JP2019050466A - Image reader image reading program - Google Patents

Abstract

To provide an image reader and image reading program, capable of preventing an image reading section from moving excessively from a right end of a spread document to a region in which no document exists.SOLUTION: An image reader 1 includes an original platen 2, a reading section 4, a driving section 5, an edge image formation section 103 and a control section 90. The control section 90 executes reading processing (S3-S7), edge determination processing (S201 and S205-S209), concentration determination processing (S301 and S304-S306) and movement stopping processing (S215) which makes the driving section stop the reading section when the concentration determination processing determines a percentage of a concentration determination object range to total pixel number is at least a third threshold value.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image reading apparatus and an image reading program.

  Conventionally, as described in Patent Document 1, based on the detection results of a plurality of optical sensors provided below the contact glass, the sheet length of the document placed on the contact glass is detected, and the image reading unit is detected. There is known an image reading apparatus which detects the sheet width of an original based on incident light and causes the image reading unit to read image data of an original size of the detected sheet length and sheet width.

JP, 2014-30078, A

  In the image reading apparatus described in Patent Document 1, it is conceivable to read the image of each page of the spread original and manage the image data of each page.

  In the image reading apparatus described in Patent Document 1, when placing a spread original on contact glass, the saddle-stitched portion of the spread original is bent and the left end of the left page of the spread original in contact with the contact glass is the right end of the right page. The paper length up to (paper length from the left end to the right end) is shorter than the original paper length.

  In the above image reading device, when the user places the double-page spread original in a direction in which the saddle-stitched part of the double-page spread original is parallel to the main scanning direction, the image reading device is a sheet of fixed size longer than the original sheet length. Detect as a length. The image reading apparatus reads an image while moving the image reading unit in the sub-scanning direction from the left end of the document to the sheet length of the fixed size in order to read the image of the double-page spread document. There is a problem that an extra portion is moved to the area where the document does not exist at the right end.

  The present invention has been made to solve the above-mentioned problems, and an image reading apparatus capable of preventing an extra movement from the right end of the image reading unit to the area where the document is not present, and the image reading unit The program can be provided.

  In order to achieve the above object, according to the first aspect of the present invention, an image reading apparatus comprises: a document holder for supporting a document; a reading unit for reading a line image of the document in the main scanning direction; An edge emphasizing process is performed on image data relating to the line image read by the reading unit and a driving unit that moves the reading unit from the reading start position to the reading end position in the sub scanning direction orthogonal to each other; The control unit includes an edge image generation unit that generates data, and a control unit, and the control unit causes the drive unit to move the reading unit from the reading start position in the sub scanning direction toward the reading end position. A reading process for causing the reading unit to read the line image, and a plurality of pixels and the main running in the sub scanning direction from the edge image data generated by the edge image generating unit The edge pixel value of the edge determination target range including a plurality of pixels in the direction is acquired, and the edge pixel value of the plurality of pixels along the sub-scanning direction is acquired for the acquired edge pixel value of the edge determination target range Edge determination processing for determining whether any one of the plurality of pixels is greater than or equal to the first threshold value for each of the plurality of pixels along the main scanning direction; If it is determined that any one of the edge pixel values of the plurality of pixels along the sub scanning direction is equal to or greater than the first threshold value in all the plurality of pixels, the image data corresponds to the edge determination target range From the image data closer to the reading end position in the sub scanning direction than the scanning position, the density determination including a plurality of pixels in the sub scanning direction and a plurality of pixels in the main scanning direction A pixel value of a target range is acquired, and the concentration judgment target which becomes a pixel value equal to or less than a second threshold except for the obtainable minimum value and the maximum value of the pixel value of the acquired concentration judgment target range When it is determined that the ratio is equal to or more than the third threshold value by the density determination process of determining whether the ratio corresponding to the total number of pixels in the range is equal to or more than the third threshold value; And moving stop processing for causing the drive unit to stop the reading unit moving in the sub scanning direction.

  According to the aspect of the present invention, in the image reading apparatus which automatically conveys and reads the document supported by the document tray, the control unit executes the movement stop process to open the document from the right end of the image reading unit It is possible to prevent extra movement to an area where there is no

  According to a specific aspect of the present invention, the control unit is configured to execute the edge determination processing in at least one or more pixels among the plurality of pixels along the main scanning direction along the sub scanning direction. When it is determined that all the edge pixel values related to all the plurality of pixels are less than the first threshold value, a predetermined number of pixels are separated from the edge determination target range toward the reading end position in the sub scanning direction When it is determined that the ratio is less than the third threshold value by the edge determination control processing of re-executing the edge determination processing with the edge determination target range as a new edge determination target range and the density determination processing, the edge determination A position away from a position corresponding to the target range to a predetermined number of pixels toward the reading end position in the sub scanning direction corresponds to a new edge determination target range And density determination control process for executing the concentration determination process as location again, to run.

  The control unit executes the edge determination control process and the density determination control process, for example, as a result of the previous edge determination process, at least one of the plurality of pixels along the main scanning direction as a result of the edge determination process. When it is determined that all edge pixel values pertaining to all the plurality of pixels along the scanning direction are less than the first threshold, or as a result of the previous density determination processing, pixel values for pixel values in the density determination target range Of the movement stop process even if the ratio corresponding to the total number of pixels in the density determination target range which is a pixel value equal to or less than the second threshold except for the possible minimum value and maximum value is less than the third threshold Make it possible to do it.

  According to a specific aspect of the present invention, after the start of the reading process, the control unit detects the leading edge or the side edge of the document in the edge image data to thereby detect the main scanning document width of the document and An original determination process for determining the main scanning original inclination of the original is executed, and the edge determination target range is determined by the control unit based on the main scanning original width and a plurality of pixels in the main scanning direction and the main scanning original It is a range consisting of a plurality of pixels in the sub scanning direction determined based on the width and the main scanning document inclination, and the new edge determination target range is the end of reading in the sub scanning direction from the edge determination target range This is an edge determination target range separated by one pixel toward the position.

  The control unit executes document determination processing, and the edge determination target range is determined based on the plurality of pixels in the main scanning direction determined based on the main scanning document width, the main scanning document width, and the main scanning document inclination. The original is determined by setting the range including a plurality of pixels in the scanning direction and setting the new edge determination target range as an edge determination target range separated from the edge determination target range to the reading end position in the sub scanning direction up to one pixel. Even when tilted with respect to the main scanning direction, one of the edge pixel values of a plurality of pixels along the sub-scanning direction is equal to or greater than the first threshold in all of the plurality of pixels along the main scanning direction. Therefore, the determination accuracy in the edge acquisition determination process can be improved.

  According to a fourth aspect of the present invention, in the image reading apparatus, the density determination target range is an inclination of the side end portion of the document in the sub scanning direction toward the reading end position with respect to the document table It is a range including a plurality of pixels in the sub-scanning direction and a plurality of pixels in the main scanning direction which are predetermined based on the depth of focus of the reading unit.

  The density judgment target range is a range consisting of a plurality of pixels in the sub-scanning direction and a plurality of pixels in the main scanning direction, which are determined in advance based on the inclination of the side edge of the document to the document table and the focal depth of the reading unit. In the density determination target range, the number of pixels having the pixel value equal to or less than the second threshold is increased except for the possible minimum and maximum values of the pixel value, and the density determination target range is performed without executing the density determination control process. It is possible to increase the possibility that the ratio corresponding to the total number of pixels of the pixel becomes equal to or higher than the third threshold, and to increase the possibility to execute the movement stopping process early.

  In a specific aspect according to claim 5, in the image reading apparatus, the edge determination target range is specified based on specific pixel data which is one pixel data in the main scanning direction in the edge analysis image data. The number of pixel data in the range from the specific pixel data to the main scanning document width from the pixel data to the edge determination target block composed of pixel data from the pixel data to the movement direction and including the range of the edge sub-scanning width in one unit The edge determination process is a range including a plurality of the edge determination target blocks configured along the main scanning direction, and the edge determination process acquires the edge pixel data for each of the edge determination target blocks, and acquires the edge pixel data. All edge judgments are made as to whether or not the edge pixel data exists for each of the edge judgment target blocks at least the first threshold value. The edge judgment control processing determines that the edge pixel data acquired in the one edge judgment target block among the all the edge judgment target blocks is the edge pixel data obtained as a result of the edge judgment processing. If it is determined that the first threshold value or more does not exist, the edge determination process is performed again using pixel data in which the specific pixel data is separated by a predetermined number of pixel data in the movement direction as new specific pixel data.

  After the control unit determines that edge pixel data does not exist in each edge determination target block for all edge determination target blocks, the edge determination process is performed based on new specific pixel data, Edge determination processing can be performed after execution of the read control processing at an early stage.

  According to a specific aspect of the present invention, in the image reading apparatus, the reading unit reads an image of a document for each line in the main scanning direction, and the edge image generator for each line in the main scanning direction. Edge enhancement processing is performed on the analysis image data, and edge image data is generated with an edge pixel as a pixel having a pixel value of each pixel equal to or more than a predetermined threshold in pixel units, for each line in the main scanning direction. The control unit may include a line counter that counts the number of lines in the main scanning direction, and the control unit may determine the number of lines in the main scanning direction based on the main scanning document width determined by the original determination process. Line determination processing and line number determination processing for determining whether the number of lines in the main scanning direction counted by the line counter is equal to the number of lines of the specific line And when it is determined that the counted number of lines in the main scanning direction is equal to the number of lines of the specific line, the edge acquisition is performed based on the specific pixel in the specific line. Execute judgment processing.

  When the control unit executes the line number determination process, it is possible to prevent an erroneous determination that occurs in the edge acquisition determination process based on the information described in the document.

  According to a specific aspect of the present invention, the image reading apparatus comprises an image output unit for outputting image data in a predetermined output range, and the control unit counts the line counter after execution of the reading end processing. Reading end line storing processing for storing the number of read end lines, rear end edge detecting processing for detecting the rear end edge of the original in the edge image data, rear end edge of the detected original, and Rear end line determination processing of determining the number of lines of the rear end edge based on the number of reading end lines, and image extraction processing of extracting image data read by the reading unit based on the rear end edge And an output range determination process of determining the output range based on the main scanning document width, and based on the number of lines of the specific line and the rear end edge. Te, the scanned image data the extracted, and the image output process of placing in the output range the determined, to run.

  The control unit can arrange the read image at the center of the output range in the main scanning direction by executing the image output process.

In the aspect of the invention according to claim 8, the image reading program reads in a sub scanning direction orthogonal to the main scanning direction, a reading unit for reading a line image of the document in a main scanning direction, a document table supporting the document A driving unit that moves the reading unit from a start position to a reading end position, and an edge image generation unit that performs edge enhancement processing on image data related to the line image read by the reading unit and generates edge image data And an image reading program executed by the control unit of the image reading apparatus, wherein the driving unit moves the reading unit from the reading start position in the sub scanning direction to the reading end position. A reading process for causing the reading unit to read the line image, and a plurality of images in the sub-scanning direction from the edge image data generated by the edge image generation unit And acquiring an edge pixel value of an edge determination target range including a plurality of pixels in the main scanning direction, and regarding the edge pixel value of the acquired edge determination target range, the plurality of pixels in the sub scanning direction The main scanning direction is determined by an edge determining process for determining whether any one of the edge pixel values is equal to or more than a first threshold value for each of the plurality of pixels along the main scanning direction, and the edge determining process. When it is determined that any one of the edge pixel values of the plurality of pixels along the sub-scanning direction is equal to or greater than a first threshold value in all of the plurality of pixels along the sub-scanning direction, the edge determination among the image data From the image data closer to the reading end position in the sub scanning direction than the position corresponding to the target range, a plurality of pixels in the sub scanning direction and a plurality of images in the main scanning direction The pixel value of the density determination target range consisting of is obtained, and the obtained pixel value of the density determination target range becomes a pixel value equal to or less than the second threshold except for the minimum value and the maximum value that can be taken of the pixel value. Judgment that the ratio is equal to or more than the third threshold value by the concentration judgment process of judging whether the ratio corresponding to the total number of pixels of the concentration judgment target range is equal to or more than the third threshold value Moving stop processing for causing the drive unit to stop the reading unit moving in the sub-scanning direction;
An image reading program that executes

  According to the aspect of the present invention, in the image reading program executed by the control unit of the image reading apparatus which automatically conveys and reads the document supported on the document tray, the document other than the specific document is executed by executing the transmission control process. Can be prevented from being transmitted to an image transmission destination not intended by the user.

  According to the present invention, it is possible to provide an image reading apparatus and an image reading program that can prevent extra movement from the right end of the image reading unit to the area where the spread document is not present.

1 is a schematic cross-sectional view of a multifunction machine 1 of the present embodiment. FIG. 2A is a top view of the multifunction device 1 of the present embodiment. FIG. 2B is a bird's-eye view of the left end portion BLA of the spread original BK placed on the original placement surface 2a of the multifunction machine 1 according to the present embodiment as viewed from the front and rear direction. FIG. 3A is a block diagram schematically showing an electrical configuration of the multifunction machine 1 of the present embodiment. FIG. 3B is a block diagram schematically showing an electrical configuration of the image processing unit 94 provided in the multifunction machine 1 of the present embodiment. It is a figure which shows the table used by the judgment start line determination process by the multifunctional device 1 of this embodiment. 5 is a flowchart showing main processing by the MFP 1 of the present embodiment. 5 is a flowchart showing an original determination process by the MFP 1 of the present embodiment. 5 is a flowchart showing a reading end determination process by the MFP 1 of the present embodiment. 5 is a flowchart showing a subroutine process of reading end determination processing by the MFP 1 of the present embodiment. 5 is a flowchart showing image output processing by the MFP 1 of the present embodiment. FIG. 10A is a diagram schematically illustrating edge image data for which the document determination process of the present embodiment is performed. FIG. 10B is a bird's-eye view of the right end portion BRA of the spread original BK placed on the original placement surface 2a of the multifunction device 1 of the present embodiment as viewed from the front and rear direction. FIG. 10C is an explanatory view showing the relationship between the number of lines in the sub-scanning direction and the edge pixel value and the density pixel value acquired by the multifunction device 1 of the present embodiment. FIG. 11 is a diagram schematically illustrating the reading end determination process performed by the multifunction device 1 according to the present embodiment. FIG. 12 is a diagram schematically illustrating an image output process performed by the multifunction machine 1 according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment
Hereinafter, the multifunction peripheral 1 of the present embodiment is an example of a specific aspect of the multifunction peripheral of the present invention. First, the configuration of the multifunction device 1 will be described with reference to FIGS. 1 and 2. In FIG. 1 and FIG. 2, the front, rear, left, right, upper and lower directions are displayed. Each direction shown in FIG. 2 is displayed corresponding to each direction shown in FIG. Further, each direction shown in FIG. 9 is also displayed corresponding to each direction shown in FIG.

[Appearance configuration of MFP]
As shown in FIG. 1, the multifunction device 1 includes a platen glass 2, a cover 3, a reading unit 4, and a driving unit 5. The platen glass 2 closes an opening 11 a formed in the upper portion of the rectangular parallelepiped housing 11 of the multifunction machine 1 from the inside of the housing 11. A portion of the upper surface of the platen glass 2 exposed from the opening 11a constitutes a document placement surface 2a on which the spread document BK to be read is placed. One end of the cover portion 3 is rotatably supported on the upper surface of the housing 11, and a closed position (position indicated by a broken line in FIG. 1) covering the document placement surface 2a and the document placement surface 2a are exposed. And an open position (indicated by a solid line in FIG. 1). FIG. 2A shows the position of the reading unit 4 when the MFP 1 is viewed from above with the cover 3 in the open position, and is positioned above the document placement surface 2a. Illustration of the cover part 3 and the drive part 5 is omitted.

  As shown in FIG. 2A, the spread original BK has a left page BKL on the left and a right page BKR on the right with reference to a center line CL (one-dot chain line) at the center of the spread. The left page BKL has a left edge BLA (a range surrounded by a two-dot chain line on the left page BKL) at the left page edge, and the right page BKR has a right edge BRA (right page) at the right page edge. The page BKR has a range enclosed by a two-dot chain line). Specifically, as shown in FIG. 2B, the left end BLA is a left page from the first page of the left page BKL in contact with the original placement surface 2a to the final page stacked upward. It is an end (a range surrounded by a two-dot chain line on the left page BKL). The right end portion BRA is the same as the left end portion BLA in the right side page end portion (FIG. 2B) from the first page of the right page BKR in contact with the document placement surface 2a to the final page stacked upward. Not shown).

  As shown in FIGS. 1 and 2A, an alignment wall 11b constituted by an opening 11a of the housing 11 is provided on the left rear side of the document placement surface 2a. The left rear end point of the alignment wall 11b is the alignment point P of the spread original BK shown in FIG. 2A. When placing the spread original BK on the original placement surface 2a, the user abuts the left rear end of the spread page of the spread original BK in contact with the upper surface of the original placement surface 2a against the alignment wall 11b. Thus, the spread original BK on the original placement surface 2a can be aligned. In this embodiment, as shown in FIG. 2B, the user opens the left rear end of the first page of the left page BKL to the alignment point P, whereby the spread original BK is aligned and placed. It shall be done.

  The reading unit 4 and the drive unit 5 are disposed inside the housing 11 as shown in FIG. The reading unit 4 includes a CIS (Contact Image Sensor) 44 and a carriage 47. The CIS 44 includes an image sensor 41, a light source 43, and a rod lens array 45, and is mounted on the carriage 47. In the reading unit 4 shown in FIG. 2A, only the image sensor 41 is shown. The image sensor 41 is a linear image sensor in which a plurality of light receiving elements (not shown) are arrayed in the main scanning direction (front and back direction in FIG. 2A) shown in FIG. The light source 43 is configured of a light emitting diode or the like, and emits light toward the platen glass 2. The rod lens array 45 focuses the light beam emitted from the light source 43 and reflected by the irradiated object on each light receiving element (not shown) of the image sensor 41. Thereby, the image of the object to be irradiated is read by one line in the main scanning direction.

  As shown in FIG. 1, the drive unit 5 moves the reading unit 4 in a sub-scanning direction (left and right direction in FIG. 1) orthogonal to the main scanning direction. The drive unit 5 includes a drive pulley 51 driven by a motor 59 capable of rotating in the forward and reverse directions, a driven pulley 53, and an endless belt 55 stretched around the drive pulley 51 and the driven pulley 53. The drive pulley 51 is disposed on one end side in the sub scanning direction inside the housing 11, while the driven pulley 53 is disposed on the other end side in the sub scanning direction inside the housing 11. A carriage 47 is attached to the belt 55, and the CIS 44 mounted on the carriage 47 can be reciprocated in the sub scanning direction by moving the belt 55 by rotation of the drive pulley 51 (motor 59). There is.

  An adjustment reference plate 13 shown in FIG. 1 is disposed on the left side of the platen glass 2. The adjustment reference plate 13 is composed of a white tape 13a and a black tape 13b arranged in the sub-scanning direction. The images on the white tape 13a and the black tape 13b are read by the reading unit 4, and the position at which the white pixel changes to black pixel or the position at which the black pixel changes to white pixel corresponding to the image data is shown in FIGS. It is a standby position HP of the reading unit 4 shown in 2 (A). The standby position HP is a reference position in the movement of the reading unit 4 in the sub scanning direction. The CPU 90 (see FIG. 3) causes the drive unit 5 to cause the reading unit 4 to stand by at the standby position HP after the MFP 1 is powered on. Furthermore, the CPU 90 causes the reading unit 4 to read the image of the white tape 13a before executing the reading process described later, and performs correction processing such as acquisition of white reference data used in shading correction (hereinafter referred to as pre-reading correction processing Execute).

  The CPU 90 starts lighting of the light source 43 of the reading unit 4 at the position of the reading start position PS shown in FIGS. 1 and 2A in the reading process described later. The CPU 90 reads an image line by line in the main scanning direction while moving the reading unit 4 from the reading start position PS to the reading end position PE in the sub scanning direction. The reading start position PS and the reading end position PE will be described below.

  As shown in FIGS. 1 and 2A, the reading start position PS is a position at which the reading unit 4 faces the left end of the document placement surface 2a. As shown in FIGS. 1 and 2A, the reading end position PE is a position at which the reading unit 4 faces the right end of the document placement surface 2a. The reading end position PE may be determined by the CPU 90 based on a fixed size (a fixed size such as A5 size) of the double-page spread document BK input by the user from the operation unit 7.

  A display unit 6 such as a liquid crystal display and an organic EL, and an operation unit 7 including various buttons such as a start key, a stop key, and a numeric keypad are provided on the front surface of the housing 11 of the multifunction device 1 (FIG. 3) (A)). The display unit 6 and the operation unit 7 make it possible to display the operation status of the MFP 1 and to input an operation by the user. The display unit 6 and the operation unit 7 may be a touch panel having a display function by the display unit 6 and an input function by the operation unit 7. The image forming unit 10 shown in FIG. 3A described later is not shown.

[Electric configuration of multifunction machine]
The electrical configuration of the multifunction device 1 according to the present embodiment will be described. As illustrated in FIG. 3A, the multifunction device 1 includes a central processing unit (CPU) 90, a read only memory (ROM) 92, a random access memory (RAM) 93, an image processing unit 94, a reading unit 4, and a drive. The unit 5 is provided as part of the configuration. These components are connected to the display unit 6, the operation unit 7, and the image forming unit 10 via the bus 9.

  The CPU 90 controls each part of the multifunction device 1 in accordance with the control program stored in the ROM 92. The ROM 92 stores programs for executing various operations of the multifunction device 1 such as reading processing described later.

  The ROM 92 stores information relating to reading resolution in reading processing to be described later and reading settings such as monochrome reading (one green color) or color reading (three RGB colors). The reading resolution is any of 600 dpi and 1200 dpi. The ROM 92 also stores data representing the amount of movement required for the reading unit 4 to move to the reading start position PS and the reading end position PE with reference to the standby position HP. Note that the reading setting may be determined by the CPU 90 based on the setting input by the user from the operation unit 7. The resolution in the main scanning direction of the CIS 44 constituting the reading unit 4 can be switched to any resolution among 600 dpi and 1200 dpi according to an instruction from the CPU 90.

  Further, as shown in FIG. 4, the ROM 92 stores a table indicating the standard size of the double-page spread original. In the present embodiment, the table showing the fixed size of the spread original is a long side width LW of one page and a short side width of one page shown in FIG. 2A for each of A6 size, A5 size and B5 size. It is a table composed of data indicating SW. More specifically, the data constituting the above-described table has the number of pixels corresponding to 148 mm as the long side width LW for one page and 105 mm as the short side width SW for one page with respect to A6 size. For the A5 size, the number of pixels corresponds to 210 mm as the long side width LW for one page, and to 148 mm as the short side width SW for one page. For the B5 size, the number of pixels corresponds to 257 mm as the long side width LW for one page, and to 182 mm as the short side width SW for one page. In the present embodiment, as shown in FIG. 4, the long side width LW for one page and the short side width SW for one page are respectively set for the number of pixels at a resolution of 300 dpi for each of A6 size, A5 size and B5 size. Are stored in the ROM 92 as a table to be stored.

  The image processing unit 94 is a hardware circuit dedicated to image processing, and as shown in FIG. 3B, the image processing unit 100, the resolution conversion unit 101, the color conversion unit 102, the edge image generation unit 103, and the counter 104. Is composed including.

  The image processing unit 100 performs various image processing on the line data of each of the RGB colors read by the reading unit 4, and stores the line data in the RAM 93. The image processing process is, for example, a rotation process of rotating image data to a predetermined angle such as 90 degrees, an image extraction process of extracting an image in a predetermined range from image data, and the like.

  The resolution conversion unit 101 converts the line data of each of the RGB colors read by the reading unit 4 into a low resolution of 300 dpi by known thinning processing. The resolution conversion unit 101 converts 600 dpi or 1200 dpi line data into 300 dpi line data, for example, by thinning out a plurality of thinning pixels set for all pixels from the first pixel to the last pixel in line data of each RGB color. Do. The resolution conversion unit 101 stores the line image data of each of the RGB colors converted to the low resolution in the RAM 93 as density image data to be determined in the density determination processing described later.

  The color conversion unit 102 performs color conversion processing such as YCbCr conversion and YIQ conversion on the line data of each of the RGB colors converted to low resolution by the resolution conversion unit 101, and calculates luminance values and color difference values for each color. Generate data after color conversion to show.

  The edge image generation unit 103 can execute various types of edge enhancement processing on the data after color conversion generated by the color conversion unit 102 to generate edge image data. In this embodiment, the edge image generation unit 103 executes edge enhancement processing using a Laplacian filter, which is a known difference filter. Specifically, the edge image generation unit 103 applies the Laplacian filter coefficient to the data after color conversion to calculate an edge intensity value of each pixel. The edge image generation unit 103 sets “1” if the calculated edge strength value of each pixel is equal to or more than a predetermined edge strength threshold, and “0” if the calculated edge strength value is less than the edge strength threshold. The edge image data is generated by replacing the pixel value and stored in the RAM 93. The edge intensity threshold value is a value such that data can be replaced with an edge intensity value of a pixel of a line image portion (for example, a character) on an image corresponding to data after color conversion as an edge pixel value of “1”.

  The line counter 104 counts the number of lines of edge image data output from the edge image generation unit 103 to the RAM 93. The start of counting, the end of counting, and the counting reset of the line counter 104 are executed by an instruction from the CPU 90.

  The drive unit 5 includes a drive control unit 54, a driver 52, and a motor 59. The drive control unit 54 is hardware for transmitting a pulse control signal to the driver 52 by PWM to rotate the motor 59. Further, the drive control unit 54 is configured to transmit a signal for controlling forward rotation or reverse rotation of the motor 59 to the driver 52, and to change the rotation direction of the motor 59. The driver 52 controls the timing of the current flowing in the winding of each phase of the motor 59 and the sequence of the current flowing in the winding of each phase according to the pulse control signal and the control signal of the motor rotation direction input from the drive control unit 54 It is hardware configured to be possible. The motor 59 is a stepping motor in the present embodiment.

  The pulse counter 95 counts the number of transmission pulses by one each time the drive control unit 54 transmits a pulse control signal of one pulse. When the CPU 90 instructs the drive control unit 54 to start the rotation of the motor 59, the pulse counter 95 is initialized, and the drive control unit 54 starts counting the number of transmission pulses. When the CPU 90 instructs the drive control unit 54 to stop the rotation of the motor 59, the pulse counter 95 ends the count of the transmission pulse number of the drive control unit 54.

  The motor 59 is rotated by a predetermined rotation angle each time the drive control unit 54 of the drive unit 5 transmits a one-pulse control signal to the driver 52. The amount of rotation of the motor 59 is determined by the number of pulses transmitted by the drive control unit 54. The relationship between the transmission pulse number of the drive control unit 54 and the movement amount of the reading unit 4 in the sub scanning direction is determined in advance, and the movement of the reading unit 4 in the sub scanning direction is determined from the transmission pulse number of the drive control unit 54. Data for calculating the amount is stored in the ROM 92. In this embodiment, the amount of movement corresponds to one line of 600 dpi (25.4 mm / 600 = 0.042 mm) per one transmission pulse number. The ROM 92 stores movement amount data per transmission pulse number indicating that the reading unit 4 moves by one line of 600 dpi per one transmission pulse number counted by the pulse counter 95. The motor 59 is a stepping motor in the present embodiment, but is not limited to this configuration. The motor 59 may be a DC motor with an encoder, and the pulse counter 95 may count the number of pulse signals from the encoder.

  The CPU 90 sets the transmission pulse frequency and the number of transmission pulses to be transmitted to the driver 52 in the drive control unit 54 in the rotation start instruction of the motor 59. The drive control unit 54 controls the rotational speed and rotational speed of the motor 59 by transmitting a pulse control signal according to the setting of the transmission pulse frequency and the number of transmission pulses. The CPU 90 sets the rotation direction of the motor 59 in the forward rotation or the reverse rotation in the drive control unit 54. The drive control unit 54 controls the rotation direction of the motor 59 by transmitting a control signal corresponding to forward rotation or reverse rotation to the driver 52 according to the setting of the rotation direction. The CPU 90 clears the setting of the transmission pulse number and the like of the drive control unit 54 in the instruction to stop the rotation of the motor 59.

  The RAM 93 is used as a storage area for temporarily storing a work area in which various control programs are read, a calculation result calculated by control processing of the control unit 9, and image data read by the reading unit 4.

  The image forming unit 10 forms an image on a recording sheet by an inkjet method, an electrophotographic method, or the like.

[Operation of MFP according to this embodiment]
In the present embodiment, when the user wants to copy the image of the spread original BK onto the recording sheet, the spread original BK is placed on the original placement surface 2 a of the multifunction machine 1 as shown in FIG. . As shown in FIG. 10B, the multi-function device 1 performs reading with the number of reading end lines LE on the side closer to the reading start position PS in the sub scanning direction than the number of lines NSW determined based on the fixed size of the spread original BK. Part 4 can be stopped.

  The multifunction device 1 mainly executes main processing, document determination processing, reading end determination processing, and image output processing. The processes of S1 to S9 in the main process shown in FIG. 5, the processes of S100 to S107 in the document determination process shown in FIG. 6, the processes of S200 to S218 in the reading end determination process shown in FIG. 7 and the subroutine process shown in FIG. The processes of S300 to S306 and the processes of S400 to S412 in the image output process shown in FIG. 9 are processes executed by the first CPU 90.

[Main processing]
The main processing in the MFP 1 of the present embodiment will be described with reference to the flowchart in FIG. When the start key is pressed by the operation unit 7 of the multifunction device 1, the CPU 90 executes main processing shown in FIG. The CPU 90 instructs the drive unit 5 to start forward rotation, rotates the motor 59 forward, and moves the reading unit 4 from the standby position HP to the reading start position PS (S1).

  The CPU 90 calculates the amount of movement of the reading unit 4 in the sub-scanning direction by acquiring the number of transmission pulses with the pulse counter 95, and determines whether the reading unit 4 is located at the reading start position PS shown in FIGS. It is determined whether or not (S2). When it is determined that the reading unit 4 is not located at the reading start position PS (S2: NO), the CPU 90 repeats the determination process of S2. If it is determined that the reading unit 4 is located at the reading start position PS (S2: YES), the CPU 90 causes the reading unit 4 to start reading an image (S3).

  The CPU 90 determines the number of pixels corresponding to the document width which is the width in the main scanning direction of the spread document BK (hereinafter referred to as document width pixel number M) and the document inclination θk in the main scanning direction by document determination processing described later. (S4). The CPU 90 determines the determination start line number LSW, which is the line number at which execution of the reading end determination process described later is started, based on a table showing the document width pixel number M, the document inclination θk, and the fixed size of the spread document (S5) ). Specifically, as shown in FIG. 10A, the CPU 90 multiplies the document width pixel number M detected by the document determination process described later by cos θ k according to the document inclination θ k to generate one page of the spread document BK. The number of pixels LW corresponding to the long side width is calculated, and the number of pixels SW corresponding to the short side width of one page is determined based on the table indicating the standard size of the spread original stored in the ROM 92. The CPU 90 doubles the number of pixels SW corresponding to the short side width for one page, and the pixel from the left end of the left end portion BLA of the spread original BK to the reading start position PS with respect to the number of pixels twice the number of pixels SW. The number ΔSW is subtracted to calculate the number of pixels NSW. As shown in FIG. 2A, the CPU 90 calculates the number of pixels LSW by subtracting the number of pixels RSW corresponding to the short side width of the right end portion BRA of the spread original BK from the number of pixels NSW. The CPU 90 determines the number of pixels LSW as the number of judgment start lines, and stores the number of pixels LSW in the RAM 93. The CPU 90 stores the number of pixels NSW in the RAM 93 in order to use the calculated number of pixels NSW in the process of S305 described later. The CPU 90 may store the number of pixels ΔSW in the ROM 92 as the number of pixels previously confirmed in an experiment. Alternatively, the CPU 90 detects the center line CL of the spread center in the known manner according to the density of the bound portion of the spread original BK, and the number of lines from the reading start position PS to the center line CL of the spread center with respect to the number of pixels SW. The configuration may be such that the number of pixels ΔSW is calculated by subtraction and stored in the RAM 93.

  The CPU 90 acquires the number Lg of lines counted by the line counter 104 until the reading unit 4 moves from the reading start position PS to the current position by the line counter 104, and whether the acquired number Lg of lines is equal to or more than the determination start line number LSW. (S6). If it is determined that the acquired line number Lg is not equal to or more than the determination start line number LSW (S6: NO), the CPU 90 repeats the determination process of S6.

  If it is determined that the acquired line number Lg is greater than or equal to the determination start line number LSW (S6: YES), the CPU 90 executes a reading end determination process described later (S7). The CPU 90 instructs the drive unit 5 to start reverse rotation, and reversely rotates the motor 59 to move the reading unit 4 from the position corresponding to the reading end line LE described later to the standby position HP (S8). The CPU 90 executes an image output process described later (S9).

[Original determination process]
The MFP 1 according to the present embodiment determines the number M of document width pixels of the left page image GL corresponding to the left page BKL of the spread document BK shown in FIG. 10A and the document inclination by the document determination process shown in the flowchart of FIG. Determine θk.

  The document determination process in the multifunction machine 1 will be described with reference to the flowchart of FIG. The CPU 90 initializes the search variable i and stores it in the RAM 93 (S100). The CPU 90 starts searching the side edge point of the left page BKL of the spread original BK in the edge image data stored in the RAM 93, with the search start point corresponding to the search variable i as the start point (S101). The CPU 90 stores the position information of the retrieved side end edge point in the RAM 93 (S102). The CPU 90 determines whether the search variable i is equal to or more than the search end variable N (S103). If it is determined that the search variable i is not equal to or more than the search end variable N (S103: NO), the CPU 90 adds 1 to the search variable i and substitutes it for the search variable i (S107), and repeats the processing from S101.

  Specifically, this will be described with reference to FIG. In FIG. 10A, in order to visually explain the original determination process, the left page BKL of the spread original BK of the edge image in which the data of “1” is indicated by the solid line in the edge image data stored in RAM 93. Is a diagram showing a tip edge image EG1 including only an image GL corresponding to. For simplification of the description, the document information described in the spread document BK in the edge image data is not shown. In FIG. 10A, the outer periphery of the leading edge image EG1 is indicated by an alternate long and short dash line. In FIG. 10A, a plurality of dotted arrows indicate search start points SR (0), SR (1)... SR (N), and SL (0), SL (1),. Indicates the search direction from N). As shown in FIG. 10A, the CPU 90 sets the search start points SL (0) and SR (0) corresponding to the search variable i = 0 which is the side end point of the tip edge image EG1 stored in the RAM 93 to the left. It is set as a search start point of the side end edge point of the page image GL (S101). The CPU 90 searches for the side end edge point D serving as the boundary line of the left page image GL while moving the search point in the direction away from each search start point along the main scanning direction (S101). The CPU 90 stores, in the RAM 93, positional information in the leading edge image EG1 of the retrieved side end edge point D (S102). The CPU 90 extends from the reading start position PS corresponding to the search variable i = 0 in the leading edge image EG1 to a position corresponding to the search end variable N separated by a predetermined distance in the direction approaching the reading end position PE in the sub scanning direction. The side end edge points of the left page image GL are respectively searched. It is assumed that the predetermined distance and the numerical value of the search variable N are determined in advance as a numerical value which can accurately determine the document width pixel number M and the document inclination θk by an experiment and stored in the ROM 92. When the CPU 90 determines that the search variable i is not the search end variable N or more (S103: NO), as shown in FIG. 10A, the search start points SL (0) and SR (0) are obtained by the processing of S107. The processing from S101 is repeated starting from the search start points SL (1) and SR (1) corresponding to the search variable i = 1 which is separated by a predetermined interval in the direction approaching the reading end position PE in the sub scanning direction. In the present embodiment, the predetermined distance is 30 mm. The search variable N is a variable relating to the accuracy of the document determination process, and the search variable N determined by the experiment is assumed to be stored in the ROM 92. The predetermined interval is an interval automatically determined by dividing the numerical value of the search variable N by the predetermined distance.

  When it is determined that the search variable i is equal to or more than the search end variable N (S103: YES), the CPU 90 calculates a linear equation by the least square method which is a known technique for each of the searched side end edge points (S104) . The CPU 90 determines, as a document width pixel number M of the document BK, an interval parallel to the main scanning direction between two straight lines which are parallel among the straight lines calculated (S105). The CPU 90 determines the inclination θk of the left page image GL with respect to the main scanning direction calculated using the cosine theorem, which is a known technique, as the document inclination θk with respect to the main scanning direction of the spread original BK (S106).

  Specifically, the CPU 90 executes the straight line AB, the straight line BC, the straight line CD, and the straight line by the least squares method for each side end edge point corresponding to the search variable i = 0 to N shown in FIG. Each linear equation of DA is calculated (S104). The CPU 90 calculates an interval M parallel to the main scanning direction between the two straight lines AB and CD parallel to each other, and determines the calculated interval M as the document width pixel number M of the spread original BK (S105). The CPU 90 calculates cos θ k based on the interval between line segments AD, AE, and ED shown in FIG. 10A using the cosine theorem to obtain θ k, and the main scanning of the document BK with a spread of θ k The document inclination θk with respect to the direction is determined (S106).

[Reading end judgment processing]
The MFP 1 according to the present embodiment determines the end of reading by comparing the respective pixel values in the edge image data and the density image data with the threshold value by the reading end determination processing illustrated in the flowcharts of FIGS. 7 and 8. The reading of the image by the unit 4 is ended, and the rotation of the motor 59 is stopped.

  The reading end determination process in the MFP 1 will be described with reference to the flowcharts of FIGS. 7 and 8. As shown in FIG. 7, the CPU 90 turns off the edge detection flag, stores it in the RAM 93, and initializes the edge detection flag (S200). The CPU 90 initializes the sub scanning variable n and stores it in the RAM 93 (S201). The CPU 90 acquires the number of lines counted by the line counter 104 as the reference line number Lk (S202). The CPU 90 acquires the line number Lg counted by the line counter 104, and determines whether the acquired line number Lg is equal to or more than the number of lines (Lk + LN) obtained by adding the predetermined line number LN to the reference line number Lk S203). When it is determined that the acquired line number Lg is not equal to or more than the line number (Lk + LN) (S203: NO), the CPU 90 repeats the determination process of S203. Specifically, a line in which the predetermined line number LN is equal to or more than the subscanning edge judgment pixel number N1 of the edge judgment target block described later and the subscanning density judgment pixel number N2 which is the pixel number in the subscanning direction of the density judgment object range. It is assumed that the numbers are stored in the ROM 92.

  If it is determined that the acquired line number Lg is equal to or more than the line number (Lk + LN) (S203: YES), the CPU 90 determines whether the edge detection flag stored in the RAM 93 is off (S204). If it is determined that the edge detection flag is not off (S204: NO), the CPU 90 executes the processing of S301 and later in the concentration determination processing described later shown in FIG. If it is determined that the edge detection flag is off (S204: YES), the CPU 90 initializes the main scanning variable m and stores it in the RAM 93 (S205). As shown in FIG. 11A, in the edge image data 110 stored in the RAM 93, the CPU 90 follows the direction from the pixel P (m, n) which is the edge determination target block to the reading end position PE in the sub scanning direction. Edge pixel values up to the pixel P (m, n + N1) separated by the sub-scanning edge determination pixel count N1 are acquired (S206). The CPU 90 determines whether or not the edge pixel value from the acquired pixel P (m, n) to the pixel P (m, n + N1) is equal to or more than the edge threshold Eh (S207). When it is determined that the edge pixel values from the acquired pixel P (m, n) to the pixel P (m, n + N1) are not each equal to or more than the edge threshold Eh (S207: NO), the CPU 90 performs subscanning to the subscanning variable n It is determined whether a variable (n + N1) obtained by adding the edge determination pixel number N1 is equal to or more than a predetermined line number LN (S217). If it is determined that the variable (n + N1) is not equal to or more than the predetermined line number LN (S217: NO), the CPU 90 initializes the main scanning variable m and adds a predetermined constant ns to the subscanning variable n. , Sub-scanning variable n (S218), and the processing after S206 is repeated. When it is determined that the variable (n + N1) is equal to or more than the predetermined line number LN (S217: YES), the CPU 90 repeats the processing of S202 and thereafter.

  When it is determined that the edge pixel values from the acquired pixel P (m, n) to the pixel P (m, n + N1) are each equal to or greater than the edge threshold Eh (S207: YES), the CPU 90 determines that the main scanning variable m is the document width It is determined whether the number of pixels is equal to or more than M (S208). When it is determined that the main scanning variable m is not the document width pixel number M or more (S208: NO), the CPU 90 adds 1 to the main scanning variable m and substitutes it into the main scanning variable m (S216). Repeat the process. If it is determined that the main scanning variable m is equal to or more than the document width pixel number M (S208: YES), the CPU 90 turns on the edge detection flag (S209). The CPU 90 stores the number of lines counted by the line counter 104 in the RAM 93 as the number EE of trailing edge lines (S210).

  Specifically, in the case of sub-scanning edge determination pixel number N1 = 4, predetermined constant ns = 1, edge threshold value Eh = 1, document width pixel number M = 2480, and predetermined line number LN = 32, as shown in FIG. This will be described with reference to (A) and FIG. 11 (B). The CPU 90 acquires edge pixel values of the pixels P (0, 0) to P (0, 4) in the edge image data 110 shown in FIG. 11A (S206). The CPU 90 determines that the edge pixel values (= 0) of the pixels P (0, 0) to the pixels P (0, 4) are not equal to or more than the edge threshold Eh (= 1) (S207: NO). The CPU 90 determines that the variable (n + N1) (= 4) is not the predetermined line number LN (= 32) or more (S217: NO), the CPU 90 initializes the main scanning variable m, and the sub scanning variable n (= 0 1) is added and substituted for n (S218). The CPU 90 acquires edge pixel values of the pixels P (0, 1) to P (0, 5) in the edge image data 110 shown in FIG. 11B (S206). The CPU 90 determines that the edge pixel value (= 1) of the pixel P (0, 5) is equal to or greater than the edge threshold Eh (= 1) (S207: YES). The CPU 90 determines that the main scanning variable m (= 0) is not equal to or more than the document width pixel number M (= 2480) (S208: NO), adds 1 to the main scanning variable m (= 0), and performs main scanning Substituting into a variable m (S216), edge pixel values of pixels P (1,1) to P (1,5) in the edge image data 110 shown in FIG. 11B are obtained (S206). Since the edge pixel value of the pixel P (1, 5) is 1, the CPU 90 determines that it is equal to or higher than the edge threshold Eh (= 1) as in the pixel P (0, 5) (S207: YES) The processes from S208, S216, and S206 are repeated until the main scanning variable m becomes equal to 2480, which is the document width pixel number M. The edge threshold Eh is a predetermined numerical value which is greater than 0 and less than or equal to 1. The edge threshold value Eh is confirmed in advance by experiment and determined, and stored in the ROM 92.

  After executing the processing of S209, the CPU 90 executes density determination processing to be described later on the density image data of R color stored in the RAM 93 (S211), and similarly, the density image of G color stored in the RAM 93 A density determination process described later is executed on the data and the density image data of B color. (S212, S213). The CPU 90 causes the reading unit 4 to finish reading the image (S214), and causes the drive unit 5 to stop the rotation of the motor 59 (S215).

  The density determination process, which is a subroutine process of the reading end determination process in the MFP 1, will be described with reference to the flowchart of FIG. The CPU 90 initializes the main scanning variable m and substitutes the sub scanning variable n into the sub scanning reference variable Nk (S300). As the density judgment target range, the CPU 90 is separated from the pixel P (m, n) by the number N2 of sub-scanning density judgment pixels along the direction from the pixel P (m, n) to the reading end position PE in the sub-scanning direction. The density pixel values in the range up to the pixel P (M, n + N2) separated by the document width pixel number M are acquired (S301). In the density image data, the CPU 90 sets the ratio of the density pixel value equal to or less than the gray density threshold Gh to the total number of pixels in the range from the pixel P (m, n) to the pixel P (M, n + N2) It is determined whether it is Wh or more (S302).

  When it is determined that the ratio of the density pixel value which is equal to or less than the gray density threshold Gh is not equal to or more than the ratio threshold Wh with respect to the total number of pixels (S302: NO), the CPU 90 sets the subscanning density determination pixel to the subscanning variable n. It is determined whether the variable (n + N2) obtained by adding the number N2 is equal to or more than the predetermined line number LN (S304). When it is determined that the variable (n + N2) is not the predetermined line number LN or more (S304: NO), the CPU 90 substitutes a variable (n + ns) obtained by adding a predetermined constant ns to the subscanning variable n into the subscanning variable n. (S306), repeat the processing after S301. If it is determined that the variable (n + N2) is equal to or larger than the predetermined line number LN (S304: YES), the CPU 90 acquires the line number Lg counted by the line counter 104, and the acquired line number Lg is stored in the RAM 93. It is determined whether the number of pixels NSW or more is equal to or greater than the number of pixels NSW (S305). If it is determined that the acquired line number Lg is not equal to or more than the pixel number NSW stored in the RAM 93 (S305: NO), the CPU 90 repeats the process from S202 shown in FIG. When it is determined that the acquired line number Lg is equal to or more than the pixel number NSW stored in the RAM 93 (S305: YES), the CPU 90 executes the processing of S214 and later shown in FIG. When it is determined that the ratio of the density pixel value which is equal to or less than the gray density threshold Gh is equal to or higher than the ratio threshold Wh with respect to the total number of pixels (S302: YES), the CPU 90 sets the subscanning Is substituted (S303), and the concentration determination processing is ended.

  Specifically, subscanning density determination pixel count N2 = 3, document width pixel count M = 2480, predetermined constant ns = 1, gray density threshold Gh = 180, ratio threshold Wh = 30%, and predetermined line count LN = 11C and 11 for the case where the CPU 90 executes the processing of S207 (YES), S208 (YES), S209, and S210 with the sub scanning variable n = n + 1. This will be described with reference to (D). The CPU 90 performs sub-scanning along the direction from the pixel P (0, n + 1) in the density image data 111 of R color shown in FIG. 11C and the pixel P (0, n + 1) to the reading end position PE in the sub scanning direction. Pixel P (0, n + 4) separated by the scanning density determination pixel number N2, pixel P (2480, n + 1) separated by the document width pixel number M (= 2480) in the main scanning direction, and pixel P (2 The density pixel values in the density determination target range surrounded by 2480, n + 4) are respectively acquired (S301). Since the density pixel value of pixel P (0, n + 1) to pixel P (2480, n + 4) which is the density determination target range is 190 at the minimum value, the CPU 90 is a density which is less than the gray density threshold Gh (= 180). Since the percentage of pixel values is 0%, it is determined that the percentage is not equal to or greater than the percentage threshold Wh (= 30%) (S302: NO). The CPU 90 determines that the variable (n + 1 + N2) (= 4) is not greater than or equal to the predetermined line number LN (= 32) (S304: NO), and the CPU 90 adds 1 to the sub scanning variable n (= n + 1). (S306). The CPU 90 acquires density pixel values of the pixel P (0, n + 2) to the pixel P (2480, n + 5) which are the density determination target range in the density image data 111 of R color shown in FIG. . The CPU 90 determines that the density pixel values of pixel P (0, n + 2) to pixel P (2 480, n + 5) in the density determination target range have a minimum value of 180 and a gray density threshold Gh (= 180) or less. Since the percentage of is 33%, it is determined that the percentage threshold Wh (= 30%) or more (S302: YES). After executing the process of S303, the CPU 90 executes the density determination process on the G and B color density image data as described above (S212 and S213), and executes the processes of S214 and S215.

  For the gray density threshold Gh, the reading unit 4 reads the image of the right page BRA of the right page BKR of the spread original BK and the right page BRA of the right page BKR while moving to the right in the sub scanning direction shown in FIG. And will be described with reference to FIGS. 10 (B) and 10 (C). As shown in FIG. 10B, when the vertical distance Wz between the reading unit 4 and the right end portion BRA becomes equal to or more than the focal depth of the reading unit 4, the density pixel value of the image read by the reading unit 4 is It becomes a gray density pixel value. As shown in FIG. 10C, the gray density threshold Gh is a pixel value in the direction from the number EE of the trailing edge lines to the number NSW of lines in the sub scanning direction (the number NSW of lines calculated in the processing of S5). The pixel value is any one of pixel values excluding the maximum value BKG (max) and the minimum value BKG (min). The gray density threshold value Gh is set as shown in FIG. 10C, and the CPU 90 executes the above-described reading end determination processing, whereby the position of the line number NSW calculated based on the fixed size of the spread original BK is The reading of the image of the reading unit 4 can be ended with the reading end line number LE which is the number of lines close to the reading start position in the sub scanning direction, and the motor 59 can be stopped. The ratio threshold value Wh is a predetermined threshold value of 1% or more, and is confirmed in advance by experiments and determined, and stored in the ROM 92.

[Image output processing]
The image output process performed by the multifunction device 1 according to the present embodiment will be described with reference to the flowchart of FIG. 9 and FIG. In FIG. 12A, as in FIG. 10A, in the edge image data stored in the RAM 93, the spread original of the edge image in which the data of “1” is indicated by a solid line for visual explanation. FIG. 17 is a view showing a trailing edge image EG2 including only the image GR corresponding to the right page BKR of BK. For simplification of the description, the document information described in the spread document BK in the edge image data is not shown. In FIG. 12A, the outer periphery of the rear end edge image EG2 is indicated by an alternate long and short dash line. In FIG. 12A, a plurality of dotted arrows indicate search directions of rear end edge points from the search start points SP (0), SP (1)... SP (N). By the image output processing shown in the flowchart of FIG. 9, the trailing edge point of the right page image GR corresponding to the right page BKR of the spread original BK is detected in the trailing edge image EG2 shown in FIG. Images of the page image GL and the right page image GR are extracted and output to the center of the recording sheet. In the present embodiment, for simplification of the explanation, the inclination θk of the document is 0 or the CPU 90 executes the process of S214 and before the image output process, the read image GA and the trailing edge image EG2 are processed. The case where the inclination θk of the document is corrected will be described.

  Image output processing in the multifunction device 1 will be described with reference to the flowchart in FIG. The CPU 90 acquires the number of lines counted by the line counter 104, and stores it in the RAM 93 as the reading end line number LE (S400). The CPU 90 initializes the rear end variable p and stores it in the RAM 93 (S401). The CPU 90 starts searching for the rear end edge point of the right page image GR corresponding to the right page BKR of the spread original BK from the search start point corresponding to the rear end variable p in the edge image data stored in the RAM 93 (S402). The CPU 90 determines whether or not the number of pixels up to the number of lines obtained by subtracting the number of rear end edge lines EE from the number of end lines of reading LE is searched (S403). When it is determined that the number of pixels up to the number of lines obtained by subtracting the number of rear end edge lines EE from the number LE of read completion lines is not searched (S403: NO), the CPU 90 repeats the determination process of S403. When it is determined that the number of pixels up to the number of lines obtained by subtracting the number EE of the trailing edge lines from the number LE of reading completion lines is searched (S403: YES), the CPU 90 stores the position information of the retrieved trailing edge points in the RAM 93 To do (S404). The CPU 90 determines whether the rear end variable p is equal to or more than the search end variable PF (S405). If it is determined that the rear end variable p is not equal to or more than the search end variable PF (S405: NO), the CPU 90 adds 1 to the rear end variable p and substitutes it into the rear end variable p (S412). repeat.

  Specifically, as shown in FIG. 12A, the CPU 90 performs a search corresponding to the rear end variable p = 0 which is the rear end point on the read end line number LE of the rear end edge image EG2 stored in the RAM 93. The start point SP (0) is set as the search start point of the side end edge point of the right page image GR (S402). The CPU 90 searches the edge point in the trailing edge image EG2 while moving the search point in the direction approaching the reading start position PS along the sub-scanning direction (S402). If the CPU 90 determines that the search point has been moved to the line number obtained by subtracting the rear end edge line number EE from the reading end line number LE (S403: YES), the reading start position PS The position information of the closest edge point is stored in the RAM 93 as the position information of the rear end edge point EP (0) (S404). The right end portion BRA of the spread original BK is composed of a plurality of page end portions, so in the image GRA corresponding to the right end portion BRA in the rear end edge image EG2, the edge whose edge pixel value is “1” There are a plurality of pixels along the main scanning direction. Since a plurality of edge points are searched in the sub scanning direction as the edge point is searched by the processing of S402, the edge point closest to the edge pixel in the reading start position PS and the number of rear end edge lines EE is the rear end edge It will be a point. When the CPU 90 determines that the rear end variable p is not equal to or more than the search end variable PF (S405: NO), the main scanning is performed from the search start point SP (0) as shown in FIG. The processing from S403 onward is repeated with the search start point SP (1) corresponding to the search variable p = 1 which is separated from the direction search start point SP (0) by a predetermined interval as a start point. The search end variable PF is a numerical value corresponding to the document width pixel number M. The predetermined interval is an interval automatically determined by dividing the document width pixel number M by the numerical value of the search variable PF.

  If it is determined that the rear end variable p is equal to or more than the search end variable PF (S405: YES), the CPU 90 executes a search for the rear end edge points EP (0), EP (1),. A linear equation is calculated by the least squares method which is a known technique (S406). The CPU 90 re-stores the number EE of rear end edge lines stored in the RAM 93 in the RAM 93 as the number of pixels from the reading start position PS to the linear formula calculated in the sub-scanning direction (S407). As shown in FIG. 12B, the CPU 90 causes the image processing unit 94 to extract an image GK corresponding to the spread original BK from the read image GA stored in the RAM 93 (S408). As shown in FIG. 12C, the CPU 90 causes the image processing unit 94 to bring the image GK corresponding to the spread document BK extracted in the output range OA closer to the right end line number SE of the output range OA in the sub scanning direction. The image is moved by (SE-EE) / 2 in the direction, and stored in the RAM 93 (S409). The CPU 90 causes the image forming unit to output the image data in the output range OA onto a recording sheet (S410). The output range OA may be stored in the ROM 92 as an output range corresponding to any of the fixed sizes, or in the output range corresponding to the fixed size input from the user by the operation unit 7 It may be.

[Function effect]
The multi-function device 1 according to the present embodiment includes the platen glass 2 supporting the spread original BK, the reading unit 4 reading line data of the spread original BK in the main scanning direction, and the reading end position from the reading start position PS in the sub scanning direction. A driving unit 5 for moving the reading unit 4 toward the PE, an edge image generation unit 103 for performing edge enhancement processing on image data related to a line image read by the reading unit 4 to generate edge image data, and main scanning A line counter 104 that counts lines in the direction, an image forming unit 10 that outputs image data in a predetermined output range OA, and a CPU 90 are provided. The CPU 90 causes the reading unit 4 to read the line data of the spread original BK by the process of S3, determines the end of reading by the reading unit 4 by the process of S7, and processes the right page BKR of the spread original BK by the processes of S401 to S405. Is detected, and the image GK of the double-page spread original BK is moved by (SE-EE) / 2 in the subscanning direction in the output range OA by the processing of S400 and S406 to S410. Then, the image in the output range OA is output to a recording sheet by the processing of S411.

  Thus, the user can form the image of the spread original on the recording sheet by aligning the center position of the image of the spread original with the center position of the recording sheet.

[Correspondence between embodiment and invention]
The multifunction device 1 is an example of the image reading apparatus of the present invention. The CPU 90 is an example of the control unit of the present invention. The platen glass 2 is an example of the document table of the present invention. S3 to S7 are an example of the reading process of the present invention. The edge threshold Eh is an example of the first threshold of the present invention. S201 and S205 to S209 are an example of the edge determination process of the present invention. The gray density threshold Gh is an example of the second threshold of the present invention. The ratio threshold value Wh is an example of the third threshold value of the present invention. S211 to S213 and S300 to S303 are examples of the concentration determination process of the present invention. S215 is an example of the movement stop process of the present invention. S206, S207, and S216 to S218 are examples of the edge determination control process of the present invention. S301 and S304 to S306 are examples of the concentration determination control process of the present invention. The document width pixel number M is an example of the main scanning document width of the present invention. The document inclination θk is an example of the main scanning document inclination of the present invention. S100 to S107 are an example of the document determination process of the present invention. S5 is an example of the specific line determination process of the present invention. S6 is an example of the line number determination process of the present invention. The image forming unit 10 is an example of the image output unit of the present invention. S400 is an example of the reading end line storage process of the present invention. S <b> 401 to S <b> 405 and S <b> 412 are examples of the trailing edge detection process of the present invention. S406 and S407 are an example of the rear end line determination process of the present invention. S408 is an example of the image extraction process of the present invention. S409 is an example of the image output range determination process of the present invention. S410 is an example of the image output process of the present invention.

[Modification]
The present invention is not limited to the embodiments described above with reference to the drawings. For example, the present embodiment may be modified as follows.

  (1) In the present embodiment, the number of pixels in the main scanning direction of the edge determination target range is configured by the document width edge pixel number M, but the present invention is not limited to this configuration. The number of pixels in the main scanning direction of the edge determination target range may be configured with a predetermined number of pixels. Further, in the present embodiment, the number of pixels in the sub-scanning direction of the edge determination target range is configured with the number N1 of sub-scanning edge determination pixels, which is a predetermined plurality of pixels, but is not limited to this configuration. A configuration in which the number of pixels in the subscanning direction represented by M × sin θk is the number of pixels in the subscanning direction of the edge determination target range based on the document width pixel number M and the document inclination θk determined by the process of S4. It may be

  (2) In the embodiment, the edge determination target ranges P (m, n) to P (M, n + N1) are divided into edge determination target blocks, but the present invention is not limited to this configuration. The edge determination target ranges P (m, n) to P (M, n + N1) may not be divided into edge determination target blocks. In this case, the CPU 90 acquires edge pixel values in the edge determination target range P (m, n) to P (M, n + N1) in the process of S206. In the process of S207, the CPU 90 determines whether the edge pixel value acquired in the process of S206 is one of a plurality of edge pixel values in the sub-scanning direction being equal to or greater than the edge threshold Eh. This is performed for each of a plurality of pixels in the main scanning direction of the range.

  (3) In the present embodiment, the number of pixels in the main scanning direction of the density determination target range is configured by the document width edge pixel number M, but the present invention is not limited to this configuration. The number of pixels in the main scanning direction of the density determination target range may be configured with a predetermined number of pixels. Further, in the present embodiment, the number of pixels in the sub-scanning direction of the density determination target range is configured with the number N2 of sub-scanning density determination pixels, which is a predetermined plurality of pixels, but is not limited to this configuration. Based on the inclination θw of the right end portion BRA of the book document BK with respect to the document placement surface 2a shown in FIG. 10B and the depth of focus Wk of the reading unit 4, the distance in the sub scanning direction calculated by Wk / tan θw The corresponding pixel number may be set to the sub-scanning density determination pixel number N2. As a result, after the edge detection flag is turned on by the process of S207 and S208 by the CPU 90 (S207: YES, S208: YES, S209), the ratio of the number of pixels having the gray density threshold or less in the density determination target range is As a result, the CPU 90 can execute the processing of S214 and S215 early.

  (4) In the present embodiment, the resolution conversion unit 101 is included in the image processing unit 94, but the present invention is not limited to this configuration. The line data of each of the RGB colors read by the reading unit 4 may be connected to the color conversion unit 102 without being connected to the resolution conversion unit 101, and may be output and stored in the RAM 93 as density image data. .

  (5) In the present embodiment, in the density determination target range, the ratio to the total number of pixels of the density determination target range which is the density pixel value equal to or less than the gray density threshold is the density relative to the density pixel value equal to or less than the gray density threshold Although the configuration is such that calculation is performed by dividing the total number of pixels in the determination target range, the present invention is not limited to this configuration. The ratio of the density determination target range in which the density pixel value is equal to or less than the gray density threshold to the total number of pixels may be set as the number of density pixels in which the density pixel value is equal to or less than the gray density threshold.

  (6) Although the predetermined variable ns is set to 1 in the present embodiment, the present invention is not limited to this structure. The predetermined variable ns may be a numerical value which is 2 or more and less than the predetermined line number LN.

  (7) Although this embodiment is configured to execute the processes of S5 and S6 shown in FIG. 5, the present invention is not limited to this configuration. The CPU 90 may be configured to execute the process of S7 after performing the process of S4.

  (8) In the present embodiment, in the process of S5, the CPU 90 calculates the number of pixels LSW obtained by subtracting the number of pixels RSW corresponding to the short side width of the right edge portion BRA of the spread document BK from the number of pixels 2SW. Although it is set as a structure which determines as a judgment start line number, it is not limited to this structure. The number of pixels RSW corresponding to the short side width of the right end portion BRA of the spread original BK is subtracted from the number of pixels 2SW, and the predetermined number of pixels is further subtracted to calculate the number of pixels LSW. It may be. The predetermined number of pixels is the number of pixels for bringing the determination start line number LSW closer to the reading start position PS in the sub scanning direction from the right end portion BRA of the double-page spread original BK. The predetermined number of pixels may be the number of pixels in the sub-scanning direction represented by M × sin θk, based on the document width pixel number M and the document inclination θk determined in the process of S4. As a result, even when the double-page spread original BK is inclined with respect to the main scanning direction by the original inclination θk, it is possible to improve the detection accuracy of the edge pixel value which is equal to or higher than the edge threshold Eh.

  (9) In the present embodiment, the line image data of each of the RGB colors is stored in the RAM 93 as density image data after the resolution conversion unit 101 and before the color conversion unit 102. However, the present invention is limited to this configuration. I will not. The data of the luminance value of each pixel may be stored as the density image data in the RAM 93 after the color conversion unit 102 and before the edge image generation unit 103. In this case, the CPU 90 may execute the process of S211 on density image data configured of data of the luminance value of each pixel, and may not execute the processes of S212 and S213.

  (10) In the present embodiment, the processing of S214 is performed, but the present invention is not limited to this. After executing the processing of S213, the CPU 90 may execute the processing of S215 without executing the processing of S214. In this case, the CPU 90 executes the process of S <b> 8 and then executes the process of S <b> 214, and executes the process of S <b> 9 after the process of S <b> 214.

2 ... platen glass, 4 ... reading unit, 5 ... driving unit, 103 ... edge image generating unit,
90 CPU, 1 multifunction machine

Claims (8)

A manuscript support for supporting the manuscript,
A reading unit that reads a line image of a document in the main scanning direction;
A driving unit for moving the reading unit from a reading start position toward a reading end position in a sub-scanning direction orthogonal to the main scanning direction;
An edge image generation unit that performs edge enhancement processing on image data relating to the line image read by the reading unit to generate edge image data;
And a control unit,
The control unit
Reading processing for causing the reading unit to read the line image while moving the reading unit from the reading start position in the sub scanning direction to the reading end position in the driving unit;
An edge pixel value of an edge determination target range including a plurality of pixels in the sub scanning direction and a plurality of pixels in the main scanning direction is acquired from the edge image data generated by the edge image generation unit, and the acquired edge With respect to the edge pixel value in the determination target range, it is determined whether or not any of the edge pixel values of the plurality of pixels along the sub scanning direction is equal to or greater than a first threshold, along the main scanning direction. Edge determination processing performed for each of the plurality of pixels;
In the edge determination processing, it is determined that, in all the plurality of pixels along the main scanning direction, any of the edge pixel values of the plurality of pixels along the sub scanning direction is equal to or greater than a first threshold In this case, from the image data closer to the reading end position in the sub scanning direction than the position corresponding to the edge determination target range in the image data, a plurality of pixels in the sub scanning direction and a plurality of pixels in the main scanning direction The pixel value of the density determination target range consisting of is obtained, and the obtained pixel value of the density determination target range becomes a pixel value equal to or less than the second threshold except for the minimum value and the maximum value that can be taken of the pixel value. Density determination processing for determining whether a ratio corresponding to the total number of pixels in the density determination target range is equal to or greater than a third threshold;
Movement stop processing for causing the drive unit to stop the reading unit moving in the sub scanning direction when it is determined by the density determination processing that the ratio is equal to or more than the third threshold;
Perform an image reader. In the image reading apparatus according to claim 1,
The control unit
According to the edge determination processing, in at least one or more pixels among the plurality of pixels along the main scanning direction, all the edge pixel values respectively related to all the plurality of pixels along the sub scanning direction If it is determined that the value is less than one threshold, the edge determination range is determined as a new edge determination range, which is a predetermined number of pixels away from the edge determination range toward the reading end position in the sub scanning direction. Edge determination control processing that executes the processing again;
When it is determined by the density determination process that the ratio is less than the third threshold, a predetermined number of pixels are separated from the position corresponding to the edge determination target range toward the reading end position in the sub scanning direction An image reading apparatus that executes density determination control processing that executes the density determination processing again as a position corresponding to a new edge determination target range; In the image reading apparatus according to claim 2,
The control unit
After the start of the reading process, an original determination process is performed to determine the main scanning original width of the original and the main scanning inclination of the original by detecting the leading edge or the side edge of the original in the edge image data. ,
The edge judgment target range is
The control unit comprises a plurality of pixels in the main scanning direction determined based on the main scanning document width, and a plurality of pixels in the sub scanning direction determined based on the main scanning document width and the main scanning document inclination. Range,
The new edge judgment target range is
An image reading apparatus, which is an edge determination target range separated from the edge determination target range by one pixel toward the reading end position in the sub scanning direction. In the image reading apparatus according to claim 2,
The concentration judgment target range is
A plurality of pixels and the main in the sub-scanning direction predetermined based on the inclination of the side end of the document in the sub-scanning direction toward the reading end position with respect to the document table and the focal depth of the reading unit An image reading apparatus which is a range consisting of a plurality of pixels in a scanning direction. In the image reading apparatus according to claim 4,
The edge judgment target range is
In the edge analysis image data, it is constituted by pixel data including the specific pixel data which is one pixel data in the main scanning direction as a reference to the range of the edge sub-scanning width in the moving direction from the specific pixel data. The edge determination target block is a range consisting of a plurality of the edge determination target blocks configured along the main scanning direction by the number of pixel data in the range of the main scanning document width from the specific pixel data as one unit ,
The edge determination process is
The edge pixel data is acquired for each of the edge determination target blocks, and all the edge determination target blocks have the acquired first edge threshold data or more for each of the edge determination target blocks. Judge against
The edge determination control process is
When it is determined that the acquired edge pixel data does not exist in the one edge determination target block among all the edge determination target blocks as the result of the edge determination processing, the specific pixel data is not present An image reading apparatus that executes again the edge determination processing as new specified pixel data with pixel data separated by a predetermined number of pixel data in the movement direction. In the image reading apparatus according to claim 2,
The reading unit is
Reading an image of a document for each line in the main scanning direction;
The edge image generation unit
Edge enhancement processing is performed on the analysis image data for each line in the main scanning direction, and pixels for which the pixel value of each pixel is equal to or more than a predetermined threshold in each pixel in the main scanning direction are edge pixels Generate edge image data as
A line counter for counting the number of lines in the main scanning direction;
The control unit
A specific line determination process of determining the number of lines of a specific line in the main scanning direction based on the main scanning document width determined by the original determination process;
Performing a line number determination process of determining whether the number of lines in the main scanning direction counted by the line counter is equal to the number of lines of the particular line;
When it is determined that the counted number of lines in the main scanning direction is equal to the number of lines of the specific line as a result of the line number determination process, the edge acquisition determination process is executed based on a specific pixel in the specific line. Image reader. In the image reading apparatus according to claim 6,
An image output unit for outputting image data in a predetermined output range;
The control unit
Reading end line storing processing for storing the line number of reading ending lines counted by the line counter after execution of the reading end processing, and rear end edge detection processing for detecting the rear end edge of the document in the edge image data And, on the basis of the rear end edge, the rear end line determination processing for determining the number of lines of the rear end edge based on the detected rear end edge of the document and the number of lines of the reading completion line. And an output range determining process for determining the output range based on the main scanning document width based on an image extracting process for extracting image data read by a copy unit, and based on the number of lines of the specific line and the rear end edge. An image output process of arranging the extracted read image data within the determined output range. An original support plate for supporting an original, a reading unit for reading a line image of the original in the main scanning direction, and the reading unit from the reading start position to the reading end position in the sub scanning direction orthogonal to the main scanning direction An image to be executed by a control unit of an image reading apparatus including a driving unit, and an edge image generation unit that performs edge enhancement processing on image data related to the line image read by the reading unit and generates edge image data A reading program,
Reading processing for causing the reading unit to read the line image while moving the reading unit from the reading start position in the sub scanning direction to the reading end position in the driving unit;
An edge pixel value of an edge determination target range including a plurality of pixels in the sub scanning direction and a plurality of pixels in the main scanning direction is acquired from the edge image data generated by the edge image generation unit, and the acquired edge With respect to the edge pixel value in the determination target range, it is determined whether or not any of the edge pixel values of the plurality of pixels along the sub scanning direction is equal to or greater than a first threshold, along the main scanning direction. Edge determination processing performed for each of the plurality of pixels;
In the edge determination processing, it is determined that, in all the plurality of pixels along the main scanning direction, any of the edge pixel values of the plurality of pixels along the sub scanning direction is equal to or greater than a first threshold In this case, from the image data closer to the reading end position in the sub scanning direction than the position corresponding to the edge determination target range in the image data, a plurality of pixels in the sub scanning direction and a plurality of pixels in the main scanning direction The pixel value of the density determination target range consisting of is obtained, and the obtained pixel value of the density determination target range becomes a pixel value equal to or less than the second threshold except for the minimum value and the maximum value that can be taken of the pixel value. Density determination processing for determining whether a ratio corresponding to the total number of pixels in the density determination target range is equal to or greater than a third threshold;
Movement stop processing for causing the drive unit to stop the reading unit moving in the sub scanning direction when it is determined by the density determination processing that the ratio is equal to or more than the third threshold;
An image reading program that executes

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