JPH05342314A - Picture processor - Google Patents

Abstract

PURPOSE:To efficiently handle PDL data. CONSTITUTION:In a color PDL printer, a picture memory 100 having a low resolution and a high gradation and a picture memory 15 having a high resolution and a low gradation are provided and a CPU 1 selects the picture memory to be expanded by the kinds of PDL data, and a synthesizing circuit 102 synthesizes outputs from picture memories 15 and 100 at the time of printing, thus a character picture as well as a gradation picture with a small number of memories are suitably printed. Further, a preference information memory 103 having a high resolution is provided, and the CPU 1 sets the preference information of two pictures at the time of expansion, and the synthesizing circuit 102 synthesizes the outputs while switching the picture memory to the preferred picture memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a page description language (hereinafter,
PDL data described in (PDL),
The present invention relates to an image processing apparatus that processes and outputs image data to an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, from a host computer or the like to PDL
(Page Description Language) A printer that receives data and forms an image is configured as shown in FIG. As shown in the figure, the PDL data sent from the host computer 12 via the interface 11 and the external interface circuit 6 is temporarily PDL data.
After being stored in the buffer 13, it is developed into raster image data by the CPU 1 and written in the full page image memory 7. At this time, the ROM 2 is used to hold a program, the RAM 3 is a work RAM for work, and the font ROM 4 is used to hold a font for converting a character code in PDL data into bit image data. .. Also, dither pattern ROM5
Holds a dither pattern when using the dither method which is one of the binarizing means, and 10 is a CPU bus connecting them.

On the other hand, the image forming section 8 is, for example, an electrophotographic black-and-white binary printer, and has a full-page image memory 7
An image is formed based on the image signal 53 read from the. Synchronous signal 5 from address generator 9 and image forming unit 8
Based on 1, the read address from the full page image memory 7 is generated. Generally, the printing speed of an electrophotographic printer is high, and the full page image memory 7
The image signal 53 read out from is also much faster than the image writing speed to the full page image memory 7 by the CPU 1. Further, in general, an electrophotographic printer cannot stop halfway while printing one sheet, so that it is necessary to expand all the image data required for printing in a full page image memory for one page.

[0004]

The above-mentioned conventional example is black and white 2
Although it is applied to a value printer, when this is applied to a full-color printer, there arises a problem that the number of bits of image data of each pixel is larger than that in a monochrome binary printer. If a full-color printer has four color components and each pixel has 8 bits of data for each pixel that corresponds to the resolution of the printer in a one-to-one relationship, it is 32 times as large as a monochrome binary printer with the same resolution. Memory capacity is required. Further, if the image memory 7 is configured with a resolution lower than that of the printer and is enlarged at the time of printing, the character image is deteriorated. On the other hand, if the number of bits per component is reduced for each pixel, the number of gradations in the gradation image is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an image processing apparatus capable of efficiently handling PDL data.

[0006]

[Means for Solving the Problems]
To achieve the object, an image processing apparatus according to the present invention is a PDL in an image processing apparatus connected to an image forming unit.
An input means for inputting data and a first resolution having a first resolution
Raster image memory means, second raster image memory means having a second resolution, and raster image development at the first and second resolutions based on the input PDL data, and the first and second raster image memory means respectively. A rasterizing means for writing in the second raster image memory means, and a rasterizing means for reading the raster image from the second raster image memory after the rasterizing means and enlarging the raster image to obtain the image of the first resolution. A synthesizing unit for synthesizing the enlarged image and the image read from the first raster image memory, and a transferring unit for transferring the synthesized image to the image forming unit.

[0007]

According to this structure, the input means inputs the PDL data, the first raster image memory means has the first resolution, the second raster image memory means has the second resolution, and the decompressing means, Based on the input PDL data,
The raster image is developed into first and second resolutions and written in the first and second raster image memory means, respectively, and the enlarging means enlarges the raster image to obtain an image of the first resolution and synthesizes the raster image. The means combines the magnified image with the image read from the first raster image memory, and the transfer means transfers the combined image to the image forming means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a block diagram showing an image processing apparatus 50 compatible with color PDL according to a first embodiment of the present invention.

As shown, the host computer 12
The PDL data sent from the interface 11 through the external interface circuit 6 is temporarily stored in the PDL data buffer 14 and then expanded into raster image data by the CPU 1 to generate the image memory 15-1 to 4 or the image memory. 100-1 to 100-4, respectively. The image memory 15 has a resolution of 400 dpi corresponding to the print resolution of the image forming unit 8 and has one pixel and one bit gradation number per color component. On the other hand, the image memory 100
Has a resolution of 100 dpi and has a gradation number of 8 bits for each pixel and one color component. PD that makes up one page
Each portion of the L data is expanded in either image memory according to the characteristics of the image described. At this time, the expansion is performed according to the resolution and the number of gradations of each image memory.

The raster images developed in the two image memories are read out at the time of printing, and the image memory 10
The output image from 0 is adjusted by the enlargement circuit 101 to the resolution of the printer and then combined by the combining circuit 102. In the case of the present embodiment, the enlarging circuit 101 performs the primary interpolation enlarging to 4 times in the vertical and horizontal directions. The priority information memory 103 is a 400-dpi, 1-bit memory, and generates a signal for switching two images in the synthesizing circuit 102. The contents of the priority information memory are set by the CPU 1 when the PDL data is expanded in the two image memories.

The ROM 2 is used to hold a program showing an image processing procedure, the RAM 3 is a work RAM for work, and the font ROM 4 is for converting the character code in the PDL data into bit image data. Used to hold fonts. Further, the dither pattern ROM 5 holds a dither pattern when the dither method which is one of the binarizing method is used, and 10 is a CPU bus connecting them.

On the other hand, the image forming section 8 forms an image in a frame-sequential manner with respect to a plurality of output color components (C, M, Y, Bk).
-1 to 4 and each of the image memories 100-1 to 100-4 correspond to each other. In addition, the address generator 9 uses the synchronization signals 51 from the image forming unit 8 to generate the image memories 15-1 to 15-4.
And read-out address 5 of each image memory 100-1 to 100-4
2 is generated.

FIG. 2 is a diagram for explaining PDL data. ADOBE Post Script
As shown in FIG. 2A, the PDL typified by the (registered trademark) language describes an image of one page as (i) an image description for each character, (ii) an image description as a graphic code, and (iii).
It is a language for combining and describing elements such as image description by raster image data, and the data described by this is PDL data.

FIG. 2 (b) shows an example of description by a character code. 1100 is a description for designating the color of characters,
In the parentheses, the luminances of Red, Green, and Blue are shown in order. The minimum is 0.0 and the maximum is 1.0. In 1100, the character is designated to be black. Next, 1101 shows the character string "I" in the variable String1.
C ”is substituted. Next, at 1102, the first and second parameters indicate the x coordinate and the y coordinate of the start position coordinates on the paper on which the character string is laid out, the third parameter indicates the character size, and The four parameters indicate the character spacing, and the fifth
The parameter indicates the character string to be laid out. In short, 1102 is an instruction to lay out the character string "IC" with a size of 0.3 and an interval of 0.1 from the coordinates (0.0, 0.0).

FIG. 2C shows an example of the description by the graphic code. As with 1100, 1103 designates a line color, and here, Red is designated. Then 110
4 is for designating to draw a line, and
Two parameters are the starting coordinates of the line, and third and fourth parameters are the ending coordinates of the line, respectively. The fifth parameter indicates the line thickness.

FIG. 3A shows an example of description by raster image data. Reference numeral 1105 designates the raster image as a variable image1.
Is assigned to. Here, the first parameter represents the image type of the raster image and the number of color components, the second parameter represents the number of bits per color component, and the third and fourth parameters represent the x direction and the y direction of the raster image. Indicates the image size. The fifth and subsequent parameters are raster image data. The number of raster image data is the product of the number of color components forming one pixel and the image size in the x and y directions. 1
At 105, the RGB image has three color components (Red, Gr
The number of raster image data is 3 × 5 × 5 = 75. FIG. 3B shows a state in which the graphic description of FIGS. 2B, 2C, and 3A is interpreted in one page and expanded into raster image data. R100, 101, and 102 are expanded PDL data of FIGS. 2B, 2C, and 3A, respectively. For example, of these PDL data, the character image R100 and the graphic image R in which resolution is important
Reference numeral 101 is expanded in the image memory 15 of high resolution and low gradation number, while gradation image R102 is expanded in the image memory 100 of low resolution and high gradation number.

FIGS. 4 and 5 are views showing the relationship between the image in the image memory 15, the image in the image memory 100, and the priority information in the priority information memory 103. As shown in FIG. 4, the enlarged image 104 of the image in the image memory 100 and the image 105 in the image memory 15 are the same as the priority information memory 10
An output image 107 is formed by switching and synthesizing according to the priority information 106 in 3.

In general, a signal for switching synthesis is required to switch and synthesize two images. As this method, (1) a rectangular area generating means is provided, and switching composition is performed for each rectangular area. (2) Switching composition is performed according to the presence / absence of one data. (3) Switching information for each pixel or every several pixels is held in the priority information memory, and the output is used to perform switching synthesis. There are three types. Any of the embodiments may be adopted as the embodiment of the present invention, but the third method is adopted in this embodiment. The third method is more expensive than other methods because it requires a memory, but it requires exactly 2 pixels per pixel.
You can switch and combine two images. In the PDL data, the images are often overlapped on a pixel-by-pixel basis, and if they are expanded in different memories, they cannot be combined by the first method. Further, in the PDL data, when there are two or more descriptions for one pixel on the paper, the latter description is valid. However, with the second method, either image is always valid. On the other hand, according to the third method, when the CPU 1 expands the PDL data, it is possible to know which description comes later, so that the information may be written in the priority information memory.

FIG. 5 is a diagram showing the composition of two images for the diagonal edge portion of the gradation image developed in the image memory 100. Since the image in the image memory 100 is magnified four times before composition, the boundary of the image becomes a unit of 4 pixels, and the diagonal line becomes a step shape of a unit of 4 pixels (100 dpi). Although this can be mitigated by performing the linear interpolation expansion, it does not disappear. Therefore, in the present embodiment, when the gradation image is expanded in the image memory 100, the edge portion is expanded in the image memory 15, and the priority information memory is set so that the contents of the image memory 15 are prioritized. The edge portion has a high resolution of 400 dpi. As shown in FIG. 5, the image in the image memory 100 has a high gradation but a stepwise enlarged image 108, and the image 1 in the image memory 15 has a low gradation but an image 1 with smooth edges.
09 is switched and combined by the priority information 110 in the priority information memory 103 to form an output image 111 with a smooth edge and a high tone inside.

FIG. 5 is a control flowchart of the image processing apparatus of this embodiment. First, in S101, one unit of PDL data is received. One unit may be several bytes or one page, but may be a unit suitable for processing, for example, one line unit in FIGS. 3 and 4. In S102, the attention P
The DL data is a raster image (for example, 110 in FIG. 3A).
If it is a raster image, S10 is determined.
In 3, the image memory 100 is loaded. At this time, 100dp
i, each color component is processed by 8 bits. Further, at the same time as the development in the image memory 100, “1” indicating the priority of the image 100 is written in the corresponding location of the priority information memory 103. Further, in S104, the edge portion of the raster image is expanded in the image memory 15. At this time, processing is performed with 400 dpi and each color component of 1 bit. Further, at the same time as the development in the image memory 15, “0” indicating the priority of the image memory 15 is written in the corresponding location of the priority information memory 103.
On the other hand, when the PDL data of interest in S102 is not a raster image, the PDL data of interest in S105 is a character image (eg, 1102 in FIG. 2A) or a graphic image (eg, 1104 in FIG. 2C). It is determined whether or not there is, and in that case, it is expanded in the image memory 15 in S106. At this time, 40
It is processed with 0 dpi and 1 bit of each color component. Further, at the same time as the development in the image memory 15, the priority information memory 10
"0" indicating the priority of the image memory 15 in the corresponding location of 3
Write. Further, in S103, if the data is other data (for example, 1100 in FIG. 2A), processing such as setting to an internal variable is performed in S107.

Then, in step S108, the PDL data for one page is received, and it is determined whether the development is completed. Since normal PDL data includes information indicating the end of a page such as an EOF (End Of File) symbol and information for instructing print start, this is used for determination. If it is not included, S101 to S108 are repeated. If it is included, the raster image data expanded in the image memory 15 and the image memory 100 is read and transferred in S109, and the image forming unit 8 forms one page. I do.

Although the image forming section 8 is separated from the image processing section 50 in this embodiment, it may be integrated.

[0023]

[Other Examples]

<Second Embodiment> FIG. 7 is a block diagram showing a color PDL compatible image processing apparatus 50 according to a second embodiment of the present invention. The first difference from the first embodiment is that in the first embodiment, the P
Although DL data was received, this is the point of reading PDL data from the internal floppy disk 59 in this embodiment. A hard disk or the like may be used instead of the floppy disk, and PDL data created by an application program (not shown) may be transferred on the main memory.

The second point is that in the first embodiment, it is 4
The 00 dpi image memory 15 and the priority information memory 103 were separately configured, but in this embodiment, they are common. By doing so, the processing time can be reduced because the 400 dpi image and the priority information can be accessed at the same time. Bit with different priority information from 400 dpi image
Is used and is separated at the time of reading.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0026]

As described above, according to the present invention,
The color PDL printer has an image memory with low resolution and high gradation number and an image memory with high resolution and low gradation number. The image memory to be developed is selected according to the type of PDL data, and output from two types of image memory at the time of printing. By synthesizing the above, it is possible to realize a PDL printer that can suitably print a character image and a gradation image with a small memory. Further, it has a high-resolution priority information memory, sets priority information of two images at the time of expansion, and outputs from two types of image memories are switched and combined by the contents of this memory, whereby accurate composition can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an image processing apparatus according to a first embodiment.

FIG. 2 is a diagram for explaining PDL.

FIG. 3 is a diagram for explaining PDL.

FIG. 4 is a diagram for explaining composition.

FIG. 5 is a diagram for explaining composition.

FIG. 6 is a flowchart showing a procedure of the first embodiment.

FIG. 7 is a block diagram of an image processing apparatus according to a second embodiment.

FIG. 8 is a block diagram of a conventional image processing apparatus.

[Explanation of symbols]

 1 CPU 2 ROM 3 RAM 4 font ROM 5 dither pattern ROM 6 external interface 8 image forming unit 9 address generating unit 12 host computer 13 PDL buffer 14-1 to 15-4, 100-1 to 4 image memory 101 enlargement circuit 102 synthesis Circuit 103 Priority information memory

Claims (4)

[Claims] 1. An image processing apparatus connected to an image forming means, wherein input means for inputting PDL (page description language) data, first raster image memory means having a first resolution, and second resolution are provided. A second raster image memory unit that has the raster image data and raster image data that is expanded into raster images at the first and second resolutions based on the input PDL data.
A rasterizing means for writing in the second raster image memory means, and after the rasterizing means, the raster image is read from the second raster image memory, the raster image is enlarged, and the first raster image is expanded.
Means for obtaining an image having a resolution of 1., a combining means for combining the enlarged image with an image read from the first raster image memory, and a transfer for transferring the combined image to the image forming means. An image processing apparatus comprising: 2. The image processing apparatus according to claim 1, wherein the number of gradations used in the second raster image memory means is larger than the number of gradations used in the first raster image memory means. 3. The priority information storage means having the first resolution is provided, and the synthesis means performs synthesis in accordance with a priority signal read from the priority information storage means. 2. The image processing device according to 2. 4. The image processing apparatus according to claim 1, wherein the developing means develops an edge portion of an image developed in the second raster image memory means into the first raster image memory means. ..