JP6652176B2 - Image reading device and image processing program - Google Patents

Description

  The present invention relates to an image processing device and an image processing program.

  2. Description of the Related Art Conventionally, there has been known an image processing apparatus that executes processing of reading an image of a document and outputting the image to a sheet or a display.

  Some image processing apparatuses of this type are equipped with a blank sheet determination function for determining whether or not a document is a blank document (for example, see Patent Document 1). By installing the blank sheet determination function, for example, it is possible to output an image of a document that is not a blank document and not output an image of a blank document.

JP 2008-219808 A

  However, depending on the content of processing executed by the image processing apparatus, a blank image is output even though it is determined that the document is not a blank document, and the blank page determination result may not match the output result. For example, when a process of converting a document image to a binary image is performed, all pixels of the document may be converted to white pixels, and as a result, a blank image may be output.

  An object of the present invention is to provide an image processing apparatus and an image processing program that can expect an output result that does not contradict a blank page determination result.

  In order to achieve the above object, an image processing apparatus according to one aspect of the present invention includes an acquisition unit that acquires a multivalued image as an acquired image, and a control unit, and the control unit performs a binary process using a threshold. The acquired image is converted into a binary image by a first conversion process that converts the acquired image into a binary image by conversion, and a binary conversion using an error diffusion method or a binary conversion using a threshold different from the first conversion process. Or, a second conversion process of converting the acquired image into a multi-valued image can be executed, based on the acquired image, a multi-valued determination process of determining whether the acquired image is a blank image, A reception process for receiving a setting of whether to enable blank page removal for removing a blank image and a determination process for determining whether an acquired image satisfies a condition for determining a binary image are executed. Setting to disable blank page removal in reception processing If it is determined that the condition is satisfied in the determination process, the first output process of outputting the image after the first conversion process is performed, and the setting for enabling blank sheet removal in the reception process is performed. If it is determined that the acquired image is a blank image in the multi-value determination process, the image is not output, it is determined that the condition is satisfied in the determination process, and the multi-value determination process is performed. If it is determined that the acquired image is not a blank image, a second output process for outputting the image after the conversion by the second conversion process is executed.

  According to this configuration, when the acquisition unit acquires the multi-valued image as the acquired image, the multi-value determination process and the determination process are performed. In the multi-value determination process, it is determined whether the acquired image is a blank image. In the determination processing, it is determined whether or not the acquired image satisfies a condition for determining a binary image.

  It is possible to set valid / invalid of blank paper removal for removing a blank image.

  When blank page removal is set to be invalid, and the acquired image satisfies the condition for determining a binary image, the image converted by the first conversion process is output. The first conversion process is a process of converting an acquired image into a binary image by a binary conversion using a threshold. Since blank page removal is disabled, even if all pixels of the acquired image are converted to white pixels by the first conversion process and the blank image is output, there is no problem in the output result.

  When blank page removal is set to be valid, if the condition for determining the acquired image as a binary image is satisfied and it is determined that the acquired image is a blank image, no image is output. Therefore, the blank page determination result matches the result that no image is output due to blank page removal.

  In addition, in a case where blank page removal is set to be valid, if it is determined that the acquired image satisfies the condition for determining a binary image and that the acquired image is not a blank image, the second conversion process is performed. The converted image is output. The second conversion process is a process of converting an obtained image into a binary image by a binary conversion using an error diffusion method or a binary conversion using a threshold different from that of the first conversion process, or converting the obtained image into a multi-valued image. This is the process of converting to an image. Therefore, in the second conversion process, each pixel of the acquired image can be suppressed from being converted into a white pixel as compared with the first conversion process. As a result, it is possible to suppress output of a blank image even though it is determined that the acquired image is not a blank image.

  Therefore, an output result that does not contradict the blank page determination result can be expected.

  The control unit executes a binary determination process for determining whether or not the image is a blank image based on the image after the conversion by the first conversion process, and the acquired image is not a blank image in the multi-value determination process. When it is determined that the image converted by the first conversion process is not a blank image in the binary determination process, the converted image is output, and the first conversion process is performed by the binary determination process. If it is determined that the image after the conversion is a blank image, the image after the conversion by the second conversion process may be output.

  According to this configuration, the image after the conversion by the first conversion process is determined to be a blank image in the binary determination process, even though the acquired image is determined to be not a blank image in the multi-value determination process. In this case, the image after the conversion by the second conversion process is output. As a result, it is possible to more expect an output result that does not contradict the blank sheet determination result based on the acquired image.

  An image processing apparatus according to another aspect of the present invention includes an acquisition unit that acquires a multivalued image as an acquired image, and a control unit, and the control unit performs a binary conversion process that converts the acquired image into a binary image. A multi-value determination process for determining whether or not the obtained image is a blank image based on the obtained image, and a determination process for determining whether or not the obtained image satisfies a condition for determining a binary image When it is determined that the obtained image is not a blank image in the multi-value determination process, and it is determined that the condition is satisfied in the determination process, whether the binary image obtained by the binary conversion process is a blank image Is performed.

  According to this configuration, when a multivalued image is acquired as an acquired image by the acquiring unit, a binary conversion process is executed. In the binary conversion processing, the acquired image is converted into a binary image. Further, a multi-value determination process and a determination process are performed. In the multi-value determination process, it is determined whether the acquired image is a blank image. In the determination processing, it is determined whether or not the acquired image satisfies a condition for determining a binary image.

  If it is determined in the multi-value determination process that the acquired image is not a blank image, and if it is determined in the determination process that the condition is satisfied, a binary determination process is performed. In the binary determination process, whether or not the binary image is a blank image is determined based on the binary image obtained by the binary conversion process.

  Thereby, for example, when the binary image is determined to be a blank image in the binary determination process, if the binary image is not output, the blank determination result by the binary determination process and the blank paper removal The result that no image is output matches. On the other hand, if it is determined in the multi-value determination process that the acquired image is not a blank image, and if it is determined in the binary determination process that the binary image is not a blank image, the binary image is output. In this case, the blank sheet determination result obtained by the multi-value determination processing and the binary determination processing matches the result that the binary image is output.

  Therefore, an output result that does not contradict the blank page determination result can be expected.

  When the binary image is determined to be a blank image in the binary determination process, the binary image may be deleted.

  Accordingly, when the binary image is determined to be a blank image in the binary determination process, the binary image can be prevented from being output.

  The binary conversion process is a first conversion process of converting an acquired image into a binary image by a binary conversion using a threshold, and the control unit performs a threshold conversion different from the binary conversion by the error diffusion method or the first conversion process. It is possible to execute a second conversion process of converting the obtained image into a binary image by converting the obtained image into a binary image by using a binary conversion process using the binary conversion process in the binary determination process. If it is determined that the binary image obtained by the above is a blank image, a second output process of outputting the image after the conversion by the second conversion process may be executed.

  The second conversion process is a process of converting an obtained image into a binary image by a binary conversion using an error diffusion method or a binary conversion using a threshold different from that of the first conversion process, or converting the obtained image into a multi-valued image. This is the process of converting to an image. Therefore, in the second conversion process, each pixel of the acquired image can be suppressed from being converted into a white pixel as compared with the first conversion process. As a result, it is possible to suppress output of a blank image even though it is determined in the multi-value determination process that the acquired image is not a blank image.

  Therefore, it is possible to expect an output result that does not contradict the blank page determination result by the multi-value determination process.

  The control unit may determine whether or not the obtained image is a blank image based on the luminance component data of the obtained image in the multi-value determination process.

  Further, the image processing device may include a storage unit that stores an image. In this case, the control unit stores the acquired image in the storage unit when the free space of the storage unit is equal to or more than the specified amount, and stores the obtained image in the storage unit when the free space of the storage unit is smaller than the specified amount. Is preferably not stored.

  If there is enough free space in the storage unit, the acquired image is stored in the storage unit. Therefore, when it is necessary to output the image after the conversion by the second conversion process, that is, it is determined that the acquired image is not a blank image in the multi-value determination process, and the first conversion process is performed in the binary determination process. When it is determined that the converted image is a blank image, the acquired image stored in the storage unit can be used for the second conversion process, and the image after the conversion by the second conversion process can be output. it can.

  On the other hand, when there is not enough free space in the storage unit, the acquired image is not stored in the storage unit, so that the storage unit can be suppressed from being pressed by the acquired image. In this case, even if it is determined in the multi-value determination process that the acquired image is not a blank image, it is impossible to output the image after the conversion by the second conversion process. If the converted image is determined to be a blank image, no image is output.

  For the binary conversion in the second conversion process, it is preferable to use a threshold set on a lower density side than the threshold used in the first conversion process.

  Specifically, the threshold value used for the binary conversion in the second conversion process is set such that the obtained image is converted into a binary image including at least a part of the black pixels based on the data of the luminance component of the obtained image. Preferably, it is set.

  By setting the threshold, each pixel of the acquired image is easily converted to a black pixel in the second conversion process. As a result, it becomes difficult to output a blank image.

  The control unit may execute the second conversion process before deciding to output the image after the conversion by the second conversion process.

  According to this configuration, since the second conversion processing is executed in advance, it is possible to expect a higher speed of the second output processing.

  The control unit determines whether the obtained image is chromatic or achromatic based on the color difference data of the obtained image, determines that the obtained image is achromatic, and the obtained image has a luminance component less than the first threshold. Alternatively, the determination target condition in the determination process may be that it is determined that the pixels having the second threshold value or more are included in the predetermined amount or more.

  The control unit executes an output designation process for accepting a designation of outputting a binary image or a multi-valued image, and a determination target condition in the decision process is a designation of outputting a binary image in the output designation process. May have been accepted.

  An image processing program according to still another aspect of the present invention includes a computer that is connected to an image processing apparatus that includes an acquisition unit that acquires a multivalued image as an acquired image, the acquired image being binary-converted using a threshold. The acquired image is converted to a binary image by a first conversion process of converting the acquired image into a binary image or a binary conversion using a threshold different from the first conversion process, or A second conversion process for converting the image into a multi-valued image, and a multi-value determination process for determining whether or not the acquired image is a blank image based on the acquired image, and removing the blank image. A reception process for receiving a setting of whether to enable blank page removal and a determination process for determining whether an acquired image satisfies a condition for determining a binary image are executed. If it is determined that the condition is satisfied in the determination process when the setting for invalidating the deletion is received, a first output process of outputting an image converted by the first conversion process is executed, and a blank page is received in the reception process. In a case where the setting for enabling the removal is received, if it is determined in the multi-value determination process that the acquired image is a blank image, the image is not output, and it is determined that the condition is satisfied in the determination process, and If it is determined in the multi-value determination process that the acquired image is not a blank image, a second output process of outputting the image after the conversion by the second conversion process is executed.

  In the computer in which the image processing program is installed, multi-value determination processing and determination processing are executed. In the multi-value determination process, it is determined whether the acquired image is a blank image. In the determination processing, it is determined whether or not the acquired image satisfies a condition for determining a binary image.

  In addition, it is possible to set valid / invalid of blank sheet removal for removing a blank image.

  When blank page removal is set to be invalid, and the acquired image satisfies the condition for determining a binary image, the image converted by the first conversion process is output. The first conversion process is a process of converting an acquired image into a binary image by a binary conversion using a threshold. Since blank page removal is disabled, even if all pixels of the acquired image are converted to white pixels by the first conversion process and the blank image is output, there is no problem in the output result.

  When blank page removal is set to be valid, if the condition for determining the acquired image as a binary image is satisfied and it is determined that the acquired image is a blank image, no image is output. Therefore, the blank page determination result matches the result that no image is output due to blank page removal.

  In addition, in a case where blank page removal is set to be valid, if it is determined that the acquired image satisfies the condition for determining a binary image and that the acquired image is not a blank image, the second conversion process is performed. The converted image is output. The second conversion process is a process of converting an obtained image into a binary image by a binary conversion using an error diffusion method or a binary conversion using a threshold different from that of the first conversion process, or converting the obtained image into a multi-valued image. This is the process of converting to an image. Therefore, in the second conversion process, each pixel of the acquired image can be suppressed from being converted into a white pixel as compared with the first conversion process. As a result, it is possible to suppress output of a blank image even though it is determined that the acquired image is not a blank image.

  Therefore, an output result that does not contradict the blank page determination result can be expected.

  An image processing program according to still another aspect of the present invention provides a computer which is connected to an image processing apparatus having an acquisition unit that acquires a multi-valued image as an acquired image, the binary conversion processing of converting the acquired image into a binary image. A multi-value determination process for determining whether or not the obtained image is a blank image based on the obtained image, and a determination for determining whether or not the obtained image satisfies a condition for determining a binary image Processing, when it is determined that the acquired image is not a blank image in the multi-value determination process, and when it is determined in the determination process that the condition is satisfied, whether the binary image obtained by the binary conversion process is a blank image And a binary determination process for determining whether

  In the computer in which the image processing program is installed, a binary conversion process, a multi-value determination process, and a determination process are executed. In the binary conversion process, a multi-valued image acquired as an acquired image by the acquisition unit is converted into a binary image. In the multi-value determination process, it is determined whether the acquired image is a blank image. In the determination processing, it is determined whether or not the acquired image satisfies a condition for determining a binary image.

  If it is determined in the multi-value determination process that the acquired image is not a blank image, and if it is determined in the determination process that the condition is satisfied, a binary determination process is performed. In the binary determination process, whether or not the binary image is a blank image is determined based on the binary image obtained by the binary conversion process.

  Thereby, for example, when the binary image is determined to be a blank image in the binary determination process, if the binary image is not output, the blank determination result by the binary determination process and the blank paper removal The result that no image is output matches. On the other hand, if it is determined in the multi-value determination process that the acquired image is not a blank image, and if it is determined in the binary determination process that the binary image is not a blank image, the binary image is output. In this case, the blank sheet determination result obtained by the multi-value determination processing and the binary determination processing matches the result that the binary image is output.

Therefore, an output result that does not contradict the blank page determination result can be expected.
Further, an image reading device according to one aspect of the present invention includes an image reading unit, a control unit, and an operation unit, and the control unit is configured to generate a multi-valued image generated by reading a document by the image reading unit Image acquisition processing for acquiring image data, and setting acquisition processing for acquiring setting information set via the operation unit, wherein the setting information includes first setting information for outputting as a multi-valued image. The setting acquisition process, including second setting information for automatically determining whether to output as a multi-valued image or a binary image, and a multi-valued image represented by the multi-valued image data acquired by the image acquisition process. Executing a first blank page determination process for determining whether the value image represents a blank page image. Further, when the control unit determines that the first blank page determination process represents a blank page image, the multi-valued image First deletion processing to delete data and before A first output process of outputting the multi-valued image when it is determined that the blank image is not represented by the first blank page determination process, and the setting information acquired by the setting acquisition process is the first setting information; If the first blank sheet determination process determines that a blank image is not represented, and the setting information acquired by the setting acquisition process is the second setting information, the multi-valued image data acquired by the image acquisition process is A determination process of determining whether a multi-valued image to be represented satisfies a condition for outputting as a binary image; A second blank sheet determination process for determining whether or not the binary image represented by the data represents a blank image; and determining that the binary image is a blank image in the second blank page determination process. A second deletion process for deleting, a second output process for outputting the binary image when it is determined in the second blank page determination process that the binary image is not a blank image, and a condition that the condition is not satisfied in the determination process. If it is determined, a third output process of outputting a multi-valued image represented by the multi-valued image data is executed.
The image processing program according to one aspect of the present invention includes an acquisition process of acquiring the setting information corresponding to the multi-level image data and the multi-valued image data generated by the image reading apparatus, the pre-Symbol multivalued image data And causing the computer to execute a multi-value determination process for determining whether or not the constituent multi-value image represents a blank image . Further, the multi-value image determined to represent the blank image by the multi-value determination process is deleted. A first deletion process and a first setting for determining that the multi-value image does not represent a blank image by the multi-value determination process, and for outputting the setting information acquired by the acquisition process as a multi-value image. If the information, the first output processing for outputting the multi-value image, the previous SL the multivalued image by the multivalued determination process determines that do not represent a blank image, and acquired by the acquisition process Lots of setting information When the second setting information is for automatically determining whether to output as an image or a binary image, a condition for outputting a multi-valued image constituting the multi-valued image data as a binary image is set. A binary image represented by converted binary image data obtained by binarizing the multi-valued image data when the determination process determines whether the condition is satisfied, and when the determination process determines that the condition is satisfied, A second determination process for determining whether or not the binary image is deleted, and a second deletion process for deleting an image in which the binary image is determined to be a blank image by the binary determination process;
A second output process for outputting an output image based on the binary image data, wherein the binary image is an image determined to be not a blank image by the binary determination process, and if the condition is not satisfied by the determination process, And a third output process of outputting an output image based on the multi-valued image data when the determination is made.

  According to the present invention, an output result that does not contradict the blank page determination result can be expected.

1 is a block diagram illustrating a configuration of an MFP (Multi-Function Peripheral) according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a control unit. It is a flowchart which shows the flow of a reading process. It is a flowchart which shows the content of a block setting process. It is a flowchart which shows the content of an initialization process. It is a flowchart which shows the content of an automatic setting process. 9 is a flowchart illustrating the content of a color setting process. It is a flowchart which shows the content of a thing setting process. 9 is a flowchart illustrating a flow of an image output process. 9 is a flowchart illustrating a flow of a blank sheet non-removal process. 9 is a flowchart illustrating a flow of a binary image output process. It is a flowchart which shows the flow of a 2nd conversion process. It is a flowchart which shows the flow of a binary determination process. 13 is a flowchart illustrating another example of the second conversion process. 15 is a flowchart illustrating still another example of the second conversion process. 13 is a flowchart illustrating another example of the binary determination process. 9 is a flowchart illustrating another example of the image output process.

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

<Hardware configuration>

  As shown in FIG. 1, an MFP (Multi-Function Peripheral) 1 as an example of an image processing apparatus includes an image forming unit 10, an image reading unit 20, an operation panel 30, a network interface (I / F) 40, and a control unit. 50.

  The image forming unit 10 performs printing (color printing or monochrome printing) based on image data, and forms an image on a print sheet or the like. The image forming method may be an electrophotographic method or an ink jet method.

  The image reading unit 20 as an example of an obtaining unit reads an image of a document and generates image data. The reading method may be an ADF (Auto Document Feeder) method for reading the image of the document while conveying the document, or an FB (Flat Bed) for reading the image of the document by placing the document on the contact glass. ) Method.

  The operation panel 30 includes a touch panel. Various information is displayed on the touch panel. In addition, various inputs can be performed by a touch operation of the touch panel. The operation panel 30 may be provided with input keys such as numeric keys.

  By providing the network interface 40, the MFP 1 can communicate with an external device such as a PC (personal computer) connected to a LAN (Local Area Network) via the LAN.

  The control unit 50 includes a CPU 51, a ROM 52, a RAM 53, an NVRAM (Non Volatile RAM) 54, and an ASIC 55. The CPU 51 controls the image forming unit 10, the image reading unit 20, and the operation panel 30 by executing programs for various processes, and controls data communication via the network interface 40. The ROM 52 stores programs executed by the CPU 51 and various data. The RAM 53 as an example of a storage unit is used as a work area when the CPU 51 executes a program. The NVRAM 54 stores various setting values input from the operation panel 30 and the like.

<Functions and settings>

  The MFP 1 reads an image of a document by the image reading unit 20, outputs the read image (image data) to a print sheet or the like by the image forming unit 10, or outputs the read image to an external PC or the like via the network interface 40. Reading function.

  When using this reading function, the user can operate the operation panel 30 to set the scan type. As the scan type, four types of BW (black and white), gray, color and auto are prepared. When “scan type: BW” is set, the image of the document is read as a black and white binary image (BW image), and a BW binary image is output. When “scan type: gray” is set, the image of the original is read as a gray image which is a black and white image having an intermediate gradation, and a gray Jpeg image of 256 gradations is output. When “scan type: color” is set, the image of the document is read as a color image, and a color Jpeg image of 256 gradations is output. When “scan type: auto” is set, it is automatically determined whether the image type of the document is a BW image, a gray image, or a color image, and an image according to the determination result is output.

  Note that the number of gradations of the gray Jpeg image and the color Jpeg image is an example, and may be a number of gradations smaller than 256 gradations or a number of gradations larger than 256 gradations. Further, the gray Jpeg image and the color Jpeg image are files in the Jpeg format, but the file format of the output image may be a file format other than the Jpeg format, such as a TIFF format, an XPS format, or a PDF format.

  The MFP 1 has a blank paper removing function. The blank page removing function is a function of determining whether or not the image of the document read by the image reading unit 20 is a blank page image, and not outputting a blank page image if the blank page image is found. The user can operate the operation panel 30 to set whether to enable or disable the blank sheet removing function.

<Configuration of control unit>

  By executing the program, the CPU 51 of the control unit 50 executes the CIS control unit 511, the reading correction unit 512, the image processing unit 513, the blank page determination unit 514, the color number detection unit 515, the JPEG compression unit 516, and the like illustrated in FIG. The function of the binary conversion unit 517 is realized.

  The CIS control unit 511 controls a CIS (Contact Image Sensor) 201 and an AFE (Analog Front End) 202 provided in the image reading unit 20. As a control mode of the CIS control unit 511, a color mode suitable for reading a color image and a mono mode suitable for reading a BW image and a gray image are provided. When the CIS control unit 511 controls the CIS 201 and the AFE 202, the CIS 201 outputs an analog image signal corresponding to the reflected light from the original. Is converted to

  The reading correction unit 512 performs reading correction on the image (8-bit digital image data) output from the AFE 202 to eliminate unevenness in the amount of light applied to the document (illumination unevenness) and uneven pixel density due to other causes. (Shading correction). As a correction mode of the reading correction unit 512, a color mode for performing reading correction suitable for a color image and a mono mode for performing reading correction suitable for a BW image and a gray image are provided. The reading correction unit 512 stores the image after the reading correction in the RAM 53.

  The image processing unit 513 performs various types of image processing on the read and corrected image. As a processing mode of the image processing unit 513, a color mode for performing image processing suitable for a color image and a mono mode for performing image processing suitable for a BW image and a gray image are provided. The image processing includes, for example, edge enhancement processing for enhancing the edges of the image, resolution changing processing for changing the resolution of the image, and color conversion processing for converting the color space of the image from RGB to YCbCr. The image processing unit 513 stores the image after the image processing in the RAM 53.

  Further, the image processing unit 513 divides the image after the color conversion processing into a plurality of blocks in a grid pattern with 100 × 100 pixels as one block, and for each block, a histogram of a Y component (luminance component), Cb A histogram of the component (color difference data) and a histogram of the Cr component (color difference data) are created. Then, the image processing unit 513 stores the histogram of the Y component, the histogram of the Cb component, and the histogram of the Cr component created for each block in the RAM 53.

  The blank page determination unit 514 determines whether the image after the color conversion processing by the image processing unit 513 is a blank page image.

  Specifically, the blank page determination unit 514 refers to the histogram of the Y component for each block stored in the RAM 53, and obtains the mode value of the Y component for each block. In a block of almost white color, the mode value of the Y component is concentrated near 255. When the entire image is almost white, if a histogram of the mode of the Y component for each block is created, the mode in the histogram is concentrated near 255. Therefore, the blank page determination unit 514 obtains the number of blocks having the mode of the Y component that matches the “mode in the histogram of the mode of the Y component for each block”, and the number of blocks is equal to or greater than a certain value. If, the image after the color conversion processing is determined to be a blank image. Then, the blank sheet determination unit 514 stores the determination result in the RAM 53. Hereinafter, the determination by the blank sheet determination unit 514 is referred to as “multi-value determination”.

  When the blank page removing function is set to be invalid, the blank page determining unit 514 is set to be invalid, and the multi-value determination is not performed.

  The color number detection unit 515 detects the number of colors and determines whether the type of the image after the color conversion processing by the image processing unit 513 is a BW image, a gray image, or a color image.

  Specifically, the color number detection unit 515 determines whether each block stored in the RAM 53 is a chromatic block or an achromatic block. In the YCbCr color space, when the range of the value of the Cb component and the value of the Cr component are set to 0 to 255, respectively, the pixel in which the value of the Cb component and the value of the Cr component are each near a substantially intermediate value (= 127) Color becomes almost achromatic. Therefore, the number-of-colors detection unit 515 refers to the histogram of the Cb component and the histogram of the Cr component for each block, and, for example, if both of the following equations (1) and (2) are satisfied, the achromatic block is used. If it is determined that there is, and if at least one of the following equations (1) and (2) is not satisfied, it is determined that the block is a chromatic color block.

  112 ≦ Cb average value <143 (1)

  112 ≦ Average value of Cr component <143 (2)

  The numerical values in the expressions (1) and (2) are merely examples, and may be changed as appropriate. The same applies to the following equation (3).

  Thereafter, the color number detection unit 515 determines whether each achromatic block is a BW block or a gray block. In the YCbCr color space, when the range of the Y component value, the Cb component value, and the Cr component value is 0 to 255, respectively, the Cb component value and the Cr component value are almost intermediate values (= 127). When the value of the Y component is closer to 0, the color of the pixel is closer to black, and as the value of the Y component is closer to 255, the color of the pixel is closer to white. Therefore, the number-of-colors detection unit 515 refers to the histogram of the Y component for each achromatic block and, for example, if the following equation (3) is satisfied, determines that the block is a BW block, and determines the following equation (3). If is not satisfied, it is determined that the block is a gray block.

“Ratio of pixels satisfying Y component value <63 or 224 ≦ Y component value” ≧ 40%
... (3)

  Then, the number-of-colors detection unit 515 determines whether each mode value of the Cb component and the Cr component in the image after image processing (image of one page) is both in the range of 112 or more and less than 143, or If the image contains color blocks of a certain ratio (for example, 0.2%) or more, it is determined that the type of the image after the image processing is a color image. At least one of the modal values of the Cb component and the Cr component in the image after the image processing is out of the range of 112 or more and less than 143, and the ratio of the gray blocks in the image after the image processing is constant (for example, 0. 3%) or more, it is determined that the type of the image after the image processing is a gray image. Further, at least one of each mode of the Cb component and the Cr component in the image after the image processing is out of the range of 112 or more and less than 143, and the ratio of the gray blocks in the image after the image processing is less than a certain value. In this case, it is determined that the type of the image after the image processing is a BW image.

  When “scan type: auto” is set, the number-of-colors detection unit 515 is enabled, and “scan type: BW”, “scan type: gray”, and “scan type: color” are set. If there is, the color number detection unit 515 is set to be invalid. When the number-of-colors detection unit 515 is set to be invalid, the above-described determination by the number-of-colors detection unit 515 is not performed.

  The Jpeg compression unit 516 compresses the image-processed image stored in the RAM 53 by the Jpeg method to generate a gray Jpeg multivalued image or a color Jpeg multivalued image.

  Specifically, the operation modes of the Jpeg compression unit 516 include a mode for generating only a gray Jpeg multivalued image and a mode for generating only a color Jpeg multivalued image, and each operation mode is selectively enabled. Set or all operation modes are set to disabled. When “scan type: BW” is set, all the operation modes of the Jpeg compression unit 516 are set to be invalid, and the Jpeg compression unit 516 does not generate any of the gray Jpeg multivalued image and the color Jpeg multivalued image. . When “scan type: gray” is set, a mode for generating only a gray Jpeg multi-valued image is set to be valid (gray), and the Jpeg compression unit 516 generates only a gray Jpeg multi-valued image. When “scan type: color” is set, the mode for generating only a color Jpeg multivalued image is set to valid (color), and the Jpeg compression unit 516 generates only a color Jpeg multivalued image. When “scan type: auto” is set, a mode for generating a gray Jpeg multi-valued image or a color Jpeg multi-valued image is set to valid (color / gray), and the Jpeg compression unit 516 detects the number of colors. According to the determination result of the unit 515, either a gray Jpeg multivalued image or a color Jpeg multivalued image is generated. Then, the Jpeg compression unit 516 stores the generated gray Jpeg multi-valued image or color Jpeg multi-valued image in the RAM 53.

  When “scan type: BW” or “scan type: auto” is set, the binary conversion unit 517 performs a binary conversion on the image after the image processing, which is enabled and stored in the RAM 53, Generate a BW binary image. When the binary conversion unit 517 is set to be valid, a simple binary mode and an error diffusion mode are selectively set as the binary conversion mode. Normally, the simple binarization mode is set, and the binary conversion unit 517 converts the pixel into a white pixel if the value of the Y component is equal to or greater than a certain threshold for each pixel of the image after the image processing. , Y component is less than the threshold, the pixel is converted to a black pixel. The binary conversion unit 517 stores the generated BW binary image in the RAM 53. When “scan type: gray” or “scan type: color” is set, the binary conversion unit 517 is invalidated, and the binary conversion unit 517 does not generate a BW binary image.

  Further, the binary conversion unit 517 executes a binary determination process described later, and determines whether the BW binary image is a blank image. Hereinafter, the determination by the binary conversion unit 517 is referred to as “binary determination”.

<Read processing>

  When the user operates the operation panel 30 and inputs an instruction to read an image of a document, the CPU 51 of the control unit 50 executes the reading process shown in FIG. 3 for each page of the document.

  In the reading process, the CPU 51 executes a block setting process (S1). The block setting process will be described later.

  After the end of the block setting process, the CPU 51 starts the reading operation of the document by the image reading unit 20 (S2). With the start of this reading operation, the processing by the CIS control unit 511 shown in FIG. 2 is started.

  Thereafter, the CPU 51 determines whether reading of one page of the document has been completed (S3). When the image of the document is read by the ADF method, for example, it is determined that the reading of one page of the document has been completed because the document of one page (one sheet) has passed over the CIS 201 of the image reading unit 20. Can be. When the image of the document is read by the FB method, it can be determined that reading of one page of the document has been completed, for example, when the CIS 201 makes one reciprocation in the sub-scanning direction.

  If the reading of one page of the document has not been completed (S3: NO), the process returns to S3 again, and if the reading of one page of the document has been completed (S3: YES), the processing by the reading correction unit 512 and the image processing unit 513 is terminated. Be started. Further, the CPU 51 determines whether or not the blank sheet removing function is set to be valid (S4).

  When the blank page removal function is set to be valid (S4: YES), the multi-value determination by the blank page determination unit 514 is performed. Then, the CPU 51 determines whether or not the result of the multi-value determination by the blank page determination unit 514 is a “blank image” (S5).

  If the result of the multi-value determination is “blank image” (S5: YES), if the gray Jpeg multi-value image or the color Jpeg multi-value image is stored in the RAM 53, the CPU 51 deletes them from the RAM 53, The reading process ends. If the BW binary image is stored in the RAM 53, the CPU 51 deletes the BW binary image from the RAM 53 (S6) and ends the reading process.

  When the scan type is set to auto and the processing by the image processing unit 513 ends, the color number detection by the color number detection unit 515 is performed. After that, depending on the determination result of the number of colors detection, a color Jpeg multi-valued image is generated by the Jpeg compression unit 516, a gray Jpeg multi-valued image is generated by the Jpeg compression unit 516, or the Jpeg compression unit 516 is generated. Generates a gray Jpeg multi-valued image, generates a BW binary image by the binary conversion unit 517, and stores the generated image in the RAM 53. When the scan type is set to color, after processing by the image processing unit 513, a color Jpeg multivalued image is generated by the Jpeg compression unit 516, and the color Jpeg multivalued image is stored in the RAM 53. When the scan type is set to gray, after processing by the image processing unit 513, a gray Jpeg multivalued image is generated by the Jpeg compression unit 516, and the gray Jpeg multivalued image is stored in the RAM 53. When the scan type is set to BW, a binary conversion unit 517 generates a BW binary image after processing by the image processing unit 513, and the BW binary image is stored in the RAM 53.

  When the result of the multi-value determination is not “blank image” (S5: NO), the CPU 51 executes an image output process (S7) and ends the reading process. The image output processing will be described later.

  On the other hand, when the blank page removing function is set to be invalid (S4: NO), the CPU 51 executes a blank page non-removing process (S8), and ends the reading process.

<Block setting processing>

  FIG. 4 shows the flow of the block setting process executed in step S1 shown in FIG.

  In the block setting process, the CPU 51 executes an initial setting process (S11). The initial setting process will be described later.

  After the completion of the initial setting process, the CPU 51 determines whether or not “scan type: auto” is set (S12).

  When “scan type: auto” is set (S12: YES), the CPU 51 executes an auto setting process (S13). The automatic setting process will be described later.

  If “scan type: auto” is not set (S12: NO), the CPU 51 determines whether “scan type: color” is set (S14).

  If “scan type: color” is set (S14: YES), the CPU 51 executes a color setting process (S15). The color setting process will be described later.

  When neither “scan type: auto” nor “scan type: color” is set (S14: NO), the CPU 51 executes a mono setting process (S16). The item setting process will be described later.

  After the completion of the automatic setting process, the color setting process, or the mono setting process, the CPU 51 determines whether the blank sheet removing function is set to be valid (S17).

  If the blank page removal function is set to be valid (S17: YES), the CPU 51 sets the blank page determination unit 514 to valid (S18), and ends the block setting process.

  If the blank page removal function is set to be invalid (S17: NO), the process of step S18 is skipped, and the block setting process ends without setting the blank page determination unit 514 to valid.

<Initial setting process>

  FIG. 5 shows the contents of the initialization processing executed in step S11 shown in FIG.

  In the initial setting process, the CPU 51 invalidates all of the JPEG compression unit 516, the binary conversion unit 517, the blank page determination unit 514, and the color number detection unit 515 (S111, S112, S113, S114), and ends the initial setting process. I do.

<Auto setting process>

  FIG. 6 shows the contents of the automatic setting process executed in step S13 shown in FIG.

  In the automatic setting process, the CPU 51 performs the following various settings.

  The control mode of the CIS control unit 511 is set to a color mode suitable for reading a color image (S131).

  The correction mode of the reading correction unit 512 is set to a color mode for performing reading correction suitable for a color image (S132).

  The processing mode of the image processing unit 513 is set to a color mode for performing image processing suitable for a color image (S133).

  As an operation mode of the Jpeg compression unit 516, a mode for generating either a gray Jpeg multivalued image or a color Jpeg multivalued image is set to valid (color / gray) (S134).

  The binary conversion unit 517 is set to an effective and simple binary mode (S135).

  The number-of-colors detection unit 515 is set to be valid (S136).

<Color setting process>

  The content of the color setting process executed in step S15 shown in FIG. 4 is shown in FIG.

  In the color setting process, the CPU 51 performs the following various settings.

  The control mode of the CIS control unit 511 is set to a color mode suitable for reading a color image (S151).

  The correction mode of the reading correction unit 512 is set to a color mode for performing reading correction suitable for a color image (S152).

  The processing mode of the image processing unit 513 is set to a color mode for performing image processing suitable for a color image (S153).

  As an operation mode of the JPEG compression unit 516, a mode for generating only a color JPEG multi-valued image is set to be valid (color) (S154).

<Product setting process>

  FIG. 8 shows the contents of the item setting process executed in step S16 shown in FIG.

  In the mono setting process, the CPU 51 sets the control mode of the CIS control unit 511 to a mono mode suitable for reading a BW image and a gray image (S161).

  Also, the correction mode of the reading correction unit 512 is set to the mono mode for performing reading correction suitable for the BW image and the gray image (S162).

  Further, the processing mode of the image processing unit 513 is set to a mono mode for performing image processing suitable for a BW image and a gray image (S163).

  Thereafter, the CPU 51 determines whether “scan type: gray” is set (S164).

  If “scan type: gray” is not set (S164: NO), the CPU 51 sets the binary conversion unit 517 to an effective and simple binary mode (S165).

  Then, the CPU 51 determines whether or not there is a sufficient free space in the RAM 53, specifically, whether or not the free space in the RAM 53 is equal to or more than a specified amount (for example, 30 MB) (S166).

  If the free space is equal to or more than the specified amount, the CPU 51 determines that there is sufficient free space in the RAM 53 (S166: YES), and the image processing stored in the RAM 53 even after the binary conversion unit 517 generates the image. A setting is made to continue saving without erasing the subsequent image (S167), and the mono setting process ends.

  If the free space is less than the specified amount, the CPU 51 determines that there is not enough free space in the RAM 53 (S166: NO), skips the process of step S167, and ends the mono setting process. In this case, after the image is generated by the binary conversion unit 517, the image after the image processing stored in the RAM 53 is deleted.

  If “scan type: gray” is set (S164: YES), the CPU 51 sets, as the operation mode of the Jpeg compression unit 516, the mode for generating only the gray Jpeg multi-valued image to be valid (gray). (S168), the item setting process ends.

<Image output processing (1)>

  FIG. 9 shows the flow of the image output process executed in step S7 shown in FIG.

  In the image output process, the CPU 51 determines whether “scan type: auto” is set (S701).

  When “scan type: auto” is set, a mode for generating a gray Jpeg multi-valued image or a color Jpeg multi-valued image is effective as the operation mode of the Jpeg compression unit 516 in the above-described auto setting process (color / Gray) and the binary conversion unit 517 is enabled.

  If “scan type: auto” is set (S701: YES), the CPU 51 determines whether or not the result of the determination by the color number detection unit 515 is “BW image” (S702).

  When the result of the determination by the color number detection unit 515 is “BW image” (S702: YES), the generation of the BW binary image and the binary determination by the function of the binary conversion unit 517 are executed. Further, as described above, a gray Jpeg multi-valued image is generated by the function of the Jpeg compression unit 516. Then, the CPU 51 determines whether or not the result of the binary determination by the binary conversion unit 517 is a “blank image” (S703).

  If the result of the binary determination is a “blank image” (S703: YES), the CPU 51 generates a gray Jpeg multivalued image using the function of the Jpeg compression unit 516, and the gray Jpeg multivalued image is designated in advance. The data is output to the output destination (for example, the image forming unit 10 or a PC connected to the LAN) (S704). With this, when the result of the binary determination is “blank image” even though the result of the multi-value determination is not “blank image”, the gray Jpeg multi-value image can be output instead of the blank image. it can.

  After outputting the gray Jpeg multi-value image, the CPU 51 ends the image output process.

  If the result of the binary determination is not “blank image” (S703: NO), the CPU 51 outputs the BW binary image created by the function of the binary conversion unit 517 to an output destination specified in advance ( S705), the image output processing ends.

  On the other hand, when the result of the determination by the color number detection unit 515 is not “BW image” (S702: NO), the CPU 51 determines whether the result of the determination by the color number detection unit 515 is “color image”. Judge (step S706)

  If the result of the determination by the color number detection unit 515 is “color image” (S706: YES), the CPU 51 generates a color Jpeg multi-valued image by the function of the Jpeg compression unit 516, and The value image is output to an output destination specified in advance (S707). Then, the CPU 51 ends the image output processing.

  If the result of the determination by the number-of-colors detection unit 515 is not “BW image” or “color image” (S706: NO), the CPU 51 uses the function of the Jpeg compression unit 516 to convert the gray Jpeg multivalued image. Then, the generated gray Jpeg multivalued image is output to an output destination designated in advance (S704). Then, the CPU 51 ends the image output processing.

  If “scan type: auto” is not set (S701: NO), the CPU 51 determines whether “scan type: BW” is set (S708).

  When “scan type: BW” is set, the binary conversion unit 517 is set to be valid in the above-described mono setting process.

  When “scan type: BW” is set (S708: YES), binary conversion and binary determination are performed by the function of the binary conversion unit 517. Then, the CPU 51 determines whether or not the result of the binary determination by the binary conversion unit 517 is “blank image” (S709).

  If the result of the binary determination is “blank image” (S709: YES), the CPU 51 executes a binary image output process (S710) and ends the image output process.

  If the result of the binary determination is not “blank image” (S709: NO), the CPU 51 outputs the BW binary image created by the function of the binary conversion unit 517 to an output destination designated in advance ( S711), the image output process ends.

  If “scan type: BW” is not set (S708: NO), the CPU 51 determines whether “scan type: gray” is set (S712).

  When “scan type: gray” is set, the mode for generating only the gray Jpeg multi-valued image is set to valid (gray) as the operation mode of the Jpeg compression unit 516 in the above-described mono setting process. I have.

  If “scan type: gray” is set (S712: YES), the CPU 51 outputs the gray Jpeg multivalued image created by the function of the Jpeg compression unit 516 to an output destination specified in advance (S713). Then, the image output process ends.

  If none of “scan type: auto”, “scan type: BW” and “scan type: gray” are set, that is, if “scan type: color” is set (S712: NO), In the above-described color setting process, a mode for generating only a color Jpeg multi-value image is set to valid (color) as an operation mode of the Jpeg compression unit 516. In this case, the CPU 51 outputs the color Jpeg multivalued image created by the function of the Jpeg compression unit 516 to an output destination specified in advance (S714), and ends the image output processing.

<Blank sheet non-removal processing>

  FIG. 10 shows the flow of the blank sheet non-removal process executed in step S8 shown in FIG.

  In the blank sheet non-removal process, the CPU 51 determines whether “scan type: auto” is set (S801).

  When “scan type: auto” is set, a mode for generating a gray Jpeg multi-valued image or a color Jpeg multi-valued image is effective as the operation mode of the Jpeg compression unit 516 in the above-described auto setting process (color / Gray) and the binary conversion unit 517 is enabled.

  If “scan type: auto” is set (S801: YES), the CPU 51 determines whether or not the result of the determination by the color number detection unit 515 is “BW image” (S802).

  If the result of the determination by the color number detection unit 515 is not “BW image” (S802: NO), the CPU 51 determines whether the result of the determination by the color number detection unit 515 is “color image”. (Step S803)

  If the result of the determination by the color number detection unit 515 is “color image” (S803: YES), the CPU 51 generates a color Jpeg multivalued image by the function of the Jpeg compression unit 516, and The value image is output to an output destination specified in advance (S804). Then, the CPU 51 ends the blank sheet non-removal processing.

  If the result of the determination by the color number detection unit 515 is not “BW image” or “color image” (S803: NO), the CPU 51 uses the function of the Jpeg compression unit 516 to convert the gray Jpeg multivalued image. The multi-valued gray Jpeg image is generated and output to an output destination specified in advance (S805). Then, the CPU 51 ends the blank sheet non-removal processing.

  If the result of the determination by the color number detection unit 515 is “BW image” (S802: YES), the CPU 51 outputs the BW binary image generated by the function of the binary conversion unit 517 to the output destination specified in advance. (S806), and the blank sheet non-removal process ends.

  On the other hand, when “scan type: auto” is not set (S801: NO), the CPU 51 determines whether “scan type: color” is set (S807).

  If “scan type: color” is not set (S807: NO), the CPU 51 determines whether “scan type: BW” is set (S808).

  When “scan type: BW” is set, the binary conversion unit 517 is set to be valid in the above-described mono setting process.

  If “scan type: BW” has been set (S808: YES), the CPU 51 outputs the BW binary image created by the function of the binary conversion unit 517 to an output destination specified in advance (S809), and outputs a blank page. The non-removal processing ends.

  If none of “scan type: auto”, “scan type: color” and “scan type: BW” are set, that is, if “scan type: gray” is set (S808: NO), In the above-mentioned mono setting process, a mode for generating only a gray Jpeg multi-valued image is set to valid (gray) as the operation mode of the Jpeg compression unit 516. In this case, the CPU 51 outputs the gray Jpeg multi-valued image created by the function of the Jpeg compression unit 516 to an output destination designated in advance (S810), and ends the blank non-removal processing.

  If “scan type: color” is set (S807: YES), in the above-described color setting process, the mode for generating only the color Jpeg multi-valued image is enabled (color) as the operation mode of the Jpeg compression unit 516. Is set. In this case, the CPU 51 outputs the color JPEG multi-valued image created by the function of the JPEG compression unit 516 to the output destination designated in advance (S811), and ends the blank non-removal processing.

<Binary image output processing>

  FIG. 11 shows the flow of the binary image output process executed in step S710 shown in FIG.

  In the binary image output process, the CPU 51 determines whether or not the image after the image processing is stored in the RAM 53 (S31).

  If the image after the image processing is stored in the RAM 53 (S31: YES), the CPU 51 executes the second conversion processing (S32), and ends the binary image output processing. The second conversion processing will be described later.

  When the image after the image processing is not stored in the RAM 53 (S31: NO), the CPU 51 deletes the BW binary image stored in the RAM 53 because the second conversion process cannot be executed (S33). The binary image output processing ends without outputting the image.

<Second conversion process (1)>

  FIG. 12 shows an example of the second conversion processing executed in step S32 shown in FIG.

  In the second conversion process, the CPU 51 switches the binary conversion mode of the binary conversion unit 517 from the simple binary mode to the error diffusion mode (S321).

  Then, the CPU 51 performs a binary conversion on the image after the image processing stored in the RAM 53 by the function of the binary conversion unit 517 to regenerate a BW binary image (S322).

  After that, the CPU 51 outputs the regenerated BW binary image to an output destination designated in advance (S323), and ends the second conversion process.

  Note that the second conversion process illustrated in FIG. 12 may be executed in advance before it is determined that the second conversion process is to be executed.

<Binary judgment processing (1)>

  FIG. 13 shows the flow of the binary determination process by the binary conversion unit 517.

  In the binary determination process, the CPU 51 determines whether or not the number of dots (number of pixels) of black pixels in the BW binary image is equal to or greater than a predetermined threshold value, for example, 10 dots (S101).

  If the number of dots of the black pixel is 10 or more (S101: YES), the CPU 51 determines that the BW binary image is not a blank image, saves the determination result in the RAM 53 (S102), and performs the binary determination. The process ends.

  When the number of dots of the black pixels is less than 10 (S101: NO), the CPU 51 determines that the BW binary image is a blank image, stores the determination result in the RAM 53 (S103), and performs the binary determination. The process ends.

  As described above, by counting the number of dots of black pixels in the BW binary image and comparing the counted number of dots with a threshold value, it is easy to determine whether the BW binary image is a blank image. Can be. In addition, since the method of the binary determination is simple, it is possible to expect a higher speed of the binary determination processing.

<Effects>

  As described above, after the multi-level image is acquired by the image reading unit 20 and the image processing is performed, when the image after the image processing is generated, the multi-value determination by the blank page determination unit 514 is performed. Then, the setting of the scan type is determined, and when “scan type: auto” is set, the color number detection by the color number detection unit 515 is performed.

  When the blank sheet removal function is disabled and “scan type: BW” is set, or when the result of the determination by the color number detection unit 515 is “BW image”, the function of the binary conversion unit 517 is performed. The BW binary image generated by the binary conversion in the simple binary mode according to the above is output. Since the blank page removal function is disabled, even if all pixels of the image after image processing are converted to white pixels by binary conversion in the simple binary mode and the blank image is output, there is a problem with the output result. There is no.

  If the blank page removal function is set to be valid and the result of the multi-value determination by the blank page determination unit 514 is a “blank image”, no image is output. Therefore, the result of the multi-value determination by the blank page determination unit 514 matches the result that no image is output by the blank page removal function.

  When the blank page removal function is enabled, the result of the multi-value determination by the blank page determination unit 514 is not “blank page image” but “scan type: BW” is set, and the binary conversion unit 517 Is a "blank image", the BW binary image generated by the binary conversion in the error diffusion mode is output. If the result of the binary determination by the binary conversion unit 517 is not a “blank image”, a BW binary image generated by binary conversion in the simple binary mode is output.

  When the blank page removal function is set to be valid, the result of the multi-level determination by the blank page determination unit 514 is not “blank image”, and the result of the determination by the color number detection unit 515 is “BW image”. If the result of the binary determination by the conversion unit 517 is a “blank image”, a gray Jpeg multivalued image is output. If the result of the binary determination by the binary conversion unit 517 is not a “blank image”, a BW binary image generated by the binary conversion in the simple binary mode is output.

  In the binary conversion in the error diffusion mode or the conversion to the gray Jpeg multi-valued image by the Jpeg compression unit 516, each pixel of the image after the image processing is converted to a white pixel, compared with the binary conversion in the simple binarization mode. Can be suppressed. As a result, it is possible to suppress output of a blank image even though the result of the multi-value determination by the blank sheet determination unit 514 is not a “blank image”. Therefore, it is possible to expect an output result that does not contradict the result of the multi-value determination of the blank page determination unit 514.

  When the free space in the RAM 53 is equal to or larger than the specified amount, the control unit 50 causes the RAM 53 to store the image after the image processing. If the free space in the RAM 53 is smaller than the specified amount, the image after the image processing is not stored in the RAM 53.

  If there is enough free space in the RAM 53, the image after image processing is stored in the RAM 53. Therefore, when it is necessary to output a BW binary image generated by the binary conversion in the error diffusion mode, that is, the result of the multi-level determination by the blank page determination unit 514 is not a “blank image” and the binary If the result of the binary determination by the conversion unit 517 is a “blank image”, the image after image processing stored in the RAM 53 can be used for binary conversion in the error diffusion mode.

  On the other hand, if there is not enough free space in the RAM 53, the image after the image processing is not stored in the RAM 53, so that it is possible to suppress the RAM 53 from being pressed by the image after the image processing. In this case, even if the result of the multi-value determination by the blank page determination unit 514 is not “blank image”, it is impossible to output a BW binary image by binary conversion in the error diffusion mode. If it is determined that the result of the binary determination is a “blank image”, no image is output.

  When “scan type: auto” is set, the number of colors is detected by the number-of-colors detection unit 515, and when the determination result is “BW image”, the output of the gray Jpeg multi-value image is performed. Before being determined, a gray Jpeg multi-valued image has been generated.

  Since the gray Jpeg multi-valued image has been generated in advance, it is possible to expect a high-speed output of the gray Jpeg multi-valued image. That is, when the result of the multi-value determination is not “blank image” and the result of the binary determination is not “blank image”, it can be expected that output consistent with the determination is performed at high speed.

<Second conversion process (2)>

  The second conversion process executed in step S32 shown in FIG. 11 may be the process shown in FIG.

  In the second conversion process shown in FIG. 14, the CPU 51 changes the threshold value used for the binary conversion in the simple binary mode by the function of the binary conversion unit 517 to the low density side (S324). At this time, the CPU 51 creates a histogram of the Y component for the entire image, and changes the threshold so that at least some of the pixels are converted to black pixels.

  Then, the CPU 51 again executes the binary conversion in the simple binarization mode by the function of the binary conversion unit 517 to regenerate the BW binary image (S325).

  Thereafter, the CPU 51 outputs the regenerated BW binary image to an output destination specified in advance (S326), and ends the second conversion process.

  This makes it difficult to output a blank image.

  Note that the second conversion process illustrated in FIG. 14 may be executed in advance before it is determined that the second conversion process is to be executed.

<Second conversion process (3)>

  The second conversion process executed in step S32 shown in FIG. 11 may be the process shown in FIG.

  In the second conversion process illustrated in FIG. 15, the CPU 51 sets, as the operation mode of the Jpeg compression unit 516, a mode for generating only a gray Jpeg multivalued image to be valid (gray) (S327).

  Then, the CPU 51 generates a gray Jpeg multivalued image by the function of the Jpeg compression unit 516 (S328).

  Thereafter, the CPU 51 outputs the gray Jpeg multi-valued image to an output destination designated in advance (S329), and ends the second conversion process.

  Note that the second conversion process illustrated in FIG. 15 may be executed in advance before it is determined that the second conversion process is to be executed.

<Binary determination process (2)>

  When the BW binary image generated by the function of the binary conversion unit 517 is compressed and output, the binary determination process by the binary conversion unit 517 may be the process illustrated in FIG.

  As the number of white pixels included in the BW binary image increases, the compression ratio of the BW binary image increases, and the file size of the compressed BW binary image decreases. Therefore, the CPU 51 determines whether or not the file size of the BW binary image is equal to or larger than a predetermined threshold, for example, 1 kB (kilobyte) (S201).

  When the file size of the BW binary image is equal to or larger than 1 kB (S201: YES), the CPU 51 determines that the BW binary image is not a blank image, and stores the determination result in the RAM 53 (S202).

  If the file size of the BW binary image is smaller than 1 kB (S201: NO), the CPU 51 determines that the BW binary image is a blank image, and stores the determination result in the RAM 53 (S203).

  As described above, by comparing the file size of the compressed BW binary image with the threshold, it is possible to easily determine whether or not the BW binary image is a blank image. In addition, since the method of the binary determination is simple, it is possible to expect a higher speed of the binary determination processing.

<Image output processing (2)>

  The image output process executed in step S7 shown in FIG. 3 may be the process shown in FIG.

  In the image output process shown in FIG. 17, the CPU 51 determines whether “scan type: auto” is set (S721).

  When “scan type: auto” is set, a mode for generating a gray Jpeg multivalued image or a color Jpeg multivalued image is effective as the operation mode of the Jpeg compression unit 516 in the above-described auto setting process (color / Gray), and the binary conversion unit 517 is enabled.

  When “scan type: auto” is set (S721: YES), the CPU 51 determines whether or not the result of the determination by the color number detection unit 515 is “BW image” (S722).

  When the result of the determination by the color number detection unit 515 is “BW image” (S722: YES), the generation of the BW binary image and the binary determination by the function of the binary conversion unit 517 are executed. The generated BW binary image is stored in the RAM 53. Then, the CPU 51 determines whether or not the result of the binary determination by the binary conversion unit 517 is a “blank image” (S723).

  If the result of the binary determination is “blank image” (S723: YES), the CPU 51 deletes the BW binary image stored in the RAM 53 (S724). After deleting the BW binary image, the CPU 51 ends the image output processing.

  If the result of the binary determination is not “blank image” (S723: NO), the CPU 51 outputs the BW binary image stored in the RAM 53 to the output destination specified in advance (S725). The output processing ends.

  On the other hand, when the result of the determination by the color number detection unit 515 is not “BW image” (S722: NO), the CPU 51 determines whether the result of the determination by the color number detection unit 515 is “color image”. Judge (step S726)

  If the result of the determination by the color number detection unit 515 is “color image” (S726: YES), the CPU 51 generates a color Jpeg multivalued image by the function of the Jpeg compression unit 516, and generates the color Jpeg multivalue image. The value image is output to an output destination specified in advance (S727). Then, the CPU 51 ends the image output processing.

  If the result of the determination by the color number detection unit 515 is not “BW image” or “color image” (S726: NO), the CPU 51 uses the function of the Jpeg compression unit 516 to convert the gray Jpeg multi-valued image. Then, the generated gray Jpeg multi-valued image is output to an output destination designated in advance (S728). Then, the CPU 51 ends the image output processing.

  When “scan type: auto” is not set (S721: NO), the CPU 51 determines whether “scan type: BW” is set (S729).

  When “scan type: BW” is set, the binary conversion unit 517 is set to be valid in the above-described item setting processing.

  When “scan type: BW” is set (S729: YES), the generation of the BW binary image and the binary determination by the function of the binary conversion unit 517 are executed. The generated BW binary image is stored in the RAM 53. Then, the CPU 51 determines whether or not the result of the binary determination by the binary conversion unit 517 is a “blank image” (S730).

  If the result of the binary determination is “blank image” (S730: YES), the CPU 51 deletes the BW binary image stored in the RAM 53 (S731). After deleting the BW binary image, the CPU 51 ends the image output processing.

  If the result of the binary determination is not the “blank image” (S730: NO), the CPU 51 outputs the BW binary image stored in the RAM 53 to the output destination specified in advance (S732). The output processing ends.

  When “scan type: BW” is not set (S729: NO), the CPU 51 determines whether “scan type: gray” is set (S733).

  If “scan type: gray” is set, the mode for generating only the gray Jpeg multi-valued image is set to valid (gray) as the operation mode of the Jpeg compression unit 516 in the above-described mono setting process. I have.

  If “scan type: gray” is set (S733: YES), the CPU 51 outputs the gray Jpeg multi-value image created by the function of the Jpeg compression unit 516 to an output destination specified in advance (S734). Then, the image output process ends.

  If none of “scan type: auto”, “scan type: BW” and “scan type: gray” are set, that is, if “scan type: color” is set (S733: NO), In the above-described color setting process, a mode for generating only a color Jpeg multi-value image is set to valid (color) as an operation mode of the Jpeg compression unit 516. In this case, the CPU 51 outputs the color Jpeg multi-valued image created by the function of the Jpeg compression unit 516 to an output destination designated in advance (S735), and ends the image output processing.

  As described above, the result of the multi-value determination by the blank page determination unit 514 is not “blank image”, the result of the determination by the color number detection unit 515 is “BW image”, and the result of the binary determination by the binary conversion unit 517 Is a “blank image”, the BW binary image stored in the RAM 53 is deleted, and no image is output. Also, the result of the multi-value determination by the blank page determination unit 514 is not “blank image”, but “scan type: BW” is set, and the result of the binary determination by the binary conversion unit 517 is “blank image”. In this case, since the BW binary image stored in the RAM 53 is deleted, no image is output. Therefore, the result of the binary determination by the binary conversion unit 517 matches the result that no image is output.

  Therefore, an output result that does not contradict the result of the binary determination by the binary determination process can be expected. That is, it is determined whether or not the BW binary image stored in the RAM 53 as an output image output to the output destination designated in advance is a blank image (binary determination), and the BW binary image is a blank image. If it is determined that there is, the BW binary image is deleted. Therefore, when the blank page removing function is set to be valid, it is possible to suppress the output of the BW binary image, which is a blank page image.

<Modification>

  Although the embodiments of the present invention have been described above, the present invention can be embodied in other forms.

  In the above-described embodiment, the result of the multi-level determination by the blank page determination unit 514 is not “blank image”, but “scan type: auto” is set, and the result of the binary determination by the binary conversion unit 517 is “blank page”. In the case of “image”, a gray Jpeg multi-valued image is output. However, when the result of the binary determination is “blank image” despite that the result of the multi-value determination is not “blank image”, the binary image output shown in FIG. The process may be executed to output a BW binary image generated by the second conversion process (the process shown in FIG. 12 or FIG. 14) during the binary image output process.

  In this case, it is preferable to determine whether to store the image-processed image according to whether the RAM 53 has a sufficient free space in the image-processed image used for the second conversion process.

  In the above-described embodiment, the case where the CPU 51 executes each process has been described. However, the ASIC 55 may execute each process, or the CPU 51 and the ASIC 55 may execute each process in cooperation. Further, the control unit 50 may include a plurality of CPUs, and the plurality of CPUs may execute each process in cooperation.

  Further, a program for each process executed by CPU 51 of MFP 1 may be installed in a PC (computer) connected to the Internet, and the same process as each process executed by CPU 51 may be executed on the PC.

  Furthermore, not only a PC connected to the Internet but also a program (each not shown) connected to the MFP 1 via a LAN (Local Area Network) is installed with a program for each processing executed by the CPU 51 of the MFP 1, In the PC, processes similar to the processes executed by the CPU 51 may be executed.

  Further, in the above-described embodiment, the MFP 1 having the printing function of the image forming unit 10 and the reading function of the image reading unit 20 has been described as an example of the image processing apparatus. , May be a single-function device.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 MFP
20 image reading unit 50 control unit 53 RAM
514 Blank page determination unit 516 JPEG compression unit 517 Binary conversion unit

Claims (7)

An image reading unit;
A control unit;
An operation unit,
With
The control unit includes:
Image acquisition processing for acquiring multi-valued image data generated by reading a document by the image reading unit,
A setting acquisition process for acquiring setting information set via the operation unit, wherein the setting information includes first setting information for outputting as a multi-valued image, and outputting as a multi-valued image or binary. The setting acquisition processing, including second setting information for automatically determining whether to output as an image,
Performing a first blank page determination process of determining whether a multi-value image represented by the multi-value image data acquired by the image acquisition process represents a blank image,
Further, the control unit includes:
A first deletion process for deleting the multi-valued image data when the first blank page determination process determines that the blank image is represented;
A first output process of outputting the multi-valued image when it is determined that the blank image is not represented by the first blank page determination process, and the setting information acquired by the setting acquisition process is the first setting information; ,
If the first blank sheet determination process determines that a blank image is not represented, and the setting information acquired by the setting acquisition process is the second setting information, the multi-valued image data acquired by the image acquisition process is A judgment process of judging whether or not the multivalued image to be represented satisfies a condition for outputting as a binary image;
A second blank page determination process for determining whether a binary image represented by the converted binary image data obtained by binarizing the multi-valued image data represents a blank image when determining that a condition is satisfied in the determination process;
A second deletion process for deleting the binary image when the binary image is determined to be a blank image in the second blank page determination process;
A second output process for outputting the binary image when the binary image is determined not to be a blank image in the second blank page determination process;
An image reading device that executes a third output process of outputting a multi-valued image represented by the multi-valued image data when it is determined that the condition is not satisfied in the determination process . The image reading device according to claim 1 ,
Via the operation unit, accepts a setting operation of whether to enable a blank paper removal function for removing a blank image,
When a setting to enable the blank sheet removal function is received, the first blank sheet determination process is executed,
An image reading device that outputs an output image based on an image acquired by the image acquisition process without performing the first blank page determination process when receiving a setting for disabling the blank page removal function . The image reading apparatus according to claim 1 or 2,
The image reading portion is readable in succession a plurality of originals,
An image reading apparatus that executes the first blank sheet determination process and the determination process for each original. An image reading apparatus according to any one of claims 1 to 3,
The setting information further includes third setting information for outputting as a binary image,
The control unit, when the setting information obtained by the setting obtaining process is the third setting information, obtains binary image data generated by reading a document by the image reading unit in the image obtaining process . And determining whether the binary image represented by the acquired binary image data represents a blank image. An image reading apparatus according to any one of claims 1 to 4,
The control unit includes :
Based on the color difference data of the multi-valued image, determine whether the multi-valued image is chromatic or achromatic,
The multi-value image is determined to achromatic, and the multi-value image, when the luminance component is determined as the pixel at the first threshold or less than the second threshold value or more is contained more than the specified amount, the condition An image reading device that determines that the condition is satisfied. An image reading apparatus according to any one of claims 1 to 5,
The image reading device, wherein the control unit determines whether or not the multi-valued image is a blank image based on luminance component data of the multi-valued image in the first blank paper determination process. An image processing program,
Acquisition processing for acquiring multi-valued image data generated by an image reading device and setting information corresponding to the multi-valued image data ;
Before SL multivalued image and determining the multi-level determination process whether representing a blank image constituting the multi-value image data, cause the computer to execute, further,
A first deletion process for deleting a multi-value image determined to represent a blank image by the multi-value determination process;
When it is determined that the multi-valued image does not represent a blank image by the multi-valued determination process, and the setting information obtained by the obtaining process is first setting information to be output as a multi-valued image, A first output process for outputting the multi-valued image;
Determining that the multi-value image by the previous SL multilevel determination process does not represent a blank image, and automatically whether the setting information acquired by the acquiring process to output on whether the binary image and outputs multi-valued image In the case of the second setting information for judging in, a judgment process of judging whether or not a multi-valued image constituting the multi-valued image data satisfies a condition for outputting as a binary image;
A binary determination process for determining whether the binary image represented by the converted binary image data obtained by binarizing the multi-valued image data is a blank image when it is determined that the condition is satisfied by the determination process When,
A second deletion process of deleting an image in which the binary image is determined to be a blank image by the binary determination process;
A second output process of outputting an output image based on the binary image data, wherein the binary image is an image determined to be not a blank image,
And a third output process of outputting an output image based on the multi-valued image data when it is determined that the condition is not satisfied by the determination process .

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