JP6409365B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an image of a document. More specifically, the present invention relates to a technique for determining the characteristics of a read image.

  2. Description of the Related Art Conventionally, a technique for reading an image of a document and determining image characteristics based on the read image is known. For example, in Patent Document 1, color image data and monochrome image data are generated based on a read image, it is determined whether the read image is a color image or a monochrome image, and color image data and A configuration for transmitting either one of monochrome image data to an external device is disclosed.

JP 2006-261927 A

  However, the conventional technique described above has the following problems. That is, it takes time to determine the characteristics of the image. This determination delay may delay the completion of the job, and the determination method needs to be improved.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a technology that can expect image characteristic determination in a short time for an image reading apparatus that determines image characteristics.

  An image reading apparatus for solving this problem includes a reading unit that reads an image of a document, and a control unit. The control unit reads the document image by the reading unit, and reads the document. A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a type determination target area smaller than a single document area is satisfied, and the determination process satisfies the specific condition. If it is determined that there is not, the type of the original is determined using the first area, which is an area of one original in the read image read by the reading process, as the determination area. If it is determined that a specific condition is satisfied, a determination process for determining a document type using a second area smaller than the first area as a determination area in the read image read by the reading process; To perform It is characterized.

  The image reading apparatus disclosed in this specification reads an image of a document and determines the type of the document based on the read image. At that time, it is determined whether or not a specific condition that is a condition for making a determination area that is a determination target area of the document type smaller than a single document area is satisfied, and it is determined that the specific condition is not satisfied. In this case, the type of the original is determined using the first area, which is the area of one original in the read image, as the determination area. On the other hand, when it is determined that the specific condition is satisfied, the document type is determined using the second area smaller than the first area in the read image as the determination area.

  Specific conditions include, for example, a condition that does not affect the determination accuracy even if the determination region is reduced (the first region may remain the same, but it does not affect the determination accuracy and positively shortens the determination time). Conditions that can cause inconvenience if the judgment area is large (conditions that reduce the possibility of inconvenience by shortening the judgment time because inconvenience may occur if the first area remains unchanged). is there. Examples of the former include black and white reading, reading of a document after a predetermined page, and acceptance of a copy instruction. As the latter, for example, the interval between sheets is equal to or less than a predetermined value, the memory capacity is insufficient, and the output of a specific format is applicable. The second area includes, for example, an area in which the margin area of the document and an area that becomes a margin at the output destination are deleted, and an area in which no content such as characters, images, and figures is included in the preceding document. Applicable.

  In other words, when the image reading apparatus disclosed in this specification determines that a specific condition is satisfied, the determination area that is the determination target of the document type is a small area. I can expect. That is, when the second area is set as the determination area, the amount of processing required for the determination is smaller than when the first area is set as the determination area. Therefore, compared with the case where the first area is uniformly used for determination, it can be expected to determine the type of document in a short time.

  The control unit may include a plain color determination for determining whether or not the original is plain in the determination of the type of the original.

  Further, the control unit determines that the original is not plain when the ratio of the area determined to be non-solid in the original exceeds a plain threshold in the plain determination, and the determination processing is performed. When it is determined that the specific condition is satisfied, the solid threshold may be set smaller than that when the determination process determines that the specific condition is not satisfied. The plain threshold is a threshold for determining a plain plain document, and is, for example, the ratio of pixels of a color other than the ground color allowed for a plain document. Decreasing the blank threshold value makes it difficult to determine that the document is a blank document. That is, even if the determination area is reduced, there is a low possibility that a non-plain original will be erroneously determined as a plain original.

  The control unit may include a color determination for determining the color of the document in the determination of the document type. In the color determination, it is determined whether the read image is, for example, color, gray scale, or black and white.

  In addition, the control unit determines that the document is color when the ratio of the area determined to be color in the document exceeds a color threshold in the color determination, and the determination process includes When it is determined that the specific condition is satisfied, the color threshold value may be made smaller than when the determination process determines that the specific condition is not satisfied. The color threshold is a threshold determined to be a color document, and is, for example, the minimum ratio of color pixels included in the color document. Decreasing the color threshold makes it easier to determine that the document is a color document. That is, even if the determination area is reduced, there is a low possibility that a color document is erroneously determined as a grayscale document or a monochrome document.

  Further, the control unit includes a plain color determination for determining whether or not the original is plain and a color determination for determining the color of the original in the determination of the type of the original. When either one of the color determinations is completed, it is determined that the specific condition is satisfied. In the determination process, the region up to the timing at which the specific condition is determined in the determination process is determined as the first area. It is good to complete the determination which has not been completed among the said plainness determination and the said color determination by setting it as 2 area | regions. When either one of the plain color determination and the color determination is completed, it may be considered that the other determination is also completed. For example, there is a case where the determination result of the other is fixed, or there is no need to continue the determination of the other. For this reason, it is preferable to complete the determination by setting the target area in the other determination as the determination area by the timing of the completion of one determination.

  In the determination process, the control unit determines that the specific condition is satisfied when the reading unit reads the document by black and white reading. In the determination process, the control unit determines whether the read image read by the reading process Of these, a region obtained by removing a region corresponding to at least a part of the peripheral region on at least four sides may be set as the second region. There is a high possibility that a document to be scanned in black and white is a text image. For this reason, for example, the areas corresponding to the header and footer areas have little influence on the determination accuracy even if they are not determined. In addition, there is a high possibility that there are blank areas at the left and right edges of the document. For this reason, the region from which these regions are removed is used as the second region, so that the determination can be completed early while suppressing a decrease in the determination accuracy.

  In the determination process, the control unit determines whether or not the specific condition is satisfied based on a part of read images of a plurality of read images in one job. In the determination process, When it is determined in the determination process that the specific condition is satisfied, an area including the content in the partial read image may be set as the second area for the remaining read images of the plurality of read images. . There is a high possibility that the originals in one job are of the same type. That is, based on the image of the preceding document, it is possible to predict an area in which the content is included in the subsequent document. Therefore, it is determined whether or not a specific condition is satisfied based on a part of the scanned images of the plurality of scanned images. When the specific condition is satisfied, an area in which the content is included in the part of the scanned images is By using the second region of the subsequent read image, the determination can be completed at an early stage while suppressing a decrease in the determination accuracy. For example, when a predetermined number of documents are read, it is determined that a specific condition is satisfied, and an area having content in at least one of them is set as the second area for the remaining documents. Further, for example, when there are more than a specified number of read images having contents in a specific area, it is determined that the specific condition is satisfied, and the specific area is set as the second area in the remaining document.

  The image reading device disclosed in this specification includes a printing unit that prints an image on a recording sheet, and the control unit prints the printing unit based on the read image read by the reading process. In the determination process, the second region may be determined based on the margin setting size of the recording paper when the print unit is used for printing in the printing process. When an image to be printed is read, the utility value is low even if a determination is made for an area set as a margin on the recording paper. Therefore, by making the area where the margin setting portion of the recording paper is removed as the second area, it is possible to complete the determination at an early stage while suppressing a decrease in the determination accuracy.

  In the determination process, the control unit may determine that the specific condition is not satisfied when the size of the document is a prescribed size. There is a high possibility that a standard-size original for photography, such as the L and 2L versions, is a photographic original. In addition, a photographic manuscript has no margin or header area, and there is a high possibility that the entire sheet has content. For this reason, when the size of the document is a prescribed size estimated to be a photographic document, the determination accuracy may be significantly reduced if the determination region is the second region. Therefore, it is preferable not to set the determination area as the second area in a document of a prescribed size.

  The image reading apparatus disclosed in the present specification further includes a storage unit, and the control unit satisfies the specific condition when the free space of the storage unit is less than a prescribed amount in the determination process. It is good to judge. If the entire area of one original is set as the determination area, it takes a long time to store the read image in the memory, and the memory tends to become full. For this reason, when the free space of the memory is small, it is preferable to use the second area as the determination area to reduce the possibility of the memory being full.

  Further, the control unit executes an output process for outputting an image file based on the read image read by the reading process, and in the determination process, the format of the image file output by the output process is a plurality of images. May be determined to satisfy the specific condition when the specific format is stored in one file. In the case of a format in which a plurality of images are stored in one file, it is necessary to store all read images stored in one file, and there is a high possibility that the memory will be full. Therefore, it is preferable to reduce the amount of memory used for determination using the second area as the determination area.

  The image reading apparatus disclosed in the present specification further includes a transport unit that transports a document. In the determination process, the control unit determines whether the document continuously transported by the transport unit is between the documents. When the distance is shorter than the distance threshold, it may be determined that the specific condition is satisfied. When the distance between the continuously conveyed documents is short, there is a possibility that the succeeding document reaches the reading position before the determination for the preceding document is completed. In this case, the reading of the subsequent document is awaited until the determination for the preceding document is completed. In order to reduce such a waiting time, it is preferable to complete the determination early with the determination region as the second region. The distance threshold is, for example, a distance that reaches or may reach the reading start timing of the subsequent document before the determination of the preceding document is completed. The document having the determination area as the second area may be a preceding document, a subsequent document, or both documents.

  Further, the control unit may execute midway change processing for changing the determination area in the middle of determination of one original. By making it possible to change the determination area even during the determination of one original, the possibility of completing the determination earlier is increased.

  The image reading apparatus disclosed in the present specification further includes a conveyance unit that conveys a document, and the control unit determines the determination area between the documents of the document continuously conveyed by the conveyance unit. It is preferable to execute a paper interval determination process. If the determination area is changed during the determination of one original, the control becomes complicated, such as changing the determination threshold, and the determination accuracy may be reduced. Therefore, these problems can be avoided by determining the judgment area between documents.

  According to the present invention, a technology that can expect image characteristic determination in a short time is realized for an image reading apparatus that determines image characteristics.

1 is a perspective view showing a schematic configuration of an MFP according to an embodiment. 2 is a cross-sectional view illustrating a schematic configuration of an image reading unit of the MFP. FIG. 2 is a block diagram illustrating an electrical configuration of the MFP. FIG. 6 is a flowchart illustrating a procedure of read job processing according to the present embodiment. It is a flowchart which shows the procedure of a determination reading process. It is a flowchart which shows the procedure of the determination area initialization process. It is explanatory drawing which shows the example of a document original. It is explanatory drawing which shows the example of the position of the content in a document. It is a flowchart which shows the procedure of a determination area | region setting process.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying a reading apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the present embodiment, the present invention is applied to a multi function peripheral (MFP) having an image reading function.

  As shown in FIG. 1, the MFP 100 according to this embodiment includes an image forming unit 10 that prints an image on a sheet, an image reading unit 20 that reads an image of a document, and an operation that displays an operation status and accepts an input operation by a user. Panel 40. The image forming method of the image forming unit 10 may be an electrophotographic method or an ink jet method. The image forming unit 10 is an example of a printing unit.

  As shown in FIG. 2, the image reading unit 20 includes a reading head 21 and an ADF (automatic document feeder) 22. The reading head 21 optically reads an image and is movable in the direction of arrow A in FIG. The ADF 22 is provided above the reading head 21 so as to be openable and closable with respect to the main body. As shown in FIG. 2, the ADF 22 has a document tray 28 and a document discharge tray 29. The ADF 22 conveys documents set on the document tray 28 one by one along a predetermined path 26 and discharges them to the document discharge tray 29. Further, the image reading unit 20 is provided with a document detection unit 27 that outputs different signals according to the presence or absence of documents stored in the document tray 28. The ADF 22 is an example of a transport unit.

  The image reading unit 20 reads the image of the document while relatively moving the document and the reading head 21. The image reading unit 20 of this embodiment is capable of color reading. If the document is set on the document tray 28, the image reading unit 20 fixes the reading head 21 and moves and reads the document using the ADF 22. If the document is not set on the document tray 28, the reading head 21 is moved to read the document on the flat bed glass 25. MFP 100 generates image data based on the read document image. The image reading unit 20 is an example of a reading unit.

  When a plurality of documents are collectively set on the document tray 28, the MFP 100 according to the present embodiment continuously reads one document at a time until the documents on the document tray 28 run out, and reads the plurality of documents in one job. Of the manuscript. Based on the output signal of the document detection unit 27, the MFP 100 detects that there are no more documents on the document tray 28. In MFP 100, when a plurality of documents are continuously conveyed using ADF 22, a distance is generated between the documents. The distance between the originals is not necessarily constant. For example, the distance between the originals is short when the size in the original conveyance direction is small, and is long when the size in the original conveyance direction is large.

  As shown in FIG. 1, the operation panel 40 includes a liquid crystal display 41 and a button group 42 including a start key, a stop key, a numeric keypad, and the like. MFP 100 accepts an instruction input from the user via operation panel 40.

  Next, the electrical configuration of the MFP 100 will be described. As illustrated in FIG. 3, the MFP 100 includes a controller 30 including a CPU 31, a ROM 32, a RAM 33, an NVRAM (nonvolatile RAM) 34, and an ASIC 35. The MFP 100 includes an image forming unit 10, an image reading unit 20, a network interface (IF) 37, a USB interface (IF) 38, and an operation panel 40, which are electrically connected to the controller 30. ing.

  The ROM 32 stores various control programs for controlling the MFP 100, various settings, initial values, and the like. The RAM 33 is used as a work area from which various control programs are read, or as a storage area for temporarily storing data. The CPU 31 controls each component of the MFP 100 according to the control program read from the ROM 32 while storing the processing result in the RAM 33 or the NVRAM 34. The RAM 33 or NVRAM 34 is an example of a storage unit.

  The CPU 31 is an example of a control unit. The controller 30 may be a control unit, and the ASIC 35 may be a control unit. Note that the controller 30 in FIG. 3 is a collective term for the hardware used for controlling the MFP 100 such as the CPU 31, and does not necessarily represent a single piece of hardware that actually exists in the MFP 100.

  The network IF 37 is hardware for communicating with a device connected via a network using a LAN cable or the like. The USBIF 38 is hardware for communicating with a device connected via a USB cable or the like.

  The MFP 100 according to this embodiment accepts job instructions including reading operations such as a scan instruction, a copy instruction, and a FAX transmission instruction. When the MFP 100 receives an instruction for a job including a reading operation, the MFP 100 reads the original set on the image reading unit 20 one by one, and executes the operation of the instructed job based on the acquired image data.

  The MFP 100 accepts designation of whether or not to perform blank page removal at the time of output and designation of a reading color in a job setting including a reading operation. When the MFP 100 receives the blank page removal designation, the MFP 100 does not output a page that is regarded as a blank page in the document. In other words, pages that are considered blank are packed and output. Therefore, when the MFP 100 receives a job for which execution of blank page removal is specified, the MFP 100 executes a plain color determination operation for determining whether or not each read original is a plain original. The plain color determination operation will be described later.

  Then, the MFP 100 outputs image data based on a document determined not to be a plain document in the plain determination operation, and does not output image data based on a document determined to be a plain document. A plain document is a blank or colored plain document that has no content. For example, in the case of a scan instruction, a transmission image file is generated with image data that does not include a plain original. If it is a copy instruction, a copy of only a document other than a plain document is generated. If it is a FAX transmission instruction, an image excluding a plain original image is transmitted.

  On the other hand, when a specified job that does not execute blank page removal is received, the blank determination operation is not executed. Then, regardless of the content of the image, the image data is output according to the job setting.

  In addition, the MFP 100 according to the present embodiment accepts, for example, selection from four types of color designation for reading, that is, color reading, gray scale reading, black and white reading, and automatic color reading. When the MFP 100 receives a job for which color reading is designated as the reading color designation, the MFP 100 outputs image data of a color image including color information. When a job for which grayscale reading is specified is received, image data including gradation information in an achromatic color is output. When a job for which black and white reading is specified is received, binary image data is output.

  When the MFP 100 accepts a job for which automatic color reading is designated, the read original is a color original including a color image, a gray scale original including a gradation with an achromatic image, or two gradations. A color determination operation for determining whether the original is a monochrome document is executed, and image data based on the color determination result is output. The color determination operation will be described later.

  In other words, the MFP 100 may perform at least one of the plain color determination operation and the color determination operation based on the received job instruction. The plain color determination operation or the color determination operation is an example of a document type determination operation.

  The MFP 100 may determine the type of document for image data generated by a reading operation. In that case, MFP 100 executes at least one of plain color determination and color determination of the original image data that is generated by reading one original document. Then, even when there are a plurality of documents in one job, MFP 100 starts reading the next one document after both the reading operation and the determination operation are completed for one document. Note that the reading operation and the determining operation may be executed in parallel or may not be executed in parallel.

  Here, the time required for the MFP 100 to complete the document type determination operation is likely to be longer as the size of the image data to be determined is larger. In view of this, the MFP 100 according to the present embodiment is smaller than the area of one original when the determination area, which is the determination target area of the type of original, satisfies a specific condition that is a condition for making it smaller than the area of one original. The document type is determined based on the area. Then, MFP 100 uses the determination result for the small area as the determination result for the document. The time required for determining the type of document based on an area smaller than the area of one original is shorter than the time required for determining the type of original based on the entire area of one original. Probability is high. Details of the specific conditions will be described later.

  Note that the MFP 100 may perform both the plain color determination operation and the color determination operation, or may perform only one of them. When performing both determination operations, MFP 100 according to the present embodiment sets the determination area as a common area. That is, as described above, when the determination area is smaller than the area of one document, both the determination area for the plain color determination operation and the determination area for the color determination operation are small areas.

  Here, the determination process of the solid color determination and the color determination and each determination threshold value will be described. When the reading operation is started, the MFP 100 according to the present embodiment causes the image reading unit 20 to perform color reading of a document, and acquires RGB format image data including color information. Then, the MFP 100 converts the acquired RGB format image data to generate YCbCr format image data. In the YCbCr format image data, the Y component is a luminance component that represents luminance, and the Cb component and the Cr component are color difference components that represent color differences of different colors.

  In the plain color determination, the MFP 100 divides the image data into blocks of, for example, 100 pixels × 100 pixels in order from the generated part. Then, MFP 100 determines for each block whether it is a plain block or a non-solid block. For example, if the ratio of pixels whose luminance component value is not the mode value in the block is greater than or equal to the plain pixel threshold based on the Y value of all the pixels in the block, the MFP 100 is a plain block. Is determined. On the other hand, if the ratio of pixels whose luminance component value is not the mode value in the block is less than the plain pixel threshold, the MFP 100 determines that the block is a plain block.

  MFP 100 determines that the original is not a plain original, that is, a plain original, when the ratio of the non-plain blocks in all the blocks in the determination area exceeds a predetermined plain block threshold. That is, even during reading, if the number of blocks determined to be plain is equal to or greater than the plain block threshold for all blocks, MFP 100 determines that the document is a plain document. The plain pixel threshold and the plain block threshold are determination thresholds in the plain judgment, and are examples of the plain threshold.

  On the other hand, it is determined that the original is a plain original when the ratio of the number of plain plain blocks is less than the plain block threshold. For this reason, MFP 100 does not determine that the document is a plain document until almost the entire determination area of the document has been read. If it is determined that the document is a plain document or it is determined that the document is a plain document, the MFP 100 completes the plain document determination.

  In the color determination process, the MFP 100 divides the image data into blocks of, for example, 100 pixels × 100 pixels in order from the generated portion. Then, the MFP 100 determines whether each block is a color block, a gray block, or a monochrome block. The MFP 100 determines whether the block is an achromatic block based on the average value of the Cb values and the average value of the Cr values of all the pixels in the block. Specifically, if both average values are within a predetermined range, it is determined that the block is an achromatic color block. If the ratio of pixels that are not achromatic colors is equal to or greater than the color pixel threshold, MFP 100 determines that the block is a color block.

  If the MFP 100 determines that the block is an achromatic color block, based on the Y value, the ratio of the total number of very dark pixels and very bright pixels to the total number of pixels in the block It is determined whether or not exceeds a predetermined ratio. MFP 100 determines that the block is a black and white block when the total number exceeds a predetermined ratio, and determines that the block is a gray block when the total number does not exceed the predetermined ratio.

  MFP 100 determines that the original is a color original when the proportion of the color blocks in all the blocks in the determination area exceeds a predetermined color block threshold. That is, even during reading, if the number of blocks determined to be color blocks is equal to or greater than the color block threshold value for all blocks, the document is determined to be a color document. The color pixel threshold value and the color block threshold value are determination threshold values in color determination, and are examples of color threshold values.

  Unless it is determined that the original is a color original in the middle of reading, the MFP 100 further executes color determination processing after the original determination area has been read. The MFP 100 determines, for all the pixels in the determination area, whether or not many pixels are occupied by a color close to an achromatic color based on the mode value of the Cb value and the mode value of the Cr value. If at least one of the mode value of the Cb value and the mode value of the Cr value is not within the predetermined range, the MFP 100 determines that the document is a color document.

  Then, when many pixels of the document are close to achromatic color and the ratio of gray blocks in all blocks in the determination area exceeds a predetermined range, MFP 100 determines that the document is a grayscale document. Is determined. On the other hand, if many pixels of the document are close to achromatic and the gray block ratio does not exceed the predetermined range, the document is determined to be a monochrome document. If it is determined as one of a color original, a gray scale original, and a black and white original, MFP 100 completes the color determination.

  Next, a reading job processing procedure for realizing job operations including reading in the MFP 100 will be described with reference to a flowchart of FIG. This reading job process is executed by the CPU 31 when a job execution instruction including reading is received.

  In the reading job process, the MFP 100 first determines whether there is a blank sheet removal designation (S101). The blank page removal designation may be designated for the job or may be set for the MFP 100. If the MFP 100 determines that the blank page removal designation has been received (S101: YES), the MFP 100 determines to perform a plain color determination process for determining whether the document being read is a plain document (S102). On the other hand, if it is determined that no blank page removal designation has been received (S101: NO), the MFP 100 determines not to execute the plain color determination process.

  Further, the MFP 100 determines whether or not designation of automatic color reading is accepted in accordance with the received job instruction (S104). That is, if the job does not accept any of color reading designation, grayscale reading designation, and monochrome reading designation, the MFP 100 determines that the automatic color reading designation has been accepted. If the MFP 100 determines that the designation of automatic color reading has been received (S104: YES), the MFP 100 determines to perform color determination processing for determining the color of the document being read (S105). On the other hand, when it is determined that the designation of automatic color reading is not accepted (S104: NO), the MFP 100 determines not to execute the color determination process.

  Next, the MFP 100 determines whether or not it is determined to execute the determination process in at least one of S102 and S105 (S107). If it is determined not to perform the determination process (S107: NO), the MFP 100 executes only the reading operation without executing the determination process.

  That is, the MFP 100 executes a one-sheet reading operation (S110), and determines whether there is a next document (S112). If there is a next original (S112: YES), the MFP 100 reads the next original. If there is no next original (S112: NO), the MFP 100 executes the output instructed by the job (S114) and ends the reading job process.

  On the other hand, if it is determined that at least one of the determination processes is determined to be performed (S107: YES), the MFP 100 executes a determination reading process for executing the process determined to be performed (S115).

  Next, the determination reading process of S115 will be described with reference to the flowchart of FIG. This determination reading process is a reading process in the case where at least one of the plain determination and the color determination is performed. Note that the MFP 100 executes plain color determination and color determination for the document being read in parallel with the reading operation. The solid color determination and the color determination include processing parts common to both, but are independent processes.

  In the determination reading process, the MFP 100 first executes a determination area initialization process (S201). The determination area initialization process is a process for determining an initial value of the determination area in the solid color determination or the color determination.

  Next, the determination area initialization process of S201 will be described with reference to the flowchart of FIG. In this determination area initialization process, the MFP 100 first determines whether or not a non-limiting condition is satisfied (S301). The non-limiting condition is a condition in which the determination area is not limited and the area of one document is used. That is, when MFP 100 determines that the non-limiting condition is satisfied, MFP 100 determines that the specific condition is not satisfied. A non-limiting condition is an example of a condition for determining that a specific condition is not satisfied.

  Non-limiting conditions include, for example, standard sizes for photographs such as L and 2L originals. For example, the MFP 100 acquires the size of the read document based on the edge position of the read image, and determines whether the size of the document is a standard size for photographs. Further, for example, when “photograph” is designated in the read image quality setting, the MFP 100 may determine that the image is a standard size for a photo. A photo manuscript is likely to have no margins around it, and it is highly likely that the entire manuscript has content. For this reason, if the size of the document is a specified size, the determination accuracy may be significantly reduced if the determination region is limited.

  If the MFP 100 determines that the non-limiting condition is satisfied (S301: YES), the MFP 100 sets the determination area as the entire area of one original (S303). Further, the MFP 100 determines a determination threshold value as a predetermined threshold value for all regions (S304). The determination threshold includes a plain threshold for solid color determination and a color threshold for color determination. Note that S303 and S304 may be reversed.

  On the other hand, when it is determined that the non-limiting condition is not satisfied (S301: NO), the MFP 100 determines whether the limiting condition is satisfied (S306). The limiting condition is a condition for determining whether or not the initial value of the determination area is a limited area that is smaller than the entire area of one document. The limiting condition is an example of a specific condition. The process of S306 is an example of a determination process. Further, the entire area of one original is an example of the first area, and the limited area is an example of the second area.

  Next, limiting conditions will be described. The MFP 100 has one or more limiting conditions, and determines whether or not to limit the determination area using one or more of the limiting conditions provided. The limiting condition includes, for example, an example of a condition that does not affect the determination accuracy even if the determination area is small, and an example of a condition that can cause inconvenience if the determination area is large. As the former limiting conditions, for example, it is instructed that the job accepts the designation of black-and-white reading, and that the document being read is a document including a plurality of documents, and that the document being read is a document after a predetermined page in the job. Corresponds to a copy job. The latter limiting condition corresponds to, for example, a scan job in which a specific output format is specified.

  For example, a job manuscript for which designation for black and white reading has been received is highly likely to be a document manuscript. In the case of a document manuscript, as shown in FIG. 7, there is a high possibility that there are areas 62 without content on the four sides of the manuscript 61. For example, even if the header area having the width S1 and the footer area having the width S2 are excluded from the determination target, it can be estimated that the influence on the determination accuracy is small. In addition, there is a high possibility that the left side area with the width S3 and the right side area with the width S4 have margins. Even if these left and right margin areas are excluded from the determination targets, it can be estimated that the influence on the determination accuracy is small.

  Therefore, MFP 100 sets a determination area for a document that satisfies this limitation condition as a central area excluding the four edge areas, with the limitation condition that the document is a job that has been designated for black and white reading. For example, the determination is not made within the range of 30 mm from the document edges on all sides. Note that when the designation of black and white reading is received, the color determination process is not executed, so this limiting condition is applied to the plain color determination process.

  Further, for example, when a plurality of originals are collectively set in the ADF 22 and the originals are accepted as one job, the MFP 100 generates image data for each original and determines the plain color for each original. Processing and color determination processing are executed. In many cases, a plurality of originals in one job share the same content arrangement. Therefore, MFP 100 determines a determination area for the remaining originals of the job based on the image of the read original in one job.

  For this reason, in a job including a plurality of documents, MFP 100 stores the arrangement of contents for each document. For example, as shown in FIG. 8, the position of a rectangular range 65 including all contents in the read document 64 is acquired. Then, the widths T1, T2, T3, T4 from the four sides of the document in the outer frame area 66 not included in the rectangular area 65 are stored. For example, the rectangular area 65 of the preceding document is set as a determination area in the subsequent document. For example, an area having content in at least one of the preceding predetermined documents is set as a determination region of the document being read.

  Further, for example, it is assumed that the area including the content is common in a predetermined number of images or more, and the MFP 100 uses the common area as a determination area for a document after a predetermined sheet of the same job. Also good. If there is content in an area common to the preceding predetermined document, that area is set as a determination area of the document being read. For example, if the rectangular area 65 is common to the first two pages, the MFP 100 sets the rectangular area 65 as the determination area for the third and subsequent pages.

  Further, for example, instead of acquiring the rectangular range 65, the MFP 100 may store the position of a block determined as a non-solid block or the position of a block determined as a color block. Then, when there is a non-solid block or a color block at a common position in a predetermined number of documents, the MFP 100 determines that the limiting condition is satisfied for the subsequent documents in the job, and the area including the common position is determined. Is a determination area. Note that each time a single document is determined, the determination area may be gradually reduced in subsequent documents depending on the degree of overlap of the content positions.

  Further, in a manuscript that has received a copy job, the read image data of the entire area is not necessarily the target of printing. That is, the area used for printing in the image forming unit 10 may be a part of the image data read by the image reading unit 20. For example, if a margin is set for the recording paper in the print settings, the image data in the area corresponding to the margin is not used for printing even if it is read. In view of this, the MFP 100 uses a copy job as a limiting condition, and sets an area of the original image excluding a portion corresponding to the margin setting of the recording paper as a determination area. Further, when a print range is specified in the original, an area corresponding to the print range may be set as the determination area.

  Further, for example, in the scan job, the MFP 100 selects, as an output image file format, a format in which one image is one image file and a format in which a plurality of images are combined into one image file. Accept. In a format in which a plurality of images are made into one image file, it is necessary to store data of the plurality of images before the image file is output.

  Therefore, the MFP 100 makes the determination area smaller than the entire area on the condition that the format specified by the scan instruction is a specific format in which a plurality of images are used as one image file. For example, the MFP 100 sets a central area of the original image excluding the four edge areas as the determination area. The MFP 100 reduces the amount of memory used in the determination process by reducing the determination area. The specific format corresponds to, for example, the PDF format or the XPS format.

  When the MFP 100 determines that the limiting condition is satisfied in the determination area initialization process of FIG. 6 (S306: YES), the MFP 100 sets the determination area as the limited area (S308). Then, the MFP 100 determines a determination threshold value (S309). In S309, the MFP 100 reduces the determination threshold when the determination area is limited to be smaller than the threshold for all areas set in S304, and reduces the possibility of erroneous determination by bringing the determination to the safe side. Let Therefore, it is possible to reduce a problem that an image that should be output is not output or an image that should be output as a color image is output as a grayscale image or a binary image. Note that S308 and S309 may be reversed. After S304 or S309, the determination area initialization process ends. The process of S308 is an example of a paper interval determination process.

  Specifically, in the plain color determination, the MFP 100 makes at least one of the above-described blank pixel threshold value and the plain color block threshold value smaller than the threshold value of S304 so that it is difficult to determine a plain document. Further, in the color determination, the MFP 100 makes it easy to determine that the document is a color document by making at least one of the color pixel threshold and the color block threshold smaller than the threshold in S304.

  For example, in the case of a document with a biased content arrangement, there is a possibility that the ratio of non-solid blocks and color blocks included in the determination area may be reduced by limiting the determination area. Since the MFP 100 according to the present embodiment is less likely to be determined as a plain document by reducing the blank threshold, the possibility of not outputting a document with content is reduced. In addition, since the MFP 100 can easily determine that the document is a color document by reducing the color threshold value, the possibility that the document having a small color portion is determined to be a color is increased.

  Returning to FIG. 5, after the determination area initialization process, the MFP 100 starts reading one original and a determination process based on the determination area determined for the original (S203). In S <b> 203, if a document is set on the ADF 22, the MFP 100 starts transporting the document using the ADF 22 and sequentially reads the documents one by one. If no document is set on the ADF 22, the MFP 100 moves the reading head 21 to read. Further, as described above, execution of the determination process is started based on the read image data. The process of S203 is an example of a reading process and a determination process.

  Then, the MFP 100 determines whether or not a change condition for changing the determination area is satisfied (S205). That is, when MFP 100 determines that the change condition for changing the determination area to a smaller determination area is satisfied during the determination after starting determination based on the determination area determined in the determination area initialization processing ( S205: YES), determination area setting processing for resetting the determination area is executed (S206).

  Here, the change condition will be described. The MFP 100 includes one or more change conditions, and determines whether to reset the determination area using one or more change conditions among the provided change conditions. The change condition includes a condition in which the determination area is desired to be further reduced due to a change in the state of MFP 100 during execution of the determination process. As a change condition, for example, the free space of the memory is less than a prescribed amount, the distance between documents in reading using the ADF 22 is equal to or less than a distance threshold, and both plain color determination and color determination are being executed. Applicable to completion of judgment. The change condition is an example of a specific condition.

  For example, when the free space of the memory decreases, it is desirable to complete the determination at an early stage in order to reduce the possibility of the memory becoming full. If the determination is completed early, the possibility that the job can be completed early and the memory can be released early increases. Therefore, the MFP 100 determines that the change condition is satisfied when the free space of the memory is less than the predetermined specified amount, and executes the determination area setting process.

  Further, for example, when the distance between documents in reading using the ADF 22 is equal to or less than the distance threshold, the time required for each determination process is short. For example, the MFP 100 includes a sensor that outputs a signal corresponding to the presence or absence of a document in the path 26 of the ADF 22, and acquires a distance between documents passing through the path 26 according to the output of the sensor. Further, for example, the MFP 100 may estimate the distance to the next document based on the size of the conveyed document.

  That is, if the determination takes a long time with the distance between the originals being short, the subsequent original may reach the reading start position before the determination for the previous original is completed. Then, in order to wait for the completion of the determination and start reading the subsequent document, it is necessary to delay the start of reading the subsequent document, which may cause a disadvantage that the time required for reading becomes longer as a whole. Therefore, MFP 100 determines that the change condition is satisfied when the distance between the originals conveyed by ADF 22 is short, and executes determination area setting processing.

  In the change condition depending on the distance between documents, the document whose determination area is to be changed may be a preceding document, a subsequent document, or both documents. For example, when the subsequent document reaches the reading start position, the determination area of the preceding document may be an area up to the position determined at that time. Further, for example, a portion of the subsequent document that is read before the determination of the preceding document is completed may not be the determination region of the subsequent document. Further, with respect to the subsequent document, the determination of the preceding document may be continued outside the determination area until the predetermined width is read from the head, and the determination of the preceding document may be terminated when the predetermined width is reached.

  When the MFP 100 receives both automatic color reading designation and blank page removal designation in response to a job instruction, the MFP 100 executes color determination processing and plain color determination processing in parallel. For example, when one of the determinations is completed, it may be determined that the other determination is also completed. For example, it is not necessary to continue the color discrimination when it is determined that the color is plain in the plain color determination process. Further, for example, if the setting is made so that a color plain original is not determined to be blank, and it is determined as color or gray scale in the color determination process, it can be determined that it is not blank. Therefore, when both the color determination process and the plain color determination process are being executed and one of the determination results is obtained, it is determined that the change condition is satisfied, and the determination area setting process is executed.

  Next, the determination area setting process executed in S206 of FIG. 5 will be described with reference to the flowchart of FIG. This determination area setting process is executed when a change condition for changing the determination area is satisfied during reading of one original, and the determination area is reset.

  In the determination area setting process, the MFP 100 first determines whether or not the satisfied change condition is an end condition for ending the determination process (S401). For example, the satisfied change condition is that the distance between the originals is equal to or less than the distance threshold value, and the setting of the process in the change condition ends the determination process for the original whose determination is being performed at that time. If set, the change condition is an end condition. If it is determined that the end condition is satisfied (S401: YES), the determination is completed based on the determination results up to that point (S402), and the determination area setting process is terminated.

  For example, if the satisfied change condition is that both the color determination process and the plain color determination process are executed and one of the determinations is completed, the change condition is an end condition. For example, when it is determined that the document is a plain document in the plain color determination process, the color determination is terminated, and the area determined up to that point is set as the determination area.

  On the other hand, if it is determined that the change condition is not an end condition (S401: NO), it is determined whether or not to change the determination area (S404). For example, if the determination area is already small and should not be further reduced, the MFP 100 determines not to change the determination area (S404: NO), and ends the determination area setting process.

  If MFP 100 determines that the determination area is to be changed based on a change condition other than the end condition (S404: YES), MFP 100 sets the determination area to a smaller change area (S406). Then, a determination threshold value is determined according to the change area (S407). That is, as in S309, the determination threshold is further reduced. Then, the determination area setting process ends. The process of S406 is an example of a midway change process.

  Returning to FIG. 5, after the determination area setting process of S206 or when it is determined that the change condition is not satisfied (S205: NO), the MFP 100 determines whether the determination is completed (S208). For example, if the determination process being executed is a plain color determination process and the ratio of the solid color blocks exceeds the solid color block threshold, the MFP 100 determines that the solid color determination has been completed. For example, if the determination process being executed is a color determination process and the ratio of color blocks exceeds the color block threshold, the MFP 100 determines that the color determination has been completed. Alternatively, the MFP 100 determines whether the determination for the determination area is completed and a determination result is obtained. Note that when both determination processes of the plain color determination and the color determination are executed, the MFP 100 determines that the determination is completed when both determination processes are completed in S208.

  If the determination process being executed has not been completed (S208: NO), the MFP 100 returns to S205 to continue the reading and determination while determining the change condition.

  When the MFP 100 determines that the determination has been completed (S208: YES), it determines whether the reading of the one original has been completed (S210). If not completed (S210: NO), the MFP 100 reads continuously until the reading is completed. When the reading is completed (S210: YES), the MFP 100 determines whether or not there is a next original (S212). If there is a next document (S212: YES), the MFP 100 returns to S201 and executes reading and determination of the next document. If there is no next original (S212: NO), the MFP 100 ends the determination reading process.

  It should be noted that reading of the original is completed before the determination is completed, and if there is a next original, MFP 100 may start reading the next original without waiting for completion of the determination. That is, the MFP 100 can execute the determination of the preceding document and the reading of the subsequent document in parallel.

  Returning to FIG. 4, since the determination reading process of S115 is completed, the MFP 100 outputs based on the job instruction (S114) and ends the reading job process. That is, the MFP 100 outputs an image file if it is a scan instruction, prints if it is a copy instruction, and transmits it by FAX if it is a FAX transmission instruction. When printing is performed in response to a copy instruction, the process of S114 is an example of a printing process. When outputting an image file in response to a scan instruction, the process of S114 is an example of an output process.

  As described above in detail, the MFP 100 according to the present embodiment causes the image reading unit 20 to read an image of a document, and sets a determination region that is a determination target region of the document type to be smaller than a region of one document. It is determined whether or not a specific condition that is a condition to be satisfied is satisfied. If it is determined that the specific condition is not satisfied, the determination process is executed using the read area of one original as a determination area. If it is determined that the specific condition is satisfied, the area of one read original is determined. The determination process is executed using the smaller area as the determination area. In the determination process, a process for referring to the image data in the determination area is executed. Therefore, if the determination area is small, the determination can be completed in a short time.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the present invention is not limited to an MFP, and can be applied to any apparatus having an image reading function such as a copying machine, a scanner, and a FAX apparatus. In the above embodiment, the MFP 100 including the image reading unit 20 capable of color reading is used. However, an apparatus only for monochrome reading may be used. A device that only reads black and white does not generate a color image, and therefore does not accept a color reading instruction. In the color determination process, it is determined whether the document is a gray scale document or a monochrome document.

  In addition, as the specific condition, the MFP 100 only needs to have one or more conditions from among the plurality of illustrated limiting conditions and the plurality of changing conditions, and may include only the limiting conditions or only the changing conditions. , You may have both. In the determination process, the MFP 100 may make a determination based on all of the provided conditions, or may make a determination based on some conditions.

  Further, for example, the MFP 100 may not have the procedure for the determination of the change condition and the determination area setting process. In other words, the determination area may be limited only by the determination area initialization process. However, it is preferable to change the determination region according to the condition even during the determination depending on the change condition because the possibility that the determination can be completed earlier is increased.

  In the above-described embodiment, the common determination region is used for the plain color determination and the color determination. In that case, for example, the determination reading process may be executed for each determination process. Then, after both determinations are completed, the reading of the next document may be started.

  Moreover, the procedure of the determination process illustrated in the above embodiment is an example, and the present invention is not limited to this. For example, in the above embodiment, the image data is first divided into blocks and the determination is performed in units of blocks. However, the determination in units of blocks may not be performed. That is, the entire determination area may be determined in units of pixels without being divided into blocks.

  The processing disclosed in the embodiments may be executed by a single CPU, a plurality of CPUs, hardware such as an ASIC, or a combination thereof. Further, the processing disclosed in the embodiment can be realized in various modes such as a recording medium or a method recording a program for executing the processing.

10 Image forming unit 20 Image reading unit 22 ADF
31 CPU
33 RAM
100 MFP

Claims (12)

A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
The determination of the type of the original includes a plain determination for determining whether or not the original is plain;
In the plain color determination, when the ratio of the area determined to be non-solid in the original exceeds a solid threshold, it is determined that the original is not plain.
When it is determined in the determination process that the specific condition is satisfied, the solid threshold value is made smaller than that in the case where the determination process determines that the specific condition is not satisfied. Reader. A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
The determination of the document type includes color determination for determining the color of the document,
In the color determination, when the ratio of the area determined to be color in the original exceeds a color threshold, it is determined that the original is color.
When the determination process determines that the specific condition is satisfied, the color threshold value is made smaller than when the determination process determines that the specific condition is not satisfied. Reader. A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
The determination of the type of the document includes a plain color determination for determining whether or not the document is plain and a color determination for determining the color of the document.
In the determination process, when one of the solid color determination and the color determination is completed, it is determined that the specific condition is satisfied;
Wherein in the determination process, the region up timing is determined that the specific condition is satisfied in the determination processing and the second region, Ru to complete the determination is not completed among said color determination and the solid judgment An image reading apparatus. A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
In the determination process, it is determined that the specific condition is satisfied when the reading unit reads the document in black and white reading,
In the determination process, the image reading apparatus is characterized in that, from the read image read by the reading process, a region obtained by removing a region corresponding to at least a part of at least four edge regions is defined as the second region . A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
In the determination processing, it is determined whether or not the specific condition is satisfied based on a part of the plurality of read images in one job.
In the determination process, when it is determined in the determination process that the specific condition is satisfied, an area including content in the partial read image is determined for the remaining read images of the plurality of read images. An image reading apparatus characterized in that it is a second area . A reading unit for reading an image of a document;
A control unit;
A printing section for printing an image on recording paper;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
A printing process for causing the printing unit to print based on the read image read by the reading process;
The execution,
Furthermore, the control unit
The image reading apparatus according to claim 1, wherein, in the determination process, when the printing unit performs printing in the printing process, the second area is determined based on a margin setting size of the recording paper . A reading unit for reading an image of a document;
A control unit;
With
The controller is
A reading process for causing the reading unit to read an image of a document;
A determination process for determining whether or not a specific condition that is a condition for making a determination area that is a determination target area of a document type smaller than a single document area;
When it is determined that the specific condition is not satisfied in the determination process, the first area which is an area of one original in the read image read in the reading process is set as the determination area, and the type of the original When the determination process determines that the specific condition is satisfied, a second area smaller than the first area in the read image read by the reading process is set as the determination area. Determination processing for determining the type of document,
The execution,
Furthermore, the control unit
The image reading apparatus according to claim 1, wherein the determination process determines that the specific condition is not satisfied when the size of the document is a prescribed size . In the image reading apparatus according to any one of claims 1 to 7 ,
A storage unit,
The controller is
The image reading apparatus according to claim 1, wherein the determination process determines that the specific condition is satisfied when a free space in the storage unit is less than a specified amount. In the image reading device according to any one of claims 1 to 8 ,
The controller is
Executing an output process for outputting an image file based on the read image read by the reading process;
In the determination process, it is determined that the specific condition is satisfied when the format of the image file output in the output process is a specific format storing a plurality of images in one file. An image reading apparatus. In the image reading device according to any one of claims 1 to 9 ,
It has a transport section that transports the document,
The controller is
The image reading apparatus according to claim 1, wherein the determination process determines that the specific condition is satisfied when the distance between the originals of the documents continuously conveyed by the conveyance unit is shorter than a distance threshold. In the image reading device according to any one of claims 1 to 10 ,
The controller is
An image reading apparatus that executes midway change processing for changing the determination area in the middle of determination for one original. In the image reading device according to any one of claims 1 to 9 ,
It has a transport section that transports the document,
The controller is
An image reading apparatus that performs a sheet interval determination process for determining the determination area between documents of documents continuously conveyed by the conveyance unit.

Images