JP2015226184A - Image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently utilize a storage unit for temporarily storing data read out from a page memory.SOLUTION: A block 31 has a structure that segments 34 each comprising pixels 33 continuously arrayed in a main scanning direction D1 are continuously arrayed in a sub-scanning direction D2. A reading unit 16 reads out segment data to be data including the segment 34 as a unit from a page memory 11 and temporarily stores the segment data in a segment memory 13. A setting unit 17 sets the number of pixels of each segment 34 so that when a bpp value of an image 30 of one page is reduced, the number of pixels is increased, and when the bpp value of the image 30 of one page is increased, the number of pixels is reduced. A division unit 15 divides the image 30 of one page to a plurality of blocks 31 each of which is constituted of segments 34 each having the set number of pixels.

Description

  The present invention relates to a technique for reading image data stored in a page memory and performing predetermined image processing.

  An image processing apparatus mounted on an image forming apparatus such as a multifunction machine performs image processing using a page memory. More specifically, the page memory stores image data indicating an image of one page. An image of one page has a structure in which lines composed of pixels continuously arranged in the main scanning direction are arranged in succession in the sub-scanning direction. The image processing apparatus reads the image data stored in the page memory in units of line data, temporarily stores the read line data in a storage unit (for example, line memory) serving as a buffer, and temporarily stores the data in the storage unit The line data thus read is read out and subjected to predetermined image processing.

  An image processing apparatus that divides an image of one page into a plurality of blocks and performs image processing in units of blocks has been proposed (for example, see Patent Document 1). According to this, since image processing is performed in units of blocks, the segment data is read from the page memory in units of block line data called segment data instead of image line data, and the segment data is temporarily stored in the storage unit. Remembered. Since the segment data has a data amount smaller than that of the line data, the capacity of the storage unit can be reduced.

JP 2010-87804 A

  In order to reduce the cost of the multifunction peripheral, image processing may be executed by the same image processing apparatus even for jobs having different functions (for example, a scanner function and a facsimile function). In this case, for example, a job with a large bpp value is used for a job having a different number of bits per pixel (bpp), such as a 24 bpp color scan and a 1 bpp facsimile. For a job with a small bpp value, a configuration in which only a part of the storage unit is used is not preferable in terms of efficient use of the storage unit.

  It is an object of the present invention to provide an image processing apparatus that can efficiently use a storage unit that temporarily stores data read from a page memory.

  An image processing apparatus according to the present invention that achieves the above object includes a page memory that stores image data indicating an image of one page, a dividing unit that divides the image of one page into a plurality of blocks, and the block includes: In order to perform a predetermined image processing of the image of the one page in units of the block, it has a structure in which segments composed of pixels continuously arranged in the main scanning direction are arranged in the sub scanning direction. A reading unit that reads out the image data from the page memory in units of segment data that is data indicating the segment, a storage unit that temporarily stores the segment data read by the reading unit, and a storage unit An image processing unit that performs the predetermined image processing using the stored segment data, and a 1-page image (bpp) (bits per pixel) A setting unit configured to set the number of pixels of the segment so that the number of pixels is increased when the Bpp value of the image of one page is increased. Divides the image of one page into the plurality of blocks configured by the segments having the number of pixels set by the setting unit.

  According to the aspect in which the number of pixels in the segment is the same regardless of the bpp value (the number of bits of one pixel), a job having a large bpp value has a larger amount of segment data than a job having a small bpp value. Accordingly, the entire storage unit can be used for a job having a large bpp value, but only a part of the storage unit can be used for a job having a small bpp value.

  According to the image processing apparatus of the present invention, the setting unit increases the number of pixels when the bpp value of the image of one page decreases, and decreases the number of pixels when the bpp value of the image of one page increases. Thus, the number of pixels in the segment is set. Thereby, the difference of the data amount of the segment data according to the bpp value of the image of one page can be made small or the same. Accordingly, since only a part of the storage unit can be prevented from being used for the storage unit that temporarily stores the data (segment data) read from the page memory, the storage unit can be used efficiently.

  In the above configuration, the setting unit sets the number of pixels so that the data amount of the segment is the same regardless of the bpp value of the image of the one page.

  In the above configuration, the setting unit sets the number of pixels in the segment to n when the bpp value is 1 and the number of pixels in the main scanning direction is n in the image of one page.

  As the number of blocks increases, the image processing speed decreases. In this configuration, when the bpp value is 1, the segment can be matched with the line, so that one page image is not divided in the main scanning direction. Therefore, according to this configuration, the number of blocks can be minimized.

  In the above-described configuration, the setting unit is configured such that, in the one-page image, when the bpp value is m (m is an integer greater than 1) and the number of pixels in the main scanning direction is n, the pixels of the segment The number is set to n / m.

  According to this configuration, the data amount of the segment data can be made the same as in the case where the bpp value is 1 and the number of pixels in the main scanning direction is n in one page image.

  According to the present invention, a storage unit that temporarily stores data read from a page memory can be used efficiently.

1 is a schematic diagram illustrating an outline of an internal structure of an image forming apparatus equipped with an image processing apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus illustrated in FIG. 1. It is a block diagram which shows the structure of the image processing apparatus which concerns on this embodiment. It is a schematic diagram which shows the image of 1 page divided | segmented into the several block. It is a schematic diagram which shows the 1st example of the image of 1 page divided | segmented into the some block. It is a schematic diagram which shows the 2nd example of the image of 1 page divided | segmented into the some block. FIG. 6 is an explanatory diagram for explaining segment data stored in a segment memory in the case of an image of one page shown in FIG. 5. FIG. 7 is an explanatory diagram for explaining segment data stored in a segment memory in the case of an image of one page shown in FIG. 6.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an outline of the internal structure of an image forming apparatus 1 equipped with an image processing apparatus 10 (FIG. 3) according to an embodiment of the present invention. The image forming apparatus 1 can be applied to, for example, a digital multifunction machine having functions of a copy, a printer, a scanner, and a facsimile. The image forming apparatus 1 is arranged on the apparatus main body 100, a document reading unit 200 disposed on the apparatus main body 100, a document feeding unit 300 disposed on the document reading unit 200, and an upper front surface of the apparatus main body 100. The operation unit 400 is provided.

  The document feeding unit 300 functions as an automatic document feeding device, and can feed a plurality of documents placed on the document placing unit 301 so that the document reading unit 200 can read them continuously.

  The document reading unit 200 includes a carriage 201 on which an exposure lamp or the like is mounted, a document table 203 made of a transparent member such as glass, a CCD (Charge Coupled Device) sensor (not shown), and a document reading slit 205. When reading a document placed on the document table 203, the document is read by the CCD sensor while moving the carriage 201 in the longitudinal direction of the document table 203. On the other hand, when reading a document fed from the document feeding unit 300, the carriage 201 is moved to a position facing the document reading slit 205, and the document fed from the document feeding unit 300 is scanned. Reading is performed by the CCD sensor through the reading slit 205. The CCD sensor outputs the read original as image data.

  The apparatus main body 100 includes a sheet storage unit 101, an image forming unit 103, and a fixing unit 105. The sheet storage unit 101 is disposed at the lowermost part of the apparatus main body 100 and includes a sheet tray 107 that can store a bundle of sheets. In the bundle of sheets stored in the sheet tray 107, the uppermost sheet is sent out toward the sheet conveyance path 111 by driving the pickup roller 109. The sheet is conveyed to the image forming unit 103 through the sheet conveyance path 111.

  The image forming unit 103 forms a toner image on the conveyed paper. The image forming unit 103 includes a photosensitive drum 113, an exposure unit 115, a developing unit 117, and a transfer unit 119. The exposure unit 115 generates light modulated in accordance with image data (image data output from the document reading unit 200, image data transmitted from a personal computer, image data received by facsimile, etc.), and is uniformly charged. Irradiate to the peripheral surface of the photosensitive drum 113. As a result, an electrostatic latent image corresponding to the image data is formed on the peripheral surface of the photosensitive drum 113. In this state, toner is supplied to the peripheral surface of the photosensitive drum 113 from the developing unit 117, so that a toner image corresponding to the image data is formed on the peripheral surface. This toner image is transferred by the transfer unit 119 to the sheet conveyed from the sheet storage unit 101 described above.

  The sheet on which the toner image is transferred is sent to the fixing unit 105. In the fixing unit 105, heat and pressure are applied to the toner image and the paper, and the toner image is fixed to the paper. The paper is discharged to the stack tray 121 or the paper discharge tray 123.

  The operation unit 400 includes an operation key unit 401 and a display unit 403. The display unit 403 has a touch panel function, and displays a screen including soft keys. The user operates the soft key while viewing the screen to make settings necessary for executing functions such as copying.

  The operation key unit 401 is provided with operation keys including hard keys. Specifically, a start key 405, a numeric keypad 407, a stop key 409, a reset key 411, a function switching key 413 for switching between copy, printer, scanner, and facsimile are provided.

  A start key 405 is a key for starting operations such as copying and facsimile transmission. A numeric keypad 407 is a key for inputting numbers such as the number of copies and a facsimile number. A stop key 409 is a key for stopping a copy operation or the like halfway. The reset key 411 is a key for returning the set contents to the initial setting state.

  The function switching key 413 includes a copy key, a transmission key, and the like, and is a key for switching between a copy function, a transmission function, and the like. When the copy key is operated, an initial copy screen is displayed on the display unit 403. When the transmission key is operated, an initial screen for facsimile transmission and mail transmission is displayed on the display unit 403.

  FIG. 2 is a block diagram showing a configuration of the image forming apparatus 1 shown in FIG. The image forming apparatus 1 has a configuration in which an apparatus main body 100, a document reading unit 200, a document feeding unit 300, an operation unit 400, a control unit 500, and a communication unit 600 are connected to each other by a bus. Since the apparatus main body 100, the document reading unit 200, the document feeding unit 300, and the operation unit 400 have already been described, description thereof is omitted.

  The control unit 500 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an image memory, and the like. The CPU executes control necessary for operating the image forming apparatus 1 for the above-described components of the image forming apparatus 1 such as the apparatus main body 100. The ROM stores software necessary for controlling the operation of the image forming apparatus 1. The RAM is used for temporary storage of data generated during execution of software, storage of application software, and the like. The image memory temporarily stores image data (image data output from the document reading unit 200, image data transmitted from a personal computer, image data received by facsimile, etc.).

  The control unit 500 has a function as the image processing apparatus 10 as one of the functions. Details of the image processing apparatus 10 will be described later.

  The communication unit 600 includes a facsimile communication unit 601 and a network I / F unit 603. The facsimile communication unit 601 includes an NCU (Network Control Unit) that controls connection of a telephone line with a destination facsimile, and a modulation / demodulation circuit that modulates / demodulates a signal for facsimile communication. The facsimile communication unit 601 is connected to the telephone line 605.

  The network I / F unit 603 is connected to a LAN (Local Area Network) 607. A network I / F unit 603 is a communication interface circuit for executing communication with a terminal device such as a personal computer connected to the LAN 607.

  FIG. 3 is a block diagram illustrating a configuration of the image processing apparatus 10 according to the present embodiment. The image processing apparatus 10 includes a page memory 11, a memory control unit 12, a segment memory 13, and an image processing unit 14.

  The page memory 11 is, for example, a DRAM (Dynamic Random Access Memory), and stores image data indicating an image of one page.

  The memory control unit 12 is an LSI (Large Scale Integration) that performs control for reading data stored in the page memory 11 and sending the data to the image processing unit 14. The memory control unit 12 includes a dividing unit 15, a reading unit 16, a setting unit 17, and a line restoration unit 18.

  The dividing unit 15 divides an image of one page into a plurality of blocks. FIG. 4 is a schematic diagram showing one page of image 30 divided into a plurality of blocks 31 by the dividing unit 15. The image 30 of one page is divided into P equal parts in the main scanning direction D1, and divided into Q equal parts in the sub-scanning direction D2, thereby being divided into P × Q blocks 31. In the image 30 of one page, the number of pixels in the main scanning direction D1 is the number of pixels in the main scanning direction D1 of the block 31 × P, and the number of pixels in the sub-scanning direction D2 is the number of pixels in the sub-scanning direction D2 of the block 31. × Q. In fact, as will be described later, in the image processing by the filter operation, it is necessary to refer to the image data of the adjacent block, so that the boundary of the block is divided so as to overlap like a margin.

  The image 30 of one page has a structure in which lines 32 constituted by pixels 33 continuously arranged in the main scanning direction D1 are continuously arranged in the sub-scanning direction D2. The block 31 has a structure in which the segments 34 are continuously arranged in the sub-scanning direction D2. The segment 34 is composed of pixels 33 that are continuously arranged in the main scanning direction D1. The number of pixels 33 constituting the segment 34 is the number of pixels in the main scanning direction D1 of the block 31. In the image 30 of one page, if P segments 34 are connected in the main scanning direction D1, a line 32 is obtained.

  Referring to FIG. 3, reading unit 16 performs image processing from page memory 11 in units of segment data, which is data indicating segment 34, in order to perform predetermined image processing on image 30 of one page in units of blocks 31. Data is read, and the read segment data is transferred to the image processing unit 14. The segment data is data indicating a portion indicated by the segment 34 in the image 30 of one page.

  The setting unit 17 and the line restoration unit 18 will be described later.

  The segment memory 13 is a memory that becomes a buffer when the segment data read by the reading unit 16 is transferred to the image processing unit 14. The segment memory 13 is, for example, an SRAM (Static Random Access Memory). The segment memory 13 is an example of a storage unit. The storage unit temporarily stores the segment data read by the reading unit 16.

  The two segment memories 13 are provided because the image processing unit 14 performs 3 × 3 filter processing as predetermined image processing. The number of segment memories 13 is one or more, and the number of segment memories 13 is determined according to image processing executed by the image processing unit 14. If it is not necessary to distinguish between the two segment memories 13a and 13b, they are referred to as segment memory 13.

  The image processing unit 14 performs predetermined image processing using the segment data stored in the segment memory 13. In the present embodiment, as described above, the image processing unit 14 performs 3 × 3 filter processing on image data indicating an image of one page stored in the page memory 11. The predetermined image processing is not limited to 3 × 3 filter processing.

  The image processing unit 14 performs 3 × 3 filter processing on the P × N blocks 31 in order from the first block 31. The segment memory 13b stores the segment data read by the reading unit 16 last time, and the segment memory 13a stores the segment data previously read by the reading unit 16. Therefore, when the reading unit 16 reads the segment data, the segment data read this time, the previously read segment data stored in the segment memory 13a, and the previous read stored in the segment memory 13b are read. 3 × 3 filter processing is performed using the segmented data.

  The line restoration unit 18 will be described. The line restoration unit 18 connects the segment data subjected to the 3 × 3 filter processing by the image processing unit 14 to restore the line data, and stores the line data in the page memory 11.

  The setting unit 17 increases the number of pixels when the bpp (bits per pixel) value of the image 30 of one page shown in FIG. 4 decreases, and decreases the number of pixels when the bpp value of the image 30 of one page increases. Thus, the number of pixels of the segment 34 is set within a range that does not exceed the amount of data that can be stored in each segment memory 13. The dividing unit 15 divides the image 30 of one page into a plurality of blocks 31 including the segments 34 having the number of pixels set by the setting unit 17.

  FIG. 5 is a schematic diagram showing a first example of a one-page image 30 a divided into a plurality of blocks 31 by the dividing unit 15. The one-page image 30a is an image indicated by image data stored in the page memory 11 when the image forming apparatus 1 executes a 24 bpp color scan job. The bpp value of the pixels 33 constituting the image 30a for one page is 24.

  The image 30a of one page is divided into 24 along the main scanning direction D1, for example, and divided into Q (Q is an integer of 2 or more) along the sub scanning direction D2, thereby 24 × Q blocks. It is divided into 31. Hereinafter, in order to help understanding of the present embodiment, the number of divisions and the number of pixels are specifically shown in the main scanning direction D1. These numbers are specific examples and are not limited to these numbers.

  If the number of pixels in the main scanning direction D1 of one page image 30a is, for example, 2400, the one page image 30a is divided into 24 in the main scanning direction D1, so the number of pixels in the main scanning direction D1 of the block 31 Becomes 100.

  A line of the image 30a of one page is composed of 2400 pixels 33 arranged continuously in the main scanning direction D1. The segment 34 is composed of 100 pixels 33 arranged continuously in the main scanning direction D1. In the image 30a of one page, if 24 segments 34 are connected in the main scanning direction D1, a line is formed.

  FIG. 6 is a schematic diagram illustrating a second example of a one-page image 30 b that has been divided into a plurality of blocks 31 by the dividing unit 15. If it is not necessary to distinguish the one-page images 30a and 30b, they are referred to as one-page images 30.

  The one-page image 30b is an image indicated by image data stored in the page memory 11 when the image forming apparatus 1 executes a 1 bpp factory job. The bpp value of the pixels 33 constituting the image 30b of one page is 1.

  The image 30b for one page is not divided along the main scanning direction D1, but is divided into Q blocks 31 by Q division along the sub scanning direction D2.

  If the number of pixels in the main scanning direction D1 of the image 30b for one page is 2400, the segment 34 of the image 30b for one page is composed of 2400 pixels 33 arranged continuously in the main scanning direction D1. Therefore, in one page image 30b, the segment 34 matches the line.

  As described above, with reference to FIG. 5 and FIG. 6, the dividing unit 15 determines that the image 30 of one page has the number of pixels in the main scanning direction D1 equal to or less than the number of pixels in the main scanning direction D1 of the image 30 of one page. Is divided into a plurality of blocks 31. In other words, the dividing unit 15 divides the image 30 of one page into a plurality of blocks 31 in which the number of pixels in the main scanning direction D1 is variable.

  FIG. 7 is an explanatory diagram for explaining segment data stored in the segment memory 13 in the case of the one-page image 30a shown in FIG. FIG. 8 is an explanatory diagram for explaining segment data stored in the segment memory 13 in the case of the image 30b for one page shown in FIG. In any image 30, the segment data stored in the segment memory 13 has the same data amount (2400 bits).

  The main effects of this embodiment will be described. According to the aspect in which the number of pixels of the segment 34 is the same regardless of the bpp value (the number of bits of one pixel 33), a job with a large bpp value has a larger amount of segment data than a job with a small bpp value. Become. Accordingly, the entire segment memory 13 can be used for a job having a large bpp value, but only a part of the segment memory 13 can be used for a job having a small bpp value.

  According to the image processing apparatus 10 according to the present embodiment, the setting unit 17 increases the number of pixels when the bpp value of the image 30 on one page decreases, and increases the bpp value of the image 30 on one page. The number of pixels in the segment 34 is set so that the number of pixels is small. Thereby, the difference of the data amount of the segment data according to the bpp value of the image of one page can be made small or the same. Accordingly, since only a part of the segment memory 13 can be prevented from being used for the segment memory 13 that temporarily stores the segment data read from the page memory 11, the segment memory 13 can be used efficiently.

  When one page of image 30 is subjected to image processing in units of blocks 31, image processing of one page of image 30 is delayed as the number of blocks 31 increases. As shown in FIG. 4, for the pixel 33-1 located at the boundary of the block 31, the segment data of the two blocks 31 adjacent in the main scanning direction D1 as in the margin allowance is used for image processing. Because it is done. According to the present embodiment, the setting unit 17 sets the number of pixels of the segment 34 so that the number of pixels increases as the bpp value of the image 30 of one page decreases. For this reason, in the case of a job having a small bpp value, the number of blocks 31 can be reduced, so that the image processing of the image 30 of one page can be accelerated.

  As described with reference to FIGS. 7 and 8, according to the present embodiment, the setting unit 17 sets the number of pixels so that the segment data amount is the same regardless of the bpp value of the image 30 of one page. To do. For this reason, since the data amount of the segment data can be made the same regardless of the bpp value of the image 30 of one page, the control of the segment memory 13 by the memory control unit 12 becomes simple.

  As described with reference to FIG. 6, the setting unit 17 sets the segment 34 when the bpp value is 1 and the number of pixels in the main scanning direction D1 is n (here, 2400) in the image 30b of one page. The number of pixels is set to n (2400). As described above, when the number of blocks 31 increases, the image processing speed of the image 30 of one page decreases. In the present embodiment, when the bpp value is 1, the segment 34 can be matched with the line, so the image 30b of one page is not divided in the main scanning direction D1. Therefore, the number of blocks 31 can be minimized.

  As described with reference to FIG. 5, in the image 30a of one page, the setting unit 17 has a bpp value of m (m is an integer larger than 1, here, 24), and the number of pixels in the main scanning direction D1 is In the case of n (here, 2400), the number of pixels of the segment 34 is set to n / m. Therefore, as described with reference to FIGS. 7 and 8, the data amount of the segment data can be the same in the image 30a of one page and the image 30b of one page (FIG. 6).

DESCRIPTION OF SYMBOLS 10 Image processing apparatus 30,30a, 30b Image of 1 page 31 Block 33 Pixel 34 Segment D1 Main scanning direction D2 Sub scanning direction

Claims (4)

A page memory in which image data representing an image of one page is stored;
A dividing unit for dividing the image of one page into a plurality of blocks;
The block has a structure in which segments composed of pixels continuously arranged in the main scanning direction are continuously arranged in the sub-scanning direction, and the image of the one page is subjected to predetermined image processing in units of the block. In order to do so, a reading unit that reads out the image data from the page memory in units of segment data that is data indicating the segment;
A storage unit for temporarily storing the segment data read by the reading unit;
An image processing unit that performs the predetermined image processing using the segment data stored in the storage unit;
The number of pixels in the segment so that the number of pixels increases as the bpp (bits per pixel) value of the image of one page decreases, and the number of pixels decreases as the bpp value of the image of one page increases. A setting unit for setting
The image processing apparatus that divides the image of one page into the plurality of blocks configured by the segments having the number of pixels set by the setting unit.   The image processing apparatus according to claim 1, wherein the setting unit sets the number of pixels so that the data amount of the segment is the same regardless of a bpp value of the image of the one page.   The setting unit sets the number of pixels of the segment to the n when the bpp value is 1 and the number of pixels in the main scanning direction is n in the image of the one page. The image processing apparatus described.   In the one-page image, when the bpp value is m (m is an integer greater than 1) and the number of pixels in the main scanning direction is the n, the setting unit determines the number of pixels in the segment. The image processing apparatus according to claim 3, wherein n / m is set.

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