JP6447006B2 - Image processing apparatus, image reading apparatus, image processing method, and image processing program - Google Patents

Description

The present invention relates to an image processing apparatus, image reading apparatus, an image processing method and image processing program, in particular, an image processing device for detecting an inclination of a document, the image reading apparatus, an image processing method and image processing program.

  In recent years, along with the digitization of information, it has been performed to read an image of a document with an image reading device such as a scanner, acquire image data, and manage the digital image data.

  However, when reading image data of a document with an image reading device, if an automatic document feeder is attached to the image reading device and a plurality of documents are sequentially conveyed and read, the read image may be tilted due to document skew. is there.

  Therefore, conventionally, the inclination of the document conveyed by the automatic document conveying device is mechanically corrected.

  However, when a mechanism for mechanically correcting the inclination of a document is incorporated in an automatic document feeder, the mechanical noise is large and it has become impossible to satisfy the quietness required for recent devices.

  Therefore, in recent years, it has been performed to detect the inclination of the read image data and correct the inclination by image processing.

  Conventionally, a detection unit that detects the size of the document, an image reading unit that irradiates light to the reading position of the document and reads a read image from the reflected light, and a range based on the size of the document read by the detection unit The boundary between the document image corresponding to the document and the background image corresponding to the area other than the document is read from the scanned image, and the boundary between the boundary and the document transport direction is An image reading apparatus having an inclination correction unit for correcting the inclination of the original image has been proposed (see Patent Document 1).

  That is, this conventional technique detects the document size, reads the boundary between the document image corresponding to the document and the background image corresponding to the area other than the document from the scanned image within the document size range, Is detected.

  However, in the above prior art, since the original size is detected by detecting the original size, it is necessary to improve the accuracy of detecting the original inclination angle.

  In other words, if the document size is detected incorrectly, or a detection error in detecting the boundary between the document image and the background image with respect to a region other than the document due to factors other than detection dust or vertical stripes cannot be prevented, the document tilt angle There was a risk that a detection error would occur.

  Accordingly, an object of the present invention is to accurately determine the document inclination.

In order to achieve the above object, an image processing apparatus according to claim 1 is based on an image reading unit that reads an image of a conveyed document and outputs image data, and image data output by the image reading unit. An electronic end detecting means for detecting a leading end in the transport direction of the document to be transported as an electronic end, and an optical type for optically detecting a leading end in the transport direction of the transported document as an optical end. An edge detection means; an electronic inclination extraction means for extracting the inclination of the leading edge of the document in the transport direction as an electronic inclination based on the electronic edge; and an optical edge of the original based on the optical edge. An optical inclination extraction means for extracting the inclination of the leading end in the conveying direction as an optical inclination; and a final inclination extraction means for extracting the final inclination of the document from the electronic inclination and the optical inclination, and the final inclination. extraction means The electronic inclination, it is determined whether within a predetermined determination threshold value with respect to the optical slope, when present in said determination threshold, and extracts the final slope on the basis of the electronic formula inclination, If it is outside the determination threshold, the final inclination is extracted based on the optical inclination .

  According to the present invention, it is possible to accurately determine the document inclination.

1 is a schematic front view of an image reading unit of a color composite apparatus to which an embodiment of the present invention is applied. Front schematic enlarged view of the SDF unit. Explanatory drawing of the arrangement position of a photosensor. Explanatory drawing of the subscanning direction mounting accuracy of a photosensor. Explanatory drawing of the detection accuracy in the subscanning direction of a photosensor. The front schematic enlarged view of the scanning optical system of an image reading part. The principal part block block diagram of a color compound apparatus. FIG. 3 is a block configuration diagram of a read signal processing unit. FIG. 3 is a detailed block diagram of a read signal processing unit. The functional block block diagram of an image process part. Explanatory drawing of the time difference calculation process in the detection signal of a photosensor. The figure which shows the relationship between the image area in a buffer memory, and original image data. Explanatory drawing of the document edge part detection process based on edge extraction. Explanatory drawing of the document edge part detection process based on a brightness | luminance. Explanatory drawing of the document edge part detection process based on a color difference. Explanatory drawing of an image data inclination detection and correction process. 6 is a flowchart illustrating document skew detection processing. 10 is a flowchart showing secondary document skew calculation processing.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  1 to 18 are diagrams showing an embodiment of an image processing apparatus, an image reading apparatus, an image processing method, and an image processing program according to the present invention. FIG. 1 is a front schematic configuration diagram of an image reading unit 10 of a color composite apparatus 1 to which an embodiment of an image processing apparatus, an image reading apparatus, an image processing method, and an image processing program of the present invention is applied.

  In FIG. 1, an image reading unit (image reading apparatus) 10 is provided with a document reading table (document table) 12 on an upper portion of a casing 11. The document reading table 12 is usually provided with a contact glass. ing. An openable / closable document pressing plate 13 is provided on the upper portion of the document reading table 12, and the document pressing plate 13 is configured to bring the document G set on the document reading table 12 into close contact with the contact glass of the document reading table 12. Press down on.

  A document transport unit 14 is disposed on the upper right side of the housing 11 of FIG. 1, and the document transport unit 14 includes an SDF (sheet through document feeder) unit 15 and a document tray 16. A document conveying stepping motor 17 is provided in the SDF unit 15, and a plurality of documents G are stacked on the document tray 16 with the reading surface facing up.

  As shown in FIG. 2, the document conveying unit 14 rotates a separation roller 18 and a conveying roller 19 disposed in the SDF unit 15 by a document conveying stepping motor 17. The SDF unit 15 separates the originals G on the original tray 16 one by one by a rotationally driven separation roller 18, and passes through the original conveyance path in the SDF unit 15 by a conveyance roller 19, thereby reading the original reading table. 12 is further conveyed onto a paper discharge tray (not shown). The SDF unit 15 is provided with a CIS (Contact Image Sensor) 15a, a pair of photo sensors 15b, a white plate 15c, and the like along the document conveyance path.

  The CIS 15a reads an image on the back side of the document G conveyed on the document conveyance path.

  The photosensors 15b are arranged in a pair at a predetermined distance in the main scanning direction (a direction orthogonal to the document conveyance direction), and each detects the leading edge of the document G conveyed on the document conveyance path.

  For example, as shown in FIG. 3, the pair of photosensors 15b are arranged at a distance so as to be able to detect two leading edges of a document G having a minimum width size that can be processed by the color composite apparatus 1. ing. In the case of FIG. 3, the case where the B6 document has the SEF (Short Edge Feed) direction as the minimum width size is shown. Specifically, for example, the photosensor 15b is located at a position 10 mm from the reading origin of the original G in the main scanning direction (hereinafter, referred to as a first detection position P1) and a position at an interval of 100 mm from the first detection position P1. (Hereinafter, referred to as a second detection position P2).

  When the photosensor 15b is arranged and mounted as shown in FIG. 3, the mounting position accuracy is usually ± 1.5 mm with respect to the sub-scanning direction as shown in FIG. is there. Therefore, the maximum error of the mounting position in the two photosensors 15b is 3 mm / 100 mm. However, this error due to the mounting position accuracy can be corrected by adjusting the signal generation timing of the photo sensor 15b, and by calibrating each unit at the time of shipment of the color composite apparatus 1 from the factory, The error can be set to “0”.

  The photosensor 15b includes an error in its detection accuracy. For example, as shown in FIG. 5, the photosensor 15b has a detection accuracy when the document edge passes the target detection position even when the sensor mounting error is adjusted to “0” as described above. The maximum error is about 0.6mm.

  Therefore, the absolute value of the inclination of the original G by the two photosensors 15b includes an error of maximum | 1.2 mm / 100 mm |. For example, even if the document G passes through the photo sensor 15b with no tilt, the detection result of the photo sensor 15b may be a detection result that the document G is tilted.

  Assuming that the skew standard of the SDF unit 15 is | ± 0.75 mm / 100 mm |, the detection error of the photosensor 15b greatly exceeds this standard as follows.

Tilt detection error | ± 1.2mm / 100mm |
> Skew standard | ± 0.75mm / 100mm |
Therefore, the inclination of the original G cannot be detected with high accuracy by using the photosensor 15b alone. Although the detection accuracy of the document edge by the photosensor method is not high, the detection of the edge portion is not greatly mistaken depending on the image characteristics of the document G, as compared with the electronic method by image processing described later. .

  The white plate 15 c is disposed at a position in the SDF unit 15 corresponding to the SDF window 15 d formed at a position facing the document reading table 12 of the SDF unit 15. The white plate 15c is read when detecting whether dust or the like is attached to the optical path through the SDF window 15d and the transmission glass 15e, in particular, the transparent glass 15e. That is, when reading the original G using the SDF unit 15, the color composite apparatus 1 reads the original G with the position of the transparent glass 15e as a fixed original reading position, and the dust on the optical path at the time of reading is read. The white plate 15c is used to detect the presence / absence or the like.

  Further, the document transport unit 14 is provided with a white reference plate 20 for shading correction at the end of the document reading table 12 on the SDF unit 15 side. The document transport unit 14 is integrated with the document pressing plate 13, and when the document pressing plate 13 is opened, the document transport unit 14 is also opened and closed together.

  In FIG. 1 again, inside the housing 11, a scanning optical system (image) comprising a first traveling body 21, a second traveling body 22, a lens 23, a CCD (Charge Coupled Device) 24, a traveling body stepping motor 25, and the like. Reading means) 26, the first traveling body 21 is mounted with a light source 21a and a mirror 21b, and the second traveling body 22 is mounted with mirrors 22a and 22b.

  The scanning optical system 26 moves the first traveling body 21 and the second traveling body 22 in the horizontal direction (sub-scanning direction) by the traveling body stepping motor 25. The scanning optical system 26 irradiates light from the light source 21 a on the first traveling body 21, for example, a fluorescent lamp, to the original G placed on the original reading table 12, and reflects the light reflected by the original G. The reflected light is reflected in the direction of the second traveling body 22 by the mirror 21 b on the first traveling body 21. The scanning optical system 26 sequentially reflects the light incident from the first traveling body 21 by the mirror 22 a and the mirror 22 b on the second traveling body 22 and emits the light in the direction of the lens 23. The scanning optical system 26 condenses and irradiates the light incident from the second traveling body 22 on the CCD 24 with the lens 23. The CCD 24 has one line of CCD elements arranged in a line in the main scanning direction as a plurality of photoelectric conversion elements in one dimension, and photoelectrically converts incident light incident from the lens 23 to obtain analog image data ( Image signal). Further, the scanning optical system 26 irradiates the white reference plate 20 with light, and the reflected light from the white reference plate 20 enters the CCD 24 in the same manner as described above, and outputs from the CCD 24 as reference data for shading correction.

  The image reading unit 10 has a book mode and an SDF mode as document reading modes. In the book mode, as shown in FIG. 6, the image of the document G placed on the document reading table 12 with the document pressing plate 13 opened is read while moving the first traveling body 21 and the second traveling body 22. Mode. In the SDF mode, as shown in FIG. 2, the image of the document G conveyed using the SDF unit 15 of the document conveying unit 14 is read in a state where the first traveling body 21 and the second traveling body 22 are stationary. It is.

  In the book mode, as shown in FIG. 6, the image reading unit 10 opens the document pressing plate 13 and sets the document G on the document reading table 12. The plate 20 is read to obtain reference data for shading correction. Thereafter, the image reading unit 10 drives the traveling body stepping motor 25 to move the first traveling body 21 and the second traveling body 22 in the sub-scanning direction with the optical path length from the document G to the CCD 24 being constant. Then, after detecting the document size, the image of the document G on the document reading table 12 is read.

  In the SDF mode, as shown in FIG. 2, when a plurality of documents G are set on the document tray 16, the image reading unit 10 first turns on the light source 21 a and turns on the white reference plate 20. After reading, the document conveying stepping motor 17 is driven. The image reading unit 10 moves the first traveling body 21 to the reading position of the SDF window 15d and stops it. Next, the image reading unit 10 drives the document conveyance stepping motor 17 to separate the documents G set on the document tray 16 one by one by the separation roller 18 and conveys the document G by the conveyance roller 19, and by the CIS 15 a. The back side image of the original G is read. The image reading unit 10 conveys the original G from which the back side has been read to the position of the SDF window 15 d that is a predetermined reading position of the first traveling body 21. The image reading unit 10 conveys the document G at a constant speed and stops the first traveling body 21 and the second traveling body 22 at the reading position from the light source 21a on the first traveling body 21 through the SDF window 15d. Light is applied to the conveyed document G. The image reading unit 10 reflects the reflected light reflected by the original G again through the SDF window 15d by the mirror 21b and the mirrors 22a and 22b on the second traveling body 22, and enters the CCD 24 through the lens 23. Photoelectric conversion is performed by the CCD 24 to read an image on the surface of the original G.

  The color composite apparatus 1 is configured as a circuit block as shown in FIG. 7, and includes a CPU (Central Processing Unit) 31, a memory 32, a memory controller 33, a read signal processing unit 34, an image processing unit 35, and a write signal processing unit. 36, LD (Laser Diode) 37, LD driving unit 38, CIS 15a, CCD 24, CCD driving unit 39, light source 21a, light source driver 40, document conveying stepping motor 17 for document conveyance, document conveying motor A driver 41, a traveling body stepping motor 25 for driving the traveling body, a traveling body motor driver 42, a buffer memory 43, a buffer memory controller 44, and the like are provided.

  The memory 32 stores various programs such as a basic processing program as the image reading unit 10 and the image processing program of the present invention, and various data necessary for executing these various programs. The memory 32 is used as a work memory for the CPU 31.

  The CPU 31 uses the memory 32 as a work memory based on a program in the memory 32, controls each part of the color composite device 1 to execute processing as the color composite device 1, and performs image processing of the present invention. Run the method.

  The light source 21a is controlled to be turned on / off by the light source driver 40 under the control of the CPU 31, and the CCD 24 is driven by the CCD drive unit 39 under the control of the CPU 31 to read the photoelectrically converted image data into the read signal processing unit 34. Output to.

  The document conveying stepping motor 17 is driven by the document conveying motor driver 41 under the control of the CPU 31, and the traveling body stepping motor 25 is driven by the traveling body motor driver 42 under the control of the CPU 31.

  As shown in FIG. 8, the read signal processing unit 34 includes an analog video processing unit 51 and a shading correction processing unit 52.

  An analog color image signal (analog read data) output from the CCD 24 is input to the analog video processing unit 51. The analog video processing unit 51 digitally converts an analog color image signal and outputs the digital color image data to the shading correction processing unit 52 as digital color image data (digital read data).

  The shading correction processing unit 52 stores the color image data when the white reference plate 20 is read as reference data for shading correction in a line buffer 52c (see FIG. 9) configured by an internal RAM or the like. The shading correction processing unit 52 performs shading correction on the digital color image data digitally converted by the analog video processing unit 51 when the original G is read based on the reference data. The shading correction processing unit 52 stores the digital color image data after the shading correction in the buffer memory 43 through the buffer memory controller 44.

  The buffer memory controller 44 controls storage and reading of data to and from the buffer memory 43, and for example, a RAM or the like is used as the buffer memory 43.

  The buffer memory controller 44 receives the digital color image data from the read signal processing unit 34 and the image data on the back side of the document G from the CIS 15 a at the same time, and stores the image data for two pages in the buffer memory 43. .

  The buffer memory controller 44 alternately outputs the image data of the front surface of the document G from the CCD 24 stored in the buffer memory 43 and the image data of the back surface from the CIS 15 a to the image processing unit 35 as one page of image data.

  The image processing unit 35 performs various types of image processing for each page of image data sent from the buffer memory controller 44 and temporarily stores the image data after image processing in the memory 32 via the memory controller 33. The data is output to the write signal processing unit 36.

  The analog video processing unit 51 and the shading correction processing unit 52 of the read signal processing unit 34 are configured in detail as shown in FIG.

  That is, as shown in FIG. 9, the analog video processing unit 51 includes a preamplifier circuit 51a, a variable amplifier circuit 51b, an A / D converter 51c, and the like. The shading correction processing unit 52 includes a black arithmetic circuit 52a, a shading correction arithmetic circuit 52b, a line buffer 52c, and the like.

  The image reading unit 10 focuses the reflected light of the reading light irradiated from the light source 21 a onto the original G on the original reading table 12 through the white reference plate 20 and is focused on the CCD 24 by the lens 23 to form an image. In FIG. 9, a mirror for folding the reflected light is omitted for the sake of simplicity. The white reference plate 20 plays a role of adjusting the amount of light so as to eliminate the difference in the amount of reflected light between the central portion and the end portion of the CCD 24. That is, in the shading calculation process, if there is an excessive difference in the amount of reflected light between the central portion and the end portion of the CCD 24, only a calculation result including a large amount of distortion can be obtained. After that, shading calculation processing is performed.

  The analog video processing unit 51 amplifies the analog color image signal input from the CCD 24 by the preamplifier circuit 51a and the variable amplifier circuit 51b, and inputs the amplified signal to the A / D converter 51c. The analog video processing unit 51 digitally converts the amplified color image signal by the A / D conversion unit 51c and outputs the digital color image data to the black arithmetic circuit 52a of the shading correction processing unit 52.

  The black arithmetic circuit 52a reduces the variation in the black level (electric signal when the amount of light is small) between the chips of the CCD 24 and between the pixels of the digital color image data from the analog video processing unit 51, so that the black portion of the image. To prevent streaks and unevenness. The black arithmetic circuit 52a outputs the color image data subjected to the arithmetic processing to the shading correction arithmetic circuit 52b. The shading correction arithmetic circuit 52b performs shading correction for correcting sensitivity variations of the irradiation system, the optical system, and the CCD 24 based on the reference data held in the line buffer 52c, and stores the digital color image data in the buffer memory 43. .

  The CPU 31 sends the color image data stored in the buffer memory 43 to the image processing unit 35 via the buffer memory controller 44, and the image processing unit 35 uses the memory 32 to perform tilt correction and other necessary corrections. Perform image processing.

   The image processing unit 35 performs various image processing on the image data from the buffer memory 43 under the control of the CPU 31 and outputs the processed image data to the write signal processing unit 36. In particular, the image processing unit 35 executes image processing for detecting and correcting the document inclination under the control of the CPU 31. That is, the CPU 31 uses the image data of the original G stored in the buffer memory 43 and the detection result of the photosensor 15b based on the image processing program of the present invention in the memory 32 to accurately determine the inclination of the original G. The image processing to detect and correct is executed. Accordingly, the CPU 31, the memory 32, the memory controller 33, and the image processing unit 35 function as an image processing device 50 as a whole.

  The image processing unit 35 is constructed by an ASIC (Application Specific Integrated Circuit) or the like, but a functional block as shown in FIG. 10 is constructed by introducing the image processing program of the present invention. That is, the image processing unit 35 includes a detection time difference calculation unit 61, a sub-scanning distance generation unit 62, an optical primary document inclination calculation unit 63, detection data generation units 64a, 64b, and 64c, and an electronic primary document inclination calculation unit. 65a, 65b, 65c, a secondary document inclination calculation unit 66, an inclination correction processing unit 67, and the like are constructed.

  The detection time difference calculation unit 61 receives the detection signal at the leading edge of the document from the two photosensors 15 b, calculates the time difference Δt between these two detection signals, and outputs it to the sub-scanning distance generation unit 62. The two photosensors 15b each output a detection signal to the CPU 31 at the timing when the leading edge of the document G passes, and the CPU 31 outputs the detection signal to the image processing unit 15b. In this embodiment, the photosensor 15b outputs a detection signal to the CPU 31, but may output it directly to the image processing unit 15b.

  The detection signal from the photosensor 15b is generated independently at each of the first detection position P1 and the second detection position P2 shown in FIG. Now, as shown in FIG. 11, the detection time difference calculation unit 61 operates with a clock CLK having a frequency of 20 MHz, detects the presence or absence of the detection signals S1 and S2 from the photosensor 15b, and from one of the detection signals S1 and S2. A time difference Δt between the other detection signals S1 and S2 is calculated. The detection signals S1 and S2 are low active, the detection signal S1 is a signal from the photosensor 15b at the first detection position P1, and the detection signal S2 is a signal from the photosensor 15b at the second detection position P2. . Now, it is assumed that the conveyance speed V of the original G is 200 mm / s. The detection time difference calculation unit 61 starts counting by the clock counter when one of the detection signals S1 and S2 is asserted, and stops counting when the other detection signals S1 and S2 are asserted. Assuming that the counter value is 61500, the detection time difference calculation unit 61 calculates the time difference Δt according to the following equation (1).

Time difference Δt = 61500 / (20 × 1000000) = − 3.075 msec (1)
In FIG. 11, the minus sign is attached in Expression (1). In FIG. 11, the photosensor 15 b at the first detection position is asserted first, and the photosensor 15 b at the second detection position is asserted later. It corresponds to that. Therefore, when the photosensor 15b at the second detection position is asserted first and the photosensor 15b at the first detection position is asserted later, the sign of the time difference Δt is (+).

  Based on the time difference Δt calculated by the detection time difference calculation unit 61, the sub-scanning distance generation unit 62 extends from the leading edge position of the document G detected by one photosensor 15b to the leading edge position of the document G detected by the other photosensor 15b. Is calculated by the following equation (2).

Δy [mm] = V [mm / s] × Δt [s] (2)
In FIG. 11, when the distance in the sub-scanning direction of the first detection position P1 is applied to the expression (2) with the second detection position P2 as a reference, the distance Δy can be calculated as in the following expression. it can.

Δy = V × Δt = 200 [mm / s] × (−0.003075) = − 0.615 [mm]
The sub-scanning distance generation unit 62 outputs the calculated distance Δy to the optical primary document inclination calculation unit 63. Therefore, the photosensor 15b, the detection time difference calculation unit 61, and the sub-scanning distance generation unit 62 function as an optical end detection unit as a whole.

  The optical primary document inclination calculation unit (optical inclination extraction means) 63 determines the inclination d0 of the original G based on the distance Δy calculated by the sub-scanning distance generation unit 62 (hereinafter referred to as an optical inclination d0 as appropriate). Is calculated (extracted) by the following equation (3).

d0 = Δy / Δx (3)
Here, Δx is the distance between the two photosensors 15b, that is, the distance between the first detection position P1 and the second detection position P2. When the above example is applied to this equation (3), the following equation is obtained, which is about −0.352 degrees.

d0 = −0.615 / 100 = arctan (−0.615 / 100) = about −0.352 degrees The optical primary document inclination calculation unit 63 uses the calculated optical inclination d0 as the secondary document inclination calculation unit. 66.

  On the other hand, the detection data generation units 64 a, 64 b, 64 c output image data for detecting the inclination among the image data output from the CCD 24 and processed by the read signal processing unit 34 and stored in the buffer memory 43. Acquired at a predetermined timing. The image data for tilt detection is not necessarily image data of the entire document G. For example, image data of only the front end portion necessary for tilt detection with hatched portions (range from C to D) in FIG. It's okay. That is, from the leading edge address of the buffer memory 43 to the address where the image data of the image area including a predetermined amount of the leading edge portion of the document G is set as the detection target image region Gr, the image data of the detection target image region Gr is inclined to the document G It is set as detection target image data for detecting.

  The detection data generation units 64a, 64b, and 64c perform appropriate image processing on the detection target image data, and the subsequent electronic primary document inclination calculation units 65a, 65b, and 65c calculate the inclination of the document G, respectively. Generate the type of data used for. Therefore, the detection data generation units 64a, 64b, and 64c function as electronic end detection means.

  The electronic primary document inclination calculation units 65a, 65b, and 65c may use appropriate types of data as long as the types of data can accurately detect the leading edge of the document G using image data that has undergone image processing. Can be used. In this embodiment, the electronic primary document inclination calculation unit 65a receives edge detection data, the electronic primary document inclination calculation unit 65b brightness data, and the electronic primary document inclination calculation unit 65c outputs color difference data. In the following description, it is assumed that the document inclination is calculated.

  Therefore, the detection data generation unit 64a corresponding to the electronic primary document inclination calculation unit 65a uses a known conversion method from R (red), G (green), and B (blue) image data acquired from the buffer memory 43. First, Lab data (luminance data) is generated. The Lab data (luminance data) includes L (brightness: lightness), a (color area based on the standard: red if a is +, and green complementary color if a is-), b (color area based on the standard). : b is yellow when it is +, and complementary blue when it is-. The luminance data is not limited to Lab data, but may be gray information, and is L data that has undergone color conversion.

  The detection data generation unit 64a filters the luminance data with, for example, an edge extraction filter such as a Sobel filter, thereby extracting the edge portion that is the document edge, and using the edge extraction data as the edge detection threshold value. To generate edge detection data.

  That is, as shown in FIG. 13, the detection data generation unit 64a includes luminance data in the detected position A (shown in FIG. 13A) in the read image data (scanned image) obtained by reading the document. Data changes in the sub-scanning direction at P1) and detection position B (P2). Here, the counter plate region shown in FIG. 13 is a region where the white plate 15c is read. The white plate 15c is usually white, but appears as a small data change in the read image data due to floating dust or dirt. Then, the detection data generation unit 64a checks changes in luminance data generated from the image data corresponding to the detection position A and the detection position B, and as shown in FIG. Are extracted as edge components. For example, the detection data generation unit 64a performs edge detection by performing edge extraction filter processing such as a Sobel filter, and performs binarization processing on the data to obtain an edge extraction result. . Further, the detection data generation unit 64a compares the edge extraction result after the binarization processing with a predetermined threshold (for example, “80”), and as shown in FIG. ]) The following part is defined as an edge part, and a change point where “0” is changed to “80” is determined as the document edge. The detection data generation unit 64a outputs the determination result to the electronic primary document inclination calculation unit 65a as an edge detection result signal (a signal that changes from “0” to “255”). For example, the detection data generation unit 64a determines the number of lines from the head of the image to the edge change point at each of the detection position A and the detection position B, the document end y1 at the detection position A, y1 = 100th line, The document end y2 at the detection position B is counted as y2 = 116th line, and the count result is output to the electronic primary document inclination calculation unit 65a as the document end position.

  Then, the electronic primary document inclination calculation unit 65a is based on the detection position A from the detection data generation unit 64a and the document end positions y1 and y2 at the detection position B and (the number of pixels ABs between the detection positions A and B). The first document inclination d1 is calculated by the following equation (1).

  Assuming that y1 = 100, y2 = 116, and ABs = 2362 (100 mm), the first document inclination d1 is about 0.39 degrees according to the following equation (4). In this embodiment, the reading resolution is 600 dpi in both the main scanning direction and the sub-scanning direction.

First document inclination d1 = (y1-y2) / ABs
= (100-116) / 2362 = about 0.39 degrees (4)
The electronic primary document inclination calculation unit 65a outputs the calculated first document inclination d1 to the secondary document inclination calculation unit 66.

  Next, the detection data generation unit 64b corresponding to the electronic primary document inclination correction unit 65b first performs Lab data (luminance data) based on a known conversion method from the RGB image data acquired from the buffer memory 43. Is generated. As described above, the luminance data is Lab data generated by a known conversion method for RGB image data or L data that has been color-converted into gray information.

  The detection data generation unit 64b obtains a luminance difference from the generated luminance data, and detects end positions of the read image data, in particular, end positions at the detection positions P1 and P2 at the two upper ends.

  Specifically, the detection data generation unit 64b detects the document edge position in the image data as shown in FIG. 14 based on the luminance data. That is, luminance data generated from image data obtained by reading a document changes in the sub-scanning direction at the detection position A (P1) and the detection position B (P2) as shown in FIG. The detection data generation unit 64b detects the luminance data of the white plate 15c, which is a counter plate before the document portion is read, and the change point of the luminance data of the document background portion as the document edge. The color composite apparatus 1 averages, for example, data obtained by scanning the brightness of the white plate 15c, which is a reference for calculating the brightness difference in the detection data generation unit 64b, in a state in which no dust or dirt adheres at the time of factory shipment. It is generated from the value (average value) and stored in advance as a reference luminance. In FIG. 14A, the brightness of the white plate 15c, which is the opposing plate, is “253”. The detection data generation unit 64b calculates the luminance of the document area by averaging pixel data after a change point described later.

  Here, the luminance of the document area is “210” at the detection position A and “205” at the detection position B in the case of FIG. Then, the detection data generation unit 64b obtains the change point by binarizing the luminance information of the image data with the change point detection threshold (“230” in this embodiment).

  That is, as shown in FIG. 14B, the detection data generation unit 64b detects a change point that changes from “0” to “255” after binarization as a document edge, and displays the change point detection result. To do. In the case of FIG. 14B, the detection data generation unit 64b detects the detection position A as the change point at y1 = 105th line and the detection position B as the change point y2 = 120, and checks the change. The output result is output to the electronic primary document inclination calculation unit 65b.

  The electronic primary document inclination calculation unit 65b determines the second document inclination d2 from the detection position A detected by the detection data generation unit 64b and the document end positions y1 and y2 at the detection position B (between the detection positions A and B). The number of pixels (ABs) is calculated by the following equation (5). Assuming that y1 = 105, y2 = 120, and ABs = 2362, the second document inclination d2 is about 0.36 degrees from the following equation (5).

Second document inclination d2 = (y1-y2) / ABs
= (105-120) / 2362 = about 0.36 degrees (5)
The electronic primary document inclination calculation unit 65 b outputs the calculated second document inclination d 2 to the secondary document inclination calculation unit 66.

  The detection data generation unit 64c generates Lab data obtained by converting the RGB image data acquired from the buffer memory 43 into Lab space, and generates color difference data using the Lab data. Based on the generated color difference data, the detection data generation unit 64c detects the end positions of the image data, particularly the positions of the two upper ends (detection position A (P1) and detection position B (P2)), and the document. The end position is detected.

  That is, as described above, the detection data generation unit 64c generates color difference data by converting RGB of the image data into Lab, and the color difference data includes the color difference data at the detection position A (P1) and the detection position. The conversion point of B (P2) color difference data is shown as in FIG.

  Based on the generated color difference data, the detection data generation unit 64c detects the document edge position in the read image data as shown in FIG. That is, among the image data obtained by reading the original, the color difference data generated by the detection data generation unit 64c is changed in the sub-scanning direction at the detection position A and the detection position B as shown in FIG. To do. The detection data generation unit 64c detects the color difference data of the white plate 15c, which is the opposite plate before the document portion is read, and the change point of the color difference data of the document background portion as the document edge. The color composite apparatus 1 scans the color information of the white plate 15c, which is a reference for calculating the color difference in the detection data generation unit 64c, in a state where dust and dirt are not attached at the time of factory shipment, for example, an average value (Average value) is generated and stored in advance as reference color information. In FIG. 15A, the color information (data obtained by converting RGB into Lab) of the counter plate (white plate 15c) is L = 92, a = 2, and b = -12. The detection data generation unit 64c calculates the color information of the document area by averaging the pixel data after the change point.

  Now, when the color information at the detection position A (P1) is L = 88, a = −1, and b = 3, the detection data generation unit 64c determines the color difference ΔEa of the document area at the detection position A as the color difference. Applying to the following formula (6) which is a calculation formula of ΔE, “15” is calculated.

また、検出用データ生成部６４ｃは、検出位置Ｂの色情報を、Ｌ＝８７、ａ＝−２、ｂ＝３としたとき、検出位置Ｂの原稿領域部の色差ΔＥｂを、式（６）を適用して、「１６」と算出する。

Further, the detection data generation unit 64c calculates the color difference ΔEb of the document area portion at the detection position B using the equation (6) when the color information at the detection position B is L = 87, a = −2, and b = 3. Is applied to calculate “16”.

そして、検出用データ生成部６４ｃは、画像データの色情報を、変化点検出閾値（本実施例では、「１０」としている。）で、２値化処理することで、変化点を求める。

Then, the detection data generation unit 64c obtains a change point by binarizing the color information of the image data with a change point detection threshold (in this embodiment, “10”).

  That is, as shown in FIG. 15B, the detection data generating unit 64c uses the binarized “0” to “255” as the change point at the detection position A and the detection position B. Detected as the part positions y1 and y2, and outputs them to the electronic primary document inclination calculator 65c.

  The electronic primary document inclination calculation unit 65c calculates the third document inclination d3 by using the detection position A detected by the detection data generation unit 64c and the document end positions y1 and y2 at the detection position B (between the detection positions A and B). (The number of pixels ABs) is calculated by the following equation (7). If y1 = 111, y2 = 125, and ABs = 2362 (100 mm), the third document inclination d3 is about 0.34 degrees according to the following equation (7).

Third document inclination d3 = (y1-y2) / ABs (7)
d3 = (111-125) / 2362 = about 0.34 degrees The electronic primary document inclination calculation unit 65c outputs the calculated third document inclination d3 to the secondary document inclination calculation unit 66.

  Therefore, the electronic primary document inclination calculation units 65a, 65b, and 65c function as electronic inclination extraction means.

  The secondary document inclination calculation unit 66 calculates the optical primary document inclination from the detection results of the photosensor 15b among the document inclinations d1, d2, and d3 calculated by the three electronic primary document inclination calculation units 64a, 64b, and 64c. Document inclinations d1, d2, and d3 that are not far from the document inclination d0 calculated by the calculation unit 63 are extracted. The secondary document inclination calculation unit 66 calculates a final document inclination based on the extracted document inclinations d1, d2, and d3, and outputs the calculated final document inclination to the inclination correction processing unit 67. Therefore, the secondary document inclination calculation unit 66 functions as final inclination extraction means.

  The inclination correction processing unit 67 corrects the inclination of the original G, that is, the image data, based on the final original inclination calculated by the secondary original inclination calculating unit 66. The inclination correction processing unit 67 executes the inclination correction of the image data by performing a known affine transformation process on the image data, for example.

  In the above description, the color multifunction apparatus 1 uses the image data from the CCD 24 that reads the front image of the original G to calculate the electronic original inclination. May use image data from the CIS 15a that reads the back image. In addition, the color multifunction apparatus 1 may calculate the document inclination using both or either of the CCD 24 and the CIS 15a.

  The image data from the CIS 15a is image data that has already undergone processing equivalent to the processing performed by the read signal processing unit 34 on the image data from the CCD 24. Therefore, the color multifunction apparatus 1 inputs the image data from the CIS 15a to the buffer memory 43 without performing analog video processing or shading correction processing.

  The color composite apparatus 1 includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a CD-RW (Compact Disc Rewritable), and a DVD. The document inclination of the present invention recorded on a computer-readable recording medium such as (Digital Versatile Disk), USB (Universal Serial Bus) memory, SD (Secure Digital) card, MO (Magneto-Optical Disc) or the like is accurately determined. An image reading unit (image reading device) 10 for executing an image processing method for accurately determining a document inclination, which will be described later, is provided by reading an image processing program for executing an image processing method for determination and introducing it into the memory 32 or the like. It is constructed as an image processing device. This information identification program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark) or an object-oriented programming language, and is stored in the recording medium. Can be distributed.

  Next, the operation of this embodiment will be described. The color composite apparatus 1 of this embodiment accurately determines the document inclination.

  In the color composite apparatus 1, it is assumed that the document G is scanned (read) with a certain inclination with respect to the scanning direction, as shown in FIG. The color multifunction apparatus 1 appropriately processes the image data of the document G read by the image reading unit 10 with a predetermined inclination with respect to the scanning direction, and performs buffer processing under the control of the buffer memory controller 44. The data is stored in the memory 43 for each page.

  Since the read image data has a tilt, the color composite apparatus 1 stores larger data in the buffer memory 43 than the document area Gr, which is the image area of the image data, as shown in FIG. The image data indicated by the document area Gr is stored in the image area Ar.

  The color composite apparatus 1 detects the inclination of the image data (original area Gr) accumulated in the accumulated image area Ar, and as shown in FIG. 16C, the image data (original area Gr) is detected based on the detected inclination. ) Is corrected for the accumulated image area Ar.

  As shown in FIG. 16D, the color multifunction apparatus 1 cuts out the image data of the document area Gr in the accumulated image area Ar and performs output such as print output and transfer output.

  Then, in order to detect the inclination of the image data more accurately, the color composite apparatus 1 also uses a result of detecting the leading edge of the document by the photosensor 15c as shown in FIG. The document inclination is detected from the image processing.

  In other words, when the original G is set on the original tray 16 of the SDF unit 15 and the start of reading is instructed, the color composite apparatus 1 transports the original G by the SDF unit 15 and scans the original G. (Step S101).

  When the color multifunction apparatus 1 starts scanning the document, the detection time difference calculation unit 61 sets the detection time difference Δt as described above based on the detection signals S1 and S2 at the leading edge of the document G detected by the pair of photosensors 15b. A detection time difference calculation process is performed (step S102).

  On the other hand, the color composite apparatus 1 stores the image data of the original G read by the CCD 24 in the buffer memory 43 after performing the necessary image processing by the read signal processing unit 34 (step S103).

  In the color composite apparatus 1, the sub-scanning distance generation unit 62 calculates the distance Δy from the time difference Δt to the leading edge position of the document G detected by the other photosensor 15b from the leading edge position of the document G detected by the one photosensor 15b. A sub-scanning distance generation process to be calculated is performed (step S104).

  In the color composite apparatus 1, the detection data generation units 64a, 64b, and 64c read the image data stored in the buffer memory 43, respectively. Each of the detection data generation units 64a, 64b, and 64c calculates the document edge positions y1 and y2 based on the edge detection data, luminance data, and color difference data, respectively (steps S105a, S105b, and S105c).

  In the color composite apparatus 1, the optical primary document inclination calculation unit 63 calculates the optical inclination d0 of the original G as described above based on the distance Δy obtained in the sub-scanning distance generation process. Next document skew calculation processing is performed (step S106).

  Further, the color composite apparatus 1 includes an electronic primary document inclination calculation unit 65a, 65b, 65c between the document edge positions y1, y2 and the detection positions calculated by the corresponding detection data generation units 64a, 64b, 64c. Based on the number of pixels ABs, electronic first document inclinations d1, d2, and d3 are respectively calculated (steps S107a, 107b, and 107c).

  Next, in the color composite apparatus 1, the detection result of the photosensor 15b is detected by the secondary document inclination calculation unit 66 among the document inclinations d1, d2, and d3 calculated by the electronic primary document inclination calculation units 64a, 64b, and 64c. Are extracted from the document inclinations d1, d2, and d3 that are not significantly different from the document inclination d0 calculated by the optical primary document inclination calculation unit 63. The secondary document inclination calculation unit 66 performs a secondary document inclination calculation process for calculating a final document inclination based on the extracted document inclinations d1, d2, and d3 (step S108).

  In the color multifunction apparatus 1, the inclination correction processing unit 67 performs an inclination correction process for correcting the inclination of the original G, that is, the image data, based on the final original inclination, and the original inclination detection process ends (step S109). .

  Then, the color composite apparatus 1 executes the secondary document inclination calculation processing by the secondary document inclination calculation unit 66 as shown in FIG. The secondary document skew calculation unit 66 first initializes Sum and Cnt, which are calculation flags (Sum = 0, Cnt = 0) (step S201). Here, Sum is a variable indicating the sum of the slopes for calculating the sum of the slopes, and Cnt is a counter.

  Next, the secondary document inclination calculation unit 66 uses the value obtained by adding or subtracting the preset determination threshold value α to the optical inclination d0 as the determination condition (d0−α <d1 <d0 + α). It is checked whether the determination condition is satisfied (step S202). This determination threshold value α is a threshold value for determining whether or not the document inclination to be processed is used for calculating the average value. For example, α = 0.02 / 100 is set. Therefore, the secondary document inclination calculation unit 66 determines whether the document inclination d1 satisfies the determination condition d0−0.02 / 100 <d1 <d0 + 0.02 / 100.

  If the document inclination d1 satisfies the determination condition in step S202 (YES in step S202), the secondary document inclination calculation unit 66 adds the document inclination d1 to the total inclination Sum, and the number of additions Is incremented (+1) by “1” (step S203).

  Next, the secondary document skew calculation unit 66 checks whether the document skew d2 satisfies the determination condition (d0−α <d2 <d0 + α) (step S204).

  In step S202, if the document inclination d1 does not satisfy the determination condition (NO in step S202), the secondary document inclination calculation unit 66 does not add the total inclination Sum and the counter Cnt, and does not add the document. It is checked whether the inclination d2 satisfies the determination condition (step S204).

  If the document inclination d2 satisfies the determination condition in step S204 (YES in step S204), the secondary document inclination calculation unit 66 adds the document inclination d2 to the total inclination Sum, and sets the counter Cnt to “ 1 "is incremented (step S205).

  Next, the secondary document skew calculation unit 66 checks whether the document skew d3 satisfies the determination condition (d0−α <d3 <d0 + α) (step S206).

  In step S204, if the document inclination d2 does not satisfy the determination condition (NO in step S204), the secondary document inclination calculation unit 66 does not add the inclination total Sum and the counter Cnt, and the document inclination d3. Checks whether the determination condition is satisfied (step S206).

  If the document inclination d3 satisfies the determination condition in step S206 (YES in step S206), the secondary document inclination calculation unit 66 adds the document inclination d3 to the total inclination Sum, and sets the counter Cnt to “ 1 "is incremented (step S207).

  Next, the secondary document skew calculation unit 66 determines whether the value of the counter Cnt is “1” or more, that is, whether one or more document skews calculated electronically satisfy the determination condition. A check is made (step S208).

  If the document inclination d3 satisfies the determination condition in step S206 (YES in step S206), the secondary document inclination calculation unit 66 does not add the total inclination Sum and the counter Cnt, and the counter Cnt It is checked whether the value is equal to or greater than “1” (step S208).

  If the value of the counter Cnt is “1” or more in step S208 (YES in step S208), the secondary document inclination calculation unit 66 calculates the document inclination a by the following equation (8), The secondary document skew calculation process ends.

a = Sum / Cnt (8)
If the value of the counter Cnt is “0” in step S208 (NO in step S208), the secondary document inclination calculation unit 66 determines whether the photosensor inclination adoption presence / absence variable Cor is “ON”. Is checked (step S210).

  Whether the photo sensor tilt adoption variable Cor corresponds to the optical document tilt d0 using the photo sensor 15b as the document tilt when all the electronic document tilts d1, d2, and d3 do not satisfy the determination condition. This is a variable indicating whether or not, and can be appropriately set by the user in advance.

  In step S210, if the photosensor tilt adoption presence / absence variable Cor is “ON” (YES in step S210), the secondary document tilt calculation unit 66 notifies that the document tilt accuracy is poor (step S211). ). The secondary document tilt calculation unit 66 notifies that the document tilt accuracy is poor, for example, by displaying a message to that effect on the display of the operation display unit. Note that the secondary document skew calculation unit 66 may select whether or not to adopt the optical document skew d0 as the document skew a when the notification that the document skew accuracy is poor is output. In this case, the secondary document inclination calculation unit 66 displays a selection screen as to whether or not to adopt the optical original inclination d0 as the original inclination a on the display, and the user sets the optical original inclination d0 as the original inclination a. Whether to adopt or not can be selected.

  The secondary document skew calculation unit 66 adopts the optical document skew d0 as the document skew a, and ends the secondary document skew calculation process (step S212).

  If the photosensor tilt adoption variable Cor is “OFF” in step S210 (NO in step S210), the secondary document tilt calculation unit 66 notifies that the document tilt cannot be detected. (Step S213). The secondary document skew calculation unit 66 notifies the fact that the document skew cannot be detected, for example, by displaying a message such as “Document skew correction not performed” on the display of the operation display unit. Do. Note that the secondary document tilt calculation unit 66 may select whether or not to adopt the optical document tilt d0 as the document tilt a at the time when the notification that the document tilt detection could not be performed is output.

  The secondary document skew calculation unit 66 sets the document skew a to “0” and ends the secondary document skew calculation process (step S214).

  In the secondary document inclination calculation process of FIG. 18, the secondary document inclination calculation unit 66 specifically processes as follows.

  Now, it is assumed that the document inclination d0 by the photosensor 15b is d0 = −0.615 mm / 100 mm (about −0.352 degrees) as described above. Further, as described above, the electronic document inclinations d1, d2, and d3 are determined as follows: d1 = −16 / 2362 (approximately −0.39 degrees) = − 0.6773 mm / 100 mm, d2 = −15 / 2362 (approximately − 0.36 degrees) = − 0.6351 mm / 100 mm, d3 = −14 / 2362 (about −0.34 degrees) = − 0.593 mm / 100 mm. The determination threshold value α for determining whether or not the electronic document inclinations d1, d2, and d3 are used for calculating the average value is set to α = 0.02 / 100.

  Then, in step S201, the secondary document inclination calculation unit 66 initializes the total inclination Sum and the counter Cnt, and sequentially checks whether the original inclination d1 to the original inclination d3 satisfy the determination condition (steps S202 to S207). ). When the determination condition is satisfied, the secondary document inclination calculation unit 66 adds the document inclinations d1, d2, and d3 to the total inclination Sum, and adds “1” to the counter Cnt, but does not satisfy the determination condition. In some cases, the sum of the slopes Sum and the counter Cnt are not added.

  Now, with respect to the document inclination d1, (−0.615 / 100−0.02 / 100) <− 0.6773 / 100 <(− 0.615 / 100 + 0.02 / 100) holds under the above conditions. Absent. Therefore, the secondary document inclination calculation unit 66 does not add the total inclination Sum and the counter Cnt. However, when the document inclination d1 is not the above value but satisfies the determination condition, Sum = Sum + d1 and Cnt = Cnt + 1 are executed.

  The document inclination d2 and the document inclination d3 satisfy the determination conditions. Accordingly, the secondary document inclination calculation unit 66 calculates Sum = d2 + d3 = (− 0.6351 mm / 100 mm) + (− 0.593 mm / 100 mm) = − 0.61411 / 100 (= about −0.352 degrees), Cnt = 2 is calculated.

  Then, when there are no document inclinations d1, d2, and d3 satisfying the determination condition, the secondary document inclination calculation unit 66 performs information notification on the display of the operation display unit, and determines the document inclination a as an optical type. The document inclination d0 or “0” is set (steps S210 to S214).

  This information notification method is not limited to displaying information on the display, but may be a warning light, warning sound, e-mail transmission, or the like.

  As described above, the color composite apparatus 1 according to the present exemplary embodiment uses the scanning optical system (image reading unit) 26 that reads an image of the conveyed original G and outputs image data, and the image data output from the scanning optical system 26. Based on the detection data generation units (electronic end detection means) 64a, 64b, 64c for detecting the leading end of the transported original G in the transport direction as an electronic end, and the transport of the original G to be transported Based on the optical end detection means comprising a photo sensor 15b that optically detects the front end in the transport direction as an optical end, a detection time difference calculation unit 61, and a sub-scanning distance generation unit 62, and the electronic end, An electronic primary document inclination calculation unit (electronic inclination extraction means) 65a to 65c that extracts the inclination of the leading edge of the document G in the conveyance direction as an electronic inclination, and the optical edge of the original G Transport direction destination An optical primary document inclination calculation unit (optical inclination extraction means) 63 for extracting the inclination of the part as an optical inclination, and an original inclination a which is a final inclination of the original G from the electronic inclination and the optical inclination. And a secondary document inclination calculation unit (final inclination extraction means) 66 for extraction.

  Therefore, the final inclination of the original G can be obtained with high accuracy based on the optical inclination based on the optical end and the electronic inclination based on the electronic end, and the original inclination a can be accurately determined. .

  Further, the color composite apparatus 1 according to the present embodiment is transported based on an image reading processing step for reading an image of a transported original G and outputting image data, and image data output from the image reading processing step. An electronic end detection step for detecting the leading end in the transport direction of the document G as an electronic end, and an optical type for optically detecting the leading end in the transport direction of the transported document G as an optical end. Based on the edge detection processing step, on the basis of the electronic edge, an electronic inclination extraction processing step for extracting the inclination of the leading edge in the conveyance direction of the document G as an electronic inclination, and on the basis of the optical edge, An optical tilt extraction process step for extracting the tilt of the leading end of the document G in the transport direction as an optical tilt, and the document tilt a which is the final tilt of the document G is extracted from the electronic tilt and the optical tilt. And a final slope extraction processing step of, performing an image processing method having.

  Therefore, the final inclination of the original G can be obtained with high accuracy based on the optical inclination based on the optical end and the electronic inclination based on the electronic end, and the original inclination a can be accurately determined. .

  Further, the color composite apparatus 1 according to the present embodiment is based on an image reading process for reading an image of a conveyed document G and outputting image data to a control processor such as a CPU 31 and image data output by the image reading process. An electronic edge detection process for detecting the leading edge of the conveyed document G in the conveying direction as an electronic edge, and an optically edge of the conveyed document G in the conveying direction as an optical edge. Based on the optical edge detection process to detect, the electronic inclination extraction process to extract the inclination of the leading edge in the transport direction of the document G as the electronic inclination based on the electronic edge, and the optical edge Then, an optical tilt extraction process for extracting the tilt of the leading end of the document G in the transport direction as an optical tilt, and a document tilt a which is the final tilt of the document G is extracted from the electronic tilt and the optical tilt. Final tilt And the image processing program to be executed and output process, the.

  Therefore, the final inclination of the original G can be obtained with high accuracy based on the optical inclination based on the optical end and the electronic inclination based on the electronic end, and the original inclination a can be accurately determined. .

  In the color composite apparatus 1 of the present embodiment, the secondary document inclination calculation unit 66 determines whether the electronic inclination is within a predetermined determination threshold α with respect to the optical inclination. If it is within the determination threshold α, the original inclination a which is the final inclination is extracted based on the electronic inclination, and if it is outside the determination threshold α, it is the final inclination based on the optical inclination. Document skew a is extracted.

  Therefore, the original inclination a can be obtained from the electronic inclination obtained by omitting the electronic inclination away from the optical inclination, and the original inclination a can be determined more accurately.

  Further, in the color composite apparatus 1 of the present embodiment, the detection data generation unit (electronic end detection unit) 64a, 64b, 64c applies the image data read by the scanning optical system (image reading unit) 26 to the image data. On the other hand, predetermined image processing is performed, and the electronic end portion is detected based on the image data after the image processing.

  Accordingly, it is possible to detect the edge of the document G based on the image data that has been subjected to image processing suitable for detecting the edge of the document G, and to determine the inclination of the document G, thereby further accurately determining the document inclination a. Can be determined.

  Further, in the color composite apparatus 1 of the present embodiment, the detection data generation unit (electronic end detection unit) 64a, 64b, 64c applies the image data read by the scanning optical system (image reading unit) 26 to the image data. On the other hand, a plurality of different image processes are performed in parallel, and the electronic end portions are detected based on the respective image data after the image processing, and the electronic primary document inclination calculation unit (electronic inclination is calculated). (Extracting means) 65a to 65c each extract the electronic inclination based on the plurality of electronic end portions.

  Therefore, based on a plurality of image data subjected to different image processing suitable for detecting the edge of the document G, the edge of the document G can be detected and the inclination of the document G can be obtained. The document inclination a can be more accurately determined from the plurality of document inclinations.

  Further, in the color composite apparatus 1 of the present embodiment, the secondary document inclination calculation unit (final inclination extraction means) 66 has an average value of the electronic inclinations existing within the determination threshold among the plurality of electronic inclinations. Based on the above, the final inclination is extracted.

  Therefore, based on a plurality of image data subjected to different image processing suitable for detecting the edge of the document G, the edge of the document G can be detected and the inclination of the document G can be obtained. The document inclination a can be more accurately determined from the plurality of document inclinations.

  In the color composite apparatus 1 of the present embodiment, when the secondary document inclination calculation unit (final inclination extraction unit) 66 does not have the electronic inclination existing within the determination threshold value α, the optical inclination is calculated. Based on the above, the final inclination is extracted.

  Therefore, even when the electronic tilt does not exist within the determination threshold α, the document tilt a can be obtained based on the optical tilt.

  Further, the color composite apparatus 1 of the present embodiment further includes notifying means (operation display section or the like) for notifying and outputting information, and a secondary document inclination calculating section (final inclination extracting means) 66 is within the determination threshold α. If the electronic tilt present in the document is absent, information indicating that the accuracy of extracting the final tilt of the document G is low is output to a notification means such as the operation display unit.

  Therefore, when the accuracy of the obtained final document inclination a is low, the user can be made aware of this fact, and the usability can be improved.

  Further, the color multifunction apparatus 1 according to the present embodiment sets whether or not to extract the final inclination based on the optical inclination when the electronic inclination existing within the determination threshold α is absent. Setting means (operation display unit or the like) for performing a second document inclination calculation unit (final inclination extraction means) when the electronic inclination existing within the determination threshold α is absent. If the final inclination is set to be extracted based on the optical inclination, the final inclination is extracted based on the optical inclination, and the setting means converts the final inclination to the optical inclination. If the extraction based on the non-setting is not set, the final inclination is that there is no document inclination.

  Accordingly, when the accuracy of the obtained final document inclination a is low, the original inclination a which is the final inclination can be obtained according to the user's instruction, and the original inclination a corresponding to the use situation is used. Thus, usability can be improved.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

DESCRIPTION OF SYMBOLS 1 Color compound apparatus 10 Image reading part (image reading apparatus)
11 Housing 12 Document reading table (document table)
13 Document holding plate 14 Document transport section 15 SDF unit 15a CIS
15b Photosensor 15c White plate 15d SDF window 15e Transmission glass 16 Document tray 17 Document conveyance stepping motor 18 Separation roller 19 Conveyance roller 20 White reference plate 21 First traveling body 21a Light source 21b Mirror 22 Second traveling body 22a, 22b Mirror 23 Lens 24 CCD
25 traveling body stepping motor 26 scanning optical system (image reading means)
G Document P1 (A) First detection position P2 (B) Second detection position 31 CPU
32 Memory 33 Memory Controller 34 Read Signal Processing Unit 35 Image Processing Unit 36 Write Signal Processing Unit 37 LD
38 LD drive unit 39 CCD drive unit 40 Light source driver 41 Document transport motor driver 42 Running body motor driver 43 Buffer memory 44 Buffer memory controller 50 Image processing device 51 Analog video processing unit 51a Preamplifier circuit 51b Variable amplification circuit 51c A / D converter 52 Shading correction processing unit 52a Black arithmetic circuit 52b Shading correction arithmetic circuit 52c Line buffer 61 Detection time difference calculation unit 62 Sub-scanning distance generation unit 63 Optical primary document inclination calculation unit 64a, 64b, 64c Detection data generation units 65a, 65b, 65c Electronic primary document inclination calculation section 66 Secondary document inclination calculation section 67 Inclination correction processing section S1, S2 Detection signal CLK clock

JP 2012-244507 A

Claims (10)

Image reading means for reading an image of a conveyed document and outputting image data;
An electronic end detection unit that detects, as an electronic end, a leading end in the transport direction of the document to be transported based on image data output from the image reading unit;
An optical edge detection means for optically detecting the leading edge of the conveyed document in the conveyance direction as an optical edge;
An electronic inclination extracting means for extracting, as an electronic inclination, an inclination of the leading end of the document in the conveyance direction based on the electronic end;
An optical inclination extracting means for extracting the inclination of the leading end of the document in the conveying direction as an optical inclination based on the optical end;
Final inclination extraction means for extracting the final inclination of the document from the electronic inclination and the optical inclination;
Equipped with a,
The final inclination extracting means includes
It is determined whether the electronic tilt is within a predetermined determination threshold with respect to the optical tilt, and if it is within the determination threshold, the final tilt is extracted based on the electronic tilt, An image processing apparatus that extracts the final inclination based on the optical inclination when it is outside the determination threshold . The electronic end detection means is
On the image data read by the image reading means, it performs predetermined image processing, based on the image data after the image processing, according to claim 1 Symbol, characterized by detecting said electronic end The image processing apparatus described. The electronic end detection means is
A plurality of different image processes are performed in parallel on the image data read by the image reading unit, and the electronic end portions are detected based on the image data after the image processing,
The electronic tilt extraction means includes
Based on the plurality of the electronic end, respectively and extracting the electronic tilt claim 1 Symbol mounting image processing apparatus. The final inclination extracting means includes
The image processing apparatus according to claim 3 , wherein the final inclination is extracted based on an average value of the electronic inclinations existing within the determination threshold among the plurality of electronic inclinations. The final inclination extracting means includes
When the electronic tilt that exists in the determination threshold is absent, the image as claimed in any one of claims 4, wherein the extracting the final slope on the basis of the optical slope Processing equipment. The image processing apparatus includes:
An informing means for informing and outputting information,
In addition,
The final inclination extracting means includes
Wherein when said electronic tilt present in the determination threshold is absent, wherein said final tilt information extraction accuracy is low effect of the document from claim 3, characterized in that broadcast output to the notification means Item 6. The image processing apparatus according to Item 5 . The image processing apparatus includes:
Setting means for setting whether or not to extract the final inclination based on the optical inclination when the electronic inclination existing within the determination threshold is nonexistent,
In addition,
The final inclination extracting means includes
If the setting means is configured to extract the final inclination based on the optical inclination when the electronic inclination existing within the determination threshold is not present, the final inclination is calculated based on the optical inclination. Extracting based on the inclination, and extracting the final inclination based on the optical inclination by the setting means is not set, and the final inclination is that there is no document inclination. the image processing apparatus according to any one of claims 1 to 6 to. An image reading apparatus including an image processing unit that reads an image of a document with an image reading unit and detects and corrects an inclination of read image data of the document read by the image reading unit,
Wherein the image processing unit, an image reading apparatus characterized by comprising an image processing apparatus according to any one of claims 1 to 7. An image reading processing step of reading an image of a conveyed document and outputting image data;
An electronic edge detection processing step for detecting, as an electronic edge, a leading edge in the conveyance direction of the document to be conveyed, based on image data output by the image reading processing step;
An optical end detection processing step for optically detecting the front end in the transport direction of the document to be transported as an optical end;
An electronic inclination extraction processing step for extracting, as an electronic inclination, an inclination of the leading end portion in the transport direction of the document based on the electronic end;
An optical tilt extraction processing step for extracting the tilt of the leading end of the document in the transport direction as an optical tilt based on the optical end;
A final inclination extraction processing step of extracting a final inclination of the document from the electronic inclination and the optical inclination;
I have a,
In the final inclination extraction processing step ,
It is determined whether the electronic tilt is within a predetermined determination threshold with respect to the optical tilt, and if it is within the determination threshold, the final tilt is extracted based on the electronic tilt, When it is outside the determination threshold, the final inclination is extracted based on the optical inclination.
An image processing method. To the control processor,
An image reading process for reading an image of a conveyed document and outputting image data;
An electronic edge detection process for detecting, as an electronic edge, a leading edge in the conveyance direction of the document to be conveyed, based on image data output by the image reading process;
An optical end detection process for optically detecting the front end of the transported document in the transport direction as an optical end;
An electronic inclination extraction process for extracting, as an electronic inclination, an inclination of the leading end of the document in the transport direction based on the electronic end;
An optical tilt extraction process for extracting, as the optical tilt, the tilt of the leading end of the document in the transport direction based on the optical end;
Final inclination extraction processing for extracting the final inclination of the document from the electronic inclination and the optical inclination;
In the final inclination extraction process ,
It is determined whether the electronic tilt is within a predetermined determination threshold with respect to the optical tilt, and if it is within the determination threshold, the final tilt is extracted based on the electronic tilt, A process of extracting the final tilt based on the optical tilt if it is outside the determination threshold;
An image processing program for executing

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