JP5477964B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus that compresses input image data.

  Conventionally, as an apparatus of this type, as disclosed in Patent Document 1, for example, when a document is read by a reading unit to generate image data and the image data is faxed, the data amount of the image data is reduced. There has been proposed a data processing apparatus that lowers (compresses) the resolution of the image data and transmits the compressed image data by FAX.

Also, as this type of apparatus, for example, when a reading unit having an ADF (Auto Document Feeder) function reads each page of a document consisting of a large number of pages to generate each image data, and print processing based on each page, Since the printing process takes time if each image data remains at a high resolution, a printing processing apparatus that compresses each image data and smoothly performs the printing process based on each compressed image data has been proposed.
In these apparatuses, for example, a reading unit reads a document with high resolution to generate high-quality image data, and then generates low-quality image data in which the image data is reduced to a predetermined resolution.

JP 2008-193742 A

  By the way, in the above apparatus, although each document is a document generated by copying another document or a document generated by facsimile reception, there is a case where a low-quality image is described, and thus the reading unit is uniform. The document is read at a predetermined high resolution to generate image data, and the generated image data is converted to a predetermined low resolution. Therefore, the above-described apparatus has a problem that when the image described in the document has low image quality (unclearness), the degradation of the low-resolution image data generated based on the document is significant.

  In view of the above problems, an object of the present invention is to sequentially convert high-resolution image data generated on the basis of each original into predetermined low-resolution image data, and each of the high-resolution and low-resolution image data. The number of edges (contours) indicating the image quality characteristics of each image data is extracted from the image data, and based on the extracted number of edges, a minimum resolution that does not deteriorate the image quality of the image included in each document is calculated, and at least the calculated minimum An object of the present invention is to provide an image processing apparatus that controls to use image data having a resolution higher than the resolution for processing.

The present invention adopts the following configuration in order to solve the above points.
<Configuration>
An image processing apparatus according to the present invention is an image processing apparatus including a document reading unit that reads original image information described in a document at a predetermined resolution to generate image data, and the generated image data is converted into the resolution of the image data. Each edge portion included in each image data is extracted from the resolution conversion unit for converting to lower-resolution image data, the generated image data, and the converted low-resolution image data, and included in each image data Compare the total number of edges of the generated image data calculated by the edge number calculation unit with the total number of edges of the converted low-resolution image data , and calculate the ratio of the total number of edges. There a preset based on whether the threshold value more than the converted determined lowest resolution determining unit whether it is possible to use a low-resolution image data, the lowest resolution determination unit If judged to be not possible use, the generated image data is determined as the lowest resolution image data, and an output unit for outputting the image data, the lowest resolution determination unit determines that available, low resolution converted to the resolution conversion unit and a control unit for controlling so as to convert the image data to a lower low-resolution image data, the control unit, for each determined the minimum resolution determination unit usable sequentially converted low-resolution to the resolution conversion unit comparison to convert the image data to a lower-resolution image data, the total number of edges of the low-resolution image data obtained by that order next converted to edge number calculation unit, and a total number of edges images data converted into lower resolution It is allowed, and controls to image data converted to a lower resolution to determine whether or not available.

  According to the present invention, when image data is generated by reading original image information described in a document at a predetermined resolution, image data having a lower resolution than the image data is generated, and the generated image data and the converted low-resolution image data are generated. Extract the edge locations included in each image data from the image data, calculate the total number of edge locations included in each image data, and compare the total number of edges in the image data with the total number of edges in the low-resolution image data Determining whether or not the low-resolution image data can be used based on whether or not the ratio of the total number of both edges is equal to or less than a threshold, and if the low-resolution image data is determined to be usable, Since it is controlled to sequentially compare the total number of edges of image data converted to low resolution and converted to low resolution, and the total number of edges of image data of the original resolution converted to low resolution. It can be quality of Motoe information to calculate the lowest resolution that does not deteriorate, and thereby possible to output the image data of the lowest resolution or higher resolution not least deteriorated.

It is a block diagram which shows the control structure of the image processing apparatus 1000 of Example 1 which concerns on this invention. It is a figure which shows an example of the external appearance of the image processing apparatus 1000 of Example 1 which concerns on this invention. 1 is a schematic configuration diagram of an image reading unit 100 according to a first embodiment of the present invention. It is a figure which shows the example of a display of the resolution conversion priority selection screen 30 of Example 1 which concerns on this invention. It is a figure which shows an example of the mask for main scanning directions of the Example 1 which concerns on this invention, and the mask for subscanning directions. It is explanatory drawing of the edge value calculation formula of Example 1 which concerns on this invention. It is a figure which shows the relationship between the image data of Example 1 which concerns on this invention, an edge value, and the total number of edges. It is explanatory drawing of the edge total calculation in the main scanning direction and the subscanning direction with respect to the image data of Example 1 which concerns on this invention. It is a figure which shows the image data which consists of a binary image of the high resolution of Example 1 which concerns on this invention, a medium resolution, and a low resolution. It is explanatory drawing of the edge total calculation in the main scanning direction with respect to the image data of the high resolution of Example 1 which concerns on this invention, a medium resolution, and low resolution. It is explanatory drawing of the total number of edges in the subscanning direction with respect to the image data of the high resolution of the Example 1 which concerns on this invention, a medium resolution, and low resolution. It is a figure which shows an example of a structure of the use resolution conversion table 40 of Example 1 which concerns on this invention. 5 is a flowchart (part 1) illustrating an operation of the image processing apparatus 1000 according to the first exemplary embodiment of the present invention. 6 is a flowchart (part 2) illustrating an operation of the image processing apparatus 1000 according to the first exemplary embodiment of the present invention. It is a block diagram which shows the control structure of the image processing apparatus 1000a of Example 2 which concerns on this invention. It is a flowchart (the 1) which shows operation | movement of the image processing apparatus 1000a of Example 2 which concerns on this invention. It is a flowchart (the 2) which shows operation | movement of the image processing apparatus 1000a of Example 2 which concerns on this invention. It is a flowchart (the 3) which shows operation | movement of the image processing apparatus 1000a of Example 2 which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a description will be given by taking as an example a case where the image processing apparatus is installed and operated in an office of a multifunction peripheral (having a printing function and a scanner function).

<Configuration of Example 1>
FIG. 2 is a diagram illustrating an example of an appearance of the image processing apparatus 1000 according to the first embodiment of the present invention.
As shown in FIG. 2, the image processing apparatus 1000 reads an original placed on the manual feed tray 1011 or the original glass plate 1021 (see FIG. 3) and generates predetermined high-resolution image data. And an image forming unit 200 that prints and forms a toner image based on the image data generated by the image reading unit 100 on a sheet.
Note that the image processing apparatus 1000 has interfaces for connecting a portable memory such as a USB memory (not shown) or connecting to a user terminal (PC: Personal Computer, etc.) via a network. As a result, the image processing apparatus 1000 generates image data of the use resolution generated based on the document read by the image reading unit 100 and stored in the image storage unit 108 (see FIG. 1), which will be described later, from the portable memory or the user. It is also possible to store in a predetermined memory of the terminal.
For example, when the image processing apparatus 1000 has a facsimile transmission / reception function, the image processing apparatus 1000 is connected to an analog public line network and an IP network via a VoIP adapter (not shown), and can perform facsimile communication with other facsimile apparatuses. Is possible.

FIG. 3 is a schematic configuration diagram of the image reading unit 100 according to the first embodiment of the present invention.
Next, the configuration of the image reading unit 100 will be described in detail with reference to FIG.
As shown in FIG. 3, the image reading unit 100 includes an automatic document feeding unit 101 and a document reading unit 102.
The automatic document feeder 101 is integrally formed with the cover of the image processing apparatus 1000 shown in FIG.
As shown in FIG. 3, the document reading unit 102 is disposed below the automatic document feeding unit 101, and a document glass for placing a document is placed on the upper part in contact with the automatic document feeding unit 101. A plate 1021 is included.
The automatic document feeder 101 formed integrally with the cover is disposed so as to be openable and closable with respect to the document reading unit 102 so that the user can place the document on the document glass plate 1021.

The automatic document feeder 101 is a portion for automatically feeding and conveying the document placed on the manual feed tray 1011 and discharging it to the document discharge table 1019.
The document reading unit 102 is a unit for optically reading a document conveyed by the automatic document feeding unit 101 or a document placed on the document glass plate 1021 to generate image data.

First, the configuration of the automatic document feeder 101 will be described in detail with reference to FIG.
When a document is placed on the manual feed tray 1011, the document detection sensor 1012 is turned on.
Thereafter, when the user operates the user interface unit 105 and presses a “start” button (not shown) indicating a “document reading” instruction, the reading control unit 103 (see FIG. 1) includes a paper feed roller 1013, a conveyance roller A voltage from a power supply unit (not shown) is supplied to a stepping motor 1016 connected to the pair 1014 and the discharge roller 1015 with a gear structure (not shown) to rotate these rollers.

  When the rotation of the paper feeding roller 1013 starts, the paper feeding roller 1013 feeds the page positioned at the top of the pages of the document placed on the manual feed tray 1011 and feeds it in the direction of the conveying roller pair 1014.

  When the rotation of the pair of conveying rollers 1014 starts, the document fed from the sheet feeding roller 1013 is conveyed toward the document pressing plate 1017.

As shown in FIG. 3, a reading position sensor 1018 is disposed in front of the conveyance roller pair 1014.
The reading position sensor 1018 is a part for detecting the reading start timing of the original in the reading unit 1022 so that the original conveyed by the conveyance roller pair 1014 can be read by a later-described reading unit 1022 of the original reading unit 102.

The document pressing plate 1017 is a portion that presses and presses the document in the direction of the document glass plate 1021 so that the document transported from the transport roller pair 1014 can be read by the reading unit 1022.
While the document pressing plate 1017 is sequentially pressed from the leading edge to the trailing edge of the document, an image included in the document is read by the reading unit 1022 and image data for each page of each document is generated.
The configuration of the reading unit 1022 will be described in detail later.
The document that has passed through the document pressing plate 1017 is transported in the direction of the discharge roller 1015 based on the rotation of the transport roller pair 1014.

The discharge roller 1015 is used for discharging the automatically fed document onto the document discharge table 1019.
In other words, when the discharge roller 1015 starts to rotate, the document transported from the transport roller pair 1014 is transported to the document discharge table 1019.
After that, when the automatic document feeder 101 finishes automatically feeding all pages of the document and discharges all the pages from the discharge roller 1015 to the document discharge table 1019, the reading control unit 103 performs stepping from a power supply unit (not shown). The voltage supply to the motor 1016 is stopped. As a result, the rotation of the paper feed roller 1013, the conveyance roller pair 1014, and the discharge roller 1015 is stopped.

Next, the configuration of the document reading unit 102 will be described in detail with reference to FIG.
The reading unit 1022 generates image data by optically reading an image pressed on a document pressed on the document glass plate 1021 by the document pressing plate 1017 or a document placed on the document glass plate 1021. It is.
That is, as shown in FIG. 3, the reading unit 1022 includes a light source 10221 for irradiating a document fed from the automatic document feeder 101 or a document placed on the document glass plate 1021. Reflecting mirror 10222 and reflecting mirror 10223 for changing the optical path of the light reflected by the document, lens 10224 for condensing the light whose optical path has been changed, and photoelectric conversion of the light collected by lens 10224, in accordance with the image A CCD (Charge Coupled Device) sensor 10225 that generates voltage is used to optically read an image written on a document using each unit to generate image data.

  As shown in FIG. 3, the reading unit 1022 is fixed to a driving belt 1025 wound around a stepping motor 1023 and a pulley 1024, and along the original glass plate 1021 based on the travel of the driving belt 1025. It has a movable configuration.

In order to control the movement of the reading unit 1022, a home sensor 1026 is provided as shown in FIG.
The home sensor 1026 is a reading unit that moves between a home position that is a starting point for starting the operation of the reading unit 1022 and a return position that starts moving to the home position on the opposite side of the home position. This is a sensor for detecting the moving position of 1022.

When the reading position sensor 1018 detects the leading edge of the document, the reading control unit 103 supplies a voltage from a power source (not shown) to the stepping motor 1023 so that the reading unit 1022 is positioned immediately below the document pressing plate 1017. 1025 is started and a voltage from a power source (not shown) is supplied to the reading unit 1022 to operate the unit.
Thereafter, based on the position detection of the reading unit 1022 from the home sensor 1026, the reading control unit 103 supplies a voltage from a power source (not shown) to the stepping motor 1023 when the reading unit 1022 reaches a position directly below the document pressing plate 1017. To stop. As a result, the reading unit 1022 stops just below the document pressing plate 1017.
The reading unit 1022 stopped just below the document pressing plate 1017 optically reads the document fed by the automatic document feeder 101 from the leading edge to the trailing edge, and generates image data.
When the reading unit 1022 finishes generating image data based on all the pages of the document placed on the manual feed tray 1011, the reading unit 1022 supplies a voltage from a power supply (not shown) to the stepping motor 1023 based on the control of the reading control unit 103. Move to home position.
The reading unit 1022 that has moved to the home position stops the supply of voltage from a power source (not shown) based on the control of the reading control unit 103.

On the other hand, the reading control unit 103 detects that a document is placed on the document glass plate 1021 by opening and closing the automatic document feeding unit 101 integrally formed with the cover (detected by a cover open sensor), and the above “ When the pressing of the “Start” button is detected, a voltage from a power source (not shown) is supplied to the stepping motor 1023 and a voltage from a power source (not shown) is supplied to the reading unit 1022 to move the reading unit 1022 from the home position to the folding position. Then, the unit is operated.
The reading unit 1022 that moves from the home position to the turn-back position optically reads the document placed on the document glass plate 1021 from the front end to the rear end, and generates image data.
When the reading unit 1022 moves to the folding position and finishes generating image data based on the document placed on the document glass plate 1021, a power source (not shown) supplies power to the stepping motor 1023 based on the control of the reading control unit 103. When the voltage is supplied, it moves to return to the home position.
The reading unit 1022 that has returned to the home position stops the supply of voltage from a power source (not shown) based on the control of the reading control unit 103.

  The white correction plate 1027 is used by the CCD sensor 10225 to read in order to obtain a voltage value corresponding to a white image used in the shading correction process for smoothing variations in the voltage output from the CCD sensor 10225 as a reference value. As shown in FIG. 3, it is arranged outside the reading range of the original (outside the range of the original glass plate 1021).

FIG. 1 is a block diagram illustrating a control configuration of the image processing apparatus 1000 according to the first embodiment of the present invention.
Next, the control configuration of the image reading unit 100 will be described in detail with reference to FIG.
As shown in FIG. 1, the image reading unit 100 includes an automatic document feeding unit 101, a document reading unit 102, a reading control unit 103 for controlling the entire image reading unit 100, an image forming unit 200, and a network. An interface (I / F) unit 104, a user interface unit 105, a resolution conversion priority selection screen storage unit 106, a resolution conversion priority selection result storage unit 107, and an image storage unit 108, an edge number calculation unit 109, an edge number storage unit 110, a resolution conversion unit 111, a minimum resolution determination unit 112, a use resolution determination unit 113, and a use resolution conversion table storage unit 114.

The user interface unit 105 is an input display unit including a touch panel display as shown in FIG. 2 and a plurality of buttons.
The user interface unit 105 includes a “copy” button and a “scanner” button (not shown) for the user to select either “copy” or “scanner” processing.
Further, the user interface unit 105 includes a “start” button for instructing the start of the process after the user selects the “copy” or “scanner” process.
That is, the user interface unit 105 displays various messages to the user on the display and receives various setting inputs from the user.
When the user interface unit 105 detects that the “copy” button or the “scanner” button is pressed, the user interface unit 105 transmits a detection signal to the reading control unit 103.

  The automatic document feeder 101 integrally formed with the cover is opened upward by the user, the document is placed on the document glass plate 1021, and then the cover is closed. The cover open sensor that does not detect the placement of the document. The cover open sensor transmits a detection signal to the reading control unit 103 when detecting the placement of the document.

  On the other hand, when a document is placed on the manual feed tray 1011, the document detection sensor 1012 detects the placement of the document. When the document detection sensor 1012 detects the placement of the document, the document detection sensor 1012 transmits a detection signal to the reading control unit 103.

FIG. 4 is a diagram illustrating an example of the resolution conversion priority selection screen 30 according to the first embodiment of the present invention.
The resolution conversion priority selection screen storage unit 106 is a part for storing a “resolution conversion priority selection screen 30” for prompting the user to select resolution conversion priority as shown in FIG.
Upon receiving the document placement detection signal, the reading control unit 103 reads the resolution conversion priority selection screen 30 from the resolution conversion priority selection screen storage unit 106 so that the user can select “resolution conversion priority”. The information is displayed on a touch panel display included in the user interface unit 105.

  When the “resolution conversion priority selection screen 30” as shown in FIG. 4 is displayed on the touch panel display, the user selects “priority for resolution conversion of the document image” displayed on the screen. ”Is selected, and one of the“ strong ”button 32,“ weak ”button 33, and“ none ”button 34 is selected.

The definition of “strong”, “weak”, and “none” in “resolution conversion priority” will be described with reference to FIG.
As shown in FIG. 4, “resolution conversion priority = strong” is a method in which the resolution of the image data (original image) is reduced to the lowest resolution that does not deteriorate the image, and the data capacity size is compressed to the minimum size. This is an item (low resolution, small data capacity size) to be selected when the user desires to generate image data with high image quality.
“Resolution conversion priority = low”, as shown in FIG. 4, the user desires to generate image data that slightly reduces the resolution of the image data and slightly compresses the data capacity size, that is, slightly lowers the image quality level. This is an item to be selected (medium resolution, medium data size).
As shown in FIG. 4, “resolution conversion priority = none” is an item selected when the user desires to generate high-quality image data without reducing the resolution of the image data and compressing the data size. (High resolution, large data capacity).

The resolution conversion priority selection result storage unit 107 allows the user to select one of the “strong” button 32, “weak” button 33, and “none” button 34 displayed on the “resolution conversion priority selection screen 30”. This is a part for storing the selected selection result (any one of “strong”, “weak”, and “none”).
The data stored in this storage unit is sequentially overwritten and erased.

  When the user selects one of the buttons “strong”, “weak”, and “none”, the reading control unit 103 converts the selection result (any one of “strong”, “weak”, and “none”) into a resolution. Store in the priority selection result storage unit 107.

  Further, when the selection of any one of the “strong”, “weak”, and “none” buttons is input to the user interface unit 105, when the “copy” button is selected, Displays a print setting screen (not shown) for setting the print density, print size, print paper, number of prints, and the like based on the control of the reading control unit 103, and the user refers to the print setting screen to Set up.

  On the other hand, when the “scanner” button is selected, a scan setting screen (not shown) for setting a scan size and the like is displayed on the display based on the control of the reading control unit 103, and the user Performs various settings with reference to the scan setting screen.

  Thereafter, when the user presses the “start” button, the reading control unit 103 controls the automatic document feeding unit 101 to feed a document when receiving a detection signal from the document detection sensor 1012. Then, the document reading unit 102 performs control to read the fed document and generate image data.

  On the other hand, when receiving a detection signal from a cover open sensor (not shown), the reading control unit 103 controls the document reading unit 102 to read the document placed on the document glass plate 1021 and generate image data. Do.

The image storage unit 108 is a part that stores high-resolution (600 dpi in this embodiment) image data read by the document reading unit 102.
The image storage unit 108 stores image data every time the resolution conversion unit 111 generates image data of each resolution.
Here, each resolution (for example, 600 dpi, 300 dpi, 150 dpi, and 75 dpi) is assigned to the image data of each resolution stored in the image storage unit 108 as identification information.

When the document reading unit 102 reads the document and generates image data, the reading control unit 103 stores the generated high-resolution image data in the image storage unit 108.
When the reading control unit 103 stores the high-resolution image data, if the priority selection result stored in the resolution conversion priority selection result storage unit 107 is “none”, the reading resolution unit 103 displays “ The notification of “resolution conversion unnecessary” and the priority selection result (none) are transferred.

  On the other hand, when the stored resolution conversion priority selection result is “strong” or “weak”, the reading control unit 103 instructs the edge number calculation unit 109 to calculate the number of edges.

FIG. 5 is a diagram illustrating an example of a main scanning direction mask and a sub scanning direction mask according to the first embodiment of the present invention.
The edge number calculation unit 109 is a part that calculates the number of edges (contours) indicating the image quality characteristics of the image data based on each pixel included in the image data of each resolution.
That is, when the edge number calculation unit 109 receives an instruction to calculate the number of edges, the image processing apparatus 1000 has a memory (not shown) for the image data having the lowest resolution among the image data stored in the image storage unit 108. A mask (main scanning direction mask) for determining the edge value in the main scanning direction as shown in FIG. 5A and the edge value in the sub scanning direction as shown in FIG. First, an edge value in the main scanning direction and an edge value in the sub-scanning direction are respectively calculated by applying respective masks (masks for sub-scanning direction) to be obtained.

FIG. 6 is an explanatory diagram of an edge value calculation formula according to the first embodiment of the present invention.
When edge values are calculated by applying a specific mask consisting of determinants (M1 to M9) of 3 rows × 3 columns to image data consisting of pixels (P1 to P9) of 3 rows × 3 columns shown in FIG. An example will be described.
In the above case, the edge value Val (P5) for the pixel P5 is calculated by multiplying the surrounding pixels including P5 by the specific mask.
Here, the edge value Val (P5) is calculated by the following (formula 1).

Val (P5) = ΣPn × Mn (Equation 1)
(N = 1-9)

FIG. 7 is a diagram illustrating a relationship among the image data, the edge value, and the total number of edges according to the first embodiment of the present invention.
The upper diagram in FIG. 7 shows image data composed of three rows of binary images. Here, 0 in the upper diagram represents a white pixel, and 1 represents a black pixel.
When the main scanning direction mask shown in FIG. 5A is applied to each pixel in the second row from the top of the image data, each edge value shown in the lower diagram of FIG. 7 is calculated. In FIG. 7, pixels having edge values equal to or greater than a predetermined threshold (2 in this embodiment) are shown in gray. The pixels shown in gray are the edges (contours) of the image data, and the total number of edges is “4” in this figure.

FIG. 8 is an explanatory diagram for calculating the total number of edges in the main scanning direction and the sub-scanning direction for the image data according to the first embodiment of the invention.
FIG. 8A shows image data composed of binary images.
FIG. 8B shows the edge value of each pixel and the total number of edges in the main scanning direction when the main scanning direction mask shown in FIG. 5A is applied to the image data shown in FIG. FIG.
FIG. 8C shows the edge value of each pixel and the total number of edges in the sub-scanning direction when the sub-scanning direction mask shown in FIG. 5B is applied to the image data shown in FIG. FIG.
After calculating the edge value in the main scanning direction and the edge value in the sub-scanning direction for each pixel included in the image data, the edge number calculating unit 109 then calculates the total number of edges in the main scanning direction and the sub-scanning direction. The total number of edges is calculated.

When the edge value of each pixel is calculated by applying the main scanning direction mask shown in FIG. 5A to the image data composed of the binary image shown in FIG. 8A, each of the image data shown in FIG. Value.
In each edge value of each pixel shown in FIG. 8B, a pixel having an edge value equal to or greater than a specific threshold value (2 in this embodiment) is determined as an edge (contour). Pixels that are edges are shown in gray in FIG. 8B.
The total number of edges in the main scanning direction (32 in this embodiment) included in the image data shown in FIG. 8B is calculated.

Similarly, when the edge value of each pixel is calculated by applying the sub-scanning direction mask shown in FIG. 5B to the image data shown in FIG. 8A, each value shown in FIG. Become.
In each edge value of each pixel shown in FIG. 8C, a pixel having an edge value equal to or greater than a specific threshold value (2 in this embodiment) is determined as an edge (contour). Pixels that are edges are shown in gray in FIG.
The total number of edges in the sub-scanning direction (32 in this embodiment) included in the image data shown in FIG.

Each time the edge number calculation unit 109 calculates the total number of edges in the main scanning direction and the total number of edges in the sub scanning direction in the image data of each resolution, the reading control unit 103 determines the resolution of the image data and the main scanning direction. And the edge value in the sub-scanning direction are stored in the edge number storage unit 110.
In the present embodiment, the edge number calculation unit 109 determines each edge (contour) from the edge value in the main scanning direction and each edge value in the sub-scanning direction for all pixels included in the image data of each resolution, and the edge Although the configuration is such that the total number is calculated, the present invention is not limited to this, and the configuration is such that each edge included in a certain range that has moved a predetermined area from the point where the edge was first determined is determined, and the total number of edges is calculated. May be.

The edge number storage unit 110 is a part that stores the total number of edges in the main scanning direction and the total number of edges in the sub scanning direction in the image data of each resolution calculated by the edge number calculation unit 109 in association with each resolution.
The total number of both edges of each resolution stored in the edge number storage unit 110 is deleted from the storage unit under the control of the reading control unit 103 when the minimum resolution determination unit 112 determines the minimum resolution.

  When the reading control unit 103 stores the number of both edges of the high-resolution (600 dpi) image data, the reading control unit 103 instructs the resolution conversion unit 111 to perform resolution conversion.

  On the other hand, when the reading control unit 103 stores the number of both edges of the image data of medium resolution (300 dpi) or low resolution (150 dpi, 75 dpi), it instructs the minimum resolution determination unit 112 to determine the minimum resolution.

The resolution conversion unit 111 is a part that converts the image data having the lowest resolution among the image data stored in the image storage unit 108 into image data having a lower resolution.
In other words, when the resolution conversion unit 111 receives an instruction for resolution conversion, if the image data stored in the image storage unit 108 is only high-resolution (600 dpi) image data, the high-resolution image data is converted to medium resolution. Conversion to (300 dpi) image data.

  On the other hand, if the lowest resolution image data among the image data stored in the image storage unit 108 is medium resolution (300 dpi) image data, the resolution conversion unit 111 reduces the medium resolution image data. The image data is converted into resolution (150 dpi) image data.

Further, when the lowest resolution image data among the image data stored in the image storage unit 108 is low resolution (150 dpi) image data, the resolution conversion unit 111 further outputs the low resolution image data. Convert to low resolution (75 dpi) image data.
Here, the resolution is given as identification information to the image data of each resolution converted by the resolution conversion unit 111.

Each time the resolution conversion unit 111 generates image data of each resolution, the reading control unit 103 stores the generated image data of each resolution in the image storage unit 108.
The reading control unit 103 instructs the edge number calculation unit 109 to calculate the number of edges every time image data of each resolution converted by the resolution conversion unit 111 is stored.

FIG. 9 is a diagram illustrating image data including binary images of high resolution, medium resolution, and low resolution according to the first embodiment of the present invention.
FIG. 10 is an explanatory diagram for calculating the total number of edges in the main scanning direction for high resolution, medium resolution, and low resolution image data according to the first embodiment of the present invention.
FIG. 11 is an explanatory diagram for calculating the total number of edges in the sub-scanning direction for high resolution, medium resolution, and low resolution image data according to the first embodiment of the present invention.
The minimum resolution determination unit 112 is a part that determines the minimum resolution that can be resolved without degrading the image described in each document.
That is, when receiving the resolution determination instruction, the lowest resolution determination unit 112 receives the resolution having the lowest resolution among the total number of edges in the main scanning direction and the total number of edges in the sub scanning direction of each resolution stored in the edge number storage unit 110. The total number of edges is compared with the total number of edges having the second lowest resolution, and based on whether the ratio of the total number of edges is equal to or greater than a preset threshold value (1/3 in this embodiment). Then, it is determined whether or not the image data having the lowest resolution can be used.
The minimum resolution determination unit 112 has a count function for counting the number of determinations, and performs determination until the number of counts reaches a preset maximum number (3 in this embodiment).

  When the lowest resolution determination unit 112 determines that the image data with the lowest resolution stored in the edge number storage unit 110 can be used, the resolution conversion unit if the determination number is not the maximum number (3 in the present embodiment). 111 is instructed to convert the resolution.

  On the other hand, when the minimum resolution determination unit 112 determines that it can be used, when the determination number is the maximum number, the lowest resolution stored in the edge number storage unit 110 is determined to be the minimum resolution.

  If the lowest resolution determination unit 112 determines that the image data having the lowest resolution is unusable, the lowest resolution determination unit 112 determines that the second lowest resolution stored in the edge number storage unit 110 is the minimum resolution.

  When the minimum resolution determination unit 112 determines the minimum resolution, the reading control unit 103 instructs the use resolution determination unit 113 to determine the use resolution and transfers the determination result (minimum resolution).

How the minimum resolution determination unit 112 determines the minimum resolution will be described in detail below with reference to the drawings.
When the main scanning direction mask as shown in FIG. 5A is applied to the image data composed of the high-resolution binary image shown in FIG. 9A, the edge value of each pixel included in the image data is Each value is as shown in FIG.
In FIG. 10A, the total number of edges T_edge_horz_high (the number of pixels corresponding to an edge value equal to or greater than the threshold value 2) calculated by the edge number calculation unit 109 is 96.

On the other hand, when the sub-scanning direction mask as shown in FIG. 5B is applied to the image data shown in FIG. 9A, the edge value of each pixel included in the image data is as shown in FIG. It becomes each value as shown in.
In FIG. 11A, the total number of edges T_edge_vert_high calculated by the edge number calculation unit 109 in the sub-scanning direction is 96.

Next, when the main scanning direction mask as shown in FIG. 5A is applied to the image data composed of the binary image having the medium resolution shown in FIG. 9B, each pixel included in the image data is displayed. The edge value becomes each value as shown in FIG.
In FIG. 10B, the total number of edges T_edge_horz_mid in the main scanning direction calculated by the edge number calculation unit 109 is 52.

On the other hand, when the sub-scanning direction mask as shown in FIG. 5B is applied to the image data shown in FIG. 9B, the edge value of each pixel included in the image data is as shown in FIG. It becomes each value as shown in.
In FIG. 11B, the total number of edges T_edge_vert_mid in the sub-scanning direction calculated by the edge number calculation unit 109 is 52.

Next, when the main scanning direction mask as shown in FIG. 5A is applied to the image data composed of the low-resolution binary image shown in FIG. 9C, each pixel included in the image data is displayed. The edge value becomes each value as shown in FIG.
In FIG. 10C, the total number of edges T_edge_horz_low in the main scanning direction calculated by the edge number calculating unit 109 is 12.

On the other hand, when the sub-scanning direction mask as shown in FIG. 5B is applied to the image data shown in FIG. 9C, the edge value of each pixel included in the image data is as shown in FIG. It becomes each value as shown in.
In FIG. 11C, the total number T_edge_vert_low in the sub-scanning direction calculated by the edge number calculation unit 109 is 12.

First, the minimum resolution determination unit 112 has a ratio of the total number of edges in the main scanning direction of the medium resolution image data shown in FIG. 10B to the total number of edges in the main scanning direction of the high resolution image data shown in FIG. Is greater than or equal to a preset threshold value Th_edge_horz_res (1/3 in this embodiment).

T_edge_horz_mid / T_edge_horz_high (52/96 in this embodiment)> = Th_edge_horz_res (1/3 in this embodiment)

In the example shown in FIGS. 10A and 10B, the above formula is satisfied.

Similarly, the minimum resolution determination unit 112 calculates the total number of edges in the sub-scanning direction of the medium-resolution image data shown in FIG. 11B with respect to the total number of edges in the sub-scanning direction of the high-resolution image data shown in FIG. It is determined whether or not the ratio is equal to or greater than a preset threshold Th_edge_vert_res (1/3 in this embodiment).

T_edge_vert_mid / T_edge_vert_high (52/96 in this embodiment)> = Th_edge_vert_res (1/3 in this embodiment)

In the example shown in FIGS. 11A and 11B, the above formula is satisfied.

  When the total number of edges in the main scanning direction and the sub-scanning direction included in the high-resolution and medium-resolution image data satisfies the above formula, the minimum resolution determination unit 112 determines that the medium-resolution image data can be used. .

  On the other hand, if the above equation is not satisfied, the lowest resolution determination unit 112 determines that the medium resolution image data cannot be used. Accordingly, the minimum resolution determination unit 112 determines that high resolution = the minimum resolution that does not deteriorate the image described in the document.

Next, the lowest resolution determination unit 112 calculates the total number of edges in the main scanning direction of the low resolution image data illustrated in FIG. 10C with respect to the total number of edges in the main scanning direction of the medium resolution image data illustrated in FIG. It is determined whether or not the ratio is greater than or equal to a preset threshold Th_edge_horz_res (1/3 in this embodiment).

T_edge_horz_low / T_edge_horz_mid (12/52 in this embodiment)> = Th_edge_horz_res (1/3 in this embodiment)

In the example shown in FIGS. 10B and 10C, the above formula is not satisfied.

Similarly, the minimum resolution determination unit 112 calculates the total number of edges in the sub-scanning direction of the low-resolution image data shown in FIG. 11C with respect to the total number of edges in the sub-scanning direction of the medium-resolution image data shown in FIG. It is determined whether or not the ratio is equal to or greater than a preset threshold Th_edge_vert_res (1/3 in this embodiment).

T_edge_vert_low / T_edge_vert_mid (12/52 in this embodiment)> = Th_edge_vert_res (1/3 in this embodiment)

In the examples shown in FIGS. 11B and 11C, the above formula is not satisfied.

  The lowest resolution determination unit 112 determines that the low resolution can be used when the total number of edges in the main scanning direction and the sub scanning direction included in the medium resolution and low resolution image data satisfies the above formula.

  On the other hand, if the above equation is not satisfied, the lowest resolution determination unit 112 determines that the low-resolution image data cannot be used. Thereby, the minimum resolution determination unit 112 determines that the medium resolution = the minimum resolution that does not deteriorate the image described in the document.

  In this embodiment, the medium resolution (300 dpi) is halved with respect to the high resolution (600 dpi). Similarly, the low resolution (150 dpi) with respect to the medium resolution (300 dpi) Is halved. As described above, when the resolution is halved, the number of edges included in the image data is considered to be simply halved. Based on this, in this embodiment, 1/3 obtained by subtracting the plus alpha component from 1/2 was set as the threshold values (Th_edge_horz_res and Th_edge_vert_res).

FIG. 12 is a diagram illustrating the configuration of the use resolution conversion table 40 according to the first embodiment of the present invention.
The use resolution determination unit 113 stores the use resolution corresponding to the “resolution conversion priority” selected by the user and the “minimum resolution” determined by the minimum resolution determination unit 112 in the use resolution conversion table storage unit 114 in advance. This is a part to be searched from the stored use resolution conversion table 40.
First, the use resolution conversion table 40 used by the use resolution determination unit 113 to determine the use resolution will be described in detail with reference to FIG.
As shown in FIG. 12, the used resolution conversion table 40 includes each minimum resolution (600 dpi, 300 dpi) determined by the minimum resolution determination unit 112 when the resolution conversion priority selected by the user is “strong” or “weak”. , 150 dpi, 75 dpi) and the used resolution (high resolution) to be used when the selected resolution conversion priority is “none”.
In other words, when the use resolution determination unit 113 receives “minimum resolution” together with an instruction to determine use resolution, the resolution conversion priority selection result (“strong”, “ The use resolution corresponding to the “low resolution” and the “minimum resolution” is searched from the use resolution conversion table 40 stored in the use resolution conversion table storage unit 114 to determine the use resolution.

  On the other hand, when the user selects resolution conversion priority = none via the user interface unit 105, the use resolution determination unit 113 receives the resolution conversion priority = none along with an instruction “resolution conversion unnecessary”. The resolution conversion table 40 is searched, and the corresponding high resolution (600 dpi) is determined as the use resolution.

  When the use resolution determination unit 113 determines the use resolution, the reading control unit 103 displays the image data of the use resolution stored in the image storage unit 108 when the user selects the “copy” button. To the image forming unit 200. As a result, the image forming unit 200 performs print processing based on the image data of the determined use resolution. When the printing process is completed, the image forming unit 200 transmits the completion notification to the image reading unit 100. When receiving the completion notification via the I / F unit 104, the image reading unit 100 deletes the image data of each resolution based on the document stored in the image storage unit 108 from the storage unit.

  On the other hand, when the user selects the “scanner” button, the reading control unit 103 leaves only the image data of the resolution corresponding to the used resolution stored in the image storage unit 108 and the image data of other resolutions. If stored, the image data of another resolution is deleted from the storage unit. Thereby, only the image data of the use resolution is stored in the image storage unit 108. Here, when the image data of each page of the document fed from the automatic document feeding unit 101 is sequentially stored in the image storage unit 108, the image data of each page is based on the control of the reading control unit 103. It is stored in association with one piece of related data.

<Operation of Example 1>
FIG. 13 is a flowchart showing the operation of the image processing apparatus 1000 according to the first embodiment of the present invention.
The operation of the image processing apparatus 1000 will be described in detail with reference to FIG.
The automatic document feeder 101 integrally formed with the cover is opened upward by the user, the document is placed on the document glass plate 1021, and then the cover is closed. The cover open sensor that does not detect the placement of the document (step S101). The cover open sensor transmits a detection signal to the reading control unit 103 when detecting the placement of the document.

  On the other hand, when a document is placed on the manual feed tray 1011, the document detection sensor 1012 detects the placement of the document. When the document detection sensor 1012 detects the placement of the document, the document detection sensor 1012 transmits a detection signal to the reading control unit 103.

  Further, when the user interface unit 105 detects that the user presses the “copy” button or the “scanner” button, the user interface unit 105 transmits a detection signal to the reading control unit 103.

  When the reading control unit 103 receives the detection signal, the reading control unit 103 reads the resolution conversion priority selection screen 30 from the resolution conversion priority selection screen storage unit 106 and causes the user interface unit 105 to select the “resolution conversion priority”. Is displayed on the touch panel display of the (step S102).

  When the “resolution conversion priority selection screen 30” as shown in FIG. 4 is displayed on the touch panel display, the user selects “priority for resolution conversion of the document image” displayed on the screen. ”Is selected, and one of the“ strong ”button 32, the“ weak ”button 33, and the“ none ”button 34 is selected (step S103).

  When the user selects one of the buttons “strong”, “weak”, and “none”, the reading control unit 103 converts the selection result (any one of “strong”, “weak”, and “none”) into a resolution. Store in the priority selection result storage unit 107.

  Further, when the selection of any one of the “strong”, “weak”, and “none” buttons is input to the user interface unit 105, when the “copy” button is selected, Based on the control of the reading control unit 103, a print setting screen (not shown) for setting the print density, print size, print paper, number of prints, and the like is displayed. The user refers to the print setting screen and makes various settings. I do.

  On the other hand, when the “scanner” button is selected, a scan setting screen (not shown) for setting a scan size and the like is displayed on the display based on the control of the reading control unit 103. Various settings are made with reference to the scan setting screen.

  Thereafter, when the user presses a “start” button of the user interface unit 105 (step S104), when the reading control unit 103 receives a detection signal from the document detection sensor 1012, the automatic document feeder 101 Control is performed to feed the document, and the document reading unit 102 performs control to read the fed document and generate image data (step S105).

  On the other hand, when receiving a detection signal from a cover open sensor (not shown), the reading control unit 103 controls the document reading unit 102 to read the document placed on the document glass plate 1021 and generate image data. Do.

When the document reading unit 102 reads the document and generates image data, the reading control unit 103 stores the generated high-resolution image data in the image storage unit 108.
When the reading control unit 103 stores the high-resolution image data, if the priority selection result stored in the resolution conversion priority selection result storage unit 107 is “none” (step S106), the use resolution determination is performed. The notification of “resolution conversion unnecessary” and the priority selection result (none) are transferred to the unit 113.

  On the other hand, when the stored resolution conversion priority selection result is “strong” or “weak”, the reading control unit 103 instructs the edge number calculation unit 109 to calculate the number of edges.

  When the user selects resolution conversion priority = None via the user interface unit 105 and receives a resolution conversion priority = None together with an instruction “resolution conversion unnecessary”, the use resolution determination unit 113 converts the use resolution. The used resolution conversion table 40 stored in the table storage unit 114 is searched, and the corresponding high resolution (600 dpi) is determined as the used resolution (step S107).

  When the use resolution determination unit 113 determines use resolution = high resolution, the reading control unit 103, when the user selects the “copy” button (step S108), the image of the use resolution stored in the image storage unit 108. Data is transferred to the image forming unit 200 via the I / F unit 104. As a result, the image forming unit 200 performs a printing process based on the image data of the determined use resolution (step S109). When the printing process is completed, the image forming unit 200 transmits the completion notification to the image reading unit 100. Upon receiving the completion notification via the I / F unit 104, the image reading unit 100 deletes the high-resolution image data stored in the image storage unit 108 from the storage unit.

  On the other hand, when the user selects the “scanner” button, the reading control unit 103 leaves the high-resolution image data stored in the image storage unit 108 as it is (step S110). At this time, when the image data of each page of the document placed on the manual feed tray 1011 is sequentially stored in the image storage unit 108, the image data of each page is associated with the associated 1 under the control of the reading control unit 103. Are stored in association with each other. The image data stored in the image storage unit 108 is then stored in, for example, a USB memory connected via an interface (not shown) of the image processing apparatus 1000 based on a user operation via the user interface unit 105. And deleted from the storage unit.

  When receiving the instruction to calculate the number of edges, the edge number calculation unit 109 pre-stores image data having the lowest resolution among the image data stored in the image storage unit 108 in a memory (not shown) of the image processing apparatus 1000. A mask (main scanning direction mask) for obtaining the set edge value in the main scanning direction as shown in FIG. 5A and a sub scanning direction edge value as shown in FIG. 5B. First, an edge value in the main scanning direction and an edge value in the sub scanning direction are respectively calculated (step S111).

  Each time the edge number calculation unit 109 calculates the total number of edges in the main scanning direction and the total number of edges in the sub scanning direction in the image data of each resolution, the reading control unit 103 determines the edge value in the main scanning direction and the sub value in the sub scanning direction. The edge value in the scanning direction is stored in the edge number storage unit 110 in association with each resolution.

  When the reading control unit 103 stores the number of both edges of the high-resolution (600 dpi) image data (step S112), the reading control unit 103 instructs the resolution conversion unit 111 to perform resolution conversion.

  On the other hand, when the reading control unit 103 stores the number of both edges of the image data of medium resolution (300 dpi) or low resolution (150 dpi, 75 dpi), it instructs the minimum resolution determination unit 112 to determine the minimum resolution.

  When the resolution conversion unit 111 receives an instruction for resolution conversion, if the image data stored in the image storage unit 108 is only high-resolution (600 dpi) image data, the resolution conversion unit 111 converts the high-resolution image data to medium resolution (300 dpi). ) Image data (step S113).

  On the other hand, if the lowest resolution image data among the image data stored in the image storage unit 108 is medium resolution (300 dpi) image data, the resolution conversion unit 111 reduces the medium resolution image data. The image data is converted into resolution (150 dpi) image data.

  Further, when the lowest resolution image data among the image data stored in the image storage unit 108 is low resolution (150 dpi) image data, the resolution conversion unit 111 further outputs the low resolution image data. Convert to low resolution (75 dpi) image data.

Each time the resolution conversion unit 111 generates image data of each resolution, the reading control unit 103 stores the generated image data of each resolution in the image storage unit 108.
The reading control unit 103 instructs the edge number calculation unit 109 to calculate the number of edges every time image data of each resolution converted by the resolution conversion unit 111 is stored.

Upon receiving the resolution determination instruction, the lowest resolution determination unit 112 receives the image data of the lowest resolution among the total number of edges in the main scanning direction and the total number of edges in the sub scanning direction of each resolution stored in the edge number storage unit 110. The total number of edges is compared with the total number of edges of the second lowest resolution image data (step S114), and the ratio of the total number of edges is equal to or greater than a preset threshold value (1/3 in this embodiment). Whether or not the image data with the lowest resolution can be used is determined based on whether or not (step S115).
Here, the minimum resolution determination unit 112 has a count function for counting the number of determinations, and performs determination until the number of counts reaches a preset maximum number (3 in the present embodiment).

  When the lowest resolution determination unit 112 determines that the image data with the lowest resolution stored in the edge number storage unit 110 can be used, if the determination number is not the maximum number (3 in the present embodiment) (step S116). The resolution conversion unit 111 is instructed to perform resolution conversion.

  On the other hand, if the minimum resolution determination unit 112 determines that it is usable, if the determination number is the maximum number, it determines that the lowest resolution stored in the edge number storage unit 110 is the minimum resolution (step S117). .

  If the lowest resolution determination unit 112 determines that the image data with the lowest resolution is unusable, it determines that the second lowest resolution stored in the edge number storage unit 110 is the lowest resolution (step S118). .

  When the minimum resolution determination unit 112 determines the minimum resolution, the reading control unit 103 instructs the use resolution determination unit 113 to determine the use resolution and transfers the determination result (minimum resolution).

  When the use resolution determination unit 113 receives “minimum resolution” together with an instruction to determine use resolution, the resolution conversion priority selection result (“strong”, “weak”) stored in the resolution conversion priority selection result storage unit 107. And the used resolution corresponding to the “minimum resolution” is searched from the used resolution conversion table 40 stored in the used resolution conversion table storage unit 114 to determine the used resolution (step S119). .

  When the use resolution determination unit 113 determines the use resolution, when the user selects the “copy” button (step S120), the reading control unit 103 uses the image data of the use resolution stored in the image storage unit 108 as I. The image is transferred to the image forming unit 200 via the / F unit 104. As a result, the image forming unit 200 performs print processing based on the image data of the determined use resolution (step S121). When the printing process is completed, the image forming unit 200 transmits the completion notification to the image reading unit 100. When receiving the completion notification via the I / F unit 104, the image reading unit 100 deletes the image data of each resolution based on the document stored in the image storage unit 108 from the storage unit.

  On the other hand, when the user selects the “scanner” button, the reading control unit 103 leaves only the image data of the resolution corresponding to the used resolution stored in the image storage unit 108 and the image data of other resolutions. If stored, the image data of other resolution is deleted from the storage unit (step S122). At this time, the image data of each page of the document sequentially stored in the image storage unit 108 is stored in association with each other as related data based on the control of the reading control unit 103.

<Effect of Example 1>
In the image processing apparatus 1000 according to the first embodiment, when converting (compressing) the image data to a lower resolution in order to reduce the data capacity size of the image data generated by reading the document, the image data is sequentially reduced to a predetermined lower resolution. The minimum resolution that does not deteriorate when optically reading the image written on the original is calculated based on the number of edges (contours) that characterize the image quality of each low-resolution image data, and at least the minimum resolution or higher Can be used for processing. Thus, in the image processing apparatus 1000 according to the first embodiment, particularly when a low-quality image is described, such as a document generated by copying another document or a document generated by facsimile reception, It is possible to generate appropriate low-resolution image data that can reduce image degradation as much as possible.

<Configuration of Example 2>
The image processing apparatus 1000a according to the second embodiment of the present invention replaces the configuration in which the use resolution is determined for each page of each document placed on the manual feed tray 1011 in the image processing apparatus 1000 according to the first embodiment. When the use resolution is determined for the first page, each page is optically read based on the determination result (use resolution) for the second and subsequent pages of each document, and each image of the use resolution is read. The configuration is changed to generate data.
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 15 is a block diagram illustrating a control configuration of the image processing apparatus 1000a according to the second embodiment of the present invention.
As illustrated in FIG. 15, the image processing apparatus 1000 a includes an image reading unit 100 a and an image forming unit 200.
Next, the control configuration of the image reading unit 100a will be described in detail with reference to FIG.
As shown in FIG. 14, the image reading unit 100a includes an automatic document feeding unit 101, a document reading unit 102a, a reading control unit 103a, an I / F unit 104, a user interface unit 105, and a resolution conversion priority. Selection screen storage unit 106, resolution conversion priority selection result storage unit 107, image storage unit 108, edge number calculation unit 109, edge number storage unit 110, resolution conversion unit 111, and minimum resolution determination unit 112 , A use resolution determination unit 113a, a use resolution conversion table storage unit 114, and a use resolution storage unit 115.

The used resolution storage unit 115 manually feeds the used resolution of the first page of the document placed on the manual feed tray 1011 (see FIG. 2) fed from the automatic document feeding unit 101 determined by the used resolution determination unit 113a. This is a portion to be stored for application to the resolution at the time of reading the second and subsequent pages of the document placed on the tray 1011.
The data stored in this storage unit is sequentially overwritten and erased.

When the use resolution determination unit 113a finishes determining the use resolution of the first page of the document placed on the manual feed tray 1011 (see FIG. 2), the use resolution storage unit 115 receives the determination result via the reading control unit 103a. To remember.
The use resolution determination process for the first page of each document in the use resolution determination unit 113a is the same as the use resolution determination process for the first page of each document in the use resolution determination unit 113 of the first embodiment.

When the automatic document feeder 101 feeds the second and subsequent pages of the document placed on the manual feed tray 1011, the reading control unit 103 a uses the used resolution stored in the used resolution storage unit 115 for the document reading unit 102 a. Then, control is performed to read the document and generate image data.
The reading control process for the first page of each document in the reading control unit 103a is the same as the reading control process for the first page of each document in the reading control unit 103a of the first embodiment.

The document reading unit 102a optically reads an image included in the second and subsequent pages of the document placed on the manual feed tray 1011 based on the use resolution stored in the use resolution storage unit 115, and uses the use resolution image data. Is generated.
The reading process for the first page of each document in the document reading unit 102a is the same as the reading process for the first page of each document in the document reading unit 102 of the first embodiment.

  When the document reading unit 102a generates image data of the use resolution stored in the use resolution storage unit 115 for each page after the second page of the document, the reading control unit 103a displays the case where the user selects the “copy” button. In this case, the image data of the use resolution corresponding to the second and subsequent pages of each document stored in the image storage unit 108 is transferred to the image forming unit 200 via the I / F unit 104. As a result, the image forming unit 200 performs print processing based on the image data of the use resolution corresponding to the second and subsequent pages of the document. When the image forming unit 200 completes the printing process for each page, the image forming unit 200 transmits the completion notification to the image reading unit 100a. Upon receiving the completion notification via the I / F unit 104, the image reading unit 100a deletes the image data corresponding to each page stored in the image storage unit 108 from the storage unit.

  On the other hand, when the user selects the “scanner” button, the reading control unit 103a stores one related image data of each page of the first page and the second and subsequent pages stored in the image storage unit 108. The data are sequentially stored in association with each other.

  The reading control unit 103a feeds the last page of the document placed on the manual feed tray 1011 by the automatic document feeding unit 101, and the document reading unit 102 generates image data of the use resolution corresponding to the last page. Then, the above processing is repeated until the image data is stored in the image storage unit 108 and the stored image data is output to the image forming unit 200 or held in the storage unit.

<Operation of Example 2>
FIG. 16 is a flowchart (part 1) illustrating the operation of the image processing apparatus 1000a according to the second embodiment of the present invention. FIG. 17 is a flowchart (part 2) illustrating the operation of the image processing apparatus 1000a according to the second embodiment of the present invention. FIG. 18 is a flowchart (part 3) illustrating the operation of the image processing apparatus 1000a according to the second embodiment of the present invention.
The operation of the image processing apparatus 1000a according to the second embodiment will be described in detail with reference to FIG. 16, FIG. 17, and FIG.
The operations in steps S201 to S222 in the second embodiment are the same as the operations in steps S101 to S122 in the first embodiment.

  When the use resolution determination unit 113a finishes determining the use resolution of the first page of the document placed on the manual tray fed from the automatic document feed unit 101 (step S223), the use control unit 113a reads the determination result as the read control unit. It is stored in the used resolution storage unit 115 via 103a (step S224).

  When the automatic document feeder 101 feeds the second and subsequent pages of the document placed on the manual feed tray 1011, the reading control unit 103 a uses the used resolution stored in the used resolution storage unit 115 for the document reading unit 102 a. Then, control is performed to read the document and generate image data.

  The document reading unit 102a optically reads an image included in the second and subsequent pages of the document placed on the manual feed tray 1011 based on the use resolution stored in the use resolution storage unit 115, and uses the use resolution image data. Is generated (step S225).

  When the document reading unit 102a generates image data of the use resolution stored in the use resolution storage unit 115 for each page after the second page of the document, the reading control unit 103a displays the case where the user selects the “copy” button. (Step S226), the image data of the use resolution corresponding to the second and subsequent pages of each document stored in the image storage unit 108 is transferred to the image forming unit 200 via the I / F unit 104 (Step S227). . As a result, the image forming unit 200 performs print processing based on the image data of the use resolution corresponding to the second and subsequent pages of the document. When the image forming unit 200 completes the printing process for each page, the image forming unit 200 transmits the completion notification to the image reading unit 100a. Upon receiving the completion notification via the I / F unit 104, the image reading unit 100a deletes the image data corresponding to each page stored in the image storage unit 108 from the storage unit.

  On the other hand, when the user selects the “scanner” button, the reading control unit 103a stores one related image data of each page of the first page and the second and subsequent pages stored in the image storage unit 108. The data are sequentially stored in association with each other (step S228).

  The reading control unit 103a feeds the last page of the document placed on the manual feed tray 1011 by the automatic document feeding unit 101, and the document reading unit 102 generates image data of the use resolution corresponding to the last page. The above processing is repeated until the stored image data is stored in the image storage unit 108 and the stored image data is output to the image forming unit 200 or held in the storage unit (step S229).

<Effect of Example 2>
The image processing apparatus 1000a according to the second embodiment determines the use resolution only for the first page of the document placed on the manual feed tray 1011 and stores the determination result in the use resolution storage unit 115, and then the document. When the reading unit 102 reads the second and subsequent pages of the document, each image data of the use resolution corresponding to each page is generated based on the stored use resolution. As a result, the image processing apparatus 1000a according to the second embodiment can significantly reduce the time required for reading a document composed of a plurality of pages as compared with the image processing apparatus 1000 according to the first embodiment. Can be performed smoothly.

In the above-described embodiments, the image processing apparatus of the present invention has been described as a multi-function machine having a printing function and a scanner function. However, the present invention is not limited to this, and can be applied to a multi-function machine having a facsimile function, a printer function, and the like. .
Further, the image processing apparatus of the present invention is not limited to a multifunction machine, and can be applied to an apparatus having only one function such as a printing apparatus, a scanner apparatus, and a facsimile apparatus.
Furthermore, the present invention can also be applied to determination of the compression rate for irreversible image compression (JPEG, PNG, PDF, GIF).

1000 Image Processing Device 100 Image Reading Unit 101 Automatic Document Feeding Unit 1011 Manual Tray 102 Document Reading Unit 103 Reading Control Unit 104 I / F Unit 105 User Interface Unit 106 Resolution Conversion Priority Selection Screen Storage Unit 107 Resolution Conversion Priority Selection Result Storage unit 108 Image storage unit 109 Edge number calculation unit 110 Edge number storage unit 111 Resolution conversion unit 112 Minimum resolution determination unit 113 Use resolution determination unit 114 Use resolution conversion table storage unit 115 Use resolution storage unit 200 Image formation unit

Claims (3)

An image processing apparatus including an original reading unit that reads original image information described in an original with a predetermined resolution to generate image data,
A resolution converter that converts the generated image data into low-resolution image data lower than the resolution of the image data;
An edge number calculation unit that extracts each edge portion included in each image data from the generated image data and the converted low-resolution image data, and calculates each total number of edge portions included in each image data When,
The total number of edges of the generated image data calculated by the edge number calculation unit is compared with the total number of edges of the converted low-resolution image data , and whether or not the ratio of the total number of both edges is equal to or less than a preset threshold value. A minimum resolution determination unit that determines whether or not the converted low-resolution image data can be used,
When the lowest resolution determination unit determines that it is unusable, the generated image data is determined to be the lowest resolution image data, and an output unit that outputs the image data;
A controller that controls the resolution conversion unit to convert the converted low-resolution image data into lower-resolution image data when the minimum resolution determination unit determines that it can be used;
Each time the minimum resolution determination unit determines that the minimum resolution determination unit is usable, the control unit converts the low resolution image data sequentially converted to the resolution conversion unit into lower resolution image data, and causes the edge number calculation unit to the total number of edges of the low-resolution image data obtained by sequentially converting the by comparing the total number of edges images data converted to a lower resolution than the image data converted from the low resolution said that whether it is possible to use An image processing apparatus that is controlled to make a determination.   The document reading unit includes an automatic document feeding unit capable of sequentially feeding a document composed of a plurality of pages. When reading each page of the document fed to the automatic document feeding unit, the document reading unit 2. The image according to claim 1, wherein the original image information described in the second and subsequent pages of the document is read based on the minimum resolution determined by the minimum resolution determination unit for the first page. Processing equipment.   The edge number calculating unit determines each edge included in a certain range moved from a predetermined region from the point where the edge is first determined in the image data of each resolution, and calculates the total number of edges. The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus.

Images