Reading device, image processing device, reading method, and program

Abstract

To determine the width of a subject in a main scanning direction even when the subject exceeds a detectable range.SOLUTION: A device includes an illumination unit that irradiates a subject with light, an imaging unit that receives light reflected by the subject and generates an image, an edge detection unit that detects the edge of the subject, and a size determination unit that determines the size of the subject according to the detection result of the edge detection unit.The size determination unit determines the width of the subject in a main scanning direction when the edge detection unit does not detect upper or lower edges of both ends of the subject in the main scanning direction of the imaging unit, and determines that the width of the subject in the main scanning direction is determined as a predetermined width when the edge detection unit detects the upper or lower edges of both ends of the subject in the main scanning direction of the imaging unit.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to a reading device, an image processing device, a reading method, and a program.

Background Art

[0002] Conventionally, for the purpose of eliminating a decrease in reading quality caused by the inclination and positional deviation of a document, a technique is known in which the inclination of the document portion is determined from the read image data, the inclination of the document portion is corrected, and the document portion is cut out.

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, according to the conventional technology, when an image reading sensor or an optical system having a limited detection range in the main scanning area is provided, if the document exceeds the width of the main scanning area, the edge portion of the document cannot be detected. There is also a problem that when a sensor or the like with a wide detection range is used for the purpose of expanding the detection range of the main scanning area, the housing becomes large or the cost becomes high.

[0004] The present invention has been made in view of the above, and an object thereof is to be able to determine the width of a subject in the main scanning direction even when the subject exceeds the detectable range.

Means for Solving the Problems

[0005] In order to solve the above-described problems and achieve the object, the present invention includes an illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, an edge detection unit that detects an edge of the subject, and a size determination unit that determines the size of the subject according to a detection result of the edge detection unit. The size determination unit determines the width of the subject in the main scanning direction when the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit is not detected by the edge detection unit, and makes a determination to regard the width of the subject in the main scanning direction as a predetermined width when the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit is detected by the edge detection unit. This is the gist of the present invention.

Effect of the Invention

[0006] According to the present invention, even when the subject exceeds the detectable range, it is possible to determine the width of the subject in the main scanning direction.

Brief Description of the Drawings

[0007]

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[0008] Hereinafter, embodiments of a reading apparatus, an image processing apparatus, a reading method, and a program will be described in detail with reference to the accompanying drawings.

[0009] (First Embodiment) FIG. 1 is a diagram showing the configuration of an example of an image forming apparatus 1 according to the first embodiment. In FIG. 1, an image forming apparatus 1 which is an image processing apparatus is generally called a multi-functional device having at least two functions among a copying function, a printer function, a scanner function, and a facsimile function.

[0010] The image forming apparatus 1 has an image reading apparatus 101 which is a reading apparatus, and has an image forming unit 103 below it. Regarding the image forming unit 103, in order to explain the internal configuration, the external cover is removed to show the internal configuration.

[0011] The image reading apparatus 101 mounts an ADF (Automatic Document Feeder) 102 on the upper part of the apparatus main body 10. The ADF 102 is a document support unit that positions a document to be read at a reading position. The ADF 102 automatically conveys the document placed on the placement table to the reading position. The image reading apparatus 101 reads the document conveyed by the ADF 102 at a predetermined reading position. Further, the image reading apparatus 101 has a contact glass which is a document support unit for placing a document on its upper surface, and reads the document on the contact glass which is the reading position. Specifically, the image reading apparatus 101 is a scanner having a light source, an optical system, and a solid-state imaging device such as a CMOS image sensor inside, and reads the reflected light of the document illuminated by the light source with the solid-state imaging device through the optical system.

[0012] The image forming unit 103 has a manual feed roller 104 that accepts manual feeding of recording paper, and a recording paper supply unit 107 that supplies recording paper. The recording paper supply unit 107 has a mechanism for feeding out recording paper from a multi-stage recording paper feed cassette 107a. The supplied recording paper is sent to a secondary transfer belt 112 via a registration roller 108.

[0013] The recording paper conveyed on the secondary transfer belt 112 has a toner image on the intermediate transfer belt 113 transferred thereto at the transfer unit 114.

[0014] In addition, the image forming unit 103 includes an optical writing device 109, tandem type image forming units (Y, M, C, K) 105, an intermediate transfer belt 113, the secondary transfer belt 112, and the like. The image forming unit 103 forms the image written by the optical writing device 109 as a toner image on the intermediate transfer belt 113 through the image forming process by the image forming unit 105.

[0015] Specifically, the image forming units (Y, M, C, K) 105 rotatably include four photosensitive drums (Y, M, C, K), and each photosensitive drum is provided with an image forming element 106 including a charging roller, a developing device, a primary transfer roller, a cleaner unit, and a discharger around it. The image forming element 106 functions on each photosensitive drum, and the image on the photosensitive drum is transferred onto the intermediate transfer belt 113 by each primary transfer roller.

[0016] The intermediate transfer belt 113 is stretched and arranged between the nips of each photosensitive drum and each primary transfer roller by a driving roller and a driven roller. The toner image primarily transferred onto the intermediate transfer belt 113 is secondarily transferred onto the recording paper on the secondary transfer belt 112 by the running of the intermediate transfer belt 113. The recording paper is conveyed to the fixing device 110 by the running of the secondary transfer belt 112, and the toner image is fixed as a color image on the recording paper. Thereafter, the recording paper is discharged to the paper discharge tray outside the machine. In the case of double-sided printing, the front and back of the recording paper are reversed by the reversing mechanism 111, and the reversed recording paper is sent onto the secondary transfer belt 112.

[0017] Note that the image forming unit 103 is not limited to forming an image by the electrophotographic method as described above, and may form an image by an inkjet method.

[0018] Next, the image reading device 101 will be described.

[0019] FIG. 2 is a diagram showing an example of the device configuration of the image reading apparatus 101. The apparatus main body 10 of the image reading apparatus 101 has a contact glass 11 on its upper surface. Inside the apparatus main body 10, the image reading apparatus 101 has a light source 13, a first carriage 14, a second carriage 15, a lens unit 16, a sensor board 17, and the like. In FIG. 2, the first carriage 14 has a light source 13 and a reflection mirror 14-1, and the second carriage 15 has reflection mirrors 15-1 and 15-2.

[0020] The light from the light source 13 is irradiated onto the object to be read, and the reflected light from the object to be read is reflected by the mirror 14-1 of the first carriage 14 and the mirrors 15-1 and 15-2 of the second carriage 15 and then enters the lens unit 16, and an image of the object to be read is formed on the light receiving surface on the sensor board 17 from the lens unit 16. The sensor board 17 has an imaging unit 40 which is a line sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary MOS). The sensor board 17 sequentially converts the image of the object to be read formed on the light receiving surface in the imaging unit 40 into an electrical signal. The reference white board 12 is a white density reference member that is read for correction of, for example, changes in the light amount of the light source 13 and variations in the pixels (pixel circuits) of the imaging unit 40.

[0021] The image reading apparatus 101 is provided with a control board in the apparatus main body 10, and controls each part of the apparatus main body 10 and each part of the ADF 102 to read the object to be read in a predetermined reading method. The object to be read is, for example, a recording medium on which characters, patterns, or the like are formed. Hereinafter, this recording medium will be referred to as a document. The document corresponds to the "subject", and is described as paper or a transparent sheet (such as an OHP sheet) as an example, but is not limited thereto.

[0022] The image reading device 101 reads the document 100 in a sheet-through manner using the ADF 102. The ADF 102 is an example of a "transport unit". In the configuration shown in FIG. 2, the image reading device 101 separates the documents 100 one by one from the stack of documents on the tray 21 of the ADF 102 by the pickup roller 22, transports the document 100 to the transport path 23, reads the surface of the document 100 to be read at the reading position of the reading unit, and discharges the document 100 to the discharge tray 25. The transport of the document 100 is performed by the rotation of various transport rollers 24.

[0023] Among the various transport rollers 24, a pair of rollers that perform primary abutment alignment (so-called skew correction) on the fed document 100 and pull out and transport the aligned document 100 are called pull-out rollers 24a. A butting sensor 51 is provided near the pull-out rollers 24a.

[0024] The tray 21 has a movable document table 211 that rotates in the a and b directions in the figure with the base end as a fulcrum, and a pair of side fences 212 that position the document 100 in the left-right direction with respect to the paper feed direction. By rotating the movable document table 211, the front end of the document 100 in the paper feed direction is adjusted to an appropriate height.

[0025] In addition, document length detection sensors 213 and 214 for detecting whether the document 100 is in the vertical or horizontal orientation are provided at intervals in the paper feed direction on the tray 21. Note that as the document length detection sensors 213 and 214, a reflection type sensor that detects without contact by optical means or a contact type actuator type sensor may be used.

[0026] The pair of side fences 212 are slidable in the left-right direction with respect to the paper feed direction and are configured to be able to support documents 100 of different sizes. A document set sensor 215 for detecting that the document 100 is placed on the tray 21 is provided on the pair of side fences 212.

[0027] In addition, a document width sensor 52 as a detection sensor is provided in the transport path 23 on the downstream side in the document transport direction of the pull-out rollers 24a.

[0028] Here, FIG. 3 is a diagram showing an example of the arrangement of the document width sensor 52. As shown in FIG. 3, the document width sensor 52 includes, as an example, light receiving elements (52a, 52b, 52c) arranged in the width direction of the document 100 in accordance with the size of the standard document of each document 100 from the side fence 212 serving as a document placement reference. The document width sensor 52 detects the document width of the document 100 based on the light reception result from the irradiation light provided at opposing positions across the conveyance path 23. Note that the length of the document 100 in the conveyance direction is detected from the motor pulses when the leading end and the trailing end of the document 100 are read by the abutting sensor 51 provided near the pull-out roller 24a.

[0029] The image reading apparatus 101 passes the document 100 between the reading window 19 and the background portion 26 with, for example, the first carriage 14 and the second carriage 15 moved to and fixed at a predetermined home position. The reading window 19 is a slit-shaped reading window provided in a part of the contact glass 11. The background portion 26 is a member located at a position facing the reading window 19. The reading unit irradiates the light of the light source 13 onto the first surface (front surface or back surface) of the document 100 facing the reading window 19 while the document 100 passes through the reading window 19, and receives the reflected light by the imaging unit 40 on the sensor board 17 to read an image. The background portion 26 may have a size such that it is included in the imaging range of the imaging unit 40, and is, for example, a sheet metal or a roller.

[0030] Here, the light source 13, the background portion 26, the optical system (mirrors 14-1, 15-1, 15-2, lens unit 16, etc.) that guides the reflected light from the document 100 to the imaging unit 40 of the sensor board 17, and the imaging unit 40, etc. will be described as the reading unit (first reading unit). The configuration of the reading unit will be described again with reference to FIG. 5.

[0031] When performing double-sided reading of the document 100, for example, it is implemented by providing a reversing mechanism for reversing the front and back sides. The image reading device 101 reverses the document 100 by providing a reversing mechanism and causes the second side of the document 100 to be read at the reading position (reading window 19) of the reading unit. Also, not limited to the reversing mechanism, the second side may be read by providing other configurations, for example, by providing a second reading unit. For example, after passing through the reading window 19, the second side of the document 100 is read by a reading unit (second reading unit) provided on the back side of the document 100 with a reading sensor. In this case, the member at the position facing the reading sensor corresponds to the background portion 26 (see FIG. 4).

[0032] In the configuration of the image reading device 101 of this example, flatbed reading is also possible. Specifically, the ADF 102 is lifted to expose the contact glass 11, and the document 100 is directly placed on the contact glass 11. Then, the ADF 102 is lowered to its original position and the back side of the document 100 is pressed at the lower part of the ADF 102. In the flatbed method, since the document 100 is fixed, scanning is performed by moving the carriage (first carriage 14, second carriage 15) side with respect to the document 100. The first carriage 14 and the second carriage 15 are driven by the scanner motor 18 and scan in the sub-scanning direction of the document 100. For example, the first carriage 14 moves at a speed V, and at the same time, the second carriage 15 moves at a speed of 1 / 2V, which is half of the speed of the first carriage 14, in conjunction with it, to read the first side of the document 100 on the contact glass 11 side. In this case, the lower part of the ADF 102 (the member that presses the document 100 from the back) corresponds to the background portion 26 (see FIG. 4).

[0033] Note that in this example, the first carriage 14, the second carriage 15, the lens unit 16, the sensor board 17, etc. are shown separately, but these may be provided individually or as an integrated sensor module integrated together.

[0034] FIG. 4 is a diagram for explaining an example of the configuration of the reading unit 30. As an example, it shows the configuration of the reading unit 30 (first reading unit) that reads the first side of the document 100 and the transport mechanism. As shown in FIG. 4, the document 100 is sent by various transport rollers 24 and passes between the reading position (reading window 19) of the contact glass 11 and the background portion 26.

[0035] The reading unit 30 has a background portion 26 set therein. When the light source 13 is lit, while the document 100 passes through the reading window 19, the reflected light of the light from the light source 13 from the first side of the document 100 directed toward the reading window 19 is received by the imaging unit 40 on the sensor board 17 via the path indicated by the dotted line in FIG. 4, and an image is read.

[0036] Note that the configuration of the reading unit is not limited to the configuration of this first reading unit. It may be appropriately modified according to the method of reading with a close-contact type image sensor like the second reading unit or other configurations of the image reading device.

[0037] As shown in FIG. 4, the light source 13 of the present embodiment is composed of a visible light source 13a and an invisible light source 13b, and is an illumination unit that irradiates a subject with visible light and invisible light. The visible light source 13a irradiates the subject and the background portion 26 with visible light. The invisible light source 13b irradiates the subject and the background portion 26 with invisible light. It is effective to use infrared light as the invisible light source 13b. Generally, the visible light wavelength range is 380 to 750 nm, and 750 nm and above is the infrared wavelength range, which is the wavelength range of invisible light.

[0038] Note that in the present embodiment, the invisible light source 13b is assumed to irradiate invisible light in the infrared wavelength range of 750 nm or more, but it is not limited thereto, and it may irradiate invisible light in the ultraviolet wavelength range of 380 nm or less.

[0039] FIG. 5 is a block diagram showing the electrical connections of the respective components constituting the image reading apparatus 101. As shown in FIG. 5, the image reading apparatus 101 includes, in addition to the imaging unit 40 and the light source 13 described above, a control unit 41, a light source driving unit 42, and an image processing unit 43. The control unit 41 controls the imaging unit 40, the light source driving unit 42, and the image processing unit 43. The light source driving unit 42 drives the light source 13 in accordance with the control of the control unit 41. The imaging unit 40 transfers signals to the image processing unit 43 arranged at the subsequent stage.

[0040] The imaging unit 40 includes an invisible light image sensor 40b that functions as an invisible image reading unit and a visible light image sensor 40a that functions as a visible image reading unit. The imaging unit 40 receives visible light and invisible light reflected by a subject, and captures a visible image and an invisible image. More specifically, the invisible light image sensor 40b reads invisible reflected light from a subject, which is a part of invisible light, to acquire an invisible image (an image in the invisible light wavelength region). The visible light image sensor 40a reads visible reflected light from a subject, which is a part of visible light, to acquire a visible image (an image in the visible light wavelength region). The invisible light image sensor 40b and the visible light image sensor 40a are sensors for a reduction optical system, and are, for example, CMOS image sensors.

[0041] Note that the visible light image sensor 40a and the invisible light image sensor 40b may have an integrated configuration. As a result, a smaller configuration can be achieved, and the reading positions of visible light and infrared light are closer, enabling highly accurate extraction and restoration of disappearing information. That is, there is no image shift due to multiple readings, and correction can be performed with high positional accuracy.

[0042] The image processing unit 43 executes various types of image processing according to the purpose of use of the image data. Note that the image processing unit 43 may be realized by a hardware circuit or may be realized by a CPU executing a program.

[0043] Here, FIG. 6 is a block diagram showing the functional configuration of the image processing unit 43. As shown in FIG. 6, the image processing unit 43 includes a feature quantity detection unit 431 and a size determination unit 432. The image processing unit 43 detects the feature quantity of the subject or the background portion 26 by the feature quantity detection unit 431 from at least one of the visible image and the invisible image obtained by the reading device main body 10. Examples of the feature quantity include, for example, an edge between the background portion 26 and the document 100. The image processing unit 43 uses the detected feature quantity for the correction processing of the image itself, although the details will be described later.

[0044] The feature quantity detection unit 431 functions as an edge detection unit that detects the edge of the subject. More specifically, the feature quantity detection unit 431 detects an edge by methods such as detecting an edge from the density difference between the read document 100 and the background portion 26 or detecting a shadow between the document 100 and the background portion 26. Here, edge detection means detecting the boundary between the document 100 and the background.

[0045] The size determination unit 432 receives the detection result of the feature quantity detection unit 431 and determines the size of the document. More specifically, when the upper edge at both ends of the document 100 in the main scanning direction X (see FIG. 15 etc.) is not detected by the feature quantity detection unit 431 (the document 100 is smaller than the detectable range), the size determination unit 432 determines the width of the document 100 in the main scanning direction X (hereinafter referred to as the main scanning width). Further, when the upper edge at both ends of the document 100 in the main scanning direction X is detected by the feature quantity detection unit 431 (the document 100 is larger than the detectable range), the size determination unit 432 makes a determination to regard the main scanning width of the document 100 as a predetermined width (for example, A3 width).

[0046] Here, the difference in the spectral reflection characteristics due to the medium in the imaging unit 40 will be described.

[0047] FIG. 7 is a diagram showing differences in spectral reflection characteristics due to the medium. FIG. 7 is a diagram showing the spectral reflection characteristics of two types of plain paper, Paper Type A and Paper Type B, which are generally used as originals and are the objects to be read by the image reading apparatus 101, and the background portion 26. In FIG. 7, the graph of the one-dot chain line is the graph of the spectral reflection characteristics of plain paper (Paper Type A), the graph of the dotted line is the graph of the spectral reflection characteristics of plain paper (Paper Type B), and the graph of the solid line is the graph of the spectral reflection characteristics of the background portion 26.

[0048] As shown in FIG. 7, in the visible wavelength range, the reflectance of the background portion 26, which is a white background, is higher than that of plain paper (Paper Type A), but in the near-infrared (NIR) wavelength range, the reflectance of the background portion 26 is lower than that of plain paper (Paper Type A).

[0049] Also, as shown in FIG. 7, it can be seen that the reflectance of the background portion 26 is higher than that of plain paper (Paper Type B) in any region of the visible wavelength range and the near-infrared (NIR) wavelength range.

[0050] Here, FIG. 8 is a diagram exemplarily showing the difference between a visible image and an invisible image. As shown in FIG. 8, when the reflected light is read by the imaging unit 40, the spectral reflection characteristics are different between the background portion 26 and the original, and images having different feature amounts are obtained for visible light and invisible light. Therefore, it is easy to obtain the target feature amount by presetting the image to be detected as either a visible image or an invisible image according to the type of the subject and the type of the background portion 26.

[0051] For example, in the case of the example shown in FIG. 8, since the difference in spectral reflection characteristics between Paper Type A and the background portion 26 is larger in the invisible image than in the visible image, the detection target of the feature amount can be set as the invisible image, and conversely, Paper Type B can be set as the visible image.

[0052] Note that the feature amounts may be extracted from both the visible image and the invisible image, and then selected or integrated from the results.

[0053] Subsequently, the feature amount detection unit 431 will explain an example of edge detection of the original 100 as the subject and an example of correction of the inclination and position of the original.

[0054] FIG. 9 is a diagram showing an example of edge detection of a subject, FIG. 10 is a diagram showing an example of correction of the inclination and position of a document, and FIG. 11 is a diagram showing information obtained from the edge of a subject. For example, as shown in FIG. 9, when extracting an edge between the background portion 26 and the document 100 from an image, it is preferable to reduce the reflectance of the background portion 26 and use an invisible image. Also, as shown in FIG. 10, when correcting the inclination and position of the document and cropping the document image, it is preferable to reduce the reflectance of the background portion 26 and use an invisible image. When reading with invisible light in this way, since the invisible light reflectance of the background portion 26 is low, a bright image of the document 100 and a dark image of the background portion 26 are obtained. Since the difference between the document 100 and the background portion 26 can be clearly seen, edges are easily detected. That is, the density difference between the document 100 and the background portion 26 can be widened, and edge detection can be performed with higher accuracy.

[0055] As shown in FIG. 11, an edge refers to the boundary between the document 100, which is the subject, and the background portion 26. By detecting such an edge, as shown in FIG. 11, the position, inclination, size, etc. of the document 100, which is the subject, can be recognized. And from the position, inclination, and size of the document 100, which is the subject, image correction corresponding to the position, inclination, and size of the document 100, which is the subject, can also be performed in subsequent processing.

[0056] FIG. 12 is a diagram exemplarily showing a method of edge detection. As a method of edge detection, as shown in FIG. 12(a), for example, a method of applying a first-order differential filter to the entire image and binarizing according to whether each pixel exceeds a predetermined threshold value can be mentioned. At that time, depending on the threshold value, horizontal edges appear continuously vertically by several pixels (the reverse is also true). This is mainly because the edge is blurred due to the MTF characteristics of the optical system. Therefore, as shown in FIG. 12(b), in order to obtain representative edge pixels for calculating a regression line formula and size detection, which will be described later, there is a method of selecting, for example, the center of continuous pixels (part a shown in FIG. 12(b)).

[0057] FIG. 13 is a diagram showing an example of a feature amount using an edge. The feature amount may not be the edge itself extracted from the image, but may be one using the edge. As an example, as shown in FIG. 13, a regression line equation calculated using the least squares method or the like from the extracted edge point group, and a region (set of positions) inside the edge can be mentioned. Regarding the regression line equation, there is a method of obtaining one linear equation from all edge information for each side, but there is also a method of calculating linear equations by dividing into a plurality of regions and selecting or integrating representative ones. In that case, as methods for deriving the final linear equation, a straight line with the median as the slope and a method of obtaining the average value of each linear equation can be mentioned.

[0058] FIG. 14 is a diagram showing the selection of a linear equation in the regression line equation. By calculating linear equations by dividing into a plurality of regions and selecting or integrating representative ones, as shown in FIG. 14, even when there is damage such as a missing edge of the document 100 as the subject, the inclination of the document 100 as the subject can be correctly recognized.

[0059] As in the above processing, the feature amount detection unit 431 can detect the region of the document 100 as the subject by extracting the edge of the document 100 as the subject as a feature amount.

[0060] By the way, as described above, the image reading apparatus 101 of the present embodiment can detect the width of the document 100 using the document width sensor 52.

[0061] As shown in FIG. 3, the document width sensor 52 is composed of a plurality of light receiving elements (52a, 52b, 52c) arranged at predetermined intervals in the width direction of the document 100 as an example. The light receiving elements (52a, 52b, 52c) of the document width sensor 52 are placed at positions where it is possible to determine the size of the standard-sized document 100. Therefore, when a standard-sized document 100 is passed through, the document size of the document 100 is determined from the position information of the light receiving elements of the document width sensor 52 that have reacted.

[0062] Here, problems in the conventional size detection of the document 100 will be described.

[0063] FIG. 15 is a diagram showing an example of reading an irregular-sized document 100. In the drawings shown below, in the figure, the main scanning direction of the imaging unit 40 is X and the document conveyance direction is Y. As described above, according to the prior art, when reading an irregular-sized document 100, instead of specifying the size to be read by user operation or the like, the size is automatically determined when reading the document 100. Therefore, when the size is determined at one end where the document width sensor 52 is installed, there may be an incorrect determination depending on the state of the document 100.

[0064] For example, as shown in FIG. 15(a), if the A3-width document 100 is placed at the document placement reference position for detecting the size of the document 100 such as the side fence 212 and read, it is possible to detect the A3-width document 100 as A3 width.

[0065] However, as shown in FIG. 15(b), when the A4-width document 100 is not placed at the document size detection document placement reference position or when the A4-width document 100 is tilted, an incorrect determination is made as an A3-width document 100 even though it is an A4-width document 100.

[0066] Therefore, in order to suppress the above incorrect determination, the size determination unit 432 of the image processing unit 43 of the present embodiment adopts a configuration in which the left and right ends of the document 100 are detected from the image data instead of one end of the document 100 to determine the size of the document 100.

[0067] Here, FIG. 16 is a diagram showing an execution example of edge detection of the upper side of the document 100 from the image data. As shown in FIG. 16, the size determination unit 432 receives the detection result of the feature amount detection unit 431 and determines the size of the document 100.

[0068] More specifically, when the detectable range in the main scanning direction X of the imaging unit 40 is, for example, 7016 pixels, the size determination unit 432 determines whether the output levels of the upper sides of the original document 100 near both ends in the main scanning direction X of the image data indicated by the ellipse in FIG. 16 are below a threshold value (such as the level of the reference white plate 12).

[0069] When the size determination unit 432 determines that the output levels of the upper sides of the original document 100 near both ends in the main scanning direction X of the image data indicated by the ellipse in FIG. 16(a) are below a threshold value (such as the level of the reference white plate 12), that is, when the upper side edges at both ends of the original document 100 in the main scanning direction X are detected by the feature amount detection unit 431, it is determined that the main scanning width of the original document 100 exceeds 7016 pixels, and a determination is made to regard the main scanning width of the original document 100 as a fixed size (for example, A3 width).

[0070] FIG. 16(b) is a diagram showing an example when the upper side edges at both ends in the main scanning direction X are detected due to the inclination of the original document. When a part of the upper side edge is in the detection area due to the inclination of the original document as shown at the right end of FIG. 16(b), for example, it is regarded that the upper side edge is detected on the condition that the upper side edge occupies a certain ratio with respect to the detection area. That is, when the upper side edges at both ends of the original document 100 in the main scanning direction X are detected by the feature amount detection unit 431, it is determined that the main scanning width of the original document 100 exceeds 7016 pixels, and a determination is made to regard the main scanning width of the original document 100 as a fixed size (for example, A3 width).

[0071] Here, FIG. 17(a) is a diagram showing an example where the upper edge is not detected at both ends in the main scanning direction X by image detection. FIG. 17(b) is a diagram showing an example where the document is not detected at both ends in the main scanning direction X by the document width sensor. As shown in FIG. 17(a) or (b), when the size of the document 100 does not exceed a certain size (detectable range) and the upper edges at both ends in the main scanning direction X are not detected, the upper edges other than those at both ends in the main scanning direction X of the document 100 are detected, and the size of the main scanning width of the document 100 is determined based on the detection result. Further, FIG. 17(c) is a diagram showing an example where one of the upper edges at both ends in the main scanning direction X is not detected by image detection. FIG. 17(d) is a diagram showing an example where the document is not detected at one of both ends in the main scanning direction X by the document width sensor. When one of the upper edges at both ends in the main scanning direction X of the document 100 is not detected, the upper edges other than those at both ends in the main scanning direction X of the document 100 are detected, and the size of the main scanning width of the document 100 is determined based on the detection result.

[0072] In this embodiment, since the upper edge in the main scanning direction X of the document 100 can be detected, for example, compared with the case where the document width sensor is arranged only on one side in the main scanning direction X, the upper edges at both ends in the main scanning direction X of the document 100 are detected, so that size misdetection when reading an irregularly sized document 100 can be prevented, and the main scanning width can be accurately determined.

[0073] Note that in this embodiment, the main scanning width of the document 100 is determined based on the output levels of the upper sides near both ends in the main scanning direction X of the image data of the document 100, but it is not limited to this, and the main scanning width of the document 100 may be determined based on the output levels of the lower sides near both ends in the main scanning direction X of the image data of the document 100.

[0074] Next, the flow of the size determination process executed by the size determination unit 432 of the image reading apparatus 101 will be described.

[0075] Here, FIG. 18 is a flowchart showing the flow of the size determination process. As shown in FIG. 18, the image reading apparatus 101 controls the reading unit 30 to read a document (step S1).

[0076] Next, the image reading apparatus 101 controls the feature amount detection unit 431 of the image processing unit 43 to detect the upper edge of both ends in the main scanning direction X of the read document image (step S2).

[0077] If the image reading apparatus 101 determines that the upper edge of both ends in the main scanning direction X of the document 100 cannot be detected by the feature amount detection unit 431 (No in step S2), it determines that the document 100 is smaller than the detectable range, and controls the size determination unit 432 to determine the main scanning width of the document 100 from the detection result (step S3).

[0078] On the other hand, if the image reading apparatus 101 determines that the upper edge of both ends in the main scanning direction X of the document 100 can be detected by the feature amount detection unit 431 (Yes in step S2), it determines that the document 100 is larger than the detectable range, and controls the size determination unit 432 to perform a determination assuming the main scanning width of the document 100 as a fixed size (for example, A3 width) (step S4).

[0079] Thus, according to this embodiment, when the upper edge of both ends in the main scanning direction X of the subject is detected by the feature amount detection unit (the document 100 is larger than the detectable range), the size determination unit makes a determination assuming the main scanning width of the subject as a predetermined width. Thereby, even when the subject exceeds the detectable range, the main scanning width of the subject can be determined, so that, for example, the size of the subject can be cut out.

[0080] (Second Embodiment) Next, the second embodiment will be described.

[0081] The second embodiment is different from the first embodiment in which edge detection is performed from an image in that edge detection is performed based on detection by the document width sensor 52. Since the detection by the document width sensor 52 also changes the on / off of the signal depending on the presence or absence of the document, it can be said that an edge is detected. Hereinafter, in the description of the second embodiment, the description of the same parts as those of the first embodiment will be omitted, and the parts different from the first embodiment will be described.

[0082] Here, FIG. 19 is a diagram showing an arrangement example of the document width sensor 52 in the image reading apparatus 101 according to the second embodiment, and FIG. 20 is a diagram showing an edge detection example in the image reading apparatus 101.

[0083] As shown in FIG. 19, the document width sensor 52 in the image reading apparatus 101 of the present embodiment has a plurality of light receiving elements (52a, 52b, 52c, 52d, 52e, 52f) arranged separately on the left and right of the conveyance path 23 according to the size of the standard document of each document 100. For example, when the detectable range of the imaging unit 40 is 7016 pix, for example, in the case of ADF reading, the document width sensor 52 is arranged near both ends of the left and right sides of the detectable range in the conveyance path of the document 100.

[0084] In the case of flatbed reading, the document width sensor 52 may be arranged such that a plurality of rows of light receiving elements in the main scanning direction are arranged near both ends of the left and right sides of the detectable range in the reading area of the document 100 according to the size of the standard document of each document 100.

[0085] The size determination unit 432 determines whether the width of the document in the conveyance path or the reading area exceeds the detectable range by the document width sensor 52, and also determines the size of the document.

[0086] When the width of the document 100 in the conveyance path or the reading area does not exceed the detectable range by the document width sensor 52, the size determination unit 432 determines the size, which is the main scanning width of the document 100, based on the width of the upper edge in the main scanning direction X of the document 100 in the image data.

[0087] As shown by the circles in Fig. 20(a), when the upper edge of the document 100 is detected by both the left and right document width sensors 52 (when the document 100 is larger than the detectable range), the size determination unit 432 determines that the main scanning width of the document 100 exceeds 7016 pix, and executes a determination to regard the main scanning width of the document 100 as a fixed size (for example, A3 width).

[0088] Also, as shown by the circles in Fig. 20(b), when the upper edge of the document 100 is detected by both the left and right document width sensors 52 due to the document being tilted (when the document 100 is larger than the detectable range), the size determination unit 432 also executes a determination to regard the main scanning width of the document 100 as a fixed size (for example, A3 width).

[0089] Thus, according to this embodiment, when the upper edge at both ends in the main scanning direction X of the subject is detected by the document width sensor 52 (when the document 100 is larger than the detectable range), the size determination unit makes a determination to regard the main scanning width of the subject as a predetermined width. Thereby, even when the subject exceeds the detectable range, the main scanning width of the subject can be determined, so that, for example, the subject can be cropped according to its size.

[0090] (Third Embodiment) Next, the third embodiment will be described.

[0091] The third embodiment is different from the first embodiment in which edge detection is performed only from an image in that edge detection from the image and edge detection based on detection by the document width sensor 52 are used in combination. Hereinafter, in the description of the third embodiment, the description of the same parts as those in the first embodiment will be omitted, and the parts different from the first embodiment will be described.

[0092] Here, Fig. 21 is a diagram showing an example of edge detection in the image reading apparatus 101 according to the third embodiment.

[0093] As shown in FIG. 4, the image reading apparatus 101 includes a document width sensor 52 on one side. For example, when the detectable range of the imaging unit 40 is 7016 pix, in the case of ADF reading, the document width sensor 52 is arranged near one end of either the left or right side of the detectable range in the conveyance path of the document 100 (in this embodiment, near the right side end of the detectable range).

[0094] In the case of flatbed reading, the document width sensor 52 may be arranged near one end of either the left or right side of the detectable range in the reading area of the document 100 (in this embodiment, near the right side end of the detectable range), and a plurality of rows of light receiving elements in the main scanning direction may be arranged according to the size of the standard document of each document 100.

[0095] The size determination unit 432 receives the detection result of the document width sensor 52 and the detection result of the feature amount detection unit 431, and determines the size of the document 100.

[0096] When the size determination unit 432 determines that the output level of the upper side near the left side end of the document 100 in the image data is not less than the threshold value (such as the level of the reference white plate 12), and the width of the document 100 is not detected near the right side end of the detectable range in the conveyance path or the reading area by the document width sensor 52, that is, when the upper side edges at both ends of the document 100 in the main scanning direction X are not detected, the size which is the main scanning width of the document 100 is determined based on the width of the edges at both ends in the main scanning direction X.

[0097] On the other hand, as shown by the circled marks in FIG. 21(a), when the size determination unit 432 determines that the width of the document near the right side end of the detectable range in the conveyance path or the reading area by the document width sensor 52 exceeds the detectable range, and the output level of the upper side near the left side end of the document 100 in the main scanning direction X of the image data shown by the elliptical marks in FIG. 21(a) is not less than the threshold value (such as the level of the reference white plate 12), that is, when the upper side edges at both ends of the document 100 in the main scanning direction X are detected, it is determined that the main scanning width of the document 100 exceeds 7016 pix, and a determination is executed to regard the main scanning width of the document 100 as a fixed size (for example, A3 size).

[0098] Further, as shown by the circled marks in FIG. 21(b), when the size determination unit 432 determines that the width of the document 100 near the right-side end of the detectable range in the conveyance path or the reading area by the document width sensor 52 exceeds the detectable range due to the inclination of the document 100, and the output level of the upper side near the left-side end in the main scanning direction X of the document 100 of the image data indicated by the oval marks in FIG. 21(b) is equal to or lower than the threshold value (such as the level of the reference white plate 12), that is, when the upper side edges at both ends in the main scanning direction X of the document 100 are detected, the main scanning width of the document 100 is determined as a fixed size (for example, A3 size).

[0099] That is, the image reading apparatus 101 of the present embodiment arranges the document width sensor 52 only on one side of the left and right sides to detect the presence or absence of a document, and detects the upper side edge of the end area of the read image data on the other side.

[0100] As described above, according to the present embodiment, when the upper side edges at both ends in the main scanning direction X of the subject are detected by the feature amount detection unit 431 and the document width sensor 52 (the document 100 is larger than the detectable range), the size determination unit determines that the main scanning width of the subject is a predetermined width. Thereby, even when the subject exceeds the detectable range, the main scanning width of the subject can be determined, so that, for example, the size of the subject can be cut out.

[0101] Further, according to the present embodiment, the cost can be reduced compared to arranging the document width sensors 52 on both end sides in the main scanning direction X, so that both cost and function can be achieved.

[0102] The program executed in the image forming apparatus 1 of each of the above embodiments is provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disc) in an installable format or an executable format file.

[0103] Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be configured to be provided or distributed via a network such as the Internet. Further, the program executed by the image forming apparatus 1 of each of the above embodiments may be configured to be provided by being pre - incorporated into a ROM or the like.

[0104] The program executed by the image forming apparatus 1 of each of the above embodiments has a module configuration including the above - described respective parts (feature quantity detection unit 431, size determination unit 432). As actual hardware, the CPU (processor) reads the program from the above - described storage medium and executes it, whereby the above - described respective parts are loaded onto the main storage device, and the feature quantity detection unit 431 and the size determination unit 432 are generated on the main storage device.

[0105] In each of the above embodiments, an example in which the reading device of the present invention is applied to a multifunction device having at least two functions among a copying function, a printer function, a scanner function, and a facsimile function has been described. However, the present invention can be applied to any image forming device such as a copying machine, a printer, a scanner device, or a facsimile device.

[0106] In each of the above embodiments, the image reading device 101 of the image forming apparatus 1 is applied as the reading device, but the present invention is not limited thereto. As the definition of the reading device, it may be a device that can acquire a reading level, such as the line sensor of the 1:1 optical system (contact optical system: CIS method) shown in FIG. 22(a), even if it does not read as an image. The device shown in FIG. 22(a) is a line sensor or a device that moves the document to read information of a plurality of lines.

[0107] Furthermore, as a reading device, it can also be applied to the banknote conveying device shown in Fig. 22(b), the white line detection device of the automated guided vehicle (AGV) shown in Fig. 22(c), etc.

[0108] The subject of the banknote conveying device shown in Fig. 22(b) is a banknote. The feature amount detected by the banknote conveying device is used for correction processing of the image itself, etc. That is, the banknote conveying device shown in Fig. 22(b) recognizes the inclination of the banknote by edge detection and performs skew correction using the recognized inclination.

[0109] The subject of the white line detection device of the automated guided vehicle shown in Fig. 22(c) is a white line. The feature amount detected by the white line detection device of the automated guided vehicle can be used for determining the moving direction of the automated guided vehicle, etc. That is, the white line detection device of the automated guided vehicle recognizes the inclination of the white line area by edge detection and determines the moving direction of the automated guided vehicle using the recognized inclination. Also, in the white line detection device of the automated guided vehicle, moving direction correction according to the position and orientation of the automated guided vehicle can be performed in subsequent processing. For example, in the case of an automated guided vehicle, processing such as stopping the drive when a thickness different from the known thickness of the white line is detected is also executable.

[0110] Fig. 23 is a diagram showing another modification example of the reading device. The example shown in Fig. 23 shows an application example to the image reading device 200 used at the time of packaging goods such as in a production site as a reading device.

[0111] The subjects of the image reading device 200 shown in Fig. 23 are packages A, B, and C of different sizes that are goods to be transported. As shown in Fig. 23, when packages A, B, and C of different sizes are conveyed by the belt conveyor 201, the width of the packages can be detected by detecting the feature amounts (edges) of packages A, B, and C by the image reading device 200 of the present invention. When detecting the feature amounts of packages A, B, and C, visible light is effective for black packages, and invisible light is effective for white packages.

[0112] Note that in this case, the background portion 26 may be the surface of the belt conveyor 201, or a dedicated background portion 26 may be arranged with the reading position of the image reading device 200 being the gap of the belt conveyor 201.

[0113] The image reading device 200 detects the feature amounts (edges) of the conveyed loads A, B, C, etc., and detects the width of the loads based on the detection results of the feature amounts of the loads A, B, C, thereby selecting the size of the container for packaging, and it is possible to reduce waste such as using an excessively large container.

[0114] Aspects of the present invention are as follows, for example. <1> An illumination unit that irradiates light onto a subject, An imaging unit that receives the light reflected by the subject and generates an image, An edge detection unit that detects the edges of the subject, A size determination unit that determines the size of the subject according to the detection result of the edge detection unit, comprising wherein the size determination unit determines the width of the subject in the main scanning direction of the imaging unit when the upper or lower edge at both ends of the main scanning direction of the subject is not detected by the edge detection unit, and makes a determination to regard the width of the subject in the main scanning direction as a predetermined width when the upper or lower edge at both ends of the main scanning direction of the subject is detected by the edge detection unit. A reading device characterized by the above. <2> The edge detection unit detects the upper or lower edge at both ends of the main scanning direction of the subject using the image generated by the imaging unit, and the size determination unit determines the width of the subject in the main scanning direction in the image generated by the imaging unit according to whether the upper or lower edge at both ends of the main scanning direction is detected. The reading device according to <1>, characterized by the above. <3> The edge detection unit is a detection sensor arranged at both ends in the main scanning direction within the detectable range of the imaging unit in the conveyance path of the subject or the reading area of the subject, at a predetermined interval. The size determination unit determines the width of the subject in the main scanning direction according to whether the subject is detected by the detection sensor. The reading device according to <1>, characterized in that. <4> The edge detection unit detects the upper or lower edge at one end in the main scanning direction of the subject using the image generated by the imaging unit, and is a detection sensor arranged at the other end in the main scanning direction within the detectable range of the imaging unit in the conveyance path of the subject or the reading area of the subject. The size determination unit determines the width of the subject in the main scanning direction according to whether the upper or lower edge at one end in the main scanning direction is detected in the image generated by the imaging unit and whether the subject is detected by the detection sensor at the other end in the main scanning direction. The reading device according to <1>, characterized in that. <5> When the upper or lower edge at both ends in the main scanning direction of the subject or at least one of the upper or lower edges at both ends in the main scanning direction of the subject is not detected by the edge detection unit, the size determination unit determines the width of the subject in the main scanning direction. The reading device according to claim 1, characterized in that. The reading device according to any one of <1> to <4>, characterized in that. <6> The illumination unit irradiates the subject with visible light and invisible light. The imaging unit receives the visible light and invisible light reflected by the subject, and captures a visible image and an invisible image. The edge detection unit detects the upper or lower edge of the subject from at least one of the visible image and the invisible image. The reading device according to any one of <1> to <5>, characterized in that. <7> The subject is a transported object. The reading device according to any one of <1> to <6>. <8> A reading device according to any one of <1> to <7>, An image forming unit, An image processing apparatus characterized by comprising the same. <9> An illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, an edge detection unit that detects an edge of the subject, and a size determination unit that determines the size of the subject according to a detection result of the edge detection unit. A reading method in a reading device comprising: When the size determination unit does not detect upper or lower side edges at both ends in the main scanning direction of the imaging unit for the subject by the edge detection unit, a step of determining the width of the subject in the main scanning direction; When the edge detection unit detects upper or lower side edges at both ends in the main scanning direction of the imaging unit for the subject, a step of making a determination that the width of the subject in the main scanning direction is regarded as a predetermined width; A reading method characterized by including the same. <10> A computer that controls a reading device including an illumination unit that irradiates light onto a subject and an imaging unit that receives the light reflected by the subject and generates an image, An edge detection unit that detects an edge of the subject, A size determination unit that determines the size of the subject according to a detection result of the edge detection unit, A program that functions as wherein the size determination unit when the edge detection unit does not detect upper or lower side edges at both ends in the main scanning direction of the imaging unit for the subject, determines the width of the subject in the main scanning direction, when the edge detection unit detects upper or lower side edges at both ends in the main scanning direction of the imaging unit for the subject, makes a determination that the width of the subject in the main scanning direction is regarded as a predetermined width. A program characterized by the same.

Explanation of Signs

[0115] 1 Image processing apparatus 13 Lighting unit 40 Imaging unit 43 Image processing unit 52 Edge detection unit, detection sensor 101 Reading device 103 Image forming unit 431 Edge detection unit 432 Size determination unit

Prior art documents

Patent documents

[0116]

Patent Document 1

Claims

1. An illumination unit that irradiates light onto a subject; An imaging unit that receives the light reflected by the subject and generates an image; An edge detection unit that detects an edge of the subject; A size determination unit that determines the size of the subject according to the detection result of the edge detection unit; Characterized in that it comprises: The size determination unit: When the edge detection unit does not detect the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit, determines the width of the subject in the main scanning direction; When the edge detection unit detects the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit, makes a determination to regard the width of the subject in the main scanning direction as a predetermined width. A reading device characterized by the above.

2. The edge detection unit detects the upper or lower edge at both ends of the subject in the main scanning direction using the image generated by the imaging unit, The size determination unit determines the width of the subject in the main scanning direction in the image generated by the imaging unit according to whether the upper or lower edge at both ends of the main scanning direction is detected. The reading device according to Claim 1, characterized by the above.

3. The edge detection unit is a detection sensor arranged at a predetermined interval at both ends in the main scanning direction of the detectable range of the imaging unit in the conveyance path of the subject or the reading area of the subject, The size determination unit determines the width of the subject in the main scanning direction according to whether the subject is detected by the detection sensor. The reading device according to Claim 1, characterized by the above.

4. The edge detection unit detects the upper or lower edge at one end of the subject in the main scanning direction using the image generated by the imaging unit, and is a detection sensor arranged at the other end in the main scanning direction of the detectable range of the imaging unit in the conveyance path of the subject or the reading area of the subject, The size determination unit determines the width of the subject in the main scanning direction according to whether the upper or lower edge at one end of the main scanning direction is detected in the image generated by the imaging unit and whether the subject is detected by the detection sensor at the other end in the main scanning direction. The reading device according to Claim 1, characterized by the above.

5. When the size determination unit does not detect the upper or lower edge at both ends of the subject in the main scanning direction by the edge detection unit or at least one of the upper or lower edges at both ends of the subject in the main scanning direction, the width of the subject in the main scanning direction is determined. The reading device according to claim 1, characterized in that.

6. The illumination unit irradiates the subject with visible light and invisible light. The imaging unit receives the visible light and invisible light reflected by the subject and captures a visible image and an invisible image. The edge detection unit detects the upper or lower edge of the subject from at least one of the visible image and the invisible image. The reading device according to claim 1, characterized in that.

7. The subject is a transported object. The reading device according to claim 1, characterized in that.

8. A reading device according to any one of claims 1 to 7, An image forming unit, An image processing apparatus characterized by comprising.

9. A reading method in a reading device including an illumination unit that irradiates light onto a subject, an imaging unit that receives the light reflected by the subject and generates an image, an edge detection unit that detects an edge of the subject, and a size determination unit that determines the size of the subject according to the detection result of the edge detection unit, wherein the size determination unit, When the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit is not detected by the edge detection unit, a step of determining the width of the subject in the main scanning direction; When the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit is detected by the edge detection unit, a step of making a determination that the width of the subject in the main scanning direction is regarded as a predetermined width; A reading method characterized by including.

10. A computer that controls a reading device including an illumination unit that irradiates light onto a subject and an imaging unit that receives the light reflected by the subject and generates an image, An edge detection unit that detects an edge of the subject, A size determination unit that determines the size of the subject according to the detection result of the edge detection unit, A program that functions as, wherein the size determination unit, When the upper or lower edge at both ends of the subject in the main scanning direction of the imaging unit is not detected by the edge detection unit, the width of the subject in the main scanning direction is determined. A program characterized in that when the edge detection unit detects upper or lower side edges at both ends in the main scanning direction of the imaging unit for the subject, a determination is made to regard the width of the subject in the main scanning direction as a predetermined width.

Images