Image reading system

Abstract

To remove punch holes without losing object information such as characters.SOLUTION: An image reading system includes image reading means 70 for reading image information of a document, document hole detection means 74 for detecting holes from the read image read by the image reading means 70, luminance information calculation means for calculating luminance information radially from the center of the hole on the basis of the hole in the document detected by the document hole detection means 74, and colored area determination means 75 for determining whether there is a colored area different from the background color of the document around the hole from the luminance information obtained by the luminance information calculation means. The area determined to be a colored area by the colored area determination means 75 is corrected to the background color.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an image reading system including an image reading device that reads an image of a document, and more particularly to an image processing program, an image processing device, and an image processing method for removing images corresponding to punch holes formed in a document. [Background technology]

[0002] A technology has been proposed for detecting and removing portions of an image of a document read by an image reading device that correspond to holes (hereinafter referred to as "punch holes") formed in the document by, for example, a punch.

[0003] For example, in the image reading device described in Patent Document 1, when a punch hole is formed in pressure-sensitive paper, the punch hole image and the color that will be applied in response to pressure being applied to the periphery of the punch hole are calculated based on the pixels in a rectangular area corresponding to the punch hole image.Then, a fill target area is set from the calculated color, and the punch hole and the surrounding color are removed with the fill color. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6376024 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned Patent Document 1, the color around the punch hole is calculated in a rectangular area, and if it differs from the background color of the document, the area is filled in to remove the color around the punch hole and its surroundings. However, there is a risk that information such as characters near the punch hole may also be determined to be subject to removal and removed, which could result in a loss of information. [Means for solving the problem]

[0006] In view of the above, an image reading system according to the present invention comprises: an image reading means for reading image information of a document; a document hole detection means for detecting holes in the image read by the image reading means; a luminance information calculation means for calculating luminance information radially from a center side of the hole based on the hole in the document detected by the document hole detection means; a colored area determining means for determining whether or not there is a colored area around the hole that is different in color from the background color of the document based on the luminance information obtained by the luminance information calculating means; Equipped with The colored area determination means corrects the area determined to be a colored area to the background color. Effect of the Invention

[0007] According to the present invention, it is possible to remove only the color formed around the punched holes, and to leave object information such as characters. [Brief description of the drawings]

[0008] [Figure 1] 1 is a partial cross-sectional view illustrating a schematic configuration of a document transport device (image reading device) according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a block diagram of a document conveying device (image reading device) according to an embodiment of the present invention; [Diagram 3] FIG. 1 is a block diagram of an image processing unit according to an embodiment of the present invention. [Figure 4] 1 is a flowchart showing a process for removing punched holes and areas surrounding the holes according to an embodiment of the present invention; [Diagram 5] FIG. 13 is an explanatory diagram of a process for determining a removal area for a punch hole and a peripheral area of ​​the hole according to an embodiment of the present invention; [Figure 6] 1 is a flowchart of a process after object area detection according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are examples for carrying out the present invention, and the present invention is not limited to the following embodiments. The present invention should be appropriately modified or changed depending on the configuration of the device in which the present invention is used and various conditions, without departing from the spirit of the present invention.

[0010] [First embodiment] First, a document transport device according to a first embodiment of the present invention will be described.

[0011] 1 is a partial cross-sectional view showing the schematic configuration of an image reading device according to a first embodiment of the present invention. In this embodiment, the image reading device is configured as a system, and an embodiment will be described in which the image reading device is composed of an image reading device A and an external device 200. However, the image reading device may be configured as a single device, or may be configured as a system in which each component is composed of different devices.

[0012] <Device configuration> The image reading device A is a device that conveys one or more conveying media S loaded on a loading platform 1 one by one through a route RT into the device, reads the images, and discharges the media to a discharge tray 2 serving as a loading member. The conveying media S to be read are, for example, postcards, office paper, checks, business cards, cards, and other sheets, and may be thick or thin sheets. Examples of cards include insurance cards, driver's licenses, and credit cards. The conveying media S also include booklets such as passports. When a booklet is the target, a holder can be used. By placing a booklet in an open state in a transparent holder and placing it on the loading platform 1, the booklet is conveyed together with the holder, and the image can be read.

[0013] <Paper Feed> A first transport unit 10 is provided as a feeding mechanism that feeds the transport medium S along the path RT. In this embodiment, the first transport unit 10 includes a feed roller 11 and a separation roller 12 arranged opposite the feed roller 11, and transports the transport medium S on the mounting table 1 one by one in the transport direction D1. A driving force is transmitted to the feed roller 11 from a drive unit 3 such as a motor via a transmission unit 5, and the feed roller 11 is driven to rotate in the direction of the arrow in the figure (the positive direction for transporting the transport medium S along the path RT). The transmission unit 5 is, for example, an electromagnetic clutch, and connects and disconnects the driving force from the drive unit 3 to the feed roller 11.

[0014] <Drive unit> In this embodiment, for example, the transmission unit 5 that connects the drive unit 3 and the feed roller 11 is in a state in which the driving force is normally transmitted, and the driving force is interrupted when the transport medium S is reversed or stopped. When the transmission of the driving force is interrupted by the transmission unit 5, the feed roller 11 is in a state in which it can rotate freely. Note that such a transmission unit 5 does not need to be provided when the feed roller 11 is driven in only one direction.

[0015] <Separated structure> The separation roller 12, which is disposed opposite the feed roller 11, is a roller for separating the transport media S one by one, and is in contact with the feed roller 11 with a constant pressure. To ensure this state of contact, the separation roller 12 is provided so as to be able to swing and is configured so as to be biased toward the feed roller 11. A driving force is transmitted to the separation roller 12 from the drive unit 3 via a torque limiter 12a, and the separation roller 12 is driven to rotate in the direction of the solid arrow (the opposite direction to the forward direction of the feed roller 11).

[0016] Since the transmission of driving force is restricted by the torque limiter 12a, the separation roller 12 rotates in a direction (indicated by a dashed arrow) that rotates together with the feed roller 11 when in contact with the feed roller 11. As a result, when multiple conveying media S are conveyed to the pressure contact portion between the feed roller 11 and the separation roller 12, two or more conveying media S except for one are blocked so as not to be conveyed downstream.

[0017] In this embodiment, the separation mechanism is composed of the separation roller 12 and the feed roller 11, but such a separation mechanism is not necessarily required, and any feed mechanism that sequentially feeds the transport medium S one by one to the path RT will suffice. In addition, when a separation mechanism is provided, instead of a configuration such as the separation roller 12, a separation pad that applies friction to the transport medium S may be pressed against the feed roller 11 to provide a similar separation function.

[0018] <Conveyor structure> The second transport section 20, which serves as a transport mechanism located downstream of the first transport section 10 in the transport direction, includes a drive roller 21 and a driven roller 22 driven by the drive roller 21, and transports the transport medium S transported from the first transport section 10 downstream. A driving force is transmitted to the drive roller 21 from a drive section 4 such as a motor, and the drive roller 21 is driven to rotate in the direction of the arrow in the figure. The driven roller 22 is pressed against the drive roller 21 with a constant pressure, and rotates together with the drive roller 21. The driven roller 22 may be configured to be biased against the drive roller 21 by a biasing unit (not shown) such as a spring.

[0019] The third transport section 30, which is located downstream of the second transport section 20 in the transport direction, includes a drive roller 31 and a driven roller 32 driven by the drive roller 31, and transports the transport medium S transported from the second transport section 20 to the discharge tray 2. In other words, the third transport section 30 functions as a discharge mechanism.

[0020] A driving force is transmitted from a driving unit 4 such as a motor to the driving roller 31, and the driving roller 31 is rotated in the direction of the arrow in the figure. The driven roller 32 is pressed against the driving roller 31 with a constant pressure, and rotates together with the driving roller 31. The driven roller 32 may be configured to be biased against the driving roller 31 by a biasing unit (not shown) such as a spring.

[0021] The discharge tray 2 on which documents are stacked is pivotally supported via a first hinge 101 provided below the image reading device A so as to be rotatable relative to the image reading device A. The device is also made up of a first discharge tray 2a on the first hinge 101 side and a first extension tray 2b, a second extension tray 2c, and a third extension tray 2d connected to the tip side of the first discharge tray 2a.

[0022] <Image reading structure and control> Here, in the image reading device A of this embodiment, since the image is read by the image reading unit 70 arranged between the second conveying unit 20 and the third conveying unit 30, the second conveying unit 20 and the third conveying unit 30 convey the conveyed medium S at a constant speed. By always setting the conveying speed to be equal to or higher than the conveying speed of the first conveying unit 10, it is possible to reliably prevent the following conveyed medium S from catching up with the preceding conveyed medium S. For example, in this embodiment, the conveying speed of the conveyed medium S by the second conveying unit 20 and the third conveying unit 30 is controlled to be faster than the conveying speed of the conveyed medium S by the first conveying unit 10.

[0023] Furthermore, even if the conveying speed of the conveying medium S by the second conveying section 20 and the third conveying section 30 and the conveying speed of the conveying medium S by the first conveying section 10 are the same, it is also possible to form a minimum gap between the preceding conveying medium S and the succeeding conveying medium S by controlling the drive section 3 to intermittently shift the timing at which the feed of the succeeding conveying medium S begins.

[0024] <Double feed detection> The double feed detection sensor 40 disposed between the first conveying section 10 and the second conveying section 20 is an example of a detection sensor (a sensor that detects the behavior or state of sheets) for detecting when conveying media S such as paper have come into close contact with each other due to static electricity or the like and passed through the first conveying section 10 (i.e., when there is a double feed state in which the conveying media S are conveyed overlapping each other). Various types of double feed detection sensor 40 can be used, but in this embodiment, it is an ultrasonic sensor that includes an ultrasonic transmitter 41 and a receiver 42, and detects double feed based on the principle that the attenuation of ultrasonic waves passing through conveying media S such as paper differs between when the conveying media S are conveyed overlappingly and when they are conveyed one by one.

[0025] <Registration sensor> The medium detection sensor 50, which is disposed downstream in the transport direction from the double feed detection sensor 40, is an example of a detection sensor (sensor that detects the behavior and state of a sheet) disposed upstream of the second transport section 20 and downstream of the first transport section 10 on the upstream side of the transport path RT, and detects the position of the transported medium S transported by the first transport section 10, more specifically, whether or not the end of the transported medium S has reached or passed the detection position of the medium detection sensor 50. Various types of medium detection sensor 50 can be used, but in this embodiment, it is an optical sensor that includes a light emitting section 51 and a light receiving section 52, and detects the transported medium S on the principle that the received light intensity (received light amount) changes when the transported medium S arrives at or passes through.

[0026] In this embodiment, the medium detection sensor 50 is provided downstream of and in the vicinity of the double feed detection sensor 40 so that the medium S has reached a position where the double feed can be detected by the double feed detection sensor 40 when the leading edge of the medium S is detected by the medium detection sensor 50. The medium detection sensor 50 is not limited to the optical sensor described above, and may be, for example, a sensor (such as an image sensor) capable of detecting the end of the medium S, or a lever-type sensor protruding into the path RT. A plurality of sensors may also be provided in a direction perpendicular to the transport direction to detect that the medium is slanting relative to the transport path.

[0027] A medium detection sensor 60 separate from the medium detection sensor 50 is disposed upstream of the image reading unit 70. This is an example of a downstream detection sensor disposed downstream of the second conveying unit 20, and detects the position of the conveyed medium S conveyed by the second conveying unit 20. Various types of medium detection sensor 60 can be used, but in this embodiment, like the medium detection sensor 50, it is an optical sensor that includes a light-emitting unit 61 and a light-receiving unit 62, and detects the conveyed medium S based on the principle that the received light intensity (amount of received light) changes when the conveyed medium S arrives or passes through it. In this embodiment, the medium detection sensors 50 and 60 are disposed on the upstream and downstream sides of the second conveying unit 20 in the conveying direction, respectively, but only one of them may be used.

[0028] <Arrangement of CIS> The image reading unit 70 downstream of the medium detection sensor 60 optically scans, for example, converts it into an electrical signal, and reads it as image data, and includes a light source such as an LED, an image sensor, a lens array, etc. inside. The image reading unit 70 is a contact image sensor (CIS) unit. Here, the image reading unit 70 is a CIS unit, but for example, it may be a unit using a CCD as an image sensor, and the type of the image sensor is not limited. In the case of this embodiment, the image reading units 70 (hereinafter synonymous with CIS) are arranged one on each side of the path RT (70a, 70b) and read the front and back surfaces of the transport medium S. However, it may be configured to arrange only one on one side of the path RT and read only one side of the transport medium S. Also, in this embodiment, the image reading units 70 are arranged to face each other on both sides of the path RT, but for example, they may be arranged at intervals in the direction of the path RT.

[0029] <Explanation of Block Diagram> With reference to FIGS. 2 and 3, the basic configuration of this image reading apparatus will be described. FIG. 2 is a block diagram of the control unit of the image reading apparatus A.

[0030] The image reading apparatus A basically includes an image reading unit (front) 70a, an image reading unit (back) 70b, an image control unit 71, a control unit 80, a transport unit 86, and a detection sensor unit 87. The image reading unit (front) 70a and the image reading unit (back) 70b turn on the light emitting element at the timing instructed by the image control unit 71 and perform one-line scanning. The image control unit 71 instructs the reading timing of the image reading unit (front) 70a and the image reading unit (back) 70b according to an instruction from the control unit 80, performs processes such as A / D conversion and shading correction on the image signals output from the image reading unit (front) 70a and the image reading unit (back) 70b, and sends them to the subsequent buffer memory 72.

[0031] Buffer memory 72 has a capacity for temporarily storing at least several lines of image data, and the image data sent from image control unit 71 is written into free space in buffer memory 72 that does not already have data to be sent to sending unit 73. In other words, the area in which the image data sent to sending unit 73 was written becomes a free area (free space) for writing new image data output from image control unit 71.

[0032] Image control unit 71 monitors the free space of buffer memory 72, and when the free space of buffer memory 72 falls below a predetermined value, notifies control unit 80 of that fact. Sending unit 73 has a function of communicating with external device 200 such as a host PC outside image reading device A, and transmits image data upon request from external device 200. The image data transmitted to external device 200 is processed by image processing unit 78 inside external device 200, and then stored in image data storage unit 79 using a storage device such as a hard disk drive. Furthermore, transmission and reception between external device 200 and control unit 80 is performed via sending unit 73.

[0033] Here, the external device 200 is further provided with an operation unit 201 that allows instructions to be input to the image reading device A, and a display unit 202 that displays information related to image reading processing.

[0034] 3 is a diagram showing details inside the image processing unit 78. The image processing unit 78 receives image data sent from the sending unit 73, and detects punch hole images in the received image data using the punch hole image detection unit 74. Based on the results of the punch hole image detection unit, an area determination unit 75 determines areas near the punch holes that differ from the background color of the document and determine the area to be removed. After the area to be removed in the image data has been determined, the image data is stored in the image data storage unit 79 with the punch holes and surrounding images removed (filled in with the background color).

[0035] The control unit 80 comprehensively controls the operation of the entire image reading device A. The transport unit 86 is made up of a plurality of drive units and transmission units, etc., shown in Fig. 1, and is driven and controlled by instructions from the control unit 80. The detection sensor unit 87 is made up of sensors such as the medium detection sensors 50 and 60 and the double feed detection sensor 40, shown in Fig. 1. The control unit 80 grasps the current state and position of the document based on information from these sensors.

[0036] Details of the control of the image processing unit 78 of this embodiment will be described with reference to the control flow of FIG. 4 and the explanatory diagram of FIG.

[0037] Image data read by the image reading device A of this embodiment is sent to an image processing unit 78 of the external device 200 via a sending unit 73. In the present invention, the acquired image is converted to gray and handled as a luminance value in order to detect the removal area of ​​the punch hole and the surrounding image.

[0038] In order to detect the punch hole and the removal area of ​​the surrounding image, the center coordinates of the punch hole are set (S101). The punch hole can be detected from the image read from the front and back of the document. For example, if the reading background member provided in a position facing the image reading unit is black, the punch hole image is acquired in black. If the position of this acquired black image is at the same coordinates on the front and back of the read image, it can be determined that it is a punch hole image, and the punch hole can be detected.

[0039] The center coordinates of the punch holes are calculated from the punch hole image detected in this way, and the process of confirming the removal area of ​​the punch hole image is started. Figure 5 shows an example of a punch hole image to explain this process.

[0040] The center of the punch hole is C, the outer periphery of the punch hole is P, the outer periphery of the colored area around the punch hole is Q, an example of the radially extending direction of checking the removal area is indicated by a and b, the outer periphery of the punch hole image is indicated by ai and bi, and the ends of the removal area in the document are indicated by a-ii and b-ii. In addition, the letter "A" is located outside of b-ii, and the end of "A" is indicated by b-iii. The lower part of Fig. 5 shows the change in luminance in the directions a and b.

[0041] For the punch hole image, a direction from the center C of the punch hole to check for the removal area is set (S102). For example, the image luminance value of the target coordinates is checked in the direction from the center C of the hole to a to determine whether it is a punch hole image area (S103). Specifically, punch holes in an image scanned from a black background member will be a black image with a low luminance value, so a threshold value can be set in advance from the luminance value when the black background member is scanned.

[0042] If the brightness value of the target coordinates is below the threshold (Y in S103), it is determined to be a punch hole area, the current coordinates are registered as a punch hole area, and the coordinates to be confirmed are changed (S104). If the brightness value of the target coordinates is above the threshold (N in S103), it is determined not to be a punch hole area, and the process moves to the next step. If there is a color outside the punch hole area in the acquired image that is different from the background color of the document, the color of that area must also be removed. For example, in the case of pressure-sensitive paper, color can be transferred due to pressure applied around the holes when punching holes.

[0043] The luminance value of the attached color is low near the punch holes, and the further away from the punch holes the higher the luminance value becomes. This attached color is unnecessary for the image information and is therefore removed. To detect attached color outside the punch hole area, it is checked whether the luminance value of the target coordinates is higher (brighter) than the luminance value of the previous coordinates (S105), and if the luminance value is higher (Y in S105), it is determined to be an area to be removed, the current coordinates are registered as an area to be removed, and the coordinates to be checked are then changed (S106).

[0044] By checking the luminance value at each coordinate in this way, the area outside the punch hole area where color has adhered to the background color (for example, a-ii in this example) is detected. The next coordinate after the end of the colored area, a-ii, is not colored and is the background color of the document (for example, white). When the luminance value is checked at the next coordinate after this coordinate, the luminance value of this coordinate will be the same as the previous coordinate (N in S105), so the next process is to check whether the luminance value of that coordinate is lower than the previous coordinate (S107).

[0045] If the brightness value is lower than the previous coordinate (Y in S107), the current coordinate is registered as a region to be removed, and then the coordinate to be confirmed is changed (S108). The brightness value of the next coordinate is confirmed, and if there are consecutive pixels with low brightness values ​​(Y in S110), it is determined that the information at that coordinate may be an object such as text information or a line drawing, and the coordinate is registered as a region to be confirmed as an object (S111). After registration, the coordinate registered in S108 as a region to be removed (the coordinate before the brightness value changed to a lower value) is stored as the removal region coordinate (S112). Note that in S110, the number of consecutive pixels with low brightness values ​​may be checked to a predetermined number of 3 or more.

[0046] On the other hand, if the brightness value is the same as or higher than the previous coordinates in S107 (N in S107), the coordinates are stored as removal area coordinates (S109). This process is performed in all directions from the center C of the punch hole (S113), and if the check is not complete (N in S113), the check direction is changed and the process continues (S114). If the check in all directions is complete (Y in S113), the removal area detection process is completed (S115). Here, checking in all directions may mean that the outer periphery of the punch hole is evenly divided into a preset number, and the check in all directions is completed when the above check is completed for all of the divided numbers.

[0047] When these removal area detection processes are completed, the image processing unit 78 performs a process to change the areas determined to be removal areas to an arbitrary color such as the background color of the document, and generates an image from which the colors attached to the punch holes and their surroundings have been removed. By performing this process, punch holes and their surrounding colors can be detected reliably, and furthermore, the areas of object information such as text information (object areas) can be left without being included in the removal area, preventing the loss of information.

[0048] Second Embodiment In this embodiment, when an object area such as text information is detected in the processing flow of the first embodiment, OCR processing is performed to determine whether the information is text information and to perform correction processing to the background color of the document.

[0049] As shown in the flow of Fig. 6, if an object area is detected (Y in S202) as a result of performing the removal area detection process (S201), OCR processing is performed on the detected object area (S203). If an object area is not detected (N in S202), the process is completed (S207).

[0050] If the OCR process is performed and it is determined to be text information (Y in S204), the process is completed as it is (S207). If it is not determined to be text information (N in S204), it is confirmed whether to perform correction process on the area (S205). If it is determined to be unnecessary information (Y in S205), the target area is corrected to the background color (S206) and the process is completed (S207). As an example of a method for determining unnecessary information in S205, if the result of the OCR process in S203 is not determined to be text information, it may be set so that it is automatically determined to be unnecessary information, or an operator of the image reading device (external device 200) may be informed to select whether to leave the area as it is or to correct it to the background color (unnecessary information), and a determination may be made based on the result.

[0051] If it is determined that the information is necessary and correction processing is not to be performed (N in S205), the target area is left as is and processing is completed (S207). By performing this processing, it is possible to determine whether the object information present around the punch hole is information that should be left, such as characters, or information that can be removed, and to perform appropriate processing.

[0052] The present invention is not limited to the above-described embodiments, and various modifications can be applied within the scope of the invention. For example, the color of the background member arranged opposite the image reading unit of the image reading device is described as black, but the device may be arranged with a white background. Even in this case, punch holes can be detected by detecting a shadow on the edge of the punch hole or a circular shape from the outline of the colored portion attached to the periphery, and the present invention can be applied. [Explanation of symbols]

[0053] A Image reader S Transport medium 1. Placement table 2 Output tray 3, 4 Drive unit 5 Transmission section 11 Feed roller 12 Separation roller 21, 31 Drive roller 22, 22 driven roller 40 Double feed detection sensor 50, 60 Media detection sensor 70, 70a, 70b Image reading unit 71 Image control section 72 Buffer Memory 73 Transmission Department 74 Punch hole image detection unit 75 Area determination section 78 Image Processing Section 79 Image data storage section 80 Control section 81 CPU 82 Memory section 83 Operation section 84 Communications Department 85 Interface section 86 Actuator 87 Sensors 201 Operation section 202 Display section

Claims

1. an image reading means for reading image information of a document; a document hole detection means for detecting holes in the image read by the image reading means; a luminance information calculation means for calculating luminance information radially from a center side of the hole based on the hole in the document detected by the document hole detection means; a colored area determining means for determining whether or not there is a colored area around the hole that is different in color from the background color of the document based on the luminance information obtained by the luminance information calculating means; Equipped with an image reading system comprising: a color corrector for correcting an area determined to be a colored area by said colored area determining means to said background color;

2. the colored region determination means includes a character information detection means for detecting the presence of object information such as characters or line drawings in the colored region; 2. The image reading system according to claim 1, wherein among the areas determined as the colored areas by said colored area determining means, areas other than the areas determined as the character information by said character information detecting means are corrected to a background color.

3. 3. The image reading system according to claim 2, wherein said character information detection means determines that a portion containing successive pixels with low luminance values ​​in said colored area is object information such as a character or a line drawing.

4. 3. The image reading system according to claim 2, further comprising a character information determining unit that performs OCR processing on the character information area and determines whether the information in the target area is text.

5. 4. The image reading system according to claim 3, further comprising a notification means for notifying an operator that, if the character information detection means does not determine that the area is character information, the operator can choose to leave the area as is or to correct it to a background color.

Images