Image reading apparatus comprising a processor configured to extract an edge in an area corresponding to a holding member as an edge of an image corresponding to the document

An image reading apparatus includes a transparent member having a placement surface on which a document is to be placed, a reading unit configured to read an image of the document placed on the transparent member via the transparent member, and a reading mode in which an image of a document, placed in a holding member with a transparent portion, is read. The document to be read is placed in the holding member so as to be visible via the transparent portion and the holding member is placed on the placement surface with the transparent portion of the holding member in contact with the placement surface. A processor detects an edge in an image acquired by the reading unit in the reading mode, and to extract an image surrounded by an edge detected in an area surrounded by an edge corresponding to the holding member in the reading mode.

BACKGROUND

Field of the Disclosure

The present disclosure relates to an image reading apparatus that cuts out images of a plurality of documents from an image including the plurality of documents.

Description of the Related Art

Some typically known image reading apparatuses perform processing of reading images of a plurality of documents placed on a document positioning glass plate, detecting edges of the plurality documents from an image including the images of the plurality of documents, and cutting out the images of the plurality of documents based on the edges (Japanese Patent Application Laid-Open No. 2002-10059).FIG.18Ais a diagram illustrating a read image in a case where images of three documents placed on a document positioning glass plate have been read.FIG.18Billustrates images having been subjected to the processing discussed in Japanese Patent Application Laid-Open No. 2002-10059 on the read image. Performing of the processing discussed in Japanese Patent Application Laid-Open No. 2002-10059 outputs images of documents in a state where each image is cut out as illustrated inFIG.18B.

In recent years, there has been increased opportunities to digitize sales slips, such as receipts. For example, a plurality of receipts is digitized by reading the plurality of receipts placed on a document positioning glass plate and performing the processing discussed in Japanese Patent Application Laid-Open No. 2002-10059. A receipt is likely to be curved (curled) because it is a document made of a roll of paper on which an image is formed. Thus, it takes time and effort to place a plurality of curved documents on a document positioning glass plate. Placing the plurality of documents on the document positioning glass plate one by one also requires time and effort.

Thus, as illustrated inFIG.18C, placing a transparent document folder that holds a plurality of documents, such as receipts, on the document positioning glass plate and reading the documents in the transparent document folder may be considered. However, the following issue arises when the transparent document folder holding the plurality of documents, such as receipts, is used to read the documents and the processing discussed in Japanese Patent Application Laid-Open No. 2002-10059 is performed on the read image. Specifically, as illustrated inFIG.18D, an image is cut out based on the edge of the transparent document folder, so that images of documents A, B, and C are output as a single image. In other words, typical image reading apparatuses cannot cut out individual images of documents from an image including the images of the documents read by using the transparent document folder. Thus, with the typical image reading apparatuses, a plurality of documents is to be placed on the document positioning glass plate one by one without using the transparent document folder in order to cut out the individual images of the documents from an image including the images of the document.

SUMMARY

In consideration of the above-described issue, the present disclosure generally relates to an image reading apparatus capable of easily cutting out individual images of documents from an image that includes the images of the documents.

According to an aspect of the present disclosure, an image reading apparatus includes a transparent member having a placement surface on which a document is to be placed, a reading unit configured to read an image of the document placed on the transparent member via the transparent member; and at least one processor configured to detect an edge in an image acquired by the reading unit in a reading mode, and extract an image surrounded by an edge, detected in an area surrounded by an edge corresponding to a holding member, in the reading mode. The holding member has a transparent portion and the document to be read is placed in the holding member so as to be visible via the transparent portion, and the holding member is placed on the placement surface with the transparent portion of the holding member in contact with the placement surface.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments according to the present disclosure will be described with reference to the accompanying drawings. Shapes and relative positions of constituent elements described in the exemplary embodiments should be changed as appropriate depending on a configuration and various conditions of an apparatus to which the present disclosure is applied, and the scope of the present disclosure is not limited to the below-described exemplary embodiments.

A first exemplary embodiment of the present disclosure will be described below.FIG.1is a sectional diagram illustrating a configuration of an electrophotographic color copying machine (hereinafter, referred to as image forming apparatus)100employed in the present exemplary embodiment. The image forming apparatus100is not limited to a copying machine, and may be a facsimile apparatus, a printing apparatus, or a printer. A recording method is not limited to the electrophotographic recording method, and may be an ink jet recording method. Further, the image forming apparatus100may form an image in either a monochromatic format or a color format.

Hereinafter, a configuration and a function of the image forming apparatus100will be described with reference toFIG.1. As illustrated inFIG.1, the image forming apparatus100includes a document reading apparatus200including a document feeding apparatus201and a reading apparatus202and an image printing apparatus301.

Documents P stacked on a document stacking portion2of the document feeding apparatus201are fed by a pick-up roller3one by one, and further conveyed downstream by a feeding roller4. A separation roller5in pressure contact with the feeding roller4is disposed at a position facing the feeding roller4. The separation roller5rotates when a load torque greater than or equal to a predetermined torque is applied thereto, and has a function of separating two documents fed in an overlapping state.

The pick-up roller3and the feeding roller4are coupled to each other with a swinging arm12. The swinging arm12is supported by a rotating shaft of the feeding roller4to be rotatable about the rotating shaft.

Each of the documents P is conveyed by the feeding roller4and discharged to a discharge tray10by discharge rollers11.

A reading unit16for reading an image of a first face of a conveyed document is disposed on the reading apparatus202. The reading unit16includes a light-emitting diode (LED)110, an image sensor111, and a group of optical components112. The image sensor111includes a plurality of light receiving elements for receiving light of red (R), green (G), and blue (B), disposed in a main scanning direction, which is a direction corresponding to a width direction orthogonal to a conveyance direction in which the document is conveyed. The reading unit16reads an image of a surface (first surface) of a document as follows. The LED110serving as a light source emits light to irradiate the surface of the document with light via a reading glass108. The group of optical components112receives light reflected on the document via the reading glass108, and guides the light to the image sensor111. The image sensor111outputs analog image data based on the received light. The image sensor111simultaneously reads an image corresponding to one line in the main scanning direction. Thus, the image sensor111can output image data including data of the entire document by reading an image corresponding to one line for a plurality of times while the document is being conveyed.

A reading unit17for reading an image of a second face of the conveyed document is disposed on the document feeding apparatus201. A configuration of the reading unit17is similar to that of the reading unit16, so that descriptions thereof are omitted.

A document is read thereby as described above.

Reading methods of documents include a document-feeding-reading method and a pressing plate reading method. In the document-feeding-reading method, an image of a conveyed document is read through the above-described method. In the pressing plate reading method, an image of a document placed on a document positioning glass plate214of the reading apparatus202is read by the reading unit16which is moved at a certain speed in the sub-scanning direction (i.e., a rightward direction inFIG.1) corresponding to the conveyance direction in which the document is conveyed. Typically, images of documents in sheet form are read with the document-feeding-reading method, and images of bound documents, such as a book and a booklet, are read with the pressing plate reading method.

FIG.2is a perspective diagram illustrating a configuration of the document reading apparatus200. InFIG.2, illustration of the document feeding apparatus201is omitted.

The document feeding apparatus201is pivotable with respect to the reading apparatus202between the opening position at which the document positioning glass plate214is exposed and the closed position at which the document positioning glass plate214is covered by the pressing plate18. The document feeding apparatus201includes the pressing plate18configured to press the document placed on the document positioning glass plate214toward the document positioning glass plate214at the closed position.

FIG.3is a sectional diagram illustrating a configuration of the reading apparatus202. The reading apparatus202includes a reading glass108, a document positioning glass plate214, a reading unit16, a reading guide215, a motor222for moving the reading unit16in the sub-scanning direction orthogonal to the main scanning direction, a document size detection sensor216, and an opening-closing detection sensor217.

The motor222moves the reading unit16in the sub-scanning direction (from the left to right inFIG.3) and the reading unit16reads a document placed on the document positioning glass plate214with the pressing plate reading method. The reading unit16is guided by the reading guide215to be moved in the sub-scanning direction.

A size of the document placed on the document positioning glass plate214is determined based on a reading result obtained by the reading unit16and a detection result obtained by the document size detection sensor216. More specifically, a length in the main scanning direction of the document placed on the document positioning glass plate214is determined based on the reading result obtained by the reading unit16, and a length in the sub-scanning direction of the document placed on the document positioning glass plate214is determined based on the detection result obtained by the document size detection sensor216. For example, a known sensor including a light emitting portion and a light receiving portion may be used as the document size detection sensor216.

A sheet storage tray14for storing a recording medium is disposed inside the image printing apparatus301. The recording medium is a material on which an image is to be formed by the image forming apparatus100. Examples of the recording medium include a sheet of paper, a resin sheet, a fabric, an overhead projector (OHP) sheet, and a label.

A recording medium stored in the sheet storage tray14is fed by a pick-up roller19, and conveyed to registration rollers20by, for example, conveyance rollers39,40,41, and42.

The image printing apparatus301further includes a manual sheet feeding tray44for stacking recording media. A recording medium stacked on the manual sheet feeding tray44is fed by pick-up rollers43and conveyed to the registration rollers20by, for example, the conveyance rollers42.

A leading end of a recording medium conveyed by pre-registration rollers37comes into contact with the registration rollers20. As a result, a loop is formed on the recording medium at a position between the registration rollers20and the pre-registration rollers37, so that skew of the recording medium is corrected (reduced).

Image signals output from the document reading apparatus200are individually input, by color component basis, to optical scanning devices21Y,21M,21C, and21K including semiconductor lasers and polygon mirrors. More specifically, an image signal relating to a yellow color component output from the document reading apparatus200is input to the optical scanning device21Y, and an image signal relating to a magenta color component output from the document reading apparatus200is input to the optical scanning device21M. An image signal relating to a cyan color component output from the document reading apparatus200is input to the optical scanning device21C, and an image signal relating to a black color component output from the document reading apparatus200is input to the optical scanning device21K. Hereinafter, constituent elements for forming a yellow image will be described, and the constituent elements for forming magenta, cyan, and black images are similar to those for yellow.

An outer circumferential surface of a photosensitive drum22Y is charged by a charging device23Y. After the outer circumferential surface of the photosensitive drum22Y is charged, laser light in accordance with the image signal input to the optical scanning device21Y from the document reading apparatus200is emitted to the outer circumferential surface of the photosensitive drum22Y from the optical scanning device21Y via the optical members, such as the polygon mirror and the mirror. Thus, an electrostatic latent image is formed on the outer circumferential surface of the photosensitive drum22Y.

Subsequently, a development device24Y serving as a development unit develops the electrostatic latent image with toner, so that a toner image is formed on the outer circumferential surface of the photosensitive drum22Y. The toner image formed on the photosensitive drum22Y is transferred to a transfer belt27serving as an intermediate transfer member by a transfer roller25Y disposed at a position facing the photosensitive drum22Y. Toner remaining on the outer circumferential surface of the photosensitive drum22Y after the toner image is transferred to the transfer belt27is collected by a cleaning unit26Y.

The toner images of yellow, magenta, cyan, and black transferred to the transfer belt27are transferred to a recording medium by a transfer roller pair28. High voltage that is applied to the transfer roller pair28causes the toner images to be transferred to the recording medium. The registration rollers20convey the recording medium to the transfer roller pair28in synchronization with this transfer timing.

The recording medium on which a toner image is transferred as described above is conveyed to a fixing device29serving as a fixing unit, so that the fixing device29applies heat and pressure to the recording medium to fix the toner image onto the recording medium. Thus, the image forming apparatus100forms an image on the recording medium.

In a case where image formation is performed in a one-sided printing mode, the recording medium having passed through the fixing device29is discharged to a discharge tray31by discharge rollers30. In a case where image formation is performed in a two-sided printing mode, the fixing device29performs the fixing processing on the first surface of the recording medium, and the recording medium is then conveyed to a reversing path32by reversing rollers38. The first surface and the second surface of the recording medium conveyed to the reversing path32are reversed by the reversing rollers38. The recording medium is then conveyed to a conveyance guide where conveyance rollers33,34,35, and36are disposed. The recording medium is conveyed to the registration rollers20again by the conveyance rollers33,34,35, and36, and an image is formed on the second surface of the recording medium with the above-described method. Thereafter, the recording medium is discharged to the discharge tray31by the discharge rollers30.

The configuration and the functions of the image forming apparatus100are described as the above.

[Control Configuration of Image Printing Apparatus]

FIG.4is a block diagram illustrating an example of a control configuration of the image forming apparatus100. Initially, a control configuration of the image printing apparatus301will be described.

As illustrated inFIG.4, a system controller151includes a central processing unit (CPU)151a, a read only memory (ROM)151b, and a random access memory (RAM)151c. The system controller151is connected to an analog to digital (A/D) conversion unit153, a high voltage control unit155, a motor control device600, sensors159, and an alternate current (AC) driver160. The system controller151can communicate data and commands with the respective units connected thereto.

The CPU151areads and performs various programs stored in the ROM151bto perform various sequences relating to a predetermined image forming sequence.

The RAM151cserves as a storage device. For example, various types of data such as a setting value for the high voltage control unit155and an instruction value for the motor control device600are stored in the RAM151c.

The system controller151receives signals from the sensors159, and sets a setting value for the high voltage control unit155based on the received signals.

According to the setting value set by the system controller151, the high voltage control unit155supplies necessary voltage to high voltage units156(e.g., a charging device23Y, a development device24Y, and a transfer charging device).

According to an instruction output from the CPU151a, the motor control device600controls a motor509for driving a load, disposed on the image printing apparatus301.

The A/D conversion unit153receives a detection signal output by a thermistor154for detecting a temperature of a fixing heater161, converts the detection signal to a digital signal from an analog signal, and transmits the digital signal to the system controller151. The system controller151controls the AC driver160based on the digital signal received from the A/D conversion unit153. The AC driver160controls the fixing heater161to set a temperature of the fixing heater161to a temperature sufficient for performing fixing processing. The fixing heater161is included in the fixing device29, and used for performing fixing processing.

The system controller151controls the operation sequence of the image forming apparatus100as described above.

[Control Configuration of Document Reading Apparatus]

Next, a control configuration of the document reading apparatus200will be described. A CPU401performs a program stored in a non-volatile memory402to control the document reading apparatus200.

An operation unit403provides a user interface. The CPU401controls the operation unit403to display an operation screen on a display unit on the operation unit403. In the operation screen, a user makes settings of, for example, a type of recording media (hereinafter, referred to as sheet type) to be used. The CPU401receives information about settings made by the user from the operation unit403and outputs the information about the settings made by the user to the system controller151. The system controller151transmits information indicating a state of the image forming apparatus100to the operation unit403. Examples of the information indicating a state of the image forming apparatus100includes information about the number of sheets on which images are to be formed, information about a progress status of image forming processing, and information about jamming of sheets or erroneous conveyance of sheets overlapping each other occurring in the image printing apparatus301or the document feeding apparatus201. The operation unit403displays the information received from the system controller151on the display unit.

Image data output from each of the reading units16and17is input to an image processing unit404. The image processing unit404converts analog image data to digital image data. The digital image data has a higher value with greater intensity of reflected light. Hereinafter, a level of this value is expressed as a luminance value. The image processing unit404performs correction such as known shading correction on the image data.

A detection result obtained by the opening-closing detection sensor217is input to the CPU401.FIGS.5A to5Care diagrams illustrating a configuration for detecting an angle of the pressing plate18with respect to the reading apparatus202with the opening-closing detection sensor217.FIG.5Ais a perspective diagram illustrating a configuration of the reading apparatus202.FIG.5Bis a diagram illustrating a configuration of the opening-closing detection sensor217.FIG.5Cis a table illustrating a relationship between the output of the opening-closing detection sensor217and the angle of the pressing plate18with respect to the reading apparatus202.

As illustrated inFIG.5A, the opening-closing detection sensor217for detecting the angle of the pressing plate18with respect to the reading apparatus202is disposed on the reading apparatus202. As illustrated inFIG.5B, the opening-closing detection sensor217includes photosensors218and219and a flag220. Each of the photosensors218and219includes a light emitting portion for emitting light and a light receiving portion for receiving light. As illustrated inFIG.5B-1, the flag220protrudes from the upper surface of the reading apparatus202when the pressing plate18(document feeding apparatus201) is at an opening position. In a state illustrated inFIG.5B-1, a high-level (H) signal is input to the CPU401from each of the photosensors218and219.

When the user closes the pressing plate18partway, the pressing plate18presses the flag220downward. As a result, the flag220is positioned between the light emitting portion and the light receiving portion of the photosensor218, and a level of the signal input to the CPU401from the photosensor218becomes low (L). When the user further closes the pressing plate18, the pressing plate18further presses the flag220downward. As a result, the flag220is positioned between the light emitting portion and the light receiving portion of the photosensor219, and a level of the signal input to the CPU401from the photosensor219becomes low (L).

The CPU401makes determination illustrated inFIG.5Cbased on the signals received from the photosensors218and219. More specifically, in a case where both of the signals received from the photosensors218and219are “L (OFF)”, the CPU401determines that an angle θ of the pressing plate18with respect to the reading apparatus202is greater than 25°. In a case where the signal received from the photosensor218is “H (ON)” and the signal received from the photosensor219is “L (OFF)”, the CPU401determines that the angle θ of the pressing plate18with respect to the reading apparatus202is greater than 5° and less than or equal to 25°.

In a case where both of the signals received from the photosensors218and219are “H (ON)”, the CPU401determines that the angle θ of the pressing plate18with respect to the reading apparatus202is greater than or equal to 0° and less than or equal to 5°. Hereinafter, a state where the angle θ is greater than 25° is called “opening state”, a state where the angle θ is greater than 5° and less than or equal to 25° is called “partly closed state”, and a state where the angle θ is greater than or equal to 0° and less than or equal to 5° is called “closed state”.

A detection result obtained by the document size detection sensor216is input to the CPU401. In a case where the pressing plate reading method is performed, the CPU401determines the size of the document based on a detection result obtained by the document size detection sensor216and a reading result obtained by the reading unit16.

FIG.6is a flowchart illustrating a method for determining the size of a document placed on the document positioning glass plate214. The processing illustrated in this flowchart is performed by the CPU401. A size (fixed size) specified by the Japanese Industrial Standards (JIS) is detected through the size detection.

In step S101, in response to the opening state of the pressing plate18being detected (YES in step S101), the processing proceeds to step S102. In step S102, the CPU401controls the motor222to move the reading unit16to a detection position. Thus, the reading unit16is moved to the lower side of the document positioning glass plate214. Examples of the detection position include a position shifted toward the document size detection sensor216by 50 mm from the first abutting portion223indicated inFIG.5A. The first abutting portion223refers to a portion on which one end of a document in the sub-scanning direction abuts when the user places the document on the document positioning glass plate214. The reading apparatus202also has a second abutting portion221on which another end of the document in a main scanning direction abuts when the user places the document on the document positioning glass plate214. The user positions the document to be placed on the document positioning glass plate214by making the document abut on the first abutting portion223and the second abutting portion221. Here, in a stand-by state, the reading unit16is located between the document positioning glass plate214and the reading glass108in the sub-scanning direction, for example.

Next, in step S103, the CPU401acquires a detection result from the document size detection sensor216and stores the detection result in a memory (not illustrated).

In step S104, in response to a closed state of the pressing plate18being detected (YES in step S104), the processing proceeds to step S105. In step S105, the CPU401turns on the LED110disposed on the reading unit16.

Thereafter, in step S106, the CPU401performs document size detection processing. The document size detection processing will be described below.

In step S107, the CPU401turns off the LED110disposed on the reading unit16. Then in step S108, the CPU401controls the motor222to move the reading unit16to a stand-by position.

FIG.7is a flowchart illustrating the processing performed in step S106(document size detection processing) of the flowchart inFIG.6. The processing illustrated in this flowchart is performed by the CPU401.

In step S201, the CPU401acquires a detection result51obtained by the document size detection sensor216and stores the detection result51in a memory (not illustrated).

Thereafter, in step S202, the CPU401controls the motor222to move the reading unit16from the detection position to the stand-by position. The reading unit16reads (scans) a document placed on the document positioning glass plate214while being moved from the detection position to the stand-by position.

In step S203, based on the image acquired by the reading unit16in step S202, the CPU401calculates (determines) a length of the document in the main scanning direction placed on the document positioning glass plate214. More specifically, the CPU401determines, for example, a position of one end opposite to another end abutting on the second abutting portion221from among the ends of the document placed on the document positioning glass plate214, based on the image acquired by the reading unit16in step S202. The CPU401determines a length from the determined position of the one end to the second abutting portion221in the main scanning direction to be a length of the document in the main scanning direction placed on the document positioning glass plate214.

In step S204, the CPU401determines the size of the document.

FIG.8is a table illustrating a method for detecting a document size. In a case where a document is present above the document size detection sensor216in the sub-scanning direction, values of the detection results S1 and S0 are the same. On the other hand, in a case where the document is not present above the document size detection sensor216in the sub-scanning direction, values of the detection results S1 and S0 are different. This situation occurs because of the following reasons. When the pressing plate18is open without the document above the document size detection sensor216in the sub-scanning direction, light emitted from the light emitting portion of the document size detection sensor216is not incident on the light receiving portion. On the other hand, when the pressing plate18is closed with the document above the document size detection sensor216in the sub-scanning direction, light emitted from the light emitting portion of the document size detection sensor216is reflected on the pressing plate18and incident on the light receiving portion. Thus, in a case where the document is not present above the document size detection sensor216in the sub-scanning direction, values of the detection results S1 and S0 are different.

The CPU401determines a length of the document in the sub-scanning direction as “Large” in a case where values of the detection results S0 and S1 are the same, and determines a length of the document in the sub-scanning direction as “Small” in a case where values of the detection results S0 and S1 are different. The CPU401determines, based on this determination result and the length in the main scanning direction determined based on the image acquired by the reading unit16in step S202, the size of the document according to the table inFIG.8.

Reading modes of the reading apparatus202according to the present exemplary embodiment will now be described. The reading apparatus202according to the present exemplary embodiment includes a normal scanning mode, a first multi-cropping mode, and a second multi-cropping mode as the reading modes of the pressing plate reading method. For example, the user can set a reading mode using the operation unit403.

In response to the user inputting an instruction to start reading of a document with the normal scanning mode set, the CPU401controls the motor222to move the reading unit16in the sub-scanning direction. More specifically, the CPU401moves the reading unit16by a length, in the sub-scanning direction, corresponding to the size determined through the size detection processing. The reading unit16reads an image of a document placed on the document positioning glass plate214while moving in the sub-scanning direction.

The CPU401generates an image file based on a reading result obtained by the reading unit16, and outputs the image file to an apparatus external to the image forming apparatus100(such an external apparatus includes a smartphone, a PC, and a tablet apparatus). The image size of the image file is the size determined through the size detection processing.

The first multi-cropping mode is now described. In the first multi-cropping mode, the reading apparatus202collectively reads a plurality of documents placed on the document positioning glass plate214, extracts images of the documents from a read image, and generates an image file for the respective images of the documents.

In the first multi-cropping mode, the CPU401detects candidates for an edge of each image included in a read image. In the processing for detecting an edge of each image, for example, a known method using a differential filter, such as the Canny method, is used.

FIGS.9A to9Dare diagrams illustrating the processing for detecting an edge of the respective images.FIG.9Aillustrates a read image of three documents placed on the document positioning glass plate214. The read image inFIG.9Ais acquired when the documents1,2, and3placed on the document positioning glass plate214are read collectively.FIG.9Bis a diagram illustrating an image which is acquired when edge detection processing is performed on the image illustrated inFIG.9A. As illustrated inFIG.9B, performing the edge detection processing detects also edges of objects in the documents1,2, and3in addition to the edges of the documents1,2, and3.

[Processing for Detecting Candidate for Edge of Document]

Next, the CPU401performs, on the images of the detected edges, image processing employing a known method such as an edge tracking method for detecting an independent area by tracking a connection between edge pixels or Hough transformation method for detecting a candidate for a straight line from an edge image.

FIGS.10A and10Bare diagrams illustrating the processing for detecting a candidate for an edge of a document.FIG.10Aillustrates an edge of a document D and edges of objects X, Y, and Z included in the document D detected with the edge tracking method.FIG.10Billustrates an image which is acquired when the Hough transformation is performed on the detected edges. The X direction corresponds to the main scanning direction, and the Y direction corresponds to the sub-scanning direction. In the processing for detecting a candidate for an edge of a document, the contour of a square area having an edge formed by four straight lines is determined to be a candidate for the edge of the document. For example, inFIG.10B, the edge of the object Y and the edge of the document D are determined to be edge candidates for the document. Through these processes, edge candidates1to4for the documents1to3as illustrated inFIG.9Care determined.

[Processing for Determining Edge of Document]

FIGS.11A to11Dare diagrams illustrating processing for determining the edge of a document.FIG.11Aillustrates candidates a, b, c, and d as candidates for edges of documents. Hereinafter, although the processing that the CPU401performs on the candidate a will be described, the CPU401performs the below-described processing on each of the candidates.

As illustrated inFIG.11B, the CPU401calculates a length (width) W in the X direction and a length L in the Y direction of the candidate a. In a case where the candidate a satisfies at least any one of conditions that the width W is less than a predetermined width W0 and that the length L is less than a predetermined length L0, the CPU401determines that the candidate a is not the contour of a document.

In contrast to this, in a case where the candidate a does not satisfy both of the conditions that the width W is less than the predetermined width W0 and that the length L is less than the predetermined length L0, the CPU401performs the following processing. The CPU401determines whether the candidate a is present within an area surrounded by any of the candidates b, c, and d. More specifically, for example, the CPU401determines whether four vertexes of the candidate a is present within an area surrounded by any of the candidates b, c, and d (i.e., whether the area surrounded by the candidate a overlaps with at least any one of the areas surrounded by the other candidates b, c, and d). For example, in a case where the read image is an image illustrated inFIG.11C, the CPU401determines that the candidate a is the edge of the document because none of the four vertexes of the candidate a is present within the area surrounded by any one of the other candidates b, c, and d.

In contrast to this, in a case the read image is such an image as illustrated inFIG.11D, the candidate a cannot be determined to be the edge of the document because one of the vertexes of the candidate a is present within the area surrounded by the candidate d. Through this processing, in the image illustrated inFIG.9C, the edge candidate4is not determined to be the edge of the document, and edge candidates1,2, and3are determined to be the edges of the documents.

FIG.12is a flowchart illustrating the first multi-cropping mode according to the present exemplary embodiment. The processing illustrated in this flowchart is performed by the CPU401. The processing illustrated in the flowchart is started in response to the CPU401receiving an instruction to start reading of a document in a state where the first multi-cropping mode is selected.

In step S301, the CPU401moves the reading unit16to scan a readable area that is readable by the reading unit16. The reading unit16reads images of a plurality of documents placed on the document positioning glass plate214while moving in the sub-scanning direction. For example, the size of the readable area is greater than or equal to a maximum size (e.g., A3-size) among a fixed-size document which can be placed on and fit into the document positioning glass plate214. Further, the size of the readable area is smaller than or equal to the size of the placement surface (i.e., a surface on which a document is placed) of the document positioning glass plate214. As an example,FIG.2illustrates a readable area250and an A3-size document P that is positioned by being made to abut on the first abutting portion223and the second abutting portion221on the document positioning glass plate214.

Next in step S302, the CPU401generates an image file (seeFIG.9A) including images of a plurality of documents placed on the document positioning glass plate214, based on the reading result obtained by the reading unit16.

In step S303, the CPU401then performs the processing for detecting edges of the images from the image of the image file generated in step S302.

In step S304, the CPU401then performs the processing for determining (detecting) candidates for the edges of the documents. The CPU401stores the detected candidates for the edges of the documents in a memory (not illustrated).

In step S305, if no candidates for the edges of the documents is detected (NO in step S305), the CPU401ends the processing of this flowchart.

In step S305, if a candidate for the edges of the documents is present (YES in step S305), the processing proceeds to step S306. In step S306, the CPU401performs the processing for determining the edges of the documents.

In step S307, the CPU401cuts out images based on the edges of the documents determined in step S306. Further, the CPU401rotates the cut-out images, generates image files, and outputs the image files to the apparatus external to the image forming apparatus100(such an external apparatus includes a smartphone, a PC, or a tablet apparatus). The images of the documents are generated as separate image files as illustrated inFIG.9D. The CPU401may cut out the images after rotating the images.

Next, the second multi-cropping mode will be described. In the present exemplary embodiment, by applying the following configuration as the second multi-cropping mode, an image reading apparatus capable of easily cutting out images of documents from an image including the images of the documents is provided. Hereinafter, the second multi-cropping mode will be described using a case where a transparent document folder of a predetermined size that holds a plurality of documents is used. While the predetermined size described in the present exemplary embodiment corresponds to an A4-size, the predetermined size may be a size corresponding to a B5-size or a legal-size. Examples of the plurality of documents include a receipt, a sales slip, and a sticky note.

FIG.13is a diagram illustrating an area on which the processing for determining an edge of a document is to be performed.FIG.13illustrates an image read by the reading unit16in a state where a transparent document folder holding documents1,2, and3is placed on the document positioning glass plate214with the transparent document folder abutting on the first abutting portion223and the second abutting portion221.

In the second multi-cropping mode according to the present exemplary embodiment, processing for determining an edge of a document is performed on an image included in an area corresponding to the transparent document folder (i.e., the area surrounded by a dashed line, which excludes the shaded area inFIG.13). The area corresponding to the transparent document folder corresponds to, for example, an area where the transparent document folder is present when the transparent document folder is positioned with the aid of the first abutting portion223and the second abutting portion221and is placed on the document positioning glass plate214. Further, the area corresponding to the transparent document folder corresponds to an area that excludes one edge opposite to another edge abutting on the first abutting portion223from among the edges in the main scanning direction of the transparent document folder having been positioned. Furthermore, the area corresponding to the transparent document folder corresponds to an area that excludes one edge opposite to another edge abutting on the second abutting portion221from among the edges in the sub-scanning direction of the transparent document folder having been positioned. In other words, the area corresponding to the transparent document folder has a length shorter than a length of the transparent document folder by a predetermined margin d in the main scanning direction and a length shorter than a length of the transparent document folder by a predetermined margin d in the sub-scanning direction.

FIG.14is a flowchart illustrating the second multi-cropping mode according to the present exemplary embodiment. The processing illustrated in this flowchart is performed by the CPU401. The processing of this flowchart is started in response to the CPU401receiving an instruction to start reading of a document with the second multi-cropping mode set.

The operations in steps S401and S402are similar to those in steps S301and S302inFIG.12, so that descriptions thereof are omitted.

In step S403, the CPU401determines an area on which the edge detection processing is to be performed, as illustrated inFIG.13.

The operations in steps S404to S408are similar to those in steps S303to S307inFIG.12, so that descriptions thereof are omitted.

As described above, in the second multi-cropping mode according to the present exemplary embodiment, the processing for determining an edge of a document is performed on the image included in the area corresponding to the transparent document folder (i.e., the area surrounded by a dashed line, which excludes the shaded area inFIG.13). This makes it possible to prevent images of a plurality of documents from being output as a single image, which is caused by an image being cut out based on the edge of the transparent document folder. Thus, individual images of a plurality of documents can be cut out from the image that includes the plurality of images of the documents read by using the transparent document folder. In other words, it is possible to provide an image reading apparatus capable of easily cutting out individual images of documents from an image including the images of the documents.

The operation unit403may issue a notification that prompts the user to place the transparent document folder on the document positioning glass plate214and make the transparent document folder abut on the first abutting portion223and the second abutting portion221, in response to the second multi-cropping mode being selected via the operation unit403.

The area corresponding to the transparent document folder may correspond to an area excluding both of one edge abutting on the first abutting portion223and another edge opposite to the one edge from among the edges in the main scanning direction of the transparent document folder having been positioned. The area corresponding to the transparent document folder may also correspond to an area excluding both of one edge abutting on the second abutting portion221and another edge opposite to the one edge from among the edges in the sub-scanning direction of the transparent document folder having been positioned.

In the second multi-cropping mode according to the present exemplary embodiment, detection of an image edge, detection of a document edge candidate, and determination of a document edge are performed after a detection area is determined. The present exemplary embodiment is not limited thereto. For example, the area for determination of the document edge may be determined after detection of the image edge is performed. In other words, detection of the image edge is performed on a read image of the entire readable area250. Thus, an edge of the transparent document folder is detected as the image edge.

Detection of the document edge candidate and determination of the document edge may be performed on the image included in the area corresponding to the transparent document folder (i.e., the area surrounded by a dashed line, which excludes the shaded area inFIG.13).

For example, an area for determination of the document edge may be determined after detection of the image edge and detection of the document edge candidate are performed. In other words, detection of the image edge and detection of the document edge candidate are performed on a read image of the entire readable area250. Thus, an edge of the transparent document folder is detected as the document edge candidate. Determination of the document edge may be performed on the image included in the area corresponding to the transparent document folder (i.e., the area surrounded by a dashed line, which excludes the shaded area inFIG.13).

In the present exemplary embodiment, a description has been provided using a case where the transparent document folder is used. In another exemplary embodiment, any holding member that has a transparent portion and is capable of holding a document may be used. The transparent document folder is included in the holding member.

A second exemplary embodiment of the present disclosure will be described below. Descriptions of configurations of the image forming apparatus100similar to those described in the first exemplary embodiment will be omitted.

The second multi-cropping mode according to a second exemplary embodiment will be described. In the present exemplary embodiment, a screen for setting the size of the transparent document folder is displayed on the operation unit403in response to the second multi-cropping mode being selected by the user.

FIG.15is a diagram illustrating a screen for setting the size in the second multi-cropping mode.

The user can select the size of the transparent document folder based on the screen illustrated inFIG.15. While options, such as “A4-size Transparent Document Folder” and “B5-size Transparent Document Folder”, are displayed on the screen inFIG.15, other options of other sizes, such as “Legal-size Transparent Document Folder”, may also be displayed thereon. Hereinafter, a description will be provided of a case where “A4-size Transparent Document Folder” is selected.

The CPU401determines an area on which the edge detection processing is to be performed based on the size set by the user using the screen illustrated inFIG.15. More specifically, the processing for determining an edge of a document is performed on the image included in the area corresponding to the A4-size transparent document folder (i.e., the area surrounded by a dashed line, which excludes the shaded area inFIG.13), as described in the first exemplary embodiment.

As described above, according to the present exemplary embodiment, in response to the second multi-cropping mode being selected by the user, a screen for setting the size of the transparent document folder is displayed on the operation unit403. The CPU401then determines an area on which the edge detection processing is to be performed based on the size set by the user using the screen inFIG.15. Thus, the processing for determining the edge of the document is performed on the image included in the area corresponding to the transparent document folder. This makes is possible to prevent images of a plurality of documents from being output as a single image, which is caused by an image being cut out based on the edge of the transparent document folder. Further, the individual images of the plurality of documents can be cut out from the image that includes the images of the plurality of documents read by using the transparent document folder. In other words, it is possible to provide an image reading apparatus capable of easily cutting out individual images of documents from an image including the images of the documents.

The area on which the edge detection processing is to be performed may be determined based on the size determined through the method illustrated inFIG.6, described in conjunction with the first exemplary embodiment.

A third exemplary embodiment of the present disclosure will be described below. Descriptions of configurations of the image forming apparatus100similar to those described in the first exemplary embodiment will be omitted.

The second multi-cropping mode according to the present exemplary embodiment will be described. Hereinafter, a description will be provided of a case where a transparent document folder of a predetermined size that holds a plurality of documents is used. While the predetermined size described in the present exemplary embodiment corresponds to an A4-size, the predetermined size may be a B5-size, a legal-size, and the like.

FIG.16is a diagram illustrating a state where a transparent document folder is placed on the document positioning glass plate214with the transparent document folder abutting on the first abutting portion223and the second abutting portion221. In the present exemplary embodiment, the CPU401controls the reading unit16and the motor222to read only the area surrounded by a dashed line inFIG.16.

More specifically, the CPU401controls the reading unit16and the motor222to read only an area corresponding to the transparent document folder in the sub-scanning direction. Yet more specifically, for example, the CPU401moves the reading unit16rightward inFIG.16from the first abutting portion223. The CPU401stops the reading unit16at a position (stopping position) on the left side of one edge opposite to another edge abutting on the first abutting portion223, from among the edges in the main scanning direction of the transparent document folder having been positioned. In other words, the CPU401controls the reading unit16to read an image of a section ranging from an edge position of the transparent document folder abutting on the first abutting portion223to the stopping position. The CPU401controls the reading unit16to read only an area corresponding to the transparent document folder in the main scanning direction. More specifically, the CPU401controls the reading unit16to read an area having a length shorter than a length of the transparent document folder in the main scanning direction. In other words, in the present exemplary embodiment, a reading area read by the reading unit16has a length shorter than a length of the transparent document folder by a predetermined margin d in the main scanning direction and a length shorter than a length of the transparent document folder by a predetermined margin d in the sub-scanning direction.

The CPU401performs the processing for determining an edge of a document on the read image.

As described above, the CPU401controls the reading unit16and the motor222to read only the area corresponding to the transparent document folder in the present exemplary embodiment. The processing for determining an edge of a document is then performed on the read image. Thus, the processing for determining an edge of a document is performed on the image included in the area corresponding to the transparent document folder. This makes it possible to possible to prevent images of a plurality of documents from being output as a single image, which is caused by an image being cut out based on the edge of the transparent document folder. Further, the individual images of the plurality of documents can be cut out from the image that includes the images of the plurality of documents read by using the transparent document folder. In other words, it is possible to provide an image reading apparatus capable of easily cutting out individual images of documents from an image including the images of the documents

A moving distance of the reading unit16in the present exemplary embodiment is shorter than a moving distance thereof in reading the entire readable area250. Thus, readout time in the filed document multi-cropping mode (i.e., second multi-cropping mode) can be reduced to be shorter than readout time in the normal multi-cropping mode (i.e., first multi-cropping mode). Therefore, it is possible to improve the productivity of the image reading apparatus.

In the present exemplary embodiment, the CPU401controls the reading unit16to read only the area corresponding to the transparent document folder in the main scanning direction. However, the present exemplary embodiment is not limited thereto. For example, the CPU401may control the reading unit16to read an area corresponding to the length of the image sensor111.

In response to the second multi-cropping mode being selected by the user, the screen for the user to set the size of a transparent document folder illustrated inFIG.15may be displayed on the operation unit403. The CPU401may control the reading area of the reading unit16through the above-described method based on the size set by the user using the screen inFIG.15.

A fourth exemplary embodiment of the present disclosure will be described. Descriptions of the configurations of the image forming apparatus100similar to those described in the first exemplary embodiment will be omitted.

The second multi-cropping mode according to the present exemplary embodiment will be described. In the present exemplary embodiment, the screen for the user to set the size of a transparent document folder illustrated inFIG.15is displayed on the operation unit403when the second multi-cropping mode is selected by the user, as in the second exemplary embodiment. Hereinafter, a description will be provided of a case where “A4-size Transparent Document Folder” is selected.

FIGS.17A to17Care diagrams illustrating processing for determining an edge of a document. In the present exemplary embodiment, the readable area250is read by the reading unit16.FIG.17Aillustrates an image read by the reading unit16in a state where a transparent document folder holding documents1,2, and3is placed on the document positioning glass plate214with the transparent document folder abutting on the first abutting portion223and the second abutting portion221.FIG.17Aillustrates a state where the document3partly lies off the transparent document folder.

In the second multi-cropping mode according to the present exemplary embodiment, the processing for detecting an image edge is performed on an image included in the readable area250. Thus, edges of the documents1to3, edges of images included in the documents1to3, and an edge of the transparent document folder are detected as illustrated inFIG.17A.

Thereafter, the CPU401masks an image corresponding to the edge of the transparent document folder having a size corresponding to the size set by the user. More specifically, the CPU401deletes an image (i.e., whitens the pixels) corresponding to the edge of the transparent document folder of the size set by the user, for example.

As a result, an image illustrated inFIG.17Bis generated. Specifically, the edge of the document3is discontinued.

The CPU401then interpolates the edge of the document3through a known method, such as the morphology transformation. Thus, an image illustrated inFIG.17Cis generated. As a result, only the edge of the transparent document folder is deleted.

Thereafter, the CPU401performs, on the image illustrated inFIG.17C, detection of a document edge candidate and determination of a document edge described in the first exemplary embodiment.

The above-described configuration enables appropriate cut out of documents even if a document partly lies off the transparent document folder.

The configurations according to the first to the fourth exemplary embodiments are also applicable to a sheet (mount) on which a plurality of documents is mounted.

According to the present disclosure, it is possible to provide an image reading apparatus capable of easily cutting out individual images of documents from an image that includes the individual images of the documents.

This application claims the benefit of priority from Japanese Patent Application No. 2021-199624, filed Dec. 8, 2021, which is hereby incorporated by reference herein in its entirety.