Image reading device

Abstract

Conventional image forming machines could not extract individual images from an image containing images of multiple documents scanned using clear files. Therefore, in conventional image scanning machines, in order to extract individual images from an image containing images of multiple documents, it was necessary to arrange the multiple documents one by one on the document glass without using clear files. [Solution] In the second multi-crop mode, the process of determining the edges of the original document is performed on the image contained in the area corresponding to the clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line). As a result, it is possible to cut out each original document image from an image containing images of multiple original documents scanned using a clear file.

Description

Technical Field

[0001] The present invention relates to an image reading device that cuts out an image of each document from an image including a plurality of documents.

Background Art

[0002] Conventionally, in an image reading device, an image of a plurality of documents placed on a document table glass is read, an edge of each document is detected from an image including the images of the plurality of documents, and an image of each document is cut out based on the edge (Patent Document 1). FIG. 18 is a diagram showing a read image when images of three documents placed on a document table glass are read. FIG. 18(a) shows an image after the processing of Patent Document 1 is performed on the read image. By performing the processing of Patent Document 1, as shown in FIG. 18(b), the images of each document are output in a cut-out state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, it has become common to digitize forms such as receipts. For example, it is conceivable to read a plurality of receipts placed on a document table glass and digitize each receipt by performing the processing of Patent Document 1 on the plurality of receipts. Since a receipt is a document with an image formed on roll paper, it may be curved (curled), and it takes time to place a plurality of such curved documents on a document table glass. Also, it takes time to arrange a plurality of documents one by one on a document table glass.

[0005] Therefore, as shown in Figure 18(c), it is conceivable to place a clear file containing multiple receipts or other documents on the document glass and perform the scanning. However, when a clear file containing multiple receipts or other documents is scanned and the scanned image is processed according to Patent Document 1, the following problems arise. Specifically, as shown in Figure 18(d), the image is cut off based on the edges of the clear file, and the images of documents A, B, and C are output as a single image. In other words, conventional image forming apparatuses could not extract images of individual documents from an image containing images of multiple documents scanned using a clear file. Therefore, in conventional image reading apparatuses, in order to extract images of individual documents from an image containing images of multiple documents, it was necessary to arrange multiple documents one by one on the document glass without using a clear file.

[0006] In view of the above issues, the present invention aims to provide an image reading device that can easily extract images from each document from an image containing images of multiple documents. [Means for solving the problem]

[0007] To solve the above problems, the image reading device according to the present invention is: The manuscript tray on which the manuscript is placed and A reading unit that scans the document placed on the document tray from below the document tray to read the image. Control unit for controlling the reading unit and The determination means for determining the size of the aforementioned manuscript and Equipped with The reading unit reads the image included in the readable area that the reading unit can read. The control unit performs edge detection processing to detect edges from the image read by the reading unit, and detection processing to detect the area of ​​the document from the detected edge image. The edge detection process is characterized in that it is performed only in the area inside the size of the original document. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image reading device that can easily extract images from each document from an image containing images of multiple documents. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram showing the configuration of an image forming apparatus. [Figure 2] This is a perspective view showing the configuration of the document scanning device. [Figure 3] This is a perspective view showing the configuration of the reading device. [Figure 4] This is a block diagram showing an example of a control configuration for an image forming apparatus. [Figure 5] This diagram illustrates a configuration in which the angle of the pressure plate relative to the reading device is detected by an opening / closing detection sensor. [Figure 6] This is a flowchart explaining how to determine the size of a document placed on the document glass. [Figure 7] This is a flowchart explaining the process of detecting the size of a document. [Figure 8] This is a diagram illustrating the method for detecting the size of a document. [Figure 9] This diagram illustrates the process of detecting image edges. [Figure 10] This diagram illustrates the process of detecting candidate edges in a document. [Figure 11] This diagram illustrates the process of determining the edges of a document. [Figure 12] This is a flowchart explaining the standard multi-crop mode. [Figure 13] This figure illustrates the region where the process for determining the edges of the original document is performed in the first embodiment. [Figure 14] This is a flowchart illustrating the multi-crop mode for filing documents in the first embodiment. [Figure 15] This figure shows the screen for setting the size in the multi-crop mode for filing documents. [Figure 16]This is a diagram showing the state where the clear file is abutted against the first abutting portion and the second abutting portion and placed on the original document glass. [Figure 17] This is a diagram for explaining the process of determining the edge of the original document in the fourth embodiment. [Figure 18] This is a diagram for explaining the clipping of an image according to the conventional technique.

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the shapes of the components described in this embodiment and their relative arrangements, etc. should be appropriately changed according to the configuration of the apparatus to which this invention is applied and various conditions, and the scope of this invention is not intended to be limited to the following embodiments.

[0011] 〔First Embodiment〕 [Image Forming Apparatus] FIG. 1 is a cross-sectional view showing the configuration of a color electrophotographic copying machine (hereinafter referred to as an image forming apparatus) 100 used in this embodiment. Note that the image forming apparatus is not limited to a copying machine, and may be, for example, a facsimile apparatus, a printing machine, a printer, or the like. Further, the recording method is not limited to the electrophotographic method, and may be, for example, an inkjet method or the like. Furthermore, the form of the image forming apparatus may be either a monochrome or a color form.

[0012] Hereinafter, the configuration and functions of the image forming apparatus 100 will be described with reference to FIG. 1. As shown in FIG. 1, the image forming apparatus 100 includes an original document reading apparatus 200 including an original document feeding apparatus 201 and a reading apparatus 202, and an image printing apparatus 301.

[0013] [Original Document Reading Apparatus] The documents P loaded in the document loading section 2 of the document feeding device 201 are fed one by one by the pickup roller 3, and then transported further downstream by the feed roller 4. Opposite the feed roller 4, a separation roller 5 is provided that presses against the feed roller 4. The separation roller 5 is configured to rotate when a load torque exceeding a predetermined torque is applied to it, and has the function of separating documents that have been fed in a stacked state.

[0014] The pickup roller 3 and the feed roller 4 are connected by a swing arm 12. The swing arm 12 is supported on the rotation axis of the feed roller 4 so that it can rotate around the rotation axis of the feed roller 4.

[0015] The original document P is transported by the feed roller 4, etc., and discharged into the output tray 10 by the output roller 11.

[0016] The scanner 202 is equipped with a scanning unit 16 that reads the image of the first side of the document being transported. The scanning unit 16 has an LED 110, an image sensor 111, and an optical component group 112. The image sensor 111 has multiple light-receiving elements that receive R (red), G (green), and B (blue) light across the main scanning direction (corresponding to the width direction perpendicular to the transport direction in which the document is transported). The scanning unit 16 reads the image of the surface (first side) of the document as follows: Specifically, the LED 110, as a light source, irradiates (emits) light onto the surface of the document via the scanning glass 108. The optical component group 112 guides the reflected light from the document received via the scanning glass 108 to the image sensor 111. The image sensor 111 outputs analog image data based on the received light. The image sensor 111 simultaneously reads one line of image across the main scanning direction. Therefore, by reading one line of image multiple times with the image sensor 111 while transporting the document, the image sensor 111 can output image data that includes the entire document.

[0017] Furthermore, the document feeding device 201 is equipped with a reading unit 17 that reads the image of the second side of the document being transported. The configuration of the reading unit 17 is the same as that of the reading unit 16, so its description will be omitted.

[0018] As described above, the manuscript is read aloud.

[0019] There are two methods for reading documents: the flow-reading method and the pressure-plate reading method. The flow-reading method reads the image of a document being transported in the manner described above. The pressure-plate reading method reads the image of a document placed on the document glass 214 of the reading device 202 by a reading unit 16 that moves at a constant speed in the sub-scanning direction (to the right in Figure 1) corresponding to the transport direction in which the document is transported. Typically, images of sheet documents are read using the flow-reading method, while images of bound documents such as books and booklets are read using the pressure-plate reading method.

[0020] Figure 2 is a perspective view showing the configuration of the document scanning device 200. Note that the document feeding device 201 is omitted in Figure 2.

[0021] The document feeder 201 is rotatable relative to the scanner 202 between an open position in which the document glass 214 is exposed and a closed position in which the document glass 214 is covered by the pressure plate 18. The document feeder 201 has a pressure plate 18 that presses the document placed on the document glass 214 toward the document glass 214 when in the closed position.

[0022] Figure 3 is a cross-sectional view showing the configuration of the scanning device 202. The scanning device 202 includes a scanning glass 108, a document glass 214, a scanning unit 16, a scanning guide 215, a motor 219 that moves the scanning unit 16 in a sub-scanning direction perpendicular to the main scanning direction, a document size detection sensor 216, and an open / close detection sensor 217.

[0023] In the pressure plate reading method, the document placed on the document glass 214 is read by the reading unit 16, which moves in the sub-scanning direction (from left to right in Figure 3) by the motor 219. The reading unit 16 is guided in the sub-scanning direction by the reading guide 215.

[0024] The size of a document placed on the document glass 214 is determined based on the reading result of the reading unit 16 and the detection result of the document size detection sensor 216. Specifically, the length of the document placed on the document glass 214 in the main scanning direction is determined based on the reading result of the reading unit 16, and the length of the document placed on the document glass 214 in the main scanning direction is determined based on the document size detection sensor 216. The document size detection sensor 216 can be any known sensor, for example, that includes a light-emitting unit and a light-receiving unit.

[0025] <Image Printing Device> The image printing apparatus 301 is equipped with a sheet storage tray 18 for storing recording media. The recording media is any material on which an image is formed by the image forming apparatus, and includes, for example, paper, resin sheets, cloth, OHP sheets, labels, etc.

[0026] The recording media stored in the sheet storage tray 18 are fed out by the pickup roller 19 and then sent to the registration roller 20 by the transport rollers 39, 40, 41, 42, etc.

[0027] The image printing device 301 is also provided with a manual feed tray 44 for loading recording media. Recording media loaded in the manual feed tray 44 are fed out by a pickup roller 43 and then transported to the registration roller 20 by a transport roller 42 or the like.

[0028] The leading edge of the recording medium being transported by the pre-registration roller 37 abuts against the registration roller 20. As a result, a loop is formed in the recording medium between the registration roller 20 and the pre-registration roller 37, correcting (reducing) the skew of the recording medium.

[0029] The image signal output from the document reader 200 is input to optical scanning devices 21Y, 21M, 21C, and 21K, which include a semiconductor laser and polygon mirrors, for each color component. Specifically, the image signal for yellow output from the document reader 200 is input to optical scanning device 3Y, and the image signal for magenta output from the document reader 200 is input to optical scanning device 3M. Similarly, the image signal for cyan output from the document reader 200 is input to optical scanning device 3C, and the image signal for black output from the document reader 200 is input to optical scanning device 3K. While the following description focuses on the configuration for forming the yellow image, the configurations for magenta, cyan, and black are similar.

[0030] The outer surface of the photosensitive drum 22Y is charged by the charger 23Y. After the outer surface of the photosensitive drum 22Y is charged, laser light corresponding to the image signal input from the document reader 200 to the optical scanning device 21Y is irradiated onto the outer surface of the photosensitive drum 22Y from the optical scanning device 21Y via an optical system such as a polygon mirror and mirrors. As a result, an electrostatic latent image is formed on the outer surface of the photosensitive drum 22Y.

[0031] Next, the electrostatic latent image is developed by the toner in the developing unit 24Y, and a toner image is formed on the outer surface of the photosensitive drum 22Y. The toner image formed on the photosensitive drum 22Y is transferred to the transfer belt 27, which acts as an intermediate transfer body, by the transfer roller 25Y, which is located opposite the photosensitive drum 22Y. Any toner remaining on the outer surface of the photosensitive drum 22Y after the toner image has been transferred to the transfer belt 27 is collected by the cleaning unit 26Y.

[0032] The yellow, magenta, cyan, and black toner images transferred to the transfer belt 27 are transferred to the recording medium by the transfer roller pair 28. A high voltage is applied to the transfer roller pair 28, and this high voltage causes the toner images to be transferred to the recording medium. In conjunction with this transfer timing, the registration roller 20 feeds the recording medium to the transfer roller pair 28.

[0033] As described above, the recording medium onto which the toner image has been transferred is fed to the fuser 29, which acts as the fixing unit, and is heated and pressurized by the fuser 29 to fix the toner image onto the recording medium. In this way, an image is formed on the recording medium by the image forming apparatus 100.

[0034] When image formation is performed in single-sided printing mode, the recording medium that has passed through the fuser 29 is discharged to the output tray 31 by the output roller 30. When image formation is performed in double-sided printing mode, after the first surface of the recording medium is fixed by the fuser 29, the recording medium is transported to the inversion path 32 by the inversion roller 38. The recording medium transported to the inversion path 32 is inverted by the inversion roller 38, with the first and second surfaces reversed, and then transported to a transport guide equipped with transport rollers 33, 34, 35, and 36. The recording medium is then transported again to the registration roller 20 by the transport rollers 33, 34, 35, and 36, and an image is formed on the second surface of the recording medium in the manner described above. After that, the recording medium is discharged to the output tray 31 by the output roller 30.

[0035] The above is a description of the configuration and functions of the image forming apparatus 100.

[0036] <Control Configuration> {Control configuration for image printing device} Figure 4 is a block diagram showing an example of the control configuration of the image forming apparatus 100. First, the control configuration of the image printing apparatus 301 will be described.

[0037] As shown in Figure 2, the system controller 151 includes a CPU 151a, a ROM 151b, and a RAM 151c. The system controller 151 is also connected to an analog-to-digital (A / D) converter 153, a high-voltage control unit 155, a motor control device 600, sensors 159, and an AC driver 160. The system controller 151 is capable of sending and receiving data and commands to and from each of the connected units.

[0038] The CPU 151a executes various sequences related to a predetermined image formation sequence by reading and executing various programs stored in the ROM 151b.

[0039] RAM151c is a memory device. RAM151c stores various data, such as setting values ​​for the high-voltage control unit 155 and command values ​​for the motor control device 600.

[0040] The system controller 151 receives signals from the sensors 159 and sets the set value of the high-voltage control unit 155 based on the received signals.

[0041] The high-voltage control unit 155 supplies the necessary voltage to the high-voltage unit 156 (charger 310, developer 314, transfer charger 315, etc.) according to the setting value set by the system controller 151.

[0042] The motor control device 600 controls the motor 509 that drives the load provided on the image printing device 301 in accordance with the command output from the CPU 151a.

[0043] The A / D converter 153 receives a detection signal from the thermistor 154, which detects the temperature of the fuser heater 161, converts the detection signal from an analog signal to a digital signal, and transmits it to the system controller 151. The system controller 151 controls the AC driver 160 based on the digital signal received from the A / D converter 153. The AC driver 160 controls the fuser heater 161 so that its temperature reaches the temperature required for the fixing process. The fuser heater 161 is a heater used for the fixing process and is included in the fuser unit 318.

[0044] As described above, the system controller 151 controls the operation sequence of the image forming apparatus 100.

[0045] {Control configuration of document reading device} Next, the control configuration of the document reader 200 will be described. The CPU 401 controls the document reader 200 by executing a program stored in the non-volatile memory 402.

[0046] The operation unit 403 provides a user interface. The CPU 401 controls the operation unit 403 to display an operation screen on the display unit provided on the operation unit 403, which allows the user to set the type of recording medium to be used (hereinafter referred to as paper type). The CPU 401 receives the information set by the user from the operation unit 403 and outputs the information set by the user to the system controller 151. The system controller 151 transmits information indicating the status of the image forming apparatus to the operation unit 403. This information includes, for example, the number of images to be formed, the progress of the image forming operation, and information regarding sheet jams or double feedings in the image printer 301 and the document feeder 201. The operation unit 403 displays the information received from the system controller 151 on the display unit.

[0047] The image data output by the reading units 16 and 17 is input to the image processing unit 404. The image processing unit 404 converts the analog image data into digital image data. The higher the intensity of the reflected light, the higher the numerical value of the digital image data. This numerical level will be referred to as the luminance value below. The image processing unit 404 performs known corrections such as shading correction on the image data.

[0048] The detection result from the open / close detection sensor 217 is input to the CPU 401. Figure 5 illustrates the configuration in which the angle of the pressure plate 18 relative to the reading device 202 is detected by the open / close detection sensor 217. Figure 5(a) is a perspective view showing the configuration of the reading device. Figure 5(b) illustrates the configuration of the open / close detection sensor 217. Figure 5(c) shows the relationship between the output of the open / close detection sensor 217 and the angle of the pressure plate 18 relative to the reading device 202.

[0049] As shown in Figure 5(a), the reading device 202 is provided with an open / close detection sensor 217 that detects the angle of the pressure plate 18 relative to the reading device 202. As shown in Figure 5(b), the open / close detection sensor 217 comprises a photosensor 218, 219 and a flag 220, each consisting of a light-emitting unit that emits light and a light-receiving unit that receives light. The flag 220 is in the state shown in Figure 5(b-1), where the pressure plate 18 (document feeder 201) is in the open position and protrudes from the upper surface of the reading device 202. In the state shown in Figure 5(b-1), a 'H (high level)' signal is output from the photosensors 218 and 219 to the CPU 401.

[0050] When the pressure plate 18 is closed by the user, the flag 220 is pressed downward by the pressure plate 18. As a result, the flag 220 is positioned between the light-emitting and light-receiving parts of the photosensor 218, and the signal input from the photosensor 218 to the CPU 401 becomes 'L (low level)'. When the pressure plate 18 is closed further by the user, the flag 220 is pressed downward by the pressure plate 18. As a result, the flag 220 is positioned between the light-emitting and light-receiving parts of the photosensor 219, and the signal input from the photosensor 219 to the CPU 401 becomes 'L (low level)'.

[0051] The CPU 401 makes the determination shown in Figure 5(c) based on the signals input from the photosensors 218 and 219. Specifically, if the signal input from the photosensor 218 is 'L' (OFF) and the signal input from the photosensor 219 is 'L' (OFF), the CPU 401 determines that the angle θ of the pressure plate 18 relative to the reading device 202 is greater than 25°. Also, if the signal input from the photosensor 218 is 'H' (ON) and the signal input from the photosensor 219 is 'L' (OFF), the CPU 401 determines that the angle θ of the pressure plate 18 relative to the reading device 202 is greater than 5° and less than or equal to 25°. Furthermore, the CPU 401 determines that the angle θ of the pressure plate 18 relative to the reading device 202 is between 0° and 5° if the signal input from the photosensor 218 is 'H' (ON) and the signal input from the photosensor 219 is 'H' (ON). In the following, an angle θ greater than 25° is referred to as the "open" state, an angle θ greater than 5° and 25° or less is referred to as the "partially closed" state, and an angle θ between 0° and 5° is referred to as the "closed" state.

[0052] The detection result from the document size detection sensor 216 is input to the CPU 401. When the pressure plate reading method is used, the CPU 401 determines the size of the document based on the detection result from the document size detection sensor 216 and the reading result from the reading unit 16.

[0053] Figure 6 is a flowchart illustrating the method for determining the size of a document placed on the document glass 214. The processing in this flowchart is executed by the CPU 401. Note that the size detection detects sizes defined by JIS standards, etc. (standard sizes).

[0054] In S101, when it is detected that the pressure plate 18 is in the "open" state, the CPU 401 controls the motor 219 in S102 to move the reading unit 16 to the detection position. As a result, the reading unit 16 is positioned below the document glass 214. The detection position is, for example, a position 50 mm toward the document size detection sensor 216 from the first abutment part 220 shown in Figure 5(a). The first abutment part 220 is the part against which one end of the document in the sub-scanning direction is pressed when the user places the document on the document glass 214. The reading device 202 is also provided with a second abutment part 221 against which one end of the document in the main scanning direction is pressed when the user places the document on the document glass 214. The document placed on the document glass 214 is positioned by abutting against the first abutment part 220 and the second abutment part 221. In standby mode, the reading unit 16 is positioned, for example, between the document glass 214 and the reading glass 108 in the sub-scanning direction.

[0055] Next, in S103, the CPU 401 acquires the detection result S0 from the document size detection sensor 216 and stores it in a memory (not shown).

[0056] In S104, if it is detected that the pressure plate 18 is in the "closed" state, in S105, the CPU 401 turns on the LED 110 provided on the reading unit 16.

[0057] Subsequently, in S106, the process of detecting the size of the document is performed. The process of detecting the size of the document will be described later.

[0058] Next, in S107, the CPU 401 turns off the LED 110 provided on the reading unit 16, and in S108, the CPU 401 controls the motor 219 to move the reading unit 16 to the standby position.

[0059] Figure 7 is a flowchart illustrating the process of S106 (document size detection process) in the flowchart shown in Figure 6. This process is executed by CPU 401.

[0060] In S201, the CPU 401 acquires the detection result S1 from the document size detection sensor 216 and stores it in a memory (not shown).

[0061] Subsequently, in S202, the CPU 401 controls the motor 219 to move the reading unit 16 from the detection position to the standby position. While the reading unit 16 is moving from the detection position to the standby position, it reads (scans) the document placed on the document glass 214.

[0062] Next, in S203, the CPU 401 calculates (determines) the length of the document placed on the document glass 214 in the main scanning direction based on the image obtained by the reading unit 16 in S202. Specifically, for example, the CPU 401 determines the position of the end of the document placed on the document glass 214 that is opposite to the end that is in contact with the second abutment portion 221, based on the image obtained by the reading unit 16 in S202. Then, the CPU 401 determines the length in the main scanning direction between the determined end position and the second abutment portion 221 as the length of the document placed on the document glass 214 in the main scanning direction.

[0063] Then, in S204, CPU401 determines the size of the document.

[0064] Figure 8 illustrates the method for detecting the size of a document. When a document is present on the document size detection sensor 216 in the sub-scanning direction, S1 is the same value as S0. On the other hand, when there is no document on the document size detection sensor 216 in the sub-scanning direction, S1 is a different value from S0. This is due to the following reasons. Specifically, when the pressure plate 18 is in the "open" state when there is no document on the document size detection sensor 216 in the sub-scanning direction, the light emitted from the light-emitting part of the document size detection sensor 216 does not enter the light-receiving part. On the other hand, when the pressure plate 18 is in the "closed" state when there is no document on the document size detection sensor 216 in the sub-scanning direction, the light emitted from the light-emitting part of the document size detection sensor 216 is reflected by the pressure plate 18 and enters the light-receiving part. For these reasons, when there is no document on the document size detection sensor 216 in the sub-scanning direction, S1 is a different value from S0.

[0065] The CPU 401 determines the length of the document in the sub-scanning direction to be "large" if S0 and S1 are the same value, and determines the length of the document in the sub-scanning direction to be "small" if S0 and S1 are different values. Based on this determination result and the length in the main scanning direction determined in S202 based on the image obtained by the reading unit 16, the CPU 401 determines the size of the document according to the table shown in Figure 8.

[0066] [Reading mode] Next, the reading modes provided by the reading device 202 in this embodiment will be described. In this embodiment, the reading device 202 provides a normal scan mode, a first multi-crop mode, and a second multi-crop mode in the pressure plate reading method. The reading mode can be set, for example, by the user using the operation unit 403.

[0067] <Normal scan mode> When the normal scan mode is set and a command to start scanning a document is received, the CPU 401 controls the motor 219 to move the scanning unit 16 in the sub-scanning direction. Specifically, the CPU 401 moves the scanning unit 16 by a length in the sub-scanning direction corresponding to the size determined by the size detection process. As the scanning unit 16 moves in the sub-scanning direction, it reads the image of the document placed on the document glass 214.

[0068] The CPU 401 generates an image file based on the reading results from the reading unit 16 and outputs it to an external device (such as a smartphone, PC, or tablet) of the image forming apparatus 100. The image size of the image file is determined by the size detection process.

[0069] <First Multi-Crop Mode> Next, the first multi-crop mode will be explained. The first multi-crop mode is a mode in which multiple documents placed on the document glass 214 are scanned simultaneously, the image of each document is extracted from the scanned images, and each document image is generated as an image file.

[0070] {Image edge detection} In the first multi-crop mode, the CPU 401 detects candidate edges for each image contained in the read image. For the process of detecting image edges, known methods using differential filters such as the Canny method are used.

[0071] Figure 9 illustrates the process of detecting image edges. Figure 9 shows scanned images when three documents are placed on the document glass 214. Figure 9(a) shows an image obtained by scanning documents 1, 2, and 3 placed on the document glass 214 simultaneously. Figure 9(b) shows the image from Figure 9(a) after the edge detection process has been applied. As shown in Figure 9(b), the edge detection process detects not only the edges of the documents but also the edges of the content within the documents.

[0072] {Process for detecting candidate edges in the original document} Next, CPU 401 performs known image processing on the detected edge image, such as edge tracking, which tracks the connections between edge pixels to detect independent regions, or Hough transform, which detects line candidates from the edge image.

[0073] Figure 10 illustrates the process of detecting candidate edges of a document. Figure 10(a) shows the edges of document D detected by the edge tracking method, as well as the edges of content X, Y, and Z of document D. Figure 10(b) shows the image after applying the Hough transform to the detected edges. Direction x corresponds to the main scanning direction, and direction y corresponds to the sub-scanning direction. In the process of detecting candidate edges of a document, the contour of a rectangular region with edges formed by four straight lines is determined as a candidate edge of the document. For example, in Figure 10(b), the edge of content Y and the edge of document D are determined as candidate edges of the document. Through these processes, candidate edges of the document are determined, as shown in Figure 9(c).

[0074] {Process to determine the edges of the original document} Figure 11 illustrates the process of determining the edges of the document. Figure 11(a) shows candidates a, b, c, and d as candidates for the document edges. The following describes the processing of candidate a by CPU 401, which performs the following processing for each candidate.

[0075] As shown in Figure 11(b), the CPU 401 calculates the length (width) W in the x-direction and the length L in the y-direction of candidate a. The CPU 401 determines that candidate a is not the outline of the document if at least one of the following conditions is met: the width W is less than a predetermined width W0, and the length L is less than a predetermined length L0.

[0076] On the other hand, if the CPU 401 does not satisfy both conditions that the width W is less than a predetermined width W0 and the length L is less than a predetermined length L0, it performs the following processing. Specifically, the CPU 401 determines whether candidate a is inside the region enclosed by the other candidates b, c, and d. More specifically, the CPU 401 determines, for example, whether the four vertices of candidate a are inside the region enclosed by the other candidates b, c, and d (i.e., whether the region enclosed by candidate a overlaps with at least the region enclosed by candidate b, the region enclosed by c, and the region enclosed by d). For example, if the scanned image is an image like the one shown in Figure 11(c), the four vertices of candidate a are not inside the region enclosed by the other candidates b, c, and d, so the CPU 401 determines that candidate a is an edge of the document. On the other hand, if the scanned image is as shown in Figure 11(d), the vertex of candidate a is inside the region enclosed by the other candidates d, so candidate a is not determined to be an edge of the document. With this processing, in the image shown in Figure 9(c), edge candidate 4 is not determined to be an edge of the document, and edge candidates 1, 2, and 3 are determined to be edges of the document.

[0077] Figure 12 is a flowchart illustrating the first multi-crop mode in this embodiment. The processing in this flowchart is executed by the CPU 401. The processing in this flowchart starts when an instruction to start scanning a document is input while the first multi-crop mode is set.

[0078] In S301, the CPU 401 moves the reading unit 16 to scan the readable area that can be read by the reading unit 16. The reading unit 16 reads images of multiple documents placed on the document glass 214 while moving in the sub-scanning direction. The area of ​​the readable area is, for example, greater than or equal to the largest standard size document (e.g., A3 size) that fits on the document glass 214. Furthermore, the area of ​​the readable area is less than or equal to the area of ​​the mounting surface (the surface on which the document is placed) of the document glass 214. Figure 2 shows, as an example, the readable area 250 and an A3-sized document P positioned on the document glass 214, abutting against the first abutment part 220 and the second abutment part 221.

[0079] Next, in S302, the CPU 401 generates an image file (see Figure 9(a)) containing images of multiple documents placed on the document glass 214, based on the reading results of the reading unit 16.

[0080] Subsequently, in S303, CPU401 performs a process to detect image edges from the image file generated in S302.

[0081] Then, in S304, the CPU 401 performs a process to determine (detect) candidate edges of the document. The CPU 401 stores the detected candidate document regions in memory (not shown).

[0082] Next, in S305, if there are no candidate edges for the document, CPU401 terminates processing this flowchart.

[0083] On the other hand, if there are candidate edges for the document in S305, the CPU 401 performs a process to determine the edges of the document in S306.

[0084] In S307, the CPU 401 crops the image based on the edges of the original document determined in S306. Furthermore, the CPU 401 rotates the cropped image to generate an image file, which is then output to an external device (such as a smartphone, PC, or tablet) of the image forming apparatus 100. The image for each original document is generated as a separate image file, as shown in Figure 9(d). The CPU 401 may also crop the image after rotating it.

[0085] <Second Multi-Crop Mode> Next, the second multi-crop mode will be described. In this embodiment, by applying the following configuration as the second multi-crop mode, an image reading device is provided that can easily extract images of each document from an image containing images of multiple documents. The following describes the case in which a clear file of a predetermined size containing multiple documents is used. In this embodiment, the predetermined size is described as corresponding to A4 size, but for example, the predetermined size may be corresponding to B5 size or legal size. The multiple documents may include, for example, receipts, forms, Post-it notes, etc.

[0086] Figure 13 is a diagram illustrating the region where the edge of the document is determined. Figure 13 shows the image read by the reading unit 16 when a clear file containing documents 1, 2, and 3 is placed on the document glass 214 with the first and second abutment sections 220 and 221 pressing against it.

[0087] In the second multi-crop mode of this embodiment, the process of determining the edges of the original document is performed on the image contained in the area corresponding to the clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line). The area corresponding to the clear file corresponds to the area where the clear file is located when the clear file is positioned by the first abutment part 220 and the second abutment part 221 and placed on the document glass 214. Furthermore, the area corresponding to the clear file corresponds to the area that does not include the edge of the positioned clear file along the main scanning direction that is opposite to the edge that is in contact with the first abutment part 220. Furthermore, the area corresponding to the clear file corresponds to the area that does not include the edge of the positioned clear file along the sub-scanning direction that is opposite to the edge that is in contact with the second abutment part 221. That is, the area corresponding to the clear file is shorter than the length of the clear file by a predetermined margin d in the main scanning direction, and shorter than the length of the clear file by a predetermined margin d in the sub-scanning direction.

[0088] Figure 14 is a flowchart illustrating the second multi-crop mode in this embodiment. The processing in this flowchart is executed by the CPU 401. The processing in this flowchart starts when an instruction to start scanning a document is input while the second multi-crop mode is set.

[0089] The process from S401 to S402 is the same as the process from S301 to S302 in Figure 12, so the explanation is omitted.

[0090] Next, in S403, the CPU401 determines the region where edge detection processing will be performed, as explained in Figure 13.

[0091] The processes from S403 to S408 are the same as those from S302 to S307 in Figure 12, so their explanation will be omitted.

[0092] As described above, in the second multi-crop mode of this embodiment, the process of determining the edges of the original document is performed on the image contained in the area corresponding to the clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line). As a result, it is possible to prevent the images of multiple original documents from being output as a single image due to the image being cut off based on the edges of the clear file. Consequently, it is possible to extract each original document's image from an image containing images of multiple original documents read using a clear file. In other words, it is possible to provide an image reading device that can easily extract each original document's image from an image containing images of multiple original documents.

[0093] Furthermore, when the second multi-crop mode is selected by the operation unit 403, the user may be notified to place the clear file against the first and second abutment sections 220 and 221 and then onto the document glass 214.

[0094] The area corresponding to the clear file may also correspond to the area of ​​the positioned clear file that does not include the edge in contact with the first abutment portion 220 and the edge on the opposite side of that edge, along the main scanning direction. Alternatively, the area corresponding to the clear file may also correspond to the area of ​​the positioned clear file that does not include the edge in contact with the second abutment portion 221 and the edge on the opposite side of that edge, along the sub-scanning direction.

[0095] In this embodiment, in the second multi-crop mode, image edge detection, document edge candidate detection, and document edge determination are performed after the detection area is determined, but this is not limited to this. For example, the area for determining the document edge may be determined after image edge detection has been performed. That is, image edge detection is performed on an image in which the entire readable area has been read. As a result, the edge of the clear file is detected as an image edge. Furthermore, the detection of candidate document edges and the determination of document edges may be performed on the image contained in the area corresponding to the clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line).

[0096] Furthermore, for example, the area for determining the document edge may be determined after image edge detection and document edge candidate detection have been performed. That is, image edge detection and document edge candidate detection are performed on the image in which the entire readable area has been read. As a result, the edge of the clear file is detected as a document edge candidate. Then, the document edge may be determined for the image contained in the area corresponding to the clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line).

[0097] [Second Embodiment] The parts of the image forming apparatus 100 that are the same as those in the first embodiment will not be described.

[0098] <Second Multi-Crop Mode> The second multi-crop mode in this embodiment will be described below. In this embodiment, when the user selects the second multi-crop mode, a screen for setting the size of the clear file is displayed on the operation unit 403.

[0099] Figure 15 shows the screen for setting the size in the second multi-crop mode. The user can select the size of the clear file based on the screen shown in Figure 15. While Figure 15 displays "A4 clear file" and "B5 clear file" as options, other size options, such as "legal size clear file," may also be available. The following explanation will describe the case where "A4 clear file" is selected.

[0100] The CPU 401 determines the area for edge detection processing based on the size set by the user using the screen shown in Figure 15. Specifically, as described in the first embodiment, the process of determining the edges of the original document is performed on the image contained in the area corresponding to an A4 clear file (the area other than the shaded area in Figure 13, i.e., the area enclosed by the dashed line).

[0101] As described above, in this embodiment, when the user selects the second multi-crop mode, a screen for setting the size of the clear file is displayed on the operation unit 403. The CPU 401 then determines the area for edge detection processing based on the size set by the user on the screen shown in Figure 15. As a result, processing is performed to determine the edges of the original document for the image contained in the area corresponding to the clear file. As a result, it is possible to prevent the image of multiple original documents from being output as a single image due to the image being cut off based on the edges of the clear file. Furthermore, it is possible to extract each original document's image from an image containing images of multiple original documents read using a clear file. In other words, it is possible to provide an image reading device that can easily extract each original document's image from an image containing images of multiple original documents.

[0102] In addition, the area in which edge detection processing is performed may be determined based on the size determined by the method described in Figure 6 in the first embodiment.

[0103] [Third Embodiment] The parts of the image forming apparatus 100 that are the same as those in the first embodiment will not be described.

[0104] <Second Multi-Crop Mode> The second multi-crop mode in this embodiment will be described below. The following description will focus on the case where a clear file of a predetermined size containing multiple documents is used. In this embodiment, the predetermined size will be described as corresponding to A4 size, but for example, the predetermined size may also be corresponding to B5 size or legal size.

[0105] Figure 16 shows the clear file placed on the document glass 214 with the first abutment portion 220 and the second abutment portion 221 in contact with each other. In this embodiment, the CPU 401 controls the reading unit 16 and the motor 219 to read only the area enclosed by the dashed line in Figure 15.

[0106] Specifically, the CPU 401 controls the reading unit 16 and motor 219 so that in the sub-scanning direction, it reads only the area corresponding to the clear file. More specifically, for example, the CPU 401 moves the reading unit 16 from the first abutment unit 220 to the right in Figure 16. Then, the CPU 401 stops the reading unit 16 at a position to the left of the edge of the positioned clear file along the main scanning direction that is opposite to the edge in contact with the first abutment unit 220 (stopping position). That is, the CPU 401 controls the reading unit 16 so that in the sub-scanning direction, it reads the image in the section from the edge of the clear file in contact with the first abutment unit 220 to the stopping position. Furthermore, the CPU 401 controls the reading unit 16 so that in the main scanning direction, it reads only the area corresponding to the clear file. Specifically, the CPU 401 controls the reading unit 16 so that in the main scanning direction, it reads an area shorter than the clear file. In other words, in this embodiment, the reading area read by the reading unit 16 is shorter than the length of the clear file by a predetermined margin d in the main scanning direction, and shorter than the length of the clear file by a predetermined margin d in the sub-scanning direction.

[0107] CPU401 performs the process of determining the edges of the original document for the scanned image.

[0108] As described above, in this embodiment, the CPU 401 controls the reading unit 16 and the motor 219 to read only the area corresponding to the clear file. Then, a process is performed to determine the edges of the original document for the read image. As a result, the process of determining the edges of the original document is performed for the image contained in the area corresponding to the clear file. Consequently, it is possible to prevent the image of multiple original documents from being output as a single image due to the image being cut off based on the edges of the clear file. Furthermore, it is possible to extract each original document's image from an image containing images of multiple original documents read using a clear file. In other words, it is possible to provide an image reading device that can easily extract each original document's image from an image containing images of multiple original documents.

[0109] Furthermore, the travel distance of the reading unit 16 in this embodiment is shorter than the travel distance of the reading unit 16 when reading the entire readable area of ​​the reading unit 16. As a result, the reading time in the filing document multi-crop mode can be shortened compared to the reading time in the normal multi-crop mode. In other words, the productivity of the image reading device can be improved.

[0110] In this embodiment, the CPU 401 controls the reading unit 16 to read only the area corresponding to the clear file in the main scanning direction, but this is not limited to this. For example, the CPU 401 may control the reading unit 16 to read the area corresponding to the length of the image sensor 111 in the main scanning direction.

[0111] Furthermore, if the user selects the second multi-crop mode, a screen for setting the size of the clear file, as shown in Figure 15, may be displayed on the operation unit 403. The CPU 401 may control the reading area of ​​the reading unit 16 in the manner described above, based on the size set by the user on the screen shown in Figure 15.

[0112] [Fourth Embodiment] The parts of the image forming apparatus 100 that are the same as those in the first embodiment will not be described.

[0113] Second multi-crop mode > The second multi-crop mode in this embodiment will be described below. In this embodiment, as in the second embodiment, when the user selects the second multi-crop mode, a screen for setting the size of the clear file shown in Figure 15 will be displayed on the operation unit 403. The following description will focus on the case when "A4 clear file" is selected.

[0114] Figure 17 illustrates the process of determining the edges of a document. In this embodiment, the readable area is read by the reading unit 16. Figure 17 shows an image of the readable area read by the reading unit 16 when a clear file containing documents 1, 2, and 3 is placed on the document glass 214 with the first and second abutment parts 220 and 221 touching it. Figure 17 shows a state where document 3 extends beyond the clear file.

[0115] In the second multi-crop mode of this embodiment, image edge detection is performed on the image included in the readable area. As a result, as shown in Figure 17(a), the edges of each document, the edges of the images included in each document, and the edges of the clear file are detected.

[0116] Subsequently, CPU401 masks the image corresponding to the edges of the clear file corresponding to the size set by the user. Specifically, CPU401 deletes (makes the pixels white) the image corresponding to the edges of the clear file corresponding to the size set by the user. As a result, an image like the one shown in Figure 17(b) is generated. In other words, the edges of document 3 are cut off.

[0117] Therefore, CPU 401 interpolates the edges of document 3 using a known method such as morphological transformation. As a result, the image shown in Figure 17(c) is generated. In this result, only the edges of the clear file are removed.

[0118] Subsequently, the CPU 401 performs the detection of candidate document edges and the determination of document edges as described in the first embodiment for the image shown in Figure 17(c).

[0119] With the above configuration, even if the manuscript is sticking out of the clear file, it can be properly cut out.

[0120] Furthermore, the configurations of the first to fourth embodiments can also be applied to a sheet of paper (backing) on ​​which multiple documents are attached. [Explanation of Symbols]

[0121] 16 Reading Unit 403 Operation section 214 Document glass 216 Document size detection sensor 401 CPU

Claims

1. The manuscript tray on which the manuscript is placed and A reading unit that scans the document placed on the document tray from below the document tray to read the image. Control unit for controlling the reading unit and The determination means for determining the size of the aforementioned manuscript and Equipped with The reading unit reads the image included in the readable area that the reading unit can read. The control unit performs edge detection processing to detect edges from the image read by the reading unit, and detection processing to detect the area of ​​the document from the detected edge image. An image reading device characterized in that, in the edge detection process, the edge detection process is performed only in the area inside the size of the original document.

2. The image reading device has an operating section into which the user inputs information regarding the size. The image reading device according to claim 1, characterized in that the determination means determines the size of the original document based on the information regarding the size.

Images