JP5135382B2 - Image processing device - Google Patents

Description

  The present invention relates to storage of image data using descriptors.

  In image data filter processing (smoothing, enlargement / reduction, edge enhancement, etc.), when image data expanded in the page memory is read into the line memory along the main scanning direction and filtered, it is expanded in the page memory. There has been proposed a technique of dividing the processed image data into blocks and performing filter processing for each block (see Patent Document 1). According to this technique, since image data is processed in units of blocks, the size of the line memory in the main scanning direction can be reduced.

  When image data (for example, image data obtained by reading a document with a scanner) is stored in the main memory, if the image data is large, it is not always possible to secure a storage area for continuous addresses. Therefore, the memory space is efficiently used by dividing the image data into a plurality of pieces and storing them in a storage area where the addresses are discontinuous. In this case, a descriptor is used so that data stored in storage areas with discontinuous addresses can be connected and returned to the original image data (see Patent Document 2).

JP 2000-251065 A Japanese Patent Laying-Open No. 2005-250996 (paragraphs 0023 to 0026, FIGS. 2 and 3)

  Descriptors are used to connect the data stored in storage areas with discontinuous addresses and return to the original image data. However, in order to efficiently use the memory space, a large number of descriptors are used for one image data. (Eg thousands). If the access time to the target descriptor can be shortened, the image data can be processed efficiently (for example, the access time to the data of each pixel stored in the main memory).

  It is an object of the present invention to provide an image processing apparatus that can shorten the access time to a descriptor stored in a main memory.

  An image processing apparatus according to an aspect of the present invention that achieves the above object is allocated to a main memory and each of a plurality of block areas arranged in the main scanning direction and the sub-scanning direction. A block descriptor processing unit for processing a plurality of block descriptors including block area information, which is information on the number of pixels in the main scanning direction and the sub-scanning direction, and the coordinates of the leading pixel, and pixels in the main scanning direction from the block area A band descriptor processing unit for processing a plurality of band descriptors each of which is a band-shaped band region having a large number of pixels and a small number of pixels in the sub-scanning direction and allocated to each of the plurality of band regions arranged in the sub-scanning direction; A plurality of image data to be stored in the plurality of band regions corresponding to each of the plurality of band regions A processing unit that performs processing by dividing into band area data, the process of dividing the band area data into a plurality of divided data and storing different addresses in the main memory, each of the plurality of band area data The band descriptor processing unit for the band descriptor assigned to the band region corresponding to the band region data when the image data is stored in the main memory. Then, the address information on the main memory of the data of the first pixel of each of the plurality of divided data and the divided data information which is information of the number of pixels of each of the plurality of divided data are added and stored in the main memory. A process is performed on each of the plurality of band descriptors, and the plurality of band descriptors are executed. The descriptors are ordered, and each of the plurality of band descriptors stored in the main memory includes address information on the main memory of the next sequential band descriptor, and the block descriptor processing unit When the image data is stored in the main memory, if the address on the main memory of the band descriptor assigned to the band area including the first pixel of the block area is a band descriptor association address, A process of storing a block descriptor including information on descriptor association addresses in the main memory is executed in each of the plurality of block descriptors.

  According to the present invention, when image data is divided into divided data and stored in the main memory, a plurality of band descriptors and a plurality of block descriptors are stored in the main memory. Each of the plurality of block descriptors stored in the main memory includes information on band descriptor association addresses. Therefore, the address of the band descriptor assigned to the band area including the first pixel of the block area can be known from the block descriptor assigned to the block area.

  Each of the plurality of band descriptors stored in the main memory includes address information on the main memory of the next sequential band descriptor, so that the target band descriptor can be accessed without using the block descriptor. However, in this case, the band descriptors must be searched in order from the first band descriptor. According to the present invention, by using a block descriptor, it is possible to start a search from an intermediate band descriptor and access a target band descriptor. Accordingly, the access time to the band descriptor can be shortened.

  In the above configuration, the plurality of block descriptors are ordered and an address on the main memory is assigned in advance for each of the plurality of block descriptors, and the next block descriptor in the main memory on the main memory is assigned in advance. A block descriptor storage unit in which the plurality of block descriptors including address information, the block area information, and the band descriptor association address information are stored in advance, and the block descriptor processing unit stores the image in the main memory. When data is stored, the plurality of block descriptors stored in the block descriptor storage unit can be read and stored in the main memory.

  According to this configuration, since a plurality of block descriptors are created in advance and stored in the block descriptor storage unit, a plurality of block descriptors are generated as compared with the case where a plurality of block descriptors are created when image data is stored in the main memory. The process of storing the block descriptor in the main memory can be speeded up.

  In the above configuration, for an image formed on the basis of the image data stored in the main memory, the coordinates in the main scanning direction and the sub-scanning direction where the nth pixel (n is a positive integer) is located, A coordinate calculation unit for calculating based on the number of pixels in the main scanning direction of the image, a block descriptor reading unit for reading the plurality of block descriptors stored in the main memory, and the n calculated by the coordinate calculation unit Based on the coordinates of the th pixel and the block area information included in each of the plurality of block descriptors read by the block descriptor reading unit, the block area to which the nth pixel belongs among the plurality of block areas. The block area specifying unit to be specified and the block area specified by the block area specifying unit are allocated. The block descriptor, and the band descriptor reading unit for reading a band descriptors stored in the band descriptor association address contained in the block descriptor from the main memory may comprise.

  According to this configuration, when the data of the nth pixel stored in the main memory is accessed using the band descriptor, the band assigned to the band area including the first pixel of the block area to which the nth pixel belongs. You can start with a descriptor.

  Here, when the pixels arranged in the main scanning direction in the image are rows, the n-th pixel is counted from the first pixel in the first row to the last pixel in the first row, and then the first pixel in the second row. To the last pixel in the second row, and the third and subsequent rows are counted in the same manner.

  In the above configuration, the nth pixel in the plurality of band regions based on the number of pixels in the subscanning direction of the band region and the coordinates of the nth pixel in the subscanning direction calculated by the coordinate calculation unit. A band region specifying unit that specifies a position of the n-th pixel in the sub-scanning direction in the band region, and a coordinate in the main scanning direction of the n-th pixel calculated by the coordinate calculation unit, The nth pixel specified by the band region specifying unit based on the position in the sub-scanning direction of the nth pixel specified by the band region specifying unit and the number of pixels in the main scanning direction of the image data A pixel number calculation unit for calculating the number of pixels from the first pixel of the band region to which the image belongs to the nth pixel, and the band descriptor read by the band descriptor reading unit A divided data specifying unit for specifying divided data to which the data of the nth pixel belongs among the plurality of divided data, based on the divided data information included and the number of pixels calculated by the pixel number calculating unit; Based on the number of pixels calculated by the pixel number calculation unit, the n-th pixel data on the main memory from the address on the main memory of the data of the first pixel of the divided data specified by the divided data specification unit An address specifying unit for specifying the address of the address.

  According to this configuration, when accessing the data of the nth pixel stored in the main memory, it starts from the band descriptor assigned to the band area including the first pixel of the block area to which the nth pixel belongs. . Accordingly, it is possible to shorten the access time to the n-th pixel data as compared to the case where the n-th pixel data is accessed in order from the first band descriptor.

  According to the present invention, it is possible to shorten the access time to the descriptor stored in the main memory.

It is a block diagram which shows the hardware constitutions of the image processing apparatus which concerns on one Embodiment of this invention. It is a conceptual diagram of the block area | region and band area | region used by this embodiment. FIG. 3 is a diagram showing a plurality of band descriptors assigned to each of a plurality of band regions shown in FIG. 2. FIG. 3 is a diagram showing a plurality of block descriptors assigned to each of a plurality of block areas shown in FIG. 2. It is a figure which shows the band area data M22 which is the image data corresponding to band area BA22 among the image data stored in a main memory. It is a flowchart explaining the process which stores image data in the main memory using the image processing apparatus which concerns on this embodiment. It is a flowchart explaining the access to the data of the nth pixel contained in the image data stored in the main memory using the image processing apparatus which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a hardware configuration of an image processing apparatus 1 according to an embodiment of the present invention. The image processing apparatus 1 is applied to a multifunction machine, a copier, and the like, and includes a CPU (Central Processing Unit) 3, a main memory 7, a read-only memory 9, and an ASIC (Application Specific Integrated Circuit) 11. Are connected by a bus 13. Further, the image processing apparatus 1 includes a line sensor 5 and is connected to the ASIC 11 by a dedicated bus 14.

  The CPU 3 executes control necessary for operating the image processing apparatus 1 on the hardware constituting the image processing apparatus 1. The line sensor 5 is an element constituting the scanner of the image processing apparatus 1 and reads an image of a document and outputs image data. The line sensor 5 is realized by, for example, a CCD (Charge Coupled Device) sensor.

  The main memory 7 is a RAM (Random Access Memory), and is used for temporary storage of data generated during execution of software, storage of application software, and the like. The main memory 7 is realized by a DRAM (Dynamic Random Access Memory), for example.

  The read-only memory 9 is a ROM (Read Only Memory) and stores software and the like necessary for controlling the operation of the image processing apparatus 1. The read-only memory 9 is realized by a flash memory or the like.

  The ASIC 11 is dedicated to image processing and is used for various processing (filters and the like) of image data. FIG. 1 shows functional blocks related to the present embodiment. The ASIC 11 includes a division processing unit 21, a band descriptor processing unit 23, a block descriptor processing unit 25, and a pixel data access unit 27. As a premise for understanding these, a band area, a block area, a band descriptor, and a block descriptor will be described.

  FIG. 2 is a conceptual diagram of a block area and a band area used in this embodiment. A plurality of, for example, 16 block areas BL1 to BL16 are arranged in the main scanning direction D1 and the sub-scanning direction D2. When it is necessary to distinguish a plurality of block areas, they are described as block areas BL1 to BL16, and when it is not necessary to distinguish between them, they are described as block areas BL. Four block areas BL are arranged in the main scanning direction D1, and four block areas BL are arranged in the sub scanning direction D2. Each block region BL has the same number of pixels in the main scanning direction D1, and each block region BL has the same number of pixels in the sub-scanning direction D2. Accordingly, the number of pixels (size) in each block region BL is the same. In the present embodiment, the main scanning direction D1 can also be referred to as the x direction and the sub scanning direction D2 as the y direction.

  A plurality of band areas BA are arranged side by side along the sub-scanning direction D2. When it is necessary to distinguish a plurality of band areas, they are described as band areas BA1, BA2,...

  The band area BA is a band-shaped area extending in the main scanning direction D1, and has a larger number of pixels in the main scanning direction D1 and a smaller number of pixels in the sub-scanning direction D2 than the block area BL. Of the image data output from the line sensor 5, image data obtained by scanning a predetermined number of scanning lines (for example, 64 scanning lines) corresponds to one band area BA. Therefore, the number of pixels in the main scanning direction D1 of the band area BA is the same as the number of pixels in the main scanning direction D1 of the image data, and the number of pixels in the sub-scanning direction D2 of the band area BA is the number of scanning lines ( For example, 64).

  The number of pixels defined by the plurality of block areas BL arranged in the main scanning direction D1 and the sub-scanning direction D2 is equal to the number of pixels defined by the plurality of band areas BA arranged in the sub-scanning direction D2. This corresponds to the number of pixels of the image data developed in the page memory. The number of pixels and the blocks in the sub-scanning direction D2 of the band area BA so that the band area BA is not located on the boundaries between the block areas BL in the main scanning direction D1 (for example, the block areas BL1 to BL4 and the block areas BL5 to BL8). The number of pixels in the sub-scanning direction D2 of the region BL is determined.

  FIG. 3 is a diagram showing a plurality of band descriptors assigned to each of the plurality of band areas BA shown in FIG. When it is necessary to distinguish a plurality of band descriptors, they are described as band descriptors BAD1, BAD2,..., And when it is not necessary to distinguish between them, they are described as band descriptors BAD.

  The order of the plurality of band descriptors BAD is determined according to the order in which the plurality of band areas BA are arranged in the sub-scanning direction D2. For example, the first band descriptor BAD1 is a band descriptor assigned to the band area BA1, the second band descriptor BAD2 is a band descriptor assigned to the band area BA2, and the 22nd band descriptor BAD22 is a band descriptor. This is a band descriptor assigned to the area BA22.

  When the image data is stored in the main memory 7, the plurality of band descriptors BAD are stored in the main memory 7. An address on the main memory 7 is determined in advance for each of the plurality of band descriptors BAD. For example, an address Add51 on the main memory 7 is assigned in advance to the band descriptor BAD1 assigned to the band area BA1.

  Each band descriptor BAD includes address information on the main memory 7 of the band descriptor BAD in the next order, and divided data information (address information on the main memory 7 of each head pixel data of a plurality of divided data and a plurality of pieces of data). Information on the number of pixels of each divided data). The divided data information will be described later.

  FIG. 4 is a diagram showing a plurality of block descriptors assigned to each of the plurality of block areas BL shown in FIG. When it is necessary to distinguish a plurality of block descriptors, they are described as block descriptors BLD1, BLD2,..., And when it is not necessary to distinguish between them, they are described as block descriptors BLD.

  The order of the plurality of block descriptors BLD is determined according to the order of the plurality of block areas BL. That is, the first block descriptor BLD1 is a block descriptor assigned to the block area BL1, the second block descriptor BLD2 is a block descriptor assigned to the block area BL2,..., The 16th block descriptor BLD16. Is a block descriptor assigned to the block area BL16.

  When the image data is stored in the main memory 7, the plurality of block descriptors BLD are stored in the main memory 7. An address on the main memory 7 is assigned in advance for each of the plurality of block descriptors BLD. For example, the address Add31 on the main memory 7 is assigned in advance to the block descriptor BLD1 assigned to the block area BL1.

  Each of the plurality of block descriptors BLD includes address information on the main memory 7 of the next block descriptor BLD, block area information, and band descriptor-related address information. These pieces of information will be described using the block descriptor BLD5 as an example. The address on the main memory 7 of the next block descriptor BLD is the address Add36 on the main memory 7 of the block descriptor BLD6.

  The block area information is composed of the number (size) of pixels in the main scanning direction D1 and sub-scanning direction D2 for the block area BL to which the block descriptor BLD is assigned, and the coordinates (starting coordinates) of the first pixel in the block area BL. The In this embodiment, the number of pixels in the main scanning direction D1 of each block region BL is the same, and the number of pixels in the sub-scanning direction D2 of each block region BL is also the same. The coordinates of the first pixel in the block descriptor BLD5 indicate the coordinates in the main scanning direction D1 and the sub-scanning direction D2 of the first pixel P in the block region BL5 as shown in FIG.

  The band descriptor association address information is information on the address on the main memory 7 of the band descriptor BAD assigned to the band area BA including the first pixel of the block area BL to which the block descriptor BLD is assigned. As shown in FIG. 2, since the first pixel P of the block area BL5 is located in the band area BA22, it means the address Add72 on the main memory 7 of the band descriptor BAD22 assigned to the band area BA22. This completes the description of the band area BA, block area BL, band descriptor BAD, and block descriptor BLD.

  The division processing unit 21 included in the ASIC 11 illustrated in FIG. 1 divides the image data stored in the main memory 7 into a plurality of band area data corresponding to each of the plurality of band areas BA illustrated in FIG. It is. The division processing unit 21 performs a process of dividing the band area data into a plurality of divided data and storing the data in the main memory 7 with different addresses for each of the plurality of band area data.

  The processing in the division processing unit 21 will be described using the band area BA22 as an example. FIG. 5 is a diagram showing band area data M22 which is image data corresponding to the band area BA22 among the image data stored in the main memory 7. The band area data corresponds to the band area BA, for example, the band area data M1 corresponds to the band area BA1, and the band area data M2 corresponds to the band area BA2. When it is necessary to distinguish a plurality of band area data, it is described as band area data M1, M2,..., And when it is not necessary to distinguish between them, it is described as band area data M.

  The division processing unit 21 divides the band area data M22 into a plurality of divided data, for example, five divided data m1 to m5, and stores them in the main memory 7 with different addresses. As described above, by dividing the image data finely and storing the data in empty addresses in the main memory 7, the memory space of the main memory 7 can be used effectively.

  The band descriptor processing unit 23 processes a plurality of band descriptors BAD assigned to each of the plurality of band areas BA shown in FIG. Specifically, when the image data is stored in the main memory 7, the band descriptor processing unit 23 supplies the divided data information to the band descriptor BAD assigned to the band area BA corresponding to the band area data M. In addition, the processing stored in the main memory 7 is executed in each of the plurality of band descriptors BAD.

  The divided data information is information on the address on the main memory 7 of the data of the first pixel of each of the plurality of divided data and information on the number of pixels of each of the plurality of divided data. This will be described using the band region data M22 shown in FIG. 5 as an example. The leading pixels of the divided data m1 to m5 are designated as leading pixels p1 to p5, respectively. Here, the leading pixel p1 of the divided data m1 matches the leading pixel P of the block area BL5 shown in FIG. 2, and matches the leading pixel of the band area BA22 (not shown).

  The divided data information of the band area data M22 includes the address on the main memory 7 where the data of the first pixel p1 of the divided data m1 is stored, the number of pixels in the area corresponding to the divided data m1 (for example, 10000), and the divided data m2 The address of the main memory 7 storing the data of the first pixel p2 and the number of pixels in the area corresponding to the divided data m2 (for example, 20000),..., The data of the first pixel p5 of the divided data m5 are stored. It is configured by the number of pixels in the area corresponding to the address on the main memory 7 and the divided data m5.

  The band descriptor processing unit 23 includes a storage unit 29. In the storage unit 29, templates of a plurality of band descriptors BAD shown in FIG. 3 are stored in advance. In this template, each of the plurality of band descriptors BAD has address information on the main memory 7 of the next band descriptor BAD, but does not have divided data. The band descriptor processing unit 23 performs processing for adding the divided data information of the band area data M to the template of the band descriptor BAD stored in the storage unit 29 to generate the band descriptor BAD shown in FIG. 7 is stored.

  As shown in FIG. 3, each band descriptor BAD has address information and divided data information on the main memory 7 of the band descriptor in the next order. Therefore, the band descriptor BAD1 is read, and based on the divided data information included in the band descriptor BAD1, a plurality of pieces of divided data are connected to form band area data M1, and then the band descriptor BAD2 is read and included in the band descriptor BAD2. Based on the divided data information to be obtained, a plurality of pieces of divided data are connected to form band area data M2, and the same processing is repeated for the remaining band descriptor BAD, thereby returning to the image data before being stored in the main memory 7. Can do.

  When image data is stored in the main memory 7, the block descriptor processing unit 25 executes processing for storing the block descriptor BLD including the band descriptor association address information in the main memory 7 in each of the plurality of block descriptors BLD. To do. The block descriptor processing unit 25 includes a storage unit 31 (an example of a block descriptor storage unit). The storage unit 31 includes a plurality of block descriptors BLD shown in FIG. 4 (a plurality of block descriptors BLD including address information on the main memory 7 of the next block descriptor, block area information, and band descriptor-related address information). Is stored in advance. A plurality of block descriptors BLD shown in FIG. 4 may be stored in the read-only memory 9.

  The block descriptor BLD that does not include the band descriptor association address information is stored in the storage unit 31 in advance, and the block descriptor processing unit 25 reads the block descriptor BLD from the storage unit 31, and the band descriptor association address information is stored in the block descriptor BLD. May be added and stored in the main memory 7.

  The pixel data access unit 27 performs access processing to the pixel data that is data of each pixel constituting the image with respect to the image data that is divided into divided data and stored in the main memory 7. The pixel data access unit 27 includes a coordinate calculation unit 33, a block area specifying unit 35, a band descriptor reading unit 37, a block descriptor reading unit 39, a band area specifying unit 41, a pixel number calculating unit 43, a divided data specifying unit 45, and an address specifying unit. 47.

  The coordinate calculation unit 33 calculates the coordinates in the main scanning direction D1 and the sub-scanning direction D2 for the pixels corresponding to the pixel data to be accessed. That is, the coordinate calculation unit 33 in the main scanning direction D1 and the sub-scanning direction D2 in which the nth pixel (n is a positive integer) is located in the image formed based on the image data stored in the main memory 7. The coordinates are calculated based on the number of pixels in the main scanning direction D1 of the image.

  The block area specifying unit 35 specifies the block area BL to which the nth pixel belongs. More specifically, the block area specifying unit 35 is based on the coordinates of the nth pixel calculated by the coordinate calculation unit 33 and the block area information included in each of the plurality of block descriptors BLD read from the main memory 7. Thus, the block region BL to which the nth pixel belongs among the plurality of block regions BL is specified.

  For the block descriptor BLD assigned to the block area BL specified by the block area specifying unit 35, the band descriptor reading unit 37 uses the band descriptor BAD stored in the band descriptor association address included in the block descriptor BLD as the main memory. Read from 7.

  The block descriptor reading unit 39 reads a plurality of block descriptors stored in the main memory 7.

  The band area specifying unit 41 specifies the band area BA to which the nth pixel belongs among the plurality of band areas BA, and the position of the nth pixel in the band area BA in the sub-scanning direction D2.

  The pixel number calculation unit 43 calculates the number of pixels from the first pixel to the nth pixel of the band area BA to which the nth pixel specified by the band area specifying unit 41 belongs.

  The divided data specifying unit 45 specifies divided data to which the data of the nth pixel belongs among the plurality of divided data in the divided data information included in the band descriptor BAD read by the band descriptor reading unit 37.

  The address specifying unit 47 specifies the address on the main memory 7 of the data of the nth pixel from the address on the main memory 7 of the data of the first pixel of the divided data specified by the divided data specifying unit 45.

  Next, processing for storing image data in the main memory 7 using the image processing apparatus 1 according to the present embodiment will be described. FIG. 6 is a flowchart for explaining this process. By scanning the document in the main scanning direction D1 by the line sensor 5 shown in FIG. 1 and reading the document one scanning line at a time, the image data of the document is output from the line sensor 5 (step S1).

  The block descriptor processing unit 25 reads a plurality of block descriptors BLD shown in FIG. 4 stored in the storage unit 31, and stores each block descriptor BLD at a pre-assigned address on the main memory 7 (step S3).

  In step S <b> 1, image data obtained by scanning a predetermined number of scanning lines (for example, 64 scanning lines) among the image data output from the line sensor 5 corresponds to the band region data M. The image data output from the line sensor 5 is sent to the division processing unit 21. When the band area data M1 (corresponding to the band area BA1) is accumulated in the buffer of the division processing unit 21, the division processing unit 21 divides the band area data M1 into a plurality of division data and makes the main memory 7 have different addresses. (Step S5).

  The band descriptor processing unit 23 reads the template of the band descriptor BAD1 stored in the storage unit 29, adds divided data information about a plurality of divided data constituting the band area data M1, and stores it in the main memory 7 ( Step S7).

  The division processing unit 21 determines whether the next band area data M (here, band area data M2) is stored in the buffer of the division processing unit 21 (step S9). If the division processing unit 21 determines that the next band area data M is accumulated (Yes in step S9), the process returns to step S5. On the other hand, if the division processing unit 21 determines that the next band area data M is not accumulated (No in step S9), that is, the last band area data M is processed in steps S5 and S7. In this case, the process for storing the image data in the main memory 7 ends.

  As described above, according to the image processing apparatus 1 according to the present embodiment, when the image data is divided into divided data and stored in the main memory 7, a plurality of band descriptors BAD and a plurality of block descriptors BLD are stored in the main memory 7. Is stored. Each of the plurality of block descriptors BLD stored in the main memory 7 includes information of band descriptor association addresses. Therefore, the address of the band descriptor BAD assigned to the band area BA including the first pixel of the block area BL can be known from the block descriptor BLD assigned to the block area BL.

  Each of the plurality of band descriptors BAD stored in the main memory 7 includes the address information on the main memory 7 of the band descriptor BAD in the next order, so that the target band can be obtained without using the block descriptor BLD. Descriptor BAD can be accessed. However, in this case, the band descriptor BAD must be searched in order from the first band descriptor BAD. According to the present embodiment, by using the block descriptor BLD, the search can be started from the band descriptor BAD in the middle and the target band descriptor BAD can be accessed. Therefore, the access time to the band descriptor BAD can be shortened.

  Further, as described in step S3, since a plurality of block descriptors BLD are created in advance and stored in the storage unit 31 (block descriptor storage unit), a plurality of pieces of image data are stored when the main memory 7 stores image data. Compared to the case of creating the block descriptor BLD, the process of storing a plurality of block descriptors BLD in the main memory 7 can be accelerated.

  Next, access to the data of the nth pixel (n is a positive integer) included in the image data stored in the main memory 7 will be described. FIG. 7 is a flowchart for explaining this access. Here, the n-th pixel is the 700,000th pixel, the number of pixels in the main scanning direction D1 of the image data (in other words, the number of pixels in the main scanning direction D1 of the band area BA) is 500, and the scanning line corresponding to the band area data M The number is 64.

The coordinate calculation unit 33 uses the coordinates of the main scanning direction D1 and the sub-scanning direction D2 in which the 700,000th pixel is located in the image formed by the image data stored in the main memory 7, and the coordinates in the main scanning direction D1 of the image data. Calculation is performed based on the number of pixels (500) (step S21).
700,000 ÷ 500 = 1400
1400 means that the coordinate (x coordinate) in the main scanning direction D1 is 0, and the coordinate (y coordinate) in the sub scanning direction D2 is 1400. Therefore, as shown in FIG. 2, the coordinates where the 700,000th pixel Q is located are (0, 1400).

  The block descriptor reading unit 39 reads a plurality of block descriptors BLD of the image data from the main memory 7 (step S23).

  The block area specifying unit 35 is based on the coordinates (0, 1400) of the 700,000th pixel Q calculated in step S21 and the block area information included in each of the plurality of block descriptors BLD read in step S23. Among the plurality of block areas BL, the block area BL to which the 700,000th pixel Q belongs is specified (step S25).

  As shown in FIG. 2, the number of block areas BL in the main scanning direction D1 is 4, and the number of pixels in the sub-scanning direction D2 of the block area BL is the number of pixels in the sub-scanning direction D2 of 21 band areas BA. . Therefore, in the block area information shown in FIG. 4, for each block area BL, the number of pixels in the main scanning direction D1 is 125 (= 500/4), and the number of pixels in the sub-scanning direction D2 is 1344 (= 64 × 21).

The coordinates where the 700,000th pixel Q is located are (0, 1400) (step S21). The following relationship is established in the main scanning direction D1.
0 <125
Therefore, when the coordinate in the main scanning direction D1 is 0, it belongs to one of the block areas BL1, BL5, BL9, BL13.

The following relationship is established in the sub-scanning direction D2.
1344 <1400 <2688
Therefore, when the coordinate in the sub-scanning direction D2 is 1400, it belongs to one of the block areas BL5, BL6, BL7, and BL8.

  Since there is a block region BL5 in both the main scanning direction D1 and the sub-scanning direction D2, the 70th pixel Q belongs to the block region BL5 as shown in FIG.

  Next, the band descriptor reading unit 37 sets the band descriptor BAD22 stored in the band descriptor association address Add72 included in the block descriptor BLD5 for the block descriptor BLD5 assigned to the block area BL5 specified in step S25 as the main. Read from the memory 7 (step S27).

Next, the band area specifying unit 41 specifies the band area BA to which the 700,000th pixel Q belongs among the plurality of band areas BA, and the position of the 700,000th pixel Q in the band area BA in the sub-scanning direction D2 ( Step S29). The position of the 700,000th pixel Q in the sub-scanning direction D2 means the row where the 700,000th pixel Q is located in the band area BA. The identification in step S29 is executed based on the number of pixels 64 in the sub-scanning direction D2 of the band area BA and the coordinates 1400 in the sub-scanning direction D2 of the 700,000th pixel Q calculated in step S21.
1400 ÷ 64 = 21.875
21.875 means 21 band areas BA + 0.875 band areas BA. Therefore, the 700,000th pixel Q belongs to the band area BA22 which is the 22nd band area BA. The position of the 700,000th pixel in the band area BA22 in the sub-scanning direction D2 is the 56th (= 64 × 0.875) line of the band area BA22.

Next, the pixel number calculation unit 43 calculates the number of pixels from the first pixel of the band area BA22 to which the 700,000th pixel Q specified in step S29 belongs (that is, the first pixel p1 of the divided data m1) to the 700,000th pixel Q. Calculation is performed (step S31). This calculation is based on the coordinate 0 in the main scanning direction D1 of the 700,000th pixel Q calculated in step S21, the position in the sub-scanning direction D2 specified in step S29 (line 56), and the main scanning direction D1 of the image data. This is executed based on the number of pixels (in other words, the number of pixels in the main scanning direction D1 of the band area BA) 500.
0 + 500 × 56 = 28000
28000 is the number of pixels calculated in step S31.

Next, using the divided data information included in the band descriptor BAD22 shown in FIG. 3 read in step S27, the divided data specifying unit 45 stores the 700,000th pixel data Q among the plurality of divided data m1 to m5. The divided data to which it belongs is specified (step S33). The identification is performed based on the number of pixels (FIG. 5) of each of the plurality of divided data m1 to m5 included in the divided data information of the band descriptor BAD22 and the number of pixels 28000 calculated in step 31.
10000 (number of pixels of the divided data m1) <28000
The data of the 700,000th pixel Q does not belong to the divided data m1.
10000 + 20000 (number of pixels of the divided data m2)> 28000
Therefore, the data of the 700,000th pixel Q belongs to the divided data m2 as shown in FIG.

  Next, the address specifying unit 47 specifies the address on the main memory 7 of the data of the 700,000th pixel Q from the address on the main memory 7 of the data of the first pixel p2 of the divided data m2 (step S35). This identification is executed based on the number of pixels 28000 calculated in step S31.

  Here, the address on the main memory 7 of the data of the 18000 (= 28000−10000) th pixel from the address on the main memory 7 of the data of the first pixel p2 is the address of the data of the 700,000th pixel Q.

  As described above, according to the present embodiment, when accessing the data of the nth pixel stored in the main memory 7 using the band descriptor BAD, by using the block descriptor BLD, It can start from the band descriptor BAD assigned to the band area BA including the first pixel of the block area BL to which the nth pixel belongs. On the other hand, if the block descriptor BLD is not used, the band descriptor BAD corresponding to the nth pixel data must be searched in order from the first band descriptor BAD to access the nth pixel data. Since the number of band descriptors BAD is, for example, thousands, it is considerably larger than the number of block descriptors BLD (for example, 10 to several tens). Therefore, according to the present embodiment, the access time to the data of the nth pixel can be shortened compared with the case where the block descriptor BLD is not used.

1 Image Processing Device 31 Storage Unit (Example of Block Descriptor Storage Unit)
BL, BL1 to BL16 Block area BA, BA1, BA2, BA21, BA22 Band area BLD, BLD1 to BLD16 Block descriptor BAD, BAD1 to BAD3, BAD21 to BAD23 Band descriptor P First pixel M22 of block area BL5 Band area data m1 m5 divided data Q 700,000th pixel

Claims (4)

Main memory,
A block area that is assigned to each of a plurality of block areas arranged in the main scanning direction and the sub-scanning direction, and is information on the number of pixels in the main scanning direction and the sub-scanning direction and the coordinates of the leading pixel for the assigned block area A block descriptor processing unit for processing a plurality of block descriptors including information in advance;
A band-shaped band area with a larger number of pixels in the main scanning direction and a smaller number of pixels in the sub-scanning direction than the block area, and processes a plurality of band descriptors assigned to each of the plurality of band areas arranged in the sub-scanning direction A band descriptor processing unit,
A processing unit that processes the image data stored in the main memory by dividing it into a plurality of band area data corresponding to each of the plurality of band areas, and dividing the band area data into a plurality of divided data. A division processing unit that executes processing for storing the different addresses in the main memory for each of the plurality of band area data,
The band descriptor processing unit, when the image data is stored in the main memory, with respect to a band descriptor assigned to the band area corresponding to the band area data, In each of the plurality of band descriptors, a process of adding pixel data data address information on the main memory and divided data information that is information on the number of pixels of each of the plurality of divided data to be stored in the main memory is performed in each of the plurality of band descriptors. Run,
The plurality of band descriptors are ordered, and each of the plurality of band descriptors stored in the main memory includes address information on the main memory of a band descriptor in the next order,
When the image data is stored in the main memory, the block descriptor processing unit assigns an address on the main memory of a band descriptor assigned to the band area including the first pixel of the block area. An image processing apparatus that executes a process of storing, in the main memory, a block descriptor including information on the band descriptor association address in each of the plurality of block descriptors. The plurality of block descriptors are ordered and an address on the main memory is assigned in advance for each of the plurality of block descriptors, and information on the address on the main memory of the next block descriptor, A block descriptor storage unit in which the plurality of block descriptors including the block area information and the information of the band descriptor association address are stored in advance;
The block descriptor processing unit reads out the plurality of block descriptors stored in the block descriptor storage unit and stores them in the main memory when the image data is stored in the main memory. Image processing apparatus. With respect to an image formed based on the image data stored in the main memory, coordinates in the main scanning direction and the sub-scanning direction in which the nth pixel (n is a positive integer) is located are used as the main scanning of the image. A coordinate calculation unit that calculates based on the number of pixels in the direction;
A block descriptor reading unit for reading the plurality of block descriptors stored in the main memory;
Based on the coordinates of the n-th pixel calculated by the coordinate calculation unit and the block region information included in each of the plurality of block descriptors read by the block descriptor reading unit, A block region specifying unit for specifying a block region to which the nth pixel belongs,
A band descriptor reading unit that reads out, from the main memory, a band descriptor stored in the band descriptor association address included in the block descriptor for the block descriptor assigned to the block region specified by the block region specifying unit; The image processing apparatus according to claim 1, further comprising: The band to which the nth pixel belongs among the plurality of band regions, based on the number of pixels in the subscanning direction of the band region and the coordinates of the nth pixel calculated in the coordinate calculation unit. A band region specifying unit that specifies a region and a position in the sub-scanning direction of the n-th pixel in the band region;
The coordinates in the main scanning direction of the nth pixel calculated by the coordinate calculation unit, the position in the sub-scanning direction of the nth pixel specified by the band area specifying unit, and the pixel in the main scanning direction of the image data A pixel number calculation unit that calculates the number of pixels from the first pixel of the band region to which the nth pixel specified by the band region specifying unit belongs to the nth pixel, based on the number;
Based on the divided data information included in the band descriptor read by the band descriptor reading unit and the number of pixels calculated by the pixel number calculating unit, the data of the nth pixel among the plurality of divided data is A divided data specifying unit for specifying the divided data to which it belongs;
Based on the number of pixels calculated by the pixel number calculation unit, the main memory of the nth pixel data from the address on the main memory of the data of the first pixel of the divided data specified by the divided data specifying unit The image processing apparatus according to claim 3, further comprising: an address specifying unit that specifies an upper address.

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