JP2011049893A - Image processor and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To process image data obtained by color scanning, for every block by less memory access using a small-sized buffer memory. <P>SOLUTION: A raster writing part 12 sequentially writes pieces of line data in a plurality of colors in the buffer memory 3 along the vertical scanning direction by shifting addresses for offset corresponding to intervals of line sensors 1R, 1G, 1B, respectively. Then, a block reading part 13 reads pieces of block data 31R, 31G, 31B from a plurality of pieces of line data for the respective colors written in the buffer memory 3, and a block image processing part 14 performs predetermined data processing to the pieces of block data 31R, 31G, 31B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image forming apparatus.

  In order to reduce the size of the line memory, a technique for dividing an image into a plurality of blocks and performing image processing for each block has been proposed (for example, see Patent Document 1). According to this technique, the size of the line memory can be reduced by the length of the block in the main scanning direction.

  In addition, in a certain image processing apparatus, in order to match the reading position of each RGB sensor chip in the scanning direction, the line data obtained by scanning is delayed using a field memory according to the scanning speed in the sub-scanning direction. The technique to make is proposed (for example, refer patent document 2).

JP-A-2005-198121 Japanese Patent Laid-Open No. 9-261491

  In an image forming apparatus, a document is scanned in color, and image processing may be performed for each block using image data obtained by scanning. For example, in the case of copy processing, data processing is performed for each block on image data obtained by document scanning, and a copy of the document is printed using the image data after data processing.

  Since the image forming apparatus uses a line scanner, the image data is generated in line units as line data. In such a case, since the line scanner uses a plurality of line sensors corresponding to a plurality of colors, a plurality of colors are used while buffering the line data using a field memory in accordance with the deviation of the reading position of the line sensor. Synchronize the line data. When this image data is subjected to data processing for each block, for each color, the number of line data equal to or greater than the length of the block in the sub-scanning direction is stored in the buffer memory, and the image data is stored for each block from the buffer memory. (That is, block data) is read and data processing is performed on the block data.

  As described above, since image data is buffered at the time of line correction and block conversion, the required memory size is increased, memory access is increased, and a series of image processing is delayed.

  The present invention has been made in view of the above problems, and an image processing apparatus capable of processing image data obtained by color scanning on a block-by-block basis with a small memory access using a small size buffer memory. An object is to obtain an image forming apparatus.

  In order to solve the above problems, the present invention is configured as follows.

One of the image processing apparatuses according to the present invention sub-scans the buffer memory by shifting the address of the line data of multiple colors by the line sensors of the multiple colors in the line scanner by an offset corresponding to the interval of the line sensors. A raster writing unit that writes data sequentially in the direction, a block reading unit that reads block data from a plurality of line data for each color written to the buffer memory, and a predetermined block data read by the block reading unit A block image processing unit for performing the data processing.
Is.

  As a result, line correction and block conversion are performed by one write and one read to the buffer memory, so that only one buffer memory is required and memory access to the buffer memory is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory.

  In addition to the image processing apparatus described above, the image processing apparatus according to the present invention may be configured as follows. In this case, the image processing apparatus further includes an interline correction address calculation unit that calculates an address shifted by an offset corresponding to the interval between the line sensors. Then, the raster writing unit writes the line data at the address calculated by the interline correction address calculation unit.

  Accordingly, even when various settings such as the scan speed are changed, the write address can be accurately specified by the inter-line correction address calculation unit.

  Also, one of the image processing apparatuses according to the present invention includes a raster writing unit for sequentially writing line data of a plurality of colors by a line sensor of a plurality of colors in a line scanner to a buffer memory in the sub-scanning direction, and a line A block reading unit that reads block data from a plurality of line data for each color written in the buffer memory while shifting an address by an offset corresponding to the sensor interval, and block data read by the block reading unit And a block image processing unit for performing predetermined data processing.

  As a result, line correction and block conversion are performed by one write and one read to the buffer memory, so that only one buffer memory is required and memory access to the buffer memory is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory.

  In addition to the image processing apparatus described above, the image processing apparatus according to the present invention may be configured as follows. In this case, the image processing apparatus further includes an interline correction address calculation unit that calculates an address shifted by an offset corresponding to the interval between the line sensors. The block reading unit reads block data from the address calculated by the interline correction address calculation unit.

  Thereby, even when various settings such as the scan speed are changed, the read address can be accurately specified by the inter-line correction address calculation unit.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the raster writing unit sequentially writes line data of a color corresponding to the buffer area to each of the plurality of buffer areas in the buffer memory.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the block image processing unit compresses the block data using the JPEG method.

  An image forming apparatus according to the present invention includes a line scanner that outputs line data of a plurality of colors by a line sensor of a plurality of colors, a buffer memory, and addresses of the line data of a plurality of colors by an offset corresponding to the interval between the line sensors. A raster writing unit that sequentially writes data in the buffer memory along the sub-scanning direction, a block reading unit that reads block data from a plurality of line data for each color written in the buffer memory, and a block reading unit A block image processing unit that performs predetermined data processing on the read block data.

  As a result, line correction and block conversion are performed by one write and one read to the buffer memory, so that only one buffer memory is required and memory access to the buffer memory is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory.

  The image forming apparatus according to the present invention includes a line scanner that outputs line data of a plurality of colors by a line sensor of a plurality of colors, a buffer memory, and each of the line data of a plurality of colors in the buffer memory along the sub-scanning direction. A raster writing unit for writing sequentially, a block reading unit for reading block data from a plurality of line data for each color written in the buffer memory while shifting an address by an offset corresponding to the interval between line sensors, and block reading A block image processing unit that performs predetermined data processing on the block data read by the unit.

  As a result, line correction and block conversion are performed by one write and one read to the buffer memory, so that only one buffer memory is required and memory access to the buffer memory is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory.

  According to the present invention, it is possible to obtain an image processing apparatus and an image forming apparatus capable of processing image data obtained by color scanning for each block with a small memory access using a small size buffer memory.

FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a diagram for explaining an offset of line data resulting from a difference in the installation position (reading position) of the line sensor in FIG. FIG. 3 is a diagram for explaining reading of block data by the block reading unit in FIG. FIG. 4 is a block diagram showing the configuration of the image forming apparatus according to Embodiment 2 of the present invention. FIG. 5 is a diagram for explaining reading of block data by the block reading unit in FIG.

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

Embodiment 1 FIG.

  FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to Embodiment 1 of the present invention. In the first embodiment, the image forming apparatus is a multifunction machine. As shown in FIG. 1, the image forming apparatus includes a line scanner 1, an image processing device 2, a buffer memory 3, a printing device 4, a communication device 5, and a storage device 6.

  The line scanner 1 includes line sensors 1R, 1G, and 1B of a plurality of colors (R (red), G (green), and B (blue)). The line sensors 1R, 1G, and 1B have optical sensor elements such as a CCD (Charge Coupled Device). The line sensors 1R, 1G, and 1B each read a document line by line along the main scanning direction, and the line scanner 1 outputs line data of one line of each color read by the line sensors 1R, 1G, and 1B. . Here, the line data is raster data having a height of one pixel and a width of a predetermined number of pixels. A drive system (not shown) moves the line sensors 1R, 1G, and 1B or the original along the sub-scanning direction so that the line sensors 1R, 1G, and 1B read an image on the original surface, and the line scanner 1 uses the line sensor 1R. , 1G, 1B, the line data of one line of each color is output in order along the sub-scanning direction.

  These line sensors 1R, 1G, and 1B are arranged at predetermined intervals in the sub-scanning direction. Therefore, a certain position of the document is read by the line sensors 1R, 1G, and 1B at different timings. Accordingly, in order to synchronize the RGB image data, inter-line correction is performed as described later.

  In addition, the image processing apparatus 2 uses a single buffer memory 3 to perform inter-line correction and block conversion, and performs data processing on image data for each block. The image processing apparatus 2 includes an application specific integrated circuit (ASIC) and / or a computer (that is, a processor such as a CPU (Central Processing Unit) that executes a program), and realizes each arithmetic processing unit. In the first embodiment, the image processing apparatus 2 includes an interline correction address calculation unit 11, a raster writing unit 12, a block reading unit 13, and a block image processing unit 14.

  The inter-line correction address calculation unit 11 is an arithmetic processing unit that calculates an address shifted by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B. The offset amount of this address is calculated based on the scanning speed in the sub-scanning direction and the number of lines (offset line number) obtained from the intervals between the line sensors 1R, 1G, 1B.

  For example, when the line sensor 1R, the line sensor 1G, and the line sensor 1B are arranged in this order in the scanning direction, the offset between the line sensor 1R and the line sensor 1B (that is, the R line data and the B line) Offset between the data) and the offset between the line sensor 1G and the line sensor 1B (that is, the offset between the G line data and the B line data). FIG. 2 is a diagram for explaining line data offset due to a difference in installation positions (reading positions) of the line sensors 1R, 1G, and 1B in FIG.

  The raster writing unit 12 shifts the address of the line data of the plurality of colors by the line sensors 1R, 1G, and 1B in the line scanner 1 by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B, respectively. An arithmetic processing unit that writes data in the buffer memory 3 in order along the sub-scanning direction. In the first embodiment, the raster writing unit 12 writes line data to the address calculated by the interline correction address calculation unit 11. In the first embodiment, the raster writing unit 12 sequentially writes the line data of the color corresponding to the buffer area to each of the plurality of buffer areas in the buffer memory 3.

  The block reading unit 13 is an arithmetic processing unit that reads block data (that is, block data for each color of RGB at the same position in the document image) from a plurality of line data for each color written in the buffer memory 3.

  The block image processing unit 14 is an arithmetic processing unit that performs predetermined data processing on the block data read by the block reading unit 13. In the first embodiment, the block image processing unit 14 compresses block data by the JPEG method, for example.

  In addition to these, the image processing device 2 is processed by the block image processing unit 14 and an arithmetic processing unit that converts data processed by the block image processing unit 14 into control data for the printing device 4. And an arithmetic processing unit that converts the data into a file of a predetermined file format for transmission by the communication device 5 or storage in the storage device 6.

  The buffer memory 3 is a memory that temporarily stores line data output from the line scanner 1. For example, an SRAM (Static Random Access Memory) is used as the buffer memory 3. The buffer memory 3 may be configured by all the memory areas of one memory element, or may be configured by a partial memory area of one memory element.

  The printing apparatus 4 is an apparatus that operates according to control data from the image processing apparatus 2 and prints an image on a print sheet according to the control data. The communication device 5 is a device that transmits image data processed by the image processing device 2 and a file including the image data. For example, a modem or a network interface is used as the communication device 5. The storage device 6 is a device that stores the image data processed by the image processing device 2 as a file. As the storage device 6, for example, a hard disk drive, a non-volatile memory (for example, a flash memory), or the like is used.

  Next, the operation of the above apparatus will be described.

  The line scanner 1 outputs RGB line data obtained at each time point by the line sensors 1R, 1G, and 1B. That is, the i-th line data for each of RGB has pixel values based on sensor detection values obtained at the same time. For this reason, RGB line data output at a certain point in time has pixel values based on sensor detection values for lines at different positions in the document image.

  In the image processing apparatus 2, the inter-line correction address calculation unit 11 calculates the address of the buffer memory 3 to which the RGB line data is written. When the line sensors 1R, 1G, and 1B are arranged in the order of RGB in the scan direction, the leading addresses Xr, Xg, and Xb of the area in which the i-th line data is written for each color of RGB are calculated as follows. The start address of the buffer area for each RGB color is Xr0, Xg0, Xb0, the size of one line data is L, the number of offset lines between the line sensor 1R and the line sensor 1B is N1, and the line sensor 1G and the line If the number of offset lines with the sensor 1B is N2, the addresses Xr, Xg, and Xb are calculated by the following equations.

Xr = Xr0 + (i−1) × L
Xg = Xg0 + (i-1 + N2-N1) * L
Xb = Xb0 + (i-1-N1) × L

  The raster writing unit 12 writes line data from the addresses calculated by the inter-line correction address calculation unit 11 for each of RGB. For B, the raster writing unit 12 does not write the first to N1th line data not including the document image. For G, the raster writing unit 12 does not write the first to (N1-N2) -th line data that does not include the document image. Note that (N1-N2) is the number of offset lines between the line sensor 1R and the line sensor 1G.

  By doing so, line-to-line correction is performed when writing to the buffer memory 3.

  Thereafter, the block reading unit 13 sequentially reads the image data including line data from the buffer memory 3 as block data having a predetermined shape. FIG. 3 is a diagram for explaining reading of block data by the block reading unit 13 in FIG. The block data pixel group has a quadrangular shape extending over a plurality of lines. In FIG. 3, as an example, the shape of the pixel group of the block data is a square of 8 pixels vertically and horizontally.

  The block reading unit 13 reads the block data 31R, 31G, 31B read j-th (j = 1, 2, 3,...) From the leading addresses of the RGB buffer areas 21R, 21G, 21B, the shape of the block data, and the like. The address of the pixel belonging to is specified, and block data 31R, 31G, and 31B are read out. In the first embodiment, the relative addresses of the block data 31R, 31G, and 31B from the heads of the buffer areas 21R, 21G, and 21B have the same value. The block image processing unit 14 performs predetermined processing (for example, JPEG compression) on the block data 31R, 31G, and 31B.

  Depending on the type of processing in the block image processing unit 14, pixels belonging to the jth block data 31R, 31G, 31B and pixels belonging to the previous and / or subsequent block data 31R, 31G, 31B are included. The block data 31R, 31G, 31B may be read so as to overlap, or the block data 31R, 31G, 31B may be read so as not to overlap.

  Thereafter, control data for the printing apparatus 4 is generated from the data processed by the block image processing unit 14 and printing is performed, or the data after the processing by the block image processing unit 14 is performed in a predetermined file format. A file is generated and transmitted by the communication device 5 or stored in the storage device 6.

  As described above, according to the first embodiment, the raster writing unit 12 shifts the address of the line data of a plurality of colors by the offset corresponding to the interval between the line sensors 1R, 1G, and 1B. Data are written in the buffer memory 3 in order along the sub-scanning direction. The block reading unit 13 reads the block data 31R, 31G, and 31B from the plurality of line data for each color written in the buffer memory 3, and the block image processing unit 14 reads the block data 31R, 31G, and 31B. Predetermined data processing.

  Thereby, line-to-line correction is performed at the time of writing to the buffer memory 3, and block conversion is performed at the time of reading from the buffer memory 3. Therefore, line correction and block conversion are performed by one writing and one reading to the buffer memory 3, so that only one buffer memory 3 is required and memory access to the buffer memory 3 is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory. In addition, since the number of buffer memories 3 can be one, the cost of the apparatus can be reduced.

Embodiment 2. FIG.

  FIG. 4 is a block diagram showing the configuration of the image forming apparatus according to Embodiment 2 of the present invention. In the fourth embodiment, the image forming apparatus is a multifunction machine. As shown in FIG. 4, the image forming apparatus includes a line scanner 1, an image processing device 31, a buffer memory 3, a printing device 4, a communication device 5, and a storage device 6. The line scanner 1, the buffer memory 3, the printing device 4, the communication device 5, and the storage device 6 are the same as those in the first embodiment.

  The image processing apparatus 31 uses one buffer memory 3 to perform inter-line correction and block conversion, and performs data processing on image data for each block. The image processing device 31 includes an ASIC and / or a computer, and realizes each arithmetic processing unit. In the second embodiment, the image processing apparatus 31 includes an inter-line correction address calculation unit 41, a raster writing unit 42, a block reading unit 43, and a block image processing unit 44.

  The inter-line correction address calculation unit 41 is an arithmetic processing unit that calculates an address shifted by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B. This offset is calculated based on the scanning speed in the sub-scanning direction and the number of lines obtained from the intervals between the line sensors 1R, 1G, 1B.

  The raster writing unit 42 is an arithmetic processing unit that sequentially writes the line data of a plurality of colors by the line sensors 1R, 1G, and 1B of the line scanner 1 in the buffer memory 3 in order along the sub-scanning direction. In the second embodiment, the raster writing unit 42 sequentially writes line data of colors corresponding to the buffer areas in each of the plurality of buffer areas in the buffer memory 3.

  The block reading unit 43 shifts the address by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B, and from the plurality of line data for each color written in the buffer memory 3, block data (that is, in the original image). This is an arithmetic processing section for reading out RGB block data for the same position. In the second embodiment, the block reading unit 43 reads block data from the address calculated by the interline correction address calculation unit 41.

  The block image processing unit 44 is an arithmetic processing unit that performs predetermined data processing on the block data read by the block reading unit 43. In the second embodiment, the block image processing unit 44 compresses block data by the JPEG method, for example.

  Next, the operation of the above apparatus will be described.

  In the image processing apparatus 31, the raster writing unit 42 writes line data for each of RGB in order in the buffer areas 21 R, 21 G, and 21 B of the buffer memory 3 without performing line correction when writing line data.

  When the line sensors 1R, 1G, and 1B are arranged in the order of RGB in the scan direction, the leading addresses Xr, Xg, and Xb of the area in which the i-th line data is written for each color of RGB are calculated as follows.

Xr = Xr0 + (i−1) × L
Xg = Xg0 + (i−1) × L
Xb = Xb0 + (i−1) × L

  In order to read the block data, the inter-line correction address calculation unit 41 calculates the address of the buffer memory 3 from which the RGB block data is read. At this time, the inter-line correction address calculation unit 41 calculates an address shifted by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B.

  The block reading unit 43 reads block data from the address in the buffer memory 3 calculated by the interline correction address calculation unit 41.

  FIG. 5 is a diagram for explaining reading of block data by the block reading unit 43 in FIG. When the line sensors 1R, 1G, and 1B are arranged in the order of RGB in the scan direction, as shown in FIG. 5, the offset is zero for the R block data 31R, and the G block data 31G is , The offset is calculated as (N1−N2) × L, the block data 31G is read from the address that is behind that offset, and the B block data 31B is calculated as an offset of N1 × L. The block data 31B is read from the subsequent address. That is, in the first embodiment, the relative addresses of the block data 31R, 31G, and 31B have the same value, but in the second embodiment, the relative addresses of the block data 31R, 31G, and 31B are shifted by the above-described offset amount.

  Then, the block image processing unit 44 performs predetermined processing (for example, JPEG compression) on the block data 31R, 31G, 31B.

  Depending on the type of processing in the block image processing unit 44, the pixels belonging to the jth block data 31R, 31G, 31B and the pixels belonging to the previous and / or subsequent block data 31R, 31G, 31B The block data 31R, 31G, 31B may be read so as to overlap, or the block data 31R, 31G, 31B may be read so as not to overlap.

  Thereafter, control data for the printing apparatus 4 is generated from the data processed by the block image processing unit 44 and printing is performed, or the data after processing by the block image processing unit 44 is performed in a predetermined file format. A file is generated and transmitted by the communication device 5 or stored in the storage device 6.

  As described above, according to the second embodiment, the raster writing unit 42 writes line data of a plurality of colors in the buffer memory 3 in order along the sub-scanning direction. Then, the block reading unit 43 shifts the address by an offset corresponding to the interval between the line sensors 1R, 1G, and 1B, and from the plurality of line data for each color written in the buffer memory 3, the block data 31R, 31G, 31B is read, and the block image processing unit 44 performs predetermined data processing on the block data 31R, 31G, and 31B.

  Thereby, line-to-line correction and block conversion are performed when reading from the buffer memory 3. Therefore, line correction and block conversion are performed by one writing and one reading to the buffer memory 3, so that only one buffer memory 3 is required and memory access to the buffer memory 3 is reduced. For this reason, image data obtained by color scanning can be processed for each block with a small memory access using a small-sized buffer memory. In addition, since the number of buffer memories 3 can be one, the cost of the apparatus can be reduced.

  Each embodiment described above is a preferred example of the present invention, but the present invention is not limited to these, and various modifications and changes can be made without departing from the scope of the present invention. It is.

  For example, in the above-described embodiments, the order of the line sensors 1R, 1G, and 1B is R, G, and B, but other orders may be used. Further, the line sensors 1R, 1G, and 1B may be arranged at equal intervals or may be arranged at different intervals.

  In each of the above embodiments, the block image processing units 14 and 44 may perform filter processing, interpolation processing, edge detection processing, and the like on the block data.

  The present invention can be applied to an image forming apparatus such as a printer, a copier, a scanner, or a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Line scanner 1R, 1G, 1B Line sensor 2 Image processing apparatus 3 Buffer memory 11, 41 Interline correction address calculation part 12, 42 Raster writing part 13, 43 Block reading part 14, 44 Block image processing part 21R, 21G, 21B Buffer area 31R, 31G, 31B Block data

Claims (8)

A raster writing unit for sequentially writing the line data of a plurality of colors by a line sensor of a plurality of colors in the line scanner by an offset corresponding to the interval between the line sensors and sequentially writing the data in the buffer memory along the sub-scanning direction When,
A block reading unit that reads block data from a plurality of line data for each color written in the buffer memory;
A block image processing unit that performs predetermined data processing on the block data read by the block reading unit;
An image processing apparatus comprising: An interline correction address calculating unit that calculates an address shifted by an offset corresponding to the interval of the line sensors;
The raster writing unit writes the line data to the address calculated by the inter-line correction address calculation unit;
The image processing apparatus according to claim 1. A raster writing section for sequentially writing a plurality of color line data from a plurality of color line sensors in the line scanner along the sub-scanning direction to the buffer memory;
A block reading unit that reads block data from a plurality of line data for each color written in the buffer memory while shifting an address by an offset corresponding to the interval between the line sensors;
A block image processing unit that performs predetermined data processing on the block data read by the block reading unit;
An image processing apparatus comprising: An interline correction address calculating unit that calculates an address shifted by an offset corresponding to the interval of the line sensors;
The block reading unit reads the block data from the address calculated by the inter-line correction address calculation unit;
The image processing apparatus according to claim 3.   4. The raster writing unit sequentially writes the line data of a color corresponding to the buffer area into each of a plurality of buffer areas in the buffer memory. Image processing device.   The image processing apparatus according to claim 1, wherein the block image processing unit compresses the block data by a JPEG method. A line scanner that outputs line data of multiple colors by a line sensor of multiple colors;
Buffer memory,
A raster writing unit for sequentially writing the line data of the plurality of colors by shifting an address by an offset corresponding to the interval of the line sensors and sequentially writing the buffer memory along the sub-scanning direction;
A block reading unit that reads block data from a plurality of line data for each color written in the buffer memory;
A block image processing unit that performs predetermined data processing on the block data read by the block reading unit;
An image forming apparatus comprising: A line scanner that outputs line data of multiple colors by a line sensor of multiple colors;
Buffer memory,
A raster writing section for sequentially writing the line data of the plurality of colors into the buffer memory along a sub-scanning direction;
A block reading unit that reads block data from a plurality of line data for each color written in the buffer memory while shifting an address by an offset corresponding to the interval between the line sensors;
A block image processing unit that performs predetermined data processing on the block data read by the block reading unit;
An image forming apparatus comprising:

Images