original document that should be read first, the original image that should be read first can be extracted. For example, as shown in FIG. 3, even if the fifth, fourth, and third documents are fed in order, an image representing the entire third document is obtained from one image generated by reading these documents. Can be extracted.
Therefore, according to the image scanner 1, it is possible to more reliably extract an image of a document that has been read entirely from among a plurality of documents that have been multi-fed.

Further, according to the image scanner 1, compared to the conventional technique using an ultrasonic sensor, an image of a document in which the entire document is read can be extracted more reliably.
More specifically, in the prior art, using the ultrasonic wave transmitted and received by the ultrasonic sensor, it is determined whether or not the double feed is made based on the result of the attenuation of the ultrasonic wave. The leading and trailing edges of the earliest document were detected from the result of ultrasonic attenuation. However, in this method, the difference between the attenuation results of the received ultrasonic waves becomes smaller as the number of documents fed in multiple increases, so that it becomes difficult to detect the leading edge and the trailing edge of the document when the number of documents is large. . For this reason, there is a problem in that it becomes difficult to acquire image data corresponding to the area of the original as the number of originals to be double fed increases.
On the other hand, according to the image scanner 1, since the area having the maximum area is extracted from the areas sandwiched between the adjacent edges, the image scanner 1 is generated by reading a plurality of multi-fed originals as compared with the conventional technique. An image of a document in which the entire document is read from the plurality of documents can be more reliably extracted from one image.

  Furthermore, according to the image scanner 1, the user can determine how many originals of the originals other than the original that should be read first among the originals included in the original group consisting of the multiple fed originals. To inform. When a document is double-fed, if the user is notified of how many originals have been double-fed, the user can know what number of originals should be read again, which improves user convenience. .

  Furthermore, according to the image scanner 1, the original is first read out of the originals included in the multifeed original group from the number of originals and the number of edges read by the reading unit 30 before the double feed is detected. By determining the number of originals other than the original should be determined, it is possible to determine how many originals have been double-fed.

Furthermore, according to the image scanner 1, both the number of edges on the upstream side and the number of edges on the downstream side in the direction corresponding to the conveyance direction across the region where the distance between adjacent edges in the image is maximized are both included. When the number is two or more, the user is not notified of the number of originals other than the original that should be read first among the originals included in the double-fed original group.
If the number of edges on the upstream side and the number of edges on the downstream side in the direction corresponding to the conveyance direction across the area where the interval is maximum is two or more, the number of documents fed in double is the edge There is a risk of misjudging if judging from numbers.
According to the image scanner 1, when the number of edges on the upstream side and the number of edges on the downstream side are both 2 or more, the user is not notified of which document is, so what document is It is possible to suppress erroneous notification of whether double feeding has been performed.

Further, according to the image scanner 1, when the output signal indicating the thickness of two or more originals is output from the ultrasonic sensor 26, it is determined that the originals are double-fed so that the originals are double-fed. It can be determined whether or not.
Further, according to the image scanner 1, the user can select whether to continue reading or to stop reading the original when it is determined that the original is being fed double.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to FIG.
In the first embodiment, an example is described in which a double feed is detected in the middle of reading one original, and a message indicating that the original is being double fed is displayed during the reading of the original when the original is double fed. However, in the second embodiment, the double feed is detected after the reading of the document is completed.
In the second embodiment, a facsimile (FAX) apparatus will be described as an example of the image reading apparatus.

  FIG. 13 is a flowchart showing the flow of document reading processing according to the second embodiment.

In step S <b> 601, the control unit 31 initializes a read number counter that counts the number of originals read to 0.
In step S602, the control unit 31 adds 1 to the reading sheet counter.
In S603, the control unit 31 initializes various counters used in this processing to 0, and sets various flags to OFF as initial values.

In step S <b> 604, the control unit 31 controls the reading unit 30 to read the original for one line, and acquires read data for one line from the reading unit 30. The control unit 31 stores the acquired read data in the RAM 40.
In S605, the control unit 31 determines whether or not the reading of the document has been completed. If it has been completed (S605: Yes), the process proceeds to S606. repeat.

In S606, the control unit 31 detects double feeding. The control unit 31 turns on the double feed flag when it is detected that the original is being double fed by detecting the double feed.
Specifically, the double feed detection may be performed using, for example, an output signal output from the ultrasonic sensor 26 during reading of an original and storing the output signal. Alternatively, the user can specify the document size before starting to read the document, and the number of pixels of the generated image corresponding to the direction in which the document is conveyed and the document size specified by the user May be performed by comparing the number of pixels corresponding to. In this case, when the number of pixels of the generated image is larger than the number of pixels corresponding to the designated document size, double feeding of the document is detected.

In S607, the control unit 31 proceeds to S608 when the double feed flag is on, and proceeds to S613 when it is off.
In S608, the control unit 31 executes an extraction process.
In step S <b> 609, the control unit 31 transmits the extracted image as a document image for one fax.

In S610, the control unit 31 executes a reread notification process.
In step S <b> 611, the control unit 31 displays a message for inquiring the user whether or not preparation for rereading is completed on the display unit 35, and waits until the user presses a predetermined button on the operation unit 36. The user returns to the document tray 14 to reread the double-fed document, and then presses the predetermined button described above.

In S612, the control unit 31 determines whether or not there is a next document on the document tray 14, and if there is a next document (S612: Yes), the process returns to S602, and if there is no next document (S612: No). Ends this processing.
In step S <b> 613, the control unit 31 transmits the image of one original stored in the RAM 40 by FAX.

  According to the image scanner 1 according to the second embodiment described above, it is possible to more reliably extract an image of a document that has been read entirely from among a plurality of documents that have been multi-fed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and the drawings, and for example, the following embodiments are also included in the technical scope.

  (1) In the above-described embodiment, the case where the region having the largest Y coordinate difference between the adjacent edges is extracted as the region having the maximum interval between the adjacent edges has been described as an example. Among the one or more edges on the upstream side in the direction corresponding to the transport direction, the edge on the most downstream side, and on the most upstream edge among one or more edges on the downstream side in the direction corresponding to the transport direction The sandwiched region may be extracted as a region where the interval between adjacent edges is maximized.

For example, in the case of the example shown in FIG. 3, the edge on the most downstream side among the one or more edges on the upstream side in the direction corresponding to the document transport direction in one image 50 is the edge 54, which corresponds to the transport direction. Of the one or more edges 51, 52, 53 on the downstream side in the direction, the edge on the most upstream side is the edge 53, and the region sandwiched between these edges is the region 57.
In this case, an intermediate position in the direction corresponding to the document conveyance direction in one image may be a position that divides the one image into the upstream side and the downstream side.

  (2) In the above embodiment, the control unit 31 is described as an example of the processing unit. However, the processing unit may be configured by the control unit 31 and the image processing unit 34.

DESCRIPTION OF SYMBOLS 1 ... Image scanner, 14 ... Document tray, 15 ... ADF, 23 ... Reading device, 24 ... Conveyance mechanism, 32 ... Device control part, 33 ... AFE, 34. ..Image processing unit, 35... Display unit, 36... Operation unit, 37 .. communication interface unit, 50... Image, 51 to 54. 60 ... image, 65 ... area, 70 ... image, 71 ... area

Claims (6)

A stacking unit on which one or more documents are stacked;
A transport unit that transports the originals stacked on the stack unit one by one;
A reading unit that reads the original document transported by the transport unit and generates an image;
An output unit for outputting the image;
A processing unit;
With
The processor is
A double feed detection process for detecting double feed of the document;
When a double feed is detected by the multi-feed detection process, a side of the original is obtained from one image generated by reading the original group consisting of a plurality of the originals being multi-feeded by the reading unit. Edge detection processing for detecting an edge representing a side extending in a direction perpendicular to the document conveyance direction;
An image extraction process for extracting an area in which the interval between the edges adjacent to each other in the one image is maximum;
An output process for controlling the output unit to output an area extracted by the image extraction process;
An image reading apparatus that executes The image reading apparatus according to claim 1 ,
A notification unit for notifying the user of information;
The processing unit controls the notifying unit to notify the user of what number of originals other than the original that should be read first among the originals included in the original group. An image reading apparatus that executes notification processing. The image reading apparatus according to claim 2 ,
In the notification process, the processing unit originally reads a document to be originally read from the number of documents and the number of edges read by the reading unit before the double feed is detected by the double feed detection process. An image reading apparatus that determines the number of originals other than the originals. The image reading apparatus according to claim 3 ,
In the notification process, the processing unit includes the number of edges on the downstream side in the direction corresponding to the transport direction across the region where the interval between the edges adjacent to each other in the one image is maximum, and the transport direction. When the number of edges on the upstream side in the direction corresponding to is both 2 or more, the user is not notified of which original document other than the original document that should be read first is the original document, Image reading device. An image reading apparatus according to any one of claims 1 to 4 ,
A detection unit that detects information correlated with the thickness of the document being conveyed by the conveyance unit;
In the multi-feed detection process, the processing unit determines that the original is being double-fed when the information indicating the thickness of two or more sheets of the original is output from the detection unit. apparatus. An image reading apparatus according to any one of claims 1 to 5 ,
The processor is
When a double feed is detected by the double feed detection process, the reading of the original is interrupted, and a selection process for receiving a selection from the user to continue reading or to stop reading is executed.
When the selection process is selected to continue reading, the reading unit is controlled to continue reading the document, and when the selection process is selected to stop reading, the reading unit is controlled. An image reading device that stops reading the original.

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