Image reading device and image reading system

Abstract

To improve the reading accuracy for reading large-sized paper.SOLUTION: An image reading device includes a reading unit that reads a first recording medium, an imaging unit that images a second recording medium having a size larger than that of the first recording medium, an adjustment unit that moves or rotates the imaging unit, a storage unit that stores a second image showing a marker that serves as a reference for correcting the first image showing the imaging result of the imaging unit, and an image processing unit that generates a third image by correcting the first image on the basis of the second image.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and an image reading system. [Background technology]

[0002] There is known a technique for reading an image formed on a recording medium such as paper (hereinafter, an example will be described in which the recording medium is paper). In particular, there is known a technique for reading an image formed on paper that is larger than the document table provided in an image forming apparatus.

[0003] Specifically, a technique for connecting the bases of a device in which the main body and base are used separately is known. To connect the bases, a positioning part and a positioned part are provided, and by combining the positioning part and the positioned part, the base can be used depending on the application. In this way, a technique for realizing a user-friendly presentation device is known (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional techniques may have poor reading accuracy, i.e., the conventional techniques have a problem in that they are not capable of reading large-sized paper with sufficient accuracy.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to improve the reading accuracy when reading large-sized paper. [Means for solving the problem]

[0006] In order to solve the above problems, an image reading device according to one aspect of the present invention comprises: a reading unit that reads the first recording medium; an imaging unit that images a second recording medium having a size larger than the first recording medium; an adjustment unit that moves or rotates the imaging unit; a storage unit that stores a second image showing a marker that serves as a reference for correcting a first image showing a result of imaging by the imaging unit; an image processing unit that corrects the first image based on the second image to generate a third image; Equipped with. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the reading accuracy when reading large size paper. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the overall configuration of an image reading apparatus. [Figure 2] FIG. 2 illustrates an example of a hardware configuration. [Figure 3] FIG. 10 is a diagram illustrating an example of overall processing. [Figure 4] FIG. 10 is a diagram showing a first example of a second image. [Figure 5] FIG. 10 is a diagram showing a first example of a fourth image. [Figure 6] FIG. 10 is a diagram illustrating a first example of correction. [Figure 7] FIG. 10 is a diagram showing a second example of a second image. [Figure 8] FIG. 10 is a diagram showing a second example of the fourth image. [Figure 9] FIG. 10 is a diagram illustrating a second example of correction. [Figure 10] FIG. 1 illustrates an example of the configuration of an image reading system. [Figure 11] FIG. 10 is a diagram showing an example of a display on a display unit. [Figure 12] FIG. 2 is a diagram illustrating an example of a functional configuration. [Figure 13] FIG. 10 is a diagram illustrating a modified example of the overall processing. DETAILED DESCRIPTION OF THE INVENTION

[0009] Specific examples will be described below with reference to the accompanying drawings. Note that the embodiment is not limited to the specific examples described below. The following description will be given using an example in which the recording medium is paper.

[0010] [First embodiment] [Overall configuration example] 1 is a diagram showing an example of the overall configuration of an image reading device, for example, a Multi Function Peripheral (hereinafter referred to as "MFP1") shown in FIG.

[0011] The MFP 1 is equipped with a camera 2 in its Automatic Document Feeder (hereinafter referred to as "ADF"). The ADF rotates when opened or closed by the user. Therefore, the mechanism adjusts the movement or rotation of the camera 2 by moving the ADF. Note that the adjustment may also be performed using other mechanical parts, actuators, etc.

[0012] [Hardware configuration example] 2 is a diagram showing an example of a hardware configuration. For example, an MFP 1 has a hardware configuration including a camera 2, a central processing unit (hereinafter referred to as a “CPU 3”), a scanner 4, a storage device 5, and an interface 6.

[0013] The camera 2 is an example of an image capturing device, and captures an image of the paper 10 placed within the angle of view. Therefore, the camera 2 includes an optical sensor, a lens, and the like.

[0014] The CPU 3 is an example of a calculation device and a control device.

[0015] The scanner 4 is configured to provide an image reading function of reading an image formed on the paper 10 by performing a scanning process on the placed paper 10 with an image reading element.

[0016] The storage device 5 is a main storage device, an auxiliary storage device, or the like.

[0017] The interface 6 is a device for sending and receiving data to and from the outside.

[0018] As described above, when the MFP 1 and the camera 2 are integrated, devices used for processing can be shared, which reduces costs.

[0019] The MFP 1 may also be configured to send and receive data to and from an information processing device via the interface 6 and execute all or part of the processing in the cloud, etc. With such a configuration, the MFP 1 can reduce the amount of processing by the CPU 3 when processing images read via the scanner 4 or camera 2, and execute the processing using external resources.

[0020] Note that the hardware configuration of the MFP 1 is not limited to that shown in Fig. 2. For example, the MFP 1 may further include an arithmetic unit, a control unit, a storage unit, an input unit, an output unit, an image forming unit, and peripheral devices.

[0021] The MFP 1 uses the scanner 4 and the camera 2 depending on the size of the paper 10. For example, if the paper 10 is A3 or smaller in size, the MFP 1 reads the image by scanning it with the scanner 4. On the other hand, if the paper 10 is a larger size such as A0, the MFP 1 uses the camera 2 to capture the image.

[0022] However, the size at which the scanner 4 and camera 2 are switched is determined by the size and settings of the MFP 1. Also, there may be a size at which either the scanner 4 or the camera 2 can be used.

[0023] The size of the paper 10 that the scanner 4 is to read is smaller than the size of the paper 10 that the camera 2 can photograph.

[0024] This is because the scanner 4 has a structure in which an optical element scans the paper 10 to read an image, and the scannable range of the optical element is restricted by the structure and size of the MFP 1.

[0025] On the other hand, camera 2 can capture images of areas beyond the scannable range of scanner 4 by adjusting the focal length and angle of view using a combination of lenses.

[0026] That is, the MFP 1 has a configuration that provides a function of reading an image formed on the paper 10 by scanning, and a configuration that provides a function of reading an image formed on the paper 10 by photographing.

[0027] Hereinafter, a recording medium of a size that can be read by the scanner 4 will be referred to as the "first recording medium." On the other hand, a recording medium of a size that can be photographed by the camera 2 will be referred to as the "second recording medium." In other words, the second recording medium is larger in size than the first recording medium.

[0028] As shown in Fig. 1, when photographing paper 10 with camera 2, MFP 1 uses large size document table 11. Specifically, large size document table 11 is placed on a document table or the like. Then, when photographing paper 10 with camera 2, paper 10 is placed on large size document table 11. Furthermore, large size document table 11 has a mechanism that allows it to be detached from the document table by suction or the like.

[0029] [Variation using a separate object as the large-size document holder] Large size document table 11 may be an object separate from MFP 1 and camera 2. When large size document table 11 is an object separate from MFP 1 in this way, large size document table 11 can be larger than the size of MFP 1. Therefore, when large size document table 11 is used, it is possible to handle large size paper 10.

[0030] It is desirable that the large size document table 11 be configured to electrostatically attract the paper 10. Specifically, the large size document table 11 generates static electricity by passing a weak current through the surface that attracts the paper 10. That is, the large size document table 11 is equipped with a power supply device that passes a weak current through the surface that attracts the paper 10. When an operation such as pressing a switch is performed, a current output from the power supply device flows through the large size document table 11, generating static electricity.

[0031] By generating static electricity in this way, the large size document table 11 can attract the paper 10. Therefore, even if the large size document table 11 is in a so-called "wall-mounted" position, the paper 10 can be attracted, and the paper 10 can be prevented from shifting.

[0032] [Overall processing example] FIG. 3 is a diagram showing an example of overall processing. Below, the overall processing will be explained by dividing it into "pre-processing" and "execution processing." "Pre-processing" is processing that is performed before "execution processing." Therefore, "pre-processing" and "execution processing" do not have to be executed consecutively. In other words, there may be an interval between "pre-processing" and "execution processing" because other processing is performed between them. Furthermore, if the conditions are the same, "pre-processing" only needs to be executed once, and if the "pre-processing" is executed under the same conditions after it has been executed, "pre-processing" may be omitted. Below, the overall processing will be explained in which "pre-processing" and "execution processing" are executed consecutively.

[0033] Hereinafter, an image showing the result of capturing an image formed on paper 10 will be referred to as a "first image." For example, the first image may show a blueprint, a figure, a character, a pattern, or a combination of these. On the other hand, an image including a marker that serves as a reference for correcting the first image will be referred to as a "second image." Details of the second image will be described later.

[0034] The image obtained by correcting the first image is called the "third image." Furthermore, an image of the same marker as the second image taken through a lens or the like is called the "fourth image."

[0035] [Pre-processing example] In step S0301, the MFP 1 stores the second image. That is, the second image is input in advance to the MFP 1. Thereafter, when a fourth image showing a similar marker is input, the MFP 1 can generate correction data.

[0036] In step S0302, the MFP 1 adjusts the camera 2. For example, the user operates the camera 2 by moving and rotating it so that the paper 10 is included in the angle of view. In this way, the position and attitude of the camera 2 are adjusted.

[0037] In step S0303, the MFP 1 captures an image of the marker. For example, the marker is formed on the large size platen 11 in advance. Then, when the large size platen 11 is placed, the camera 2 captures an image of the marker formed on the large size platen 11 to generate a fourth image.

[0038] In step S0304, the MFP 1 generates correction data.

[0039] The correction data indicates the content of the correction process for making the captured image ideal, i.e., free of distortion and curved lines. In other words, the correction data indicates the content of image processing for comparing the second image showing the marker in an ideal state with the fourth image, which is an actual image of the marker, to determine how to correct the first image to generate the third image. With such correction data, it is possible to correct the expansion / contraction of each location on the scale, distortion, and the distance between markers, etc., based on the marker data.

[0040] In particular, the correction data preferably includes image processing content for correcting distortions, such as curvature, that the first image has, but the correction data may also include image processing content for correcting chromatic aberrations, etc.

[0041] [Execution processing example] The execution process is performed after the correction data is generated in the pre-processing.

[0042] In step S0305, the MFP 1 captures an image of the paper 10. In this way, a first image is generated.

[0043] In step S0306, the MFP 1 corrects the first image based on the correction data to generate a third image.

[0044] 4 is a diagram showing a first example of the second image. In the figure, the center in the horizontal direction is indicated by a "horizontal center line C1." Similarly, in the figure, the center in the vertical direction is indicated by a "vertical center line C2."

[0045] For example, the second image is configured with markers such as scales. The length of one scale is measured in advance and input to the MFP 1. In this way, if the length of one scale is known, the MFP 1 can easily determine the scale.

[0046] Furthermore, it is desirable that the marker be a point-symmetrical figure. Specifically, in the example shown in Fig. 4, the second image is a figure that is bilaterally symmetrical about a horizontal center line C1 and vertically symmetrical about a vertical center line C2.

[0047] The distortion of camera 2 is not necessarily uniform due to lens manufacturing errors, etc. Therefore, by making the markers point-symmetrical, it becomes easier to see where distortion has occurred and it can be corrected with high precision.

[0048] Fig. 5 is a diagram showing a first example of the fourth image. When the marker shown in Fig. 4 is photographed, for example, the fourth image shown in Fig. 5 is generated.

[0049] 4 and 5, the fourth image has a shape in which the upper part of the image is shrunk inward compared to the second image due to distortion and the tilt of camera 2. That is, in the first example, in an ideal state, the second image would be an entire rectangular image, whereas the fourth image is a trapezoidal image with a shorter upper part due to distortion, etc.

[0050] FIG. 6 shows a first example of correction. FIG. 6(A) is similar to FIG. 5, i.e., shows the fourth image. Meanwhile, FIG. 6(B) shows the image after correction. As indicated by the dashed line, the correction is image processing that deforms the upper part of the fourth image. By performing this correction, an image with less distortion as shown in FIG. 6(B), i.e., an image closer to the second image, can be generated from the distorted fourth image shown in FIG. 6(A).

[0051] By performing such correction, the MFP 1 can generate the third image from the first image.

[0052] 7 is a diagram showing a second example of the second image. The marker may have the configuration shown in the figure.

[0053] Fig. 8 is a diagram showing a second example of the fourth image. Below, an example will be described in which the marker shown in Fig. 7 is photographed as shown in Fig. 8. If the camera 2 is inclined relative to the paper 10, the fourth image shown in Fig. 8 is generated.

[0054] Figure 9 shows a second example of correction, where Figure 9(A) shows the same as Figure 8, i.e., the fourth image, while Figure 9(B) shows the image after correction.

[0055] By performing such a correction, an image with less tilt shown in FIG. 9(B), that is, an image closer to the second image, can be generated from the tilted fourth image shown in FIG. 9(A).

[0056] The marker is not limited to the markers described above, and may be, for example, a graphic such as a cross.

[0057] As described above, when the camera 2 is installed in the ADF, the positional relationship between the camera 2 and the paper 10 can be adjusted by opening and closing the ADF. However, the position and attitude of the camera 2 may be adjusted by a mechanism other than the ADF. Therefore, the mechanism and degree of freedom for adjusting the camera 2 are not important.

[0058] If there is variation in the positional relationship between the camera 2 and the paper 10, i.e., the position at which the camera 2 photographs the paper 10 and the angle of the camera 2 relative to the paper 10, errors will occur in the magnification, etc. Similarly, variations in the precision of the lens of the camera 2 will also cause errors in the magnification, etc.

[0059] Furthermore, if the position and attitude of the camera 2 changes, the distance between the camera 2 and the paper 10 also changes, which tends to cause variations in the size of the image, etc.

[0060] Therefore, even when reading large-sized paper using these cameras 2, the MFP 1 can improve reading accuracy if the image can be corrected.

[0061] [Second embodiment] Compared with the first embodiment, the second embodiment is different in that it is an image reading system having a photographing device and an image reading device connected to the photographing device via a network. Specifically, the image reading system has the following configuration.

[0062] 10 is a diagram showing an example of the configuration of an image reading system. Compared to the first embodiment, the image reading system 100 differs in that the MFP 1 and the camera 2 are separate objects.

[0063] The MFP 1 and camera 2 are connected via a network. Therefore, image data captured by the camera 2 is sent to the MFP 1 via the network.

[0064] If the MFP 1 and the camera 2 are separate objects, that is, if the camera 2 is not built into the MFP 1, the camera 2 can be moved freely.

[0065] In particular, it is desirable that the distance between the camera 2 and the paper 10 be finely adjustable. Specifically, it is desirable that the paper 10 be photographed as large as possible within the range that fits within the angle of view of the camera 2. In other words, the optimal distance for the camera 2 is as close as possible to the paper 10 within a range that allows the entire paper 10 to be captured. If the paper 10 is photographed at such an optimal distance, the resolution of the image of the paper 10 can be increased. Therefore, it is desirable that the MFP 1 be equipped with an adjustment mechanism with a degree of freedom that allows the distance between the camera 2 and the paper 10 to be adjusted.

[0066] [Example of optimal distance display] It is desirable that the MFP 1 displays the optimum distance so that the distance between the camera 2 and the paper 10 is the optimum distance.

[0067] FIG. 11 is a diagram showing an example of a display by a display unit. For example, the MFP 1 displays a message as shown in the figure on a display device such as a panel. Note that the message may be displayed in a format other than that shown in the figure. For example, the message may be, "Please shift the camera angle slightly to the right," or "Please move the large-size document table a little more to the left," etc.

[0068] The optimum distance between the camera 2 and the paper 10 may differ depending on the lens of the camera 2, etc. Therefore, it is desirable for the MFP 1 to display the optimum distance to the user.

[0069] 1, the MFP 1 may calculate the difference between the optimum distance and the current distance and display the difference. Therefore, the MFP 1 includes a sensor that measures the distance between the camera 2 and the paper 10.

[0070] If such a display is possible, an instruction can be given to the user to optimize the distance between the camera 2 and the paper 10.

[0071] The display unit may be a device other than a panel. For example, the MFP 1 may display on another information processing device via a network.

[0072] [Example of functional configuration] 12 is a diagram showing an example of the functional configuration. Specifically, MFP1 includes a reading unit 1F1, an imaging unit 1F2, an adjustment unit 1F3, a storage unit 1F4, and an image processing unit 1F5. MFP1 also preferably includes a display unit 1F6.

[0073] The reading unit 1F1 performs a reading procedure for reading the first recording medium. For example, the reading unit 1F1 is realized by a scanner 4 or the like.

[0074] The photographing unit 1F2 performs a photographing procedure for photographing the second recording medium. For example, the photographing unit 1F2 is realized by a camera 2 or the like.

[0075] The adjustment unit 1F3 performs an adjustment procedure to move or rotate the camera 2 relative to the second recording medium. For example, the adjustment unit 1F3 is realized by an ADF or the like.

[0076] The storage unit 1F4 performs a storage procedure for storing the second image. For example, the storage unit 1F4 is realized by the storage device 5 or the like.

[0077] The image processing unit 1F5 performs an image processing procedure to correct the first image based on the second image and generate a third image. For example, the image processing unit 1F5 is realized by the CPU 3 or the like.

[0078] The display unit 1F6 performs a display procedure for displaying the optimum distance between the camera 2 and the paper 10. For example, the display unit 1F6 is realized by a display device or the like.

[0079] The reading unit 1F1 reads a first recording medium. Meanwhile, the photographing unit 1F2 photographs a second recording medium, which is larger than the first recording medium, to generate a first image. This first image is preferably free of distortion, like the second image. Therefore, the MFP1 corrects the first image by referencing the second image. By correcting in this way, the MFP1 can generate a third image with less distortion. Therefore, the MFP1 can improve the reading accuracy when reading large paper that does not fit on the platen.

[0080] Furthermore, if such correction is possible, it is possible to prevent the device for reading large-sized paper from becoming large in size, and also to suppress the increase in cost required to increase the accuracy of the camera 2.

[0081] In particular, to shorten the distance between camera 2 and paper 10 and to miniaturize the device, it is desirable for camera 2 to use a device with a wide-angle lens. However, when a wide-angle lens is used to take a photo, the edges of the image tend to become distorted. Therefore, if the above-described correction can be performed, MFP1 can reduce distortion caused by the wide-angle lens. Therefore, by employing camera 2 with a wide-angle lens, MFP1 can achieve high resolution and a compact device.

[0082] Furthermore, if the lens of the camera 2 is made inexpensive, the precision of the lens is likely to vary. However, even with such a lens, if the above-described correction can be performed, the MFP 1 can reduce distortion caused by the wide-angle lens. Therefore, the MFP 1 can suppress cost increases.

[0083] [Other embodiments] The overall process may be performed in an order other than that shown in FIG.

[0084] Fig. 13 is a diagram showing a modified example of the overall processing. Compared to Fig. 3, the overall processing shown in Fig. 13 differs in that the processing is performed in the following order: photographing the recording medium (step S0305), "pre-processing" (steps S0301 to S0304), and correction (step S0306). In other words, the "pre-processing" may be performed either before or after photographing the recording medium (step S0305).

[0085] The image reading device may be made up of two or more devices.

[0086] The recording medium may be, for example, other than paper (also referred to as "plain paper"). For example, the recording medium may be coated paper, label paper, an overhead projector sheet, film, a flexible thin plate, or the like. That is, the material of the recording medium may be any material to which toner or ink droplets can adhere, be temporarily adhered, adhere and fix, or adhere and penetrate. Specifically, the recording medium may be a recording medium such as paper, film, or cloth, an electronic circuit board, an electronic component such as a piezoelectric element (also referred to as a "piezoelectric member"), a powder layer (also referred to as a "powder layer"), an organ model, or a test cell. Thus, the material of the recording medium may be any material to which a liquid can adhere, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or a combination thereof.

[0087] Each device may be a plurality of devices. That is, each device may be configured to perform distributed, redundant, or parallel processing using a plurality of devices. On the other hand, each device may be integrated. That is, the plurality of devices described above may be realized by a single device.

[0088] The image reading method as described above may be realized by an image reading program. That is, the image reading program causes devices such as an arithmetic unit, a control unit, and a storage unit provided in a computer to cooperate with each other to realize the image reading method. The image reading program may also be distributed via a computer-readable recording medium or a telecommunications line.

[0089] The above-described embodiment shows a preferred example, but a person skilled in the art can realize various modifications from the disclosed content. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0090] 1: MFP 1F1: Reading unit 1F2: Photography Department 1F3: Adjustment section 1F4: Storage section 1F5: Image processing section 1F6: Display section 2: Camera 3: CPU 4: Scanner 5: Storage device 6: Interface 10: Paper 11: Large size document holder 100: Image reading system C1: Horizontal center line C2: Vertical center line [Prior art documents] [Patent documents]

[0091] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-180712

Claims

1. a reading unit that reads the first recording medium; an imaging unit that images a second recording medium having a size larger than the first recording medium; an adjustment unit that moves or rotates the imaging unit; a storage unit configured to store a second image showing a marker that serves as a reference for correcting a first image showing a result of the image capturing by the image capturing unit; an image processing unit that corrects the first image based on the second image to generate a third image; a display unit that displays an optimum distance between the photographing unit and the second recording medium; Equipped with The display unit As the optimum distance, a distance at which the second recording medium is photographed as large as possible within the range of the angle of view of the photographing unit is displayed. Image reading device.

2. The reading unit reading the first recording medium placed on a platen, The large size document holder has The marker is formed; The imaging unit is capturing an image of the marker formed on the large size document platen to generate a fourth image; capturing an image of the second recording medium placed on the large-size document table to generate the first image; The image processing unit comparing the second image with the fourth image to generate correction data; Correcting the distortion of the first image based on the correction data to generate the third image.

2. The image reading device according to claim 1.

3. The large size document table is The image reader is a separate object.

3. The image reading device according to claim 2.

4. The large size document table is The second recording medium is electrostatically attracted.

4. The image reading device according to claim 3.

5. An image reading system having a photographing device and an image reading device connected to the photographing device via a network, The imaging device is an imaging unit that images a second recording medium having a size larger than the first recording medium; An adjustment unit that moves or rotates the imaging unit, The image reading device a reading unit that reads the first recording medium; a storage unit configured to store a second image showing a marker that serves as a reference for correcting a first image showing a result of the image capturing by the image capturing unit; an image processing unit that corrects the first image based on the second image to generate a third image; a display unit that displays an optimum distance between the photographing unit and the second recording medium; Equipped with The display unit As the optimum distance, a distance at which the second recording medium is photographed as large as possible within the range of the angle of view of the photographing unit is displayed. Image reading system.

Images