JP2019074916A - Host device, system, method, and program - Google Patents

Abstract

To prevent incorrect drawing due to bit precision down in an environment where it is necessary to cut down the bit precision of affine coefficients due to performance limitation on a rendering device.SOLUTION: A host device creates, based on PDL data, intermediate data necessary for creating a raster image with a rendering device. The host device comprises: detection means for detecting whether or not incorrect drawing with image object data occurs based on the image object data included in the PDL data, bit precision that can be processed by the host device, and bit precision that can be processed by the rendering device; conversion means for converting the image object data when the detection means detects the occurrence of the incorrect drawing; and creating means for creating the intermediate data on the basis of the converted image object data.SELECTED DRAWING: Figure 4

Description

  The present invention relates to the technology of rendering processing.

  In the rendering process, bitmapped image data (raster image) is created based on print data (referred to as PDL data) described in PDL (Page Description Language). At this time, analysis processing such as what drawing object is included in the PDL data is performed, and intermediate data to be subjected to rendering processing is created based on the analysis result. The drawing objects include image objects, line objects, fill objects, gradation objects, and the like. For example, if the drawing object is an image object, the intermediate data may be an image object information, an original image, and an affine matrix for determining how to scale, rotate, or move the original image. The content is described based on the combination with

  Intermediate data is passed to a renderer such as a hardware renderer or a software renderer. The renderer creates a raster image based on the received intermediate data. At this time, a rendering process based on a combination of an original image and affine coefficients is performed on an image object.

  In general, a hardware renderer is capable of processing faster than a software renderer because it is a dedicated ASIC that takes a series of processes to receive intermediate data and create a raster image based on the received intermediate data. ing. By installing a hardware renderer on the printer, the user can expect to enjoy a faster printing experience. However, the more the bit precision that can be processed by the hardware renderer and the more the attributes of the drawing object that can be processed, the larger the circuit size of the computing unit becomes, which is disadvantageous in cost. Therefore, the hardware renderer designer estimates in advance how much bit precision should be, and then limits the bit precision handled by the hardware renderer or processes by the hardware renderer Limit the possible drawing commands.

  In rendering processing using a hardware renderer, intermediate data to be input to the hardware renderer needs to be created in advance in a format that can be processed by the hardware renderer on the host device side. For example, if there is a limit to the bit precision of affine coefficients that can be processed by the hardware renderer, the host device performs adjustment such as cutting off the lower bits of the affine coefficients, and then performs intermediate processing based on the adjusted contents. You have to create data.

  Patent Document 1 discloses that a hardware renderer and a software renderer are used properly according to a draw command, and specifically, when a draw command for drawing a tint block pattern is received, a rendering process is performed using the hardware renderer. It is disclosed to do.

JP, 2012-249171, A

  However, Patent Document 1 does not disclose a method for preventing improper drawing that may occur due to bit precision reduction based on the performance of a rendering device such as a hardware renderer, which is executed at the time of creation of intermediate data.

  Therefore, in view of the above problems, it is an object of the present invention to prevent improper drawing caused by bit precision reduction in an environment where bit precision of affine coefficients must be cut down due to performance limitation of a rendering apparatus.

  The present invention is a host device that creates intermediate data necessary for creating a raster image in a rendering device based on PDL data, and is capable of processing image object data included in the PDL data and the host device A detection unit that detects whether or not the drawing of the image object data occurs based on the bit accuracy and the bit accuracy that can be processed by the rendering device; and the detection unit detects the generation of the drawing that is incorrect The host device is characterized by comprising: conversion means for converting image object data; and creation means for creating the intermediate data based on the converted image object data.

  According to the present invention, in an environment where it is necessary to cut down on the bit precision of affine coefficients due to the performance limitation of the rendering apparatus, it is possible to prevent incorrect drawing caused by the downscaling of the bit precision.

Configuration of Rendering System in Embodiment 1 Block diagram of host device in the first embodiment Block diagram of rendering apparatus in embodiment 1 Block diagram showing the functional configuration of the host device in the first embodiment Block diagram showing the functional configuration of the rendering device in the first embodiment Illustration of image reduction by application of affine matrix Illustration of bit precision reduction of affine coefficients Explanatory drawing of pre-rendering processing using affine coefficients with different bit precision Explanatory drawing of comparison of the pixel value of a pre-rendering image Illustration of conversion of image object data Flowchart of Intermediate Data Creation Processing in Embodiment 1 Flowchart of Pixel Deviation Detection Process in Embodiment 1 An illustration of pre-rendering processing when different affine matrices are applied to the original image An explanatory view of a pixel to be compared in the pixel shift detection process in the second embodiment Flowchart of Pixel Deviation Detection Process in Embodiment 2 Block diagram showing the functional configuration of the host device in the third embodiment Flowchart of Intermediate Data Creation Process in Embodiment 3 Flowchart of Original Image Determination Process in Embodiment 3

Example 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are specific examples of the present invention, and therefore, various technically preferable limitations are added. However, the embodiments are not limited to the following embodiments or other specific methods as long as the idea of the present invention is followed.

<About the system configuration>
Hereinafter, the configuration of the rendering system in the present embodiment will be described using FIG. As shown, this system has a host device 101 and a rendering device 103 connected via a network 102. The host device 101 creates intermediate data based on the PDL data, and transmits the created intermediate data to the rendering device 103 via the network 102. The network 102 may be in any form as long as it can transmit intermediate data. For example, a wireless LAN, a wired LAN, a USB cable, or the like can be used as the network 102. The rendering device 103 creates a raster image by performing a rendering process on intermediate data transmitted via the network 102.

<About the configuration of host device>
Hereinafter, the configuration of the host apparatus 101 in the present embodiment will be described with reference to FIG. The host device 101 includes an input / output (I / O) device 202, a CPU 203, a RAM 204, a network interface (hereinafter, the interface is abbreviated as I / F) 205, and an external storage device 206. These components are connected by a data transfer bus 207 and can transmit and receive data to and from each other. As the host device 101, any device having the above-described components can be used. For example, a PC, a server, a smartphone, a tablet, or the like can be used.

  An input / output (I / O) device 202 performs data input / output processing. Examples of data input sources include various media capable of storing data, such as CDs, DVDs, USB memories, and SD cards. Also, as the data output destination, in addition to the above-mentioned media, a printer or the like can be mentioned. In this embodiment, the input / output (I / O) device 202 is used when inputting PDL data to the host device 101 or when outputting intermediate data from the host device 101.

  The CPU 203 executes arithmetic processing. Specifically, the CPU 203 executes various arithmetic processing such as analysis processing of PDL data and creation processing of intermediate data. The CPU 203 is responsible for processing in a PDL data interpretation unit 402, an intermediate data generation unit 403, a pixel shift control unit 404, a comparison image generation unit 405, a pixel shift detection unit 406, and an image object data conversion unit 407 described later (see FIG. 4). .

  The RAM 204 is used for temporary storage of data. In the present embodiment, PDL data and temporary variables are stored in the RAM 204, and a program for executing processing in the present embodiment described below is loaded into the RAM 204 and executed by the CPU 203. The RAM 204 can function as a print data storage unit 401 or an intermediate data storage unit 409 described later (see FIG. 4).

  The Network I / F 205 is connected to a LAN such as a wired LAN or a wireless LAN, and is used to transmit and receive data to and from an external device. For example, the host apparatus 101 receives PDL data transmitted from an external device such as a server via the Network I / F 205. Also, the host device 101 transmits intermediate data derived by analyzing the received PDL data to the rendering device 103 via the Network I / F 205.

  The external storage device 206 is mainly used for persistent data storage, and is used as a storage destination of programs and intermediate data for executing the processing in the present embodiment described below. Data that is too large to be stored in the RAM 204 may be temporarily saved to the external storage device 206. For example, the external storage device 206 may be responsible for storing pre-rendered images in the pre-rendered image storage unit 408 described later. The external storage device 206 can also function as the print data storage unit 401 or the intermediate data storage unit 409 (see FIG. 4).

<About the configuration of the rendering device>
Hereinafter, the configuration of the rendering device 103 will be described using FIG. The rendering device 103 includes a CPU 302, a RAM 303, a network I / F 304, an external storage device 305, and an ASIC 306. These components are connected by a data transfer bus 307 and can send and receive data to and from each other. As the rendering device 103, any device having the above-described components can be used, and for example, a PC, a server, a smartphone, a tablet, or the like can be used.

  The CPU 302 executes arithmetic processing. Specifically, the CPU 302 executes the program loaded into the RAM 303 to execute the rendering process in the ASIC 306 on the intermediate data input to the rendering device 103.

  The RAM 303 is used for temporary storage of data. In the present embodiment, intermediate data and temporary variables are stored in the RAM 303, and a program for executing processing in the present embodiment described below is loaded to the RAM 303 and executed. The RAM 303 can function as an intermediate data storage unit 501 described later (see FIG. 5).

  The Network I / F 304 is connected to a LAN such as a wired LAN or a wireless LAN, and is used to transmit and receive data with an external device. For example, the rendering device 103 receives intermediate data transmitted from the host device 101 via the Network I / F 304, and externally generates a raster image created based on the received intermediate data via the Network I / F 304. Send to device.

  The external storage device 305 is mainly used for permanent data storage, and in this embodiment, it is used as a storage destination of a program, intermediate data, and raster image for executing the processing in this embodiment described below. . Data that is too large to be stored in the RAM 303 may be temporarily saved in the external storage device 305. The external storage device 305 can function as an intermediate data storage unit 501 and a raster image storage unit 503 described later (see FIG. 5).

  The ASIC 306 creates a raster image by performing rendering processing on the intermediate data. The ASIC 306 is responsible for the processing in the rendering processing unit 502 described later (see FIG. 5).

<Functional Configuration of Host Device>
Hereinafter, the functional configuration of the host apparatus 101 in the present embodiment will be described with reference to FIG. FIG. 4 is a block diagram showing a functional configuration of the host apparatus 101 in the present embodiment.

  As described above, the CPU 203 executes the program loaded into the RAM 204, but here shows the case of executing the program 410. Thus, the PDL data interpretation unit 402, the intermediate data generation unit 403, the pixel shift control unit 404, the comparison image generation unit 405, the pixel shift detection unit 406, the image object data conversion unit 407, and the pre-rendered image storage And the unit 408 is realized. The host device 101 further includes a print data storage unit 401 and an intermediate data storage unit 409.

  The print data stored in the print data storage unit 401 includes PDL data and information of a rendering system to be used (referred to as rendering system information). The PDL data describes information on drawing objects such as image objects, line objects, and filling objects. The rendering system information also includes information on the rendering system, specifically, for example, the bit precision of affine coefficients that can be handled by the ASIC mounted on the rendering device 103.

  The PDL data interpretation unit 402 executes analysis processing on PDL data. Through this analysis process, information such as the number of pages of a document, the size of a page to be rendered, and information for specifying the type of an object included in the page (that is, attribute information) are read from PDL data .

  The intermediate data generation unit 403 generates intermediate data based on the PDL data. The intermediate data generation unit 403 also executes processing relating to intermediate data generation, such as a request for pixel shift detection to the pixel shift control unit 404.

  The pixel shift control unit 404 causes the comparison image generation unit 405 and the pixel shift detection unit 406 to execute pixel shift detection processing as necessary. At this time, the pixel shift control unit 404 passes, to the comparison image creation unit 405, image object data composed of the original image and the affine matrix and information on bit accuracy of affine coefficients that can be handled by the rendering device 103. In addition, the pixel shift control unit 404 causes the image object data conversion unit 407 to perform conversion processing of image object data, as necessary, based on the result of the pixel shift detection processing.

  The comparison image creation unit 405 creates a pre-rendered image used in the pixel shift detection processing by applying an affine matrix to the original image. The pre-rendered image created by the comparison image creation unit 405 is stored in the pre-rendered image storage unit 408.

  The pixel misalignment detection unit 406 compares the two pre-rendered images created by the comparison image creation unit 405 and determines whether pixel misalignment has occurred (that is, incorrect drawing may occur if the image object data is not corrected). Then, the determination result is returned to the pixel shift control unit 404. The pixel shift control unit 404 instructs the image object data conversion unit 407 to convert the image object data according to the determination result (specifically, when the pixel shift occurs). The image object data conversion unit 407 converts image object data in accordance with this instruction.

<On the Application of Affine Matrices>
The affine matrix is a matrix for determining how to scale, rotate, and move the original image. FIG. 6 shows how the original image is reduced to a half size image by applying an affine matrix. In the reduction process, when determining the value of the pixel at the coordinates (x ′, y ′) of the image after reduction 603, the value of the pixel at which coordinate (x, y) of the image before reduction (original image) 601 is referred You need to decide what to do. Hereinafter, the pixel to be referred to is referred to as a "reference pixel".

  The coordinates (x, y) of the reference pixel are obtained using the following equations (1) to (3) using the coefficients a, b, c, d of the inverse affine transformation matrix 602.

The value of the pixel at the coordinates (x, y) of the pre-reduction image 601 determined using the above equations (1) to (3) is the value of the pixel at the coordinates (x ′, y ′) of the after-reduction image 603 It becomes a value. However, coordinate values x and y of the reference pixel are not necessarily integers. When at least one of x and y is a decimal, an integer value closest to the value is used instead of the decimal value.

  In this specification, prior to rendering processing in the rendering device 103, processing for applying an affine matrix to the original image on the host device 101 side to create a pre-rendering image is referred to as "pre-rendering processing".

  Assuming that the bit accuracy of the affine coefficients that can be handled by the host device 101 is N bits and the bit accuracy of the affine coefficients that can be handled by the rendering device 103 is M bits, the pixel misalignment control unit 404 detects the pixel misalignment detection unit 406 when N> M is satisfied. Pixel shift detection. The comparison image creation unit 405 creates two images for comparison by changing the affine matrix and executing the pre-rendering process twice (in each pre-rendering process, the bit precision of the affine coefficients is different). That is, the comparison image generation unit 405 generates a first pre-rendering image based on pre-rendering processing using affine coefficients with N-bit accuracy, and a second pre-rendered image based on pre-rendering processing using affine coefficients using M-bit accuracy Create

  Next, the pixel misalignment detection unit 406 compares pixel values of each pixel of the first pre-rendered image and the second pre-rendered image, and checks whether the pixel values match. As a result, it is determined whether the first pre-rendered image and the second pre-rendered image are the same, in other words, whether or not there is a pixel shift between the first pre-rendered image and the second pre-rendered image.

<Reduction of Bit Accuracy of Affine Coefficient>
The bit precision of the affine coefficients that can be processed by the ASIC 306 mounted on the rendering device 103 is limited, and only affine coefficients less than M bit precision can be handled. Therefore, when the condition of N> M is satisfied between the bit precision (N bits) of the host apparatus 101 and the bit precision (M bits) of the rendering apparatus, the lower bits of the affine coefficient are cut off and the bit precision is N Need to reduce from bit precision to M bit precision.

  Hereinafter, the reduction of the bit precision of the affine coefficient will be described with reference to FIG. FIG. 7 is a diagram showing reduction in bit precision of affine coefficients. Column 701 represents affine coefficients a, b, c, d. A column 702 represents each value of affine coefficients with N-bit precision that can be handled by the host device 101, and a column 703 represents each value of affine coefficients with M-bit precision that can be handled with the rendering device 103 (ASIC 306). As for the affine coefficient a shown in line 704, the value that can be handled as 3.89068988998 in the host device 101 can be rounded down to 3.89068988 because the rendering device 103 can handle only those with M bit precision (N> M). It is done. The same applies to the affine coefficient d shown in the row 707, and the value that can be handled as 1.234323728501 in the host apparatus 101 is rounded down to 1.23432372. On the other hand, with regard to the affine coefficient b shown in the row 705 and the affine coefficient c shown in the row 706, since the original value was 0.0, the value after rounding down is also 0.0.

<About comparison of two pre-rendered images created by pre-rendering process>
FIG. 8 shows the result of pre-rendering processing using affine coefficients with N-bit precision and the result of pre-rendering processing using affine coefficients with M-bit precision. As illustrated, as a result of performing pre-rendering processing using affine coefficients with N-bit accuracy based on the original image 801 with a black frame on a white background, a first pre-rendered image 802 is created. Also, as a result of performing pre-rendering processing using affine coefficients with M-bit accuracy based on the original image 801, a second pre-rendered image 803 is created. The first pre-rendered image 802 and the second pre-rendered image 803 created are stored in the pre-rendered image storage unit 408. The pixel shift detection unit 406 compares the pixel values of these two pre-rendered images to determine whether there is a pixel shift between the two pre-rendered images, in other words, is the two pre-rendered images the same? judge.

  FIG. 9 is a diagram showing how the pixel values in the pre-rendered image are compared. Here, each of the pre-rendered images A, B, C, and D is a rectangular image consisting of 60 pixels having a height of 10 pixels and a width of 6 pixels, and the pixel shift detection unit 406 compares pixel values for each pixel. Show the case. For example, when a pixel value is expressed by three elements (R (red), G (green), B (blue)), it is checked whether all three element values of R, G, B match for each pixel. Ru. Then, when all the three element values match, it is determined that the pixel values match. The representation format of pixel values is not necessarily limited to the RGB format.

In this way, a total of 60 individual pixels are checked to see if their pixel values match. If the pixel values match for all pixels, no pixel shift occurs and if the pixel values do not match for at least one or more pixels, It is determined that a pixel shift occurs. The determination result is returned to the pixel shift control unit 404. FIG. 9A shows a case where it is determined that no pixel deviation occurs between the pre-rendered image A and the pre-rendered image B because the pixel values match for all 60 pixels in the image. On the other hand, in FIG. 9B, pixel deviation occurs between the pre-rendered image C and the pre-rendered image D because the pixel values of some pixels in the image (for example, the pixel 901 indicated by the white broken line) are different. In the case shown in FIG.
<About conversion of image object data>
The image object data conversion unit 407 converts the image object data when it is determined by the pixel displacement detection unit 406 that pixel displacement occurs. Image object data is composed of an original image and an affine matrix composed of a plurality of affine coefficients.

  As described above, in the rendering process using the affine coefficients with M-bit precision that can be handled by the rendering apparatus 103, there is a possibility that pixel shift may occur. Therefore, in the present embodiment, when pixel misalignment occurs, the image device data is corrected in advance so that pixel misalignment does not occur on the host apparatus 101 side. Specifically, the image resulting from the pre-rendering process using N-bit precision affine coefficients is treated as an original image, and the affine matrix is changed to output the original image at equal magnification.

  FIG. 10 is an explanatory diagram of conversion of image object data, and shows image object data before and after conversion. FIG. 10A shows image object data before conversion, and is composed of an original image 1001 and an affine matrix 1002 composed of affine coefficients a, b, c, d. The renderer applies an affine matrix to the original image to create a raster image which is an image resulting from the rendering process.

  On the other hand, FIG. 10 (b) shows image object data after conversion. By conversion of the image object data, the original image 1001 constituting the image object data before conversion is replaced with the image 1003 as a result of pre-rendering the original image 1001 using an affine matrix consisting of affine coefficients with N-bit precision. . In addition, the affine matrix 1002 that configures the image object data before conversion is also replaced with an affine matrix 1004 composed of affine coefficients 1, 0, 0, and 1. By the conversion of the image object data, the hardware renderer of the rendering device 103 executes the rendering process to output the image as a result of the pre-rendering process at the same magnification.

  The converted image object data derived by the image object data conversion unit 407 is transferred to the intermediate data generation unit 403 through the pixel shift control unit 404. Then, contents corresponding to the image object data after this conversion are described in intermediate data.

  The pre-rendering image storage unit 408 stores a pre-rendering image created as a result of the pre-rendering process by the comparison image creating unit 405 for detecting a pixel shift. The pixel shift detection unit 406 executes pixel shift detection processing to determine whether pixel shift occurs using the pre-rendered image stored in the pre-rendered image storage unit 408.

<Functional Configuration of Rendering Device>
Hereinafter, the functional configuration of the rendering device 103 will be described with reference to FIG.

  As described above, the CPU 302 executes the program loaded into the RAM 303. Here, a case where the program 504 is executed is shown. Thus, the rendering processing unit 502 is realized. The rendering device 103 further includes an intermediate data storage unit 501 and a raster image storage unit 503. The intermediate data storage unit 501 stores intermediate data created by the host device 101 and transmitted to the rendering device 103. The information related to the image object described in the intermediate data has a format suitable for the processing in the rendering processing unit 502 by the above-described processing in the host device 101. Note that this format differs depending on the rendering processing unit. The rendering processing unit 502 creates a raster image by performing rendering processing on intermediate data stored in the intermediate data storage unit 501. The raster image created by the rendering processing unit 502 is stored in the raster image storage unit 503. In the present embodiment, the ASIC 306, which is a hardware renderer, takes charge of processing in the rendering processing unit 502. However, a software renderer may take charge of processing.

<Intermediate data creation processing with pixel shift detection processing>
Hereinafter, intermediate data creation processing accompanied by pixel shift detection processing in this embodiment will be described using FIGS. 11 and 12. FIG. FIG. 11 is a flowchart of intermediate data creation processing in the present embodiment.

  In the intermediate data creation process, in step S1101, the PDL data interpretation unit 402 executes an analysis process on PDL data included in the print data. Specifically, the PDL data interpretation unit 402 focuses on one of the unprocessed rendering objects included in the PDL data, analyzes the rendering object of interest (referred to as a rendering object of interest), and analyzes the analysis result It is output to the data creation unit 403.

  In step S1102, the intermediate data generation unit 403 determines whether the focused drawing object is an image object based on the analysis result passed from the PDL data interpretation unit 402, specifically, the attribute information of the focused drawing object. If the determination result in step S1102 is true, that is, if the attribute information indicates that the target drawing object is an image object, the process advances to step S1103. On the other hand, if the determination result is false, that is, if the attribute information indicates that the target drawing object is an object other than the image object (for example, a fill object or a line object), the process advances to step S1108.

  Hereinafter, the case where the focused drawing object is determined to be an image object (in the case of YES in step S1102) will be described. In this case, in step S 1103, the pixel misalignment control unit 404 receives the image object data of the drawing object of interest and the information on the bit accuracy of the affine coefficients that can be handled (processed) by the rendering device 103 And get.

  In step S1104, the pixel misalignment control unit 404 determines whether the magnitude relationship of N> M is satisfied for the bit precision N that can be processed by the host apparatus 101 and the bit precision M that can be processed by the rendering apparatus 103. If the determination result in step S1104 is true, the process proceeds to step S1105, while if the determination result is false, the process proceeds to step S1107.

  In step S1105, the comparison image generation unit 405 and the pixel shift detection unit 406 cause the comparison image generation unit 405 and the pixel shift detection unit 406 to execute pixel shift detection processing to determine whether incorrect drawing, that is, whether pixel shift occurs. Do. If the determination result in step S1105 is true, the process proceeds to step S1106, while if the determination result is false, the process proceeds to step S1107. The details of the pixel shift detection process will be described later with reference to FIG.

  In step S1106, the pixel shift control unit 404 causes the image object data conversion unit 407 to convert image object data composed of an original image and an affine matrix as illustrated in FIG. 10 (image object data conversion processing). )).

  In step S1107, the intermediate data generation unit 403 generates intermediate data based on the image object data. At this time, when the image object data conversion process in step S1106 is executed, contents corresponding to the image object data after conversion are described in intermediate data. On the other hand, when the image object data conversion process is not executed (NO in step S1104 or NO in step S1105), contents corresponding to the image object data before conversion are described in the intermediate data.

  Subsequently, a case where it is determined that the focused drawing object is not an image object (in the case of NO at step S1102) will be described. In this case, in step S1108, the intermediate data generation unit 403 generates intermediate data by describing the information of the drawing object of interest in the intermediate data.

  After the information of the drawing object of interest is described in the intermediate data in step S1107 or step S1108, in step S1109, the PDL data interpretation unit 402 determines whether or not there is an unprocessed drawing object in the PDL data. When the determination result in step S1109 is true, the process returns to step S1101. On the other hand, when the determination result is false, a series of processing ends. The above is the contents of the intermediate data creation process in the present embodiment.

  Subsequently, the above-described pixel shift detection processing (step S1105 in FIG. 11) will be described in detail with reference to FIG.

  In step S <b> 1201, the comparison image generation unit 405 executes pre-rendering processing using the image object data transferred from the pixel shift control unit 404. Specifically, the first pre-rendered image is created by applying an affine matrix composed of affine coefficients with N-bit precision that can be processed by the host device 101 to the original image.

  In step S 1202, the comparison image generation unit 405 cuts off the lower bits of the affine coefficient with N-bit accuracy according to the information of the bit accuracy of the affine coefficient that can be handled by the rendering device 103 passed from the pixel shift control unit 404. This derives an affine matrix consisting of affine coefficients with M bit precision.

  In step S1203, the comparison image creation unit 405 creates a second pre-rendered image by executing a pre-rendering process of applying the affine matrix derived in step S1202 to the original image. The first pre-rendered image and the second pre-rendered image created by the comparative image creating unit 405 are stored in the pre-rendered image storage unit 408.

  In step S 1204, the pixel misalignment detection unit 406 focuses on one pixel which has not been compared among the pixels constituting the first pre-rendered image (setting of a target pixel). Similarly, the pixel shift detection unit 406 focuses on one pixel which has not been compared among the pixels constituting the second pre-rendered image. The coordinates of the target pixel of the first pre-rendered image and the target pixel of the second pre-rendered image, which are set in this step, are the same.

  In step S1205, the pixel shift detection unit 406 compares the pixel of interest of the first pre-rendered image with the pixel of interest of the second pre-rendered image, and determines whether these pixel values match. If the determination result in step S1205 is true, the process proceeds to step S1206, while if the determination result is false, the process proceeds to step S1208.

  In step S1206, the pixel shift detection unit 406 determines whether there is a pixel not compared yet. If the determination result in step S1206 is true, the process returns to step S1204. On the other hand, if the determination result is false, the process proceeds to step S1207.

  In step S1207, the pixel shift detection unit 406 returns the determination result YES to the pixel shift control unit 404.

  If these pixel values do not match for the target pixel of the first pre-rendered image and the second pre-rendered image (in the case of NO in step S1205), in step S1208, the pixel displacement detection unit 406 It returns to the deviation control unit 404. The above is the contents of the pixel shift detection processing in the present embodiment.

Example 2
In the first embodiment, in order to detect that no pixel shift occurs, it is necessary to compare pixel values for all pixels of the pre-rendered image. Therefore, when the number of pixels constituting the pre-rendered image is large, the processing time is long. Therefore, in the present embodiment, the processing speed can be increased by reducing the number of pixels to be compared. In the following, differences from the above-described embodiment will be mainly described, and the description of the same contents as the above-described embodiment will be appropriately omitted.

  FIG. 13 shows a state in which pre-rendering processing is performed on an original image 1301 in which two black lines are drawn on a white background using different affine matrices. The pre-rendered image 1302 shows an image resulting from the pre-rendering process using an affine matrix in which the affine coefficients b and c are zero. Further, a pre-rendered image 1303 indicates an image obtained when the pre-rendering process is performed using an affine matrix in which the affine coefficients a and d are zero. Here, the pre-rendering image 1302 is an image obtained as a result of pre-rendering processing of rotating the original image by 0 degrees or 180 degrees, and the pre-rendering image 1303 is a result of pre-rendering processing of rotating the original image by 90 degrees or 270 degrees. It is an image obtained. The feature of this embodiment is to compare only the pixels of the outermost frame of the pre-rendered image when the angle of rotation by the pre-rendering process is 0 degree, 90 degrees, 180 degrees, or 270 degrees. The reason for doing this is that if a pixel shift occurs when the rotation angle in the pre-rendering process is 0 degrees, 90 degrees, 180 degrees, or 270 degrees, the pixels in any of the pixels in the outermost frame of the pre-rendered image must Since a shift appears, it is sufficient to compare only the pixels in the outermost frame.

  FIG. 14 is a diagram for explaining pixels to be compared in the pixel shift detection process in the present embodiment. Reference numeral 1401 in the figure denotes a pre-rendered image. The pre-rendered image 1401 mentioned here is a rectangular image consisting of 60 pixels of height 10 pixels and width 6 pixels.

  Reference numeral 1402 indicates the pixel to be compared in the pre-rendered image 1401 in the case where all the pixels as described in the first embodiment are to be compared, and the pixel to be compared is represented by gray. On the other hand, reference numeral 1403 indicates the pixels to be compared in the pre-rendered image 1401 in the case of this embodiment, that is, in the case where only the pixels in the outermost frame are to be compared. It represents. As indicated by reference numerals 1402 and 1403, in these cases, the number of pixels to be compared when all pixels are to be compared is 60, and the number of pixels to be compared when only the outermost frame pixels is to be compared is 28. Because of this, the number of pixels to be compared is reduced by 50% or more.

  FIG. 15 is a flowchart of pixel shift detection processing in the present embodiment. The pixel shift detection process in the present embodiment is basically the same as that in the first embodiment. Describing in detail, step S1501 to step S1503 and step S1505 to step S1508 are the same as step S1201 to step S1203 and step S1205 to step S1208 of the first embodiment (see FIG. 12).

  However, step S1504 is different from step S1204 of the first embodiment. In step S1504, the pixel shift detection unit 406 focuses on one pixel not compared yet, but in the present embodiment, it focuses on the outermost frame of the pre-rendered image in order at this focus. In the first embodiment, as described above, the present embodiment differs from the first embodiment in this respect, since all the pixels of the pre-rendered image are focused in order.

  According to this embodiment, it is possible to finish the pixel shift detection process in a short time.

[Example 3]
In the embodiment described above, the pixel shift detection process is performed on the image object whenever the relationship of N> M is satisfied. However, among the image objects, there are objects which are difficult for the user to notice even if a pixel shift occurs. For example, when the original image is composed of only black and white two color pixels, when the black pixel is shifted, the user can easily notice the pixel shift, while when the original image is composed of pixels of various colors, It is very difficult for the user to notice the pixel shift as far as the pixel shifts. Therefore, in the present embodiment, when the number of colors in the original image is large, the pixel shift detection process is skipped. In the following, differences from the above-described embodiment will be mainly described, and the description of the same contents as the above-described embodiment will be appropriately omitted.

  FIG. 16 is a block diagram showing a functional configuration of the host apparatus 101 in the present embodiment. The host device 101 in the present embodiment further includes an original image determination unit 1609 in addition to the configuration (see FIG. 4) shown in the first embodiment. The original image determination unit 1609 determines whether the number of colors in the original image exceeds a predetermined threshold L. Then, in accordance with the determination result, the pixel shift control unit 1604 controls whether to execute the pixel shift detection process.

  FIG. 17 is a flowchart of pixel shift detection processing in the present embodiment. The pixel shift detection process in this embodiment is basically the same as that in the first embodiment (see FIG. 11), but it is determined whether the total number of colors included in the original image is larger than a predetermined threshold ( This embodiment differs from the first embodiment in that step S1704) is further included. The details of the original image determination process will be described later with reference to FIG. As shown in FIG. 17, when the total number of colors included in the original image is larger than a predetermined threshold value, pixel shift detection processing is not executed (YES in step S1704 → step S1708).

<About original image judgment processing>
Hereinafter, an original image determination process (step S1704 in FIG. 17) of determining whether the total number of colors included in the original image is larger than a predetermined threshold will be described with reference to FIG.

  In step S1801, the original image determination unit 1609 focuses on one unprocessed pixel among the pixels constituting the original image (setting of a target pixel).

  In step S1802, the original image determination unit 1609 derives the color of the pixel of interest, and stores the derived color information (for example, a combination of RGB values in the case of the RGB format).

  In step S1803, the original image determination unit 1609 determines whether the derivation of the colors of all the pixels of the original image has ended. If the determination result in step S1803 is true, the process proceeds to step S1804. If the determination result is false, the process returns to step S1801.

  In step S 1804, the original image determination unit 1609 derives the total number of colors included in the original image using the color information (for example, in the case of RGB format, RGB values of each pixel) derived in steps S 1801 to 1803. Do.

  In step S1805, the original image determination unit 1609 determines whether the total number of colors included in the original image derived in step S1804 exceeds a predetermined threshold (L). If the determination result in step S1805 is true, the process proceeds to step S1806, while if the determination result is false, the process proceeds to step S1807.

  If the total number of colors included in the original image is larger than the predetermined threshold, the original image determination unit 1609 returns a determination result YES to the pixel shift control unit 404 in step S1806.

  If the total number of colors included in the original image is less than or equal to the predetermined threshold value, the original image determination unit 1609 returns the determination result NO to the pixel shift control unit 404 in step S1807. The above is the contents of the original image determination processing in the present embodiment.

  According to this embodiment, by performing control so as not to execute pixel shift detection processing on an image object having a large number of colors of the original image, pixel shift detection processing can be completed at high speed. The present embodiment may be combined with the second embodiment.

[Other embodiments]
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. Can also be realized. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

101 Host Device 103 Rendering Device 403 Intermediate Data Creation Unit 406 Pixel Deviation Detection Unit 407 Image Object Data Conversion Unit

Claims (12)

A host device for creating intermediate data necessary for creating a raster image with a rendering device based on PDL data,
A detection means for detecting whether or not the image object data is illegally drawn based on the image object data contained in the PDL data, the bit accuracy processable by the host device, and the bit accuracy processable by the rendering device When,
Conversion means for converting the image object data when the detection means detects the occurrence of the incorrect drawing;
And a creating unit configured to create the intermediate data based on the converted image object data. The image processing apparatus further comprises interpretation means for interpreting the PDL data,
The host device according to claim 1, wherein the creation unit creates the intermediate data based on an analysis result by the interpretation unit.   If the bit accuracy that can be processed by the host device is larger than the bit accuracy that can be processed by the rendering device, the detection unit detects whether the incorrect drawing occurs, while the bit accuracy that can be processed by the host device is The host device according to claim 1 or 2, wherein the detection unit does not detect whether or not the incorrect drawing occurs if the bit accuracy is less than or equal to the bit accuracy that can be processed by the rendering device.   4. The image object data according to any one of claims 1 to 3, wherein the image object data comprises an original image and an affine matrix for determining how to scale, move, and rotate the original image. Host device described.   The conversion means converts the original image contained in the image object data into an image obtained by applying the affine matrix to the original image, and the affine matrix contained in the image object data is the image, etc. 5. The host device according to claim 4, wherein the host device is converted into a double output matrix. The detection means is
Creating means for creating a first image by applying, to the original image, an affine matrix composed of bit precision affine coefficients that can be processed by the host device;
Creating means for creating a second image by applying, to the original image, an affine matrix consisting of affine coefficients that can be processed by the rendering apparatus and having bit precision;
And determining means for determining whether the pixel values of the first image and the second image match.
When the determination means determines that the pixel values of the first image and the second image do not match, the detection means detects that the incorrect drawing occurs. The host device according to 4 or 5.   7. The host apparatus according to claim 6, wherein the determination unit determines whether the pixel values of the outermost pixels of the first image and the second image coincide with each other. It further comprises derivation means for deriving the total number of colors included in the original image,
If the total number of colors is greater than a predetermined threshold, the detection means does not detect whether the incorrect drawing occurs or not, if the total number of colors is less than or equal to the predetermined threshold, the detection means generates the incorrect drawing The host device according to any one of claims 4 to 7, wherein the host device is detected.   The host device according to any one of claims 1 to 8, wherein the rendering device has a hardware renderer that creates a raster image based on the intermediate data. A system comprising: a host device that creates intermediate data based on PDL data; and a rendering device that creates a raster image based on the created intermediate data,
The host device is
A detection means for detecting whether or not the image object data is illegally drawn based on the image object data contained in the PDL data, the bit accuracy processable by the host device, and the bit accuracy processable by the rendering device When,
Conversion means for converting the image object data when the detection means detects the occurrence of the incorrect drawing;
Creating means for creating the intermediate data based on the converted image object data;
The system according to claim 1, wherein the rendering device comprises a hardware renderer for creating a raster image based on the intermediate data. A method executed by a host device for creating intermediate data necessary for creating a raster image with a rendering device based on PDL data,
Detecting whether illegal drawing of the image object data occurs based on image object data included in the PDL data, bit accuracy that can be processed by the host device, and bit accuracy that can be processed by the rendering device; ,
Converting the image object data when the occurrence of the incorrect drawing is detected;
Creating the intermediate data based on the transformed image object data.   A program for making a computer execute the method according to claim 11.

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