JP2011053944A - Image forming device, image forming method, and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately parallelize image processing for execution of image formation output, thereby improving the processing efficiency of an image forming device having a plurality of computing means. <P>SOLUTION: The image forming device 1 capable of executing image processing using the plurality of computing means includes a DL processing unit 222 that generates a display list based on a page description language and stores the display list in an intermediate data storage unit 225, and a drawing process unit 226 that generates drawing information for drawing an object based on the display list stored. A DL generating unit 22 further includes a DL format conversion unit which checks the progress of a drawing process when the display list is stored in the intermediate data storage unit 225 and which converts the information format of the object of the display list when the progress is slow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, a control method, and a control program, and more particularly, to image processing when drawing information generation processing for executing image forming output can be executed by a plurality of arithmetic units.

  In recent years, there has been a tendency to digitize information, and image processing apparatuses such as printers and facsimiles used for outputting digitized information and scanners used for digitizing documents have become indispensable devices. Such an image processing apparatus is often configured as a multifunction machine that can be used as a printer, a facsimile, a scanner, or a copier by providing an imaging function, an image forming function, a communication function, and the like.

  Among such image processing apparatuses, a printer used for outputting digitized information performs image processing for generating drawing information for the print engine to execute image formation output based on the input image information. Is called. This image processing is executed by a calculation means such as a CPU (Central Processing Unit) operating according to software.

  Due to the recent development of information processing equipment, computing means such as a multi-core CPU including a plurality of computing means have become widespread. In a multi-core CPU, since a plurality of cores operate independently, the processing time can be shortened by parallelizing the processing. Accordingly, it is desired that the above-described image processing is also made more efficient by making it compatible with a multi-core CPU. In order to efficiently demonstrate the performance of the multi-core CPU, it is necessary to appropriately wait for one core during the operation of one core, that is, to prevent a wait from occurring, by appropriately allocating processing to each core. There is.

  As a method for utilizing a multi-core environment in an image forming apparatus, a method has been proposed in which the above-described image processing is divided into two stages and each of the two stages is executed by different CPUs (see, for example, Patent Document 1). ). In the technique disclosed in Patent Document 1, pipeline parallel execution is enabled by passing the processing result of the first core using a drawing object queue. In order to distribute the load between the two stages, it is determined at which stage the color conversion process is executed according to the number of standby drawing objects in the drawing object queue.

  Here, the above-described image processing is mainly divided into a PDL (Page Description Language) analysis process and a rendering process. The PDL analysis process is a process of analyzing PDL information configured in a page description language and converting it into a data format that can be processed by a module at a later stage. On the other hand, the rendering process is a process for generating drawing information for the print engine to execute image formation output based on the information converted by the PDL analysis.

  As a load distribution mode corresponding to the multi-core CPU, a mode in which the PDL analysis process and the rendering process are executed by different CPU cores can be considered. However, the amount of PDL analysis processing and rendering processing varies depending on the data, and efficient parallelization cannot always be realized depending on this aspect.

  In the case of the method disclosed in Patent Document 1, it is necessary to secure a memory area in order to provide a drawing object queue, and the amount of memory that can be used for processing is limited. Also, since it is intended only for color conversion processing, it is less effective for drawing monochrome pages with little color processing. Furthermore, there is data already waiting for processing at the time when the queue is generated, and parallel processing is not suitably performed.

  On the other hand, in the PDL analysis process, the processing amount of the drawing process is determined based on the amount of information included in the page, and a part of the drawing process is executed in the PDL analysis process according to the determination result. It is conceivable to make the balance between analysis processing and rendering processing uniform. However, when the above determination is performed for each page of the image formation output, the renderer side cannot start the process until the PDL analysis side finishes the process, and the renderer side may enter a standby state. Although it is possible to make adjustments for each page so that the renderer does not enter the standby state, the processing becomes complicated.

  Information is transferred from the PDL analysis process to the rendering process for each page of the image formation output. Even if the balance between the PDL analysis process and the rendering process is made uniform, the PDL analysis is performed for the first page. The renderer side is in a standby state until the processing is completed. For the last page, after the PDL analysis process is completed and the renderer side starts processing, the PDL analysis side is in a standby state. That is, the period during which any one of the plurality of cores is in a standby state is long, and parallel processing is not suitably performed.

  The present invention has been made in consideration of the above circumstances, and in an image forming apparatus having a plurality of calculation means, appropriately parallelizes image processing for executing image forming output, and improves processing efficiency. Objective.

  In order to solve the above problems, one aspect of the present invention is an image forming apparatus capable of executing image processing for executing image forming output by a plurality of arithmetic units, and obtained based on a page description language A drawing command acquisition unit that acquires a drawing command, a graphic information acquisition unit that acquires graphic information describing a graphic included in an image to be output based on the drawing command, and stores the acquired graphic information in a storage medium A graphic information storage processing unit for generating, a drawing processing unit for generating drawing information for drawing the graphic based on the stored graphic information, and the drawing information when the graphic information is stored in the storage medium A drawing processing progress confirmation unit for confirming the progress of the drawing processing for generating information, and when the progress is confirmed to be low, the information processing format of the graphic information is converted and executed in the drawing processing unit. Characterized in that it comprises an information conversion unit to reduce the physical quantity.

  Here, it is preferable that the graphic information acquisition unit, the drawing processing progress confirmation unit, the graphic information storage processing unit, the information conversion unit, and the drawing processing unit are realized by different calculation means.

  In addition, the image processing apparatus further includes a processing amount calculation unit that calculates a processing amount of processing for generating the drawing information based on the graphic information stored in the storage medium, and the drawing processing progress confirmation unit includes the calculated processing amount. It is preferable to check the progress of the drawing process based on the above.

  Further, it is preferable that the drawing process progress confirmation unit calculates a remaining amount of the drawing process based on the calculated processing amount, and confirms the progress of the drawing process based on the calculated remaining amount.

  In addition, the drawing process progress confirmation unit can confirm that the progress is low when the calculated remaining amount is greater than a predetermined threshold.

  Further, it is preferable that the processing amount calculation unit calculates the processing amount of the drawing processing according to the calculation capability of the plurality of calculation means.

  In addition, the processing amount calculation unit calculates the processing amount based on a variable element that varies depending on the content of the drawing command and a fixed element that is determined by the performance of hardware that constitutes the image forming apparatus. Is preferred.

  Further, the processing amount calculation unit calculates the variation element so that the contribution rate to the entire variation element differs for each of the plurality of types of processing included in the drawing command according to the contents of the plurality of types of processing. It is preferable to do.

  Moreover, it is preferable that the drawing process progress confirmation unit confirms the progress of the drawing process based on the graphic information stored in the storage medium.

  The information conversion unit can execute part or all of scan line conversion when the information format of the graphic information is vector data.

  Further, the information conversion unit can execute part or all of color matching, CMYK conversion, and total amount regulation when the information format of the graphic information is image data.

  On the other hand, according to another aspect of the present invention, there is provided an image forming method in which image processing for executing image forming output is executed by a plurality of calculation means, wherein the drawing command acquisition unit is obtained based on a page description language A drawing command is acquired, a graphic information acquisition unit acquires graphic information describing a graphic included in the image to be output based on the drawing command, and a graphic information storage processing unit stores the acquired graphic information. The drawing processing unit generates drawing information for drawing the graphic based on the stored graphic information, and the drawing processing progress confirmation unit stores the graphic information in the storage medium. In this case, the progress of the drawing process for generating the drawing information is confirmed, and when the information conversion unit confirms that the progress is low, the information processing unit converts the information format of the graphic information and executes it in the drawing processing unit. Processing amount Characterized in that it reduced.

  According to another aspect of the present invention, there is provided a control program for controlling an image forming apparatus capable of executing image processing for executing image formation output by a plurality of arithmetic means, and obtained based on a page description language. Acquiring a drawing command; acquiring graphic information describing a graphic included in an image to be output based on the drawing command; storing the acquired graphic information in a storage medium; A step of generating drawing information for drawing the graphic based on the generated graphic information, and a step of confirming a progress of a drawing process for generating the drawing information when the graphic information is stored in the storage medium And, when it is confirmed that the progress is low, converting the information format of the graphic information to reduce the processing amount executed in the drawing processing unit. Characterized in that to be executed by the serial image forming apparatus.

  According to the present invention, in an image forming apparatus having a plurality of computing units, it is possible to appropriately parallelize image processing for executing image forming output and improve processing efficiency.

1 is a block diagram illustrating a hardware configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a diagram illustrating a functional configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the function contained in the image process part which concerns on embodiment of this invention. It is a figure which shows the information format of the printing information which concerns on embodiment of this invention, and the process performed according to the information format. It is a figure which shows an example. It is a figure which shows the function contained in the drawing core module which concerns on embodiment of this invention. It is a figure which shows the example of the image of the process target which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the PDL application which concerns on embodiment of this invention. It is a figure which compares and shows the parallel processing which concerns on embodiment of this invention, and the parallel processing which concerns on a prior art. It is a figure which shows the scan line conversion process which concerns on embodiment of this invention. It is a figure which shows the image drawing process which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present exemplary embodiment, an image forming apparatus as an MFP (Multi Function Peripheral) including functions of a printer, a scanner, a copier, and the like will be described as an example.

  FIG. 1 is a block diagram illustrating a hardware configuration of an image forming apparatus 1 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes an engine that executes image formation in addition to the same configuration as an information processing terminal such as a general server or a PC (Personal Computer). That is, the image forming apparatus 1 according to the present embodiment includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, an engine 40, a HDD (Hard Disk Drive) 50, and an I / O. F60 is connected via the bus 90. Further, an LCD (Liquid Crystal Display) 70 and an operation unit 80 are connected to the I / F 60.

  The CPU 10 is a calculation unit and controls the operation of the entire image forming apparatus 1. The CPU 10 according to the present embodiment is a quad-core CPU, and includes a first core 11, a second core 12, a third core 13, and a fourth core 14. Since the first core 11, the second core 12, the third core 13, and the fourth core 14 operate independently, parallel processing can be performed, and processing time can be shortened. The RAM 20 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 10 processes information. The ROM 30 is a read-only nonvolatile storage medium and stores a program such as firmware. The engine 40 is a mechanism that actually executes image formation in the image forming apparatus 1.

  The HDD 50 is a non-volatile storage medium that can read and write information, and stores an OS (Operating System), various control programs, application programs, and the like. The I / F 60 connects and controls the bus 90 and various hardware and networks. The LCD 70 is a visual user interface for the user to check the state of the image forming apparatus 1. The operation unit 80 is a user interface for a user to input information to the image forming apparatus 1 such as a keyboard and a mouse.

  In such a hardware configuration, a program stored in a recording medium such as the ROM 30 or the HDD 50 or an optical disk (not shown) is read out to the RAM 20 and operates according to the control of the CPU 10 to constitute a software control unit. A functional block that realizes the functions of the image forming apparatus 1 according to the present embodiment is configured by a combination of the software control unit configured as described above and hardware.

  Next, the functional configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating a functional configuration of the image forming apparatus 1 according to the present embodiment. As shown in FIG. 2, the image forming apparatus 1 according to the present embodiment includes a controller 100, an ADF (Auto Document Feeder) 110, a scanner unit 120, a paper discharge tray 130, a display panel 140, and a paper feed table. 150, a print engine 160, a paper discharge tray 170, and a network I / F 180.

  The controller 100 includes a main control unit 101, an engine control unit 102, an input / output control unit 103, an image processing unit 104, and an operation display control unit 105. As shown in FIG. 2, the image forming apparatus 1 according to the present embodiment is configured as a multifunction machine having a scanner unit 120 and a print engine 160. In FIG. 2, the electrical connection is indicated by solid arrows, and the flow of paper is indicated by broken arrows.

  The display panel 140 is an output interface that visually displays the state of the image forming apparatus 1 and is an input when the user directly operates the image forming apparatus 1 or inputs information to the image forming apparatus 1 as a touch panel. It is also an interface (operation unit). The network I / F 180 is an interface for the image forming apparatus 1 to communicate with other devices via the network, and uses an Ethernet (registered trademark) or a USB (Universal Serial Bus) interface.

  The controller 100 is configured by a combination of software and hardware. Specifically, a control program such as firmware stored in a ROM 30, a nonvolatile memory, and a nonvolatile recording medium such as the HDD 50 or an optical disk is loaded into a volatile memory (hereinafter referred to as a memory) such as the RAM 20, and is controlled by the CPU 10. The controller 100 is configured by a software control unit configured according to the above and hardware such as an integrated circuit. The controller 100 functions as a control unit that controls the entire image forming apparatus 1.

  The main control unit 101 plays a role of controlling each unit included in the controller 100, and gives a command to each unit of the controller 100. The engine control unit 102 serves as a drive unit that controls or drives the print engine 160, the scanner unit 120, and the like. The input / output control unit 103 inputs a signal or a command input via the network I / F 180 to the main control unit 101. The main control unit 101 also controls the input / output control unit 103 to access other devices via the network I / F 180.

  The image processing unit 104 generates drawing information based on the print information included in the input print job, under the control of the main control unit 101. The drawing information is information for drawing an image to be formed in the image forming operation by the print engine 160 as an image forming unit. Also, the print information included in the print job is information converted into a format that can be recognized by the image forming apparatus 1 by a printer driver installed in an information processing apparatus such as a PC, and is described by PDL (Page Description Language). Information. In other words, the print information is an execution command for causing the image forming apparatus 1 to start image formation output. In this embodiment, the case where PDL is used as the page description language is taken as an example, but another language may be used.

  In the present embodiment, the above-described drawing information generation processing by the image processing unit 104 is suitably allocated to the first core 11, the second core 12, the third core 13, and the fourth core 14 of the multi-core CPU 10. Become. The function of the image processing unit 104 will be described in detail later. The operation display control unit 105 displays information on the display panel 140 or notifies the main control unit 101 of information input via the display panel 140.

  When the image forming apparatus 1 operates as a printer, first, the input / output control unit 103 receives a print job via the network I / F 180. The input / output control unit 103 transfers the received print job to the main control unit 101. When receiving the print job, the main control unit 101 controls the image processing unit 104 to generate drawing information based on the print information included in the print job.

  When drawing information is generated by the image processing unit 104, the engine control unit 102 executes image formation on a sheet conveyed from the paper feed table 150 based on the generated drawing information. That is, the print engine 160 functions as an image forming unit. As a specific mode of the print engine 160, an image forming mechanism using an ink jet method, an image forming mechanism using an electrophotographic method, or the like can be used. The document on which the image has been formed by the print engine 160 is discharged to the discharge tray 170.

  When the image forming apparatus 1 operates as a scanner, the operation display control is performed according to a user operation on the display panel 140 or a scan execution instruction input from an information processing terminal for an external client via the network I / F 180. The unit 105 or the input / output control unit 103 transfers a scan execution signal to the main control unit 101. The main control unit 101 controls the engine control unit 102 based on the received scan execution signal.

  The engine control unit 102 drives the ADF 110 and conveys the document to be imaged set on the ADF 110 to the scanner unit 120. Further, the engine control unit 102 drives the scanner unit 120 and images a document conveyed from the ADF 110. If no original is set on the ADF 110 and the original is set directly on the scanner unit 120, the scanner unit 120 images the set original according to the control of the engine control unit 102. That is, the scanner unit 120 operates as an imaging unit.

  In the imaging operation, an imaging element such as a CCD included in the scanner unit 120 optically scans the document, and imaging information generated based on the optical information is generated. The engine control unit 102 transfers the imaging information generated by the scanner unit 120 to the image processing unit 104. The image processing unit 104 generates image information based on the imaging information received from the engine control unit 102 according to the control of the main control unit 101. Image information generated by the image processing unit 104 is stored in a storage medium attached to the image forming apparatus 1 such as the HDD 40. That is, the scanner unit 120, the engine control unit 102, and the image processing unit 104 work together to function as a document reading unit.

  The image information generated by the image processing unit 1104 is stored as it is in the HDD 40 or the like according to a user instruction, or is transmitted to an external device via the input / output control unit 103 and the network I / F 180. That is, the scanner unit 120 and the engine control unit 102 function as an image input unit.

  Further, when the image forming apparatus 1 operates as a copying machine, the image processing unit 104 generates drawing information based on imaging information received by the engine control unit 102 from the scanner unit 120 or image information generated by the image processing unit 104. To do. Based on the drawing information, the engine control unit 102 drives the print engine 160 as in the case of the printer operation.

  In such an image forming apparatus 1, the gist of the present embodiment lies in the division and parallel processing of processing when the image processing unit 104 generates drawing information. Hereinafter, functions and operations of the image processing unit 104 according to the present embodiment will be described. FIG. 3 is a block diagram illustrating functions included in the image processing unit 104 according to the present embodiment. As illustrated in FIG. 3, the image processing unit 104 according to the present embodiment includes a PDL application 200 configured by a PDL analysis unit 210 and a drawing core module 220.

  The PDL analysis unit 210 acquires print information described in PDL and converts it into a format that can be processed by the drawing core module 220. The converted format information is processed as a rendering command in the PDL application 200. That is, the PDL analysis unit 210 functions as a page information acquisition unit and a page information analysis unit. Here, FIG. 4 shows the information format of the information included in the print information described in PDL and the processing executed in accordance with each information format.

  As shown in FIG. 4, in the case of vector data, an image is converted into a bitmap through a scan line conversion process. In the case of text data, the image is converted into a bitmap through the outline of the text and the scan line conversion of the outline. In the case of compressed image data, processing as image data is performed through decompression processing corresponding to the compression format. In the case of moving image data, processing as image data is performed through extraction processing of frames constituting the moving image. When a moving image is compressed, an image expansion process is performed in the same manner as the compressed still image data. For image data, color matching, CMYK (Cyan, Magenta, Yellow, Key) conversion and total amount restriction processing are executed.

  The drawing core module 220 generates drawing information for the print engine 160 to execute image formation output based on the drawing command converted by the PDL analysis unit 210. Among the functions of the image processing unit 104 illustrated in FIG. 3, the PDL analysis unit 210 is processed only by the first core 11. On the other hand, the drawing core module 220 is distributed by the first core 11, the second core 12, the third core 13, and the fourth core 14. That is, the function of the drawing core module 220 is one of the gist according to the present embodiment.

  The function of the drawing core module 220 will be described with reference to FIG. FIG. 5 is a block diagram illustrating functions included in the drawing core module 220. As shown in FIG. 5, the drawing core module 220 according to the present embodiment includes a drawing core module I / F 221, a DL (Display List) processing unit 222, a load index calculation unit 223, a DL format conversion unit 224, an intermediate A data storage unit 225 and a plurality of drawing processing units 226 are included. Among the components included in FIG. 4, the drawing core module I / F 221, the DL processing unit 222, the load index calculation unit 223, and the DL format conversion unit 224 are controlled by the first core 11, and a plurality of drawing processing units 226 are configured. It is controlled by any one of the second core 12, the third core 13, and the fourth core 14. Each functional block controlled by the first core 11, the second core 12, the third core 13, and the fourth core 14 is a module constituting a drawing core module 220 realized as a software program.

  The drawing core module I / F 221 acquires the drawing command converted by the PDL analysis unit 210. That is, the drawing core module I / F 221 functions as a drawing command acquisition unit. The DL processing unit 222 generates a display list based on the drawing command acquired by the drawing core module I / F 221 and stores the display list in the intermediate data storage unit 225. The display list is graphic information describing a graphic included in an image to be imaged and output. That is, the DL processing unit 222 functions as a graphic information acquisition unit and a graphic information storage processing unit, and the intermediate data storage unit 225 functions as a graphic information storage unit.

  Also, the DL processing unit 222 transfers the drawing command information acquired by the drawing core module I / F 221 to the load index calculation unit 223 for each graphic information described above, and the load index calculation unit 223 performs load index calculation processing. Is executed. Further, the DL processing unit 222 determines the processing state of the drawing processing in the plurality of drawing processing units 226 based on the calculation result of the load index by the load index calculating unit 223, and based on the determination result, the DL processing unit 224 The information format of the graphic information is converted. That is, the DL processing unit 222 functions as a drawing process progress confirmation unit, and the DL format conversion unit 224 functions as an information conversion unit in conjunction with each other.

  The load index calculation unit 223 calculates a load index for generating drawing information for the input graphic based on the information input from the DL processing unit 222, that is, the print information converted from the PDL format. The load index is a numerical value indicating the processing amount for the drawing information generation processing, and is a numerical value in which the processing capacity of hardware such as the CPU 10 and the RAM 20 is added to the amount of information to be processed, that is, the processing amount. That is, the load index calculation unit 223 functions as a processing amount calculation unit. The calculation mode of the load index according to this embodiment will be described below.

  In the present embodiment, as an example of parameters for calculating the load index of the drawing information generation process, the number of Bezier curve control points in the vector data, the data size of the image data, the size of the drawing area, and the performance of the drawing processing means are used. . In a Bezier curve, line segments (paths) are generated by dividing between control points. Therefore, the larger the number of control points, the more division processing occurs. Therefore, the processing amount is proportional to the number of control points of the Bezier curve. Further, the processing amount of text data and vector data varies depending on the drawing area.

  In the case of image drawing, input data is expressed by RGB (Red Green Blue) 24-bit or Index data, and each pixel of the data is subjected to processing such as color matching processing and rotation processing. That is, the larger the data size, the more processing described above occurs. Therefore, the processing amount is proportional to the data size of the input image.

  Even if the image size of the input data is small, if the area to be drawn using the image is large, the cost required for calculation and memory access increase. This is because it is necessary to perform calculation and writing for each drawing destination pixel. Therefore, the processing amount is proportional to the size of the drawing area.

  In addition, when using a homogeneous multi-core CPU, the performance is the same as each other, but in the case of a heterogeneous multi-core CPU, the performance differs depending on the core, so the weight differs depending on which core is used for processing. . The same applies when a core or hardware accelerator specialized for scanline conversion is used. Here, the scan line conversion is a process of converting the above-described Bezier curve in the vector data into raster data, that is, a bitmap.

Based on these parameters, the load index calculation unit 223 calculates the load index W using the following equation (1). In equation (1), “B” is the number of control points of the Bezier curve, “D” is the input data size, “S” is the size of the drawing area, and these are the fluctuation factors of the load index W. . “P” is the performance of the drawing processing means, which is a fixed factor of the load index W. “P” according to this embodiment is a coefficient corresponding to the performance of each of the first core 11, the second core 12, the third core 13, and the fourth core, and may be a negative value. “A” to “b” are respective weighting factors. Depending on the weighting factor, the contribution rate to the value of the load index W differs for each item such as “B”, “D”, and “S”.

  The load index calculation unit 223 stores the load index calculated as described above. The load index stored in the load index calculation unit 223 is referred to by the DL processing unit 222 and is used as a material for determining whether or not the information format conversion by the DL conversion unit 224 is necessary as described above. This will be described in detail later.

  Information format conversion processing by the DL format conversion unit 224 includes vector data scan line conversion processing, image data color matching processing and rotation processing, text data outline conversion and scan line conversion, and the processing described in FIG. That is, part of the drawing information generation process is included.

  The intermediate data storage unit 225 is a storage medium for transferring data being processed from the module controlled by the first core 11 to the module controlled by the second core 12. In the present embodiment, as described above, the DL format conversion unit 224 performs part of the drawing information generation process in accordance with the determination of the processing status of the drawing writing unit 226 based on the load index by the DL processing unit 222. Executed. Therefore, in the intermediate data storage unit 225, information converted from the PDL format by the intermediate data processing unit 222 and configured as a display list is stored, and information converted by the DL format conversion unit 224 is stored.

  The plurality of drawing processing units 226 generates drawing information for inputting drawing data to the engine control unit 102 based on the information stored in the intermediate data storage unit 225. The processing modes by the plurality of drawing processing units 226 include processing for generating drawing information from information analyzed by the PDL analysis unit 210 and configured as a display list by the DL processing unit 222, and scanning lines by the DL format conversion unit 224. This includes processing for generating drawing information from information in the middle of processing that has undergone processing such as conversion and color matching. The plurality of drawing processing units 226 outputs the generated drawing information to the page memory.

  As described above, the plurality of drawing processing units 226 are controlled by any one of the second core 12, the third core 13, and the fourth core 14, respectively. That is, the drawing processing unit 226 can operate in parallel during a period in which the first core 11 stores the intermediate data in the intermediate data storage unit 225 and executes the PDL analysis process for the next page. Thereby, a process can be distributed to the 1st core 11 and the 2nd core 12-the 4th core 14, and processing time can be shortened by parallel processing.

  Next, the operation of the PDL application 200 according to the present embodiment will be described with reference to the drawings. In the present embodiment, an image as shown in FIG. 6 will be described as an example of an image to be imaged and output (hereinafter referred to as an output image). As shown in FIG. 6, the output image according to the present embodiment includes three graphics of an image A, a text B, and a vector C as objects constituting the image. Also, as shown in FIG. 6, the PDL application 200 according to the present embodiment divides one page into three areas of “band 0”, “band 1”, and “band 2”, and each area is divided. Generate drawing information. Further, in the PDL application 200 according to the present embodiment, the second core 12 to the fourth core 14 that respectively control the plurality of drawing processing units 226 generate the drawing information of each band, thereby parallelizing the processing.

  FIG. 7 is a flowchart showing the operation of the PDL application 200 according to this embodiment. FIG. 8 is a diagram schematically illustrating a parallel operation of a display list generation process (Pers) and a rendering process (Render) in the PDL application 200 according to the present embodiment, and a conventional parallel operation. FIG. 8 shows an example in which print information for three pages is input.

  When the image processing unit 104 acquires print information in the PDL format, the PDL application 200 starts operating. First, the first core 11 controls the PDL analysis unit 210, analyzes the input PDL data, and converts it into a data format that can be processed by the drawing core module 220 (S701). Information converted by the PDL analysis unit 210 (hereinafter referred to as a drawing command) is input to the DL processing unit 222 via the drawing module I / F 221.

  Next, the DL processing unit 222 selects one object included in the image to be output in the drawing command acquired from the drawing core module I / F 221 (S702). This figure is one of the image A, the text B, and the vector C shown in FIG. Here, it is assumed that the image A is selected. Then, the DL processing unit 222 inputs the object selected in S702 to the load index calculation unit 223. Accordingly, the first core 11 controls the load index calculation unit 223, and the load index calculation unit 223 executes a load index calculation process (S703). The process of S703 according to the present embodiment is executed according to the above-described equation (1). When the load index is calculated by the process of S703, the load index calculation unit 223 stores the calculated load index.

  Next, the DL processing unit 222 refers to the load index calculated and stored by the load index calculation unit 223 in the previous cycle (hereinafter referred to as the previous cycle load index), and determines the processing status of the drawing process in the drawing processing unit 226. Confirmation (S704), and load distribution processing is executed based on the result (S705).

  Here, since the process for the first object is the first cycle, there is no previous cycle load index, and the drawing processing unit 226 has not yet started the drawing process. In this case, the DL processing unit 222 determines that the drawing processing unit 226 is in a standby state and that there is a sufficient margin in processing capacity. In this case, in step S <b> 705, the DL processing unit 222 determines not to assign a process to the DL format conversion unit 224 and to execute a drawing process in each of the plurality of drawing processing units 226. That is, depending on the processing result of S705, the information format conversion processing (S706) by the DL format conversion unit 224 is an empty processing in which no processing is actually executed.

When the processing up to S706 is completed, the DL processing unit 222 causes the intermediate data storage unit 225 to store information on the rendering command configured as a display list for the object selected in S702 (S707). Timing of the processing of S707 of the first cycle, a timing of t ₁ shown in FIG. When the processing of S707 is completed, the drawing processing unit 226 controlled by any of the second core 12 to the fourth core 14 executes drawing processing for generating drawing information (S710).

  As described above, since the image A is selected in S702 described above and the image A exists in the band 0 and the band 1, as shown in FIG. 8, first, the second corresponding to the band 0 and the band 1 is displayed. The drawing processing units 226 of the core 12 and the third core 13 start drawing processing. On the other hand, in the first core 11, when the process of S707 is completed, it is determined whether or not the process has been completed for all objects included in the drawing command acquired by the process of S701 (S708). Since the processing is not completed here (S708 / NO), the processing from S702 is repeated.

  Next, description will be made assuming that the vector C is selected in the second cycle returning to S702 (S702). When the vector C is selected as the target object, the load index calculation process for the vector C is executed in the same manner as described above (S703), and the load index is stored. In the same manner as described above, the processing status of the rendering processing unit 226 as a renderer is confirmed (S704).

  Here, since the load index of the image A is stored as the previous cycle load index, the processing status of the drawing processing unit 226 is determined based on the information. In this processing status determination process, for example, the previous cycle load index is subtracted based on the elapsed time since the intermediate data is stored in the intermediate data storage unit 225 in S707 of the previous cycle, and the remaining load index is calculated. Thus, the processing amount in the standby state among the processing to be processed by the drawing processing unit 226 (hereinafter referred to as standby processing amount) is calculated.

  When the processing status of the renderer is calculated, the DL processing unit 222 executes load distribution processing (S705). Here, the allocation of processing to the DL format conversion 224 is determined based on the standby processing amount calculated in S704. For example, the load index calculated in S703 of the current cycle (hereinafter referred to as the current cycle load index) is compared with the calculated standby processing amount, and the current cycle load index may be significantly smaller than the standby processing amount. For example, no process is assigned to the DL format conversion unit 224. As a high-order judgment criterion, for example, the current cycle load index is 50% or less, 30% or less, and further 10% or less of the standby processing amount.

  As another determination method in S705, there is a method in which a threshold is provided for the calculated standby processing amount, and a process is assigned to the DL format conversion unit 224 if the calculated standby processing amount is larger than the threshold. In addition, the threshold value is provided in stages, and more processing is allocated to the DL format conversion unit 224 as the standby processing amount is higher than the threshold value provided in stages, that is, exceeds a threshold value with a larger value. it can.

When the processing of S705 is completed, the DL format conversion unit 224 executes the processing for the amount allocated by the processing of S705. Then, the DL processing unit 222 stores the intermediate data in the intermediate data storage unit 225 (S707). In this way, the intermediate data is stored in the intermediate data storage unit 225 for the vector C. because present in 2, as shown in the timing t ₂ in FIG. 8, a fourth core 14 corresponds to the band 2 starts processing. Although the vector C is also present in the band 1, since the third core 13 corresponding to the band 1 has already undergone the processing, the processing of the vector C is completed as soon as the processing currently being executed is completed. Start drawing process.

When the processing of S707 is completed in this way, the DL processing unit 222 determines again whether the processing for the previous object is completed, and repeats the processing from S702 until the processing for the previous object is completed (S708 / NO). ). When the process for the previous object is completed (S708 / YES), the PDL application 200 next determines whether all the pages included in the input PDL data have been processed (S709). If not (S709 / NO), the processing from S701 is repeated to execute the processing after PDL analysis for other pages. Timing becomes "NO" at S709 is, the timing _{t 3} and _{t 4} shown in FIG. 8, i.e., a switching timing of the processing page. Then, when the processing is completed for all pages (S709 / YES), the processing ends as it is.

  On the other hand, in the second core 12 to the fourth core 14, each drawing processing unit 226 executes drawing information generation processing based on the intermediate data stored in the intermediate data storage unit 225 by the DL processing unit 222 ( S710). When the drawing process for one object is completed, the drawing processing unit 226 determines whether the drawing process for all objects included in one page is completed (S711), and if not completed (S711). / NO), the process of S710 is repeated.

  If the drawing processing for all objects included in one page is completed (S711 / YES), the drawing processing unit 226 outputs the drawing information to the page memory (S712), and the processing is completed for all pages. It is determined whether or not (S713). If drawing processing has not been completed for all pages (S713 / NO), the drawing processing unit 226 repeats the processing from S710, and when drawing processing has been completed for all pages (S713 / YES), the processing ends. To do. By such processing, the operation of the PDL application 200 according to the present embodiment is completed.

As a result of such processing, as in the period T ₁ and T ₂ of the prior art shown in FIG. 7, the parallel processing so that the waiting time will not occur in the drawing processing unit 226 is performed efficiently, the period in FIG. 8 T as shown as _3, can be a time until the drawing processing of the third page is completed is shorter than the prior art.

In the prior art, since the processing is divided in units of pages, the timing at which the drawing processing unit 226 starts the drawing processing for the first page is the timing at which the display list for the first page is completely generated, that is, It was timing _{t 3} when shown in FIG. 8. On the other hand, since the PDL application 200 according to the present embodiment divides the display list generation processing and drawing processing into parallel objects, the first first of the objects included in the first page is included. timing display list of objects is created, namely from the timing t ₁ shown in FIG. 8, may be drawing processing unit 226 starts the rendering process. Thereby, parallelization of processing is further promoted, and processing efficiency can be improved.

  In the PDL application according to the present embodiment, when the DL processing unit 222 generates a display list and stores the display list in the intermediate data storage unit 225, the processing statuses of a plurality of drawing processing units 226 operating as renderers are checked. If there are many display lists waiting for processing by the rendering processing unit 226, that is, display lists remaining in an unprocessed state in the intermediate data storage unit 225, load distribution is executed and information is sent to the DL format conversion unit 224. By executing the format conversion, the load on the drawing processing unit 226 is reduced.

  This prevents the processing speed of the drawing processing unit 226 from catching up with the speed at which the DL processing unit 222 generates the display list and stores it in the intermediate data storage unit 225, and prevents the waiting time from occurring on the DL processing unit 222 side. Can do.

  As described above, in the image forming apparatus 1 according to the present embodiment, in the image forming apparatus having a plurality of arithmetic units, the image processing for executing the image forming output is appropriately parallelized to improve the processing efficiency. It becomes possible.

  In the above embodiment, as shown in FIG. 1, the case where a quad-core CPU 10 is used has been described as an example. However, the present invention is not particularly limited to this. You may apply to CPU which has.

  In the above embodiment, as shown in FIG. 5, the intermediate data processing unit 222 that generates the drawing information by the control of the first core 11 and the drawing information by the control of the second core 12 to the fourth core 14. The drawing processing unit 226 that performs generation is shown as a separate block. However, in the drawing information generation process, the process in the middle of scan line conversion and color matching is the same process regardless of which of the first core 11 to the fourth core 14 is executed, and the intermediate data processing unit The software program for realizing 222 and the drawing processing unit 226 can be the same. Furthermore, the module included in the software program includes only a single module. Depending on which one of the first core 11 and the second core 12 controls, the intermediate data processing unit 222 or the drawing processing unit 226 is used. It can also be configured to function as. Even in this case, since the functions are realized in parallel by being controlled by the first core 11 and the second core 12, the first drawing information generating unit and the second drawing information generating unit 1 are provided inside the image forming apparatus 1. A drawing information generation unit is configured.

  In the above embodiment, the DL processing unit 222 calculates the standby processing amount of the drawing processing unit 226 by referring to the previous cycle load index stored in the load index calculation unit 223 in S704 of FIG. In the above example, the load distribution mode is determined based on the standby processing amount. In addition, the DL processing unit 222 may refer to the amount of information remaining in the intermediate data storage unit 225 as unprocessed. This also makes it possible to determine the standby processing amount and obtain the same effect as described above.

  The method for referring to the amount of information remaining as unprocessed in the intermediate data storage unit 225 differs depending on the processing specifications of the drawing processing unit 226. For example, if the specification is such that the data of an object for which processing has been completed is immediately deleted from the intermediate data storage unit 225, the DL processing unit 222 sets the capacity of the object data stored in the intermediate data storage unit 225. Based on this, the standby processing amount can be determined. On the other hand, when there is a time difference between the completion of processing and deletion from the intermediate data storage unit 225, the above method cannot accurately determine the standby processing amount. In this case, each time the drawing processing unit 226 executes the drawing processing for each object, the DL processing unit 222 refers to the flag to perform standby processing by writing a flag indicating the executed processing in the intermediate data storage unit. The amount can be judged.

  In the example of FIG. 8, an ideal case where the processing times of the second core 12 to the fourth core 14 are equal is described as an example, but the processing time of the second core 12 to the fourth core 14 is described. There may be a slight difference between the two. This is because each core is assigned to each band, and the objects included in each band are different. In this case, when the DL processing unit 222 determines the processing status of the drawing processing unit 226, the core with the least progress, the core with the most progress among the second core 12 to the fourth core 14, or each core It is possible to determine the standby processing amount by referring to the average progress.

  In the drawing core module 220 according to the present embodiment, each drawing processing unit 226 can share data stored in the intermediate data storage unit 225. This makes it possible to divide the drawing process for the same object by a plurality of cores. For example, as described above, when the fourth core 14 starts drawing processing for the vector C first, the third core 13 uses the data about the vector C processed by the fourth core 14 to use the vector C. The drawing information of the part included in band 1 can be generated. As a result, as described above, since the objects included in each band are different, it is possible to reduce the difference that occurs in the processing time of each core. Such an example will be described with reference to FIGS. 9A to 9E and FIGS. 10A to 10D.

  FIGS. 9A to 9E are diagrams showing each stage of the scan line conversion process of the vector C shown in FIG. 6 as an example of the drawing process by the drawing processing unit 226. FIG. A Bezier curve of vector data is composed of coordinate data of end points and control points. FIG. 9A is a plot example in the case of having end points P0 and P3 and control points P1 and P2 as points constituting a Bezier curve.

  FIG. 9B is a diagram in which curved paths are drawn for the end points and control points as shown in FIG. The method of drawing a curved path from the end points and control points is a well-known method and will not be described in detail. However, a line segment connecting two adjacent points is divided at an arbitrary ratio to draw a point. One point on the path is obtained by obtaining a point that further divides the connecting line segment at the same rate. A point indicating a curved path is drawn by repeating the same processing while changing the arbitrary ratio. As shown in FIG. 9B, the process of drawing a curved path is a path creation process that is the first stage of scanline conversion.

  When the path creation process is completed, a conversion process from a vector data path to a bit path is executed as shown in FIG. The process shown in FIG. 9C is a bit path conversion process which is the second stage of the scan line conversion.

  When the bit pass conversion process is completed, next, as shown in FIG. 9D, a process of filling pixels surrounded by the pass is executed. Here, the necessity of painting is determined based on the FILL setting of the original vector data, and if it is set to perform painting, an image in which the inside of the path is painted as shown in FIG. 9D is generated. The The process shown in FIG. 9D is a FILL process that is the third stage of the scan line conversion.

  When the FILL process is completed, an image clipping process is executed based on the set clip, as shown in FIG. As described above, the clip information of each band is included in the band management data. Accordingly, in each drawing process, each drawing unit refers to the clip information included in the band management data, and cuts out an object as shown in FIG.

  In the case of the above-described embodiment, the drawing processing unit 226 controlled by the fourth core 14 corresponding to the band 2 first executes the drawing process of the vector C. Therefore, the drawing processing unit 226 controlled by the fourth core 14 executes the processes of FIGS. 9A to 9E, and cuts out the portion corresponding to the band 2 in the process of FIG. The drawing processing unit 226 controlled by the fourth core 14 stores the information processed up to the stage of FIG. 9D in the intermediate data storage unit 225 as a drawing cache.

  Accordingly, when the drawing processing unit 226 controlled by the third core 13 corresponding to the band 1 executes the drawing process of the vector C, the drawing cache stored in the intermediate data storage unit 225 is used, thereby FIG. The drawing process of the vector C can be completed by omitting the processes from (a) to (d) and executing only the clipping process of FIG. When the third core 13 executes the cutout process of FIG. 9E as the drawing process of the vector C, the part corresponding to the band 1 is cut out.

  FIGS. 10A to 10D are diagrams illustrating each stage of the drawing process of the image A illustrated in FIG. 6 as an example of the drawing process performed by the drawing processing unit 226. The image data is generally configured as RGB format data as shown in FIG. FIG. 10B is a diagram illustrating a state in which color matching processing is performed on the RGB format data illustrated in FIG.

  When the color matching processing is completed, next, conversion processing from the RGB format to the CMYK format is executed as shown in FIG. The RGB format image data is converted into CMYK color data by the conversion process to CMYK. When the CMYK conversion process is completed, next, as shown in FIG. 9D, the total amount restriction process for each CMYK value is executed. This completes the image data drawing process.

  When distributing such image data processing, for example, the second core 12 can be assigned color matching processing, the third core 13 can be CMYK conversion processing, and the fourth core 14 can be assigned total amount restriction processing. In addition, unlike vector data, RGB data is data that can be divided into portions, so that each core may perform color matching, CMYK conversion, and total amount restriction processing for each portion.

1 image forming apparatus,
10 CPU,
11 First core,
12 Second core,
20 RAM,
30 ROM,
40 engines,
50 HDD,
60 I / F,
70 LCD,
80 operation unit,
90 bus,
100 controller,
111 main control unit,
112 engine control unit,
113 Input / output control unit,
114 image processing unit,
115 operation display control unit,
110 ADF,
120 scanner unit,
130 paper output tray,
140 display panel,
150 paper feed table,
160 print engine,
170 paper output tray,
180 Network I / F,
200 PDL applications,
210 PDL analysis unit,
220 drawing core module,
221 Drawing core module I / F,
222 DL processing unit,
223 load index calculation unit,
224 DL format converter,
225 intermediate data storage unit,
226 drawing processing unit,

JP 2007-73005 A

Claims (13)

An image forming apparatus capable of executing image processing for executing image formation output by a plurality of arithmetic means,
A drawing command acquisition unit for acquiring a drawing command obtained based on the page description language;
A graphic information acquisition unit that acquires graphic information describing a graphic included in an image to be output based on the drawing command;
A graphic information storage processing unit for storing the acquired graphic information in a storage medium;
A drawing processing unit for generating drawing information for drawing the figure based on the stored figure information;
When the graphic information is stored in the storage medium, a drawing processing progress confirmation unit for confirming the progress of the drawing processing for generating the drawing information;
An image forming apparatus comprising: an information conversion unit that converts an information format of the graphic information to reduce a processing amount executed in the drawing processing unit when it is confirmed that the progress is low.   The image forming apparatus according to claim 1, wherein the graphic information acquisition unit, the drawing processing progress confirmation unit, the graphic information storage processing unit, the information conversion unit, and the drawing processing unit are realized by different calculation units. . A processing amount calculation unit that calculates a processing amount of processing for generating the drawing information based on the graphic information stored in the storage medium;
The image forming apparatus according to claim 1, wherein the drawing processing progress confirmation unit confirms the progress of the drawing processing based on the calculated processing amount.   The drawing process progress confirmation unit calculates a remaining amount of the drawing process based on the calculated processing amount, and confirms the progress of the drawing process based on the calculated remaining amount. The image forming apparatus according to 3.   The image forming apparatus according to claim 4, wherein the drawing processing progress confirmation unit confirms that the progress is low when the calculated remaining amount is greater than a predetermined threshold.   The image forming apparatus according to claim 2, wherein the processing amount calculation unit calculates a processing amount of the drawing processing according to a calculation capability of the plurality of calculation units.   The processing amount calculation unit calculates the processing amount based on a variable element that varies according to the content of the drawing command and a fixed element that is determined by the performance of hardware that constitutes the image forming apparatus. The image forming apparatus according to claim 6.   The processing amount calculation unit calculates the variation element so that the contribution ratio to the entire variation element differs for each of the plurality of types of processing included in the drawing command according to the content of each of the plurality of types of processing. The image forming apparatus according to claim 7, wherein:   The image forming apparatus according to claim 1, wherein the drawing processing progress confirmation unit confirms the progress of the drawing processing based on the graphic information stored in the storage medium.   The image forming apparatus according to claim 1, wherein the information conversion unit executes part or all of scan line conversion when the information format of the graphic information is vector data.   11. The information conversion unit according to claim 1, wherein when the information format of the graphic information is image data, the information conversion unit executes part or all of color matching, CMYK conversion, and total amount regulation. Image forming apparatus. An image forming method for executing image processing for executing image forming output by a plurality of arithmetic means,
The drawing command acquisition unit acquires a drawing command obtained based on the page description language,
A graphic information acquisition unit acquires graphic information describing a graphic included in an image to be output based on the drawing command,
A graphic information storage processing unit stores the acquired graphic information in a storage medium,
A drawing processing unit generates drawing information for drawing the graphic based on the stored graphic information,
A drawing process progress confirmation unit confirms the progress of the drawing process for generating the drawing information when the graphic information is stored in the storage medium,
An image forming method characterized in that, when it is confirmed that the progress is low, the information conversion unit converts an information format of the graphic information to reduce a processing amount executed in the drawing processing unit. A control program for controlling an image forming apparatus capable of executing image processing for executing image forming output by a plurality of arithmetic means,
Obtaining drawing commands obtained based on the page description language;
Obtaining graphic information describing a graphic included in an image to be output based on the drawing command;
Storing the acquired graphic information in a storage medium;
Generating drawing information for drawing the graphic based on the stored graphic information;
Checking the progress of a drawing process for generating the drawing information when the graphic information is stored in the storage medium;
Control that causes the image forming apparatus to execute the step of reducing the amount of processing executed in the drawing processing unit by converting the information format of the graphic information when the progress is confirmed to be low program.

Images