JP2010135964A - Driver of image reading apparatus, and image reading method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a distortion of a reading image because of a minute position gap of an image caused by a change of a document carrier speed from a setting speed, and to prevent the distortion of the reading image caused by a carrier roller deterioration or the like. <P>SOLUTION: A driver 110 of a check processing device 1 has a first image sensor 82a and a second image sensor 82b set away from each other in a direction of a carrier of a check 5 and reading an image of the check 5, and roller driving motors 46 and 47 carrying the check 5 at a preset setting speed in a direction of a carrier and passing the check through two image sensors 82a and 82b. The driver has an image correction unit 111 detecting a carrier speed when the check 5 actually passes through two image sensors 82a and 82b, and extending and correcting a reading image based on a difference between the detected carrier speed and the setting speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a driver and an image reading method for controlling an operation of an image reading apparatus that reads an image relating to a medium such as a check while conveying the medium in a conveyance path.

  A check processing apparatus for processing checks is known as a medium processing apparatus for processing sheet-like media. In the check processing device, 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. (For example, refer to Patent Document 1).

  By the way, in an image scanner that reads an image, a document is conveyed in front of a fixed reading head. However, the read image is distorted at a certain length after the leading edge of the document passes the reading position. There was a case.

This will be specifically described. When the original moves from the conveying roller in front of the reading head to the inner conveying roller, the following two kinds of different forces are applied to the original.
(1) The document is nipped by a conveyance roller in front of the head, and is conveyed forward when the 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 at the back of the head.
(2) When the leading edge of the document reaches the position of a roller immediately behind the head and the roller rotates, the document is further conveyed forward. A tensile force is applied to the document between the two rollers that sandwich the reading head. This situation continues until the end of the document passes the read head.

Japanese Patent Application Laid-Open No. 2008-211154 (page 4 to page 6, FIG. 1)

  FIG. 13 is a schematic diagram for explaining how a document passes in front of the image sensor 83 a of the reading head 83. In the conveyance state from the state (a) to reaching (c) in the figure, the force that the document receives in the vicinity of the reading head is the force pushed by the conveyance roller 52 and the pressing roller 62 and the friction in the document path. Therefore, the document may be slightly bent (see (b) in the figure). When this deflection occurs, the document speed in the vicinity of the reading head is not constant, so that the read image may be distorted.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to prevent a read image from being distorted due to a minute positional deviation of an image caused by a change in the document conveyance speed from a set speed. It is another object of the present invention to prevent distortion of a read image due to deterioration of a conveyance roller.

The present invention that can solve the above-described problems is provided with a plurality of reading sensors that are installed apart from each other in the conveyance direction of the recording medium and read an image of the recording medium, and convey the recording medium at a preset setting speed. A driver for an image reading apparatus comprising: a conveyance unit that conveys the plurality of reading sensors in a direction;
An image that detects a conveyance speed when the recording medium actually passes through the plurality of reading sensors, and expands and contracts the read image based on a difference between the conveyance speed detected by the speed detection unit and the set speed. It has a correction part.

According to the above configuration, since the read image is expanded or contracted based on the difference between the detected actual conveyance speed and the set speed, correction is performed so that the speed distribution is uniform. Therefore, an image without distortion can be acquired. As a result, the recognition rate in OCR (optical character recognition) or the like is improved, a highly accurate reading determination can be performed, and the determination result can be provided to the image reading apparatus.
Further, the difference between the conveyance speed and the set speed necessary for image correction can be easily obtained from the deviation of the read images by the plurality of reading sensors. Therefore, it is possible to easily acquire an image without distortion, perform highly accurate reading determination, and provide the determination result to the image reading apparatus.

  In the present invention, the image correction unit divides the read image into strips along a line parallel to the main scanning direction of the reading sensor, and the read image is sub-scanned by the reading sensor for each divided area. The correction is performed by expanding and contracting in the direction.

  According to the above configuration, even if the conveyance speed partially changes during conveyance of the recording medium, correction is performed for each of the divided areas so that the velocity distribution is uniform. No image can be acquired. Thereby, the recognition rate in OCR or the like is improved, and it is possible to perform highly accurate reading determination and provide the determination result to the image reading apparatus. Furthermore, since the velocity distribution is corrected so as to be uniform for each of the divided areas, it is possible to absorb the deviation of the conveyance speed due to the aging deterioration of the conveyance roller.

  In the present invention, the image correction unit divides the read image into a grid pattern, and performs correction by expanding and contracting the read image in the sub-scanning direction and the main scanning direction for each divided region. Features.

  According to the above configuration, even when the conveyance speed partially changes during the conveyance of the recording medium, the correction is made two-dimensionally so that the velocity distribution is uniform, so there is no distortion. Images can be acquired. Thereby, the recognition rate in OCR or the like is improved, and more accurate reading determination can be performed.

Further, the present invention capable of solving the above-described problems is provided with a plurality of reading sensors that are installed apart from each other in the conveyance direction of the recording medium and read an image of the recording medium, and the recording medium at a preset setting speed. An image reading method by an image reading apparatus comprising: a conveying unit that conveys the plurality of reading sensors through the conveying direction;
An image correction step of detecting a conveyance speed when the recording medium actually passes through the plurality of reading sensors, and expanding and contracting and correcting the read image based on a difference between the detected conveyance speed and the set speed. It is characterized by.

  According to the above configuration, correction is performed so that the velocity distribution is uniform, so that an image without distortion can be acquired. As a result, the recognition rate in OCR (optical character recognition) or the like is improved, and highly accurate reading determination can be performed.

  In the image reading method of the present invention, the image correction step divides the read image into strips along a line parallel to the main scanning direction of the read sensor, and reads the read image for each divided area. The correction is performed by expanding and contracting in the sub-scanning direction of the sensor.

  According to the above configuration, even when the conveyance speed partially changes during conveyance of the recording medium, correction is performed so that the velocity distribution is uniform, so an image without distortion is acquired. be able to. 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, the image correction step divides the read image into a lattice shape, and corrects the read image by expanding and contracting in the sub-scanning direction and the main scanning direction for each divided region. It is characterized by performing.

  According to the above configuration, even when the conveyance speed partially changes during the conveyance of the recording medium, the correction is made two-dimensionally so that the velocity distribution is uniform, so there is no distortion. Images can be acquired. Thereby, the recognition rate in OCR or the like is improved, and more accurate reading determination can be performed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an image reading apparatus driver and an image reading method according to the present invention will be described with reference to the drawings. In the following, a check processing apparatus is illustrated as an embodiment of the image reading apparatus, and an embodiment in which a driver that controls the operation of the check processing apparatus is mounted on a host computer that is communicably connected to the check processing apparatus will be described.

(Overall configuration of check processing device)
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.

  The check 5 has a magnetic ink character string 5 </ b> A printed in the long side direction at the lower end portion of the surface 5 a thereof. 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. 2 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. 3 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. 2 and 3, 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. 4A is a schematic perspective view showing the check processing device 1 with the opening / closing cover 3 removed, and FIG. 4B is a perspective view showing the inner surface of the removed opening / closing cover 3. Referring to FIGS. 2 to 4, a front-side reading head 82 and a back-side reading head 83 are arranged in order from the upstream side in the upstream conveyance path portion 6 a defined by the opening / closing cover 3. . 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.

  An image sensor 83a, which is a first image sensor unit, and an image sensor 83b, which is a second image sensor unit, are arranged at close intervals on the back side read head 83 on the apparatus main body side. In addition, a main body side rod 58 protruding toward the cover side guide surface 30 is formed in a flat trapezoidal shape at the upper edge portion of the image sensors 83a and 83b.

  Similarly, an image sensor 82a that is a first image sensor unit and an image sensor 82b that is a second image sensor unit are arranged at close intervals on the front surface side read head 82 on the opening / closing cover 3 side. . In addition, a cover side rod 59 protruding in a flat trapezoidal shape toward the main body side guide surface 21 is formed at the upper edge portion of the image sensors 82a and 82b. The front side read head 82 is disposed at a position adjacent to the upstream side in the transport direction with respect to the back side read head 83.

(Transport mechanism)
The check supply unit 8 is provided with a feeding roller for sending the check 5 inserted in a stacked state toward the check conveyance path 6 and a pressing member for pressing the check 5 against the feeding roller (both shown) (Omitted). A check delivery path 7 for sending the check 5 fed by the feed roller to the check transport path 6 is a separation pad as a separation mechanism for separating the check 5 one by one and sending it to the check transport path 6. A separation roller pair including a separation roller and a retard roller is disposed (both not shown). The feeding roller, separation roller, and pressing member are driven by a common feeding motor 46 (see FIG. 5).

  A transport mechanism that transports the check 5 fed by the feed roller along the check transport path 6 includes a transport motor 47 (see FIG. 5), a drive roller attached to the rotation shaft of the transport motor 47, and the check transport path 6. And a plurality of press rollers that are pressed against each of the transport rollers and rotated together (all of which are not shown). Since the rotation of the presser roller is transmitted to the discharge roller (not shown) via the transmission gear, the check 5 is appropriately sent to the first check discharge unit 11 or the second check discharge unit 12 along the conveyance path 6. Be transported.

(Control system)
FIG. 5 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. The host computer 103 also includes a driver 110 that controls the operation of the check processing device 1, and the image correction unit 111 is formed by executing the driver 110.

  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.

  These pieces of information are supplied to the host computer 103. The image correction unit 111 of the host computer 103 detects a shift between both read images that occurs when the first image sensor 82a and the second image sensor 82b read the check 5 while synchronizing them according to a procedure described later. If the deviation causes a difference from a deviation at a predetermined speed set in advance, image correction processing is performed to expand and contract the read image based on the difference. Thereafter, character recognition processing or the like is performed on the corrected read image, 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 host computer 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. 6 is a schematic flowchart showing an image reading processing procedure. The image reading operation will be described according to this flowchart. First, when the operator inputs a reading start command from the operation unit 103b of the host computer 103, the check 5 is sent to the check conveyance path 6 by the feed motor 46 (step S11). In the following, the image reading of the first image sensor 82a and the second image sensor 82b of the front surface side read head 82 will be described, but similar image reading is also performed by the back surface side read head 83 and transmitted to the host computer 103. The

  When the check 5 reaches the position of the front side reading head 82 by conveyance, reading of the image is started (step S12). Since the first image sensor 82a and the second image sensor 82b are arranged at a slight interval (for example, 0.5 inches), the start of reading is shifted by this interval.

  The control unit 100 transmits the read data read by the first image sensor 82a and the second image sensor 82b to the upper host computer 103 via the communication cable 102 (step S13).

  When the host computer 103 receives the read data (step S14), the image correction unit 111 executes image processing according to a procedure described later (step S15), and generates a corrected read image (step S16). The host computer 103 determines whether reading has been performed normally based on the corrected front image, back image, and magnetic ink character information.

  When the host computer 103 transmits the determination result (step S17), the control unit 100 that has received the determination (step S18) prints or discharges the check 5 according to the reading determination result (step S19).

(Image processing operation)
FIG. 7 is a schematic diagram for explaining the relationship between the arrangement of the image sensor of the check reading apparatus and the conveyance speed of the check. In the present embodiment, the image sensors 82a and 82b having a reading frequency of 10 times per second are arranged at intervals of 0.5 inches. The images acquired from both sensors are substantially the same image, and both expand and contract depending on the document conveyance speed. If the positions of the lines scanned at the same time are matched, the difference in the position of the image sensor appears as a translational shift (image shift) of the pattern on the image.

[Example 1]
FIG. 8 is a diagram schematically illustrating how the image shift changes according to the document conveyance speed (in the following description, pix represents a pixel). In the figure, the case where the document conveyance speed is 1.2 inches / second, 1.0 inches / second, and 0.8 inches / second is illustrated. For example, if the preset check speed is 1.0 inch / second (image displacement = 5 pix) but the obtained image misalignment is 4 pix, the conveyance speed is actually high (1. 2 inches / second), it is determined that the acquired read image is contracted. Therefore, an image without distortion can be generated by performing correction for expanding the acquired image at an appropriate ratio. On the other hand, if the difference between the two acquired images is 6 pix, it is determined that the acquired read image is expanded. Therefore, if correction is performed to contract at an appropriate ratio, a distortion-free image is generated. Can do.

  Since there is a correspondence relationship between the document feed speed, the image shift amount, and the amount of expansion / contraction required for correction, if the amount of shift can be determined, the amount of expansion / contraction required for correction can be determined. For estimation of the amount of deviation, a cross-correlation function or a block matching method (SSD: Sum of Square Difference or NCC: Normalized Cross-Correlation) can be used. . When the block matching method is employed, for example, a position in the image B where a specific position in the image A has moved is obtained. A block centered on a pixel at a specific position is used as a template, a certain range is examined with a pixel at the same position as the specific pixel of image A in image B, and the pixel corresponding to the central pixel at the position where SSD is the smallest And it is sufficient. This process is performed for all the pixels of the image A.

FIG. 9 is a flowchart showing a procedure of image correction processing. Here, a method using a so-called cross-correlation function will be described. The cross-correlation function is used to confirm the similarity between two signals, arrays (vectors). It can be seen that there is a correlation if the result of the function array is all 1, a non-correlation if all are zero, and a negative correlation if all are -1.
The host computer 103 calculates a cross-correlation function between the two acquired images (step S21). Next, a parameter that maximizes the calculated cross-correlation function is calculated, and an image shift is estimated (step S22). Next, the image is expanded or contracted according to the ratio between the image shift estimated in step S22 and the ideal image shift (step S23). Finally, the image (image B) acquired by the second image sensor 82b is shifted so as to match the position of the image (image A) acquired by the first image sensor 82a, and is combined into one image ( Step S24). According to this correction process, when there is uniform distortion in the entire image (for example, expansion and contraction of the read image due to deterioration of the transport roller), it is possible to obtain an image without distortion by correcting them.

  Here, since the two image sensors 82a and 83a mounted on the check reading apparatus 1 of the present embodiment have different positions, the time for reading the same point on the document is different. For this reason, the images read by the two image sensors 82a and 83a are always shifted in position. A state where there is a predetermined amount of shift is an ideal state, and the “ideal image shift” is a shift of an image in an ideal state. That is, when the document is not bent, bent, slipped, or the like, more specifically, the first image sensor 82a is used when there is no unevenness in the motor feed rate and the document is completely conveyed by a uniform linear motion. Refers to the deviation between the image read by and the image read by the second image sensor 83a.

  For example, if the target document feed speed is 1 cm / sec, the attachment interval between the image sensors 82a and 83a is 1 cm, and the sampling cycle is 60 Hz, the ideal image shift is 60 pix.

[Example 2]
FIG. 10 is a diagram schematically showing how the image shift changes according to the document conveyance speed when the conveyance speed changes in the middle of the check conveyance. When the check conveyance speed changes from moment to moment due to deterioration or abnormality of the apparatus, different distortions occur in the read image for each portion. In such a case, as shown in FIG. 10A, it is possible to appropriately correct distortion by dividing the read image into blocks and detecting the image shift as obtained in the first embodiment for each block. it can.

  For example, as shown in FIG. 10B, when the preset set speed is 1.0 inch / second (image displacement = 5 pix), the first block is determined to have an image displacement of 4 pix and a high conveyance speed. Therefore, it is understood that correction for expanding the image of the block may be performed. In the next block, since the image shift is 5 pix and there is no difference in the conveyance speed, the image of the block is not corrected. Further, since the next block has an image shift of 6 pix, it is determined that the conveyance speed is low, and it is understood that correction for contracting the image of the block may be performed.

  FIG. 11 is a flowchart showing the procedure of the image correction process described above. First, the host computer 103 divides the image (image A) acquired by the first image sensor 82a out of the two acquired images into strip-shaped blocks (step S31). Next, block matching is performed for each block, and an image shift amount is obtained by the above-described procedure (step S32). Next, for each block, the image is expanded or contracted according to the ratio between the image shift obtained in step S32 and the ideal image shift (step S33). Next, the corrected blocks are connected to generate an image (step S34).

  The above procedure is also executed for the image (image B) acquired by the second image sensor 82b to correct distortion (step S35). Finally, the image (image B) acquired by the second image sensor 82b. Are shifted so as to match the position of the image (image A) acquired by the first image sensor 82a, and are combined into one image (step S36). According to this correction processing, when distortion changes in an image (for example, expansion and contraction of a read image due to partial deterioration of a roller), it is possible to obtain an image without distortion by correcting them.

[Example 3]
FIG. 12 is a diagram schematically showing how the image shift changes according to the document conveyance speed when the conveyance speed changes two-dimensionally during the check conveyance. When the conveyance speed of a check changes two-dimensionally from time to time due to deterioration or abnormality of the apparatus or defective check setting, a different distortion occurs in the scanned image. In such a case, as shown in FIG. 12A, the read image is divided into a grid pattern, and distortion is obtained by two-dimensionally detecting the image shift as obtained in the first embodiment for each block. It can be corrected appropriately.

  Specifically, based on the shift amount of each block calculated two-dimensionally, the so-called nearest neighbor method using the value of the pixel closest to the position to be obtained as it is, or four pixels around the position to be obtained By interpolating using a so-called bilinear method or the like that obtains the weighted average value of the values, a vector map of the shift amount between blocks or pixels is obtained (FIG. 12B). Based on this deviation vector map, first, starting from the center point of the leftmost block, a line along the deviation vector is drawn (FIG. 12 (c)), and the document speed is integrated on each line, Then, the position where the displacement matches one pixel unit is calculated, and the points are connected with a line (FIG. 12D). When the area surrounded by this line is transformed into a square for each block and then connected and spread, an image with corrected distortion is obtained. For the correction of each block, projective transformation, affine transformation, or the like may be used.

(Other embodiments)
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.

  In this embodiment, the case where two image sensors 82a and 82b are mounted has been described. However, the number of sensors is not limited to two, and three or more image sensors may be mounted. In this case, the SSSD: Sum of SSD proposed by multiple baseline stereo is used for calculating the positional deviation of each part of the image, or two adjacent sets of images obtained from a plurality of acquired images are generated. More accurate estimation can be performed, for example, by calculating an average value.

  As described above, the check processing apparatus 1 according to the present embodiment is the first image sensor 82a (or the image sensor 83a) for reading the image of the check 5 installed close to the conveyance direction at a predetermined interval. And a second image sensor 82b (or image sensor 83b), a conveyance motor 47 that conveys the check 5 at a preset speed, and passes the first and second image sensors 82a and 82b. . In addition, the host computer 103 detects a deviation between both read images that occurs when the first and second image sensors 82a and 82b read the check 5 while synchronizing, and the deviation is a preset setting. When there is a difference from the deviation in speed, the image correction unit 111 performs correction by expanding and contracting the read image based on the difference. As a result, correction is performed so that the velocity distribution is uniform, so that an image without distortion can be acquired.

  The image correction unit 111 divides the read image into strips along a line parallel to the main scanning direction of the image sensor, and corrects the read image by expanding and contracting in the sub-scanning direction of the image sensor for each divided area. Do. Therefore, even when the conveyance speed changes during the conveyance of the check, correction is performed so that the velocity distribution is uniform, so that an image without distortion can be acquired.

  In addition, the image correction unit 111 divides the read image into a lattice shape, and corrects the read image by expanding and contracting in the sub-scanning direction and the scanning axis direction for each divided region. Therefore, even when the conveyance speed changes during the conveyance of the check, correction that makes the velocity distribution uniform is performed two-dimensionally, so that an image without distortion can be acquired. Thereby, the recognition rate in OCR or the like is improved, and more accurate reading determination can be performed.

1 is an external perspective view of a check processing apparatus to which the present invention is applied. 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 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. It is a schematic diagram for demonstrating the relationship between arrangement | positioning of the image sensor of a check reader, and the conveyance speed of a check. FIG. 6 is a diagram schematically illustrating a state in which an image shift changes according to a document conveyance speed. 7 is a flowchart illustrating a procedure of image correction processing (first embodiment). FIG. 10 is a diagram schematically illustrating a state in which an image shift changes according to a document conveyance speed when a conveyance speed changes in the middle of a check conveyance. 10 is a flowchart illustrating a procedure of image correction processing (second embodiment). FIG. 10 is a diagram schematically illustrating a state in which an image shift changes according to a document conveyance speed when the conveyance speed changes two-dimensionally in the middle of check conveyance. 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 conveyance path, 46: delivery motor, 47: conveyance motor, 82: front side reading head, 82a: first image sensor, 82b: second image sensor, 83 : Back side image sensor, 83a: first image sensor, 83b: second image sensor, 100: control unit, 103: host computer

Claims (6)

A plurality of reading sensors that are installed apart from each other in the conveyance direction of the recording medium and read an image on the recording medium, and the recording medium is conveyed in the conveyance direction at a preset speed and passed through the plurality of reading sensors. A driver of an image reading apparatus including a conveyance unit,
An image correction unit that detects a conveyance speed when the recording medium actually passes through the plurality of reading sensors, and expands and contracts the read image based on a difference between the detected conveyance speed and the set speed; A driver of an image reading apparatus characterized by the above.   The image correction unit divides the read image into strips along a line parallel to the main scanning direction of the reading sensor, and expands / contracts the read image in the sub-scanning direction of the reading sensor for each divided region. The driver of the image reading apparatus according to claim 1, wherein correction is performed.   The image correction unit divides the read image into a lattice shape, and corrects the read image by expanding and contracting the read image in the sub-scanning direction and the main scanning direction for each divided region. A driver of the image reading apparatus according to 1. A plurality of reading sensors that are installed apart from each other in the conveyance direction of the recording medium and read an image on the recording medium, and the recording medium is conveyed in the conveyance direction at a preset speed and passed through the plurality of reading sensors. An image reading method by an image reading apparatus comprising a transport unit,
An image correction step of detecting a conveyance speed when the recording medium actually passes through the plurality of reading sensors, and expanding and contracting and correcting the read image based on a difference between the detected conveyance speed and the set speed. An image reading method using an image reading apparatus.   In the image correction step, the read image is divided into strips along a line parallel to the main scanning direction of the reading sensor, and the read image is expanded and contracted in the sub-scanning direction of the reading sensor for each divided region. The image reading method according to claim 4, wherein correction is performed.   The image correction step divides the read image into a lattice shape, and performs correction by expanding and contracting the read image in the sub-scanning direction and the main scanning direction for each divided region. 5. An image reading method by the image reading device according to 4.

Images