JP2012221256A - Image processing system and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To parallelly interpret an image forming instruction in a page described in PDL and perform raster image data generation at high speed.SOLUTION: A PDL interpreter divides an image forming instruction in a page of PDL and allows interpretation processing parts to parallelly execute interpretation processing. The interpretation processing parts transform the image forming instruction into an object drawing instruction by using a relative drawing state attribute value, and passes the instruction to a renderer. The renderer parallelly generates intermediate data by a plurality of intermediate data generation parts and then performs coupling processing of the intermediate data. At the point when the coupling processing of the intermediate data ends, raster image generation processing is parallelly executed.

Description

  The present invention relates to an image processing apparatus and an image processing method, and more particularly to an image processing apparatus and an image processing method for generating image data by interpreting image forming instructions in a page described in a page description language in parallel.

  Data described in page description language (PDL) is received via a communication medium such as a network, is interpreted by a dedicated interpreter, RIP processing is performed to form a raster image, and a printer engine such as electrophotography or inkjet is used. A page printer that performs print output is widely known. A host application such as a printer driver is stored as an executable program in a memory in the PC, interprets the PDL in the PC, performs RIP processing for generating a raster image, and transmits the image to the printer.

  In PDL RIP processing, data analyzed by software processing in a PDL interpreter is passed to a renderer by hardware processing or software processing. The renderer creates intermediate data based on information received from the PDL interpreter, and generates a raster image for each of a plurality of scan lines or the entire page. Many printers and PCs have a multi-core and multi-CPU environment, and it is important to execute RIP processing in parallel and at high speed. Therefore, various parallel processing methods in the RIP system have been considered in order to increase the speed of the multi-core and multi-CPU.

  For example, Patent Document 1 proposes a method of performing parallel processing by a PDL interpreter and a renderer for each page. This speeds up the RIP system by dividing PDL data composed of a plurality of pages into pages and executing PDL interpreter interpretation processing and renderer raster image generation processing in parallel for each PDL page. Is realized.

  Patent Document 2 proposes parallel processing in units of drawing objects. In general PDLs such as Adobe PostScript and PDF, a plurality of drawing objects such as graphics, images, and text are defined with positional dependency such as overlapping. In the RIP system, the PDL interpreter takes these position dependencies into consideration and groups the drawing objects having no position dependency, that is, the drawing objects having no overlap, and passes the drawing objects to the rendering processing unit. This is a proposal for realizing high-speed processing by performing parallel rendering processing for each drawing object in units grouped by a rendering processing unit or a rendering processing control unit.

JP 2006-159738 A Japanese Patent Laid-Open No. 10-040360

  With the parallel processing in units of pages according to the invention of Patent Document 1, it is not possible to achieve high speed for single-page PDL data. Also, if a page with heavy processing exists, the load on the PDL interpreter processing for processing that page becomes relatively high and a critical path is formed, so that the speed of the entire RIP processing cannot be achieved. In the invention of Patent Document 2, the interpretation processing by the PDL interpreter is processed sequentially, and it is necessary to solve the position dependency by the interpretation processing of the PDL interpreter in advance, and it is expected that this processing will be loaded.

In order to solve the above problems, the present invention has the following configuration. That is,
A dividing unit that divides one page of PDL data described in a page description language into a plurality of divided parts;
Parallel interpretation means having a plurality of interpretation processing units for interpreting a page description language instruction included in the divided part and converting it into an object drawing instruction for each of the divided parts,
Intermediate data generation means having a plurality of intermediate data generation units for generating intermediate data from the object drawing command for each divided portion;
Intermediate data combining means for combining the intermediate data for each of the divided parts to create intermediate data for one page;
Parallel raster image generation means for dividing the combined intermediate data and generating a raster image in parallel for each of the divided portions.

Alternatively, according to another aspect, the present invention provides dividing means for dividing one page of PDL data described in a page description language into a plurality of divided portions;
A parallel having a plurality of interpretation processing units for interpreting a page description language instruction included in the divided part and calling an object drawing function together with an operand corresponding to the instruction for each of the divided parts. Interpretation means;
Intermediate data generation means having a plurality of intermediate data generation units for generating intermediate data according to the called object drawing function and operand for each divided portion;
Intermediate data combining means for combining the intermediate data for each of the divided parts to create intermediate data for one page;
Parallel raster image generation means for dividing the combined intermediate data and generating a raster image in parallel for each of the divided portions.

According to the present invention, it is possible to reduce the RIP processing time by dividing each page of PDL data into a plurality of divided portions and performing parallel processing on the divided portions. In particular, since the process of generating intermediate data from PDL data is also performed in parallel, the speed is further increased as compared with the prior art. In particular, it is possible to greatly reduce the RIP processing time of PDL data consisting of a single page and heavy processing PDL data having a large number of image forming instructions in the page.

The system configuration figure showing an example of the system configuration of the present invention. The figure explaining the processing flow of interpretation control. The figure explaining the image formation command division | segmentation in a page. The flowchart of an interpretation process part. The figure explaining the start position and the end position. The figure explaining the stack of a drawing state attribute. The figure explaining the object drawing command. The figure explaining the processing flow of the intermediate data generation part. Intermediate data schematic diagram. The processing flow of the intermediate data coupling unit. The figure which showed the coupling | bonding of the drawing state attribute stack. The figure which showed the example of the intermediate data coupling | bonding. The figure explaining the raster image generation process for every scan line.

[Embodiment 1]
The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. In FIG. 1, the drawing processing apparatus according to the present embodiment includes a PDL interpreter 11 and a renderer 12. The PDL interpreter 11 includes an interpretation control unit 13 and a plurality of interpretation processing units 14. The renderer 12 includes a plurality of intermediate data generation units 15, an intermediate data combination unit 16, a display list buffer (DL buffer) 17, a raster. An image generation control unit 18 and a plurality of raster image generation units 19 are included. The image processing apparatus can be realized by a general-purpose computer, and in particular, the above-described units can be realized by executing a program as illustrated in the computer. In this case, it is desirable that the processing units operating in parallel are executed in parallel by a plurality of processors. The program is stored in a file storage such as an HDD, and the program is loaded into a memory or the like and executed by the processor. As a result, a PDL interpreter or renderer can also be realized. Each processing unit operating in parallel is realized by two or more processor cores. Furthermore, a plurality of threads can be executed in parallel by each processor core, and each core can realize an interpretation processing unit by the plurality of threads.

  In this configuration, the PDL interpreter 11 takes up PDL data described in a page description language (PDL) format, that is, a page description language. The PDL data includes a plurality of image forming instructions and their operands. Typical PDLs include Adobe's PostScript (registered trademark), Portable Document Format (PDF), and Microsoft's XML Paper Specification (XPS), but the input PDL is not limited to this.

  The interpretation control unit 13 of the PDL interpreter divides the page of interest described in PDL into a plurality of portions, and the plurality of interpretation processing units 14 perform the interpretation processing of the image forming instructions included in the divided portions in parallel. Let it run. Basic and respective parts include a plurality of objects, but only one object may or may not be included. These divided parts are called divided parts. Each interpretation processing unit 14 converts the interpreted image formation command into an object drawing command which is an internal representation format, and passes it to the renderer 12. At this time, each interpretation processing unit 14 constructs an object drawing command using a relative drawing state attribute value from the interpretation start position.

  The object drawing command may be delivered in units of divided parts, but in this example, it is assumed to be performed in units of commands. The conversion and delivery to the object drawing command may be performed by a method of generating code and delivering it, but can also be realized by calling a function provided by the renderer. In the latter method, the interpreted image forming command is converted into intermediate data without waiting for the interpretation of the subsequent command. In the present embodiment, the procedure for converting to an object drawing command and transferring it to the renderer will be described as in the former, but the essence of the present invention is not impaired by either method.

  Here, the interpretation start position refers to the position within the page at the beginning of the divided portion that is the processing target of the interpretation processing unit. The drawing state attribute value includes various values that are referred to at the time of drawing such as CTM (coordinate transfer matrix), color space, color value, line width, and the like. The drawing state attribute value is stacked on the drawing state attribute value stack, and the position indicated by the stack pointer, that is, the drawing state attribute value at the top of the stack is used for drawing. The drawing state attribute value is determined in the middle of a page by being sequentially processed from the top in units of one page. However, in this embodiment, the page is divided into a plurality of parts. Therefore, when the object drawing command is generated by the PDL interpreter 11, the initial value of the drawing state attribute value stack is provisionally determined for each divided portion, and the stack operation and the drawing state attribute value are referred to. The “relative drawing state attribute value from the initial value interpretation start position” refers to a drawing state attribute value given by a drawing state attribute value stack provisionally defined in each divided portion. In this temporary stack, the value is stored for the attribute whose value is fixed, and the value indicating the hierarchy of the stack in which the attribute value should be stored is stored for the attribute that is not fixed. . This value is also called a relative drawing state attribute or a relatively expressed drawing state attribute value. The relatively expressed drawing state attribute value stack is determined before the raster image generation process by integrating the divided portions.

  The renderer 12 that has received the object drawing command uses a plurality of intermediate data generation units 15 to generate intermediate data such as a display list (DL) in parallel. The intermediate data generated at this time is based on the relative drawing state attribute and is stored in the DL buffer 17. Further, the intermediate data combining unit 16 performs a process of combining intermediate data in the DL buffer 17 generated by the intermediate data generating unit 15 and performs a process of resolving a relatively expressed drawing state attribute value. At the time when all the intermediate data are combined, the raster image generation control unit 18 uses a plurality of raster image generation units 19 for each area divided into tile units or band units based on the intermediate data in the DL buffer 17. Causes raster image generation to be executed in parallel. One page of raster image data is generated by the above processing.

  Such a process of converting an image formation command for each page of PDL into a raster image is repeatedly performed for all pages of PDL, thereby realizing a raster image generation process using PDL data as an input.

  As described above, the image processing apparatus includes two steps, ie, an object drawing command generation process by the PDL interpreter 11 and an intermediate data generation process by the renderer 12. That is, parallel interpretation processing of image forming instructions in a page by the PDL interpreter 11 and parallel raster image generation processing by the renderer 12. Hereinafter, two steps of the parallel interpretation process of the PDL interpreter 11 and the parallel raster image generation process of the renderer 12 will be described.

<Processing by the PDL interpreter 11>
First, details of processing of the interpretation control unit 13 and the plurality of interpretation processing units 14 which are steps of the PDL interpreter 11 will be described with reference to the drawings.

<Division processing of PDL data for one page>
FIG. 2 is a flowchart showing the processing flow of the interpretation control unit 13. In step S201, the interpretation control unit 13 reads input PDL data. In S202, the page configuration is interpreted with respect to the PDL data read in S201, and a list in which the page configuration included in the PDL is expressed by an array or the like is generated. In S203 and subsequent steps, interpretation processing for each page is performed based on the generated list. Note that an instruction written in PDL is called an image formation instruction, and is distinguished from an object drawing instruction.

  In S203, it is determined whether or not there is an unprocessed page. If there is no unprocessed page, the image generation process using PDL data as input is terminated. On the other hand, if there is an unprocessed page in S203, the page is regarded as the page of interest, and an image formation command for the PDL included in the page of interest is acquired in S204. The image formation command in the page may be compressed by the compression method determined by the specification depending on the specification of PDL, and in that case, decompression processing is performed in S204 and placed in the memory of the apparatus. In S205, the number of page divisions acquired in S204 is determined. The number of divisions may be determined statically according to the system core and CPU configuration. Further, it may be determined dynamically depending on the size of the page image formation command and the system load at that time. For example, if the system has a large number of CPUs and parallelism is high, the number of divisions is determined so as to increase the number of divisions and increase the parallelism of interpretation processing.

  In S206, page division processing according to the number of divisions determined in S205 is performed. The page division is expressed by determining a pointer or the like indicating the position of the start point and the end point with respect to an image forming command for one page arranged on the memory. That is, it can be said that the division referred to in this embodiment is to determine a division point. Since the end point of a certain divided portion is also the start point of the next divided portion, the division position in the page may be determined without determining the start point and the end point.

  FIG. 3 shows an example in which one page of PDL data is divided when PDF is adopted as the PDL. 301 is an image forming command for the entire page, and 302 is an example of dividing the entire page. In FIG. 3, two division points 321 and 322 are defined in the page. The division in S206 is performed without interpreting the image formation command. By dividing the size of one page of PDL data by the number of divisions determined in S205, the size of one divided portion is obtained. Further, the PDL data for one page is divided for each size of the obtained divided portion, and an index value indicating the number of divided portions from the head in the page, and a start point and an end point for the index value are determined. The index value of the divided portion corresponding to the head of the page is normally set to 1.

  In S207, it is confirmed whether the activation of the interpretation processing unit 14 for all the divided parts divided in S206 has been completed. If there is an unstarted interpretation processing unit 14, the process proceeds to S208, where the interpretation processing unit 14 is started up, and the corresponding PSL data is divided. Thereby, each divided part is processed in parallel. When each interpretation processing unit 14 is activated, an index value indicating a division portion to be processed by each interpretation processing unit 14 and a pointer indicating a start point and an end point, that is, a division position are passed to each interpretation processing unit 14. If it is determined in step S207 that activation of the interpretation processing unit 14 in all pages has been completed, the process returns to step S203 to process whether there is an unprocessed page. Thereafter, by repeating the above process for each unprocessed page, the page is divided for all the pages of the input PDL data, and subjected to parallel interpretation processing for each divided portion.

<Instruction interpretation processing>
FIG. 4 shows a flowchart of the interpretation processing unit 14 that is activated a plurality of times and executed in parallel. In step S401, the activated interpretation processing unit 14 calls a group start command from among the object drawing commands that are internal expressions representing the group start. That is, the group start command is output as the first command of the object drawing command group to be output and is input to the renderer 12. The object drawing command is a code as shown in FIG. 7 described later, and is an internal code generated by the interpretation processing unit 14. Any object drawing command may be used as long as the intermediate data generation unit 15 can process it. This group start command is given an index value of a divided portion divided from one page of PDL data processed by the interpretation processing unit. Thereby, the renderer 12 can determine the position in the page of the division part to be processed. Instead of outputting the object drawing command as, for example, a code, a function provided by the intermediate data generation unit 15 may be called together with an operand given to the function.

  In step S402, the interpretation processing unit 14 initializes the drawing state attribute stack. Since the stack is dynamically changed according to the original process, the state of the stack when starting the interpretation processing of each divided portion is equal to the state at the time when the processing of the immediately preceding divided portion is completed. Therefore, the drawing state attribute stack is initialized with GS0 indicating the initial relative value at the start of interpretation processing. The initial relative value GS0 represents a relative value to the drawing state attribute stack of the interpretation control unit 14 whose index value is 1 smaller. That is, if the interpretation process is started from the top of the page, the relative pointer to the drawing state attribute stack at the time when the process reaches the true start point of the divided portion is shown. The stack initialized for each divided portion is referred to as an initial stack in the divided portion. This is the highest level of the drawing state attribute stack at the end of the interpretation processing of the immediately preceding divided portion. It is assumed that the top of the stack is indicated by the pointer (or stack pointer) of the stack, and the interpretation for each image forming instruction is started in S403. The stack is held in the interpretation processing unit 14 in, for example, a local memory.

  In the interpretation process, the image forming instructions are sequentially interpreted from the reference pointer of the start point of the PDL data placed on the memory of the apparatus. At this time, if the character to be referred to at the start point is not a delimiter character determined by the PDL specification, the pointer is moved after the delimiter character, and interpretation processing is started thereafter. For example, the delimiter character delimits operators and operands constituting the image forming command, delimits operands, or delimits operators. Further, the interpretation processing here always targets a set of a reserved word operator and an operand of the operator in the PDL specification. The number of operands for the operator is determined for each operator, and when the number of operands is different from the prescribed number, it is assumed that there is a start point in the middle of the image formation command, and the command immediately after the operator ends is the true start point. Continue the interpretation process. Thus, the true start point is determined at the start of interpretation in S403. The operator is, for example, a character string reserved in advance, and the operator's code can be determined to be an operator based only on the character string. For this reason, even if it is expressed in binary like a color value, it can be distinguished from the operator by being expressed as a character code indicating a number or a character as an operand, for example.

  FIG. 5 shows an example of the division points in step S206 and the true start point and true end point. A divided portion 501 is a divided portion made up of an image formation command assigned to the interpretation processing unit 15, and the start point 502 indicates the beginning thereof. By parsing the image formation command while paying attention to the characters sequentially from the start point 502, "re", which is the operator of the rectangle formation command, is found as the first operator in the divided portion. In this example, it is assumed that codes other than the delimiter and the operator are regarded as operands, and the operand is a syntax preceding the operator. Therefore, when scanning the operand, the length of the operand is counted, for example, in units of bytes. If an operator is found, it is determined whether the number of operands counted so far matches the predetermined number of operands for the operator. For example, in the example of FIG. 5, the number of operands corresponding to the operator “re” is checked. The number of operands is immediately determined from, for example, a table in which the number of operands is associated with each operator. The operand of the operator “re” is determined to be 4 according to the PDL specification, whereas the number of operands from the start point 502 to the operator “re” is 2. Therefore, assuming that the start point 502 refers to the middle of the operand, the true start point 503 is determined immediately after the first found operator, in this example, the operator “re”, and the position is stored. Similarly, for the end point 504, a true end point 505 with the operator as a break is determined and stored. Since the determination of the true division point is performed in the same manner in the divided parts adjacent to each other, the true division point matches in each divided part.

  If the true division point is determined, in S404 and after, interpretation is performed for each operator of the image formation commands focused on starting from the true start point. In step S405, whether the focused image formation command is a command related to drawing of objects such as text, images, and graphics (this command is referred to as an object drawing image formation command to distinguish it from the object drawing command). Determine whether. If it is determined in S405 that the focused image formation command is not an object drawing image formation command, the drawing state attribute value is updated in S406, assuming that the image formation command is an update of the drawing state attribute value.

  FIG. 6 shows an example of a stack of drawing state attribute values. The stack initialized in S402 indicates a relative value to the top data of the drawing state attribute value stack when execution of the image forming command belonging to the divided portion immediately before the divided portion of the PDL data to be processed is completed. ing. The relative value may be information that can identify the immediately preceding divided portion, and may be called a temporary value. The stack initialized in S402 is referred to as an initial stack in the divided part. The stack level 601 indicates that initialization has been performed with GS0. The value GS0 indicates the continuity from the drawing state attribute value stack of the divided part immediately before the divided part. When the drawing state attribute value is updated by a subsequent image forming command, the top data of the drawing state attribute stack is changed according to the image forming command. The stack 602 is an example in which the color space of the drawing state attribute is updated by a push instruction, and the stack 603 is an example in which the line width value of the drawing state attribute of the top data of the stack is updated. Thus, the value of the drawing state attribute value stack is updated by the image forming command.

  On the other hand, when the stack value before the initial stack in the divided portion is referred to by the pop instruction twice or more for the stack initialized in step S601, the stack cannot be popped. Therefore, as indicated by reference numeral 604, the stack is updated with an expression that relatively indicates the reference destination. For example, when a pop instruction is read out and executed from the state of the initial stack 601 in the divided portion, the content is rewritten from GS0 to an expression (for example, a code) GS1 that refers to the next stage. The subscript [1] of GS1 indicates that it is one lower than the stack level initial stack to be referred to. If there is a pop instruction, GS1 is further rewritten to GS2 indicating a lower level. The value GS2 of the stack 604 in FIG. 6 updated in this way is a reference to the value of the stack that is two steps lower than the highest stack. When referring to a stack level below the initial stack 601 in the divided portion, if there is a push instruction, the updated value of the drawing state attribute stack is stacked above the drawing state attribute stack. A stack level 605 indicates that a drawing state attribute whose color value is updated is stacked on the stack level 604 by a push instruction.

  Returning to FIG. 4, it is determined in step S405 whether or not the image formation command focused on is an object drawing image formation command. If it is an object drawing image formation command, an object drawing command corresponding to the image formation command is called in S407. That is, an object drawing command corresponding to the fetched image forming command is output together with its operand and delivered to the renderer 12. The drawing state attribute value at this time uses the highest value of the drawing state attribute stack. If the data 605 is at the top, GS2, which is a relative stack reference, becomes a drawing state attribute value other than the color value. In step S408, it is determined whether the interpretation process has already exceeded the end point. If the end point has not been exceeded, the process returns to S404, and the interpretation process is continued by paying attention to the next image formation command. If the end point has already been exceeded in S408, a group end instruction is called in S409. That is, the group end instruction is delivered to the renderer 12. At that time, the drawing state attribute value stack level at that time is added as an operand. Then, the interpretation processing for the divided portion of the PDL data to be processed is finished.

  FIG. 7 shows an example of a series of object drawing command calls of the interpretation processing unit 14. Reference numeral 701 denotes a group start command that is called when interpretation starts. Reference numeral 702 denotes an object drawing command for drawing graphics. In FIG. 7, relative values GS0 are passed to the renderer 12 for CTM and color values. However, values for line width and color space are determined at the time of interpretation of this command, and the values are handed over. Further, reference numeral 703 denotes a group end command at the end of interpretation, and a drawing state attribute value stack (GS0-GS3 in FIG. 7) at the end of interpretation processing is added. In this way, the interpretation processing unit 14 performs interpretation processing up to the operator break after the end point, and implements an object drawing command call to the renderer 12 based on relative drawing state attribute values.

<Processing of renderer 12>
Next, the steps of the renderer 12 will be described. FIG. 8 shows a processing flow diagram by one of the plurality of intermediate data generation units 15 processed in parallel. FIG. 8 assumes that the object drawing command from the interpretation processing unit 11 starts with a group start command and ends with a group end command. First, the type of the object drawing command is determined, and the process branches to processing according to the type. You may comprise. In that case, every time an object drawing command is input, the intermediate data generation unit 15 executes processing according to the type of the command.

  In FIG. 8, the activated intermediate data generation unit 15 first receives a group start instruction from the corresponding interpretation processing unit 14 in S801, and starts an intermediate data generation process such as Display List. In S802, an intermediate data area (DL buffer 17) is secured in the DL buffer 17, and the index value added to the group start instruction in S801 is given to the intermediate data. That is, the index value is written in the DL buffer 17. In step S803, an object drawing command is received from the interpretation processing unit 14. In step S804, it is determined whether the object drawing command received in step S803 is a group end command. If the object drawing command is not a group end command, an object is added to the intermediate data in the DL buffer 17 in step S805 as an object drawing command for drawing graphics, images, text, and the like. FIG. 9 shows a schematic diagram of the intermediate data. The intermediate data 901 is configured by a list based on the scan line 902. Each object such as a graphic, an image, and a text is represented by an edge list 903 that means a contour, and each edge hangs from a corresponding scan line list 902. Furthermore, each edge list has a drawing attribute 904 such as a paint color and a line width of the object. Here, when the interpretation processing unit 14 designates a relative drawing state attribute, the intermediate data generation unit 15 generates an edge list 903 and a drawing attribute 904 of intermediate data in the DL buffer 17 based on the relative values. Here, for drawing state attribute values (for example, CTM) indicating coordinate movement, intermediate data is generated assuming that the relative drawing state attribute is origin movement. As a result, the intermediate data 901 becomes a list with respect to the relative scan lines based on the start of the intermediate data generation. When an object is added to the intermediate data already generated in S805, the process returns to S803 and the reception of the object drawing command is repeated. If the object drawing instruction is a group end instruction in S804, the drawing state attribute value stack array added to the group end instruction is stored in the DL buffer 17 in S806, and the intermediate data combining unit 16 ends in S807. And the process of the intermediate data generation unit 15 is terminated.

<Intermediate data join processing>
A processing flow of the intermediate data combining unit 16 is shown in FIG. The intermediate data combining process is a process of linking the intermediate data generated for each divided part obtained by dividing one page to determine an undefined drawing state attribute value. Note that intermediate data generated in association with a certain index value is called intermediate data of that index value.

  In S1001, the index value of the intermediate data to be combined is initialized. The initial value is an initial value when the PDL data is divided, and is normally set to 1. In step S <b> 1002, the intermediate data combining unit 16 waits for completion of the intermediate data generation process for the index value initialized in step S <b> 1001. In S1003, the index value is incremented, and the end of the intermediate data generation process corresponding to the index value is awaited. In S1004, the drawing state attribute value stack in the intermediate data of the current index value is combined with the drawing state attribute value stack of the intermediate data in S1002. An example of the rendering state attribute value stack combining process is shown in FIG. The stack 1101 is a drawing state attribute value stack before combining and includes an undefined value. The stack 1102 is a drawing state attribute value stack to be combined, and is already combined with a stack having an index before that. If the head, that is, the index value is 1, it is determined without combining. A stack 1103 is a combined drawing state attribute value stack. The “joining target” and “before joining” can be specified by index values. Since the divided parts to be combined are adjacent to each other, the index values are continuous, and the divided part having the smaller index value can be defined as the object to be combined, and the larger one can be defined as being before combining.

  Since the lowest layer stack array in the drawing state value stack 1102 to be combined is GS0 indicating the top of the drawing state attribute value stack 1101 before combining, GS0 is replaced with the top stack array 1104 of the drawing state stack 1101 before combining. , The bond is made. Thereafter, all the attribute values of GS0 in the upper stack array in the combining target drawing state attribute value stack 1102 are replaced with the highest value that is the reference relative value of the drawing state attribute value stack before combining. For example, GS0 of the second line width of the drawing state attribute value stack before combination is replaced with the value 4 at the top of the drawing state attribute value stack before combination. When all the relative values are replaced, the combined drawing state attribute value stack 1103 can be obtained. In the combination of drawing state attribute stacks in S1004, a relative stack start position 1105 corresponding to GS0 of the combined drawing state attribute stack is held. In this example, only GS0 is shown, but the replacement is performed in the same way when referring to a lower level.

  In step S1005, based on the drawing state stack combined in step S1004, a process for replacing the relative drawing state attribute value in the intermediate data is performed. The drawing state attribute value described as a relative value is replaced with reference to the stack 1103 in FIG. 11 to obtain intermediate data after replacement. As the drawing state attribute value in which the relative value in the intermediate data is described, the value after replacement is determined relative to the relative stack start position 1105. For example, GS0 indicates the value of the relative stack start position, and GS2 is replaced with a value two steps lower than the relative stack start position.

  As for the intermediate data after the replacement, the absolute coordinates for the page can be obtained by replacing the drawing state attribute value related to the coordinate movement. That is, the movement amount can be calculated by multiplying the intermediate data created at the relative position by the CTM of the determined drawing state attribute value indicating movement. In S1006, the combination processing of the intermediate data to be combined with the intermediate data before combining is performed in consideration of the movement amount for the intermediate data to be combined. FIG. 12 shows an example of the intermediate data combining process. 1201 is intermediate data before combining. In general, position dependency such as overlap in PDL is arranged in the order of image formation commands of each object. That is, when an object defined earlier and an object defined later have an overlap, the object defined later is placed at a higher level. Since the definition is followed by the description order, the intermediate data having a smaller index value, that is, the intermediate data “to be combined” is defined before the intermediate data “before combining”. Therefore, the intermediate data 1203 after combining is realized by adding the intermediate data 1202 to be combined replaced in S1005 to the end of the edge list based on each scan line of the intermediate data 1201 before combining. it can. Intermediate data 1203 represents the intermediate data after combination. In S1007, it is determined whether the intermediate data to be combined in S1006 is the final intermediate data of the page. If it is the last intermediate data, the process proceeds to S1008, a raster generation start command is sent to the raster image control unit 18, and the intermediate data combining process is terminated. If it is not the last intermediate data in S1007, the process returns to S1003 and the intermediate data combination is repeated until the entire page combination process is completed.

<Raster image generation processing>
Hereinafter, the raster image generation processing in the renderer 12 will be described in detail with respect to the raster image generation unit 19 that is processed in parallel with the raster image control unit 18. The raster image control unit 18 starts generating the raster image when the intermediate data combining unit 16 finishes generating the intermediate data for each page. First, the raster image control unit determines the number of divisions for the entire generated page. In general, for raster generation division, parallel raster image generation is performed by dividing into regions of tile units, such as division in both x-axis and y-axis directions, with each scan line or the upper left of the page as the origin. When parallel raster generation is performed in units of a plurality of scan lines, the number of scan lines required for the entire page is obtained from the resolution of the raster image to be generated and the page size. If the entire page has 7000 scan lines and the number of scan lines processed by each raster image generation unit 19 is 50, the number of divisions is 140. The raster image control unit 18 activates a raster image generation unit 19 in order to generate a desired raster image. The raster image generation unit 19 reads intermediate data stored in the DL buffer 17. At this time, the raster image generation unit 19 reads the intermediate data for the scan line necessary for the scan line to be generated. The raster image is generated by resolving the edge, paint color, and overlap for each scan line. FIG. 13 shows an example of generating each scan line. A scan line 1301 is a scan line of interest. In the scan line 1301, the presence / absence of an edge in the x-axis direction is checked. On the scan line 1301, there are edges of a graphic 1302 and an image object 1303.

  Since there are no objects in the areas 1304 and 1307, they are painted in the background color. An area 1305 is an area where a graphic object 1302 is defined, and the color of each pixel is determined by the paint color of the graphic object. An area 1306 is an area where the graphic object 1302 and the image object 1303 having transparency above it overlap. In this region, a final pixel value is obtained for each pixel by a composition result using the fill color of the graphic object, the color value of each pixel of the image, and the transparency. This synthesis method is defined in each PDL specification, and various synthesis methods are defined as blend modes in PDF. A raster image for each scan line is obtained by sequentially determining the value of each pixel in such a scan line. By performing this operation for all the scan lines, a raster image having a desired number of scan lines can be obtained. The raster image generation unit 19 operates in parallel with such a raster image generation process to output a raster image of the entire page.

  According to the above embodiment, in an image processing apparatus that generates a raster image using PDL as an input, the PDL interpreter performs parallel interpretation of image forming instructions in each page of the PDL, and performs intermediate data generation and raster image generation in the renderer. Even in parallel. As a result, the RIP processing time can be shortened in a multi-CPU and multi-core environment. In particular, it is possible to greatly reduce the RIP processing time of a PDL consisting of a single page or a PDL in which a specific page with a heavy processing having a large number of image forming instructions exists in the page.

[Modification 1]
In the processing of the PDL interpreter 11 described in the embodiment, the processing for each page is processed sequentially. The processing of the entire PDL has been speeded up on a page-by-page basis, but speeding up of raster generation of the entire PDL has not been considered. Therefore, the interpretation control unit 13 also performs page division at the same time and performs parallel processing on each page, thereby further increasing parallelism and generating a raster image at high speed.

[Modification 2]
The division of the image forming command for each page of the interpretation control unit 13 described in the embodiment is equally divided by the number of divisions with respect to the size of the image forming command. For this reason, it may be considered that the intermediate data combining unit 16 frequently waits for completion of processing of the desired intermediate data generating unit 15. Therefore, the interpretation control unit 13 does not divide evenly according to the number of divisions, but rather divides the portion of the page close to the start of the image formation command into smaller sizes, thereby waiting for the intermediate data combining unit 16 to wait. Can be suppressed.

[Modification 3]
In the joining process of the intermediate data joining unit 16 described in the embodiment, the joining process is sequentially performed on the intermediate data from the smallest index value. For this reason, if the generation of specific intermediate data is slow because the divided image formation command is complicated, a waiting for completion of the processing occurs. Therefore, the intermediate data join processing is completed after the intermediate data generation unit 15 finishes. By combining the intermediate data having the adjacent index values, the waiting time is shortened and the intermediate data join generation is performed at higher speed. Is possible.

[Modification 4]
In the first embodiment, after dividing the page appropriately, each divided part is parsed to determine the instruction break. On the other hand, the process of dividing the PDL for one page of interest can be configured so that the interpretation control unit 13 performs the processing in a unified manner including the determination of the division position. The processing after the division position determination is the same as that in the above embodiment.

[Other Examples]
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (11)

A dividing unit that divides one page of PDL data described in a page description language into a plurality of divided parts;
Parallel interpretation means having a plurality of interpretation processing units for interpreting a page description language instruction included in the divided part and converting it into an object drawing instruction for each of the divided parts,
Intermediate data generation means having a plurality of intermediate data generation units for generating intermediate data from the object drawing command for each of the divided portions;
Intermediate data combining means for combining intermediate data for each of the divided parts to create intermediate data for one page;
An image processing apparatus comprising: a parallel raster image generating unit configured to divide the combined intermediate data and generate a raster image in parallel for each divided part. When each of the interpretation processing units refers to a drawing state attribute value defined in a divided part before the divided part targeted by the interpretation processing unit, a temporary drawing state indicating a reference destination in the drawing state attribute value Assign an attribute value and convert it to the object drawing command,
The intermediate data combining means combines intermediate data for each of the divided portions, replaces the temporary drawing state attribute value assigned to the divided portion with a drawing state attribute value of a reference destination, 2. The image processing apparatus according to claim 1, wherein intermediate image data is created.   3. The image processing apparatus according to claim 1, wherein the intermediate data combining unit combines the intermediate data related to the plurality of divided portions generated by the intermediate data generating unit in order within the page of the divided portion. .   The intermediate data combining means repeats combining intermediate data related to a plurality of divided portions generated by the intermediate data generating means, regardless of the order of the divided portions in the page, by combining intermediate data related to adjacent divided portions. The image processing apparatus according to claim 1, wherein intermediate data for one page is combined.   5. The image processing apparatus according to claim 1, wherein the parallel interpretation unit moves a division position of the division part in accordance with a division of an image formation command of the PDL data. A dividing unit that divides one page of PDL data described in a page description language into a plurality of divided parts;
Parallel interpretation means having a plurality of interpretation processing units for interpreting a page description language instruction included in the divided part and converting it into an object drawing instruction for each of the divided parts,
Intermediate data generation means having a plurality of intermediate data generation units for generating intermediate data from the object drawing command for each of the divided portions;
Intermediate data combining means for combining intermediate data for each of the divided parts to create intermediate data for one page;
A program for causing a computer to function as parallel raster image generation means for dividing the combined intermediate data and generating a raster image in parallel for each divided portion. When each of the interpretation processing units refers to a drawing state attribute value defined in a divided part before the divided part targeted by the interpretation processing unit, a temporary drawing state indicating a reference destination in the drawing state attribute value Assign an attribute value and convert it to the object drawing command,
The intermediate data combining means combines intermediate data for each of the divided portions, replaces the temporary drawing state attribute value assigned to the divided portion with a drawing state attribute value of a reference destination, The program according to claim 6, wherein intermediate data is created.   The program according to claim 6 or 7, wherein each of a plurality of processors of the computer is caused to function as the plurality of interpretation processing units and the plurality of intermediate data generation units. A dividing step in which a dividing unit of the image processing apparatus divides one page of PDL data described in a page description language into a plurality of divided parts;
A parallel interpretation step in which a parallel interpretation unit of the image processing apparatus interprets a page description language instruction included in the divided part and converts it into an object drawing instruction in parallel for each of the divided parts; ,
An intermediate data generation step of generating intermediate data from the object drawing command in parallel for each of the divided portions, by the intermediate data generation means of the image processing device;
An intermediate data combining step of combining intermediate data for each of the divided portions to create intermediate data for one page;
An image processing method comprising: a parallel raster image generating means for splitting the combined intermediate data and generating a raster image in parallel for each of the divided portions; . In the parallel interpretation step, when a drawing state attribute value defined in a divided part before the divided part is referred to in processing of one divided part, a temporary drawing state attribute indicating a reference destination in the drawing state attribute value Assign a value and convert it to the object drawing command,
In the intermediate data combining step, intermediate data for each of the divided portions is combined, the temporary drawing state attribute value assigned to the divided portion is replaced with a drawing state attribute value of a reference destination, and one page worth The image processing method according to claim 9, wherein intermediate data is created. A dividing unit that divides one page of PDL data described in a page description language into a plurality of divided parts;
A parallel having a plurality of interpretation processing units for interpreting a page description language instruction included in the divided part and calling an object drawing function together with an operand corresponding to the instruction for each of the divided parts. Interpretation means;
Intermediate data generation means having a plurality of intermediate data generation units for generating intermediate data according to the called object drawing function and operand for each of the divided portions;
Intermediate data combining means for combining intermediate data for each of the divided parts to create intermediate data for one page;
An image processing apparatus comprising: a parallel raster image generation unit configured to divide the combined intermediate data and generate a raster image in parallel for each divided part.

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