JP2005020325A - Image processor and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To speed up an image processing of a bit map image by adding edge detection information when printing data formed of PDL is rasterized so as to improve processing performance of a printing system. <P>SOLUTION: An image processor is provided with an input means inputting image data, a development means developing image data in bit map image data, an edge extraction means extracting a pixel of an edge part in developed image data in the development means, an edge information map generation means generating an edge information map having information showing how many pixels ahead from a target pixel in a raster scan direction there exists an edge in accordance with the bit map image data developed in the development means and a determination result of the edge extraction means, and a deciding means deciding a range where a prescribed image processing in bit map data based on the edge information map generated in the edge information map generation means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and an image processing method.
[0002]
[Prior art]
Conventionally, a method for improving the quality of an output image when a page description language is received and a color image is developed and output to a color printer will be described with reference to FIG.
[0003]
The image processing system shown in FIG. 2 is a system that creates pages such as text, graphics, and images using a host computer and outputs them in a hard copy with a laser beam printer, an inkjet printer, or the like. Reference numeral 202 denotes an application operating on the host computer 201. Print data created by the application 202 is transmitted to the printer driver 203 via an operating system (OS) (not shown).
[0004]
The print data is represented as a set of command data representing graphics, characters, and the like, and these command data are transmitted to the printer driver 203. A series of command data is expressed as a language system called PDL (page description language).
[0005]
The printer driver 203 transfers the received PDL command to the rasterizer 205 in the printer controller 204. The rasterizer 205 develops characters, graphics, and the like expressed by the PDL command into a two-dimensional bitmap image for actual printer output. The developed bitmap image is stored in the memory 206. The bitmap image stored in the image memory 206 is subjected to image processing necessary for printing by the image processing unit 208 and transmitted to the color printer 207. The image forming unit 209 forms an image based on the bitmap image on the recording medium. (Patent Document 1)
[Patent Document 1]
JP 2000-259819 A
[Problems to be solved by the invention]
However, the following problems occur in the conventional image processing system. When correcting color misregistration or the like, it is necessary to perform filter processing for edge detection on the bitmap image developed by the rasterizer 205, but enormous amount of computation is required to perform filter processing on the entire bitmap image. This is necessary and causes a reduction in processing speed of the image processing system.
[0007]
In order to solve such a problem, Japanese Patent Laid-Open No. 2000-259819 performs edge detection when developing print data into a bitmap, generates an edge information map corresponding to the bitmap image, and generates edge information during image processing. A method for performing image processing only on a necessary area with reference to a map is described. In this method, since edge information is added to each pixel of the bitmap image, it is necessary to access all the pixel data when performing processing while simultaneously referring to the bitmap image data and the edge information by SIMD calculation. There is.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an image processing apparatus according to the present invention comprises the following arrangement. That is, an input means for inputting image data;
Expansion means for expanding image data into bitmap image data;
Edge extracting means for extracting pixels of the edge portion of the developed image data in the developing means;
Edge information for generating an edge information map having information indicating how many pixels ahead from the target pixel in the raster scan direction according to the bitmap image data expanded by the expansion unit and the determination result of the edge extraction unit Map generation means;
Determining means for determining a range for performing predetermined image processing in the bitmap data based on the edge information map generated by the edge information map generating means;
Is provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
FIG. 1 is a block diagram showing a schematic configuration of an image processing system according to an embodiment of the present invention. An image processing system according to an embodiment of the present invention includes a host computer 101, an application 102, a printer driver 103, a printer controller 104, a rasterizer 105, a memory 106, an image area separation and image processing unit 107, a color printer 108, and an image forming unit. 109.
[0011]
(Example 1)
In FIG. 1, the print data created by the application 102 is expressed by a language system called PDL. The PDL is roughly composed of three objects: a character object, a graphic object, and a bitmap object. The printer driver 103 sends a command sequence representing an object such as a character, graphic, or bitmap to the rasterizer 105. The rasterizer 105 converts the received command sequence into two-dimensional bitmap image data, and at the same time outputs an edge information map that is a feature of the present invention.
[0012]
The edge information map is a two-dimensional information in which each pixel is provided with information indicating how many pixels ahead from the target pixel in the raster scan direction. The memory 106 stores the correspondence for each pixel so that the two-dimensional image data and the edge information map are possible.
[0013]
FIG. 3 is a diagram illustrating an example of an edge information map associated with each pixel according to the first embodiment. FIG. 3 shows an image in which an alphabet “H” as a character object is superimposed on a bitmap object. When converting to a two-dimensional bitmap, information indicating how many pixels ahead there is in the raster scan direction from the pixel of interest is output according to the determination result of the edge extraction means, and an edge information map as shown in FIG. Is generated. For example, in the uppermost line in FIG. 3, since no edge exists, the left end of the edge information map outputs 0 (that is, information indicating that no edge exists in the raster scan direction from the pixel of interest). .
[0014]
In the third line from the top in FIG. 3, an edge exists at the fourth, fifth, twelfth, and thirteenth pixels from the left. Therefore, the third pixel at the first pixel of the edge information map (3 from the first pixel toward the raster scan direction). Information indicating that an edge exists in the pixel) 1 in the fourth pixel (information indicating that an edge exists in the first pixel in the raster scan direction from the fourth pixel) 7 in the fifth pixel (5 Information indicating that an edge exists at the seventh pixel from the pixel toward the raster scan direction), 1 at the 12th pixel (indicating that an edge exists at the first pixel from the 12th pixel toward the raster scan direction) Information), 0 at the 13th pixel (information indicating that no edge exists from the 13th pixel toward the raster scan direction) To output.
[0015]
In the eighth line from the top in FIG. 3, an edge is present at the fourth and thirteenth pixels from the left. Therefore, the third pixel is the first pixel in the edge information map (the first pixel is the third pixel from the first pixel toward the raster scan direction). Information indicating that an edge exists at the ninth pixel in the raster scan direction from the fourth pixel), and 0 at the thirteenth pixel (raster from the thirteenth pixel). Information indicating that no edge is present in the scanning direction is output.
[0016]
An example of storing the edge information map in the memory is shown in FIG. As shown in FIG. 4, when RGB data is configured in one pixel, it is embedded so as to be added to the RGB information of each pixel.
[0017]
Next, a processing flow of processing executed in the first embodiment will be described with reference to FIG.
[0018]
First, in step S <b> 101, each object of image data composed of a plurality of input objects is developed into bitmap image data by the rasterizer 105, and the developed bitmap image data is stored in the memory 106. In step S102, an edge information map of bitmap image data is generated based on the developed bitmap image data and object attributes, and the generated edge information map is stored in the memory 106. In step S103, the image area separation and image processing unit 107 performs image processing while determining a range to be subjected to image area separation processing in the bitmap image data based on the generated t-edge information map, and the obtained image Is transmitted to the color printer 108, and an image is formed on the recording medium by the image forming unit 109.
[0019]
【The invention's effect】
As described above, according to the invention described in claim 1 of the present application, when performing color misregistration processing of an image composed of a plurality of objects, only the necessary area of the bitmap image data is accessed and color misregistration is performed. Since correction processing can be performed, a high-speed image processing system can be constructed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an image processing system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a schematic configuration of a conventional image processing system.
FIG. 3 is a diagram illustrating an example of a configuration of an edge information map according to the first embodiment.
FIG. 4 is a diagram illustrating an example of a configuration of an edge information map according to the first embodiment.
FIG. 5 is a flowchart showing a processing flow executed in the first embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Host computer 102 Application 103 Printer driver 104 Printer controller 105 Rasterizer 106 Memory 107 Image area separation processing and image processing unit 108 Color printer 109 Image forming unit

Claims (1)

Input means for inputting image data;
Expansion means for expanding image data into bitmap image data;
Edge extracting means for extracting pixels of the edge portion of the developed image data in the developing means;
Edge information for generating an edge information map having information indicating how many pixels ahead from the target pixel in the raster scan direction according to the bitmap image data expanded by the expansion unit and the determination result of the edge extraction unit Map generation means;
Determining means for determining a range for performing predetermined image processing in the bitmap data based on the edge information map generated by the edge information map generating means;
An image processing apparatus comprising:

Images