JP2013056510A - Apparatus and method for image processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a drawing time.SOLUTION: An image forming apparatus carries out a command analysis processing (e.g., band initialization command processing, threshold value table setting command processing, etc.), a halftone pattern production processing, and a square shape drawing processing in parallel. Concretely, the image forming apparatus includes a drawing device 105 for performing the halftone pattern production processing in which a halftone pattern is produced by performing a gradation processing using a threshold value, and a square shape drawing processing in parallel.

Description

  The present invention relates to an image processing apparatus such as a copy, a scanner, a digital camera, and a printer, and more particularly to an image processing apparatus and an image processing method for analyzing, drawing, and printing captured commands.

  2. Description of the Related Art Conventionally, in a page printer or the like, there is a technique for drawing an image after gradation processing at high speed, for example, in order to meet a demand for increasing the printing speed while maintaining high resolution.

  The flow of processing in a conventional printer is, for example, generating an intermediate language that can be executed by a drawing apparatus by analyzing a PDL (Page Description Language) received from a network, and the drawing apparatus uses the intermediate language. Analyzes and renders the image after gradation processing to the band memory, encodes it with a binary image compression algorithm (JBIG, etc.), stores the code in the memory, and then delays each plate at the time of printout The code data is read from the memory, decoded by the above compression algorithm, and then C (Cyan: Cyan), M (Magenta: Magenta), Y (Yellow: Yellow), K (Key Plate) in the CMYK format. The data corresponding to each plate was transferred to the printer engine and printed.

  By the way, as a technique related to a technique for drawing an image after gradation processing at high speed, for example, binary matrix data binarized by gradation values is created in advance from halftone threshold matrix data and drawn. There is a conventional technique (hereinafter referred to as prior art 1) in which a halftone pattern having the least common multiple of the memory boundary width of a portion and the width of a basic bit pattern is created and sequentially drawn in the horizontal direction by a halftone repeat function. (See Patent Document 1).

  Further, as related to a technique for drawing an image after gradation processing at high speed, a halftone pattern having a drawing word X width is stored at least for the Y width of the halftone pattern, and a halftone pattern corresponding to the halftone pattern address value is stored. A technique for efficiently using a halftone pattern for a drawing object having the same gradation value by performing a cyclic shift process corresponding to the halftone pattern shift value using the tone pattern (hereinafter referred to as prior art 2). (See Patent Document 2).

  In Prior Art 1, for example, when a halftone pattern set command is received, halftone patterns after gradation processing are sequentially read from a designated halftone pattern head address. As described above, since the prior art 1 needs to read the halftone pattern before drawing, the drawing time is increased accordingly.

  Further, in the prior art 2, when a threshold table command set is received, the threshold table command set is not read sequentially for each drawing after reading sequentially from the head address of the specified threshold table command set. However, it is necessary to generate a halftone pattern by performing gradation processing for each drawing command using a threshold value table. In the prior art 2, since it is necessary to perform gradation processing for each drawing command using the threshold value table and generate a halftone pattern, the drawing time is increased accordingly.

  The present invention has been made in view of the above, and an object thereof is to provide an image processing apparatus and an image processing method capable of shortening the processing time.

  In order to solve the above-described problems and achieve the object, the present invention is an image processing apparatus that draws an image after gradation processing in a band unit indicating an area in a predetermined range, and decomposes the image into drawing units. A halftone threshold value storage means for storing a halftone threshold value of a halftone pattern having a drawing width that is a width between a start point and an end point in a horizontal direction in the case of at least the vertical width of the halftone pattern; A halftone pattern storage means for storing a halftone pattern of width at least for the vertical width of the halftone pattern, and a value indicating a vertical position of a horizontal line to be drawn, the corresponding halftone pattern is stored. Halftone pattern address generating means for generating a halftone pattern address value of the halftone pattern storage means; and The halftone threshold value is read from the halftone threshold value storage means, gradation processing is performed using the read halftone threshold value, and the halftone pattern generated by the gradation processing is transferred to the halftone pattern storage means. A halftone pattern generating means for calculating a remainder value obtained by dividing the drawing width by a width in the horizontal direction of the halftone pattern, and using the remainder value, the halftone pattern stored in the halftone pattern storage means A halftone pattern shift value generating means for generating a halftone pattern shift value for shifting the tone pattern, and a halftone pattern transferred from the halftone pattern storage means by the access by the halftone pattern address value. For tone pattern shift value generation means A cyclic shift means for performing a cyclic shift by the halftone pattern shift value using the generated halftone pattern shift value, and a halftone pattern corresponding to a drawing object having the same gradation value by the cyclic shift. And a drawing unit that repeatedly draws, and the processing by the halftone pattern generation unit and the processing by the drawing unit are performed in parallel.

  The present invention also relates to an image processing method executed by an image processing apparatus that draws an image after gradation processing in units of bands indicating a predetermined range area, in the horizontal direction when the image is decomposed into drawing units. The halftone threshold value is read from the halftone threshold value storage means for storing the halftone threshold value of the halftone pattern of the drawing width which is the width between the start point and the end point at least for the vertical width of the halftone pattern. Then, gradation processing is performed using the read halftone threshold value, and the halftone pattern generated by the gradation processing is stored for at least the halftone pattern of the drawing width in the vertical width of the halftone pattern. A halftone pattern generation process to be transferred to the halftone pattern storage means and a vertical position of a horizontal line to be drawn are shown. From the halftone pattern address generating means for generating the halftone pattern address value of the halftone pattern storage means storing the corresponding halftone pattern, and the drawing width divided by the horizontal width of the halftone pattern A halftone pattern shift value generating step for generating a halftone pattern shift value for shifting the halftone pattern stored in the halftone pattern storage means using the remainder value, A halftone pattern transferred from the halftone pattern storage means by access by a halftone pattern address value is converted into the halftone pattern using the halftone pattern shift value generated by the halftone pattern shift value generation step. A halftone pattern generating step, and a halftone pattern generating step, wherein a halftone pattern corresponding to a rendering object having the same gradation value is repeatedly drawn by the cyclic shift, and the halftone pattern is drawn. And the drawing process are performed in parallel.

  According to the present invention, there is an effect of shortening the drawing time.

FIG. 1 is a diagram illustrating a configuration example of a mechanism unit of an image forming apparatus (referred to as a color printer) to which the image processing apparatus according to the present embodiment can be applied. FIG. 2 is a diagram illustrating an example of a hardware configuration of the electrical / control unit of the image forming apparatus 100. FIG. 3 is a flowchart showing an outline of an example of processing in the image forming apparatus 100. FIG. 4 is a block diagram illustrating a configuration example of the drawing apparatus 105. FIG. 5 is a block diagram illustrating a configuration example of the drawing processing device 123. FIG. 6 is a block diagram illustrating a configuration example of the horizontal line drawing device 136. FIG. 7 is a diagram illustrating a format example of a drawing parameter setting command. FIG. 8 is a diagram illustrating a format example of a drawing execution command. FIG. 9 is a flowchart illustrating an example of the drawing process. FIG. 10 is a flowchart illustrating an example of the parameter setting process. FIG. 11 is a flowchart illustrating an example of halftone pattern generation processing. FIG. 12 is a diagram illustrating an example of a command. FIG. 13 is a diagram illustrating an example of band drawing. FIG. 14 is a diagram comparing the band drawing processing time according to the command of FIG. 12 with the band drawing processing time according to the present embodiment.

  Hereinafter, an embodiment of an image processing apparatus and an image processing method will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration example of a mechanism unit of an image forming apparatus (referred to as a color printer) to which the image processing apparatus according to the present embodiment can be applied. In the image forming apparatus 100 shown in FIG. 1, a belt-like photosensitive member 1 as an image carrier is rotatably supported by rotating rollers 2 and 3, and the direction of the arrow A is driven by the rotating rollers 2 and 3. Is rotated. A charging device 4 that is a charging unit, a static elimination lamp L, and a cleaning blade 15 </ b> A for the photosensitive member 1 are disposed on the outer peripheral portion of the photosensitive member 1. A laser writing unit 5 serving as an optical writing unit is disposed at a downstream position of the charging device 4.

  Above the laser writing unit 5, there is disposed a multicolor developing device 6 in which a plurality of developing units (developing means) are supported in a switchable manner. 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 position where development is possible 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 direction indicated by the arrow B. 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, there are cleaning blades 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).

  The unitized process cartridge 31 incorporates the photosensitive member 1, the charging device 4, the intermediate transfer belt 10, the cleaning device 16, and a conveyance guide 30 that forms a sheet conveyance path, and can be replaced when the end of its life is reached. It is configured as follows. 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.

  A controller board 60 is housed on the left side of FIG. 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.

  FIG. 2 is a diagram illustrating an example of a hardware configuration of the electrical / control unit of the image forming apparatus 100. 2, the controller board 60 is connected to a personal computer (hereinafter referred to as “PC”) 200 via a network. The controller board 60 includes a CPU 101, a CPU I / F 102, a memory arbiter 103, a memory controller 104, a drawing device 105 including hardware circuits, an engine controller 106, a communication controller 107, and a local I / F 108. A ROM 109 and a panel controller 110.

  The CPU 101 controls the entire image forming apparatus 100. The CPU 101 also analyzes a PDL (page description language) transmitted from the PC 200, and generates a drawing command and information necessary for image processing. Here, PDL is illustrated as an example of image drawing instruction data described in a predetermined language and instructing image drawing. However, the present invention is not limited to this. The CPU I / F 102 is an interface of the CPU 101 and is connected to the main memory 112 and other controllers via the memory arbiter 103. The main memory 112 has a halftone process after a predetermined halftone process is performed on various data obtained by analyzing the PDL and PDL, and an image included in the PDL (image data obtained by analyzing the PDL). Stores image data (halftone pattern), a computer program executed by the CPU 101, and the like.

  The memory arbiter 103 performs arbitration between the memory controller 104 and various controllers. The memory controller 104 controls the main memory 112 and is connected to various controllers and the CPU 101 via the memory arbiter 103.

  The drawing device 105 reads and analyzes the drawing command generated by the CPU 101, and executes drawing processing for each band according to the analyzed command. Then, the drawn band image is written in the band memory area of the main memory 112. The engine controller 106 controls the printer engine 114. The printer engine 114 forms an image on a medium under the control of the engine controller 106. The PC 200 creates an image PDL to be output to the printer engine 114, and outputs the PDL to the image forming apparatus 100 via a network.

  The communication controller 107 is connected to the network and receives data, commands, and the like transmitted from the PC 200 or the like connected via the network. The communication controller 107 also outputs received data and the like to each controller connected via the memory arbiter 103, and transmits data and the like input from each controller to the PC 200 and the like.

  The ROM 109 stores computer programs executed by the CPU 101, character font information, and the like. The ROM 109 is connected to the memory arbiter 103 via the local I / F 108. The panel controller 110 controls the operation panel 113. The panel controller 110 is connected to the memory arbiter 103 via the local I / F 108. The panel 113 displays the state of the image forming apparatus 100 and accepts an operation input from the user for the image forming apparatus 100.

  FIG. 3 is a flowchart showing an outline of an example of processing in the image forming apparatus 100. In the PDL storage step S <b> 1, the PDL input from the PC 200 is stored in the main memory 112. In the next drawing command generation step S2, the CPU 101 reads and analyzes the PDL stored in the main memory 112, and generates a drawing command. Further, the CPU 101 executes halftone processing on the image obtained by analyzing the PDL, and stores the image data (halftone pattern) after the halftone processing in a predetermined area (halftone pattern storage area) of the main memory 112. ). In the next drawing command storage step S <b> 3, the CPU 101 writes the generated drawing command in a predetermined area of the main memory 112. In the next drawing processing step S4, the drawing apparatus 105 reads the drawing command stored in the main memory 112, and executes drawing of the image in band units in accordance with the read drawing command. The CPU 101 writes the drawn band image in the main memory, and the band image for one page is stored in the main memory 112 (next page storage step S5). Next, the printer engine 114 reads the image data for one page drawn by the drawing device 105 from the main memory 112, prints it, and outputs it.

  FIG. 4 is a block diagram illustrating a configuration example of the drawing apparatus 105. As illustrated in FIG. 4, the drawing device 105 includes a memory arbiter I / F 121, a command analysis device 122, a drawing processing device 123, and a controller 124. The memory arbiter I / F 121 is an interface device for connecting the command analysis device 122 and the drawing processing device 123 to the memory arbiter 103.

  The command analysis device 122 reads the drawing command stored in the main memory 112 and analyzes the read drawing command. If the read command is a drawing parameter setting command, the command analysis device 122 transfers various parameters specified by the command to the drawing processing device 123 and reads the next command from the main memory 112. On the other hand, if the read command is a drawing execution command, various parameters specified by the command are transferred to the drawing processing device 123, and then a drawing activation signal is transferred. Thereafter, when receiving a drawing end signal from the drawing processing device 123, the command analysis device 122 reads the next drawing command from the main memory 112. In addition, when the command analysis device 122 reads a band initialization command that is the head command of the drawing command, the band parameters (for example, the band head address, the band start point Y coordinate, the band height) specified by the band initialization command are read out. , Bandwidth, etc.) is transferred to the drawing processor 123, and the next command is read from the main memory 112.

  When the drawing processing device 123 receives various parameters (drawing parameters for drawing) from the command analysis device 122 and receives a drawing activation signal from the command analysis device 122, the drawing processing device 123 executes the drawing processing. In addition, when the drawing processing ends, the drawing processing device 123 transfers an end signal indicating the end of the drawing processing to the command analysis device 122. The detailed configuration of the drawing processing device 123 will be described later. The controller 124 is means for controlling the entire drawing apparatus 105.

  FIG. 5 is a block diagram illustrating a configuration example of the drawing processing device 123. As shown in FIG. 5, the drawing processing device 123 includes a DMA address generating device 131, a DMA reading device 132, a band parameter storage device 133, a graphics drawing parameter storage device 134, a horizontal line conversion device 135, A horizontal line drawing device 136, a graphics threshold value matrix storage device 137, and a controller 138 are included.

  The DMA address generation device 131 receives the start address of each DMA (including graphics image threshold start address) such as parameters for drawing from the command analysis device 122, generates a DMA address, and reads the DMA address. Transfer to 132. When the DMA reading device 132 receives the head address of each DMA from the DMA address generation device 131, the DMA reading device 132 accesses the main memory 112 via the memory arbiter I / F 121, and is specified by the head address of each DMA from the main memory 112. DMA data stored in the memory area is read and stored in the graphics threshold value matrix storage device 137. The graphics threshold matrix storage device 137 stores the DMA threshold matrix data. The graphics drawing parameter storage device 134 stores the graphics drawing parameters transferred from the command analysis device 122. The band parameter storage device 133 stores the band parameter transferred from the command analysis device 122. The horizontal line conversion device 135 reads the drawing parameters stored in the graphics drawing parameter storage device 134, and converts the read drawing parameters into horizontal line data. The horizontal line data includes a horizontal line Y value, a horizontal line X start point value, and a horizontal line X end point value. The horizontal line drawing device 136 draws in the band memory area of the main memory 112 via the memory arbiter I / F 121 based on the horizontal line data from the horizontal line conversion device 135.

  FIG. 6 is a block diagram illustrating a configuration example of the horizontal line drawing device 136. As shown in FIG. 6, the horizontal line drawing device 136 includes a halftone pattern address generation device 141, an X start point word value generation device 142, an X end point word value generation device 143, a drawing word X value generation device 144, Halftone pattern shift value generation device 145, drawing mask generation device 146, halftone pattern storage device 147, cyclic shift device 148, logical operation device 149, drawing address generation device 150, and halftone pattern generation device 151 A halftone threshold address generation device 152 and a horizontal drawing controller 153.

  The halftone pattern address generator 141 uses the horizontal line Y value transferred from the horizontal line converter 135 and the Y direction (vertical direction) width (Y width) of the halftone pattern read by the DMA reader 132. , Horizontal line Y value-MOD-halftone pattern Y width (performs MOD operation to divide horizontal line Y value by halftone pattern Y width) to obtain the Y value of the halftone pattern which is the remainder of division. Transfer to the halftone pattern storage device 147 as the tone pattern address.

  The X start point word value generation unit 142 obtains a drawing word X start point value for each drawing word from the horizontal line X start point value transferred from the horizontal line conversion unit 135 and transfers the drawing word X start point value to the drawing word X value generation unit 144.

  The X end point word value generation device 143 obtains a drawing word X end point value for each drawing word from the horizontal line X end point value transferred from the horizontal line conversion device 135 and transfers it to the drawing word X value generation device 144.

  The drawing word X value generation device 144 generates the drawing word X value of the X end point value from the X start point value in units of drawing words, and transfers it to the halftone pattern shift value generation device 145. The drawing word X value is the width between the start point and end point in the horizontal direction when the image is decomposed into drawing units.

  The halftone pattern shift value generation device 145 calculates the drawing word X value transferred from the drawing word X value generation device 144 and the width in the X direction (X width) of the halftone pattern read by the DMA reading device 132. The drawing word X value-MOD-halftone pattern X width is calculated, the X value of the halftone pattern which is the remainder of the division is obtained, and transferred to the cyclic shift device 148 as the halftone pattern shift value.

  The drawing mask generation device 146 generates a drawing mask from the X start point to the X end point for each drawing word from the horizontal line X start point value and the horizontal line X end point value transferred from the horizontal line conversion device 135, and the logical operation device 149. Forward to.

  The halftone pattern storage device 147 is a storage device that stores horizontal lines of halftone pattern drawing words for the Y width of the halftone pattern, and is accessed by the halftone pattern address from the halftone pattern address generation device 141. The halftone pattern value is transferred to the cyclic shift device 148.

  The cyclic shift unit 148 receives a halftone pattern value from the halftone pattern storage unit 147, a halftone pattern shift value from the halftone pattern shift value generation unit 145, and a halftone pattern value from the drawing parameter storage unit 134. The tone pattern value is cyclically shifted, and the halftone pattern value after the cyclic shift is transferred to the logical operation device 149.

  The logical operation device 149 is configured by an AND circuit, and generates a drawing pattern value by obtaining a logical product of the halftone pattern value after the cyclic shift from the cyclic shift device 148 and the drawing mask from the drawing mask generation device 146. Then, the generated drawing pattern value is transferred to the memory arbiter I / F 121.

  The drawing address generation device 150 generates a drawing address that is an address for drawing in the band memory of the main memory 112 from the horizontal line Y value and the horizontal line X start point value from the horizontal line conversion device 135 and transfers them to the memory arbiter I / F 121. To do. The horizontal drawing controller 153 controls the entire horizontal line drawing device 136.

  The halftone pattern generation device 151 is activated after receiving the drawing execution command (see FIG. 8), reads the threshold value from the specified threshold value table address of the graphics threshold value matrix storage device 137, and sets the color. The gradation processing is performed with the value, and the halftone pattern after the gradation processing is stored in the halftone pattern storage device 147.

  The halftone threshold address generation device 152 is activated after receiving the drawing parameter setting command (see FIG. 7), and starts from the specified threshold table address of the graphics threshold matrix storage device 137. Generate an address for

  The horizontal drawing controller 153 controls the entire processing operation performed by the horizontal line drawing device 136.

  FIG. 7 is a diagram illustrating a format example of a drawing parameter setting command. FIG. 8 is a diagram illustrating a format example of a drawing execution command. Drawing commands can be divided into drawing parameter setting commands shown in FIG. 7 and drawing execution commands shown in FIG.

  FIG. 7 shows a band initialization command (1), a threshold table setting command (2), and a band end command (3).

  The band initialization command (1) shown in FIG. 7 is a command for defining the start address of the band, the height and width of the band. When the command analysis device 122 shown in FIG. 4 receives this command, it stores the start address of the band and the height and width of the band.

  The threshold value table setting command (2) shown in FIG. 7 is a command for setting a halftone threshold value. Upon receiving this command, the command analysis device 122 shown in FIG. 4 sets a (graphics image) threshold start address, and starts the DMA address generation device 131 and the DMA reading device 132 shown in FIG. The specified threshold values are sequentially read from the drawing command area of the main memory 112 shown in FIG. 2 and written into the graphics threshold value matrix storage device 137 shown in FIG. Further, the command analysis device 122 shown in FIG. 4 stores the dither X and Y sizes in the graphics drawing parameter storage device 134 shown in FIG. The halftone threshold value is a threshold matrix value for halftone processing for converting a multivalued image into a small value (binary / 4 value, etc.). When the threshold matrix of the systematic dither method is roughly classified from the spatial frequency characteristics, the dot concentration type configured to gradually increase the center and the dot dispersion type configured to disperse the dots as much as possible. Classified into species. The dither X and Y sizes indicate the size in the X direction and the size in the Y direction of the halftone threshold value (threshold matrix).

  The band end command (3) shown in FIG. 7 is a command for ending the drawing process of the defined band. Upon receiving this command, the command analysis device 122 shown in FIG. 4 ends the drawing process for the band.

  FIG. 8 shows a rectangle drawing command (1) and a triangle drawing command (2).

  The rectangle drawing command (1) shown in FIG. 8 is a command for drawing a rectangle from the upper left coordinate to the lower right coordinate of the designated rectangle. When receiving this command, the command analysis device 122 shown in FIG. 4 stores the upper left coordinates of the rectangle, the lower right coordinates, and the rectangle command name in the graphics drawing parameter storage device 134 shown in FIG. 4 is activated.

  The triangle drawing command (2) shown in FIG. 8 is a command for drawing a triangle from the apex of the specified triangle. Upon receiving this command, the command analysis device 122 shown in FIG. 4 stores the coordinates of the triangle vertices in the graphics drawing parameter storage device 134 and activates the drawing processing device 123 shown in FIG.

  FIG. 9 is a flowchart illustrating an example of the drawing process. FIG. 9 shows an example of a drawing process performed by the drawing apparatus 105 shown in FIG.

  As shown in FIG. 9, the drawing apparatus 105 reads a drawing command (S101). Subsequently, the drawing apparatus 105 determines whether or not the read drawing command is a drawing execution command (rectangular drawing command, OR, triangle drawing command, see FIG. 8) (S102).

  If it is determined that the command is a drawing execution command (S102, Yes), the drawing device 105 sets drawing parameters in the graphics drawing parameter storage device 134 (S103). The graphics drawing parameter storage device 134 may be configured as a double buffer so that the drawing parameters of the drawing process being executed are stored on one side and the drawing parameters for the next drawing are stored on the other side. it can.

  Subsequently, the drawing device 105 determines whether or not the color value set by the drawing execution command is the same as the color value of the halftone pattern storage device 147 (S104).

  If the halftone pattern color values are different as a result of the determination (S104, No), the drawing apparatus 105 executes a halftone pattern generation process (see FIG. 11) (S105), and proceeds to the process of step S106. . On the other hand, as a result of the determination, if the color values of the halftone patterns are the same (S104, Yes), the drawing apparatus 105 proceeds to the process of step S106 without executing the halftone pattern generation process. Note that the halftone pattern storage device 147 can be configured as a double buffer so that the halftone pattern at the time of drawing is stored on one side and the halftone pattern at the time of the next drawing is stored on the other side.

  Subsequently, the drawing apparatus 105 determines whether or not drawing is currently being performed (drawing processing is being executed) (S106).

  If the result of the determination is that drawing is being performed (drawing process is being executed) (Yes in S106), the drawing apparatus 105 waits until drawing is completed (S107), and after drawing is completed, the process proceeds to S108. On the other hand, if the result of determination is that drawing is not being performed (drawing process is being executed) (No at S106), the drawing apparatus 105 proceeds to the process of S108 as it is.

  Subsequently, when the drawing processing is completed, the drawing device 105 switches the drawing parameter storage device for graphics 134 and the halftone pattern storage device 147 to parameters for drawing, generates an activation signal, and activates the drawing processing device 123. (S108), the process returns to step S101 described above.

  If the result of determination in step S102 is not a drawing execution command (S102, No), the drawing apparatus 105 determines whether or not it is a drawing end command (see (3) in FIG. 7). Determination is made (S109). If the result of determination is not a drawing end command (S109, No), the drawing apparatus 105 executes parameter setting processing (see FIG. 10) (S110), and returns to step S101 described above. On the other hand, if the result of the determination is a drawing end command (S109, Yes), the drawing apparatus 105 ends the drawing process, notifies the CPU 101 of the end of the drawing process, and ends the process.

  As described above, in FIG. 9, by performing the cyclic shift process for the halftone pattern shift value using the halftone pattern corresponding to the halftone pattern address value, the drawing objects having the same gradation value are processed. While the drawing process is efficiently performed using the halftone pattern, the halftone pattern is generated for the drawing object having the gradation value in parallel with the drawing process being executed.

  FIG. 10 is a flowchart illustrating an example of the parameter setting process. As shown in FIG. 10, the drawing apparatus 105 determines whether or not the drawing command read in S101 of FIG. 9 described above is a band initialization command (S201).

  As a result of the determination, if the drawing command is not a band initialization command (S201, Yes), the drawing apparatus 105 assumes that the drawing command is a threshold table setting command (see (2) in FIG. 7). The threshold value of the drawing area stored in the main memory 112 is sequentially read from the (graphics image) threshold value leading address of the command parameter, and the read threshold value is stored in the graphics threshold value matrix. Writing to the device 137 (S202).

  If the drawing command is a band initialization command as a result of the determination (S201, Yes), the drawing device 105 writes the command parameter of the band initialization command in the band parameter storage device 133 (S203).

  The drawing apparatus 105 returns to step S101 of FIG. 9 described above after the processing of step S202 or step S203.

  FIG. 11 is a flowchart illustrating an example of halftone pattern generation processing. FIG. 11 shows a process of generating a halftone pattern by generating one bit after gradation processing using the threshold values of the dither X-direction and Y-direction sizes using the color values of the drawing command. As shown in FIG. 11, the drawing apparatus 105 sets IY = 0 (S301) and IX = 0 (S302), and the values of [IY] and [IX] in the threshold value table are less than the color values. It is determined whether or not there is (303).

  As a result of the determination, if the values of [IY] and [IX] in the threshold value table are less than the color value (S303, Yes), the drawing apparatus 105 determines the halftone patterns [IY] and [IX]. = 1 (S304). On the other hand, as a result of the determination, if the values of [IY] and [IX] in the threshold value table are not less than the color value (S303, No), the drawing apparatus 105 determines that the halftone patterns [IY] and [IY] IX] = 0 (S305).

  Subsequently, the drawing apparatus 105 sets IX = IX + 1 (S306), and determines whether or not the size of IX is less than the dither X size (the size of the dither in the X direction) (S307).

  As a result of the determination, if the size of IX is smaller than the dither X size (S307, Yes), the drawing apparatus 105 returns to S303 described above. On the other hand, if the result of determination is that the size of IX is not less than the dither X size (S307, No), the drawing apparatus 105 sets IY = IY + 1 (S308), and the IY size is dither Y size (dither size). It is determined whether or not it is less than the size in the Y direction (S309).

  If the result of determination is that the IY size is less than the dither Y size (S309, Yes), the drawing apparatus 105 returns to S302 described above. On the other hand, if the result of determination is that the IY size is not less than the dither Y size (S309, No), the drawing apparatus 105 returns to step S106 of FIG. 9 described above.

  Note that FIG. 11 shows processing when the bit after gradation processing is 1 bit, but the same can be considered when the bit after gradation processing is 2 bits or 4 bits.

  FIG. 12 is a diagram illustrating an example of a command. FIG. 13 is a diagram illustrating an example of band drawing. FIG. 14 is a diagram comparing the band drawing processing time according to the command of FIG. 12 with the band drawing processing time according to the present embodiment.

  The band initialization command of command (1) shown in FIG. 12 is a drawing parameter setting command. In the band initialization command, for example, the drawing band start address, the upper left starting point Y coordinate of the drawing band, the height of the drawing band, and the width of the drawing band are set (for example, (1) in FIG. 7). Etc.)

  The halftone pattern set command of command (1) shown in FIG. 12 is a drawing parameter setting command. In the halftone pattern set command, for example, the size of the dither in the X and Y directions and the halftone head address are set. The halftone pattern head address is an address for specifying the storage location of the halftone pattern after gradation processing in the main memory 112. Note that the halftone pattern after gradation processing is generated in the X-direction and Y-direction sizes of the dither for each color value used in the software by the above-described drawing command generation step S2 shown in FIG.

  The rectangle drawing command of command (1) shown in FIG. 12 is a drawing execution command for instructing drawing of a rectangle. In the rectangle drawing command shown in FIG. 12, for example, the coordinates of the upper left and lower right vertices of the page coordinate rectangle are set in the band area of the main memory 112 (see, for example, (1) in FIG. 8). For example, in the rectangular drawing command of command (1) in FIG. 12, three colors are set by the halftone pattern set command.

  The band end command of command (1) shown in FIG. 12 is a command for ending the drawing processing of the defined band.

  The band initialization command of command (2) shown in FIG. 12 is a drawing parameter setting command. In the band initialization command, for example, the drawing band start address, the upper left starting point Y coordinate of the drawing band, the height of the drawing band, and the width of the drawing band are set (for example, (1) in FIG. 7). Etc.)

  The threshold value table set command of command (2) shown in FIG. 12 is a drawing parameter setting command. In the threshold table set command, the dither size in the X and Y directions and the threshold table head address are set (for example, see (2) in FIG. 7). The threshold table head address is an address for specifying the storage location of the graphics dither threshold in the main memory 112. The threshold value of the graphics dither has a dither size, and the drawing device 105 generates a halftone pattern after gradation processing based on the color value specified by the drawing command.

  The quadrangle drawing command of command (2) shown in FIG. 12 is a drawing execution command for instructing drawing of a rectangle. The band end command of command (2) shown in FIG. 12 is a command for ending the drawing process of the defined band.

  The drawing apparatus 105 reads a drawing command (commands (1) and (2) shown in FIG. 12) from the main memory 112, and executes drawing processing according to the read command.

  For example, when the command (1) shown in FIG. 12 is read, the drawing apparatus 105 first reads a band initialization command and specifies a band on which drawing is performed. Subsequently, the drawing apparatus 105 reads the halftone pattern set command (1), and reads the halftone pattern after gradation processing corresponding to the band from the main memory 112. Subsequently, the drawing apparatus 105 reads a rectangle drawing command (1) for instructing drawing of a rectangle, and executes a rectangle drawing process. The drawing apparatus 105 repeats the above processing until the reading of the band end command is performed, and when the reading of the band end command is performed, the drawing processing is ended.

  As described above, in the drawing process using the command (1) shown in FIG. 12, when the halftone pattern set command (1) is received, the drawing apparatus 105 performs the gradation process from the designated halftone pattern start address. The halftone patterns are read sequentially. As described above, in the drawing process by the command (1) shown in FIG. 12, it is necessary to read the halftone pattern before drawing every time drawing is performed, so that the drawing time is increased accordingly. Although not shown in FIG. 12, since it is necessary to generate a halftone pattern by gradation processing, the software processing time is increased accordingly.

  When the command (2) shown in FIG. 12 is read, the drawing apparatus 105 first reads the band initialization command and identifies the band on which drawing is performed. Subsequently, the drawing apparatus 105 reads the threshold value table set command (1), and reads quadrilateral drawing commands (1), (2), (3), and (3) instructing quadrilateral drawing. Subsequently, the drawing apparatus 105 performs gradation processing using a threshold value table for each quadrilateral drawing command to generate a halftone pattern. Subsequently, as shown in FIG. 13, the drawing apparatus 105 executes a quadrangular drawing process using the halftone pattern. Subsequently, when the drawing apparatus 105 reads the band end command, the drawing apparatus 105 ends the drawing process.

  As described above, in the drawing process using the command (2) shown in FIG. 12, when the threshold value table command set (1) is received, the drawing apparatus 105 starts from the head address of the designated threshold value table command set. Sequential reading is not performed for each drawing as in command (1) shown in FIG. As described above, the command (2) shown in FIG. 12 does not read the threshold table command set for each drawing, but uses the threshold table to perform gradation processing for each drawing command. A halftone pattern needs to be generated. Therefore, in the drawing process using the command (2) shown in FIG. 12, since it is not necessary to generate a halftone pattern for each color value used in the software, the processing time of the software is reduced. Every time, a halftone pattern is generated by hardware, so that the drawing time becomes long.

  On the other hand, as shown in FIG. 14, in the embodiment described above, for example, when processing by the command (2) shown in FIG. 12 is performed, command analysis processing (for example, band initialization command processing, threshold value) Table set command processing), halftone pattern generation processing, quadrilateral drawing processing, etc. are performed in parallel. Specifically, halftone pattern generation processing for generating a halftone pattern by performing gradation processing using a threshold value table and quadrilateral drawing processing are performed in parallel. As described above, according to the above-described embodiment, the halftone pattern generation process and the drawing process are processed in parallel. Therefore, the drawing time can be shortened by the amount that the halftone pattern generation process does not appear in the table. it can. Note that, according to the above-described embodiment, when processing by the command (2) shown in FIG. 12 is performed, a halftone pattern is generated for each color value used in the software in the drawing command generation step S2 shown in FIG. Since it is not necessary to perform processing, the drawing time can be shortened as much as the software processing time can be reduced.

  In the above-described embodiment, the graphics drawing parameter storage device 134 and the halftone pattern storage device 147 are used as a double buffer, so that data for drawing processing (drawing parameters and halftone pattern) being executed on one surface is performed. And the next drawing data can be stored on the other side, so that the drawing process can be smoothed and the drawing time can be shortened.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 103 Memory arbiter 104 Memory controller 105 Drawing apparatus 106 Engine controller 107 Communication controller 108 Local I / F
109 ROM
110 Panel Controller 112 Main Memory 113 Panel 114 Printer Engine 122 Command Analysis Device 123 Drawing Processing Device 124 Controller 131 DMA Address Generation Device 132 DMA Reading Device 133 Band Parameter Storage Device 134 Graphics Drawing Parameter Storage Device 135 Horizontal Line Conversion Device 136 Horizontal Line drawing device 137 Graphics threshold value matrix storage device 141 Halftone pattern address generation device 142 X start point word value generation device 143 X end point word value generation device 144 Drawing word X value generation device 145 Halftone pattern shift value generation device 146 Drawing mask generation device 147 Halftone pattern storage device 148 Cyclic shift device 149 Logic operation device 150 Les generator 151 halftone pattern generator 152 halftone threshold address generator 153 horizontal drawing controller

Japanese Patent No. 3446324 Japanese Patent No. 4490783

Claims (3)

An image processing apparatus that draws an image after gradation processing in band units indicating a predetermined range area,
Halftone threshold that stores the halftone threshold value of the halftone pattern of the drawing width, which is the width between the start and end points in the horizontal direction when the image is divided into drawing units, at least for the vertical width of the halftone pattern Value storage means;
Halftone pattern storage means for storing the halftone pattern of the drawing width by at least the vertical width of the halftone pattern;
Halftone pattern address generating means for generating a halftone pattern address value of the halftone pattern storage means storing the corresponding halftone pattern from a value indicating a vertical position of a horizontal line to be drawn;
The halftone threshold value is read from the halftone threshold value storage means, gradation processing is performed using the read halftone threshold value, and the halftone pattern generated by the gradation processing is stored in the halftone pattern storage means Halftone pattern generation means for transferring to,
A half value for shifting the halftone pattern stored in the halftone pattern storage means using the remainder value is obtained by dividing the drawing width by the horizontal width of the halftone pattern. Halftone pattern shift value generating means for generating a tone pattern shift value;
The halftone pattern transferred from the halftone pattern storage means by the access by the halftone pattern address value is shifted by using the halftone pattern shift value generated by the halftone pattern shift value generating means. A cyclic shift means for performing a cyclic shift for a value;
Drawing means for drawing by repeatedly using a halftone pattern corresponding to drawing objects having the same gradation value by the cyclic shift;
An image processing apparatus, wherein the processing by the halftone pattern generation unit and the processing by the drawing unit are performed in parallel.   A drawing parameter storage means for storing drawing parameters used in the processing by the drawing means and the halftone pattern storage means are used as a double buffer, and a storage area for drawing processing and a storage area for the next drawing processing are provided. The image processing apparatus according to claim 1. An image processing method executed by an image processing apparatus that draws an image after gradation processing in units of bands indicating a predetermined range area,
Halftone threshold that stores the halftone threshold value of the halftone pattern of the drawing width, which is the width between the start and end points in the horizontal direction when the image is divided into drawing units, at least for the vertical width of the halftone pattern The halftone threshold value is read from the value storage means, gradation processing is performed using the read halftone threshold value, and the halftone pattern generated by the gradation processing is set to at least the halftone pattern of the drawing width. A halftone pattern generating step for transferring to the halftone pattern storage means for storing the vertical width of the halftone pattern;
Halftone pattern address generating means for generating a halftone pattern address value of the halftone pattern storage means storing the corresponding halftone pattern from a value indicating a vertical position of a horizontal line to be drawn;
A half value for shifting the halftone pattern stored in the halftone pattern storage means using the remainder value is obtained by dividing the drawing width by the horizontal width of the halftone pattern. A halftone pattern shift value generation step for generating a tone pattern shift value;
The halftone pattern transferred from the halftone pattern storage means by the access by the halftone pattern address value is shifted by using the halftone pattern shift value generated by the halftone pattern shift value generating step. A cyclic shift process for performing a cyclic shift for the value;
A drawing step of drawing by repeatedly using a halftone pattern corresponding to a drawing object having the same gradation value by the cyclic shift, and
An image processing method, wherein the processing by the halftone pattern generation step and the processing by the drawing step are performed in parallel.

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