JP2011076197A - Apparatus and method for processing image, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an amount of data while maintaining high quality of image data. <P>SOLUTION: An image processing apparatus 200 includes a resolution determining part 222 for determining a plurality of divide resolutions used for dividing an image, and a data generating part 223 for generating multi-resolution data indicating the image by using a plurality of kinds of blocks (501 to 551) corresponding to the plurality of divide resolutions. The resolution determining part determines a minimum divide resolution based on a greatest common divisor of the number of pixels in the longitudinal and lateral directions of the image and determines a plurality of divide resolutions to have a value obtained by multiplying the minimum divide resolution by an integer. The data generating part 223 divides the image into a plurality of uniform blocks (A1 to Fn) by using blocks as large as possible among the plurality of kinds of blocks, and generates multi-resolution image data including a resolution number indicating the resolution of respective uniform blocks obtained by the block division, and color information of the blocks. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for reducing the amount of image data.

  When transferring a high-resolution image between image processing apparatuses such as a printer, a personal computer, or a digital still camera, the processing load for image transfer increases because of the large amount of data to be processed. Accordingly, the amount of transferred data is reduced by compressing and transferring an image or transferring the image with a reduced resolution. Here, when the image including the character part and the other part (hereinafter referred to as “picture part”) is transferred with the resolution reduced uniformly, the line width in the character part of the expanded image is not reduced. Degradation of image quality such as uniformity and shaggy can occur. Therefore, a method has been proposed in which a character part and a picture part are separated, transferred to respective appropriate resolutions, and combined on the receiving side after increasing the resolution of each part to match the resolution. (For example, Patent Documents 1 and 2).

JP 2001-136374 A JP 2002-176552 A

  However, in the conventional method, there is a problem that the processing load such as image synthesis on the receiving side is heavy. In particular, when image data for printing is sent from a computer to a printer, there is a problem that it takes a long processing time as a whole system if arithmetic processing such as image synthesis is performed with a printer having a processing capability smaller than that of a computer.

  An object of the present invention is to solve at least a part of the above-described problems and to reduce the amount of data while maintaining high quality for image data.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
An image processing apparatus, a resolution determination unit for determining a plurality of division resolutions used when dividing an image, and multi-resolution image data representing the image using a plurality of types of blocks corresponding to the plurality of division resolutions And a data generation unit for generating the resolution, and the resolution determination unit determines a minimum divided resolution of the plurality of divided resolutions based on a greatest common divisor of a vertical length and a horizontal length of the image. Determining the plurality of division resolutions so as to have a relationship obtained by sequentially multiplying the minimum division resolution by an integer, and the data generation unit uses the largest possible block among the plurality of types of blocks. The image is divided into a plurality of uniform blocks, and a multi-resolution including a resolution number indicating the resolution of each uniform block obtained by the block division and color information of the block Generating the image data, the image processing apparatus.
According to this application example, the image is divided into as large blocks as possible based on the greatest common divisor of the number of pixels in the vertical direction and the number of pixels in the horizontal direction. Then, multi-resolution image data including a resolution number indicating a block division resolution for each uniform block and block color information is generated. Therefore, it is possible to reduce the data amount of image data while maintaining high quality.

[Application Example 2]
In the image processing apparatus according to Application Example 1, in the process of generating the multi-resolution data, the image data generation unit sets (a) a lowest divided resolution among the plurality of divided resolutions as a set divided resolution. In addition, the entire image is set as a division target image area, (b) the division target image area is divided into a plurality of blocks at the set resolution, and (c) among the plurality of divided blocks. One block is sequentially selected as a processing target block, (d) it is determined whether or not the processing target block is uniform, and (d-1) when the processing target block is uniform, the set division resolution And the color information indicating the color of the processing target block are generated as multi-resolution image data representing the processing target block, and the processing returns to the processing (c). (D-2) When the processing target block is not uniform, (d-2-1) the next highest division resolution after the set division resolution is the plurality of divisions. When the resolution is equal to or lower than the highest division resolution, the next highest division resolution is set as a new set division resolution, the processing target block is set as a new division target image area, and the processing ( Returning to b), the processing after the processing (b) is executed, and (d-2-2) the next highest division resolution of the set division resolution exceeds the highest division resolution among the plurality of division resolutions Includes generating resolution information indicating the set division resolution and color information indicating the color of the processing target block as multi-resolution image data representing the processing target block, and (e) performing the processing (c). When the next block among the plurality of blocks having the set division resolution does not exist and when the process (d-2-2) is performed, the set division resolution is set to the next lowest. An image processing apparatus that sets the division resolution and returns to the processing (c) to execute the processing after the processing (c).

[Application Example 3]
In the image processing apparatus according to Application Example 2, the ratio between the set divided resolution in the process (d-2-1) and the next highest divided resolution is a constant ratio regardless of the size of the set divided resolution. An image processing apparatus.
According to this application example, the set divided resolution and the next highest divided resolution and the ratio are constant regardless of the size of the set divided resolution, so that the processing is not complicated.

[Application Example 4]
In the image processing apparatus according to Application Example 3, the ratio between the set division resolution in the process (d-2-1) and the division resolution having the next lowest division resolution is 2, and the process returns to the process (b). The image data generation unit divides the block into 2 × 2 4 blocks.
According to this application example, it is possible to make the next block as large as possible.

  The present invention can be realized in various forms. For example, in addition to an image processing apparatus, the present invention can be realized in various forms such as an image processing method and a computer program.

It is explanatory drawing which shows schematic structure of the image transfer system in 1st Example of this invention. It is explanatory drawing which shows the detailed structure of the image transfer system 400 shown in FIG. It is explanatory drawing which shows typically the principle which produces the image data for transfer from raster image data. It is explanatory drawing which shows the relationship between the block formed by dividing | segmenting raster image data, and division | segmentation resolution. It is explanatory drawing which shows the production | generation flow of image data. It is explanatory drawing explaining the content of the process of FIG. 5 using an image. It is explanatory drawing explaining the content of the process of FIG. 5 using an image. It is explanatory drawing which shows a part of produced | generated image data for transfer. It is a part of explanatory drawing which shows each block when a certain image is divided into blocks, and the resolution number of the block. It is explanatory drawing which shows an example of the method for determining whether a block is uniform. It is explanatory drawing which shows a mode when an image is decompress | restored using the image data for transfer shown in FIG. It is explanatory drawing which shows a mode when an image is decompress | restored using the image data for transfer shown in FIG. It is explanatory drawing explaining the content of the division | segmentation process when an image component is shown by vector data using an image. It is explanatory drawing explaining the content of the division | segmentation process when an image component is shown by vector data using an image. It is explanatory drawing which shows an example of the method for determining whether a block when an image component is shown by vector data is uniform. It is explanatory drawing which shows a 3rd Example. It is explanatory drawing which shows a 4th Example. It is explanatory drawing which shows the modification of a 4th Example. It is explanatory drawing which shows a 5th Example. It is explanatory drawing which shows a 6th Example.

Hereinafter, the best mode for carrying out the present invention will be described based on examples.
A. First embodiment:
A1. System configuration:
FIG. 1 is an explanatory diagram showing a schematic configuration of an image transfer system according to the first embodiment of the present invention. The image transfer system 400 includes a multifunction peripheral 100 and a personal computer 200. The multifunction device 100 and the personal computer 200 are connected to each other via a cable 150. As a connection interface between the MFP 100 and the personal computer 200, for example, a USB (Universal Serial Bus) interface or a LAN (Local Area Network) interface such as IEEE 802.3 can be employed. Instead of wired connection using a cable, wireless connection such as IEEE802.11b standard wireless LAN connection or IrDA (Infrared Data Association) standard infrared connection may be employed.

  The multifunction device 100 functions as a printer, a scanner, and a copying apparatus. In the image transfer system 400, image data can be transferred from the personal computer 200, and an image can be printed in the multifunction peripheral 100.

  FIG. 2 is an explanatory diagram showing a detailed configuration of the image transfer system 400 shown in FIG. The personal computer 200 includes a computer main body 201, a display device 202, a keyboard 203, and a mouse 204. The computer main body 201 includes a CPU 20, a memory 31, a hard disk 32, an I / O control unit 33, and a network interface unit 34.

  The memory 31 stores an application program that handles images, and the CPU 20 functions as the application execution unit 21 by executing the application program. As an application for handling images, for example, an image browsing application (such as Acrobat Reader (registered trademark) of Adobe Systems) or retouch software can be employed. The memory 31 also stores device driver programs (printer driver program and scanner driver program) for the multifunction machine 100. The CPU 20 functions as the printer driver 22 by executing a printer driver program. The printer driver 22 includes a raster data expansion unit 221, a data conversion unit 222, and a data transmission control unit 225.

The application execution unit 21 displays and processes an image according to a user instruction. The raster data development unit 221 interprets the drawing data generated by the application execution unit 21 and develops it into raster image data. The drawing data is a representation of a plurality of image parts (for example, characters, figures, and patterns) constituting an image by vector data and bitmap data. Typically, characters and figures are represented by vector data, and patterns (photos and the like) are represented by bitmap data. The raster image data is a bitmap image, and each pixel has, for example, R (red), G (green), and B (blue) gradation values (8 bits × 3 channels). Note that the application execution unit 21 may directly generate raster image data. For example, when the application execution unit 21 processes an image captured by a digital camera, the application execution unit 21 directly generates raster image data. The data converter 222 converts (compresses) the raster image data into transfer image data with a smaller data amount. It is also possible to employ a configuration in which the data converter 222 directly converts drawing data into image data for transfer without going through a raster image, which will be described later. The data transmission control unit 225 converts the transfer image data into a data format corresponding to the connection interface between the multifunction peripheral 100 and the personal computer 200, and performs error control, flow control, and the like during data transmission. Note that the data conversion unit 222 includes a division resolution determination unit 223 that determines a division resolution for dividing a block, and a determination unit 224 that determines whether or not the block of the region of interest is uniform.

  The I / O control unit 33 includes an interface group for connecting the display device 202, the keyboard 203, and the mouse 204 to the computer main body 201. The I / O control unit 33 controls transmission of display screen data to the display device 202 and reception of input information from the keyboard 203 and the mouse 204. The network interface unit 34 includes a group of connection interfaces with the multifunction peripheral 100.

  The multifunction device 100 includes a control circuit 10, a printer engine 13, a reading unit 14, an operation unit 15, a display unit 16, and a network interface unit 17. The control circuit 10 includes a memory 11 and a CPU 12. The memory 11 stores a control program for the multifunction peripheral 100, and the CPU 12 executes the control program so that the data reception control unit 12a, the image data decompression unit 12b, the color conversion unit 12c, and the halftone. It functions as a processing unit 12d and a data rearrangement unit 12e.

  The data reception control unit 12 a receives transfer image data transmitted from the personal computer 200. The image data decompression unit 12b decompresses the transfer image data and generates raster image data. The color conversion unit 12c converts the raster image data (R, G, B) into gradations of ink colors (cyan (C), magenta (M), yellow (Y), black (K)) used in the printer engine 13. Convert to image data consisting of values (color conversion). The color conversion unit 12c performs the above-described color conversion with reference to a color conversion table (not shown) that is a three-dimensional lookup table stored in the memory 11. The halftone processing unit 12d converts the image data after color conversion into print data by performing halftone processing. This print data is represented by dot ON / OFF for each color (C, M, Y, K). The data rearrangement unit 12e rearranges the print data obtained by the halftone process into a data format associated with an ink head, a nozzle number, or the like in the printer engine 13.

  The printer engine 13 is an ink jet printing mechanism including a print head (not shown), and prints an image or the like on a print sheet by feeding paper, scanning the print head, discharging ink, or the like. The reading unit 14 is a so-called flat bed type (original fixed type) scanner that reads an original fixed while an image sensor (not shown) moves. The operation unit 15 includes various operation buttons and accepts an operation input by a user. The display unit 16 displays an operation menu screen, an error message, and the like.

  In the image transfer system 400 having the above-described configuration, the quality of the print image is reduced while executing the transfer image data generation process described later, thereby reducing the data amount of the transfer image data transferred from the personal computer 200 to the multifunction peripheral 100. It is comprised so that the fall of may be suppressed.

A2. Image data transmission processing:
When a user executes an application that handles images on the personal computer 200 and wants to print an image displayed on the display device 202, the user selects a print execution menu (not shown) from the menu screen of the application. At this time, the user can display the setting screen for the printer driver on the display device 202, and can specify the printing device to be used and set the print quality.

  Upon receiving a print instruction from the user, the application execution unit 21 (FIG. 2) generates drawing data according to the print instruction. The raster data developing unit 221 interprets the drawing data and develops it into raster image data including color information (R, G, B) for each pixel. The data conversion unit 222 executes transfer image data generation processing, which will be described later, and converts (compresses) raster image data into transfer image data. The data transmission control unit 225 converts the transfer image data into a data format corresponding to the connection interface between the multifunction device 100 and the personal computer 200 and transmits the data format to the multifunction device 100 via the network interface unit 34.

A3. Image data compression processing:
FIG. 3 is an explanatory diagram schematically showing the principle of creating transfer image data from raster image data. FIG. 3A shows an example of raster image data 500 before conversion, in which the letter “A” is displayed in black on a white background. In the example shown in FIG. 3A, raster image data 500 is formed by collecting a plurality of pixels each having a size of 2400 dpi × 2400 dpi. In FIG. 3A, the entire image is drawn as being divided into 4 × 4, but the line of this division does not actually exist, and is drawn for convenience of illustration only. .

  FIG. 3B shows raster image data 500a (multi-resolution image data) after conversion. In data conversion, a plurality of types of blocks R0 to R5 having different sizes are used. That is, the data conversion unit 222 divides the raster image data 500 into a plurality of uniform blocks using the largest possible block among the plurality of types of blocks R0 to R5. In the example shown in FIG. 3B, the largest block is the block R0 (divided resolution 75 dpi × 75 dpi). First, the data converter 222 divides the raster image data 500 in this block R0. Then, it is determined whether each block is uniform. If the divided blocks are not uniform, the block is divided into the next largest block R1 (divided resolution 150 dpi × 150 dpi). In this way, division is performed in order of blocks having a large division resolution. The resolution of the block R5 having the highest resolution divided by this procedure is the same as the resolution of the original raster image data 500 (2400 dpi × 2400 dpi). Although FIG. 3B is drawn larger than FIG. 3A, the actual dimensions of both images are the same.

  FIG. 4 is an explanatory diagram showing a relationship between blocks used for dividing raster image data and division resolution. FIG. 4A shows the entire raster image data 500 shown in FIG. The raster image data 500 is divided into 16 blocks 501 (blocks A0 to A16). Here, the division resolution of each block 501 is 75 dpi × 75 dpi. Here, the division resolution of a block is (N) dpi × (N) dpi means that the size of the block or the distance between the centers of adjacent blocks is 1 / N inch. The block 501 is the largest block for dividing the raster image data 500. Here, the resolution number of the block 501 is “0” (hereinafter also referred to as “R (0)”).

  FIG. 4B shows a state in which the block 501 in FIG. 4A is further divided into 2 × 2 4 blocks. That is, the block 501 has four blocks 511. The division resolution of the block 511 is 150 dpi × 150 dpi. This block 511 is the next largest block after the block 501, and its resolution number is R (1). Hereinafter, FIGS. 4C to 4F show a state in which the blocks shown in FIGS. 4B to 4E are similarly divided into 2 × 2 4 blocks. The division resolutions of the blocks 521, 531, 541, and 551 shown in FIGS. 4C to 4F are 300 dpi, 600 dpi, 1200 dpi, and 2400 dpi, respectively. In addition, the resolution numbers of the blocks 521, 531, 541, and 551 are R (2), R (3), R (4), and R (5), respectively. The division resolution 2400 dpi of the block 551 matches the highest printing resolution of the multifunction peripheral 100 (FIG. 1).

  Note that the number (number of types) of blocks used for division is preferably 3 or more. Moreover, it is preferable that the resolutions of a plurality of types of blocks have a relationship of sequentially multiplying by an integer. In the example of FIG. 4, the resolutions of the five types of blocks 501 to 551 are in a relationship of sequentially multiplying by 2.

  FIG. 5 is an explanatory diagram showing a generation flow of image data. In step S500, the data conversion unit 222 acquires the print resolution of the multifunction peripheral 100. In this embodiment, the maximum printing resolution of the multifunction peripheral 100 is 2400 dpi, and this maximum printing resolution is used as the highest division resolution of the transfer image data. Note that the value of the highest division resolution of the transfer image data is not limited to the highest print resolution of the multifunction peripheral 100, and the print resolution in any print mode of the multifunction peripheral 100 can be employed.

  In step S505, the division resolution determination unit 223 sets a minimum division resolution (Rmin) and a maximum division resolution (Rmax) when dividing raster image data. The division resolution determination unit 223 first uses the print resolution acquired from the multifunction peripheral 100 as the highest division resolution Rmax. In this embodiment, the maximum division resolution Rmax is 2400 dpi. Next, the division resolution determination unit 223 determines a plurality of division resolutions for dividing the transfer image data by repeatedly halving the value of 2400 dpi. Specifically, 2400 dpi is reduced to half of 1200 dpi, and 1200 dpi is decreased to half of 600 dpi. The division resolution determination unit 223 repeats this to finally lower the resolution to 75 dpi. Note that the division resolution determination unit 223 can arbitrarily determine how much the division resolution is to be lowered. For example, the number of times of halving may be determined in advance, for example, 5 times or 6 times. Further, the divided resolution determination unit 223 may determine the size of the divided resolution in advance. For example, the divided resolution determination unit 223 may be configured not to create a lower divided resolution when the divided resolution becomes less than 100 dpi. In this embodiment, the division resolution determination unit 223 sets the resolution of 75 dpi, which is the first division resolution when the division resolution is less than 100 dpi, as the lowest division resolution. This lowest division resolution is set as the lowest division resolution Rmin of the transfer image data. As described above, the division resolution determination unit 223 acquires a plurality of division resolutions for dividing an image using the print resolution value obtained from the multifunction peripheral 100. Next, the data conversion unit 222 assigns a resolution number to each divided resolution. The data conversion unit 222 sets the resolution number of the lowest divided resolution to R (0), and increases the value of the resolution number by 1 as the resolution is doubled. If the resolution number of resolution 75 dpi is R (0), the resolution number of 2400 dpi which is the highest division resolution is R (5).

  In step S510, the printer driver 22 (FIG. 2) acquires an image to be output to the multifunction peripheral 100 (FIG. 1) from the running application. This image is first output as drawing data by the application execution unit 21. Next, the raster data development unit 221 converts the drawing data into raster image data. At this time, raster image data is developed with the highest division resolution.

  In step S515, the data conversion unit 222 sets the set division resolution to the minimum division resolution Rmin. That is, the set division resolution is R (0) (= 75 dpi).

  6 and 7 are explanatory diagrams for explaining the contents of the processing of FIG. 5 using images. FIG. 8 is an explanatory diagram showing a part of the generated transfer image data. The transfer image data corresponds to the multi-resolution image data in the claims. In step S520 of FIG. 5, the data conversion unit 222 divides the image with the set division resolution R (0) (= 75 dpi). FIG. 6A shows a state in which the data conversion unit 222 divides an image into 4 × 4 16 blocks (blocks A1 to A16) with a set division resolution R (0) (= 75 dpi).

  In step S525 of FIG. 5, the data conversion unit 222 sets the upper left block A1 as a region of interest. The image before division is a rectangle, and the blocks after division are arranged vertically and horizontally in the rectangle. In the next step S530, the data converter 222 determines whether or not the block A1 that is the region of interest is uniform. If the block A1 is an area filled with one color (white, black, or any color), the block A1 is uniform. A method for determining whether or not it is uniform will be described later. This determination process is executed by the determination unit 224.

  If the block A1, which is the region of interest, is uniform, in step S550, the data conversion unit 222 stores the resolution number and color information of the block A1 in the transfer image data. In this embodiment, the block A1 is uniform and the color is “white”. Therefore, the data converter 222 adds the resolution number and RGB data (R (n), R, G, B) = (0, 00h, 00h, 00h)) to the data on the Da1 line of the transfer image data in FIG. Is stored. Note that “h” at the end of the RGB data indicates a hexadecimal number.

  The data conversion unit 222 shifts the processing to steps S555 and S560, and sets the next block as a region of interest. Since the current region of interest is the block A1, the data conversion unit 222 sets the block A2 as the region of interest. In a specific method of moving the attention area, when there is a new block on the right side of the block that is the current attention area, the data conversion unit 222 sets the right block as the new attention area. When the region of interest is the block A1, there is a block A2 on the right side of the block A1. Therefore, the data converter 222 moves the region of interest to the block A2. On the other hand, when there is no new block on the right side of the block that is the current region of interest, the data converter 222 sets the leftmost block among the lower blocks as the region of interest. For example, when the current region of interest is the block A4, there is no new block on the right side of the block A4. Accordingly, the data conversion unit 222 sets the block A5, which is the leftmost block among the lower blocks, as a region of interest. Note that the case where there is no block on either the right side or the lower side of the block that is the current region of interest (step S560, No) will be described later. If a new region of interest exists, the CPU 20 proceeds to the process of step S530.

  In step S530, the data conversion unit 222 determines whether or not the block A2 that is a new region of interest is uniform. In the present embodiment, since the block A2 has a colored portion in the lower right portion, the determination result is “block A2 is not uniform”. Next, in step S535, the data conversion unit 222 determines whether or not the current set division resolution R (i) is the highest division resolution Rmax. Since the current set division resolution R (i) is R (0) (= 75 dpi) and not the highest division resolution Rmax (= 2400 dpi), the data conversion unit 222 sets one set division resolution in step S540. Increase the setting division resolution to 150dp. In step S545, the CPU divides the block A2 with the new setting division resolution R (1) (= 150 dpi). Thereby, as shown in FIG. 6B, the block A2 is divided into four blocks B1 to B4.

  The data conversion unit 222 moves the process to step S525, and similarly sets the upper left block B1 as a region of interest. In step S530, the data conversion unit 222 determines whether or not the block B1 that is the region of interest is uniform. In this embodiment, since the block B1 is uniform and white, the data converter 222 shifts the processing to step S550, and the resolution number and RGB data are added to the Da2 line data of the transfer image data in FIG. (R (n), R, G, B) = (1, 00h, 00h, 00h)) is stored. Hereinafter, in step S555 of FIG. 5, the data conversion unit 222 sequentially moves the block B2, B3, and B4 and the region of interest, and performs the same processing. In this embodiment, since the blocks B2 and B3 are both uniform and white, the data conversion unit 222 adds the resolution number and RGB data (R (n)) to the Da3 and Da4 line data of the transfer image data. , R, G, B) = (1,0h, 00h, 00h)). Here, the resolution number of the divided resolution 150 dpi is R (1).

  Block B4 is not uniform. In step S535, the data conversion unit 222 determines whether or not the current set division resolution R (1) (= 150 dpi) is the highest division resolution Rmax (= 2400 dpi). Since the current set division resolution R (1) (= 150 dpi) is not the highest division resolution Rmax (= 2400 dpi), the data conversion unit 222 increases the setting division resolution by one to double it to 300 dpi in step S540. . In step S545, the data conversion unit 222 divides the block B4 with the set division resolution R (2) (= 300 dpi). Specifically, as shown in FIG. 6C, the CPU 20 divides the block B4 into four blocks C1 to C4.

  Hereinafter, similarly, the CPU 20 determines whether or not the blocks C1 to C4 are uniform in order (step S530). Since the blocks C1 and C2 are uniform, the data conversion unit 222 executes steps S550 to S560, and the resolution number and RGB data (R (n)) are added to the Da5 and Da6 lines of the transfer image data. , R, G, B) = (2, 00h, 00h, 00h)). On the other hand, since the blocks C3 and C4 are not uniform, steps S535 to S545 and steps S525 and S530 are executed for each of the blocks C3 and C4, respectively.

  In step S540, as shown in FIG. 6D, the data converter 222 converts the block C3 into blocks D1 to D1 with a set division resolution R (3) (= 600 dpi) obtained by increasing the set resolution R (i) by one. It is divided into four blocks of D4, and it is determined whether or not they are uniform in order (step S530). Since the blocks D1 to D3 are uniform, the data conversion unit 222 sequentially executes steps S530 and S550 for the blocks D1 to D3, respectively, and sets the resolution number and the data in the Da7 to Da9 lines of the transfer image data. RGB data (R (n), R, G, B) = (3, 00h, 00h, 00h)) is stored. Since the block D4 is not uniform, steps S535 to S545 and steps S525 and S530 are executed.

  In step S540, as shown in FIG. 6E, the data conversion unit 222 converts the block D4 into blocks E1 to E1 with a set division resolution R (4) (= 1200 dpi) obtained by increasing the set resolution R (i) by one. The block is divided into four blocks E4, and it is determined whether or not the blocks are uniform in order (step S530). Here, the blocks E1 and E3 are uniform, but the blocks E2 and E4 are not uniform. The data converter 222 executes Steps S530 and S550 for the block E1, and the resolution number and the RGB data (R (n), (R, G, B)) = ( 4,000h, 00h, 00h)). Since the block E2 is not uniform, steps S535 to S545 and steps S525 and S530 are executed.

  In step S540, the data conversion unit 222 blocks the block E2 at the set division resolution R (5) (= 2400 dpi) obtained by increasing the set resolution R (i) by one as shown in FIG. 7 (F-1). Divide into four blocks F1 to F4. Here, the sizes of the blocks F1 to F4 are equal to the size of one pixel of the raster image data generated by the raster data development unit 221. Since one pixel of raster image data generated by the raster data development unit 221 is one color, the blocks F1 to F4 are uniform. The data conversion unit 222 executes steps S530 and S550 for the blocks F1 to F4, and stores the resolution number and RGB data in the data on the Da11 line to the Da14 line of the transfer image data. The RGB data from the Da11 line to the Da14 line are, for example, (R (n), R, G, B) = (5,000h, 00h, 00h)), (R (n), R, G, B) = (5,33h, 33h, 33h)), (R (n), R, G, B) = (5,00h, 00h, 00h)), (R (n), R, G, B) = ( 5, 4Bh, 4Bh, 4Bh)). If the set division resolution R (i) is the highest division resolution Rmax, the region of interest is uniform in step S530. Therefore, the data conversion unit 222 moves the process to step S550 and does not execute steps S535 to S545.

  In step S560, the data conversion unit 222 determines whether the next block having the same set division resolution R (5) (2400 dpi) exists in the block E2 after the block F4. Since this block does not exist, in step S565, the data conversion unit 222 determines whether or not the current set division resolution R (i) is the lowest division resolution Rmin. Here, since the current set division resolution R (5) (= 2400 dpi) is not the lowest division resolution Rmin (= 75 dpi), the data conversion unit 222 shifts the processing to step S570, and sets one set division resolution. Return to R (4) (= 1200 dpi). In step S555, the data conversion unit 222 moves the region of interest to the block E3 from the block E2 including the block F4 of interest (see FIG. 6E). Since the block E3 is uniform, the data conversion unit 222 executes steps S530 and S550 for the block E3, and adds the resolution number and RGB data (R (n), R) to the Da15 data of the transfer image data. , G, B) = (4, 00h, 00h, 00h)). Then, the data conversion unit 222 moves the region of interest to the block E4.

  Since the block E4 is not uniform like the block E2, the data conversion unit 222 performs the same processing as the block E2 on the block E4. The data converter 222 divides the block E4 at the set division resolution R (5) (= 2400 dpi) in the same manner as when the block E2 is divided (step S545), and obtains four blocks F5 to F8. For the blocks F5 to F8, the data conversion unit 222 stores the resolution number and the RGB data in the transfer image data as in the blocks F1 to F4 (step S550). Specifically, these data are stored in lines Da16 to Da20 of the transfer image data in FIG. FIG. 7F-2 shows a state in which the block E4 in FIG. 6E is cut at a resolution of 2400 dpi.

  Since there is no block next to the same setting division resolution R (5) of the block F8, the CPU 20 returns the setting division resolution R (5) to the setting division resolution R (4) (= 1200 dpi) in step S570. The region of interest at this point is the block E4 (FIG. 6E). Even in the setting division resolution R (4) (= 1200 dpi), there is no next block of the same setting division resolution R (4). Therefore, in step S570, the CPU 20 sets the setting division resolution R (4) to the setting division resolution R. (3) Return to (= 600 dpi). The region of interest at this point is the block D4 (FIG. 6D). Even at this set division resolution R (3) (= 600 dpi), there is no next block of the same set division resolution R (3), so the CPU 20 sets the set division resolution R (3) to the set division resolution in step S570. Return to R (2) (= 300 dpi). The region of interest at this point is the block C3 (FIG. 6C). Here, the block C4 which becomes the next attention area exists. Therefore, the CPU 20 performs the same process with the block C4 as the region of interest. The CPU 20 stores the resolution information and RGB data obtained by this processing in the transfer image data of FIG. Specifically, the rows in which these data are stored are Da20 to Da32 rows.

  Since there is no block next to the same setting division resolution R (2) of the block C4, the CPU 20 returns the setting division resolution R (2) to the setting division resolution R (1) (= 150 dpi) in step S570. At this time, the region of interest is the block B4 (FIG. 6B). Even in the set division resolution R (1) (= 150 dpi), there is no next block having the same resolution, and therefore the CPU 20 sets the set division resolution R (1) to the set division resolution R (0) (= Return to 75 dpi). The region of interest at this point is the block A2 (FIG. 6A). Here, there is a block A3 that becomes the next region of interest. Therefore, the CPU 20 performs the same processing with the block A3 as the region of interest. The CPU 20 stores the resolution information and RGB data obtained by this processing in the transfer image data of FIG. Specifically, these data are stored after the transfer image data Da33 line. In FIG. 8, only a part of the transfer image data (up to the Da37 line) is shown for the sake of space.

  Thereafter, the same processing is repeated until the final block A16 in the image (FIG. 6A) becomes the region of interest. If the region of interest is block A16 and an attempt is made to move the region of interest in step S555, there is no next region of interest (step S560), and the current set division resolution R (i) is 75 dpi of the minimum resolution Rmin ( Step S565), the process is terminated.

  FIG. 9 is a part of an explanatory diagram showing each block and a resolution number of the block when an image is divided into blocks. The image is the same as the image used in FIGS. 5 to 8, but only a part of the image is shown in FIG. FIG. 9 shows a state in which an image is divided using as large a block as possible first, and then sequentially using smaller blocks. Here, the numbers “0” to “4” in each block are the numbers “n” of the resolution number “R (n)”. It is. Note that a block obtained by dividing a block with the resolution number “4” into four (a block corresponding to the resolution number R (5)) is not described with “5” abbreviating the resolution number. This is because the resolution number is not shown in FIG. 9 because the characters are thin and difficult to see. In addition, in FIG. 9, a block having a resolution number of 3 or less (large block) is associated with the Dan row in FIG. 8 (n is up to 37 in accordance with FIG. 8), and which block corresponds to which row of data. It describes what to do.

  FIG. 10 is an explanatory diagram illustrating an example of a method for determining whether or not a block is uniform. The block has a plurality of pixels P1 to Pn. The size of the pixels P1 to Pn is the same size as one pixel of the raster image data 500 (see FIG. 3A). First, the RGB data of the pixel P1 and the RGB data of the pixel P2 are compared, then the pixel P1 and the pixel P3 are compared, and the pixel P1 and the pixel Pn are sequentially compared. In any comparison, when there is a pixel Px (x is an integer between 2 and n) whose RGB data is different from the RGB data of the pixel P1, the determination unit 224 determines that the block has a plurality of colors. The data conversion unit 222 increases the setting division resolution. If the determination unit 224 finds that there is a pixel Px whose RGB data is different from that of the pixel P1, the determination unit 224 may stop comparing the RGB data for the subsequent pixels in the block.

A4. Restoration process:
FIG. 11 and FIG. 12 are explanatory diagrams showing a state when an image is restored using the transfer image data shown in FIG. The restoration process is executed by the image data decompression unit 12b. In FIG. 11A, the image data decompression unit 12b creates a frame 600 for the entire image. The raster image data having vertical and horizontal sizes is included in a part of the transfer image data (not shown). Then, the image data decompression unit 12b generates the frame 600 using the vertical and horizontal sizes of the image. Next, the image data decompression unit 12b reads the data from the Da1 line of the transfer image data (FIG. 8), restores each resolution number from the RGB data to the block Dbn, and arranges it in the frame 600. . First, the image data decompression unit 12b divides the frame 600 with a division resolution corresponding to the resolution number R (0) to generate blocks A1 to A16. The image data decompression unit 12b stores the resolution number at this time in the memory 11 as the restoration resolution number S (0), for example.

  FIG. 11B shows a state in which the image data decompression unit 12b restores the block Db1 using the data on the Da1 line of the transfer image data (FIG. 8) and arranges it at the position of the block A1. The image data decompression unit 12b first restores the block Db1 using the data in the Da1 row. Next, the image data decompression unit 12b compares the sizes of the block Db1 and the block A1. This comparison can be easily determined by comparing the resolution number R (0) on the Da1 line of the transfer image data with the restored resolution number S (0). In this embodiment, the resolution number R (0) and the restored resolution number S (0) are the same. Therefore, the block Db1 is arranged at the position of the block A1. In the above processing, the image data decompression unit 12b reads the data on the first line of Da from the transfer image data, restores the block Db1 having a size corresponding to the resolution number, and the size of the block A1 based on the resolution number. If they are the same, they are only placed at the position of the block A1, so the burden of data processing is extremely small. Hereinafter, the divided blocks are denoted by codes such as A1 to A16 and B1 to B4, and these codes are matched with the codes used for the blocks used in FIGS.

  FIG. 11C shows a state in which the image data decompression unit 12b restores and arranges the blocks Db2 to Db4 using the data in the Da2 to Da4 rows of the transfer image data (FIG. 8). First, the image data decompression unit 12b reads Da2 line data from the transfer image data and restores the block Db2. The image data decompression unit 12b tries to arrange the block Db2 at the position of the block A2. However, the resolution number R (1) of the block Db2 is one larger than the restoration resolution number S (0) of the block A2. As a result, the size of the block Db2 is ¼ the size of the block A2, and the size of the block Db2 does not match the size of the block A2. In such a case, the image data decompression unit 12bCPU 12 divides the block A2 into 2 × 2 and creates four blocks B1 to B4 having the restoration resolution number S (1) (see FIG. 6B). The sizes of the blocks B1 to B4 are the same as the size of the block Db2. Then, the image data decompression unit 12b arranges the block Db2 at the position of the block B1 (2 × 2 upper left portion). The image data decompression unit 12b easily determines whether or not the block sizes match by comparing the restoration resolution number S (i) and the resolution number R (i) of the transfer image data. It is possible.

  The image data decompression unit 12b reads the data on the Da3 line from the transfer image data, and restores the block Db3. The block Db3 has the same resolution number R (1) as the restored resolution number S (1) of the block B2, and the size of the block Db3 is the same as the size of the block B2. The image data decompression unit 12b arranges the block Db3 at the position of the block B2 (2 × 2 upper right part).

  The image data decompression unit 12b reads Da4 line data from the transfer image data and restores the block Db4. The block Db4 has the same resolution number R (1) as the restored resolution number S (1) of the block B3, and the size of the block Db4 is the same as the size of the block B3. The image data decompression unit 12b arranges the block Db3 at the position of the block B3 (2 × 2 lower left portion).

  FIG. 11D shows a state in which the CPU 12 restores and arranges the blocks Db5 and Db6 using the data on the Da5 and Da6 rows of the transfer image data (FIG. 8). First, the image data decompression unit 12b reads Da5 line data from the transfer image data and restores the block Db5. The image data decompression unit 12b tries to arrange the block Db5 at the position of the block B4. However, the resolution number R (2) of the block Db5 is one larger than the restoration resolution number S (1) of the block B4. Therefore, the size of the block Db5 is ¼ the size of the block B4. Therefore, in the same manner as the block A1 is divided into the blocks B1 to B4, the image data expansion unit 12b divides the block B4 into 2 × 2, and the four blocks C1 to C4 having the restoration resolution number S (2) are divided. It is created (see FIG. 6C), and the block Db5 is placed at the position of the block C1 (2 × 2 upper left portion). Hereinafter, the block Db6 is similarly arranged at the position of the block C2 (the upper right portion of 2 × 2).

  In FIG. 11E, the image data decompression unit 12b restores the blocks Db7 to Db9 using the data in the Da7 to Da9 rows of the transfer image data (FIG. 8), and the position of the block C3 (the upper left of 2 × 2) , Upper right, lower left part, positions of blocks D1 to D3) (see FIG. 6D). In FIG. 11F, the image data decompression unit 12b restores the block Db10 using the data of the transfer image data Da10 and arranges it at the position of the block D4 (2 × 2 upper left portion, the position of the block E1). The situation is shown (see FIG. 6E). Note that FIG. 11F is an enlarged view of a portion surrounded by X in FIG.

  FIG. 11G shows a state where the image data decompression unit 12b restores the blocks Db10 to Db14 using the data on the Da11 to Da14 rows of the transfer image data (FIG. 8) and arranges them at the position of the block E2. (See FIG. 7F-1). FIG. 11H shows a state in which the image data decompression unit 12b restores the block Db15 using the data on the Da15 line of the transfer image data and arranges it at the position of the block E3 (FIG. 6E). reference). FIG. 11I shows a state in which the image data decompression unit 12b restores the blocks Db16 to DB19 using the data on the Da16 to Da19 lines of the transfer image data and arranges them at the position of the block E4 (FIG. 11). 7 (E-2)). FIG. 11J shows a state in which the image data decompression unit 12b restores the blocks Db20 to Db23 using the data on the Da20 to Da23 rows of the transfer image data and arranges them at the position of the block E5.

  FIG. 12K shows how the image data decompression unit 12b restores the block Db24 using the data on the Da24 line of the transfer image data (FIG. 8) and arranges it at the position of the block E6. FIG. 12 (L) shows how the image data decompression unit 12b restores the blocks Db25 to Da28 using the data in the Da25 to Da28 rows of the transfer image data and arranges them at the position of the block E7. FIG. 12M shows a state in which the image data decompression unit 12b restores the block Db29 using the data on the Da29th line of the transfer image data and arranges it at the position of the block E8. FIG. 12N shows a state in which the image data decompression unit 12b restores the blocks Db30 to Db32 using the data on the Da30 to Da32 lines of the transfer image data and arranges them at the positions of the blocks D6 to D8. . In FIG. 12 (O), the image data decompression unit 12b restores the blocks Db33 to Db37 using the data on the Da33 to Da37 lines of the transfer image data and arranges them at the positions of the blocks B6, B6, C5, C6, and D9. It shows how to do. FIG. 12 (O) is an enlarged view of a portion surrounded by Y in FIG. 11 (E).

  As described above, according to the first embodiment, the data conversion unit 222 divides an image into as large blocks as possible, and determines whether or not each of the divided blocks is configured with a uniform color. If the divided blocks are not composed of uniform colors, the blocks are divided into finer blocks so as to obtain uniform colors. Then, transfer image data including the resolution number indicating the resolution of each uniform block and the color information of the block is generated and sent to the multifunction device 100. Therefore, it is possible to reduce the data amount of the transfer image data. Further, the image data decompression unit 12b of the multifunction peripheral 100 that receives the transfer image data only restores a block having a size corresponding to the resolution number and arranges it at a predetermined position, so that the data processing of the image data decompression unit 12b is performed. The burden is very small. In addition, the restoration of the image from the transfer image data is reversible, and the quality of the restored image can be maintained at a high quality. Further, in this embodiment, since the division is made with the largest possible block, the data amount of the transfer image data can be reduced. Therefore, according to the present embodiment, it is possible to reduce the amount of data and to suppress the processing load of the entire system while maintaining high quality for the image information.

B. Second Embodiment In the second embodiment, image data for transfer is created directly from drawing data without creating raster image data. FIG. 13 and FIG. 14 are explanatory diagrams for explaining the contents of the division processing when an image component is represented by vector data, using an image. In the first embodiment, the image is converted into raster image data, and the raster image data is represented by bitmap data. Since the contour lines of the image parts in the raster image data are expressed in units of pixels, in the first embodiment, for example, the diagonal lines are stepped as shown in FIGS. On the other hand, in the second embodiment, as shown in FIG. 13 and FIG. 14, even if the block is divided, the diagonal lines (the contour lines of the image parts) do not need to be expressed in units of pixels. It is not in shape.

  The division flowchart is almost the same as the flowchart shown in FIG. The following description will focus on the differences from the first embodiment. In step S510, the data conversion unit 222 acquires the coordinates of the four corners of the image. In the present embodiment, the coordinates of the four corners of the image are (0, 0) at the upper left, (x1, 0) at the upper right, (0, y1) at the lower left, and (x1, y1) at the lower right. Note that the data converter 222 creates image transfer data from the drawing data, so it is not necessary to create raster image data.

  In the block division of step S520, the data conversion unit 222 acquires the coordinates of the four corners of the blocks A1 to A16 obtained by the block division. As shown in FIG. 13A, the coordinates of the points shared by the blocks A1, A2, A5, A6 are (x2, y3), and the coordinates of the points shared by the blocks A2, A3, A6, A7 are (x3, y3). ), For example, the coordinates of the four corners of the block A1 are (0, 0), (x2,), (0, y3), (x2, y3), and the coordinates of the four corners of the block A2 are (x2, 0), (X3, 0), (x2, y3) (x3, y3). Note that the values of x2, x3, and y3 can be easily obtained using x1, y1 and the number of block divisions. For example, x2 = x1 / 4, x3 = x1 / 2, and y3 = y1 / 4. Note that the coordinates of the four corners can be similarly obtained for the blocks A3 to A16. These coordinates can be easily expressed using x1 and y1. In the second embodiment, block division means obtaining coordinates of four corners of each block after division. These coordinates are used when determining whether a block is uniform.

  In step S545, the data converter 222 divides the block A2 into blocks B1 to B4. At this time, the data conversion unit 222 can easily obtain the coordinates of the four corners of the blocks B1 to B4. In FIG. 13B, the coordinates of the blocks B1 to B4 when the coordinates of the points shared by the four corners of the blocks B1 to B4 are (x4, y4) are shown using x2, x3, x4, y3, and y4. ing. x4 and y4 can be obtained by x4 = (x2 + x3) / 2 and y4 = y3 / 2, respectively. As described above, since x2, y2, and y4 can be expressed using x1 and y1, x4 and y4 can also be expressed using x1 and y1, and x4 = 3x1 / 8, y4 = y1. / 8. As a result, the coordinates of the blocks B1 to B4 can be similarly expressed using x1 and y1. Similarly, the data conversion unit 222 acquires the coordinates of the four corners of each block generated by block division up to FIG.

  As shown in FIG. 14 (F-1), the data conversion unit 222 divides the block E2 into blocks F1 to F4 at the division resolution R (5) (2400 dpi). In the first embodiment, the sizes of the blocks F1 to F4 are the same as the size of one pixel of the raster image data, and the blocks F1 to F4 are uniform. On the other hand, in the second embodiment, the blocks F1 and F3 are uniform, but the blocks F2 and F4 are not uniform because a line of y = f (x) indicating a contour line passes therethrough. The data converter 222 executes steps S530 and S550 for the block F1, and stores the resolution number and RGB data in the Da1 line of the transfer image data.

  Regarding the block F2, the colored side of the outline of y = f (x) is defined as a colored region F2A, and the non-colored side is defined as a non-colored region F2B. In the case of vector data, since the contour line is given by a function, if the contour line passes through the block, the block has two colors regardless of the division resolution of the block. In step S535, the data conversion unit 222 determines whether or not the current set division resolution R (i) is the highest division resolution Rmax. The set division resolution R (5) when the data conversion unit 222 generates the blocks F1 to F4 is equal to the highest division resolution Rmax (2400 dpi). Therefore, the data conversion unit 222 moves the process to step S550.

  In step S550, the data conversion unit 222 acquires RGB data of the block F2. The data converter 222 calculates the average color of the block F2 using the size and color of the colored region F2A and the size and color of the non-colored region F2B. Then, the RGB data of the average color is stored in the transfer image data. The data converter 222 performs the same processing on the blocks F3 and F4, and stores the RGB data in the transfer image data.

  FIG. 14F-3 illustrates a state in which the block E4 (see FIG. 13E) is divided at the set division resolution R (5) (2400 dpi). FIG. 14 (F-4) shows a state in which the blocks F5 to F8 are colored with the average color as in the blocks F1 to F4 described above. Thus, if each of the blocks F5 to F8 is colored with an average color, each of the blocks F5 to F8 becomes uniform.

  FIG. 15 is an explanatory diagram illustrating an example of a method for determining whether or not a block is uniform when an image component is represented by vector data. These determination processes are executed by the determination unit 224. In the case of vector data, the contour line of the image component to be drawn can be represented by y = f (x). Here, x and y are position coordinates in the screen. First, in FIG. 15A, the determination unit 224 determines whether or not the contour line crosses four sides of the block. If the outline crosses any of the four sides of the block, the block has at least two colors. Therefore, in such a case, the data conversion unit 222 increases the set division resolution R (i).

First, the determination unit 224 acquires the coordinates of the four corners of the block. Since the coordinates are acquired when the data conversion unit 222 performs block division as described above, the determination unit 224 may acquire the value. The coordinates of the four corners are (xa, ya) (xb, ya) (xa, yb) (xb, yb). Next, the determination unit 224 determines that f (xa) is between ya and yb, f (xb) is between ya and yb, f ⁻¹ (ya) is between xa and xb, f ^-1 (yb) is between xa and xb, it is determined that the figure crosses the four sides of the block. Here, x = f ⁻¹ (y) is an inverse function of y = f (x).

  In FIG. 15B, the determination unit 224 determines whether or not the figure exists inside the block. This determination is executed when none of the four conditions shown in FIG. The determination unit 224 determines whether y is between ya and yb and x is between xa and xb. If both are satisfied, the outline will be included in the block, so the block has at least two colors. Therefore, in such a case, the data conversion unit 222 increases the set division resolution R (i). Since restoration is the same as that in the first embodiment, the description thereof is omitted.

  As described above, a configuration in which image data for transfer is created directly from drawing data without creating raster image data, as in the second embodiment, may be employed. In this case, it is not necessary to create raster image data.

C. Third embodiment:
FIG. 16 is an explanatory diagram showing the third embodiment. The apparatus configuration of the third embodiment is the same as that of the first embodiment. In the first embodiment, the division resolution determination unit 223 of the personal computer 200 acquires resolution information for determining the division resolution for dividing the image from the multi-function peripheral 100. In the second embodiment, The difference is that the application execution unit 21 acquires the image from the image being processed.

  FIG. 16A is an explanatory diagram showing an image 700. The image 700 is an image of horizontal X pixels and vertical Y pixels. FIG. 16B is an enlarged view of a portion (upper left portion) surrounded by Z in FIG. In this embodiment, the size of one pixel of the image is 300 dpi × 300 dpi ((1/300 inch) × (1/300 inch)). The division resolution determination unit 223 (FIG. 2) uses the 300 dpi as the highest division resolution, and obtains a plurality of division resolutions for dividing the image, as in the first embodiment. The values are, for example, 300 dpi, 150 dpi, and 75 dpi. Note that the minimum division resolution can be arbitrarily determined, and in this embodiment, a value when it becomes 100 dpi or less is used. On the other hand, the division resolution determination unit 223 can also obtain a plurality of division resolutions from the maximum print resolution 2400 dpi of the multifunction peripheral 100. The values are, for example, 2400 dpi, 1200 dpi, 600 dpi, 300 dpi, 150 dpi, and 75 dpi. Here, when both are compared, they agree at a division resolution of 300 dpi or less. When the two divided resolutions match, the divided resolution determination unit 223 adopts the divided resolution. In this case, the data conversion unit 222 does not need to divide the image with a division resolution of 600 dpi or more, which is twice the resolution of one pixel of the image, and can reduce the burden of data processing.

  FIG. 16C shows a case where the resolution of one pixel of the image is 400 dpi × 400 dpi. The division resolution determination unit 223 (FIG. 2) obtains a plurality of division resolutions using the 400 dpi as the highest division resolution. The values are, for example, 200 dpi, 100 dpi, and 50 dpi. In this embodiment, the value when the minimum division resolution is 100 dpi or less is used. On the other hand, the division resolution determination unit 223 can also obtain a plurality of division resolutions from the maximum print resolution 2400 dpi of the multifunction peripheral 100. The values are, for example, 2400 dpi, 1200 dpi, 600 dpi, 300 dpi, 150 dpi, and 75 dpi. When they are compared here, they do not agree. In such a case, the division resolution determination unit 223 determines whether there is a resolution that is an integer multiple of the 300 dpi resolution obtained from the size of one pixel of the image among the plurality of division resolutions obtained from the maximum print resolution of the multifunction peripheral 100. Find out. In this embodiment, 1200 dpi and 2400 dpi correspond. The divided resolution determination unit 223 employs a plurality of divided resolutions, 1200 dpi, 600 dpi, 300 dpi, 150 dpi, and 75 dpi, with 1200 dpi being the lowest resolution as the highest divided resolution. In the case of the present embodiment, when 1200 dpi is used as the maximum division resolution, the size of one pixel of the image 700 is an integral multiple of the size of the smallest block among the blocks used for division. In such a case, when the data conversion unit 222 divides the image into blocks with the highest division resolution of 1200 dpi, the 1200 dpi block does not span a plurality of pixels. On the other hand, when the highest resolution is 600 dpi, for example, as shown in FIG. 16C, the block W1 does not straddle two pixels, but the block W2 straddles two pixels. Further, in this embodiment, division at a division resolution of 2400 dpi is unnecessary, and the burden of data processing can be reduced. Since the processes other than determining a plurality of division resolutions are the same as those in the first embodiment, description of these processes will be omitted.

  As described above, according to the third embodiment, it is possible to acquire each resolution for dividing an image using the image processed by the personal computer 200.

D. Fourth embodiment:
FIG. 17 is an explanatory diagram showing the fourth embodiment. The apparatus configuration of the fourth embodiment is the same as that of the first embodiment. In the fourth embodiment, when the image size is horizontal X pixels and vertical Y pixels, the divided resolution determination unit 223 uses the greatest common divisor (GCD: Greatest Common) of the horizontal and vertical pixel numbers X and Y. The difference is that the resolution of division is determined based on (Divisionor). That is, M = GCD (X, Y) when the maximum block size when dividing an image into blocks is M pixels. Then, the data conversion unit 222 determines whether or not each block is uniform for each M pixel × M pixel block, and if the block is not uniform, the block is converted into four small blocks of 2 × 2. To divide. Note that the size of the divided blocks is (M / 2 pixels) × (M / 2 pixels). After that, similarly to the case of the first embodiment, the image data for transfer is generated by performing fine block division in order. When the size of the divided block is N pixels × N pixels (N is an odd number), the data converter 222 divides into N × N N ² blocks in the next division, Subsequent block division may be stopped. In this way, a block having a size of 1 pixel × 1 pixel can be used as the minimum block. In this embodiment, a block of M pixels × M pixels corresponds to a block with the minimum division resolution in the first embodiment, and a block of 1 × 1 pixels corresponds to a block of the maximum division resolution in the first embodiment.

  In the case of the fourth embodiment, the largest block has an integer number in the vertical direction and an integer number in the horizontal direction. That is, in the fourth embodiment, the maximum block can be divided up to the end portion, and no half end is generated. Therefore, in particular, in the case of an image having a single background and including figures and characters, the blocks are not too fine at the end portions, and small blocks are unlikely to occur. As a result, the data amount can be reduced. Further, in the fourth embodiment, the printing resolution of the multifunction peripheral need not be used as a reference.

  FIG. 18 is an explanatory view showing a modification of the fourth embodiment. The modification of the fourth embodiment is applied when the value of the greatest common divisor becomes smaller than a predetermined value in the fourth embodiment. That is, if the value of the greatest common divisor is small, the size of the block to be divided first becomes small, and the amount of data increases. In this modification, the size of the first block to be divided is increased in such a case.

The divided resolution determination unit 223 (FIG. 2) first sets the maximum block size to M × M pixels. Here, M is a value satisfying M = 2 ⁿ (n is an integer of 2 or more, preferably n = 4 to 6). The ^reason for 2 ⁿ is that when the block is divided finely, the size of each block up to the smallest block size of 1 × 1 pixel is m × m pixels (m is an integer). Because. Note that the value of M may be determined in advance.

The data conversion unit 222 (FIG. 2) creates a virtual space 800 that is larger than the size of the image 700. The virtual space 800 is a rectangular area obtained by arranging the largest blocks in a tile shape, and is the smallest area including the image 700. If the size of the image 700 is (X pixels) × (Y pixels) and the maximum block size is 2 ⁿ , the size of the virtual space 800 is (P−1) × 2 ⁿ <X ≦ P × 2 ⁿ and (Q-1) × 2 ⁿ <X ≦ Q × 2 ⁿ (P and Q are integers). Next, the data conversion unit 222 arranges the image 700 in the upper left part of the virtual space 800.

  The data converter 222 regards the virtual space 800 as a new image, divides the image as in the first embodiment, and creates transfer image data. Note that the data conversion unit 222 regards an area (right part and lower part) where the image 700 is not placed in the virtual space 800 as having the same color as the right edge and the lower edge of the image 700. Then, image transfer data may be created. Since this transfer image data processing is the same as that in the first embodiment, a description thereof will be omitted. Even if the data conversion unit 222 performs the processing in this way, the processing load does not increase so much. Even at the time of restoration, if the size of the original image 700 is included in the image transfer data for the portion that protrudes from the image 700, the image data decompression unit 12b causes the portion of the data that protrudes from which line. Can be easily determined. Therefore, the image data decompression unit 12b can reduce the load of the restoration process by ignoring the data of the portion of the transfer image data that protrudes from the image 700.

  As described above, according to the modification of the fourth embodiment, the virtual space 800 is used even when the greatest common divisor of X and Y, which are the number of pixels in the horizontal and vertical directions of the image 700, is a small value. The virtual space 800 is divided into images using as large blocks as possible. As a result, the number of small blocks can be reduced. In this embodiment, the image 700 is arranged at the upper left corner of the virtual space 800, but may be arranged at another corner (upper right, lower left, lower right) or the center of the virtual space 800.

E. Fifth embodiment:
FIG. 19 is an explanatory diagram showing the fifth embodiment. The fifth embodiment is an explanatory diagram illustrating an embodiment when the vertical print resolution and the horizontal print resolution of the multifunction peripheral 100 are different. In the example shown in FIG. 19A, the printing resolution of the multifunction peripheral 100 is 2400 dpi × 1200 dpi. In this case, the smallest block is a rectangle having an aspect ratio of 2. The next smallest block becomes a square block by combining two of the minimum blocks. In the example shown in FIG. 19B, the resolution of the multifunction peripheral 100 is 4800 dpi × 1200 dpi. In this case, the smallest block is a rectangle having an aspect ratio of 4. The next smallest block is a square block formed by combining the four smallest blocks. In the example illustrated in FIG. 19C, the resolution of the multifunction peripheral 100 is 1200 dpi × 1800 dpi. In this case, the smallest block is a rectangle having an aspect ratio of 2/3. The next smallest block is a square block formed by combining six of the minimum blocks. In the example shown in FIG. 19D, the aspect ratio of each block used for division is the same as the aspect ratio of the resolution (2400 dpi × 1200 dpi) of the multi-function device 100 regardless of the block size. In this case, the shape of the block does not become a square.

  As shown in the fifth embodiment, the vertical resolution and the horizontal resolution of the multifunction peripheral 100 may be different. Further, the shape of the block is not limited to a square, and it is possible to adopt rectangles with various aspect ratios.

F. Sixth embodiment:
FIG. 20 is an explanatory diagram showing the sixth embodiment. In the first embodiment, for the division other than the first division, block division is performed in which the block is divided into four blocks of 2 × 2, but the number of divisions is not limited to this, and the number of divisions is 3 × 3 or 4 × 4. The block division may be used. If the division from the division resolution R (1) to the resolution R (2) is 3 × 3 division, the division from the division resolution R (2) to the division resolution R (3) is also 3 × 3 division. In addition, it is preferable from the uniformity of the division process that the divisions when the division resolution is increased by one are all the same, but the number of divisions at each stage may be different. That is, as shown in FIG. 18, the division from the division resolution R (1) to the division resolution R (2) is 3 × 3 division, and the division from the division resolution R (2) to the division resolution R (3) is 2 ×. The division into two divisions and the division resolution R (3) to the division resolution R (4) may be different at each stage such as 4 × 4 division. Thereby, it is possible to obtain the flexibility of the division process. In addition, it is preferable to divide the block into 2 × 2 rather than 3 × 3 or 4 × 4 because the size of the next block can be increased. In addition, when the fifth and sixth embodiments are combined, the block division can be divided into various divisions represented by n × m (n and m are integers of 2 or more) such as 2 × 3 and 3 × 4. . Further, the vertical / horizontal resolution ratio may be changed.

  In the above embodiment, the print data is sent from the personal computer 200 to the multifunction peripheral 100 as an example. However, the present invention can also be applied to the case where the display data is sent to a display device such as a display. In this case, the display resolution of the display may be the highest division resolution.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

10 ... Control circuit 11 ... Memory 12 ... CPU
12a ... Data reception control unit 12b ... Image data decompression unit 12c ... Color conversion unit 12d ... Halftone processing unit 12e ... Unit 13 ... Printer engine 14 ... Reading unit 15 ... Operation unit 16 ... Display unit 17 ... Network interface unit 20 ... CPU
DESCRIPTION OF SYMBOLS 21 ... Application execution part 22 ... Printer driver 31 ... Memory 32 ... Hard disk 34 ... Network interface part 100 ... Multifunction machine 150 ... Cable 200 ... Personal computer 201 ... Computer main body 202 ... Display apparatus 203 ... Keyboard 204 ... Mouse 221 ... Raster data expansion | deployment Unit 222 ... data conversion unit 223 ... division resolution determination unit 224 ... determination unit 225 ... data transmission control unit 400 ... image transfer system 500 ... raster image data 501 ... block 511 ... block 521 ... block 551 ... block 600 ... frame 700 ... image 800 ... virtual space Rmin ... lowest division resolution Rmax ... highest division resolution Da1 to Da37 ... row Db1 to Db37 ... block

Claims (6)

An image processing apparatus,
A resolution determination unit for determining a plurality of division resolutions to be used when dividing an image;
A data generation unit that generates multi-resolution image data representing the image using a plurality of types of blocks corresponding to the plurality of divided resolutions;
With
The resolution determination unit
Determining a minimum division resolution among the plurality of division resolutions based on a greatest common divisor of the number of vertical pixels and the number of horizontal pixels of the image;
Determining the plurality of division resolutions to have a value obtained by multiplying the minimum division resolution by an integer;
The data generator is
Dividing the image into a plurality of uniform blocks using the largest possible block of the plurality of types of blocks,
Generating multi-resolution image data including a resolution number indicating the resolution of each uniform block obtained by the block division and color information of the block;
Image processing device. The image processing apparatus according to claim 1.
In the process of generating the multi-resolution data, the image data generation unit,
(A) setting the lowest division resolution among the plurality of division resolutions as a set division resolution, and setting the entire image as a division target image area;
(B) dividing the division target image area into a plurality of blocks at the set resolution;
(C) sequentially selecting one block among the plurality of divided blocks as a processing target block;
(D) determining whether the processing target block is uniform;
(D-1) When the processing target block is uniform, the resolution information indicating the set division resolution and the color information indicating the color of the processing target block are converted into multi-resolution image data representing the processing target block. And return to the process (c) to continue the process after the process (c),
(D-2) When the processing target block is not uniform,
(D-2-1) If the next highest division resolution of the set division resolution is equal to or lower than the highest division resolution among the plurality of division resolutions, the next highest division resolution is set as a new setting division resolution. Set and set the processing target block as a new division target image area, return to the processing (b), and execute the processing after the processing (b),
(D-2-2) When the next highest division resolution of the set division resolution exceeds the highest division resolution among the plurality of division resolutions, resolution information indicating the set division resolution and the processing target block And color information indicating the color of the multi-resolution image data representing the processing target block,
(E) In the process (c), when there is no next block among a plurality of blocks having the set division resolution and when the process (d-2-2) is performed, the setting is performed. Set the division resolution to the next lower division resolution, and return to the process (c) to execute the process after the process (c).
Image processing device. The image processing apparatus according to claim 2,
The image processing apparatus, wherein a ratio between the set divided resolution and the next highest divided resolution in the process (d-2-1) is a constant ratio regardless of the size of the set divided resolution. The image processing apparatus according to claim 4.
The ratio between the set division resolution in the process (d-2-1) and the division resolution with the next lowest division resolution is 2.
When returning to the processing (b), the image data generating unit divides the block into 2 × 2 4 blocks. An image processing method comprising:
Determining a plurality of division resolutions to be used when dividing an image;
Generating multi-resolution image data representing the image using a plurality of types of blocks corresponding to the plurality of divided resolutions;
With
The minimum division resolution among the plurality of division resolutions is determined based on the greatest common divisor of the number of vertical pixels and the number of horizontal pixels of the image,
The plurality of division resolutions have a value obtained by multiplying the minimum division resolution by an integer,
The process of generating image data includes
Dividing the image into a plurality of uniform blocks using the largest possible block of the plurality of types of blocks;
Generating multi-resolution image data including a resolution number indicating the resolution of each uniform block obtained by the block division and the color information of the block;
An image processing method. A computer program comprising:
Means for determining a plurality of division resolutions to be used when dividing an image;
Means for generating multi-resolution image data representing the image using a plurality of types of blocks corresponding to the plurality of divided resolutions;
Function as
The minimum division resolution among the plurality of division resolutions is determined based on the greatest common divisor of the number of vertical pixels and the number of horizontal pixels of the image,
The plurality of division resolutions have a value obtained by multiplying the minimum division resolution by an integer,
The image data generation means
A dividing unit that divides the image into a plurality of uniform blocks using the largest possible block among the plurality of types of blocks;
Data generation means for generating multi-resolution image data including a resolution number indicating the resolution of each uniform block obtained by the block division and color information of the block;
Having
Computer program.

Images