JP5262882B2 - Image processing apparatus and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for processing an image increasing the speed of a drawing process and keeping high quality. <P>SOLUTION: By executing either or both of drawing by an Index value and drawing using a color value of drawing information for exclusively keeping necessary pixels or regions in accordance with the Index value (Index number or attribute information), the speed of a drawing process is increased, and high quality is kept. In particular, when collision of Index numbers used as keys of an Index table occurs or drawing of a photograph image is executed, the drawing by the Index value and the drawing using the color value of the drawing information are executed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  Conventionally, a printer renders PDL data received from a network using CMYK data after gradation processing for each band. In some cases, image data (CMYK data) is encoded by a compression algorithm such as JBIG and the encoded data is stored in a memory in order to be printed out later. In recent years, there has been a demand for higher image quality, and some printers perform ROP processing (logical operation processing) and translucent processing using RGB data in order to cope with higher image quality.

  In Patent Document 1, in the color conversion process of RGB-> CMYK, for each color conversion, the color before conversion and the color after conversion are registered on the work memory with a hash function value, and the color before conversion is converted before color conversion. A technique for speeding up the color conversion processing by searching whether the hash function value is registered in the work memory and using the color value after the registration is disclosed is disclosed.

  In Patent Document 2, the number of colors to be drawn for each band is counted before the drawing process. If the number of colors of the entire band is 2 or less, the band is drawn with a 1-bit color palette, and the number of colors of the entire band is If the number of colors is 4 or less, the drawing time is reduced by changing the number of BITs in the color palette according to the number of colors used in the band, such as drawing a band with a 2-bit color palette. The amount is reduced.

  Further, in Patent Document 3, in order to realize appropriate data processing according to image attributes, an image memory for storing a multi-value color rendering result and an attribute memory corresponding to the pixel unit are provided. The attribute memory uses a plurality of BITs and has only a mode for storing attribute values (characters / photos / graphics, etc.) and an image memory for storing multi-valued color rendering results. A mode is disclosed in which the memory capacity is reduced by using the lower 3 bits of 8 bits for attribute values (character / photo / graphic, etc.).

  However, when the color palette format is changed in band units as in the technique disclosed in Patent Document 2, it is possible to increase the speed of text-only sentences, but graphics images and photographic images may be a little. If it is included, the band becomes a large format, and it is necessary to draw the white background portion in a large format, resulting in a poor compression rate and a low speed. In addition, the color to be drawn and the color palette color (256 colors) are sequentially compared when the color palette is generated. In this way, if 256 color palettes are compared each time drawing is performed, the processing speed is increased. Becomes slower.

  This is achieved by using a hash function as in the technique of Patent Document 1 and comparing it with the color palette of the obtained key value address. Since it cannot be made to correspond one-on-one, a key collision occurs. In the color conversion device of Patent Document 1, when a key collision occurs, the color is recalculated. However, when drawing processing is considered, in the format of only the color palette as in Patent Document 2, that part is calculated. It is not possible to draw only with RGB values. Further, in Patent Document 2, when even one ROP calculation process is included in the band, it is necessary to draw all the bands with RGB 24 bits, and the processing speed is reduced.

  In addition, as in the technique of Patent Document 3, it is necessary to prepare an attribute memory separately in order to realize appropriate data processing according to the attribute of the image, which leads to an increase in cost, and in order to reduce the memory capacity, If only the memory is used and the lower 3 bits of the 8-bit RGB value Blue are used for the attribute value (character / photo / graphic, etc.), the image quality is lowered and the image quality cannot be maintained.

  The present invention has been made in view of the above, and provides an image processing apparatus and an image processing method capable of speeding up a drawing process and maintaining high image quality.

In order to solve the above-described problems and achieve the object, an image processing apparatus of the present invention analyzes input information and generates drawing information generation means (302) for generating drawing information including color information, and the generated information Index number generation means (305) for generating an Index number from the color information of the drawing information using a hash function, and Index unused determination means for determining whether the Index number generated by the Index number generation means is unused. (305) and an index table storage unit (306) for storing the set of the index number and the color information as an index table when the index unused determination unit determines that the index number is unused. , When it is determined by the Index unused determination means that the Index number has been used, Index color determination means (307) for acquiring color information corresponding to the Index number stored in the Index table storage means and determining whether the color information is the same as the color information of the drawing information; and the Index color When it is determined by the determination means that the two color information are the same, the Index number drawing means (309) for drawing the Index number, and the Index number drawn by the Index number drawing means is set as the Index on the Index page. An index data storage means (311) for storing values and an index color determination means, when it is determined that the two color information are different, indicates an attribute of an image to be drawn that is a value that is not used as an index number. Attribute information rendering means (309) for rendering a value on the Index page, and the Inde An image comprising a drawing means (308) for drawing a color value indicated by the color information of the drawing information and a page drawn by the drawing means when the color determining means determines that the two color information are different. Image data storage means (310) for storing data, the Index value stored in the Index data storage means and the color information stored in the image data storage means are read for each pixel, and based on the read Index value For the index value indicating the index number, the converted color information obtained by converting the index number into color information by accessing the index table is used, and the index value indicating the attribute of the image to be rendered is used. Index value conversion for outputting image data composed of the color information using the color information stored in the image data storage means Means (312, 313) and image processing means (314) for performing image processing on the image data from the index value conversion means.

Also, the image processing apparatus of the present invention analyzes input information and generates drawing information generation means for generating drawing information including color information, and generates an index number using a hash function from the color information of the generated drawing information. Index number generating means for performing the index number generation, determining whether the index number generated by the index number generating means is unused, and determining whether the index number is unused by the index unused determining means. In this case, the Index table storage means for storing a set of the Index number and the color information including the attribute information of the image to be drawn as an Index table, and the Index unused determination means, the Index number is determined by the Index table storage means. When it is determined that it has been used, the I stored in the Index table storage means Color information corresponding to the dex number is acquired, Index color determination means for determining whether the color indicated by the color information is the same as the color indicated by the color information of the drawing information, and an object to be drawn is determined based on the drawing information. A drawing attribute determining unit (304) for determining whether or not to draw with a small number of colors and determining an attribute of a pixel to be drawn, and an object to be drawn is drawn with a small number of colors by the drawing attribute determining unit. When it is determined that there is an index number, and the Index color determination unit determines that the colors indicated by the two color information are the same, the Index number drawing unit for drawing an Index number and the Index number drawing unit and Index data storing means for storing the Index number to be drawn as Index value Index page, by the Index color determining means, When it is determined that the two pieces of color information are different from each other, the attribute information rendering unit that renders a value that is not used as the Index number and that indicates the attribute of the image to be rendered on the Index page, and the Index color determination unit When it is determined that the two color information are different from each other, an image data storage for storing image data composed of a drawing means for drawing a color value indicated by the color information of the drawing information and a page drawn by the drawing means And the index value stored in the index data storage unit and the color information stored in the image data storage unit are read for each pixel, and based on the read index value, an index value indicating an index number is obtained. On the other hand, the converted color information obtained by converting the Index number into color information by accessing the Index table is used. The index value of the value indicating the attribute of the image to be drawn is determined by the color information stored in the image data storage means, the image data using these color information, and the drawing attribute determination means. Index value conversion means (1612) for outputting the attribute information, and image processing means for performing image processing on the image data based on the attribute information using the image data and attribute information from the Index value conversion means. It is characterized by having.

The present invention is also an image processing method in an image processing apparatus, comprising: a drawing information generating step of analyzing input information and generating drawing information including color information; and a hash function from the color information of the generated drawing information The Index number generation step for generating an Index number using the Index number, the Index number generation step for determining whether the Index number generated by the Index number generation step is unused, and the Index unused determination step, An index table storage step of storing the set of the index number and the color information in an index table storage means for storing the set of the index number and the color information as an index table when it is determined that the index number is unused And the Index number unused determination step, the Index number is already used. When it is determined that there is an index color determination step of acquiring color information corresponding to the Index number stored in the Index table storage means and determining whether the color information is the same as the color information of the drawing information When the Index color determination step determines that the two color information is the same, the Index number drawing step for drawing the Index number, and the Index number drawn by the Index number drawing step are displayed on the Index page. In the Index data storage means for storing the Index value of the Index page, when the Index data storage step for storing the Index value of the Index page and the Index color determination step determine that the two color information are different, the Index number A value indicating an attribute of an image to be drawn that is a value that is not used as a drawing step of drawing a color value indicated by the color information of the drawing information when the attribute information drawing step of drawing on the dex page and the index color determination step determine that the two color information are different; In the image data storage means for storing image data composed of pages rendered by the rendering process, the image data storage process for storing the image data, the Index value stored in the Index data storage means, and the image data storage means After the conversion in which the stored color information is read for each pixel and the Index number is converted into the color information by accessing the Index table for the Index value indicating the Index number based on the read Index value. The image data storage means for the index value of the value indicating the attribute of the image to be drawn An index value converting step of outputting image data composed of the color information using the color information stored in the image information, and an image processing step of performing image processing on the image data from the index value converting step. To do.

The present invention is also an image processing method in an image processing apparatus, comprising: a drawing information generating step of analyzing input information and generating drawing information including color information; and a hash function from the color information of the generated drawing information The Index number generation step for generating an Index number using the Index number, the Index number generation step for determining whether the Index number generated by the Index number generation step is unused, and the Index unused determination step, When it is determined that the Index number is not used, the Index table storage means for storing a set of the Index number and the color information including the attribute information of the image to be drawn as an Index table is stored in the Index table storage means. Index table storage step for storing a set of color information including attribute information of an image to be stored When the Index unused determination step determines that the Index number has been used, the color information corresponding to the Index number stored in the Index table storage unit is acquired, and the color indicated by the color information Is determined to be the same as the color indicated by the color information of the drawing information, and from the drawing information, it is determined whether the object to be drawn is drawn with a small number of colors, and the pixel to be drawn is determined. The drawing attribute determining step for determining the attribute and the drawing attribute determining step determine that the object to be drawn is to be drawn with a small number of colors, and the Index color determining step determines the two color information When it is determined that the colors to be displayed are the same, the Index number drawing step for drawing the Index number and the Index number drawing step for drawing And Index data storage step of storing the Index number to be as Index value Index page, by the Index color judgment step, when the two color information is determined to be different, rendering a value not used as Index Number The color information indicated by the color information of the drawing information when the attribute information drawing step of drawing a value indicating the attribute of the image to be displayed on the Index page and the Index color determination step determine that the two color information are different. A drawing process for drawing a value; an image data storage means for storing image data composed of pages drawn in the drawing process; an image data storage process for storing the image data; and an index data storage means stored in the index data storage means Read index value and color information stored in the image data storage means for each pixel Based on the index value, for the index value indicating the index number, the converted color information obtained by converting the index number into color information by accessing the index table is used to change the attribute of the image to be rendered. For the Index value indicated, the color information stored in the image data storage means is used to output the image data using these color information and the attribute information determined in the drawing attribute determination step. An index value converting step; and an image processing step of performing image processing on the image data based on the attribute information using the image data and the attribute information from the index value converting step.

  According to the present invention, drawing using an Index value and drawing using color information of drawing information for only a necessary pixel or region are performed in accordance with an Index value (an index number or a value representing an attribute). As a result, the effects of speeding up the drawing process and maintaining high image quality can be obtained.

FIG. 1 is a diagram illustrating a configuration example of a mechanism unit of a multicolor image forming apparatus embodying the present invention. FIG. 2 is a block diagram showing the configuration of the electrical / control apparatus in the image forming apparatus of FIG. FIG. 3 is a block diagram showing a flow of image processing according to the embodiment of the present invention. FIG. 4 is a diagram illustrating an example of the Index table in the present embodiment. FIG. 5 is a diagram showing the configuration of the memory space of the main memory in the present embodiment. FIG. 6 is a diagram showing a data storage format (Index format) in the main memory of the Index page in the present embodiment. FIG. 7 is a diagram showing a data storage format (CMYK format) in the main memory of the CMYK page in this embodiment. FIG. 8 is a flowchart for explaining processing in the present embodiment. FIG. 9 is a flowchart of the pre-drawing process of FIG. FIG. 10 is a flowchart of the drawing process of FIG. FIG. 11 is a flowchart of the Index drawing process of FIG. FIG. 12 is a flowchart of the Index & CMYK drawing process of FIG. FIG. 13 is a diagram illustrating a drawing example (final output) in the present embodiment. FIG. 14 is a diagram illustrating a drawing example of Index values and CMYK values in the main memory according to the present embodiment. FIG. 15 is a block diagram showing a second configuration of the electrical / control apparatus in the image forming apparatus of FIG. FIG. 16 is a diagram illustrating a hardware configuration of the image processing unit in FIG. 15. FIG. 17 is a diagram showing a processing flow in the Index value conversion unit of FIG. FIG. 18 is a diagram illustrating an example of an Index format in which attribute information is assigned in bit units.

  Exemplary embodiments of an image processing apparatus and an image processing method according to the present invention are explained in detail below with reference to the accompanying drawings.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of a mechanism unit of a multicolor image forming apparatus embodying the present invention. In this multicolor image forming apparatus (hereinafter abbreviated as an image forming apparatus), reference numeral 1 denotes a belt-like photoconductor as an image carrier, and the photoconductor 1 is rotatably supported by rotating rollers 2 and 3. The rotary rollers 2 and 3 are driven to rotate in the direction of arrow A. On the outer periphery of the photoreceptor 1, a charging device 4 as a charging unit, a static elimination lamp L, and a cleaning blade 15 </ b> A for the photoreceptor 1 are arranged. At the downstream position of the charging device 4, there is an optical writing unit that is irradiated with laser light emitted from a laser writing unit 5 that is optical writing means.

  A multi-color developing device 6 in which a plurality of developing units (developing means) are supported in a switchable manner is disposed downstream of the optical writing unit. The multicolor developing device 6 includes a yellow developing unit, a magenta developing unit, and a cyan developing unit for each color of toner to be accommodated. A black developing unit 7 containing black toner is provided at the top of the multicolor developing device 6.

  Any one of these development units moves to a developable position in synchronization with the development timing of the corresponding color. The multicolor developing device 6 has a function of selecting any developing unit by rotating 120 degrees on the circumference. When these developing units operate, the black developing unit 7 moves to a position separated from the photoreceptor 1. The movement is performed by the rotation of the cam 45.

  The laser writing unit 5 sequentially generates laser light according to image forming signals (writing information) of a plurality of colors from a laser light source (not shown), and periodically uses the polygon mirror 5B rotated by the polygon motor 5A. Then, the surface of the charged photoreceptor 1 is scanned through the fθ lens 5C and the mirror 5D, and an electrostatic latent image is formed on the surface.

  The electrostatic latent image formed on the surface of the photoreceptor 1 is developed with toner from the corresponding developing unit, and a toner image is formed and held. The intermediate transfer belt 10 is adjacent to the photoreceptor 1 and is supported by rotating rollers 11 and 12 so as to be rotatable in the arrow B direction. The toner image on the photoreceptor 1 is transferred onto the surface of the intermediate transfer belt 10 by a transfer brush (first transfer means) 13 on the back side of the intermediate transfer belt 10.

  The surface of the photoreceptor 1 is cleaned for each color by the cleaning blade 15A, and a toner image of a predetermined color is formed on the surface. Each time the intermediate transfer belt 10 is rotated, the toner image on the photosensitive member 1 is transferred to the same position on the surface, and a plurality of color toner images are superimposed and held on the intermediate transfer belt 10. The Thereafter, the toner image is transferred to a recording medium such as paper or plastic.

  At the time of transfer onto the paper, the paper stored in the paper feeding device (paper feeding cassette) 17 is fed out by the paper feeding roller 18 and transported by the transporting roller 19, and is temporarily applied to the registration roller pair 20. After being stopped, the toner image is transferred to the nip between the intermediate transfer belt 10 and the transfer roller (second transfer means) 14 at a timing so that the transfer position of the toner image becomes normal. Then, after the toner images of a plurality of colors on the intermediate transfer belt 10 are collectively transferred by the action of the transfer roller 14, the sheet is sent to the fixing device 50, where the toner image is fixed, and then the paper discharge roller pair 51. As a result, the paper is discharged to the paper discharge stack 52 at the top of the main body frame 9.

  The intermediate transfer belt 10 is provided with a cleaning device 16 for the intermediate transfer belt 10 at a portion of the rotation roller 11 so that the cleaning blade 16A can be contacted and separated via a cleaning blade contacting / separating arm 16C. In the process of receiving the toner image from the photoreceptor 1, the cleaning blade 16A is separated from the intermediate transfer belt 10 and comes into contact after the toner image is transferred from the intermediate transfer belt 10 to the paper. The residual toner after the toner is transferred is scraped off. As already described, the cleaning blade 16A is for the photoreceptor 1 and the intermediate transfer belt 10. Waste toner scraped by these blades is stored in a collection container 15. The collection container 15 is replaced as appropriate. An auger 16B provided inside the cleaning device 16 for the intermediate transfer belt 10 conveys waste toner scraped off by the cleaning blade 16A and sends it to the collection container 15 by a conveying means (not shown).

  Reference numeral 31 denotes a unitized process cartridge that incorporates the photosensitive member 1, the charging device 4, the intermediate transfer belt 10, the cleaning device 16, a conveyance guide 30 that forms a paper conveyance path, and the like so that they can be replaced when the end of their service life is reached. It is configured. In addition to the replacement of the process cartridge 31, the multi-color developing device 6 and the black developing unit 7 are also replaced at the end of their service life. In order to facilitate the replacement and the handling of jammed paper, a part of the front frame 8 of the main body is replaced. Has a structure that can be opened and closed about the support shaft 9A.

  On the left side of FIG. 1, an electrical / control device 60 is housed. Above that, a fan 58 is provided, which exhausts air to prevent the temperature inside the machine from rising excessively. On the right side of the figure, another relatively small paper feeder 59 is provided. In this embodiment, the intermediate transfer belt 10 is used as an intermediate transfer member, but an intermediate transfer drum can also be used.

  Next, the detailed configuration and operation of the image forming apparatus configured as described above will be described. FIG. 2 is a block diagram showing the configuration of the electrical / control apparatus in the image forming apparatus 100 of FIG.

  A CPU (Central Processing Unit) 201 controls the entire image forming apparatus 100, and also performs image processing, index table generation, and the like. The CPU I / F 202 is connected to a memory arbiter (memory ARB) 203 and processes an I / F between the CPU 201 and the memory arbiter 203. The memory arbiter 203 controls access to the main memory 205 with the CPU 201, the communication control unit 209 and the DMA control unit 206 described below, and the like. The memory controller 204 controls the main memory 205 to read / write data. The main memory 205 stores various data such as a program of the CPU 201, an Index table, Index page data, CMYK page data, and CMYK page data after gradation processing.

  The DMA control unit 206 receives the image data of the CMYK page after gradation processing stored in the main memory 205 in synchronization with the printer engine 208 that performs image formation, and transfers the image data to the engine controller 207. The engine controller 207 controls the printer engine 208 for image formation. Further, the communication control unit 209 receives PDL data from a PC (personal computer) 210 connected via a network and transfers it to the main memory 205. The CPU 201 analyzes the PDL data and controls the ASIC 200 according to the obtained drawing information (drawing command).

  Next, the flow of image processing according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing a flow of image processing according to the embodiment of the present invention.

(1) The PDL storage unit 301 that is a PDL data storage area of the main memory 205 stores the PDL data sent from the communication control unit 209.

(2) The CPU 201 as the PDL analysis processing unit 302 in FIG. 3 reads the PDL data from the PDL storage unit 301, analyzes it, and includes color information (CMYK value; CMYK is a color value). Generate drawing commands.

(3) The generated drawing command is stored in the drawing command storage unit 303 which is a drawing command storage area of the main memory 205.

(4) The drawing unit of the CPU 201 receives a drawing command from the drawing command storage unit 303, and executes processing by the drawing preprocessing unit 304 and processing by the drawing processing unit 307 as shown in a flow shown in FIG. And an Index page are generated.

(5) The drawing preprocessing unit 304 of the CPU 201 receives a drawing command from the drawing command storage unit 303, generates an Index number and an Index table, and transfers the Index number to the drawing processing unit 307. Specifically, the index table generation processing unit 305 of the CPU 201 receives a drawing command from the drawing command storage unit 303, generates an index number as shown in FIG. 9 to be described later, and generates a CMYK drawing processing unit 308 and an index drawing process. The data is transferred to the unit 309.

(6) The main memory 205 as the Index table storage unit 306 stores the Index table transferred from the Index table generation processing unit 305. As shown in FIG. 4, the Index table is a table that associates Index values with color information corresponding to the Index values (CMYK values that are color values and attribute information A in this embodiment). As the Index value, as in the Index format of FIG. 6, the remaining value of the Index value that is not used as the Index number (0 to 250) is assigned as the attribute value. By doing so, the problem that the number of usable index numbers is reduced can be solved.

(7) The drawing processing unit 307 of the CPU 201 receives a drawing command from the drawing command storage unit 303, receives an Index value from the drawing preprocessing unit 304, and draws it in the Index page image storage unit 311 in the Index format of FIG. . If the Index value is not an Index number (Index table number) but an attribute value, the index value is rendered in the CMYK page image storage unit 310 in the CMYK format shown in FIG. Before describing this drawing process in detail, the configuration of the memory space in the main memory 205 and the data storage format in the main memory 205 for the Index page and the CMYK page will be described with reference to FIGS. FIG. 5 shows the configuration of the memory space in the main memory 205.

  In FIG. 5, a program area 500 stores a program executed by the CPU 201. The PDL data storage area 501 is an area for storing PDL data sent from the PC. The Index table storage area 502 corresponds to the Index table storage unit 306 in FIG. 3, and is an area for storing the Index table generated by the Index table generation processing unit 305. The index page storage area (index memory) 503 is an area for storing the index value of the page based on the data storage format illustrated in FIG. The CMYK page storage area (CMYK memory) 504 is an area for storing color value (CMYK) data based on the data storage format illustrated in FIG. The gradation-processed CMYK page storage area 505 is an area for storing gradation-processed CMYK data.

  FIG. 6 shows a data storage format (Index format) in the main memory 205 of the Index page. In this data storage format, it has an 8-bit Index value, and has a value (Index number) of 0 to 250 by a MOD operation modulo 251. Further, the values “255”, “254”, and “253” are not used as the index number but are used as attribute information, and when the pixel is “255”, it is a CMYK photographic image. “254” is used to indicate that it is a CMYK character image, and “253” is used to indicate that it is a CMYK graphics image.

  FIG. 7 shows a data storage format (CMYK format) in the main memory 205 of the CMYK page. As shown in the figure, C, M, Y, and K each have a format in which a 32-bit CMYK value consisting of 8 bits is stored. Note that the arrangement of data can be arbitrarily designed.

  From here, the drawing process by the drawing process part 307 of CPU201 is demonstrated with reference to the flowchart of FIGS.

  First, a description will be given with reference to FIG. First, the color information, the direct drawing number, and the total drawing number in the Index table are initialized to “0” (step S801). In addition, as an initial value of color information in the Index table, a numerical value that is not used as color information may be used.

  Subsequently, the following pre-drawing processing (step S802) and drawing processing (step S803) are executed for all drawing commands by the loop processing from step S802 to S804.

(Drawing pre-processing)
FIG. 9 shows a flow of the drawing pre-processing in step S802.

  First, the drawing command in the drawing command storage unit 303 in FIG. 3 is read (step S901).

  If it is determined in step S902 that the drawing command is a photographic image drawing command, the process proceeds to step S911, and the Index number is set to “255” indicating that it is a CMYK photographic image.

  On the other hand, if it is determined in step S902 that the drawing command is not a photographic image drawing command, the color information of the drawing command is read from the drawing command storage unit 303 in FIG. 3 (step S903).

Next, an index number is obtained by a hash function. Specifically, the color information read in step S903 is subjected to a MOD calculation (residue calculation) modulo a prime number “251” close to 255 which is the maximum value of 8 bits used in the Index format, and the remainder value is converted into an Index value. (Step S904). The remainder calculation here is performed as (R * 2 ²⁴ + G * 2 ¹⁶ + B * ⁸ + A)% 251. However, “*” is an operator for multiplication, and “%” is an operator for calculating a remainder (remainder of division). In general, the MOD calculation (residue calculation) is complicated, but the reciprocal number of “251” is prepared in advance, and the color information value (R * 2 ²⁴ + G * 2 ¹⁶ + B * ⁸ + A) is multiplied to obtain an integer. The remainder value is obtained by multiplying the converted value by “251” and obtaining the difference between the value and the color information value.

  Next, in step S905, it is checked whether the obtained index number has a value in the index number column of the index table. The determination that the Index number is not included is whether the “0” value (or a numerical value that is not used as color information) initialized in step S801 (FIG. 8) is included (that is, whether the index number remains in the initial state). ).

  If it is determined in step S905 that the index number obtained in step S904 is not used in the index table, the process proceeds to step S906, and the color information read in step S903 is set in the index table.

  If it is determined in step S905 that the index number obtained in step S904 is used in the index table, the process proceeds to step S907, and the color information in the index table corresponding to the index number obtained in step S904 is obtained. Determine whether the color is the same as the color drawn by the drawing command.

  If these pieces of color information are the same, the drawing preprocessing is terminated. On the other hand, if these pieces of color information are different, the process proceeds to step S908, and it is determined whether or not the drawing command is an instruction to draw a character. If the drawing command is a command for drawing a character (Yes in step S908), the index number is set to "254" (step S909). Otherwise (No in step S908), the index number is set. It is set to “253” (step S910), and this drawing pre-processing is terminated. As described above, the values “255”, “254”, and “253” are not used as the original index numbers but are used as attribute information. The pixel to be drawn or the object to be drawn is “255”. "" Indicates a CMYK photo image, "254" indicates a CMYK character image, and "253" indicates a CMYK graphics image.

(Drawing process)
FIG. 10 shows a flow of the drawing process in step S803.

  This drawing process is different depending on whether or not the Index number is less than “251”. Specifically, as shown in FIG. 10, when the Index number is less than “251” (Yes in Step S1001), the following drawing process (Step S1002) is performed, and the Index number is “251” or more. In the case (No in step S1001), the following Index & CMYK drawing process (step S1003) is performed.

(Index drawing process)
FIG. 11 shows a flow of the Index drawing process in step S1002.

  As shown in FIG. 11, the Index values are written to all the pixels in the Index page storage area 503 shown in FIG. 5 using the designated drawing command (Steps S1101 to S1102).

(Index & CMYK drawing process)
FIG. 12 shows a flow of the Index & CMYK drawing process in step S1003.

  As shown in FIG. 12, an Index value (any one of the above-mentioned 255, 254, or 253 according to the drawing command) is written to the Index page storage area 503 shown in FIG. 5 by the designated drawing command, and the CMYK page is stored. The CMYK value of the color information is written to the area 504 with the designated drawing command for all the pixels (steps S1201 to S1203).

(8) Returning now to FIG. The index value drawing processing described above is executed by the CPU 201 as the Index drawing processing unit 309 in FIG. The Index drawing processing unit 309 receives the drawing command from the drawing command storage unit 303, and draws the Index value set by the drawing preprocessing unit 304 in the Index page storage area 503 in FIG. 5 in the Index format in FIG.

The CMYK drawing processing unit 308 of the CPU 201 in (9) executes the Index & CMYK drawing processing shown in FIG. A photographic drawing command and a photographic image source image (color information (CMYK value)) are received from the drawing command storage unit 303, and a photographic image is drawn in the CMYK page storage area 504 as shown in the examples of FIGS. Note that since a photographic image basically has many colors, the index table generation process is not performed.

(10) The CMYK page storage area 504 of the main memory 205 serving as the CMYK page image storage unit 310 stores the CMYK page image drawn by the CMYK drawing processing unit 308.

(11) The Index page storage area 503 of the main memory 205 serving as the Index page image storage unit 311 stores the Index page image drawn by the Index drawing processing unit 309.

(12) The CPU 201 as the index table conversion processing unit 312 reads the index page image from the index page image storage unit 311 in units of pixels, converts the index values into CMYK values in the format of FIG. Forward.

(13) The CPU 201 as the switching processing unit 313 uses the CMYK value from the Index table conversion processing unit 312 and the CMYK value read in units of pixels from the CMYK page image storage unit 310 as the contents of the Index page image in (11) above. Switch with. Specifically, when the Index value of the Index page is an Index number of 0 to 250, the switching processing unit 313 outputs an input from the Index table conversion processing unit 312 and the Index value is “255” or “ In the case of “254” or “253”, the input from the CMYK page image storage unit 310 is output.

(14) The CPU 201 as the gradation processing unit 314 performs gradation processing on the data from the switching processing unit 313 and transfers the data to the CMYK page image storage unit 315 after gradation processing.

(15) The post-gradation-processed CMYK page storage area 505 of the main memory 205 serving as the post-gradation-process CMYK page image storage unit 315 is a floor on which the processing (12) to (14) has been performed in the image processing unit. The CMYK page image after tone adjustment is stored.

(16) The DMA control unit 206 in FIG. 2 as the DMA processing unit 316 reads the CMYK page image data after gradation processing from the CMYK page image storage unit 315 after gradation processing, and the printer engine 317 (208 in FIG. 2). Forward to.

(17) The printer engine 317 prints out based on the CMYK page image data after gradation processing.

  Here, drawing examples are shown in FIGS. FIG. 13 shows the result of the printout. As shown in FIG. 14, since the photographic image basically has a large number of colors, the photographic image is drawn in the CMYK page storage area 504 of the main memory 205 with the color values in the CMYK format of FIG. Since there are few, it draws in the Index page storage area 503 in the Index format of FIG. Further, when the color indicated by the color information of the drawing command and the color indicated by the color information registered in the Index table are the same, the character / graphics portion is drawn only with the Index value, so that the amount of data to be drawn is small and the drawing is performed. Processing speed can be increased.

(Second Configuration of Electrical / Control Device in Image Forming Apparatus 100)
Next, a second configuration of the electrical / control apparatus in the image forming apparatus 100 of FIG. 1 will be described with reference to FIGS. FIG. 15 is a block diagram showing a second configuration of the electrical / control apparatus in the image forming apparatus 100 of FIG. In the first configuration described above, the function of the image processing unit illustrated in FIG. 3 is realized by the CPU 201. However, in the second configuration, image processing that realizes the function of the image processing unit in FIG. The difference is that the unit 212 is provided in place of the DMA control unit 206. The other components are the same as those shown in FIG. 2, and the same components are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 16 shows a hardware configuration of the image processing unit 212 added to the ASIC 211 shown in FIG. Hereinafter, the configuration of the image processing unit 212 will be described with reference to FIG.

  The memory arbiter I / F 1601 arbitrates requests to the memory arbiter (memory ARB) of the image processing parameter reading unit 1602 and the Index / CMYK image reading unit 1608.

  The image processing parameter reading unit 1602 reads various parameters from the image processing parameter area of the main memory 205 shown in FIG. 15 via the memory arbiter I / F 1601 and sends them to the image processing parameter storage units denoted by reference numerals 1606 and 1607, which will be described later. Forward. The parameter address generation unit 1603 generates an address for reading various parameters from the image processing parameter area of the main memory 205 in FIG.

  The DMA parameter storage unit 1604 receives the bandwidth, band height, band start address, post-gradation CMYK bandwidth, post-gradation CMYK band height, C, M, Y received from the image processing parameter reading unit 1602. , K band start address and the like are stored. The Index table storage unit 1605 stores the Index table as shown in FIG. 4 and necessary for the Index value conversion unit 1612 generated by the Index table generation processing unit 305 of FIG.

  The halftone parameter storage unit 1606 stores a halftone parameter necessary for the gradation processing unit 1613 received from the image processing parameter reading unit 1602. The threshold matrix storage unit 1607 stores the threshold matrix necessary for the gradation processing unit 1613 received from the image processing parameter reading unit 1602.

  The Index / CMYK image reading unit 1608 reads the data of the Index page from the Index page storage area of the main memory 205 in FIG. 15 via the memory arbiter I / F 1601 and transfers it to the Index buffer unit 1609. Further, the CMYK page data is read from the CMYK page storage area of the main memory 205 and transferred to the CMYK buffer unit 1610. This may or may not be necessary for CMYK page data. However, depending on the case, it is inefficient to sequentially read the Index page data and the CMYK image, so the Index page data and the CMYK page data. Both are read simultaneously and stored in each buffer.

  The Index buffer unit 1609 stores Index page data for each of a plurality of pixels. The CMYK buffer unit 1610 stores CMYK page data for each of a plurality of pixels. The Index / CMYK image address generation unit 1611 reads Index page data and CMYK page data from the Index page storage area and the CMYK page storage area of the main memory 205 in FIG. 15 based on the parameters stored in the DMA parameter storage unit 1604. Generate an address for The Index value conversion unit 1612 reads Index page data from the Index buffer unit 1609 and further reads CMYK page data from the CMYK buffer unit 1610. Then, as shown below, the data is converted into CMYK values based on the Index page data and transferred to the gradation processing unit 1613.

  Here, FIG. 17 shows a processing flow in the Index value conversion unit 1612 of FIG. 16 and will be described.

  Index page data and CMYK page data are read for each pixel from the Index buffer unit 1609 and the CMYK buffer unit 1610, respectively (step S1701).

  Next, when the Index value read in pixel units is less than “251” (Yes in Step S1702), the process proceeds to Step S1703, the Index table is accessed with the Index value, and the corresponding CMYK value and attribute information A Is transferred to the gradation processing unit 1613.

  When the Index value read in pixel units is “254” (No in Step S1702 and Yes in Step S1704), the process proceeds to Step S1705, and the CMYK value corresponding to the pixel read in Step S1701 is set to the pixel. And A = character attribute, and the character attribute and CMYK value are sent to the gradation processing unit 1613.

  When the Index value read in pixel units is “253” (No in Step S1704 and Yes in Step S1706), the process proceeds to Step S1707, and the CMYK value corresponding to the pixel read in Step S1701 is set to the pixel. And the graphic attribute and CMYK value are transferred to the gradation processing unit 1613.

  When the Index value read in pixel units is “255” (No in Step S1706), the process proceeds to Step S1708, and the CMYK value corresponding to the pixel read in Step S1701 is set as the color of the pixel, and A = Used as a photo attribute, and transfers the photo attribute and CMYK value to the gradation processing unit 1613.

  Next, it is determined whether all the pixels have been processed (step S1709). If there is a pixel that has not been processed yet, the process returns to step S1701, and the above series of processing is repeated until all the pixels are processed. As described above, the processing by the index value conversion unit 1612 is performed.

  Returning to FIG. 16, the description will be continued. The gradation processing unit 1613 reads the threshold value matrix from the threshold value matrix storage unit 1607 and receives CMYK data and attribute information (attribute value) from the Index value conversion unit 1612, thereby performing gradation processing (halftone processing). And the data after gradation processing is transferred to the image buffer unit 1614 after image processing in units of words in the memory. The post-image processing image buffer unit 1614 temporarily stores a plurality of word data in order to perform a plurality of efficient burst transfers of the image data processed by the gradation processing unit 1613. Then, the image data is transferred from the image buffer 1616 after image processing to the engine controller 207 shown in FIG.

  In the example described above, the photographic image drawing and the character / graphics image drawing are separated, and the photographic image drawing is unconditionally treated as a color image in the CMYK format. However, even in the photographic image, it can be determined that the number of colors is small. In this case, the conversion processing to the Index table performed in the graphics image drawing may be performed. Here, CMYK is described as the color information, but CMY, RGB, and Lab colors can be similarly considered.

  In the present embodiment, the pixel format is expressed in an 8-bit Index format and a 32-bit CMYK format as shown in FIGS. The drawing area is composed of 8-bit planes, and in drawing in the Index format, only one plane is drawn with 8 bits / PIXEL. In other words, the entire image is not drawn with a 32-bit CMYK value. It can be fast. In addition, since no color reduction processing is required, high image quality can be maintained.

  In addition, as in Patent Document 2, when an Index table is created, the values of the Index table are not sequentially compared, but a hash function is used and the Index table is created with the key value, so the generation of the Index table is fast. It is. In addition, when the index table is accessed with a color key (index value) to be drawn at the time of drawing, and a collision occurs between the index table color and the key to be drawn, the color is a 32-bit color value (CMYK). Since drawing is performed, it is possible to draw correctly even if a key collision occurs, and this does not lead to a significant decrease in speed.

  FIG. 18 shows an example of an Index format in which attribute information is assigned in bit units. When 2 bits are assigned for attribute information, only 64 Index tables can be used in this way. In this case, since the Index table is small, many collisions occur in key generation using a hash function. When a key collision occurs, the color is drawn with a 32-bit color value, resulting in a decrease in processing speed.

  Therefore, in each of the embodiments of the present invention, an attribute value (attribute information) is not assigned in units of bits, but a value that is not used as an Index number (Index table number) is used as an attribute value, as in the Index format of FIG. By assigning, many index table numbers can be assigned to 8-bit values. Thereby, compared with the conventional case, the collision of the keys of the hash function can be reduced, and the drawing only in the Index format can be increased, so that the speed can be increased.

  Further, as in the Index table of FIG. 4, not only the color value (CMYK value) but also the attribute value (A) is registered in the Index table, and is registered in the Index table as the color information CMYKA, whereby the Index value conversion unit 1612 is registered. Thus, at the time of conversion, the attribute value obtained from the Index table is given to the gradation processing unit 1613, so that appropriate gradation processing can also be performed using the attribute value for the portion rendered in the Index format.

  The program for realizing the above-described processing flow executed by the image forming apparatus according to the present embodiment is configured to be provided by being incorporated in advance in a ROM or the like, but is a file in an installable or executable format. It can also be provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), and various memory cards.

  Further, the program executed by the image forming apparatus according to the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network.

  A program executed by the image forming apparatus according to the present embodiment has a module configuration including the above-described units (a drawing command generation unit, a drawing unit, and an image processing unit), and a CPU (processor) as actual hardware. By reading and executing the program from the storage medium, each unit is loaded onto the main storage device, and the drawing command generation unit, the drawing unit, and the image processing unit are generated on the main memory that is the main storage device. It has become.

  In the above embodiment, the image forming apparatus of the present invention will be described by taking an example in which the image forming apparatus is applied to a multifunction machine having at least two functions among a copy function, a printer function, a scanner function, and a facsimile function. The present invention can be applied to any image forming apparatus such as a printer, a scanner apparatus, and a facsimile apparatus.

100 Image forming apparatus 200, 211 ASIC
201 CPU
202 CPU I / F
203 Memory ARB
204 Memory Controller 205 Main Memory 206 DMA Controller 207 Engine Controller 208 Printer Engine 209 Communication Controller 210 PC
212 Image processing unit 301 PDL storage unit 302 PDL analysis processing unit 303 Drawing command storage unit 304 Pre-drawing processing unit 305 Index table generation processing unit 306 Index table storage unit 307 Drawing processing unit 308 CMYK drawing processing unit 309 Index drawing processing unit 310 CMYK Page image storage unit 311 Index page image storage unit 312 Index table conversion processing unit 313 Switching processing unit 314 Tone processing unit 315 Tone-processed CMYK page image storage unit 316 DMA processing unit 317 Printer engine

JP 2008-78820 A JP 2007-216675 A JP 2000-148973 A

Claims (6)

Drawing information generation means for analyzing input information and generating drawing information including color information;
Index number generation means for generating an Index number from the generated color information of the drawing information using a hash function;
Index unused determining means for determining whether the Index number generated by the Index number generating means is unused;
Index table storage means for storing a set of the Index number and the color information as an Index table when the Index unused determination means determines that the Index number is unused.
When the Index unused determination unit determines that the Index number has been used, the color information corresponding to the Index number stored in the Index table storage unit is acquired, and the color information is stored in the drawing Index color determining means for determining whether the color information is the same as the information color information,
Index number drawing means for drawing an Index number when the Index color determination means determines that the two color information are the same;
And Index data storing means for storing the Index number drawn by the Index number rendering means as Index value Index page,
Attribute information rendering means for rendering, on the Index page, a value indicating an attribute of an image to be rendered that is a value that is not used as an Index number when the Index color determination means determines that the two color information are different. ,
A drawing means for drawing a color value indicated by the color information of the drawing information when the Index color determining means determines that the two color information are different;
Image data storage means for storing image data composed of pages rendered by the rendering means;
The Index value stored in the Index data storage unit and the color information stored in the image data storage unit are read for each pixel. Based on the read Index value, the Index value of the value indicating the Index number is The color information stored in the image data storage means is used for the Index value of the value indicating the attribute of the image to be drawn, using the color information after conversion by converting the Index number into color information by accessing the Index table. Index value converting means for outputting image data composed of the color information using
An image processing apparatus comprising image processing means for performing image processing on the image data from the index value conversion means. Drawing information generation means for analyzing input information and generating drawing information including color information;
Index number generation means for generating an Index number from the generated color information of the drawing information using a hash function;
Index unused determining means for determining whether the Index number generated by the Index number generating means is unused;
An Index table that stores a set of the Index number and the color information including the attribute information of the image to be rendered as an Index table when the Index unused determination unit determines that the Index number is unused. Storage means;
When the Index unused determination unit determines that the Index number has been used, color information corresponding to the Index number stored in the Index table storage unit is acquired, and the color indicated by the color information is Index color determining means for determining whether the color is the same as the color indicated by the color information of the drawing information;
Drawing attribute determining means for determining whether or not an object to be drawn is drawn with a small number of colors from the drawing information and determining an attribute of a pixel to be drawn;
The drawing attribute determining means determines that the object to be drawn is drawn with a small number of colors, and the Index color determining means determines that the colors indicated by the two color information are the same. An index number drawing means for drawing the index number,
And Index data storing means for storing the Index number drawn by the Index number rendering means as Index value Index page,
Attribute information rendering means for rendering, on the Index page, a value indicating an attribute of an image to be rendered that is a value that is not used as an Index number when the Index color determination means determines that the two color information are different. ,
A drawing means for drawing a color value indicated by the color information of the drawing information when the Index color determining means determines that the two color information are different;
Image data storage means for storing image data composed of pages rendered by the rendering means;
The Index value stored in the Index data storage unit and the color information stored in the image data storage unit are read for each pixel. Based on the read Index value, the Index value of the value indicating the Index number is The color information stored in the image data storage means is used for the Index value of the value indicating the attribute of the image to be drawn, using the color information after conversion by converting the Index number into color information by accessing the Index table. Index value conversion means for outputting the image data using these color information and the attribute information determined by the drawing attribute determination means,
An image processing apparatus comprising: image processing means for performing image processing on the image data based on the attribute information using the image data and the attribute information from the Index value conversion means.   The image processing apparatus according to claim 2, wherein the drawing attribute determining unit determines that the drawn object is drawn with a small number of colors when the drawn object is a graphics image or a character image. .   The image processing apparatus according to claim 2, wherein the drawing attribute determining unit determines that the drawn object is drawn with a small number of colors when the drawn object is not a photographic image. An image processing method in an image processing apparatus,
A drawing information generation step of analyzing input information and generating drawing information including color information;
An index number generation step of generating an index number from the generated color information of the drawing information using a hash function;
An index unused determination step for determining whether the index number generated by the index number generation step is unused;
When the Index number is determined not to be used in the Index unused determination step, the Index number storage unit stores the Index number and the color information as an Index table. Index table storage step for storing a set of
When it is determined by the Index unused determination step that the Index number is already used, color information corresponding to the Index number stored in the Index table storage unit is acquired, and the color information is displayed in the drawing Index color determination step for determining whether the information is the same as the color information;
An Index number drawing step of drawing an Index number when it is determined by the Index color determination step that the two pieces of color information are the same;
The Index data storing means for storing the Index number drawn by the Index number drawing step as Index value Index page, and Index data storage step of storing the Index value of the Index page,
An attribute information drawing step of drawing, on the Index page, a value that is not used as an Index number and that indicates an attribute of an image to be drawn when the Index color determination step determines that the two color information are different. ,
A drawing step of drawing a color value indicated by the color information of the drawing information when the Index color determination step determines that the two color information are different;
An image data storage step for storing the image data in an image data storage means for storing image data composed of pages drawn by the drawing step;
The Index value stored in the Index data storage unit and the color information stored in the image data storage unit are read for each pixel. Based on the read Index value, the Index value of the value indicating the Index number is The color information stored in the image data storage means is used for the Index value of the value indicating the attribute of the image to be drawn, using the color information after conversion by converting the Index number into color information by accessing the Index table. Index value converting step for outputting image data composed of the color information using
And an image processing step of performing image processing on the image data from the Index value conversion step. An image processing method in an image processing apparatus,
A drawing information generation step of analyzing input information and generating drawing information including color information;
An index number generation step of generating an index number from the generated color information of the drawing information using a hash function;
An index unused determination step for determining whether the index number generated by the index number generation step is unused;
When the Index number is determined to be unused by the Index unused determination step, an Index table that stores a set of the Index number and the color information including the attribute information of the image to be rendered as an Index table. An index table storage step for storing a set of the index number and the color information including the attribute information of the image to be drawn in the storage means;
When it is determined by the Index unused determination step that the Index number is already used, color information corresponding to the Index number stored in the Index table storage unit is acquired, and the color indicated by the color information is Index color determination step for determining whether the color is the same as the color indicated by the color information of the drawing information;
A drawing attribute determining step of determining whether or not an object to be drawn is drawn with a small number of colors from the drawing information and determining an attribute of a pixel to be drawn;
The drawing attribute determining step determines that the object to be drawn is drawn with a small number of colors, and the Index color determining step determines that the colors indicated by the two color information are the same. An index number drawing step for drawing an index number,
And Index data storage step of storing the Index number drawn by the Index number drawing step as Index value Index page,
An attribute information drawing step of drawing, on the Index page, a value that is not used as an Index number and that indicates an attribute of an image to be drawn when the Index color determination step determines that the two color information are different. ,
A drawing step of drawing a color value indicated by the color information of the drawing information when the Index color determination step determines that the two color information are different;
An image data storage step for storing the image data in an image data storage means for storing image data composed of pages drawn by the drawing step;
The Index value stored in the Index data storage unit and the color information stored in the image data storage unit are read for each pixel. Based on the read Index value, the Index value of the value indicating the Index number is The color information stored in the image data storage means is used for the Index value of the value indicating the attribute of the image to be drawn, using the color information after conversion by converting the Index number into color information by accessing the Index table. Index value conversion step of outputting image data using these color information and attribute information determined by the drawing attribute determination step,
An image processing method comprising: an image processing step of performing image processing on the image data based on the attribute information using the image data and the attribute information from the Index value conversion step.

Images