JP2010124092A - System and method of reading image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To read images without distortion over the entire recording medium. <P>SOLUTION: In an image reading system, a check processing system includes: a reading unit (read head 82 or 83) for reading the image of the recording medium; a first carrying unit (carrying roller 52 and pressing roller 62) provided more on the upstream than the reading unit; a second carrying unit (carrying roller 53 and pressing roller 63) provided more on the downstream than the reading unit; and a read image generation unit 104 for generating the read image of the recording medium on the basis of the image read by the reading unit when the second carrying unit sends out the recording medium to the downstream side of a read position when carrying the recording medium in a forward direction from the upstream side to the downstream side and reading the image and the image read by the reading unit when the first carrying unit sends out the recording medium from the read position to the upstream side when carrying the recording medium in an opposite direction from the downstream side to the upstream side and reading the image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading system and an image reading method for reading an image related to a medium such as a check while conveying the medium in a conveyance path.

  2. Description of the Related Art Readers that illuminate a sheet to be read and read reflected light with an imaging device such as a CCD and convert it into digital data are well known. For example, Patent Document 1 describes a reading apparatus configured to reciprocate sub-scanning and recognize an effective portion in which information is distributed over a predetermined range of a document during scanning in which a main scanning position is moved forward. Map the information on the manuscript during the forward movement when the original image information is not photoelectrically converted, and the map information shortens the manuscript scanning time, the transmission time, and the recording time during the backward movement. It is intended.

  Patent Document 2 describes a mark sheet reading apparatus that conveys a sheet and reads a sheet-like mark. It has a reading head in which mark reading elements are arranged every other row direction in the sheet information column, conveys the sheet in the forward direction, reads the mark, and then moves the reading head one row in the row direction. Are conveyed in the reverse direction to read the remaining marks. The number of mark reading elements and amplifiers are halved.

  By the way, a check processing apparatus for processing checks is known as a medium processing apparatus for processing sheet-like media. In the check processing apparatus, a reading head and a magnetic head are arranged along the conveyance path, and images and magnetic ink characters of the checks conveyed along the conveyance path are read, and the checks are classified according to the reading result. (See, for example, Patent Document 3).

  In an image scanner that reads an image, an original is transported in front of a reading head, but there is a case where a read image for a certain length is distorted after the leading edge of the original passes the reading position.

This will be specifically described. When there are conveying rollers on both sides so as to sandwich the reading head, when the document moves from the conveying roller in front of the reading head to the conveying roller in the back, the following two types of different forces are applied to the document.
(1) A document is nipped between a conveyance roller and a pressing roller in front of the reading head, and is conveyed forward when the conveyance roller rotates. A force that pushes the document in the direction of travel works. This situation continues until the leading edge of the document reaches the transport roller and presser roller at the back of the head.
(2) When the leading edge of the original reaches the position of the conveying roller and the pressing roller immediately behind the reading head and the conveying roller rotates, the original is further conveyed forward. At this time, a tensile force is applied to the document between the two transport rollers that sandwich the reading head. This situation continues until the end of the document passes the read head.

Japanese Patent Laid-Open No. 54-50218 JP 55-153072 A Japanese Patent Application Laid-Open No. 2008-211154 (page 4 to page 6, FIG. 1)

  FIG. 13 is a schematic diagram for explaining a state in which the document passes in front of the reading head of the reading head 83. In the state of conveyance from the state (a) to the state (c) in the figure, the force that the document receives in the vicinity of the reading head is the pushing force of the roller and the friction in the document path. It may bend (see (b) in the figure). When this deflection occurs, the document transport speed near the reading head is not constant, and the read image may be distorted. Even if the methods described in Patent Documents 1 and 2 described above are employed, image distortion cannot be eliminated.

  The present invention has been made in order to solve the above-described problem, and can obtain an image without distortion from an image read by a reading device having conveyance rollers on both sides so as to sandwich a reading head (reading unit). An object of the present invention is to provide an image reading system and an image reading method.

An image reading system of the present invention that can solve the above-described problems includes a reading unit that reads an image on a recording medium, a first transport unit provided upstream of the reading unit, and a downstream side of the reading unit. A second transport unit provided in
When reading the image by transporting the recording medium from the upstream side to the downstream side in the forward direction, the image read by the reading unit when the second transport unit sends the recording medium downstream from the reading position; When the recording medium is conveyed in the reverse direction from the downstream to the upstream to read the image, the first conveyance unit reads the recording medium from the reading position to the upstream side, and the image that is read by the reading unit. And a read image generation unit that generates a read image of the recording medium.

  According to the above configuration, the image is read by reciprocating the recording medium in the forward direction and the reverse direction. The read image read while receiving the tensile force by the second transport unit in the forward direction and the read image read while receiving the tensile force by the first transport unit in the reverse direction are appropriately combined and combined. Thus, it is possible to generate a read image having no distortion over the whole. As a result, the recognition rate in OCR (optical character recognition) or the like is improved, and highly accurate reading determination can be performed.

Further, in the image reading system of the present invention, when the image is read in the reverse direction, the reading unit stops the reading process when reading the image formed in the predetermined area of the recording medium,
The first conveyance unit and the second conveyance unit change conveyance of the recording medium in the reverse direction to a forward direction.

  According to the above configuration, when an image formed in a predetermined area is read during conveyance in the reverse direction, the reading process is stopped and the conveyance is changed to forward conveyance, so there is no need to read the entire recording medium. For example, if a check is to be read, if the entire image is read during forward conveyance and important information formed in a predetermined area is read during reverse conveyance, the reading accuracy of important information parts can be read. The processing time for reciprocal reading can be shortened while increasing.

In addition, the present invention that can solve the above-described problems is provided with a reading unit that reads an image of a recording medium, a first transport unit that is provided upstream of the reading unit, and a downstream of the reading unit. An image reading method in an image reading system comprising:
A first reading step for reading the image by conveying the recording medium in the forward direction from upstream to downstream; a second reading step for reading the image by conveying the recording medium in the reverse direction from downstream to upstream; An image read by the reading unit when the second conveying unit sends the recording medium downstream from a reading position in one reading step, and the first conveying unit in the second reading step And an image generation step of generating a read image of the recording medium based on an image read by the reading unit when the recording medium is sent upstream from the reading position.

  According to the above configuration, the image is read by reciprocating the recording medium in the forward direction and the reverse direction, and only the undistorted area where reading is performed while receiving the tensile force is used as the read image. Therefore, by appropriately combining and synthesizing each, a read image without distortion can be generated. Thereby, the recognition rate in OCR or the like is improved, and highly accurate reading determination can be performed.

In the image reading method of the present invention, in the second reading step,
When an image formed in a predetermined area of the recording medium is read, the reading process is stopped, and the reverse conveyance of the recording medium is changed to the forward direction.

  According to the above configuration, when an image formed in a predetermined area is read during conveyance in the reverse direction, the reading process is stopped and the conveyance is changed to forward conveyance, so there is no need to read the entire recording medium. For example, if a check is to be read, if the entire image is read during forward conveyance and important information formed in a predetermined area is read during reverse conveyance, the reading accuracy of important information parts can be read. The processing time for reciprocal reading can be shortened while increasing.

Embodiments of an image reading system of the present invention will be described below in detail with reference to the drawings. Hereinafter, a check reading system will be exemplified and described as an embodiment.
The check reading system according to the present embodiment includes a host computer and a check processing device that is communicably connected to the host computer.

First, the check processing device will be described.
(overall structure)
FIG. 1 is an external perspective view of a check processing apparatus according to the present embodiment. The check processing apparatus 1 includes a main body case 2 on the apparatus main body side and left and right opening / closing covers 3 and 4. A check conveyance path 6 for conveying the check 5 is formed between the main body case 2 and the opening / closing covers 3 and 4. The check conveyance path 6 is defined by a narrow vertical groove extending in a substantially U shape when viewed from above. The upstream end of the check conveyance path 6 in the check conveyance direction is connected to a check supply unit 8 composed of a wide vertical groove via a check delivery path 7 composed of a narrow vertical groove. The downstream end of the check conveyance path 6 passes through left and right branch passages 9 and 10 consisting of narrow vertical grooves branching left and right, and first and second check discharge sections 11 consisting of left and right wide vertical grooves. , 12.

  FIG. 2 is a schematic view of a check processed by the check reading apparatus according to the present embodiment. As shown in FIG. 2, the check 5 has a magnetic ink character string 5A printed in the long side direction at the lower end portion of the surface 5a. In addition, on the front surface 5a, an amount, a payer, a number, a signature, and the like are written on a background of a predetermined pattern, and a back-end column and the like are provided on the back surface 5b. The check 5 is inserted into the check supply unit 8 so that the vertical direction is aligned and the surface 5 a faces the outside of the U-shaped check conveyance path 6.

  The check 5 sent from the check supply unit 8 through the check delivery path 7 is conveyed along the check conveyance path 6 while being printed on the front surface 5a of the magnetic ink character string 5A, its front image and back image. Is read. The check 5 from which these pieces of information are normally read is distributed to the first check discharge unit 11 and printed there after printing such as “electronic payment completed”. The check 5 in which unreadable or abnormal reading occurs is distributed to the second check discharge unit 12 without being printed, and discharged there.

  FIG. 3 is an external perspective view showing the check processing device 1 in a state in which the opening / closing covers 3 and 4 are opened and the check transport path 6 is opened, and FIG. 4 is a plan view thereof. Referring to these figures as well, the main body case 2 includes a central case portion 22 having a contoured vertical outer peripheral side portion 21 along the U-shaped check conveyance path 6, and left and right side case portions. 23, and a partition case portion 25 disposed between the central case portion 22 and the side case portion 24. A check supply unit 8 is formed between the central case portion 22 and the side case portion 23. The central case portion 22 and the other side case portion 24 are divided into left and right by a partition case portion 25 to form check discharge portions 11 and 12.

  The outer peripheral side surface portion of the central case portion 22 protruding from the left and right side case portions 23 and 24 is a main body side guide surface 21 for guiding the check 5, and the main body side guide surface 21 is opened and closed from the left and right. Covered by covers 3 and 4. The opening / closing cover 3 is disposed on the side case portion 23 side, and the cover side guide surface 30 on the inner side faces the main body side guide surface 21 at a constant interval. The upstream conveyance path portion 6 a is defined by a vertical groove opened upward defined by the side guide surface 30.

  Similarly, the opening / closing cover 4 is disposed on the side case portion 24 side, and the cover side guide surface 40 inside thereof is opposed to the main body side guide surface 21 at a constant interval. The downstream conveyance path portion 6b is defined by a vertical groove that opens upward defined by the cover-side guide surface 40.

  It should be noted that the front end 3a of the open / close cover 3 and the front end 4a of the open / close cover 4 can be opened and closed left and right about a vertical open / close central shaft 26 disposed on the body case 2 side. 26 is attached.

  Next, the open / close covers 3 and 4 are locked at their closed positions by a lock mechanism. As shown in FIGS. 3 and 4, the lock mechanism of the open / close cover 3 is attached to the cover side engaging claw 31 formed on the rear end surface 3 b of the open / close cover 3 and the end surface 23 a of the side case portion 23 so as to be able to advance and retract. A main body side engaging claw 32. The main body side engaging claw 32 is urged in a direction protruding from the end surface 23a by a spring force of a spring member (not shown) arranged inside the apparatus main body. A slide button 33 for unlocking is attached to the outer side surface portion of the side case portion 23. Similarly, the lock mechanism of the other opening / closing cover 4 includes a main body side engaging claw 35, a case side engaging claw 36 and a slide button 37.

  FIG. 5A is a schematic perspective view showing the check processing device 1 with the opening / closing cover 3 removed, and FIG. 5B is a perspective view showing the inner surface of the removed opening / closing cover 3. Referring to FIGS. 3 to 5, the upstream side conveyance path portion 6 a defined by the opening / closing cover 3 includes, in order from the upstream side, a front side reading head 82 (first reading unit) and a back side reading head. 83 (second reading unit) is arranged. In this example, a back side read head 83, a magnetic head 84, and a printing mechanism 86 are mounted on the apparatus main body side, and a front side read head 82 is mounted on the open / close cover 3.

  The image sensor 83 a of the back side reading head 83 on the apparatus main body side is exposed on the main body side guide surface 21. A main body side rod 58 that protrudes toward the cover side guide surface 30 is formed in a flat trapezoidal shape at the upper edge portion of the main body side guide surface 21 that is positioned directly above the image sensor 83a. The main body side rod 58 is formed in a range wider than the width of the image sensor 83a in the transport direction.

  Similarly, the image sensor 82 a (reading position) of the front surface side reading head 82 on the side of the opening / closing cover 3 is exposed on the cover side guide surface 30. The image sensor 82a is disposed at a position adjacent to the upstream side in the transport direction with respect to the image sensor 83a (reading position) of the back side reading head 83. A cover side flange 59 protruding in a flat trapezoidal shape toward the main body side guide surface 21 is formed at the upper end edge portion of the cover side guide surface 30 positioned directly above the image sensor 82a. The cover side bar 59 is also formed in a range wider than the width of the image sensor 82a in the transport direction.

(Transport mechanism)
Next, FIG. 6 is an explanatory diagram showing a transport mechanism of the check reading device 1. The check supply unit 8 is provided with a feed roller 41 for sending the check 5 inserted in a stacked state here toward the check conveyance path 6 and a pressing member 42 for pressing the check 5 against the feed roller 41. Yes. The check delivery path 7 for sending the check 5 fed by the feed roller 41 to the check conveyance path 6 is separated as a separation mechanism for separating the check 5 one by one and sending it to the check conveyance path 6. A pad 43 and a separation roller pair including a separation roller 44 and a retard roller 45 are disposed. The feeding roller 41, the separation roller 44, and the pressing member 42 are driven by a common feeding motor 46.

  A transport mechanism that transports the check 5 fed by the feed roller 41 along the check transport path 6 includes a transport motor 47, a drive roller 48 attached to the rotation shaft of the transport motor 47, and the check transport path 6. Conveying rollers 51 to 57 disposed, and presser rollers 61 to 67 that are pressed against the respective conveying rollers 51 to 57 and rotated. The rotation of the presser roller 67 is transmitted to the discharge roller 69 via the transmission gear 68. Further, an endless belt 49 for transmitting the rotation of the transport motor 47 to the transport rollers 51 to 57 is provided. The endless belt 49 is driven from the driving roller 48 by a guide roller 71, a transport roller 56, a guide roller 72, a transport roller. It moves along an endless track returning to the driving roller 48 again via the roller 57, the conveying rollers 51 and 52, the guide rollers 73 and 74, and the conveying rollers 53, 54, and 55.

  In this example, the transport motor 47 of the transport mechanism rotates in both forward and reverse directions. As a result, the check 5 can move both upstream and downstream in the image sensors 82 a and 83 a of the reading heads 82 and 83. Details of the image reading operation in accordance with this movement will be described later.

  The conveyance rollers 51 to 54 are respectively disposed at the upstream end, the middle position, and the downstream portion of the upstream conveyance path portion 6a. The transport roller 55 and the transport roller 56 are disposed at an upstream portion and a middle portion of the downstream transport path portion 6b, and the transport roller 57 is disposed at a discharge port portion of the second check discharge portion 12. . The discharge roller 69 is disposed at the discharge port portion of the first check discharge unit 11.

A magnet 81 for magnetizing magnetic ink characters is disposed between the transport rollers 51 and 52 in the upstream transport path portion 6a. Between the transport rollers 52 and 53, a front side reading head 82 as a front side image reading device and a back side reading head 83 as a back side image reading device are arranged. That is, the transport roller 52 is disposed on the upstream side of the front surface side read head 82 and the read head 83, and the transport roller 53 is disposed on the downstream side.
A magnetic head 84 for reading magnetic ink characters and a pressing roller 85 for pressing the check 5 against the magnetic head 84 are disposed between the transport rollers 53 and 54.

  A printing mechanism 86 is disposed on the downstream side of the conveyance roller 56 in the downstream conveyance path portion 6b. The printing mechanism 86 is movable between a printing position for pressing the check 5 and a standby position retracted from the printing position by a driving motor (not shown). The printing mechanism 86 may be a stamp mechanism that prints on the check 5 by being pushed by a plunger.

  Various sensors are arranged in the check conveyance path 6 for check conveyance control. In the vicinity of the magnet 81, a paper length detector 91 for detecting the length of the check 5 to be sent out is arranged. In the vicinity of the reading position 84 </ b> A by the magnetic head 84, a double feed detector 92 for detecting that the check 5 is conveyed in an overlapping state is disposed. A jam detector 93 is disposed at a position on the front side of the transport roller 55. When the check 5 is continuously detected for a predetermined time or more by the jam detector 93, the check transport path 6 You can see that the paper is jammed with checks. A print detector 94 for detecting the presence or absence of the check 5 printed by the printing mechanism 86 is disposed at a position on the front side of the transport roller 56. Further, a discharge detector 95 for detecting the check discharged to the branch passages 8 and 9 branched from the check conveyance path 6 to the first check discharge unit 11 and the second check discharge unit 12. Is arranged.

  A switching plate 96 that is switched by a drive motor (not shown) is disposed at the upstream end of the branch passages 8 and 9. The switching plate 96 is for selectively switching the downstream end of the check conveyance path 6 with respect to the first check discharge unit 11 and the second check discharge unit 12 and guiding the check 5 to the selected discharge unit. .

(Control system)
FIG. 7 is a schematic block diagram showing a control system of the check reading apparatus 1. The control system of the check reading apparatus 1 includes a ROM and a RAM, and includes a control unit 100 that is configured around a CPU. The control unit 100 is connected to an upper host computer 103 via a communication cable 102. The host computer 103 includes input / output devices such as a display unit 103a, an operation unit 103b such as a keyboard and a mouse, and a check reading operation start command is input to the control unit 100 from the host computer 103 side.

  When the control unit 100 receives the reading operation start command, the controller 100 drives the delivery motor 46 and the transport motor 47 to feed the checks 5 one by one to the check transport path 6, and the sent checks 5 along the check transport path 6. To transport. The control unit 100 receives the surface image information, the back surface image information, and the magnetic ink character information of the check 5 read by the front surface side read head 82, the back surface side read head 83, and the magnetic head 84.

  When the check 5 is conveyed in the downstream direction and the image reading in the forward direction is completed, the control unit 100 reverses the conveyance motor 47 and reversely conveys the check 5 in the upstream direction. Similarly, in the reverse conveyance, the surface image information and the back surface image information of the check 5 read by the front surface side read head 82 and the back surface side read head 83 are input to the control unit 100.

  These pieces of information are supplied to the host computer 103. The host computer 103 includes a read image generation unit 104. The read image generation unit 104 performs image processing for appropriately combining and synthesizing image information read at the time of conveyance in the downstream direction and image information read at the time of conveyance in the upstream direction by a procedure described later. In addition, a character recognition process or the like is performed, and it is determined whether or not the reading is normally performed, and the determination result is supplied to the control unit 100. The control unit 100 controls driving of the printing mechanism 86 and the switching plate 96 based on the determination result. These processes can be performed not by the computer system 103 but by the control unit 100 of the check reading apparatus 1.

  The conveyance control of the check 5 by the control unit 100 is performed by detecting signals from the sheet length detector 91, the double feed detector 92, the jam detector 93, the print detector 94, and the discharge detector 95 arranged in the check conveyance path 6. Based on The control unit 100 is connected to an operation unit 105 including an operation switch such as a power switch formed in the device case 2.

(Image reading operation)
FIG. 8 is a schematic flowchart showing an image reading process procedure performed by the control unit 100 and the host computer 103 of the check reading apparatus 1. The image reading operation will be described according to this flowchart. First, when an operator inputs a reading start command from the operation unit 103 b of the computer system 103, the feeding roller 41 is rotated by the feeding motor 46 and the pressing member 42 is moved to press the check 5 against the feeding roller 41. As a result, the check 5 is sent out by the feeding roller 41. The checks 5 fed out to the check delivery path 7 are separated one by one by a separation mechanism (separation pad 43, separation roller 44 and retard roller 45) arranged in the check delivery path 7 to obtain a check conveyance path. 6 (step S11).

  When the leading end of the check 5 sent out by the paper length detector 91 (hereinafter, the downstream end of the check 5 being conveyed is referred to as “tip” and the upstream end is referred to as “terminal”) is detected. The transport motor 47 is driven, and the transport rollers 51 to 57 are rotationally driven. The sent check 5 passes through the transport roller 51 and forwards along the check transport path 6 from the transport roller 52 as the first transport unit (hereinafter, the direction from upstream to downstream is referred to as “front”, downstream The direction heading from the upstream to the upstream is referred to as “rearward”) (step S12).

  When the leading edge of the check 5 passes through the respective image sensors 82a and 83a of the front side reading head 82 as the first reading unit and the back side reading head 83 as the second reading unit, the front and back surfaces of the check 5 are detected. Image reading starts. When the leading end of the check 5 reaches the conveyance roller 53 as the second conveyance unit, the check 5 is held between the conveyance roller 53 and the pressing roller 63, and the check 5 is conveyed by the tensile force generated by the rotation of the conveyance roller 53. Reading is performed until the end of the check 5 passes the image sensors 82a and 83a (step S13).

  When image reading by forward conveyance (forward image reading) is executed, the control unit 100 transmits image information to the host computer 103 via the communication cable 102 (step S14). The host computer 103 receives the forward reading data (step S15).

  Next, the control unit 100 reverses the transport motor 47, and the transport rollers 51 to 57 also start reverse rotation. The check 5 in which the end is sandwiched between the transport roller 53 and the presser roller 63 facing the transport roller 53 is transported rearward along the check transport path 6 by the reverse rotation of the transport roller 53 (step S16).

  Then, when the end of the check 5 passes through the respective image sensors 82a and 83a of the front surface side read head 82 and the back surface side read head 83, image reading on the front surface and the back surface of the check 5 is started. When the end of the check 5 reaches the conveyance roller 52 that is the first conveyance unit, the check 5 is held between the conveyance roller 52 and the pressing roller 62, and the check 5 is conveyed even by a tensile force generated by the rotation of the conveyance roller 52. Reading is performed until the tip of the check 5 passes the image sensors 82a and 83a (step S17).

  When image reading by backward conveyance (reverse image reading) is executed, the control unit 100 transmits image information to the host computer 103 via the communication cable 102 (step S18). At this time, the control unit 100 stops the rotation of the transport motor 47 and temporarily stops the transport of the check 5 (step S19). The host computer 103 receives the backward reading data (step S20).

  The read image generation unit 104 generates read images for the front and back surfaces by using only the portions with less distortion of the forward direction read data and the reverse direction read data by a method described later (step S21). . The host computer 103 determines whether reading has been performed normally based on the acquired front surface image, back surface image, and magnetic ink character information.

  When the host computer 103 transmits the determination result (step S22), the control unit 100 that has received the determination (step S23) performs printing or discharging processing of the check 5 according to the reading determination result (step S24).

(Image processing operation)
FIG. 9 is a schematic diagram for explaining a paper feeding step and a state of image reading performed in each step. In both the forward direction read image and the reverse direction read image in the figure, the vertical axis means the main scanning position of the reading head, and the horizontal axis means the sub scanning position. Further, in the drawing, the front surface side read head 82 is omitted and only the back surface side read head 83 is shown, but a double-sided image can be read.

  FIG. 9A shows the starting point of the forward conveyance, and at this point, neither the forward reading image nor the backward reading image is generated. FIG. 9B shows the moment when the force applied to the document during forward conveyance changes from the pushing force to the pulling force, and a forward reading image is generated to some extent. Up to this point, reading is performed in a state where an extrusion force is applied, and the image is distorted (or highly likely) for the reason described above. A thin shaded portion in the figure indicates a region where distortion is generated (or the possibility is high).

  The forward conveyance ends at the time shown in FIG. From the time point (b) to the state (c), reading is performed in a state where a tensile force is applied. That is, the latter half of the image is an image with relatively little distortion. Note that the dark shaded portion in the figure indicates a region where no distortion occurs.

FIG. 9D shows the start time of the reverse conveyance, and at this time, the reverse read image has not been generated yet.
FIG. 9E shows the moment when the force applied to the document during reverse conveyance changes from the pushing force to the pulling force, and a reverse reading image is generated to some extent. Up to this point, reading is performed in a state where an extrusion force is applied, and the image is distorted (or highly likely).

At the time shown in FIG. 9F, the reverse conveyance is completed. From the time point (e) to the state (f), reading is performed in a state where a tensile force is applied. That is, the latter half of the image is an image with relatively little distortion.
Since the forward read image and the reverse read image are obtained by the above-described reciprocal reading operation, as shown in FIG. 9G, it is only necessary to extract, combine, and synthesize the respective regions where no distortion occurs.

It should be noted that images can be combined and synthesized by the following procedure using a known method.
(1) Reading is performed so that the lengths of the forward reading image and the backward reading image coincide with each other, the portion read by extruding the original is deleted from the forward reading image, and the corresponding area is removed from the backward reading image. Supply.
(2) Reading is performed so that the lengths of the forward reading image and the backward reading image are the same, and a portion read by extruding the original is deleted from the backward reading image, and the corresponding area is removed from the forward reading image. Supply.

  In the above cases (1) and (2), the document is transported on condition that the document has a uniform and sufficient paper thickness and the same amount of document deflection occurs in the forward and reverse transport paths. By matching the speed and the sampling period in the forward direction and the reverse direction, it is possible to read so that the lengths of the forward direction read image and the reverse direction read image match. Further, if the coordinate axis of the read image is X or Y, either coordinate axis is proportional to the time t. Therefore, the time when the document is changed by the conveying roller 53 and the pressing roller 63 (or the conveying roller 52 and the pressing roller 62). From t0, the coordinates on the image can be calculated. Therefore, the portion read by extrusion from the read image can be deleted based on the coordinates corresponding to time t0.

(3) Reading is performed so that the lengths of the forward reading image and the backward reading image coincide with each other, and the portions read by the extrusion of the original are deleted in each of the forward reading image and the backward reading image, thereby overlapping. The parts to be synthesized are synthesized while taking an average value at a ratio according to the position.
(4) The document conveyance speed and the sampling cycle are matched in the forward direction and the reverse direction, and the portion read by pushing out the document is deleted in each of the forward direction read image and the reverse direction read image. The displacement is estimated from the portion that has the possibility of overlapping by pattern matching, position correction is performed, and the overlapping portion is synthesized while taking an average value at a ratio according to the position.

In the case of (3) above, the “overlapping portion” is determined from the device dimensions and the document change timing. FIG. 10A is a schematic plan view of the check conveyance path, and FIG. 10B is a schematic side view of the check conveyance path. As shown in FIG. 10, the transport roller 52 and the presser roller 62 are each separated into two in the main scanning direction, and a transmission type document detection sensor comprising a projector 91 (92) and a light receiver 92 (91) is interposed between them. Install. Similarly, the conveyance roller 53 and the pressing roller 63 are separated into two in the main scanning direction, respectively, and a transmission type document detection sensor including a projector 93 (94) and a light receiver 94 (93) is provided therebetween. The pressing roller 96 that presses the conveyed document toward the reading head 83 is also divided into two.
The conveyance roller 52 and the pressing roller 62 push out the original from the upstream side and the difference in timing when the original passes between the original detection sensor pair 91, 92 and the original detection sensor pair 93, 94. Accumulation of strain due to stress can be calculated. An “overlapping portion” can be obtained from the accumulated distortion.

In the case of (4), “position correction” is performed on the assumption that the positional deviation between the forward read image and the reverse read image can be approximated by the affine transformation T. FIG. 11 is a diagram for explaining position correction between a forward direction read image and a reverse direction read image.
As shown in FIG. 11B, first, the distorted images A1 and B1 from the forward direction read image A and the reverse direction read image B are discarded. Next, as shown in FIG. 11C, the forward-direction read image A is blocked, and a position shift is obtained by block matching at a portion that may overlap. As shown in FIG. 11D, in order to align the two images, a coordinate conversion formula is obtained by using a least square method of block displacement.
Assuming that the coordinate values (X _A , Y _A ) of the forward direction read image A and the coordinate values of the corresponding reverse direction read image B are (X _B , Y _B ), the forward direction read image A and the reverse direction read image B If the positional deviation can be approximated by the affine transformation T, the relationship between the coordinate values can be expressed by the following transformation formula 1.

座標変換のアフィン行列の自由度は６であり、１個のブロックマッチの結果につき拘束式が２つ得られるので、重心が直線状に並ばない３個のブロックマッチを行えば、座標変換の行列を求めることができる。４個以上のブロックマッチを行った場合は、最小二乗法を用いる。

The degree of freedom of the affine matrix for coordinate transformation is 6, and two constraint equations are obtained for each block match result. Therefore, if three block matches whose centroids are not arranged in a straight line are performed, a matrix for coordinate transformation is obtained. Can be requested. When four or more block matches are performed, the least square method is used.

Further, after the position correction in (3) and (4) above, the forward read image A and the reverse read image B can be combined by the following method.
As shown in FIG. 12, the pixel value of each coordinate of the forward direction read image A is I _A (X _A , Y _A ), and the pixel value of the reverse direction read image B corresponding to each coordinate of the forward direction read image A is Let I _BA (X _A , Y _A ). At this time, the composite image I ′ (X _A , Y _A ) can be expressed by the following Expression 2 using the coefficient k (X _A , Y _A ).

When the right end of the forward direction read image A is the corresponding position X _{B1 on} the reverse direction read image B and the left end of the reverse direction read image B is X _B0 , the weighting coefficient is expressed by the following relational expression 3.

(5) Reading is performed without paying particular attention to the lengths of the forward reading image and the backward reading image, and the portions read by extruding the original in each of the forward reading image and the backward reading image are deleted, and the stress Align and synthesize using image features in the vicinity of the switch.
For example, alignment is performed based on the luminance characteristics of each pixel in the vicinity where the stress changes.
Also in this case, the coordinates on the image can be calculated from the time t0 when the document is changed by the conveying roller 53 and the pressing roller 63 (or the conveying roller 52 and the pressing roller 62). Based on the coordinates corresponding to the time t0, the portion read by pushing out the original from the read image may be deleted.

(Other embodiments)
In the present embodiment, it is described that the entire image of the check 5 is read not only when the sheet is conveyed in the forward direction but also when the sheet is conveyed in the reverse direction. You can also For example, in reverse conveyance, when the magnetic ink character string 5A printed on the surface 5a of the check 5 is read, the reading operation may be terminated, and the forward transfer may be switched to the discharge process. If the description area of the magnetic ink character string 5A corresponding to each check standard can be obtained, the conveyance amount necessary for reading the magnetic ink character string 5A during reverse conveyance can be calculated. Therefore, only the calculated transport amount is transported during reverse transport, and the reading process is performed only during that time, and then the forward transport is switched.
The processing time for reciprocal reading can be shortened while increasing the reading accuracy of important information portions such as the magnetic ink character string 5A.

  Note that the method of (5) described above can be applied to synthesize the forward read image (entire image of the check 5) and the reverse read image (partial image including the magnetic ink character string 5A).

  The present invention can be similarly applied to an image reading system for processing sheet-like media other than checks such as checks, bills, and bills. For example, the present invention can be applied to an image processing apparatus such as a printer or a scanner.

As described above, in the image reading system according to the present embodiment, the check processing system includes the reading unit (reading head 82 or 83) that reads the image on the recording medium, and the first conveyance provided upstream from the reading unit. Part (conveying roller 52 and pressing roller 62), a second conveying part (conveying roller 53 and pressing roller 63) provided downstream from the reading unit, and the recording medium is conveyed in the forward direction from the upstream side to the downstream side. When the image is read, the image read by the reading unit when the second conveying unit sends the recording medium downstream from the reading position and the image conveyed by conveying the recording medium from the downstream side to the upstream side in the reverse direction. A read image generation unit 104 that generates a read image of the recording medium based on an image read by the reading unit when the first transport unit sends the recording medium upstream from the reading position when reading the recording medium. To.
The image is read by reciprocating the check 5 in the forward direction and the reverse direction, and only the undistorted area where the reading is performed while receiving the tensile force is used as a read image. Thus, it is possible to generate a read image without distortion throughout.

In addition, the check processing apparatus according to the present embodiment includes a first reading unit (front-side reading head 82) that reads an image on the first surface of a recording medium, and a second reading unit that reads an image on the second surface of the recording medium. (Back side read head 83).
When the CIS type image sensor is adopted as the reading head, it is necessary to bring the document into close contact with the image sensor side. Therefore, as shown in FIG. 10, it is necessary to install a pressing roller 96 on the opposite surface side of the reading head 83. . Further, for reasons such as the possibility of detecting CIS light on the opposite surface, the front-side read head 82 and the rear-side read head 83 are inevitably installed in positions that are not opposed to each other. . For this reason, the check 5 does not necessarily bend in the vicinity of the read heads 82 and 83 in the same manner. In this case, in reading only in the forward direction, a difference occurs in the distortion generated on the read image on the front surface and the back surface, and there may be a difference in the length of the read image. However, according to the present embodiment, it is possible to obtain a read image having no distortion on both the front surface and the back surface, and thus it is possible to prevent a difference in length between the read image on the front surface and the read image on the back surface.

1 is an external perspective view of a check processing apparatus to which the present invention is applied. It is a schematic diagram which shows the structure of the surface of a check. It is an external appearance perspective view of a check processing device in a state where an opening / closing cover is opened. It is a top view of the check processing device in a state where the opening / closing cover is opened. FIG. 4 is a perspective view of the check processing device with one open / close cover removed, and a perspective view showing the open / close cover removed. It is explanatory drawing which shows the conveyance mechanism of a check processing apparatus. It is a schematic block diagram which shows the control system of a check processing apparatus. It is a schematic flowchart which shows the image reading process procedure by the control part of a check reading apparatus. FIG. 5 is a schematic diagram for explaining a paper feeding step and a state of image reading performed in each step. (A) is a schematic plan view of the check conveyance path, and (b) is a schematic side view of the check conveyance path. It is a figure explaining the position correction of a forward direction read image and a reverse direction read image. It is a figure explaining the method to synthesize | combine a forward direction read image and a reverse direction read image. FIG. 4 is a schematic diagram for explaining a state where a document passes in front of a reading head of an image scanner.

Explanation of symbols

1: check processing device, 5: check, 6: check transport path, 47: transport motor, 48: drive roller, 49: endless belt, 51-57: transport roller, 61-67: presser roller, 82: front side reading Head, 83: Back side reading head, 100: Control unit, 103: Host computer, 104: Reading image generation unit

Claims (4)

A reading unit for reading an image on a recording medium;
A first transport unit provided upstream of the reading unit;
A second transport unit provided downstream of the reading unit;
When reading the image by transporting the recording medium from the upstream side to the downstream side in the forward direction, the image read by the reading unit when the second transport unit sends the recording medium downstream from the reading position; When the recording medium is conveyed in the reverse direction from the downstream to the upstream to read the image, the first conveyance unit reads the recording medium from the reading position to the upstream side, and the image that is read by the reading unit. An image reading system comprising: a read image generation unit configured to generate a read image of the recording medium. When reading an image conveyed in the reverse direction, the reading unit stops reading processing when reading an image formed in a predetermined area of the recording medium,
The image reading system according to claim 1, wherein the first conveyance unit and the second conveyance unit change conveyance in the reverse direction of the recording medium in a forward direction. An image reading system comprising: a reading unit that reads an image on a recording medium; a first conveyance unit provided upstream from the reading unit; and a second conveyance unit provided downstream from the reading unit. An image reading method in
A first reading step of reading the image by conveying the recording medium from upstream to downstream in the forward direction;
A second reading step of reading the image by conveying the recording medium in the reverse direction from downstream to upstream;
The image read by the reading unit when the second conveying unit sends the recording medium downstream from the reading position in the first reading step, and the first conveying unit in the second reading step. An image generation step of generating a read image of the recording medium based on an image read by the reading unit when the recording medium is sent upstream from a reading position. In the second reading step,
4. The image reading method according to claim 3, wherein the reading process is stopped when an image formed in a predetermined area of the recording medium is read, and the reverse conveyance of the recording medium is changed to the forward direction.

Images