JP2012191315A - Image reader, image forming device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a missing part of a document such as a hole of perforator, etc. without prolonging a processing time.SOLUTION: A background area detection unit 51 identifies a background area that is a missing part in an entire document by identifying a part indicating a maximal value, i.e. 255, of the expressing range of an image data converted by a signal conversion section 41. Of the shadow area identified by a shadow area detection unit 52, an erasure area determination unit 53 identifies an image within a range of a pixel number predetermined on the basis of the pixel number of the background area, identified by the background area detection unit 51, as the image in the shadow area to be erased. A shadow area erasing processing unit 54 erases the image identified as the image of the shadow area to be erased by the erasure area determination unit 53 from the image of the shadow area surrounding the background area by converting to a predetermined white background.

Description

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

  Patent Document 1 discloses an image forming apparatus that stores a punch hole pattern in advance, identifies the punch hole by collating with the punch hole pattern, and erases and removes punch hole image data. It is disclosed.

  Patent Document 2 discloses an image reading apparatus that detects a punch hole by performing pre-scanning before actually reading a document image.

  Patent Document 3 discloses an image processing apparatus in which punch hole candidates are extracted by searching a preset search range of a document image, and punch holes are identified and removed from the extracted punch hole candidates. Has been.

Japanese Patent No. 3518639 JP 2001-69317 A JP 2004-80341 A

  An object of the present invention is to provide an image reading apparatus, an image forming apparatus, and a program capable of detecting an area where no original exists in an entire area of the original such as a punch hole without increasing the processing time. That is.

[Image processing device]
According to a first aspect of the present invention, there is provided an image reading unit that reads an image of an original as an image signal by irradiating the original with light from a light source and reading the reflected light.
Conversion means for converting an image signal of a document read by the image reading means into image data expressed in a preset range;
An adjusting means for adjusting the converting means so that an image signal obtained by reading a white area of a printing paper used as a document by the image reading means does not become a maximum value in a range that can be expressed by image data;
A member arranged on the back side of the document read by the image reading unit and configured to saturate at least one color of the image signals read by the image reading unit to a maximum value that can be expressed by image data. A reflected member,
Detecting means for detecting a background area, which is an area in which no document exists in the entire document area, by detecting an area having a maximum value that can be expressed in the image data converted by the converting means; An image reading apparatus provided.

  According to a second aspect of the present invention, an image of a shadow area around the background area detected by the detecting unit and having a density value larger than a preset value is converted into preset white background data. The image reading apparatus according to claim 1, further comprising an erasing unit that erases an image in a shadow area around the area.

  The present invention according to claim 3 further comprises determination means for determining an image within a preset number of pixels from the pixels in the background area detected by the detection means as an image in the shadow area. It is an image reading apparatus of description.

  According to a fourth aspect of the present invention, the image processing apparatus further includes a determination unit that determines, as a shadow region image, images that are continuously adjacent to each other within a preset number of pixels from the background region pixels detected by the detection unit. The image reading apparatus according to claim 2.

[Image forming apparatus]
According to a fifth aspect of the present invention, there is provided image reading means for reading an image of a document as an image signal by irradiating the document with light from a light source and reading the reflected light.
Conversion means for converting an image signal of a document read by the image reading means into image data expressed in a preset range;
An adjusting means for adjusting the converting means so that an image signal obtained by reading a white area of a printing paper used as a document by the image reading means does not become a maximum value in a range that can be expressed by image data;
A member arranged on the back side of the document read by the image reading unit and configured to saturate at least one color of the image signals read by the image reading unit to a maximum value that can be expressed by image data. A reflected member,
Detecting means for detecting a background area that is an area in which no document exists in the entire document area by detecting an area that is the maximum value of the range that can be expressed in the image data converted by the converting means;
The shadow area image around the background area detected by the detection means is erased by converting the shadow area image whose density value is larger than a preset value into preset white background data. Erasing means to perform,
The image forming apparatus includes an image output unit that outputs a document image after the image in the shadow area around the background area is erased by the erasing unit.

[program]
The present invention according to claim 6 is a step of reading an image of an original as an image signal by irradiating the original with light from a light source and reading the reflected light;
Converting the image signal of the read document into image data expressed in a preset range;
And detecting a background area that is an area in which no document exists in the entire document area by detecting an area that is the maximum value that can be expressed in the converted image data. It is a program.

  According to the first aspect of the present invention, an area where the original does not exist, such as a punch hole, is detected without increasing the processing time compared to a case where the original configuration does not exist. It is possible to provide an image processing apparatus that can

  According to the second aspect of the present invention, in addition to the effect obtained by the first aspect of the present invention, an image processing apparatus capable of erasing an image of a shadow region existing in a background region such as a punch hole is provided. can do.

  According to the third aspect of the present invention, in addition to the effect obtained by the second aspect of the present invention, an image of a shadow region existing within a preset number of pixels of a background region such as a punch hole is obtained. An image processing apparatus that can be erased can be provided.

  According to the present invention of claim 4, in addition to the effect obtained by the present invention of claim 2, images that are continuously adjacent to each other within a preset number of pixels from a background region such as a punch hole are obtained. An image processing apparatus that can be erased can be provided.

  According to the fifth aspect of the present invention, an area where the original does not exist, such as a punch hole, is detected without increasing the processing time compared to the case where the present configuration is not provided. It is possible to provide an image forming apparatus capable of performing the above.

  According to the sixth aspect of the present invention, an area where the original is not present in the entire area of the original such as a punch hole is detected without increasing the processing time compared to the case where the present configuration is not provided. A program can be provided.

1 is a diagram illustrating a configuration of an image forming system according to an embodiment of the present invention. 1 is a block diagram illustrating a hardware configuration of an image forming apparatus 10 according to an embodiment of the present invention. 1 is a diagram illustrating a functional configuration around an image reading apparatus in an image forming apparatus 10 according to an embodiment of the present invention. 6 is a diagram illustrating an example of a relationship between a signal level of an image signal from an image reading unit and a conversion value of image data in a conversion process in a signal conversion unit 41. FIG. It is a block diagram which shows the structure of the image process part 42 shown in FIG. It is a figure which shows the specific example of the determination process of the image of the shadow area | region of the erasure | elimination object in the erasure | termination area determination part 53. FIG. 6 is a flowchart illustrating a flow of a shadow area erasing process in the image reading apparatus according to the embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a document in which a sheet end 71 and two punch holes 72 are present. FIGS. 9A and 9B are an enlarged view around the paper edge 71 in the document shown in FIG. 8 (FIG. 9A) and an enlarged view around the punch hole 72 (FIG. 9B). FIG. 9 is a diagram illustrating an example of a relationship between a pixel value of image data from the signal conversion unit 41 and a data frequency when the document image illustrated in FIG. 8 is read. FIG. 9 is a diagram showing an image in which a shadow area caused by a sheet edge 71 and a shadow area caused by a punch hole 72 are erased from the image shown in FIG.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an image forming system according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming system according to an embodiment of the present invention includes an image forming apparatus 10 and a terminal device 20 connected to each other via a network 30. The terminal device 20 generates print data and transmits the print data generated via the network 30 to the image forming apparatus 10. The image forming apparatus 10 receives the print data transmitted from the terminal device 20 and outputs an image corresponding to the print data on a sheet. The image forming apparatus 10 is an apparatus called a so-called multi-function machine having a plurality of functions such as a print function, a scan function, a copy function, and a facsimile function.

  Next, FIG. 2 shows a hardware configuration of the image forming apparatus 10 in the image forming system of the present embodiment.

  As shown in FIG. 2, the image forming apparatus 10 transmits and receives data to and from an external device or the like via a CPU 11, a memory 12, a storage device 13 such as a hard disk drive (HDD), and a network 30. A communication interface (IF) 14, a touch panel or liquid crystal display, and a user interface (UI) device 15 including a keyboard, a scanner 16, and a print engine 17 are included. These components are connected to each other via a control bus 18.

  The CPU 11 executes predetermined processing based on a control program stored in the memory 12 or the storage device 13 and controls the operation of the image forming apparatus 10.

  In the present embodiment, the CPU 11 has been described as reading and executing a control program stored in the memory 12 or the storage device 13, but the program is stored in a storage medium such as a CD-ROM and stored in the CPU 11. It is also possible to provide.

  FIG. 3 shows a functional configuration around the image reading apparatus in the image forming apparatus 10 realized by executing the control program.

  As shown in FIG. 3, the image reading apparatus in the image forming apparatus 10 of the present embodiment includes a lid part 40 and a main body part 50. The lid 40 is provided with an automatic double-sided document feeder called a so-called DADF (Duplex Auto Document Feeder), which enables automatic document feeding.

  The lid 40 includes a document tray 26, a document separation roll 21 provided at a standby position of the document 60 placed on the document tray 26, a document transport roll 22 that transports the document, and a discharge roll 24. And a reflection member 23. A plurality of pages of documents are sequentially conveyed to a predetermined document reading position by these document separation roll 21, document transport roll 22, discharge roll 24, and the like.

  The main body 50 includes a platen glass 25, an image reading unit 70 for reading an image of a document conveyed to a document reading position by a document conveying unit such as a document conveying roll 22, a signal conversion unit 41, an image A processing unit 42 and a dynamic range adjustment unit 43 are included.

  The image reading unit 70 includes a xenon lamp 31 that is a light source for irradiating a document, reflection mirrors 32 and 33, an imaging lens 34, and a photoelectric conversion element 35 such as a CCD. The image reading section 70 irradiates the original with light from the xenon lamp 31 and reads the reflected light to read the original image as an image signal.

  The image reading unit 70 is provided on a carriage (not shown) and is movable in the sub-scanning direction. Therefore, when reading an image of a document placed on the platen glass 25, the image reading unit 70 can read the document while moving in the sub-scanning direction. Further, when reading an image of a document placed on the document tray 26, the image reading unit 70, as shown in FIG. 3, is a document reading position where the document is sequentially conveyed by the document conveyance roll 22 or the like. The image of the document conveyed from the document tray 26 can be sequentially read by moving to the position.

  The signal conversion unit 41 converts the image signal of the document read by the image reading unit 70 into image data expressed in a preset range. Specifically, the signal conversion unit 41 converts the analog signal from the image reading unit 70 into image data in the range of 0 to 255 represented by 8 bits. Here, when the image data is 0, the luminance is the darkest, and when the image data is 255, the luminance is the brightest.

  The dynamic range adjustment unit 43 performs signal conversion so that the image signal obtained by reading the white background area of the printing paper used as a document by the image reading unit 70 does not become the maximum value in the range (0 to 255) that can be expressed by the image data. The dynamic range of the unit 41 is adjusted.

  In the lid portion 40, a reflection member 23 is provided so as to cover the back surface of the conveyed document in the main scanning direction. The reflecting member 23 is disposed on the back side of the document read by the image reading unit 70, and at least one of the image signals read by the image reading unit 70 is saturated to the maximum value that can be represented by the image data. It is comprised by the member which does.

  The brightness index L * in the case where data obtained by imaging the white portion of a general white printing paper is expressed in the L * a * b * color system is in the range of L * <97. For this reason, by using a highly reflective member such as L *> 97 as the reflecting member 23, the image signal obtained by reading the reflecting member 23 is not saturated with the image signal obtained by reading the white background portion of the printing paper. Setting that saturates is possible.

  The reflection member 23 is installed at an angle such that the illumination light from the xenon lamp 31 is regularly reflected on a path that reaches the photoelectric conversion element 35 via the reflection mirror 33 and the imaging lens 34.

  Here, FIG. 4 shows an example of the relationship between the signal level of the image signal from the image reading unit 70 and the conversion value of the image data in the conversion process in the signal conversion unit 41.

  In the graph shown in FIG. 4, the signal level of the image signal obtained by reading the white background portion of the printing paper by the image reading unit 70 is less than α. Therefore, the conversion value when the signal level obtained by reading the white background portion of the printing paper is converted into image data is less than 255. However, the signal level of the image signal read from the reflecting member 23 is higher than α. Therefore, when the reflected light from the reflecting member 32 is input to the photoelectric conversion element 35, the signal conversion unit 41 outputs 255 which is the maximum value as image data.

  The image processing unit 42 has a function of performing various types of image processing on the image data converted into a digital signal by the signal conversion unit 41. Specifically, as shown in FIG. 5, the image processing unit 42 includes a background region detection unit 51, a shadow region detection unit 52, an erasure region determination unit 53, and a shadow region erasure processing unit 54. Yes.

  The background region detection unit 51 detects the maximum value of the range that can be expressed in the image data converted by the signal conversion unit 41, that is, a region that is 255, so that the document does not exist in the entire document region. A background region that is a (missing region) is detected.

  Specifically, the background region detection unit 51 compares the value of each pixel of the image data from the signal conversion unit 41 with a preset background determination threshold value (for example, 254), respectively, to thereby determine the pixel of the image data. Is greater than the background determination threshold, the pixel is determined to be a pixel included in the background area. In this case, for example, the background area detection unit 51 outputs “1” for the pixels included in the background area and “0” for the pixels not included in the background area as the background determination signal. To do.

  The shadow area detection unit 52 detects a shadow area whose density value is larger than a preset value in the image data from the signal conversion unit 41. Specifically, the shadow area detection unit 52 compares the value of each pixel of the image data from the signal conversion unit 41 with a preset shadow determination threshold value (for example, 128), and compares the pixel value of the image data with each other. Is less than the shadow determination threshold, it is determined that the pixel is a pixel included in the shadow area. In this case, for example, the shadow area detection unit 52 outputs “1” for the pixels included in the shadow area and “0” for the pixels not included in the shadow area as the shadow area determination signal. Output.

  The erasure area determination unit 53 includes pixels of the background area detected by the background area detection unit 51 (background determination signal = 1) among the shadow areas detected by the shadow area detection unit 52 (areas with shadow determination signal = 1). Are determined as images in the shadow area to be erased, within the range of the preset number of pixels (erase range pixel number M).

  For example, when the erasure range pixel number M is 3 pixels, the erasure area determination unit 53, as shown in FIG. 6A, the pixels in the shadow area within the range of 3 pixels from the image determined as the background area 91 to 93, 96, 97, and 98 are determined as pixels to be erased.

  It should be noted that the erasure area determination unit 53 deletes images that are adjacent to each other within the preset number of pixels (the number of consecutive erasure limit pixels N) from the pixels in the background area detected by the shadow area detection unit 52. The image may be determined as an image of the shadow area.

  In this case, for example, when the continuous erasure limit pixel number N is set to 3 pixels, the erasure area determination unit 53 continues within 3 pixels from the image determined as the background area as shown in FIG. Then, adjacent pixels 91 to 93, 96, and 97 in the shadow area are determined as pixels to be erased. Here, the pixels 98 in the shadow area are not included in the erasure target because they are not adjacent to the background area.

  Further, the erasure area determination unit 53 may perform determination considering the number of adjacent gap pixels in determining whether or not the background area is adjacent. Specifically, the erasure area determination unit 53 may determine that pixels that are within a preset number of adjacent gap pixels from the background area are adjacent to the background area. Further, the erasure area determination unit 53 may determine the area to be erased by expanding the shadow area, or remove the noise image by performing the expansion process and the contraction process of the shadow area. Also good.

  Here, the expansion process refers to, for example, a process that increases the periphery of the shadow area image by one pixel, and the contraction process refers to a process that decreases the periphery of the shadow area image by one pixel. Then, by performing the contraction process after performing the expansion process on the shadow area, it is possible to fill a small depression or hole in the shadow area, and conversely, after performing the contraction process on the shadow area, the expansion process is performed. And small protrusions and point-like noise can be removed.

  The shadow area erasure processing unit 54 erases the image of the shadow area around the background area by converting the image determined as the image of the shadow area to be erased by the erasure area determination unit 53 into preset white background data. . That is, the shadow area deletion processing unit 54 converts an image of a shadow area around the background area detected by the background area detecting unit 51 and having a density value larger than a preset value into preset white background data. As a result, the image in the shadow area around the background area is erased.

  The shadow area erasure processing unit 54 does not convert the shadow area image into preset white background data, but converts it into original background color data acquired by means for detecting the background color of the paper. Also good.

  Further, the image forming apparatus 10 according to the present embodiment includes an image output unit 80. The image output unit 80 outputs the original image after the shadow region image around the background region has been deleted by the shadow region deletion processing unit 54 on the printing paper.

  Next, the operation of the image reading apparatus of this embodiment will be described in detail with reference to the drawings.

  The flow of the shadow area erasing process in the image reading apparatus of the present embodiment is shown in the flowchart of FIG. In the following description, description will be made using a case where a shadow area is erased by reading a document as shown in FIG. The document shown in FIG. 8 will be described on the assumption that a sheet edge 71 in which the corner of the document is obliquely missing and two punch holes 72 exist.

  First, the background area detection unit 51 detects a saturated data area having a pixel value of 255 from the image data read by the image reading unit 70 and converted by the signal conversion unit 41, that is, the document is missing. The area is detected (step S101).

  Here, FIG. 9A shows an enlarged view around the paper edge 71 in the document shown in FIG. 8, and FIG. 9B shows an enlarged view around the punch hole 72.

  As shown in FIG. 9A, around the paper edge 71, the pixel value of the image data in the background area 82 is 255, and the pixel value of the image data in the shadow area 81 is 10. It can be seen that the image data of the white portion of the paper has a value smaller than 255 such as 230, 231 and the like. Therefore, the background area detection unit 51 can detect the background area 82 by searching for an area having a pixel value of 255.

  Further, as shown in FIG. 9B, around the punch hole 72, the pixel value of the image data in the background area 84 is 255, and the pixel value of the image data in the shadow area 83 is 10. And it turns out that the image data of the white background part of a sheet | seat is a value smaller than 255 like 231-233. Therefore, the background area detection unit 51 can detect the background area 84 by searching for an area having a pixel value of 255.

  Next, the shadow area detection unit 52 detects, from the image data from the signal conversion unit 41, an area where the pixel value is less than a preset shadow determination threshold as a shadow area having a density value equal to or greater than a certain value. (Step S102).

  For example, around the paper edge 71 as shown in FIG. 9A, a shadow area 81 with a pixel value of 10 is detected as a shadow area by the shadow area detection unit 52. Further, in the vicinity of the punch hole 72 as shown in FIG. 9B, a shadow region 83 having a pixel value of 10 is detected as a shadow region by the shadow region detection unit 52.

  Next, in the erasure area determination unit 53, among the shadow areas detected by the shadow area detection unit 52, an image that is within a preset number of pixels from the background area pixels detected by the background area detection unit 51. Is determined as an image of the shadow area to be erased (step S103).

  FIG. 10 shows an example of the relationship between the pixel value of the image data from the signal converter 41 and the data frequency when the original image shown in FIG. 8 is read. As shown in FIG. 10, it can be seen that the image data of the character image area of the original and the image data of the white paper of the original can be clearly determined with the shadow determination threshold (128) as a boundary. Further, it can be seen that the image data of the white paper sheet and the image data of the background image can be clearly determined with the background determination threshold as a boundary. However, it can be seen that the image data of the character image area of the document and the image data of the shadow area such as the paper edge 71 and the punch hole 72 are partially mixed and cannot be completely separated.

  Therefore, the shadow area detection unit 52 may determine that not only the shadow areas 81 and 83 as shown in FIG. 9 but also part of the image data of the character image area of the document is an image of the shadow area. is there. Therefore, the erasure area determination unit 53 determines only pixels in the shadow area existing around the pixels in the background area as erasure targets.

  For example, in the vicinity of the sheet edge 71 as shown in FIG. 9A, a shadow area 81 having a pixel value of 10 is detected by the erase area determination unit 53 as a shadow area to be erased. Further, in the vicinity of the punch hole 72 as shown in FIG. 9B, a shadow area 83 having a pixel value of 10 is detected as a shadow area to be erased by the erase area determination unit 53.

  Finally, the shadow area erasure processing unit 54 converts the image determined as the image of the shadow area to be erased by the erasure area determination unit 53 into preset white background data, thereby converting the shadow area around the background area. The image is erased (step S104). By the shadow area erasing process by the shadow area erasing processing unit 54, the shadow area caused by the paper edge 71 and the shadow area caused by the punch hole 72 are erased from the image shown in FIG. An image is obtained.

[Modification]
In the above embodiment, the case where the original is sequentially conveyed by the original conveying means such as DADF and the original image is read has been described. However, the present invention is not limited to this and is placed on the platen glass 25. The present invention can be applied in the same manner even when reading an original.

  For example, when a document placed on the platen glass 25 is read, a member having a reflectance similar to that of the reflection member 23 is used on the holding plate provided on the lid 40, so that It is possible to detect a defect area such as a punched hole in the placed document.

  In addition, if a similar configuration is used, not only a defect area such as a punch hole in a document placed on the platen glass 25 is detected, but also a document size of the document placed on the platen glass 25 is detected. Is also possible.

10 Image forming apparatus 11 CPU
12 Memory 13 Storage Device 14 Communication Interface (IF)
DESCRIPTION OF SYMBOLS 15 User interface (UI) apparatus 16 Scanner 17 Print engine 18 Control bus 20 Terminal apparatus 21 Original separation roll 22 Original conveyance roll 23 Reflective member 24 Ejection roll 25 Platen glass 26 Original tray 30 Network 31 Xenon lamp 32, 33 Reflection mirror 34 Connection Image lens 35 Photoelectric conversion element 40 Cover part 41 Signal conversion part 42 Image processing part 43 Dynamic range adjustment part 50 Main body part 51 Background area detection part 52 Shadow area detection part 53 Erase area determination part 54 Shadow area erasure processing part 60 Original 70 Image Reading unit 71 Paper edge 72 Punch hole 80 Image output unit 81 Shadow area 82 Background area 83 Shadow area 84 Background area

Claims (6)

Image reading means for reading the image of the document as an image signal by irradiating the document with light from a light source and reading the reflected light;
Conversion means for converting an image signal of a document read by the image reading means into image data expressed in a preset range;
An adjusting means for adjusting the converting means so that an image signal obtained by reading a white area of a printing paper used as a document by the image reading means does not become a maximum value in a range that can be expressed by image data;
A member arranged on the back side of the document read by the image reading unit and configured to saturate at least one color of the image signals read by the image reading unit to a maximum value that can be expressed by image data. A reflected member,
Detecting means for detecting a background area that is an area in which no document exists in the entire document area by detecting an area that is the maximum value of the range that can be expressed in the image data converted by the converting means;
An image reading apparatus comprising:   The shadow area image around the background area detected by the detection means is erased by converting the shadow area image whose density value is larger than a preset value into preset white background data. The image reading apparatus according to claim 1, further comprising an erasing unit that performs the erasing unit.   The image reading apparatus according to claim 2, further comprising a determination unit that determines an image within a preset number of pixels from the pixels in the background area detected by the detection unit as an image in the shadow area.   3. The image reading apparatus according to claim 2, further comprising: a determination unit that determines, as an image in the shadow region, an image that is continuously adjacent within a preset number of pixels from the pixels in the background region detected by the detection unit. . Image reading means for reading the image of the document as an image signal by irradiating the document with light from a light source and reading the reflected light;
Conversion means for converting an image signal of a document read by the image reading means into image data expressed in a preset range;
An adjusting means for adjusting the converting means so that an image signal obtained by reading a white area of a printing paper used as a document by the image reading means does not become a maximum value in a range that can be expressed by image data;
A member arranged on the back side of the document read by the image reading unit and configured to saturate at least one color of the image signals read by the image reading unit to a maximum value that can be expressed by image data. A reflected member,
Detecting means for detecting a background area that is an area in which no document exists in the entire document area by detecting an area that is the maximum value of the range that can be expressed in the image data converted by the converting means;
The shadow area image around the background area detected by the detection means is erased by converting the shadow area image whose density value is larger than a preset value into preset white background data. Erasing means to perform,
An image forming apparatus comprising: an image output unit that outputs a document image after an image in a shadow region around a background region is erased by the erasing unit. Irradiating the document with light from a light source and reading the reflected light to read the image of the document as an image signal;
Converting the image signal of the read document into image data expressed in a preset range;
And detecting a background area that is an area in which no document exists in the entire document area by detecting an area that is the maximum value that can be expressed in the converted image data. Program.

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