JP2013008247A - Image processing apparatus, image processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that although detail improvement is achieved by generating and storing document image data in the form of a vector without rasterization limitedly to a rendering object such as a small character and a thin line and rendering the object at a magnification rate corresponding to print settings in a printing process, a gap is formed at a border between adjacent rendering objects when an object of high resolution and an object of low resolution are rendered to the different resolutions.SOLUTION: An image processing apparatus includes rendering object generation means of interpreting PDL data and generating the rendering object; generation means of generating rendering data by quantizing coordinate values of respective pixels included in the rendering object generated by the rendering object generation means with a predetermined resolution; and holding means of holding values discarded through the quantization as additional information on coordinate values when the coordinate values are quantized by the generation means with the determined resolution. The holding means holds the additional information in an area different from the coordinate values of the determined resolution, obtained through the quantization, of the rendering data generated by the generation means.

Description

  The present invention relates to an image processing apparatus connected to a network and having a function of processing document image data. In particular, the present invention relates to a function of receiving document image data and outputting an image.

  Conventionally, as a technique for performing high-resolution rendering processing at high speed, for example, there is a technique disclosed in Patent Document 1. Further, as a technique for reducing the cost of rendering processing by rendering only a specific portion in a page with high resolution, there is a technique disclosed in Patent Document 2. Further, as a generally known technique, a smoothing technique is widely used in which a pixel interpolation or edge shape pattern matching technique is applied to a low-resolution rendered image to increase the output resolution.

  By combining the above-described conventional techniques, it is possible to improve the apparent image quality while suppressing the processing cost of image generation.

JP 2000-137825 A JP 2009-274366 A JP 2010-171622 A

  By the way, a digital multi-function peripheral having a printer function can change a print setting set in document image data at the time of printing by using a box function capable of storing document image data. Among the print setting items of the digital multi-function peripheral, there are functions associated with image enlargement / reduction regarding the functions of aggregate printing, page size change, and resolution switching. In the box function of the conventional digital multi-function peripheral, there is a problem that when the image size and resolution set at the time of saving the document image data are changed at the time of print output, image quality deterioration occurs due to the image enlargement / reduction processing. . This is because the document image data stored in the box is a raster image that matches the image size and resolution at the time of storage. In order to reduce image quality degradation due to enlargement / reduction, smoothing technology is also applied, but when drawing objects saved as rasters are scaled, the line width varies depending on the position in the image. May be.

  For example, in Patent Document 3, the line width can be stabilized even when scaling is performed. However, even if the problem of the line width is improved, in the first place, in the case of image data including fine drawing, the detail after scaling and smoothing is unavoidable. Has the disadvantage of being lost.

  Create and store document image data as vector information without rendering it into raster objects only for drawing objects for which details are to be saved, such as small character and thin line drawing objects, and render at the magnification according to the print settings when printing, Detail improvement is possible. However, when the document image data includes both a high-resolution object and a low-resolution object, a plurality of drawing objects are rendered at different resolutions as shown in FIG. There may be gaps.

  In FIG. 10, the left side is an arrangement example in the representation of real coordinate values of the drawing object before rendering. The pixel boundary position at the resolution when these objects are rendered is represented by being superimposed as a grid. The right side represents a pixel on which the drawing object is quantized and painted with a specific resolution by rendering. As shown on the right side, when an object expressed in dark gray and an object expressed in light gray are rendered at the same resolution and quantized, as shown in the top and second of FIG. There is no gap between each object. On the other hand, in the lowermost figure, a lowercase drawing object expressed in dark gray is quantized with a resolution of 1200 dpi, and a pixel to be painted is determined. A graphics drawing object expressed in light gray is quantized with a resolution of 600 dpi, and a pixel to be painted is determined. In the case of the object arrangement as shown in this example, since the position in the real space quantized at each resolution is different, a pixel that is not painted between two different objects may occur.

  The present invention solves the above problem by improving the coordinate accuracy of low resolution objects stored rasterized in document image data.

  In order to solve the above problems, an image processing apparatus according to the present invention has the following configuration. That is, an image processing apparatus that generates drawing data from PDL data described in an input page description language, the drawing object generating unit interpreting the PDL data and generating a drawing object, and the drawing object generating unit When the coordinate value of each pixel included in the drawing object generated by the above is quantized with a predetermined resolution to generate drawing data, and when the coordinate value is quantized with the predetermined resolution by the generating unit And holding means for holding a value to be truncated by quantization as additional information of coordinate values, and the holding means obtains the additional information by quantization of the drawing data generated by the generating means. It is held in an area different from the coordinate value at the determined resolution.

  According to the present invention, by adding additional information for correcting the coordinate accuracy to the drawing data of the low-resolution drawing object stored rasterized in the document image data, the low-resolution object is Quality improvement in drawing becomes possible.

1 is a diagram illustrating an example of the overall configuration of a printing environment including a digital multifunction peripheral. FIG. 2 is a block diagram illustrating an internal configuration of a control device of the digital multifunction peripheral. The figure which shows the example of the flow of a production | generation of document image data. The figure which shows the data structure of document image data. The figure which modeled the processing content of the document image data generation program. The figure which modeled another processing content of the document image data generation program. The flowchart which shows the process of the program which renders document image data. The flowchart which shows the rendering process using only edge coordinate information. The flowchart which shows the rendering process using edge coordinate information and additional information. The figure for demonstrating a subject. The figure which shows the relationship between the parameter used when determining image magnification, and image magnification.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The configuration of the system shown below is an example, and the present invention is not limited to this.

<First embodiment>
[System configuration]
The overall configuration of the digital multifunction peripheral according to this embodiment will be described with reference to FIG. The digital multifunction peripheral 403 according to the present embodiment includes a control device 100, an operation unit 150, a reader unit 200, and a printer unit 300. Further, it is connected to the PCs 401 and 402 via the LAN 400. A reader unit (image input device) 200 optically reads a document image and converts it into image data. The reader unit 200 includes a scanner unit 210 having a function for reading a document and a document feeding unit 250 having a function for transporting a document sheet.

  A printer unit (image output device) 300 conveys recording paper, prints image data as a visible image thereon, and discharges the recording paper out of the device. The printer unit 300 has a paper feed unit 310 having a plurality of types of recording paper cassettes, a marking unit 320 having a function of transferring and fixing image data to the recording paper, and a function of outputting the printed recording paper to the outside of the apparatus. And a paper discharge unit 330.

  The control device 100 is electrically connected to the reader unit 200 and the printer unit 300, and further connected to PCs 401 and 402 and various servers on the Internet via the LAN 400. The control device 100 controls the reader unit 200 to read the image data of the original, and controls the printer unit 300 to output the image data to a recording sheet to provide a copy function. In addition, the control device 100 provides a scanner function that converts image data read by the reader unit 200 into code data and transmits the code data to a PC or the like via the LAN 400. In addition, the control device 100 provides a printer function that converts print job data including PDL (Page Description Language) data received from a PC or the like via the LAN 400 into image data and outputs the image data to the printer unit 300.

  Furthermore, the control device 100 generates document image data from print job data including image data read from the reader unit 200 and PDL data received from a PC or the like. Then, the control device 100 stores the box image storing function for storing the document image data in the secondary storage device in the control device 100, and the document image data stored in the secondary storage device in the control device 100 with the box storage function. Is provided, and a box printing function is provided for outputting to the printer unit 300.

  The operation unit 150 is connected to the control device 100, is configured with a liquid crystal touch panel or the like, and provides a user I / F for operating the image input / output system. The PCs 401 and 402 generate print job data including PDL data, and transmit the print job data to the control apparatus 100 via the LAN 400.

  FIG. 2 is a block diagram showing an example of the configuration of the control apparatus for the digital multifunction peripheral according to the present embodiment. In FIG. 2, a control device 100 is connected to a reader unit 200 that is an image input device and a printer unit 300 that is an image output device, and performs control for reading image data and printing output. In addition, the control device 100 performs control for inputting / outputting print job data including PDL data and device information via the LAN 400 by connecting to the LAN 400.

  Further, the control device 100 develops print job data including PDL data received via the LAN 400 or document image data stored in the HDD 104 as a built-in storage device (storage unit) into an image that can be printed out. . Further, the control device 100 converts the format of print job data including PDL data received via the LAN 400 and stores the generated document image data in the HDD 104 which is a storage device.

  The CPU 101 is a central processing unit for controlling the entire digital multifunction peripheral 403. A RAM 102 is a system work memory for the CPU 101 to operate, and is also a memory for temporarily storing print job data including input PDL data, document image data being converted, and various attributes at the time of printing. A ROM 103 is a boot ROM and stores a system boot program. An HDD 104 is a hard disk drive that stores system software for various processes, converted document image data, and the like.

  The operation unit I / F 105 is an interface unit for the operation unit 150, and outputs operation screen data to the operation unit 150. The operation unit I / F 105 serves to transmit information input by the operator from the operation unit 150 to the CPU 101. The network interface 107 is realized by a LAN card or the like, for example, and is connected to the LAN 400 to input / output information to / from an external device. The above units are arranged on the system bus 106.

  An image bus I / F 109 is an interface for connecting the system bus 106 and an image bus 110 that transfers image data at high speed, and is a bus bridge that converts a data structure. A device I / F 111 and a printer image processing unit 112 are connected on the image bus 110.

  The device I / F 111 connects the reader unit 200 or the printer unit 300 to the control device 100 and performs synchronous / asynchronous conversion of image data. The printer image processing unit 112 performs image processing such as correction according to the printer unit 300 on the image data to be printed out.

[User Box Save Function]
Next, a box storage function program and a box printing function program that operate in the control device 100 of the digital multi-function peripheral 403 will be described with reference to FIG. First, the configuration of a box storage function program that generates document image data as drawing data from PDL data in print job data and stores it in the HDD 104 will be described with reference to FIG. At the same time, the document image data generation procedure by the box storage function program will be described.

  The PDL data 3001 is stored in the RAM 102 or the HDD 104 and is read by the PDL interpretation unit 3002. Here, in the PDL data 3001, a page description language such as LIPS (registered trademark) LX or UFR II is used. Further, the plane coordinate system defined by the PDL data 3001 is hereinafter referred to as “src coordinate system”. The PDL interpretation unit 3002 interprets the PDL data 3001. Further, the drawing object generation unit 3003 generates a plurality of drawing objects suitable for printing from the interpreted PDL data 3001 in the order suitable for printing.

  The drawing objects included in one page are arranged in consideration of drawing overlap. The drawing objects that are covered by the overlap are arranged in the drawing order first, and the drawing objects that are drawn over the at least part of the above-described objects are arranged later.

  Each drawing object has one of five types of object attributes, Text, Small_text, Graphics, thin_Line, and Image. A drawing object having a Text attribute holds outline font vector data or bitmap font bitmap data. A drawing object having a Small_text attribute is a drawing object having a particularly small character size among drawing objects holding font data. Here, it is assumed that the character has a size smaller than a predetermined size. A drawing object having a Graphics attribute holds path data described in a vector format. A drawing object having a thin_Line attribute is a drawing object having a particularly small line width among drawing objects that hold path data. Here, it is assumed that a line having a line width equal to or smaller than a predetermined value has. A drawing object having an Image attribute holds uncompressed bitmap image data or compressed image data.

  The lowercase thin line object separation unit 3004 receives the drawing object from the drawing object generation unit 3003 and determines the object attribute. When the object attribute is “Small_text” or “thin_Line”, the drawing object is passed to the document image data generation unit 3007 without being changed. When the object attribute is any one of “Text”, “Graphics”, and “Image”, the drawing object is passed to the edge data generation unit with coordinate hint 3005.

  The coordinate hint-attached edge data generation unit 3005 converts each object of the Text, Graphics, and Image attributes into a data structure called edge data, and passes it to the document image data generation unit 3007. The edge data will be described later with reference to FIGS. Here, the coordinate hint-added edge data generation unit 3005 spools the data as edge data (edge data spool 3006), and passes the document image data generation unit 3007 when the processing on the document image data is completed.

  The document image data generation unit 3007 sequentially receives drawing objects from the lowercase thin line object separation unit 3004 or the edge data generation unit with coordinate hints 3005 and converts them into a predetermined document image data format. The file spooler 3008 temporarily accumulates document image data that is converted and output as needed by the document image data generation unit 3007 and stores it as document image data 3009. When the document image data generation unit 3007 completes the conversion processing for all drawing objects, the generated document image data 3009 is transferred to the HDD 104 that is a file storage destination of the box storage function.

  Next, the configuration of the box printing function program that converts the document image data 3009 stored in the HDD 104 into a print output image and outputs it from the printer unit 300 will be described. At the same time, a procedure for the box print function program to convert the document image data 3009 into a print output image will be described. A coordinate system plane defined on an image drawn by the printer unit 300 will be referred to as a “device coordinate system”.

  First, when the user operates the box printing function with the operation unit 150, the box printing function program starts operation. The box printing function program transfers document image data 3009 stored in the HDD 104 and instructed to be printed by the user to the instruction processing unit 3010 according to a user operation. The instruction processing unit 3010 reads an instruction (described later) in the document image data 3009 and performs a process determined for each type of instruction.

  The coordinate hint-attached edge data developing unit 3011 develops the edge-attached edge data in the document image data 3009 and generates edge data expressed in the device coordinate system. Here, the “edge data with hint” is data generated by the edge data generation unit 3005 with coordinate hint. That is, a drawing object having any attribute of “Text”, “Graphics”, and “Image” is a target.

  The vector object edge generation unit 3012 processes the vector data separated by the lowercase thin line object separation unit 3004 and embedded in the document image data 3009. That is, the data handled here is a drawing object having any attribute of “Small_text” and “thin_Line”. At this time, the vector data is subjected to scan line conversion, and edge data including the coordinate value of the intersection of the vector path and the scan line on the device coordinate system plane is generated.

  The edge data in the device coordinate system generated by the edge data development unit 3011 with coordinate hints and the vector object edge generation unit 3012 is output by the level processing unit 3013 using the level information of the edge data. Is determined. The level information here will be described later. Thereafter, all edge data for which the level overlap state is determined is passed to the Pixel generation unit 3014, and Pixels having color values determined by Fill (described later) specified for each level in the edge data are generated. The The generated Pixel is stored in the page spool 3016 secured in the HDD 104 by the page image spooler 3015, and is transferred to the printer unit 300 and printed when an image for one page is generated.

[data structure]
Next, the internal data structure of the document image data file used in the box saving function and the box printing function according to this embodiment and the role of each data will be described with reference to FIG.

  The document image data 3009 according to this embodiment includes information necessary for rendering an area corresponding to one page. Instructions 4001 to 4008 in FIG. 4 are instructions for instructing the start of processing at each stage of the rendering process. Each instruction has additional information as necessary. The program according to the present embodiment generates an image by sequentially processing instructions in document image data.

  The instruction 4001 is <START_PAGE> and has an address 4002 (PageInfoAddress) to the PageInfo 4100 in which various setting values that can be used at the time of printing are recorded as additional information. When reading <START_PAGE>, the instruction processing unit 3010 illustrated in FIG. 3 performs various preparations for generating a print image. The instruction processing unit 3010 compares the setting values in the page size, layout information, and resolution data with the setting values specified by the user in the operation unit 150. Calculate the magnification.

  The instruction 4003 is <LOAD_HINTED_EDGE>, and includes three addresses of Scanline edge list address (EdgeListAddress), hint information address (HintAddress), and fill table address (LevelAddress) as additional information 4004. Further, the additional information 4004 also describes an image area flag (Text, Graphics, or Image) and a y-coordinate value on the src coordinate system. When the instruction processing unit 3010 reads <LOAD_HINTED_EDGE>, the instruction processing unit 3010 transfers the additional information 4004 to the edge data developing unit 3011 with coordinate hints. Thereafter, the edge data developing unit 3011 with coordinate hints generates edge data expressed in the device coordinate system.

  The instruction 4005 is <LOAD_VECTOR_SEG>, and has two addresses, a vector segment address (VectSegAddress) and a fill table address (LevelAddress), as additional information 4006. Furthermore, the instruction 4005 has additional information including an image area flag (Small_text or thin_Line). When reading <LOAD_VECTOR_SEG>, the instruction processing unit 3010 transfers additional information 4006 to the vector object edge generation unit 3012. Thereafter, the vector object edge generation unit 3012 generates edge data expressed in the device coordinate system.

  Instruction 4007 is <RENDER_EDGES> and there is no additional information. When reading <RENDER_EDGES>, the instruction processing unit 3010 determines that the edge information expressed in all the device coordinate systems in the page is complete. The box printing function program starts processing of the level processing unit 3013, the pixel generation unit 3014, and the page image spooler 3015.

  Instruction 4008 is <END_PAGE> and there is no additional information. When the instruction processing unit 3010 reads <END_PAGE>, the instruction processing unit 3010 determines that all image generation processing for one page has been completed. Thereafter, the box printing function program transfers the generated image held in the page spool 3016 to the printer unit 300.

  The PageInfo 4100 records information related to page size, aggregated layout information, data resolution, paper information, and post-processing described in the PDL data 3001.

  The edge data 4200 stores information of integer value edges (described later) at the scanline intersection generated by the coordinate hint-added edge data generation unit 3005.

  The coordinate hint information 4300 stores ¼ coordinate hint information 4300 for the above-mentioned Scanline edge and edge data 4301, 4302, and 4303 related to the Sub-Scanline edge. The coordinate hint information 4300 and the edge data 4301 to 4303 are used for correcting the edge coordinates. Details will be described later.

  In the level information 4400 referred to in the instructions 4003 and 4005, “level” is a concept indicating an overlap of drawn objects, and a drawing object having a large level value covers a drawing object having a small level value. hide. That is, a drawing object with a high level is overlaid in the drawing order. Therefore, when a plurality of drawing objects are overlapped on the same coordinate, only the drawing object having the largest level value is rendered. One level holds a number indicating a level value and address information in which a Fill corresponding to the level is stored. “Fill” is information necessary for determining the color value of the pixel, and is stored in the Fill table 4500.

  The vector segment 4600 holds coordinate information of a vector path to be processed by the vector object edge generation unit 3012. The vector path is expressed by a set of a plurality of continuous line segments, and is represented by an absolute coordinate value (x, y) indicating the vector path start point and a relative coordinate value (Dx, Dy) indicating the end point of the line segment starting from the start point. is there. Further, the subsequent line segment is also expressed as a relative coordinate value.

  The raster image data 4700 indicates its position in the memory by describing its address as one form of information in the Fill table. Raster image data 4700 that has been appropriately converted for enlargement / reduction is used as a color value for a region rendered in Image.

[Process description]
Next, the processing in the edge data generation unit with coordinate hints 3005 in the box storage function program that operates in the control device 100 of the digital multi-function peripheral 403 will be described in detail with reference to FIG. In this process, the edge data generation unit with coordinate hint 3005 calculates the coordinates of the pixels included in the drawing object by quantizing the drawing object to a predetermined resolution. Further, the coordinate hint-attached edge data generation unit 3005 calculates and holds coordinate values to be cut off at predetermined intervals by quantization. In the present embodiment, the predetermined interval with respect to the coordinate value to be discarded is set to an interval of 1/4 with respect to the coordinate value obtained by quantization. Therefore, in this processing, coordinates obtained by quantization are described as integer coordinate values, and coordinates including values to be rounded down are described as real number coordinate values.

  A grid indicated by a thick solid line on the left side of FIG. 5 is a grid indicating integer coordinate values on the src coordinate system plane defined by the PDL data 3001. In addition, the grid indicated by the vertical thin dotted line and the horizontal thin dotted line is a real number of 1/4, 2/4, and 3/4, which is obtained by dividing the integer coordinate value into four equal parts on the src coordinate system plane. It is a grid showing coordinate values.

  The src coordinate system is defined by a planar coordinate system in which the upper left corner is the origin, the horizontal direction is x, and the vertical direction is y. The fact that the horizontal line is an arrow on the src coordinate system plane represents that the scan line conversion is performed using the y coordinate value indicated by the line. A thick solid line shown diagonally represents a path described in a vector format in a drawing object having a Graphics attribute. Further, the gray area adjacent to the left side of the path expresses a paint area associated with the path.

  The coordinate hint-attached edge data generation unit 3005 performs scan line conversion in a direction in which the y coordinate and the x coordinate increase. In this specification, a value obtained by rounding up the coordinate value of the intersection position of the scan line and the path calculated by the scan line conversion is defined as an “edge coordinate value”. The position indicated by the edge coordinate value is defined as “edge”.

  In this process, first, the edge data generation unit with coordinate hint 3005 performs scan line conversion with an integer y coordinate value. The edge coordinate value obtained as a result is referred to as “Scanline intersection point coordinate”. The x-coordinate value of the Scanline intersection coordinate is first rounded up to an integer and held as a 15-bit integer (corresponding to the icon Δ shown in FIG. 5). In the present embodiment, 1-bit information (IsEdge flag) is further added to the 15-bit value and held. The definition of the IsEdge flag will be described later.

  The edge data generation unit with coordinate hint 3005 also calculates an x-coordinate value rounded up to any of integer-3 / 4, integer-2 / 4, integer-1 / 4, or integer as a more accurate edge coordinate value. To do. Here, this value is referred to as “¼ hint coordinate value”. The 1/4 coordinate hint information (x) of the Scanline intersection coordinate is expressed by a 2-bit value as a coordinate value difference (difference coordinate) with respect to the integer x coordinate value. In the present embodiment, -3/4 is "11", -2/4 is "10", -1/4 is "01", and if there is no coordinate value difference, a 2-bit decimal value of "00" is applied and held. (Equivalent to the icon ◇ shown in FIG. 5).

  Next, the coordinate hint-attached edge data generation unit 3005 performs the scan line conversion with the real number y coordinate values of integer + 1/4, integer + 2/4, and integer + 3/4. The edge coordinate value obtained as a result is set as the Sub-Scanline intersection point coordinate. The Sub-Scanline intersection point coordinate value (x) is rounded up to a value obtained by adding a real value of ¼ unit to the integer value. The rounded-up coordinate value is expressed as a 3-bit value and a sign bit as a difference value (multiple of 1/4) with respect to the edge coordinate value (x) of the immediately preceding Scanline intersection, and is held as 5-bit data with a 1-bit IsEdge flag added. Is done. Since such a process is sequentially performed three times with each real number y coordinate value of integer + 1/4, integer + 2/4, and integer + 3/4, a total of 15 bits (5 bits × 3 lines) of data is generated and held ( This corresponds to the icon ● shown in FIG. The IsEdge flag indicates whether or not there is an edge on the scan line.

  By the way, the path of FIG. 5 (thick solid line shown diagonally) has no Scanline intersection and Sub-Scanline intersection in the range beyond the lower end (y> 23 + 2/4), so there is no edge. Even when there is no Sub-Scanline intersection, a data area for holding edge coordinate values is secured. Therefore, the edge data generation unit with coordinate hint 3005 sets “0” as the edge coordinate value and “0” in the IsEdge flag when there is no Sub-Scanline intersection.

  In the vicinity of the upper end of the path in FIG. 5 (y = 21 + 2/4), there is a Sub-Scanline intersection, but in a range beyond the upper end (y <21 + 2/4), there is no Scanline intersection and Sub-Scanline intersection. In such a case, the coordinate hint-attached edge data generation unit 3005 sets “imaginary edge” with an integer y coordinate value above the upper end of the edge. For this purpose, first, the edge data generation unit with coordinate hint 3005 starts from the integer y coordinate (y = 22) closest to the upper end of the path, and proceeds in the sub-scanline intersection point in the direction in which the y coordinate value decreases (upward). Perform scan line conversion to calculate edge coordinates from. When a Sub-Scanline intersection exists, the edge data generation unit with coordinate hint 3005 stores the calculated intersection coordinate value as a real value in a temporary area in the RAM 102, and further sets “1” as a value representing the IsEdge flag. "Is also held. Since there is no Sub-Scanline intersection in the range exceeding the upper end of the path (y <21 + 2/4), the edge data generation unit with coordinate hint 3005 only has a value “0” representing the IsEdge flag in a temporary area in the RAM 102. Hold.

  Next, the edge data generation unit with coordinate hint 3005 calculates a fictitious Scanline intersection at an integer y coordinate value. The edge data generation unit with coordinate hint 3005 calculates the Sub-Scanline intersection coordinate value (x) in the Sub-Scanline when the real y-coordinate value is small (y = 21 + 2/4) among the above-mentioned Sub-Scanline intersection values. Calculate with real values. The edge data generation unit with coordinate hint 3005 rounds this up from a real value to an integer (ceil), and sets a 15-bit integer as a fictitious edge coordinate value (x = 426). Further, the edge data generation unit with coordinate hint 3005 sets the IsEdge flag to “0” and holds it. This is the edge for the fictitious Scanline intersection at y = 21. The 1/4 coordinate hint information (2 bits) for this imaginary edge is set and held as “00”. In addition, the real coordinate value and the IsEdge flag related to the Sub-Scanline intersection point held in the temporary area in the RAM 102 in the processing so far are regenerated as a difference value (a multiple of 1/4) with respect to the edge coordinate of the fictitious Scanline intersection point. Calculated. A 3-bit value, a sign bit, and a 1-bit IsEdge flag are added and held. Since the Sub-Scanline intersection is recalculated with the real number y coordinate values of integer + 1/4, integer + 2/4, and integer + 3/4, data of a total of 15 bits is generated and held.

  Here, the correspondence between the data shown in FIGS. 4 and 5 is shown. The edge data 4200 in FIG. 4 corresponds to an integer (16 bits) of the scanline intersection coordinates in FIG. Also, the coordinate hint information 4300 in FIG. 4 corresponds to a 1/4 hint (2 bits) of the scanline intersection coordinate in FIG. Further, each of the edge data 4301 to 4303 in FIG. 4 corresponds to each value (5 bits) of the difference between the 1/4 coordinates of the Sub-Scanline intersection coordinates in FIG.

[Process when leveling the path]
By the way, in the processing by the coordinate hint-added edge data generation unit 3005 described with reference to FIG. 5, the difference between the Scanline coordinate value and the Sub-Scanline edge coordinate value becomes too large when the inclination of the path is almost horizontal. For this reason, this difference cannot be fully expressed with 3 bits, which is the number of bits defined in advance to express the difference. Processing in such a case will be described with reference to FIG.

  In FIG. 6, the path between y = 22 and y = 22 + 1/4 is almost horizontal, the edge coordinates of the scanline intersection of y = 22 (integer: x = 426) and the sub-scanline intersection of y = 22 + 1/4. The edge coordinates (real number: x = 423 + 3/4) are far apart. The coordinate difference is 9 times 1/4, and cannot be expressed in 3 bits. When detecting such a case, the coordinate hint-attached edge data generation unit 3005 does not perform processing for obtaining a Sub-Scanline intersection having y of 22 + 1/4 or more. In this case, an integer edge is newly added as a temporary coordinate point, and a higher resolution coordinate is expressed by using the difference.

  In this case, the edge data generation unit with coordinate hint 3005 holds 5-bit data in which “0” is added to the Sub-Scanline intersection coordinate value (3 bit value and sign bit) and “0” is added to the IsEdge flag. Next, the edge data generation unit with coordinate hint 3005 calculates a new fictitious Scanline intersection (temporary coordinate point) with an integer y coordinate value (y = 22). The edge data generation unit with coordinate hint 3005 rounds up the above-mentioned Sub-Scanline intersection value (real number: x = 423 + 3/4) from a real value to an integer (ceil), and calculates this as a new fictitious edge coordinate value (x = 424). , Y = 22) is set as a 15-bit integer. Further, the edge data generation unit with coordinate hint 3005 sets and holds “0” in the IsEdge flag. This is the edge for the fictitious Scanline intersection. The coordinate hint-attached edge data generation unit 3005 sets and holds 1/4 coordinate hint information (2 bits) as “00” for this imaginary edge.

  The edge data generation unit 3005 with coordinate hints uses the edge coordinate value (real number: x = 423 + 3/4) of the Sub-Scanline intersection of y = 22 + 1/4 for the edge coordinate value (x = 424) of the fictitious Scanline intersection. Recalculate as difference. The coordinate hint-attached edge data generation unit 3005 holds 5 bit data in which “−1” is added to the Sub-Scanline intersection coordinate value (3 bit value and sign bit) and “1” is added to the IsEdge flag. After that, the edge data generation unit with coordinate hint 3005 performs processing for obtaining the Sub-Scanline intersection with the real number y coordinate values of y = 22 + 2/4 and y = 22 + 3/4, and generates and holds a total of 15-bit data. To do.

  Data including the edge coordinate values obtained by the above scan line conversion is edge data, and is passed to the document image data generation unit 3007 in the format of the data structure shown in FIG.

  A characteristic of the data structure shown in FIG. 4 is that, among edge coordinate data, edge data 4200 consisting of integer values and coordinate hint information 4300 including 1/4 coordinate hint information for reproducing real number coordinate values are separated. It is a point that is configured. Further, the coordinate hint information 4300 of the 1/4 coordinate hint information of the Scanline intersection is adjacent to the edge data 4301 to 4303 of the Sub-Scanline intersection. Taking such a data structure leads to an improvement in data access speed in an image generation process described later.

[Processing flow]
Next, using the flowcharts of FIGS. 7, 8, and 9, the box printing function program operating on the control device 100 of the digital multifunction peripheral 403 converts the edge data 4200, 4300, 4301 to 4303 to the edges on the device coordinate system. The conversion process will be described. Each drawing is a part of a process in which the edge data expansion unit 3011 with coordinate hints of the box printing function program converts the edge data 4200, 4300, 4301 to 4303 into edges on the device coordinate system. Note that this embodiment is realized by the CPU 101 reading and executing the box printing function program stored in the ROM or the like.

  First, it demonstrates using FIG. In step S <b> 701, the coordinate hint-added edge data expansion unit 3011 determines an enlargement / reduction ratio (hereinafter, pixel magnification) of each pixel of the image data when the box print function program generates a print output image. Here, the “pixel magnification” indicates a value of how many pixels on the device coordinate system plane drawn by the marking unit 320 of the printer unit 300 corresponds to 1 pixel defined in the src coordinate system. . The origin of the device coordinate system is the upper right, is defined by a planar coordinate system in which the horizontal direction is X and the vertical direction is Y, and the unit of the device coordinate system is 1 pixel drawn by the marking unit 320.

  The pixel magnification of the image data is calculated based on the print attribute of PageInfo 4100 in the document image data 3009 and the setting attribute value at the time of printing set by the user from the operation unit 150 and stored in the RAM 102 of the control device 100. The “print attributes” in the PageInfo 4100 used here are an aggregate print setting attribute, a page size attribute, and a resolution attribute, and some value is always set. The printing-time setting attribute values stored in the RAM 102 of the control device 100 are also an aggregate printing setting attribute, a page size attribute, and a resolution attribute, and have the same meaning as the printing attribute in the above-described PageInfo 4100. However, “default” can be specified as the setting value, and in this case, the value of the print attribute in the PageInfo 4100 is applied as it is.

  The printing setting attribute value stored in the RAM 102 of the control device 100 can be changed as a function of a box printing function program that operates on the control device 100. At that time, the setting attribute value at the time of printing is changed by reflecting the operation result of the operation unit 150 by the user. However, due to restrictions on the device configuration of the printer unit 300, there may be values that cannot be set for the resolution and page size. When the printing attribute value in the PageInfo 4100 and the printing setting attribute value stored in the RAM 102 of the control apparatus 100 are determined, the pixel magnification of the image data is uniquely determined. FIG. 11 shows an example of a combination 1101 in which the pixel magnification is uniquely determined based on the correspondence between the print attribute value and the print setting attribute value according to the present embodiment.

  In step S <b> 702, the edge data expansion unit 3011 with coordinate hints determines whether the pixel magnification is “1” (that is, whether or not the magnification is equal). When the Pixel magnification is “1” (YES in S702), the coordinate hint-attached edge data development unit 3011 performs the process shown in FIG. 8 using the edge data 4200. When the Pixel magnification is other than 1 (NO in S702), the coordinate hint-attached edge data expansion unit 3011 performs the processing illustrated in FIG. 9 using the edge data 4200, 4300, 4301 to 4303.

  FIG. 8 is a flowchart for explaining device coordinate conversion processing of edge data executed when the pixel magnification is “1” (S703 shown in FIG. 7). The device coordinate conversion process is started from the origin on the device coordinate system plane. In step S801, the edge data developing unit with coordinate hint 3011 confirms the Y coordinate value of the device coordinate system. The maximum Y coordinate value is a Y coordinate value corresponding to the lower limit of the image output area defined by the page size. If Y does not exceed the maximum value (NO in S801), the process proceeds to S802. If Y exceeds the maximum value (YES in S801), it is determined that page rendering has ended, and the process ends.

  In step S <b> 802, the coordinate hint-added edge data development unit 3011 obtains a y coordinate value on the src coordinate system plane to be drawn on the scan line of the Y coordinate value of the device coordinate system. Here, since the pixel magnification is “1”, y = Y. In step S <b> 803, the edge data expanding unit with coordinate hint 3011 detects edge data in the scan line specified by the y coordinate value in the src coordinate system from 4200. If there is no corresponding edge data (NO in S803), it is not necessary to draw anything on the scan line of the Y coordinate value of the device coordinate system, and the process proceeds to S807. If there is one or more edge data (YES in S803), the process proceeds to S804.

  In step S804, the edge data expanding unit 3011 with coordinate hints checks the value of the IsEdge flag in the edge data. When the IsEdge flag is “0” (NO in S804), since the edge is a fictitious edge, the process returns to S803. If the IsEdge flag is “1” (YES in S804), in S805, the edge data developing unit with coordinate hints 3011 acquires a 15-bit integer x coordinate value from the edge data. In step S <b> 806, the coordinate hint-added edge data expansion unit 3011 adds the X coordinate value of the device coordinate system and the address to the level information 4400 associated with the edge, and sends the edge information to the level processing unit 3013. To do. Here, since the pixel magnification is 1, X = x. Thereafter, the processing returns to S803, and the edge data developing unit with coordinate hint 3011 confirms the next edge data having the y coordinate value of the same src coordinate system.

  In step S807, the edge data expanding unit 3011 with coordinate hint increments the Y coordinate value of the device coordinate system, and the process returns to step S801.

  FIG. 9 is a flowchart for explaining the device coordinate conversion processing of edge data executed when the pixel magnification is other than 1 (S704 shown in FIG. 7). The device coordinate conversion process is started from the origin on the device coordinate system plane. In step S <b> 901, the edge data expansion unit 3011 with coordinate hints calculates the pixel magnification based on the print attribute value in the PageInfo 4100 and the set attribute value at the time of printing stored in the RAM 102 of the control device 100. Is “A”. In step S902, the edge data developing unit with coordinate hint 3011 confirms the Y coordinate value of the device coordinate system. If Y does not exceed the maximum value (NO in S902), the process proceeds to S903. If Y exceeds the maximum value (YES in S902), the processing is terminated assuming that page rendering has ended.

In step S <b> 903, the coordinate hint-added edge data development unit 3011 obtains the vertical value of the edge coordinate on the src coordinate system plane to be drawn on the scan line of the Y coordinate value of the device coordinate system. Here, the pixel magnification is A, and it is considered that there is a scan line that takes an integer coordinate value on the src coordinate system plane, and a sub-scan line for each coordinate value 1/4. In this case, if the integer part of the coordinate value of the src coordinate system to be obtained is y, it is only necessary to know the maximum combination of y and b that satisfies the following relational expression. In the present embodiment, b is one of 0, 1, 2, and 3.
y ≦ (Yb / 4) / A

  In step S <b> 904, the edge data expansion unit 3011 with coordinate hints generates scanline edge data in which coordinates are specified from a combination of y and b, which are integer parts of coordinate values in the src coordinate system, or edge data in the sub-scanline. , From edge data 4200, 4301-4302. If the edge data is not detected and does not exist (NO in S904), it is not necessary to draw anything on the scan line of the Y coordinate value of the device coordinate system, and the process proceeds to S914. If there is one or more edge data (YES in S904), the process proceeds to S905.

  In step S <b> 905, the edge data developing unit 3011 with coordinate hints acquires an integer edge coordinate value from the detected scanline edge data or the original scanline edge data associated with the detected sub-scanline. In step S906, the coordinate hint-added edge data development unit 3011 determines the value of b. If b = 0 (YES in step S906), it is determined that the scanline edge on the src coordinate system plane should be used, and the process advances to step S907. When b is 1, 2, or 3 (NO in S906), it is determined that the Sub-Scanline edge on the src coordinate system plane should be used, and the process proceeds to S910.

In step S907, the edge data expanding unit 3011 with coordinate hints checks the value of the IsEdge flag in the above-described scanline edge data. If the value of the IsEdge flag is “1” (YES in S907), the process proceeds to S908. If the value of the IsEdge flag is “0” (NO in S907), the edge data is an imaginary edge and not an edge to be drawn, so the process returns to S904. In step S908, the coordinate hint-attached edge data development unit 3011 acquires a 2-bit 1/4 coordinate hint associated with the edge information of Scanline and sets it as c. In step S909, the edge data expanding unit 3011 with coordinate hints calculates an X coordinate value of the device coordinate system of the edge using the following equation.
X = ceil (A (x−c / 4))
The function ceil () here is a function that rounds up the value.

  Then, the process proceeds to S913.

In step S <b> 910, the coordinate hint-added edge data expansion unit 3011 obtains a difference coordinate value from the b-th sub-scanline edge information associated with the above-described scanline edge information, and sets the difference coordinate value to “d”. Further, the edge data developing unit with coordinate hint 3011 acquires the IsEdge flag (edge data 4301 to 4303). In step S911, the edge data expanding unit 3011 with coordinate hints checks the value of the IsEdge flag. If the value of the IsEdge flag is “1” (YES in S911), the process proceeds to S912. If the value of the IsEdge flag is “0” (NO in S911), the edge data is an imaginary edge and not an edge to be drawn, so the process returns to S904. In S911, the edge data developing unit with coordinate hint 3011 calculates the X coordinate value of the device coordinate system of the Sub-Scanline edge using the following equation.
X = ceil (A (x + d / 4))
Then, the process proceeds to S913.

  In step S <b> 913, the edge data developing unit with coordinate hint 3011 adds the X coordinate value of the device coordinate system of the edge and the address to the level information 4400 associated with the edge, and sends the edge information to the level processing unit 3013. . Thereafter, the processing returns to S904, and the edge data developing unit with coordinate hint 3011 confirms the next edge data having the y coordinate value of the same src coordinate system. In S914, the edge data expanding unit 3011 with coordinate hint increments the Y coordinate value of the device coordinate system, and returns to S902.

  As described in the description of FIGS. 8 and 9, in the process of FIG. 8 executed when the enlargement ratio is 1 time, only the edge data 4200 is accessed among the edge data in the document image data 3009. On the other hand, in the processing of FIG. 9 executed when the enlargement ratio is other than “1”, all of the edge data 4200, coordinate hint information 4300, and edge data 4301 to 4303 in the document image data 3009 are accessed. The document image data 3009 can be generated with an accuracy of 1/4 pixel unit by utilizing the hint information. However, by arranging only the edge data 4200 in an independent data area, the processing speed with the enlargement ratio “1” is not lowered. Further, by arranging the coordinate hint information 4300 and the edge data 4301 to 4303 in adjacent data areas, it is possible to efficiently perform image generation processing with enlargement / reduction.

  Further, even when a low-resolution drawing object and a high-resolution drawing object are mixed, it is possible to obtain a high-quality image in which a gap at the boundary is not conspicuous.

  Furthermore, when rendering a low-resolution rendering object without scaling, it is possible to generate an image without reducing the speed.

  Further, in this embodiment, the coordinate correction and the corresponding data structure are described using the ¼ coordinate. However, the present invention is not limited to this, and more detailed coordinate additional information may be set. . In this case, the configuration of the edge data shown in FIGS. 4 and 5 is also changed.

<Second embodiment>
In the first embodiment, the document image data processing apparatus includes a process for generating document image data 3009 from the PDL data 3001 in the control apparatus 100 and a process for generating a print output image from the document image data 3009. Explained.

  These two processes do not need to operate on the same digital multi-function peripheral. The document image data 3009 is in a format that can be output from print engines having various resolutions by including edge data with coordinate hints.

  Even if the processing performed in each step (3001 to 3009) shown on the left side of FIG. 3 and the processing performed in each step (3009 to 3016) shown on the right side of FIG. Good. At that time, the document image data 3009 is transferred to the HDD of another digital multi-function peripheral via the network. Alternatively, it may be copied to the HDD of another digital multi-function peripheral via magnetic media, rewritable optical media, flash memory, or the like.

  Thereby, the effect similar to 1st embodiment can be acquired.

<Other embodiments>
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 (10)

An image processing apparatus that generates drawing data from PDL data described in an input page description language,
Drawing object generation means for interpreting the PDL data and generating a drawing object;
Generating means for quantizing the coordinate value of each pixel included in the drawing object generated by the drawing object generating means at a predetermined resolution, and generating drawing data;
Holding means for holding, as additional information of coordinate values, values to be truncated when quantizing the coordinate values at the defined resolution in the generating means;
The holding means holds the additional information in a region different from the coordinate value at the predetermined resolution obtained by quantization of the drawing data generated by the generating means. . Rendering means for rendering the drawing data;
And a correction unit that corrects a coordinate value quantized at the predetermined resolution using the additional information when the rendering resolution by the rendering unit is not the predetermined resolution. The image processing apparatus according to claim 1.   3. The image according to claim 2, wherein the correction unit does not correct the coordinate value using the additional information when a resolution of rendering by the rendering unit is the same as the predetermined resolution. Processing equipment. A determination unit for determining an attribute of the drawing object generated by the drawing object generation unit;
The holding unit holds, as drawing data, data that is not quantized by the generation unit for the drawing object when the attribute of the drawing object is a predetermined attribute. The image processing device according to any one of claims 1 to 3.   The image processing apparatus according to claim 4, wherein the predetermined attribute is that the drawing object is a thin line or a character smaller than a predetermined size. The additional information indicates a coordinate value at a higher resolution than the determined resolution,
6. The image processing apparatus according to claim 1, wherein the coordinate value at the high resolution is defined by a difference from the coordinate value at the predetermined resolution.   The holding unit adds a temporary coordinate point when the difference between the coordinate value at the predetermined resolution and the coordinate value at the high resolution is larger than a predetermined number of bits for defining the difference. The image processing apparatus according to claim 6, wherein the coordinate value at the high resolution is defined by a difference from the coordinate value of the temporary coordinate point instead of the coordinate value at the predetermined resolution.   3. The image processing according to claim 2, wherein another image processing apparatus different from the image processing apparatus having the drawing object generation unit, the generation unit, and the holding unit includes the rendering unit and the correction unit. apparatus. An image processing method for generating drawing data from PDL data described in an input page description language,
A drawing object generation means for interpreting the PDL data and generating a drawing object;
A generating step of generating a drawing data by quantizing a coordinate value of each pixel included in the drawing object generated in the drawing object generating step with a predetermined resolution;
A holding unit holding a value to be truncated by quantization in the storage unit as additional information of the coordinate value when the coordinate value is quantized at the determined resolution in the generation step;
In the holding step, the additional information is held in a region different from the coordinate value at the predetermined resolution obtained by quantization of the drawing data generated in the generating step. . Computer
A drawing object generating means for interpreting PDL data described in a page description language and generating a drawing object;
Generating means for quantizing the coordinate value of each pixel included in the drawing object generated by the generating means at a predetermined resolution, and generating drawing data;
When the coordinate value is quantized with the determined resolution by the generating means, function as a holding means for holding a value to be truncated by quantization as additional information of the coordinate value,
The storage unit stores the additional information in a region different from the coordinate value at the predetermined resolution obtained by quantization of the drawing data generated by the generation unit.

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