JP2009164808A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a harmful effect on the following processing using a detection result by erroneously detecting an original edge in an image reader. <P>SOLUTION: The image reader prescans a partial area of a platen (S210), reads a lower area of an original mounted on the platen, converts prescanned image data being the result of the reading into edge image data (S230), and extracts an edge point group corresponding to an original edge from the data. The reader also collinearly approximates the extracted edge point group and estimates an original size, an original mounted area, or the like (S235). On the other hand, the reader converts the prescanned image data into luminance data (S215), and determines whether the original is placed on a frame located at the outer edge of the platen on the basis of a luminance distribution of the edge of the platen 11a (S220). When the "existence of the original on the frame" is determined, an original size is estimated to be a maximum size at which the original size can be mounted on the platen (S245) without calculating the original size, or the like from edge image data by the above method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that generates image data representing a read image of a document placed on a document table by conveying the reading unit and causing the reading unit to read an image on a document table.

  2. Description of the Related Art Conventionally, an image reading apparatus includes a reading unit below a reading glass, and conveys the reading unit under the reading glass, and causes the reading unit to perform a reading operation when the reading unit is transported, whereby the document placed on the reading glass. An image reading apparatus that generates image data representing a read image of a document is known.

  When the image reading apparatus has a copy function, the generated image data is used for, for example, a printing process. That is, the image data representing the read image is subjected to a printing process, whereby a copy image of the read original is printed on the recording paper. As such an image reading apparatus having a copy function, a digital multifunction peripheral having a printer function, a fax (FAX) function, and the like in addition to a copy function is known.

  In addition, the image reading device grasps the area where the document is placed on the reading glass by pre-scanning, and at the time of the main scanning, the reading area is not the entire area under the reading glass but the area where the document is placed. In this reading area, a reading unit that conveys a reading unit and reads a document is known.

  In addition, an image reading apparatus that detects the size of a document based on the result of reading the document by a reading unit is known. Specifically, there is known a technique for detecting an edge of a document from a reading result and detecting a document size from the detection result (see Patent Documents 1 to 4).

The document size detection result obtained in this way is used, for example, for an automatic setting operation of a reading area at the time of a main scan and an automatic setting operation of a scaling factor at the time of copying. For example, from the detected document size and recording paper size, set the scaling ratio according to the ratio of the document size to the recording paper size, enlarge / reduce the scanned image according to the set scaling ratio, and copy the document For example, an image is printed on a recording paper at a magnification according to the paper size.
JP 2004-201240 A JP 2005-285010 A Japanese Patent Application Laid-Open No. 7-245681 JP 2001-036696 A

  However, the method of detecting the document size based on the result of reading the document by the reading unit has a problem that a ruled line in the document may be erroneously detected as the document edge.

  As a method for detecting a document edge, read image data read by a reading unit is passed through an image filter (so-called differential filter), and the read image data is converted into edge image data representing an edge image. A method for detecting the document edge, which is the outer edge of the document, is known. However, when the scanned image data is passed through an image filter, a continuous pattern of edge points is detected at the outer edge of the document. Even at the point where the ruled line exists, a pattern of continuous edge points similar to the outer edge of the document is detected.

  On the other hand, the document to be read does not necessarily have to be entirely within the readable area of the document table. For example, there is a case where a document to be read is too large, such as a newspaper, and the end of the document does not fit in the readable area.

  Therefore, if the document edge is detected from the edge image data as a result of reading even though the edge of the document is not read, the document size is erroneously detected. If such an erroneous detection of the document size occurs, for example, a variable magnification setting error occurs and the copy function does not work well.

  The present invention has been made in view of these problems, and an object of the present invention is to suppress an adverse effect on subsequent processing (such as a copying operation) using a detection result due to erroneous detection of an original edge in an image reading apparatus. And

  The present invention, which has been made to achieve the above object, conveys a reading unit under a transparent document table on which a document to be read is placed, and causes the reading unit to read an image on the document table. An image reading apparatus for generating image data representing a read image of a document placed on a table, wherein a frame surrounding the periphery of the document table is provided at the periphery of the document table. Is formed with a step with a high frame and a low document table. Further, the image reading apparatus is configured to determine whether or not a part of the document placed on the document table is on the frame as follows.

  That is, the image reading apparatus includes a state determination unit for determining whether a part of the document placed on the document table is on the frame, and the state determination unit includes the reading unit. The image data obtained as a result of reading a part of the document placed on the document table on the frame based on the luminance distribution of each pixel indicated by the image data around the boundary between the document table and the frame It is configured to determine whether or not it is in a state.

  In an image reading apparatus in which a step is provided on the periphery of the document table, when the document placed on the document table protrudes from the document table, the document rises from the document table at the edge of the document table due to the effect of the step. . Therefore, when the reading unit is caused to read an image on the platen in this state, an area corresponding to the vicinity of the end of the platen is darkened.

The image reading apparatus of the present invention uses such a phenomenon to determine whether or not a part of the document placed on the document table is on the frame.
If the image reading apparatus is configured as described above, it can be determined whether or not a part of the document placed on the document table protrudes from the document table and rests on the frame. When the state determination means determines that the image is on the frame, it is possible to detect the document edge from the image data and stop the operation for obtaining the document size or the like based on the detected document edge.

  That is, in such a case, there is a high possibility that the document size is erroneously detected even if the document edge is detected from the read image data and the document size is obtained from the document edge. If the subsequent processing is executed using the detected document size information, an error in setting the scaling factor occurs, and the subsequent processing is adversely affected, and the processing desired by the user cannot be realized. There is a high possibility of dissatisfaction. For example, the document size may be erroneously detected by detecting a ruled line in the document as a document edge. If processing such as enlargement or reduction is performed based on the erroneously detected document size, the processing result desired by the user cannot be obtained.

  Therefore, when there is a high possibility of erroneous detection, it is preferable to switch the contents of processing executed by the image reading apparatus so that no adverse effects due to erroneous detection occur. It is possible to realize switching of processing, and it is possible to suppress adverse effects on subsequent processing using the detection result due to erroneous detection of the document edge.

  More specifically, the state determination means determines the length of the black area whose luminance spreading from the boundary between the document table and the frame is equal to or less than the threshold value from the luminance information of each pixel indicated by the image data around the boundary between the document table and the frame The configuration is such that when the length of the black area is equal to or longer than a predetermined distance, it is determined that a part of the document placed on the document table is on the frame. (Claim 2).

In addition, in order to detect with high sensitivity that the original is protruding from the original table, it is preferable to specifically configure the image reading apparatus as follows.
That is, a specific edge of the document table is defined as a document abutting position where the document is to be abutted, and “a document abutting position is a portion of a frame that exists symmetrically across the document table”. It is preferable to configure the frame such that the height of the step from the surface of the document table is higher than the height of the step from the surface of the document table formed by the “part of the frame corresponding to the document abutting position” ( Claim 3).

  In the image reading apparatus in which the document abutting position is set in this way, when a large-size document is placed, the document runs on the frame at a portion of the frame located on the opposite side to the document abutting position. become. Therefore, if the part of the frame on which the document is carried is set higher than the other parts as in the present invention, the document is likely to float around the part. Therefore, according to the present invention, it is possible to detect the running of the document with high sensitivity from the luminance distribution of the image data.

  In addition, the above-described image reading apparatus notifies the user of the fact when a part of the document placed on the document table is on the frame based on the determination result of the state determination unit. It is possible to adopt a configuration provided with means (claim 4).

  By providing the notification means in the image reading apparatus in this way, it is possible to notify the user that there is a possibility that a desired result may not be obtained. For example, it is possible to prompt the user to manually input the document size. . Therefore, according to the present invention, a highly convenient image reading apparatus can be provided to the user.

  In addition, the above-described image reading apparatus may be configured as follows. That is, the image reading apparatus detects the edge of the document placed on the document table based on the image data that is the reading result of the reading unit, and based on this detection result, the size of the document placed on the document table. The document estimation unit is configured to estimate the position of the document. When the state determination unit determines that a part of the document is on the frame, the document estimation unit is placed on the document table regardless of the edge detection result. It is preferable that the size of the original document is estimated to be the maximum size that can be placed on the document table.

  When the document is placed on the protruding frame from the document table, it is natural that the document is likely to be larger than the size of the document table. Therefore, when it is determined by the state determination means that a part of the document is on the frame, the subsequent process can be appropriately executed by estimating the document size as the maximum size.

  For example, consider an image reading apparatus that estimates a document size by pre-scanning and determines a reading area in main scanning based on the estimation result. Further, in such an image reading apparatus, although a document having a size larger than that of the document table is placed on the document table, the document edge is erroneously detected due to the influence of the ruled line of the document. Therefore, when the document size is estimated based on the document edge, a situation is considered in which the document size is smaller than the maximum size that can be read by the image reading apparatus.

  In such a situation, if the reading area is set based on the document size estimated from the document edge, the document placed on the document table can be read during the main scan by making the best use of the capabilities of the image reading device. However, if the document estimation unit is configured as described above, when a large document is placed on the document table, the maximum capacity of the image reading device can be utilized to maximize the document. A wide range can be read.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1A is a block diagram illustrating the configuration of the digital multifunction peripheral 1 according to the present embodiment. As shown in FIG. 1A, the digital multifunction peripheral 1 of this embodiment includes an image reading unit 10, a reading control unit 20, a printing unit 30, a printing control unit 40, a display operation unit 50, a communication unit 60, a CPU 70, A RAM 80 and a flash memory 90 are provided, and various processes are executed by the CPU 70 based on a program recorded in the flash memory 90 to control the entire apparatus.

  Specifically, the image reading unit 10 is configured as shown in FIGS. FIGS. 1B and 1C are explanatory diagrams showing the configuration of the image reading unit 10. The image reading unit 10 is configured such that a transparent plate-shaped reading glass 11 on which a document P to be read is placed is supported by a housing 13, and the reading is performed below the reading glass 11 in the housing 13. A reading unit 15 that optically reads an image reflected on the glass 11 in the main scanning direction, a conveying mechanism 16 that conveys the reading unit 15 in the sub-scanning direction, and a motor 17 that drives the conveying mechanism 16 are provided.

  The image reading unit 10 drives the transport mechanism 16 by the rotational force of the motor 17 in accordance with a control signal input from the reading control unit 20, thereby causing the reading unit 15 to move under the reading glass 11 in the sub-scanning direction (FIG. 1 ( b) While being conveyed in the direction of the dotted arrow shown in (c), the reading unit 15 is caused to perform a reading operation during conveyance.

  Note that the reading unit 15 is controlled by the reading control unit 20 and, as it moves in the sub-scanning direction, reads an image shown on the reading glass 11 line by line and outputs a line image signal representing the read image. (CIS). The line image signal output from the reading unit 15 is converted into digital data (line image data) by an A / D converter (not shown) and input to the reading control unit 20.

  The image reading unit 10 is provided with a lid (not shown) that can cover the reading glass 11 so as to be openable and closable similarly to a known scanner. When the reading operation by the reading unit 15 is performed, a manual operation by the user is performed. By the operation, the lid is closed so as to be placed on the document placed on the reading glass 11. A white member is provided on the inner side of the lid facing the reading glass 11 so that a black shadow does not appear in the outer area of the document in the image data that is the reading result of the reading unit 15 (details will be described later). .

  On the other hand, the reading control unit 20 executes a reading control process in accordance with an instruction from the CPU 70, and controls the movement of the reading unit 15 in the sub-scanning direction and controls the reading operation of the reading unit 15 in the reading control process. To do.

  With this control, the reading control unit 20 causes the reading unit 15 to read an image reflected in the reading area of the reading glass 11 designated by the CPU 70 while conveying the reading unit 15 under the reading glass 11 in the sub-scanning direction. Image data representing an image shown in the reading area of the reading glass is recorded in the RAM 80. By such an operation, image data representing a read image of the document P placed in the reading area of the reading glass 11 is recorded in the RAM 80.

  The reading control unit 20 temporarily stores each line image data input from the image reading unit 10 in a built-in buffer, performs image processing such as shading correction on each line image data, and then executes each line image data. Image data is recorded in the RAM 80.

  In addition, the printing unit 30 conveys a recording sheet placed on a tray (not shown) to a recording position in accordance with a control signal input from the printing control unit 40, and is well-known such as an ink jet method or a laser printer method. In this recording method, an image corresponding to the control signal is formed on the recording paper.

  The print control unit 40 controls the printing unit 30 to form an image on recording paper. In accordance with a command from the CPU 70, an image based on the print target data designated by the CPU 70 is transmitted through the printing unit 30. Print on recording paper.

  The communication unit 60 includes a group of interfaces for communicating with an external device, and includes a USB interface, a LAN interface, a FAX modem, and the like. That is, the multi-function device 1 is configured to be capable of performing FAX communication with an external FAX device through a FAX modem provided in the communication unit 60, and configured to be capable of communicating with an external personal computer through a USB interface or a LAN interface.

  In addition, the display operation unit 50 includes a liquid crystal display (not shown) for displaying information and various operation keys, and is controlled by the CPU 70 to display information for the user on the liquid crystal display. The command from the user input through is input to the CPU 70.

  Further, the CPU 70 realizes a copy function, a FAX function, a scanner function, a printer function, and the like according to a command input through an operation key or a command input from an external personal computer or the like through the communication unit 60 by executing a program. To do.

  For example, when a copy command is input from the user through an operation key provided on the display operation unit 50, the CPU 70 executes a copy control process (see FIG. 3) to control each unit in the apparatus, and on the reading glass 11. The read image of the placed document P is printed on a recording sheet. More specifically, the size of the document P placed on the reading glass 11 is estimated based on the reading result by the reading unit 15, and the scaling ratio is set from the estimated document size and the recording paper size, and the document P The read image is enlarged or reduced to a size suitable for the recording paper size, and this is printed on the recording paper through the printing unit 30 (automatic scaling copying process).

The contents of the copy control process will be specifically described below. Prior to that, the characteristics of the image reading unit 10 of this embodiment will be described with reference to FIG.
2A and 2B are explanatory views showing the configuration around the reading glass 11 of the image reading unit 10. In particular, FIG. 2A is a plan view around the reading glass 11, and FIG. It is AA 'sectional drawing of the surroundings of the reading glass 11 along the AA' dashed-dotted line shown in FIG.

  In the multifunction device 1, a reading glass 11 that is a rectangular glass plate is provided so as to close the opening portion in the opening portion of the rectangular housing 13 whose one surface is opened. The periphery of the reading glass 11 is supported by a housing 13.

  The reading glass 11 is provided slightly below the upper surface of the housing 13 from the upper surface of the housing 13, and an area 11 a of the reading glass 11 exposed from the housing 13 (hereinafter, referred to as “original table”). A step is formed at the boundary BD between the casing 13 and the casing 13 so that the original P can be abutted (hereinafter referred to as a portion 13a above the reading glass 11 of the casing 13 (the portion forming the step)). Expressed as “frame”.)

  In other words, in the present embodiment, a frame 13a surrounding the periphery of the document table 11a is provided at the periphery of the document table 11a, and the frame 13a is positioned at the boundary BD between the document table 11a and the frame 13a by the frame 13a. A step is formed in which the height of the document platen 11a is low and the level of the document table 11a is low.

  In the image reading unit 10, a mark MK is instructed in the lower left part of the frame 13a to instruct the corner of the document P to abut. In this embodiment, the corner of the document table 11a to which the mark MK is attached is defined as “lower left corner”, and the corner of the document table 11a located at a point farther in the main scanning direction than the lower left corner is defined. The “lower right corner” is defined, and the corner of the document table 11a located at a point away from the lower left corner in the sub-scanning direction is defined as the “upper left corner”.

  That is, in the multi function device 1, the lower left corner of the document table 11a (in other words, the lower left corner inside the frame 13a) is determined as the position where the corner of the document P should be aligned. In other words, the left edge and the lower edge of the document table 11a extending from the lower left corner of the document table 11a are defined as the edges to be aligned with the document.

  The multi-function device 1 assumes that the user is placing the original P so that the user generally abuts the step between the left and lower edges of the original table 11a in accordance with the mark MK. Estimate the size.

  In addition, in the present embodiment, the height h ′ of the right side 13a (R) of the frame 13a in contact with the right edge of the document table 11a from the surface of the document table 11a is the left edge of the document table 11a against which the document is abutted. Different values are set for the height h from the surface of the document table 11a of the lower side 13a (D) of the frame 13a in contact with the left side 13a (L) of the frame 13a in contact and the lower edge of the document table 11a. Hereinafter, the right side 13a (R) of the frame 13a is designated as the right frame 13a (R), the left side 13a (L) of the frame 13a is designated as the left frame 13a (L), the upper side 13a (U) of the frame 13a is designated as the upper frame 13a ( U), the lower side 13a (D) of the frame 13a is referred to as a lower frame 13a (D).

  More specifically, as shown in FIG. 2B, the height h ′ of the step formed by the right frame 13a (R) from the surface of the document table 11a is located symmetrically with respect to the document table 11a. The height of the step formed by the left frame 13a (L) and the lower frame 13a (D) is higher than the height h from the surface of the document table 11a (h ′> h).

  As described above, the step difference between the right frame 13a (R) located on the opposite side of the document table 11a from the left frame 13a (L) against which the document is abutted is set higher than the document table 11a. In this embodiment, it is detected that a document having a size larger than the document table 11a is placed by detecting whether or not the document has been placed on the frame 13a opposite to the document abutting position. This is because the multifunction device 1 is configured.

  When the manuscript rides on the frame 13a, the manuscript floats from the manuscript table 11a around the place where the manuscript rides, and the read image at that point becomes black. In the present embodiment, such a phenomenon is detected by analyzing image data that is a reading result of the reading unit 15 to determine whether or not the document is loaded on the right frame 13a (R) (details will be described later). ), Such a phenomenon becomes more prominent as the right frame 13a (R) is raised. In this embodiment, for this reason, the right frame 13a (R) is set higher than the left frame 13a (L) and the lower frame 13a (D).

  Further, in the image reading unit 10 of the present embodiment, a rectangular area R0 that is slightly narrower than the entire area of the rectangular original table 11a is obtained due to the relationship between the line width of the reading unit 15 and the size of the original table 11a. The reading unit 15 defines a readable area R0 where the original can be read. Specifically, the readable region R0 has an outer periphery at a position separated by a minute amount (3 mm in this embodiment) from the boundary BD between the frame 13a and the reading glass 11, as indicated by a dotted line in FIGS. It is an area with

  In addition, in the multifunction machine 1 of this embodiment, the lower left corner of the readable area R0 corresponding to the inner lower left corner of the frame 13a with the mark MK is the origin, the main scanning direction is the X axis, and the sub scanning direction is An XY coordinate system (see FIG. 2C) with the Y axis is introduced, and the CPU 70 executes the copy control process shown in FIG. 3 using this XY coordinate system.

  Next, a copy control process executed by the CPU 70 will be described. FIG. 3 is a flowchart showing a copy control process executed by the CPU 70 when a copy command is input through the operation keys.

  When the copy control process is started, the CPU 70 determines whether or not the copy command input through the operation key is an “automatic scaling / tilt correction” copy command (S110), and copies the “automatic scaling / tilt correction”. If it is determined that it is a command (Yes in S110), the automatic zoom copying process shown in FIG. 4 is executed in S120. Thereafter, the copy control process ends.

  On the other hand, if it is determined that the copy command input through the operation key is a copy command other than the “automatic scaling / tilt correction” copy command (for example, a normal copy command without an automatic scaling or tilt correction instruction). In step S130, the CPU 70 executes processing corresponding to the input copy command, and then ends the copy control processing.

Next, the automatic scaling copying process executed by the CPU 70 in S120 will be described. FIG. 4 is a flowchart showing the automatic scaling copying process executed by the CPU 70.
When the CPU 70 starts the automatic scaling copying process in S120, first, the document reading start position is set to the lower end (Y = 0) of the readable area R0, and the document reading end position is predetermined in the design stage. By setting a position (Y = YPRE) that is a predetermined distance away from the lower end of the readable area R0, a part of the readable area R0 corresponding to the area from the original reading start position to the original reading end position is read. An area (in other words, a pre-scan area) is set, and the image reading unit 10 is caused to execute a pre-scan operation on the reading area through the reading control unit 20 (S210: tip portion pre-scanning process).

  That is, in S210, the pre-scanning operation is not performed on the entire readable area R0 by the image reading unit 10, but from the lower end of the readable area R0 to a point a predetermined distance away from the readable area R0 (this embodiment). In the example, the image reading unit 10 is caused to perform a pre-scan operation for a point 30 mm away from the lower end of the readable region R0. As a result, the CPU 70 acquires, as a pre-scan result, image data representing the read result of a partial area of the readable area R0 from the image reading unit 10.

  As a pre-scan operation, the image reading unit 10 conveys the reading unit 15 in the sub-scanning direction at a speed corresponding to the pre-scan resolution from the end of the set reading area to the end of the reading area. The image is read by the reading unit 15 and, as a prescan result, low resolution image data (hereinafter referred to as “prescan image data”) is recorded in the RAM 80 through the read control unit 20.

  When the processing in S210 is completed in this manner, the CPU 70 then converts the RGB value of each pixel indicated by the prescan image data recorded in the RAM 80 into a luminance value Z according to a predetermined calculation formula. The prescan image data is converted into luminance data representing the luminance value of each pixel (S215). As is well known, conversion from RGB values to luminance values Z can be performed according to the calculation formula Z = α · R + β · G + γ · B using coefficients α, β, and γ.

  When this process is completed, the CPU 70 proceeds to S220, and executes the riding determination process shown in FIG. 5 based on the generated luminance data. FIG. 5 is a flowchart showing the ride determination process executed by the CPU 70.

  When the boarding determination process is started, the CPU 70 first sets the sub-scanning direction inspection position Ye to the inspection start position YINI predetermined in the design stage in S310 (Ye = YINI). Note that the inspection start position YINI is set to a value not less than 0 and less than YPRE because the pre-scan is executed in the region from Y = 0 to Y = YPRE.

  When the process in S310 is completed, the CPU 70 proceeds to S321 and sets the main scanning direction inspection position Xe to the X coordinate of the right end of the readable area R0 (in other words, the right end of the prescan area) ( Xe = XMAX).

  When this process is finished, the CPU 70 refers to the luminance data, and corresponds to the inspection position (X, Y) = (Xe, Ye) determined by the main scanning direction inspection position Xe and the sub scanning direction inspection position Ye. A luminance value Z of the pixel is obtained, and it is determined whether or not the luminance value Z of the pixel corresponding to the inspection position (Xe, Ye) exceeds a predetermined threshold value Zth (S323). That is, it is determined whether Z> Zth.

  When it is determined that the luminance value Z is equal to or less than the threshold value Zth (that is, Z ≦ Zth) (No in S323), the CPU 70 proceeds to S325 and sets the main scanning direction inspection position Xe in the minus direction by one pixel. After updating to the value shifted to (ie, after updating to Xe ← Xe−1), the process proceeds to S327.

  In S327, it is determined whether or not the updated main scanning direction inspection position Xe is the left end of the readable area R0 (in other words, the left end of the prescan area). That is, it is determined whether Xe = 0. When it is determined that the updated main scanning direction inspection position Xe is the left end of the readable area R0 (Yes in S327), the process proceeds to S329.

  On the other hand, if Xe> 0 and the updated main scanning direction inspection position Xe is determined not to be the left end of the readable area R0 (No in 327), the CPU 70 proceeds to S323 and updates the updated inspection position (X , Y) = (Xe, Ye), it is determined whether or not the luminance value Z of the pixel corresponding to this inspection position exceeds the threshold value Zth.

  If it is determined that the luminance value Z of the pixel corresponding to the inspection position is equal to or smaller than the threshold value Zth (No in S323), the process proceeds to S325, and the luminance value Z of the pixel corresponding to the inspection position exceeds the threshold value Zth. If it is determined (Yes in S323), the process proceeds to S329.

  In S329, the X-axis direction length L from the right end of the readable area R0 to the currently set main scanning direction inspection position Xe is set as the black area length L (Y = Ye) at the point where the coordinate Y = Ye. calculate.

That is, the black area length L (Y = Ye) at the point of the coordinate Y = Ye is calculated according to the formula L = XMAX−Xe.
When the process in S329 is completed, the CPU 70 proceeds to S330 and updates the sub-scanning direction inspection position Ye to a position moved by one pixel in the Y axis plus direction (Ye ← Ye + 1). Thereafter, it is determined whether or not the sub-scanning direction inspection position Ye exceeds the inspection end position YFIN determined in the design stage (S340). Note that the inspection end position YFIN is set to a value between 0 and YPRE by the designer at the design stage, like the inspection start position YINI. However, as a matter of course, the inspection end position YFIN is determined at a point shifted in the Y axis plus direction from the inspection start position YINI (YFIN> YINI).

  If it is determined that the sub-scanning direction inspection position Ye does not exceed the inspection end position YFIN (ie, if it is determined that Ye ≦ YFIN), the CPU 70 proceeds to S321 and executes subsequent processing. By repeating such an operation, the CPU 70 calculates the black region length L (Y) from the right end of the readable region R0 as the base point at each coordinate Y from the inspection start position YINI to the inspection end position YFIN by the above-described method. To do.

  If the CPU 70 determines that the sub-scanning direction inspection position Ye exceeds the inspection end position YFIN (Yes in S340), the CPU 70 proceeds to S350 and calculates each coordinate Y in the range of YINI ≦ Y ≦ YFIN calculated in S329. The average value AVE (L) of the black area length L (Y) is calculated using the value of the black area length L (Y).

  When the process in S350 is completed, the CPU 70 determines whether or not the average value AVE (L) is equal to or greater than a predetermined threshold Lth (S360). If it is determined that the average value AVE (L) is equal to or greater than the threshold value Lth (Yes in S360), it is determined that the document is being carried on the right frame 13a (R) (S370). On the other hand, if it is determined that the average value AVE (L) is less than the threshold value Lth (No in S360), it is determined that the document is not mounted on the right frame 13a (R), and “no boarding” determination is made (SS380).

In this way, when the process of S370 or S380 is completed, the CPU 70 ends the ride-up determination process and proceeds to S225.
FIG. 6A is an explanatory diagram showing the distribution of luminance at the end of the document table 11a when no document is placed on the frame 13a, and FIG. 6B is a diagram where the document is placed on the frame 13a. FIG. 6 is an explanatory diagram showing the distribution of luminance at the end of the document table 11a when the document is present.

  In this embodiment, the white member provided inside the openable / closable lid provided in the image reading unit 10 is configured by a member that is more flexible than paper and can be easily deformed. When the pre-scan operation is performed in a closed state, and no document is running on the frame 13a, the white member replaces the document in the area where the document is not placed on the document table 11a. In almost the entire area, the surface of the document table 11a is contacted to cover the surface of the document table 11a. In addition, the dotted line shown to the upper figure of Fig.6 (a) shows arrangement | positioning of the white member (lid inner surface) at this time.

For this reason, when the document does not run on the frame 13a, the brightness value Z is higher than the above-described threshold value Zth up to the end of the readable area R0.
On the other hand, when a document is placed on the frame 13a, a step is provided between the frame 13a and the document table 11a, and the white member is formed of a member that is more flexible than the paper. In the region between the frame 13a and the document table 11a sandwiching the end of the readable region R0, the document is lifted from the document table 11a. In this region, the surface of the document table 11a is composed of the document and the white member. It will be in the state which is not coat | covered by any.

  6B shows the state of the surface of the original platen 11a in which the original has been lifted from the original platen 11a together with the white member constituting the inner surface of the lid by riding the original on the frame 13a. . In the upper diagram of FIG. 6B, the dotted line indicates the arrangement of the white member (the inner surface of the lid).

  As is well known, in reading using a contact image sensor, when a document or the like is not in contact with the surface of the document table 11a and the surface of the document table 11a is not covered, the read image in that region is compared with other regions. It becomes black. In other words, in a region where the document is lifted from the document table 11a, a pixel region having a luminance value Z lower than the threshold value Zth is expanded.

  In this embodiment, for this reason, the length of the black region L (Y) from the right frame 13a (R) is calculated in the region of Y = YINI to Y = YFIN, and this average value AVE (L) Is greater than or equal to the threshold value Lth, it is determined that the document is on the right frame 13a (R).

  When the boarding determination process is terminated based on this principle and the process proceeds to S225, the CPU 70 determines whether or not the “boarding” determination is made in the boarding determination process executed in the immediately preceding S220. Then, if it is determined that the “ride on” determination is not made and the “no ride” determination is made (No in S225), the process proceeds to S230.

  In S230, edge detection processing is performed on the luminance data corresponding to the pre-scan image data recorded in the RAM 80, and edge image data corresponding to the image data is generated. That is, in S230, the luminance data is passed through an edge detection image filter (a well-known differential filter), and edge image data representing an edge image corresponding to the image data is generated.

  When the processing in S230 is completed, the CPU 70 proceeds to S235, sets the generated edge image data as inspection target data, and executes the document estimation processing shown in FIG. Although details will be described later, in this document estimation process, the inspection target data (edge image data obtained in S230) is analyzed, and the size (vertical width and horizontal width) of the document placed on the document table 11a, and The document inclination angle θ and the document placement area on the document table 11a are estimated.

  Specifically, under the assumption that the document placed on the document table 11a has a square shape, the edge of the document placed on the document table 11a is detected in the inspection target data, and the detection result is used. The lower left corner position and the lower right corner position of the document are estimated, and the document is placed on the document table 11a under the assumption that the document placed on the document table 11a is a standard sheet based on the estimated corner position information. The size of the original, the inclination angle θ of the original, and the original placement area on the original table 11a are estimated. However, here, the angle formed by the lower side of the document with respect to the X axis is the document inclination angle θ (see FIG. 10).

  When the processing in S235 is completed, the CPU 70 causes the printing unit 30 to execute a paper feeding operation through the print control unit 40 (S250) and detects the size of the recording paper that is the target of the paper feeding operation (S250). S255). The size of the recording paper can be detected by a well-known method using, for example, a sensor provided in the recording paper conveyance path.

  When this process is finished, the CPU 70 proceeds to S261, and sets a scaling factor according to a predetermined calculation formula based on the document size estimated in S235 and the recording paper size detected in S255. Specifically, the scaling factor is set to a magnification corresponding to the ratio between the document size and the recording paper size (for example, recording paper short side length ÷ original short side length), and the copy of the original is performed in the subsequent processing. The image is enlarged (or reduced if the magnification is less than 1) at a magnification corresponding to the ratio of the recording paper size to the document size and printed on the recording paper.

  When this process is completed, the CPU 70 sets the inclination correction amount of the image data from the original inclination angle θ estimated in S235 (S263). Specifically, the tilt correction amount is set so that the copy image of the document is printed straight on the recording paper without tilting. However, when the estimated document inclination angle θ is a minute amount (in the present embodiment, −0.5 degrees ≦ θ ≦ 0.5 degrees), the inclination correction amount is set to zero in consideration of errors. To do.

  When the processing in S263 is completed, the CPU 70 sets the document reading start position and the document reading end position based on the document placement area information estimated in S235, and the document reading start position and the document reading end. The reading area determined by the position is made to correspond to the document placement area on the document table 11a (S265).

  Specifically, the document reading start position is set to a position corresponding to the end point of the document located on the lowermost side in the sub-scanning direction so that the reading unit 15 can read the entire document placement area. The document reading end position is set to a position corresponding to the end point of the document located on the uppermost side in the sub-scanning direction, and the reading area is made to correspond to the document placement area on the document table 11a. When this process is finished, the process proceeds to S270.

  On the other hand, if it is determined in S225 that the determination “Yes” is made, the CPU 70 proceeds to S241 and displays a message indicating that the document is on the frame 13a on a display provided in the display operation unit 50. Then, the user is notified of the start of the document. In this case, a message for inquiring whether or not to continue the subsequent process is displayed on a display provided in the display operation unit 50, thereby prompting the user to input an answer to the inquiry through the operation key.

  When this process is completed, the CPU 70 proceeds to S243 and waits until an answer to the inquiry is input through the operation key. When an answer is input, it is determined whether or not a processing continuation instruction is input from the user based on the type of the input answer. Specifically, in S243, when an answer “continuation required” of the subsequent process is input as the above-mentioned answer, it is determined that a process continuation instruction is input from the user (Yes in S243). On the other hand, if an answer “continuation unnecessary” of the subsequent process is input as the answer, it is determined that a process continuation instruction has not been input from the user (No in S243).

  If it is determined that the process continuation instruction has not been input from the user (No in S243), the CPU 70 terminates the automatic scaling copying process, thereby invalidating the copy command that led to the execution of the process of S243. .

  On the other hand, if it is determined that a processing continuation instruction has been input from the user (Yes in S243), the CPU 70 proceeds to S245 and determines the size (vertical width and horizontal width) of the document placed on the document table 11a according to the present embodiment. It is estimated that the maximum size of the document that can be placed on the document table 11a in the multi-function device 1. That is, it is estimated that the document size is the same size as the readable area R0. In addition, the CPU 70 estimates that the placement area of the document placed on the document table 11a is the entire readable area R0, and that the inclination angle θ of the document is zero (θ = 0). Estimate (S247).

  When the processing in S247 is completed, the CPU 70 proceeds to S250, causes the printing unit 30 to execute a paper feeding operation through the print control unit 40, and detects the size of the recording paper that is the target of the paper feeding operation. (S255). After this processing, the process proceeds to S261, and the scaling ratio is set by the above-described method based on the document size estimated in S245 and the recording paper size detected in S255.

  When this processing is completed, the CPU 70 sets the inclination correction amount of the image data from the document inclination angle θ estimated in S247 (S263), and further, information on the document placement area estimated in S245. Based on the above, the reading area at the time of the main scan (when executing S270) is made to correspond to the document placement area on the document table 11a (S265). Specifically, in S265 after determining Yes in S225, the document reading start position is set to the lower end (Y = 0) of the readable area R0, and the document reading end position is set to the upper end (Y = YMAX), and the entire readable area R0 is set as a reading area. When this process is finished, the process proceeds to S270.

  In step S <b> 270, the CPU 70 controls the image reading unit 10 through the reading control unit 20 to convey the reading unit 15 to the image reading unit 10 from the document reading start position to the document reading end position in the sub-scanning direction. In addition, during the conveyance, the reading unit 15 performs a reading operation for each line, causes the reading unit 15 to read the image of the set reading area, and image data representing a reading result of the reading area is It is recorded in the RAM 80 (S270).

  When this process is completed, the CPU 70 enlarges or reduces the image data representing the read result recorded in the RAM 80 at a preset magnification, and performs a rotation process for a preset inclination correction amount. Then, the image data representing the read result is converted into image data for printing, and the converted image data is set as print target data (S280). However, if the tilt correction amount is set to zero, the rotation process is not executed in S280.

  When the process in S280 is completed, the CPU 70 executes a print process for the print target data (S290). That is, the printing unit 30 causes the printing unit 30 to print an image based on the print target data on the fed recording paper. Thereafter, the copy control process ends.

  In this way, in the automatic scaling copying process, the document size and the like are estimated based on the prescan result of the partial area in the readable area R0, and the read area at the time of the main scan (when executing S270) is determined based on the result. At the same time, a scaling factor and an inclination correction amount are determined. However, in this embodiment, when it is detected that the document has entered the frame 13a, the document size is estimated as the maximum size, based on the prescan result, and the document placement area is estimated as the entire readable area R0. The reading area at the time of the main scan is determined over the entire readable area R0.

  Note that the reason why the document size is estimated to be the maximum size without using the pre-scan result when the document is loaded on the frame 13a is detected in the document estimation process in S235 in this embodiment. This is because the edge of the document is detected from the prescan result, and the size of the document placed on the document table 11a is estimated based on the detection result.

  That is, when a document having a size exceeding the maximum size that can be placed on the document table 11a is placed on the document table 11a, the process of S235 is executed to obtain the document size and the like. There is a possibility that the edge of the document is erroneously detected due to the influence of the ruled line described in FIG. For this reason, in the present embodiment, when the rising of the document frame 13a is detected, the process related to document estimation is switched.

Hereinafter, the document estimation process executed by the CPU 70 in S235 will be described with reference to FIG. FIG. 7 is a flowchart showing document estimation processing executed by CPU 70.
When the document estimation process is started, the CPU 70 first sets the variable S to YPRE which is the Y coordinate of the upper end of the pre-scan area (S = YPRE), thereby setting the inspection range in the Y-axis direction to Y = 0. To Y = S = YPRE (S410). When this process ends, the process proceeds to S420, and a right edge detection process is executed. FIG. 8 is a flowchart showing the right edge detection process executed by the CPU 70.

  When the right edge detection process is started, the CPU 70 first sets the sub-scanning direction inspection position Ye to the lower end Y coordinate of the readable area R0 (Ye = 0) in S510, and the main scanning direction inspection position in S515. Xe is set to the right end X coordinate of the readable region R0 (Xe = XMAX). In S515, the variable C is initialized to zero (C = 0). Thereafter, it is determined whether or not the sub-scanning direction inspection position Ye exceeds the inspection range (S520). Specifically, it is determined whether or not Ye> S.

  If it is determined that the sub-scanning direction inspection position Ye does not exceed the inspection range (No in S520), the CPU 70 determines the inspection position (X, Y) = determined by the main scanning direction inspection position Xe and the sub-scanning direction inspection position Ye = It is determined whether or not the inspection position (Xe, Ye) is an edge point by referring to the pixel value of the inspection target data corresponding to (Xe, Ye) (S525). FIG. 9 is an explanatory diagram showing the configuration of the edge image data, and further showing the locus of the edge point tracked by the right edge detection process. In the example illustrated in FIG. 9, a point with a pixel value “1” corresponds to an edge point.

  If the CPU 70 determines that the inspection position (Xe, Ye) is not an edge point (No in S525), the CPU 70 proceeds to S540 and moves the main scanning direction inspection position Xe by one pixel in the X-axis minus direction. (Xe ← Xe−1), and it is determined whether or not the updated main scanning direction inspection position Xe protrudes from the left end of the readable area R0. Specifically, it is determined whether or not Xe <0 (S543).

  If the CPU 70 determines that the main scanning direction inspection position Xe does not protrude from the left end of the readable region R0 (No in S543), the CPU 70 proceeds to S520, and the sub scanning direction inspection position Ye exceeds the inspection range. If it is determined whether or not (Ye> S) and the sub-scanning direction inspection position Ye does not exceed the inspection range (No in S520), the process proceeds to S525 and the sub-scanning direction inspection position Ye is determined. If it is determined that the value exceeds the inspection range (Yes in S520), the process proceeds to S590.

  On the other hand, in S543, when it is determined that the main scanning direction inspection position Xe protrudes from the left end of the readable area R0 (when it is determined that Xe <0), the CPU 70 proceeds to S547, and the main scanning direction inspection position Xe. Is set to the right end (XMAX) of the readable region R0 (Xe = XMAX), and the sub-scanning direction inspection position Ye is updated to a value obtained by adding 8 to the current value Ye (Ye ← Ye + 8). That is, the sub-scanning direction inspection position Ye is set to a position advanced by 8 pixels in the Y-axis direction. Thereafter, the process proceeds to S520, and the above-described processing is executed.

  If the CPU 70 determines that the inspection position (Xe, Ye) is an edge point (Yes in S525), the CPU 70 proceeds to S530, and the coordinates of the current inspection position (Xe, Ye) are set in the variable (X0, Y0). The value is set (X0 ← Xe, Y0 ← Ye). Further, the variable Y1 is updated to a coordinate value Y1 (= Y0 + 8) advanced by 8 pixels from the coordinate Y = Y0 in the Y-axis direction (S533).

  Thereafter, it is determined whether at least one of the point of coordinates (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (S537). If none of the point of (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (No in S537), the process proceeds to S540. The scanning direction inspection position Xe is updated to a position moved by one pixel in the X axis minus direction (Xe ← Xe−1).

  On the other hand, when it is determined that at least one of the point of coordinates (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (Yes in S537), The process proceeds to S550, where it is determined that the point of coordinates (X0, Y0) is a continuous edge point, and this coordinate (X0, Y0) is temporarily stored as coordinate data of the continuous edge point. .

  When this processing is finished, the CPU 70 proceeds to S560, and at the point of the coordinates (X0-1, Y1), the coordinates (X0, Y1), and the coordinates (X0 + 1, Y1) at the edge point. One of the points is selected according to a predetermined priority.

  Specifically, in the right edge detection process, higher priority is set for coordinates closer to the right end side of the readable area R0. That is, the point of the coordinate (X0 + 1, Y1) close to the right end side of the readable area R0 is set to the priority “high”, the point of the coordinate (X0, Y1) is set to the priority “medium”, and the coordinate (X0− 1, Y1) is set to the priority “small”.

  The priority is set in this way because nothing exists on the platen 11a on the right side from the right end of the document, and there should be no edge point, and an edge point close to the right end side of the readable area R0. This is because there is a higher possibility that the edge point corresponds to the right edge of the document.

  That is, in S560, according to the above priority, the point of the coordinate (X0-1, Y1), the point of the coordinate (X0, Y1), and the point of the coordinate (X0 + 1, Y1) are points that are edge points. To select the point with the highest priority. Then, the variable X0 is updated to the X coordinate of the selected point, and the variable Y0 is updated to the Y coordinate of the selected point. Thereafter, the variable C is updated to a value obtained by adding 1 (S563).

  When this process is finished, the CPU 70 determines whether or not the value of the updated variable C is C = 8. If the CPU 70 determines that C = 8 is not satisfied (No in S567), the process proceeds to S533. The variable Y1 is updated to the Y coordinate of the point advanced by 8 pixels in the Y-axis direction from the coordinate Y = Y0 (Y1 = Y0 + 8). Thereafter, the processing after S537 is executed.

  By executing such processing, the CPU 70 checks whether the edge points are continuous in the Y-axis direction every 8 pixels in the Y-axis direction, as shown in FIG. If it is determined that C = 8 (Yes in S567), the coordinate data of a total of eight points determined as the continuous edge points in the process of S550 that has been repeated eight times is stored in the RAM 80 as the original right edge data. (S570).

  When this process is finished, the CPU 70 proceeds to S580, determines whether or not the sub-scanning direction inspection position Ye exceeds the inspection range (whether or not Ye> S), and performs the sub-scanning direction inspection. If it is determined that the position Ye does not exceed the inspection range (No in S580), the sub-scanning direction inspection position Ye is updated to a position advanced by 64 pixels (S585), and the process proceeds to S515.

  In this way, the CPU 70 repeatedly detects eight consecutive edge points as one set. When the sub-scanning direction detection position Ye exceeds the inspection range (Yes in S520 or Yes in S580), the process proceeds to S590, and the right edge (original document) is selected from the coordinate data group stored as the original right edge data in S570. The edge data representing the right edge of the document) is deleted as a low-accuracy coordinate data group, and the document right edge data is determined.

  Specifically, as shown in FIG. 10, among the coordinate data groups stored as the right edge data of the document, it is clearly continuously located at a position greatly shifted to the inner region of the document with respect to the coordinate data group having continuity. The inconsistent coordinate data group is removed from the document right edge data, and the document right edge data is determined. Thereafter, the right edge detection process ends. However, since the process of S590 is a process for improving the document edge detection accuracy, the right edge detection process may be configured not to execute the process of S590.

  In this way, when the right edge detection process is completed, the CPU 70 proceeds to S430, and determines whether or not the right edge detection has failed in the immediately preceding right edge detection process. Specifically, when there is no coordinate data registered as document right edge data in the immediately preceding right edge detection process, it is determined that detection of the right edge has failed, and there is coordinate data registered as document right edge data It is determined that the right edge has been successfully detected.

  However, exceptionally, when the coordinate data registered as the document right edge data is in the vicinity of the left end (Y = 0) of the readable region R0, the coordinate data of the left edge (the edge point representing the left end of the document) is It may be determined that the detection of the right edge has failed even when there is coordinate data registered as the right edge data of the document, assuming that it is erroneously registered as the right edge data of the document.

  Examples of cases where the detection of the right edge fails include a case where the document size is larger than the size of the document table 11a and the right edge of the document protrudes from the document table 11a.

  If it is determined that the detection of the right edge has failed (Yes in S430), the CPU 70 proceeds to S431 and executes error processing. For example, the multi-function device 1 displays, as an error process in S431, a message prompting the user to input another copy command because the document is placed correctly or the automatic scaling copying function cannot be used. After the display, the process can be configured to execute the process of forcibly terminating the copy control process corresponding to the copy command that led to the execution of S431 and invalidating the copy command.

  In addition, the multi function device 1 performs the error processing in S431 as follows: “The size of the document placed on the document table 11a is formally estimated to be a predetermined fixed size, and the inclination angle θ of the document is determined. Further, it is estimated that the original is placed on the area where the original is placed when it is assumed that the lower left corner of the estimated size of the original is correctly abutted against the lower left corner of the original table 11a. The “estimating” process may be executed, and then the document estimation process may be terminated and the process may proceed to S250.

  On the other hand, if it is determined in S430 that the right edge has been successfully detected (No in S430), the CPU 70 proceeds to S433 and linearly approximates each point indicated by the document right edge data determined in the right edge detection process. An approximate straight line of the point group indicated by the original right edge data (hereinafter referred to as “right edge approximate straight line”) is calculated.

  When this process is finished, the CPU 70 proceeds to S440 and determines whether or not the right edge approximate straight line is inclined more than a predetermined angle with respect to the Y axis. In this embodiment, specifically, it is determined whether or not the right edge approximate straight line is inclined more than 0.5 degrees with respect to the Y axis.

  If it is determined that the slope of the right edge approximate straight line is equal to or smaller than the predetermined angle (No in S440), the CPU 70 is placed on the document table 11a by being abutted against the inner left lower corner of the frame 13a. As shown in the right diagram of FIG. 7, the intersection of the right edge approximate straight line and the lower edge of the document table 11a is estimated to be the lower right corner position of the document (S441).

  When this processing is completed, the CPU 70 estimates that the lower left corner position of the document is the lower left corner point of the document table 11a (S443), and based on the position coordinates of the angular position estimated in S441 and S443, the document table. Under the assumption that the original placed on the original 11a is a standard paper, the size of the original placed on the original table 11a and the placement area of the original on the original table 11a are estimated, and the inclination angle of the original is set. θ is estimated (S445).

  Specifically, the length from the lower left corner position to the lower right corner position of the document estimated in S441 and S443 is estimated as the short side length (horizontal width) of the document, and √2 times the short side length is The document size is estimated by estimating the long side length (vertical width) of the document, and the document of the document size is placed on the document table 11a based on the estimated lower left corner position and lower right corner position. As an example, the coordinates at which the upper left corner and the upper right corner of the document are located are derived, and an area within a quadrilateral formed by connecting these four corners is estimated as the document placement area. Here, the reason why √2 times the original short side length is estimated as the long side length of the original is that the ratio of the short side length to the long side length of the standard paper is 1: √2. This is because.

  Further, in S441 and S443, the angular position is obtained on the assumption that the document is placed on the document table 11a by being accurately abutted against the lower left corner of the document table 11a. It is estimated that θ is zero (no slope).

  When the process in S445 is completed in this way, the CPU 70 ends the document estimation process (S235), proceeds to S250, and executes the subsequent process as described above. That is, based on the document size estimated by the document estimation process, the document tilt angle, and the document placement area information, the scaling factor and tilt correction amount are set (S261, S263), and the reading area is set (S265). ). Thereafter, the process shifts to the main scan (S270), and the copy operation is realized.

  If the story is returned to S440 (see FIG. 7) of the document estimation process, the CPU 70 determines that the right edge approximate straight line is inclined more than a predetermined angle with respect to the Y axis (Yes in S440), the process proceeds to S450. Then, the left edge detection process shown in FIG. 11 is executed. FIG. 11 is a flowchart showing the left edge detection process executed by the CPU 70.

  When the left edge detection process is started, the CPU 70 sets the sub-scanning direction inspection position Ye = 0 in S710, and sets the main scanning direction inspection position Xe to the left end X coordinate of the readable area R0 in S715. (Xe = 0). In S715, the variable C is initialized to zero (C = 0).

  Thereafter, the CPU 70 determines whether or not the sub-scanning direction inspection position Ye exceeds the inspection range (that is, whether or not Ye> S) (S720), and the sub-scanning direction inspection position Ye exceeds the inspection range. If it is determined that it is not (No in S720), the inspection position (Xe, Ye) is an edge point with reference to the pixel value of the inspection target data corresponding to the inspection position (X, Y) = (Xe, Ye). Whether or not (S725).

  If it is determined that the inspection position (Xe, Ye) is not an edge point (No in S725), the process proceeds to S740, and the main scanning direction inspection position Xe is updated to a point moved by one pixel in the X axis plus direction ( Xe ← Xe + 1), it is determined whether or not the updated main scanning direction inspection position Xe protrudes from the right end of the readable area R0 (S743). Specifically, it is determined whether Xe> XMAX (S743). If it is determined that the main scanning direction inspection position Xe does not protrude from the right end of the readable area R0 (No in S743), the process proceeds to S720.

  On the other hand, when it is determined in S743 that the main scanning direction inspection position Xe protrudes from the right end of the readable area R0 (when it is determined that Xe> XMAX), the CPU 70 proceeds to S747 and sets the main scanning direction inspection position Xe. The sub scanning direction inspection position Ye is set to a position advanced by 8 pixels in the Y-axis direction (Y ← Ye + 8) while being set to the left end of the readable region R0 (Xe = 0). Thereafter, the process proceeds to S720.

  If the CPU 70 determines that the inspection position (Xe, Ye) is an edge point (Yes in S725), the CPU 70 proceeds to S730 and sets the variable (X0, Y0) to the current inspection position (Xe, Ye). The coordinate value is set (X0 ← Xe, Y0 ← Ye), and the variable Y1 is updated to the value Y1 = Y0 + 8 (S733).

  Thereafter, it is determined whether at least one of the point of coordinates (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (S737). If none of the point of (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (No in S737), the process proceeds to S740.

  On the other hand, when it is determined that at least one of the point of coordinates (X0-1, Y1), the point of coordinates (X0, Y1), and the point of coordinates (X0 + 1, Y1) is an edge point (Yes in S737), Moving to S750, it is determined that the point of coordinates (X0, Y0) is a continuous edge point, and the coordinates (X0, Y0) are temporarily stored as coordinate data of the continuous edge point. .

  When this process is finished, the CPU 70 proceeds to S760, where the coordinates (X0-1, Y1), the coordinates (X0, Y1), and the coordinates (X0 + 1, Y1) are the edge points. One of the points is selected according to a predetermined priority.

  Specifically, in the left edge detection process, higher priority is set for coordinates closer to the left end side of the readable area R0. That is, the point of the coordinates (X0-1, Y1) close to the left end side of the readable area R0 is set to the priority “large”, the point of the coordinates (X0, Y1) is set to the priority “medium”, and the coordinates ( The point of X0 + 1, Y1) is set to the priority “small”. The priority is set in this way because there is nothing on the document table 11a on the left side of the left edge of the document, and there should be no edge point, and the edge point close to the left edge side of the readable area R0. This is because there is a high possibility that the edge point is an edge point corresponding to the left end of the document.

  Therefore, in S760, according to the priority, the point of the coordinate (X0-1, Y1), the point of the coordinate (X0, Y1), and the point of the coordinate (X0 + 1, Y1) are points that are edge points. To select the point with the highest priority. Then, the variable X0 is updated to the X coordinate of the selected point, and the variable Y0 is updated to the Y coordinate of the selected point. Thereafter, the variable C is updated to a value obtained by adding 1 (S763).

  When this process is finished, the CPU 70 determines whether or not the value of the updated variable C is C = 8. If the CPU 70 determines that C = 8 is not satisfied (No in S767), the process proceeds to S733. The variable Y1 is updated to Y1 = Y0 + 8. Thereafter, the processing after S737 is executed.

  By such a processing procedure, the CPU 70 checks whether or not the edge points are continuous in the Y-axis direction every eight pixels in the Y-axis direction, as in the right edge detection process (see FIG. 9). If it is determined that C = 8 (Yes in S767), the coordinate data of a total of eight points determined as continuous edge points in S750 are stored in the RAM 80 as document left edge data (S770).

  When this process is finished, the CPU 70 proceeds to S780, determines whether or not the sub-scanning direction inspection position Ye exceeds the inspection range (whether or not Ye> S), and performs the sub-scanning direction inspection. If it is determined that the position Ye does not exceed the inspection range (No in S780), the sub-scanning direction inspection position Ye is updated to a point advanced by 64 pixels (S785), and the process proceeds to S715.

  In this way, the CPU 70 repeatedly detects eight consecutive edge points. When the sub-scanning direction detection position Ye exceeds the inspection range (Yes in S720 or Yes in S780), the process proceeds to S790, and the left edge (original document) is selected from the coordinate data group stored as the original left edge data in S770. The edge data representing the left edge of the document) is deleted as a low-accuracy coordinate data group, and the document left edge data is determined.

  Specifically, in the same manner as the processing in S590, the coordinate data group stored as the document left edge data is clearly continuously located at a position greatly shifted to the document inner area with respect to the coordinate data group having continuity. The inconsistent coordinate data group is removed from the document left edge data, and the document left edge data is determined. Thereafter, the left edge detection process ends. However, the left edge detection process may be configured not to execute the process of S790.

  In addition, when the left edge detection process is completed in this way, the CPU 70 proceeds to S455, linearly approximates each point indicated by the document left edge data determined by the left edge detection process, and the document left edge data is obtained. An approximate straight line (hereinafter referred to as “left edge approximate straight line”) of the point group shown is calculated. Thereafter, the process proceeds to S460.

  However, if there is no coordinate data registered as document left edge data in the immediately preceding left edge detection process, it is determined that detection of the left edge has failed, and the process proceeds to S460 without calculating the left edge approximate straight line. It shall be. In addition, when all or part of the coordinate data registered as the document left edge data is also registered in the document right edge data, the coordinate data of the right edge (the edge point representing the right edge of the document) is incorrect. Even if there is coordinate data registered as document left edge data, it is determined that detection of the left edge has failed, and without calculating the left edge approximate straight line, You may make it transfer to S460.

In step S460, the CPU 70 executes a lower edge detection process shown in FIG. FIG. 12 is a flowchart showing the lower edge detection process executed by the CPU 70.
When the lower edge detection process is started, the CPU 70 sets the main scanning direction inspection position Xe to the left end X coordinate of the readable area R0 (Xe = 0) in S810, and the sub scanning direction inspection position Ye in S815. Is set to the lower end Y coordinate of the readable area R0 (Ye = 0). In S815, the variable C is initialized to zero (C = 0).

  When this process is finished, the CPU 70 determines whether or not the main scanning direction inspection position Xe exceeds the right end of the readable area R0 (that is, whether Xe> XMAX) (S820). If it is determined that the scanning direction inspection position Xe does not exceed the right end of the readable region R0 (No in S820), the pixel value of the inspection target data corresponding to the inspection position (X, Y) = (Xe, Ye) is referred to. Then, it is determined whether or not the inspection position (Xe, Ye) is an edge point (S825).

  If it is determined that the inspection position (Xe, Ye) is not an edge point (No in S825), the process proceeds to S840, and the sub-scanning inspection position Ye is updated to a position moved by one pixel in the Y-axis plus direction. (Ye ← Ye + 1), it is determined whether or not the updated sub-scanning direction inspection position Ye exceeds the inspection range (whether or not Ye> S) (S843).

If it is determined that the sub-scanning direction inspection position Ye does not exceed the inspection range (No in S843), the process proceeds to S820.
On the other hand, when it is determined in S843 that the sub-scanning direction inspection position Ye exceeds the inspection range (when it is determined that Ye> S), the CPU 70 proceeds to S847, and the sub-scanning direction inspection position Ye is set in the readable area. While setting at the lower end of R0 (Ye = 0), the main scanning direction inspection position Xe is set to a position advanced by 8 pixels in the X-axis direction (Xe ← Xe + 8). Thereafter, the process proceeds to S820.

  In addition, when the CPU 70 determines in S825 that the inspection position (Xe, Ye) is an edge point (Yes in S825), the CPU 70 proceeds to S830 and sets the current inspection position (Xe, Y0) in the variable (X0, Y0). The coordinate value of (Ye) is set (X0 ← Xe, Y0 ← Ye). Also, the variable X1 is updated to the value X1 = X0 + 8 (S833).

  Thereafter, the CPU 70 determines whether or not at least one of the coordinates (X1, Y0-1), the coordinates (X1, Y0), and the coordinates (X1, Y0 + 1) is an edge point (S837). ), If any of the point of coordinates (X1, Y0-1), the point of coordinates (X1, Y0), and the point of coordinates (X1, Y0 + 1) is not an edge point (No in S837), the process proceeds to S840. .

  On the other hand, if it is determined that at least one of the coordinates (X1, Y0-1), the coordinates (X1, Y0), and the coordinates (X1, Y0 + 1) is an edge point (Yes in S837), the CPU 70 Moving to S850, it is determined that the point of coordinates (X0, Y0) is a continuous edge point, and this coordinate (X0, Y0) is temporarily stored as coordinate data of a continuous edge point. .

  When this process is finished, the CPU 70 proceeds to S860, where the coordinates (X1, Y0-1), the coordinates (X1, Y0), and the coordinates (X1, Y0 + 1) are the edge points. One of the points is selected according to a predetermined priority.

  Specifically, in the lower edge detection process, a higher priority is set for coordinates closer to the lower end side of the readable area R0. That is, the point of the coordinates (X1, Y0-1) close to the lower end side of the readable area R0 is set to the priority “large”, the point of the coordinates (X1, Y0) is set to the priority “medium”, and the coordinates ( The point of (X1, Y0 + 1) is set to the priority “small”. The priority is set in this way because there is nothing on the document table 11a below the lower end of the original, there should be no edge point, and the edge close to the lower end of the readable area R0. This is because the point is more likely to be the edge point corresponding to the lower end of the document.

  Therefore, in S860, according to this priority, the point that is the edge point among the point of the coordinate (X1, Y0-1), the point of the coordinate (X1, Y0), and the point of the coordinate (X1, Y0 + 1) is preferred. Select the point with the highest degree. Then, the variable X0 is updated to the X coordinate of the selected point, and the variable Y0 is updated to the Y coordinate of the selected point. Thereafter, the variable C is updated to a value obtained by adding 1 (S863).

  When this process is finished, the CPU 70 determines whether or not the value of the updated variable C is C = 8 (S867). If it is determined that C = 8 is not satisfied (No in S867), the process proceeds to S833. Then, the variable X1 is updated to X1 = X0 + 8. Thereafter, the processing after S837 is executed.

  By executing such processing, the CPU 70 checks whether the edge points are continuous in the X-axis direction every 8 pixels in the X-axis direction. If it is determined that C = 8 (Yes in S867), the coordinate data of a total of eight points determined as continuous edge points in S850 are stored in the RAM 80 as document lower edge data (S870).

  When this process is finished, the CPU 70 proceeds to S880 to determine whether the main scanning direction inspection position Xe exceeds the right end of the readable area R0 (whether Xe> XMAX). If it is determined that the scanning direction inspection position Xe does not exceed the right end of the readable region R0 (No in S880), the main scanning direction inspection position Xe is updated to a point advanced by 64 pixels (S885), and the process proceeds to S815.

  In this way, the CPU 70 repeatedly detects eight consecutive edge points. When the main scanning direction detection position Xe exceeds the right end of the readable area R0 (Yes in S820 or Yes in S880), the process proceeds to S890, and the coordinate data group stored as the document lower edge data in S870 is The coordinate data group with low accuracy is deleted as an edge (edge point representing the lower end of the document), and the document lower edge data is determined.

  Specifically, as in the process at S590, the coordinate data group stored as the document lower edge data is clearly continuously located at a position greatly shifted to the inner area of the document with respect to the coordinate data group having continuity. The inferior coordinate data group is removed from the document lower edge data to determine the document lower edge data. Thereafter, the lower edge detection process ends. However, the lower edge detection process may be configured not to execute the process of S890.

  In addition, when the lower edge detection process is completed in this way, the CPU 70 proceeds to S465, linearly approximates each point indicated by the document lower edge data determined by the lower edge detection process, and the document lower edge data is obtained. An approximate straight line (hereinafter referred to as a “lower edge approximate straight line”) of the indicated point group is calculated. Thereafter, the process proceeds to S470. However, if there is no coordinate data registered as the document lower edge data in the immediately preceding lower edge detection process, it is determined that the lower edge detection has failed, and the process proceeds to S470 without calculating the lower edge approximate straight line. It shall be.

  In step S470, the CPU 70 determines the right edge detection process (S420), the left edge detection process (S450), and the lower edge detection process from the mutual relationship between the right edge approximate line, the left edge approximate line, and the lower edge approximate line. In (S460), it is determined whether or not the document edge is correctly detected. That is, it is determined whether all of the right edge, the left edge, and the lower edge have been detected normally.

  Specifically, the right edge approximate line and the left edge approximate line are parallel, the right edge approximate line and the lower edge approximate line are orthogonal, and the left edge approximate line and the lower edge approximate line are orthogonal If there is a relationship, it is determined that the document edge is correctly detected, and the determination in S470 is Yes.

  On the other hand, if detection of any one of the right edge, the left edge, and the lower edge fails, or if the relationship between the right edge, the left edge, and the lower edge is not correct, it is determined No in S470. . That is, the right edge approximate line and the left edge approximate line are parallel, the right edge approximate line and the lower edge approximate line are orthogonal, and the left edge approximate line and the lower edge approximate line are orthogonal. Except in the case of No., it is determined that the document edge is not correctly detected, and No is determined in S470. However, the determination of the mutual relationship here should be executed in consideration of an error.

If it is determined that the document edge is not correctly detected (No in S470), the CPU 70 proceeds to S471 and executes error processing similar to the processing in S431.
On the other hand, if it is determined in S470 that the document edge is correctly detected (Yes in S470), the CPU 70 proceeds to S480, and the lower left corner position of the document is determined by the intersection of the left edge approximate line and the lower edge approximate line. Assuming that there is a coordinate value, the coordinate value is calculated. Further, the lower right corner position of the document is estimated to be the intersection of the right edge approximate line and the lower edge approximate line, and the coordinate value is calculated (S485). . FIG. 13 is an explanatory diagram showing a method for estimating the document lower left corner position Ka and the document lower right corner position Kb in S480 and S485. In the figure, white circles represent edge points, and black circles represent the corner positions Ka and Kb.

  When the process in S485 is completed, the CPU 70 assumes that the document placed on the document table 11a is a standard sheet based on the position coordinates of the angular position estimated in S480 and S485. The size of the document placed on the table 11a and the document placement area on the document table 11a are estimated, and the inclination angle θ of the document placed on the document table 11a is estimated based on the right-edge approximate straight line ( S490).

  That is, the length from the lower left corner position to the lower right corner position of the document estimated in S480 and S485 is estimated as the short side length (horizontal width) of the document, and √2 times the short side length is set to the document length. Assume that the document size is estimated by estimating the side length (vertical width), and the document of the document size is placed on the document table 11a based on the estimated lower left corner position and lower right corner position. The coordinates where the upper left corner and the upper right corner of the document are located are derived, and an area within a quadrilateral formed by connecting these four corners is estimated as the document placement area.

  In addition, in S490, the angle formed by the right edge approximate line with respect to the Y axis is estimated as the document inclination angle θ. When this process ends, the CPU 70 ends the document estimation process in S235, proceeds to S250, and executes the subsequent process.

  By such an operation, the CPU 70 detects the document edge from the edge image data (inspection target data) obtained by the pre-scanning when it is not detected that the document runs on the frame 13a, and based on the detection result. Under the assumption that the document is a standard sheet, the size of the document placed on the document table 11a, the placement area of the document, and the inclination angle of the document are estimated (S490). Based on the estimation result, a scaling factor and an inclination correction amount are set (S261, S263), and a reading area is further set (S265). Thereafter, the process proceeds to the main scan (S270).

  In the main scan (S270), the reading unit 15 is transported under the set reading area, and the reading unit 15 is caused to read an image shown in the area. Then, the read result is enlarged / reduced in accordance with the set variable magnification, and rotated in accordance with the set inclination correction amount to generate image data for printing. Also, by printing this as print target data, a copy image of the original, which has been automatically scaled and further tilt-corrected, is printed on recording paper through the printing unit 30.

  The configuration of the digital multi-function peripheral 1 according to the present embodiment has been described above. However, the multi-function peripheral 1 according to the present embodiment detects the document edge from the read result of the pre-scan, and the document state (document size / document size). Inclination / document placement area) is estimated. For this reason, when a large document of an allowable size such as a newspaper is placed on the document table 11a, if the document edge is detected and the document state is estimated from the pre-scan reading result, the document size or the like is erroneously determined. There is a possibility of estimation. For this reason, in the present embodiment, when the original is detected from the luminance distribution at the end of the original table 11a and the original is on the frame 13a, the original edge is detected from the prescan result. The document size is estimated to be the maximum size that can be placed on the document table 11a without obtaining the document size or the like.

  Therefore, according to the present embodiment, even when a large document larger than an allowable size such as a newspaper is placed on the document table 11a, it is possible to appropriately estimate the document size and execute subsequent processing. It is possible to suppress as much as possible the influence on subsequent processing (magnification / reading area setting operation) by erroneously estimating the document size or the like. For example, although a large document such as a newspaper is placed on the document table 11a, the user faces the document table 11a by being confused by the ruled lines in the document and erroneously estimating the document size. Even though it is desired to copy the entire area of the document, it is possible to avoid performing a copy operation for only a part of the area.

  Further, in this embodiment, the height h ′ from the surface of the document table 11a of the right frame 13a (R) located on the opposite side of the document table 11a with respect to the left frame 13a (L) against which the document is abutted, By setting the height of the left frame 13a (L) higher than the height h from the surface of the document table 11a, it is possible to maximize the document table 11a while suppressing the distortion of the read image of the document that has run on the frame 13a as much as possible. Since it is possible to detect with high sensitivity from the length of the black area length L that a document of a size or larger is placed, the highly convenient multifunction machine 1 can be provided to the user.

  That is, in order to detect with high sensitivity that the document has been placed on the frame 13a, it is preferable to increase the height of the frame 13a from the surface of the document table 11a. However, if the height of the frame 13a is increased, the height of the frame 13a increases. Since the document is greatly distorted at the end of the document table 11a, the image quality of the read image at the end of the readable area R0 is deteriorated. For this reason, it is never preferable to increase the height of the entire frame 13a in order to detect with high sensitivity an exceptional case in which a document of the maximum size or more is placed on the document table 11a.

  For this reason, in this embodiment, as described above, only the height h ′ from the surface of the document table 11a of the right frame 13a (R), which is an area for detecting the rising of the document, is set large. The heights h of the frames 13a (L), 13a (U), and 13a (D) from the surface of the document table 11a are uniformly set to the same height h (<h ′).

  In this embodiment, since the lower left corner of the original is in contact with the lower left corner of the original platen 11a, the original placed on the original platen 11a has a size exceeding the readable area R0. However, there are few cases in which the document runs on the left frame 13a (L) or the lower frame 13a (D). On the other hand, when a document having a size exceeding the readable area R0 is placed on the document table 11a, the document runs on the right frame 13a (R) with high probability.

  Accordingly, the height h ′ of the right frame 13a (R) located on the opposite side of the document table 11a from the surface of the document table 11a with respect to the left frame 13a (L) against which the document is abutted is set to the left frame 13a (L). ) Is set higher than the height h from the surface of the document table 11a, the deterioration of the image quality of the read image is suppressed as much as possible, and a document of a size larger than the maximum size is placed on the document table 11a. Sensitivity can be detected from the length.

  In addition, in the MFP 1 of this embodiment, a partial area of the readable area R0 is pre-scanned, and based on the reading result, the state of the original (original size, original inclination, original placement area) is determined. Thus, according to the present embodiment, the prescan operation can be completed at a higher speed than the conventional method of prescanning the entire readable region R0, and the state of the document can be efficiently performed. Can be estimated.

Further, in the above, because the multi-function device 1 is designed so that the pre-scan is performed not on the entire readable area R0 but only on a partial area, the detection of the document on the right frame 13a ( R), but when the multi-function peripheral 1 is configured to perform pre-scan on the entire readable area R0, the detection of the document is detected through the upper frame 13a (U). May be.
[Modification]
FIG. 14 is an explanatory diagram showing a configuration around the document table 11a of the image reading unit 10 in a modified example. FIG. 14 is a plan view, and FIG. 14 is a cross-sectional view taken along line BB ′.

  As shown in FIG. 14, in the modification, the height h ′ of the upper frame 13a (U) in contact with the upper edge of the document table 11a from the surface of the document table 11a is lower frame 13a (in contact with the lower edge of the document table 11a). D) is set to a value higher than the height h from the surface of the document table 11a (h ′> h).

  Further, in the modification, the processes of S210 and S235 of the automatic scaling copying process executed by the CPU 70 are respectively replaced with the processes of S211 and S236 described below, and the ride determination process executed in S220 is shown in FIG. The contents shown in FIG.

  FIG. 15 is a flowchart showing a part of the automatic scaling copying process executed by the CPU 70 in the modification, and FIG. 16 is a flowchart showing the riding determination process executed by the CPU 70 in the modification. .

  As shown in FIG. 15, when the CPU 70 of the modified example starts the automatic scaling copying process, first, the document reading start position is set at the lower end (Y = 0) of the readable area R0, and the document reading end position is set. By setting the upper end of the readable area R0 (Y = YMAX), the entire readable area R0 is set as a reading area (in other words, a pre-scan area). A pre-scan operation is performed on the entire readable area R0 (S211: whole pre-scan process).

  When this process is finished, the CPU 70 converts the RGB value of each pixel indicated by the prescan image data recorded in the RAM 80 into a luminance value Z according to a predetermined calculation formula, thereby converting the prescan image data into It converts into the luminance data showing the luminance value of each pixel (S215), and a riding-up determination process is executed based on the generated luminance data (S220). However, the boarding determination process shown in FIG. 16 is executed here.

  When the boarding determination process shown in FIG. 16 is started, the CPU 70 first sets the main scanning direction inspection position Xe to the inspection start position XINI predetermined in the design stage (Xe = YINI) in S910. When the processing in S910 is completed, the CPU 70 proceeds to S921 and sets the sub-scanning direction inspection position Ye to the Y coordinate of the upper end of the readable area R0 (Ye = YMAX).

  When this process is completed, the CPU 70 refers to the luminance data to obtain the luminance value Z of the pixel corresponding to the inspection position (X, Y) = (Xe, Ye), and this inspection position (Xe, It is determined whether or not the luminance value Z of the pixel corresponding to Ye) exceeds a predetermined threshold value Zth (S923).

  If it is determined that the luminance value Z is equal to or less than the threshold value Zth (that is, Z ≦ Zth) (No in S923), the CPU 70 proceeds to S925 and sets the sub-scanning direction inspection position Ye in the minus direction by one pixel. After updating to the value shifted to (that is, after updating to Ye ← Ye−1), the process proceeds to S927.

  In S927, it is determined whether or not the updated sub-scanning direction inspection position Ye is the lower end of the readable area R0. That is, it is determined whether Ye = 0. When it is determined that the updated sub-scanning direction inspection position Ye is the lower end of the readable area R0 (Yes in S927), the process proceeds to S929.

  On the other hand, if it is determined that Ye> 0 and the updated sub-scanning direction inspection position Ye is not the lower end of the readable region R0 (No in S927), the CPU 70 proceeds to S923 and updates the updated inspection position (X, For Y) = (Xe, Ye), it is determined whether or not the luminance value Z of the pixel corresponding to this inspection position exceeds the threshold value Zth.

When it is determined that the luminance value Z of the pixel corresponding to the inspection position exceeds the threshold value Zth (Yes in S923), the process proceeds to S929.
In S929, the Y-axis direction length L from the upper end of the readable area R0 to the currently set sub-scanning direction inspection position Ye is set to the black area length L (X = Xe) at the point of the coordinate X = Xe. Calculate as That is, the black area length L (X = Xe) at the point of the coordinate X = Xe is calculated according to the equation L = YMAX−Ye.

  When the process in S929 is completed, the CPU 70 proceeds to S930 and updates the main scanning direction inspection position Xe to a position moved by one pixel in the X axis plus direction (Xe ← Xe + 1). Thereafter, it is determined whether or not the main scanning direction inspection position Xe exceeds the inspection end position XFIN predetermined in the design stage (S940). The inspection end position XFIN is set to a value between 0 and XMAX by the designer at the design stage, as with the inspection start position XINI. However, as a matter of course, the inspection end position XFIN is determined as a value larger in the X-axis plus direction than the inspection start position XINI (XFIN> XINI).

  If the CPU 70 determines that the main scanning direction inspection position Xe does not exceed the inspection end position XFIN (that is, determines that Xe ≦ XFIN), the CPU 70 proceeds to S921 and executes subsequent processing. By repeating such an operation, the CPU 70 calculates the black area length L (X) with the upper end of the readable area R0 area as the base point at each coordinate X from the inspection start position XINI to the inspection end position XFIN by the above-described method. calculate.

  If it is determined that the main scanning direction inspection position Xe exceeds the inspection end position XFIN (Yes in S940), the CPU 70 proceeds to S950 and calculates each coordinate X in the range of XINI ≦ X ≦ XMAX calculated in S929. The average value AVE (L) of the black area length L (X) is calculated using the value of the black area length L (X).

  When the process in S950 is completed, the CPU 70 determines whether or not the average value AVE (L) is equal to or greater than a predetermined threshold Lth (S960). If it is determined that the average value AVE (L) is equal to or greater than the threshold value Lth (Yes in S960), it is determined that the document is on the upper frame 13a (U) (S970). On the other hand, if it is determined that the average value AVE (L) is less than the threshold value Lth (No in S960), it is determined that the document is not carried on the upper frame 13a (U), and a “no ride” determination is made (SS980).

Thus, when the process of S970 or S980 is completed, the CPU 70 ends the ride-up determination process and proceeds to S225.
When the process proceeds to S225, the CPU 70 determines whether or not the “ride on” determination is made in the ride determination process executed in the immediately preceding S220, and the “ride on” determination is not made. If it is determined that the “no” determination is made (No in S225), the process proceeds to S230.

  In S230, edge detection processing is performed on the luminance data corresponding to the pre-scan image data recorded in the RAM 80, and edge image data corresponding to the image data is generated. When the processing in S230 is completed, the CPU 70 proceeds to S236, detects the document edge from the generated edge image data, and based on the detection result, the size of the document placed on the document table 11a ( (Vertical width and horizontal width), the inclination angle θ of the document, and the document placement area on the document table 11a are estimated. In S236, as in S235, the document estimation processing shown in FIG. 7 may be executed, or the upper edge is detected as the document edge in addition to the left edge, right edge, and lower edge, and approximation thereof is performed. The document size or the like may be estimated from the straight line.

  In this way, when the processing in S236 is completed, the CPU 70 proceeds to S250 and executes the subsequent processing in the same manner as in the above embodiment. In addition, if it is determined that the “ride on” determination has been made (Yes in S225), the CPU 70 proceeds to S241 and executes the subsequent processing in the same manner as in the above embodiment.

The configuration of the MFP 1 according to the modification has been described above, but the same effect as that of the above-described embodiment can be obtained in this modification.
Moreover, although the embodiment of the present invention including the modification has been described above, the state determination unit of the present invention is realized by the processing of S215 and S220 executed by the CPU 70, and the notification unit is realized by the processing of S241. The document estimation unit is realized by the processing of S225 to S247 executed by the CPU 70.

  Further, the present invention is not limited to the above-described embodiments, and can take various forms. For example, when the multifunction device 1 pre-scans the entire readable area R0 and a document is placed on one of the right frame 13a (R) and the upper frame 13a (U) based on the pre-scan result. It may be configured to determine “riding on” and to determine “no riding” only when the document is not riding on either the right frame 13a (R) or the upper frame 13a (U). .

2 is an explanatory diagram illustrating a configuration of a digital multi-function peripheral 1. FIG. 2A is a plan view of the image reading unit 10 showing the configuration around the document table 11a, FIG. 3B is a cross-sectional view along A-A ′ around the document table 11a, and FIG. 6 is a flowchart illustrating a copy control process executed by a CPU. 6 is a flowchart showing an automatic scaling copying process executed by a CPU. It is a flowchart showing the boarding determination process which CPU70 performs. FIG. 6 is an explanatory diagram showing a luminance distribution at an end portion of a document table 11a. 6 is a flowchart showing document estimation processing executed by CPU. It is a flowchart showing the right edge detection process which CPU70 performs. It is explanatory drawing which showed the structure of edge image data. FIG. 6 is an explanatory diagram illustrating a method for determining original right edge data. It is a flowchart showing the left edge detection process which CPU70 performs. It is a flowchart showing the lower edge detection process which CPU70 performs. FIG. 5 is an explanatory diagram showing a method for estimating a document lower left corner position and a document lower right corner position. FIG. 10 is a plan view and a B-B ′ sectional view of an image reading unit 10 showing a configuration around a document table 11 a of a modified example. 10 is a flowchart showing a modified automatic scaling copying process executed by a CPU. It is a flowchart showing the boarding determination process of the modification which CPU70 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital compound machine, 10 ... Image reading part, 11 ... Reading glass, 11a ... Original plate, 13 ... Housing | casing, 13a ... Frame, 15 ... Reading unit, 16 ... Conveyance mechanism, 17 ... Motor, 20 ... Reading control part , 30 ... printing section, 40 ... print control section, 50 ... display operation section, 60 ... communication section, 70 ... CPU, 80 ... RAM, 90 ... flash memory, MK ... mark, P ... original, R0 ... readable area

Claims (5)

A reading unit is conveyed under a transparent document table on which a document to be read is placed, and an image on the document table is read by the reading unit, whereby a read image of the document placed on the document table is read. An image reading device for generating image data representing
A frame surrounding the periphery of the document table on the periphery of the document table;
The frame forms a step at the boundary between the document table and the frame, with the frame as a high level and the document table as a low level.
Furthermore, the image reading apparatus
A part of the document placed on the document table, based on the distribution of luminance of each pixel indicated by the image data around the boundary between the document table and the frame, which is image data that is a reading result of the reading unit An image reading apparatus comprising: state determination means for determining whether or not the vehicle is on the frame. The state determination means determines the length of the black region whose luminance spreading from the boundary between the document table and the frame is below a threshold value from information on the luminance of each pixel indicated by image data around the boundary between the document table and the frame. When the length of the black area is equal to or longer than a predetermined distance, it is determined that a part of the document placed on the document table is in a state of being on the frame. The image reading apparatus according to claim 1. The specific edge of the document table is defined as a document abutting position where the document should be abutted,
The height of the step formed by the document abutting position from the surface of the document table formed by a portion of the frame existing symmetrically with respect to the document table is the frame corresponding to the document abutting position. The image reading apparatus according to claim 1, wherein the step formed by the portion is set to be higher than a height from the surface of the document table. When a part of the document placed on the document table is in the state of being on the frame based on the determination result of the state determination unit, a notification unit is provided to notify the user to that effect. The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. Document estimation for detecting an edge of a document placed on the document table based on image data as a reading result of the reading unit and estimating a size of the document placed on the document table based on the detection result Means
When the state determination unit determines that a part of the document is on the frame, the document estimation unit determines whether the document placed on the document table is independent of the edge detection result. The image reading apparatus according to claim 1, wherein the size is estimated to be a maximum size that can be placed on the document table.

Images