JPH1198360A - Device and method for processing picture and computer readable storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a gradation processing corresponding to the resolution of an image object when an image object such as a photograph are included in input picture data. SOLUTION: Whether or not an image object is included in input picture data is judged (604), and when the image object is included, the resolution and threshold value of the image object are compared (S606). A gradation processing is operated based on the resolution of the image object (S607, S608). Then, output picture data are prepared, and picture data for one page are outputted (S611).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, an image processing method, and a computer-readable storage medium used for the same, for example, an image processing capable of processing input image data described in a page description language. It is.

[0002]

2. Description of the Related Art Image processing apparatuses such as printers and copiers,
When outputting an image object such as a photograph included in input image data described in a page description language, pseudo gradation expression is performed by a dither method, an error diffusion method, or the like.
In an electrophotographic color image processing apparatus, the gradation can be expressed by changing the pulse width of the laser light according to the gradation of the image object.

[0003]

However, the above technique has the following problems. When performing gradation processing on an image object such as a photograph included in input image data described in a page description language, a processing method corresponding to the resolution of the image object cannot be performed. Even if the pulse width modulation method is used, the image quality deteriorates.

An object of the present invention is to solve the above-mentioned problem, and to perform image processing capable of performing gradation processing according to the resolution of an image object such as a photograph included in input image data described in a page description language. An object is to provide an apparatus, a method, and a computer-readable storage medium used in the apparatus, the method, and the method.

[0005]

The present invention has the following configuration as one means for achieving the above object.

[0006] An image processing apparatus according to the present invention comprises: an obtaining unit configured to obtain a resolution of an image object included in input image data described in a page description language; Processing means for applying to the object.

An image processing method according to the present invention obtains a resolution of an image object included in input image data described in a page description language, and performs gradation processing on the image object according to the resolution of the image object. It is characterized by the following.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image processing apparatus and an image processing method according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a multilevel dither method according to an embodiment of the present invention.

An example (4 × 4) of a dither matrix used in the multi-value dither method is shown. In FIG. 1, a [i],
b [i] and c [i] (i = 1 to 16) are predetermined thresholds. The dither processing is performed by an algorithm similar to the binary dither method, but in the case of the multi-value dither method, one pixel has a plurality of thresholds. Thresholds a [i], b
[I] and c [i] (i = 1 to 16) are obtained when the density value of the input image data exceeds the value of a [i] as shown in FIG.
A region corresponding to 30% of the area of one pixel is painted, and similarly, if it exceeds the value of b [i], 60%, and if it exceeds the value of c [i], 100% of the region is painted. Further, the rate of painting the pixel area and the way of painting the pixel (in the present embodiment, painting from the center of the pixel) are not limited to this, and may be determined according to the characteristics of the printer engine. It can be changed as appropriate.

FIG. 3 shows one embodiment of the present invention.
It is a figure for explaining a difference of output result of 0dpi and 600dpi pulse width modulation system.

PWM2 represents the output result of the 200 dpi pulse width modulation method, and PWM1 represents the output result of the 600 dpi pulse width modulation processing method. The HRESO signal is
This is a select signal for switching the processing between the 200 dpi pulse width modulation method and the 600 dpi pulse width modulation method. Generally, the 200 dpi pulse width modulation method has better gradation reproducibility than other gradation processing.

FIG. 4 shows an example of the configuration of an image processing apparatus (hereinafter, referred to as a "printer") having a laser beam printer according to an embodiment of the present invention as a printer engine.

The printer main body 4000 is provided with input image data (character codes, forms,
Based on a macro command, a corresponding character pattern, form pattern, or the like is created, and an image is formed on a recording medium such as recording paper. Here, it is assumed that the input image data is described in a page description language.

The operation panel 4012 includes switches for operating the printer by a user, an LED display, and the like. The printer controller 4001 controls the entire printer main body 4000 and analyzes input image data sent from the host computer. The printer controller 4001 mainly converts information such as a character code into a video signal having a corresponding character pattern and outputs the video signal to a laser driver 4002.

A laser driver 4002 is a circuit for driving the semiconductor laser 4003, and switches on / off a laser beam 4004 emitted from the semiconductor laser 4003 according to an input video signal. Laser light 4
004 is swung in the left and right direction by a rotating polygon mirror 4005 to scan and expose the electrostatic drum 4006. Thus, an electrostatic latent image of a character pattern is formed on the electrostatic drum 4006. This latent image is developed by a developing unit 4007 disposed around the electrostatic drum 4006, and then transferred to a recording medium such as recording paper. This recording paper is stored in a paper cassette 4008 attached to the printer 4000, and includes a paper feed roller 4009, a transport roller 4010,
The sheet is taken into the apparatus by the conveying roller 4011 and supplied to the electrostatic drum 4006. The printer body 4000
Has at least one external storage medium such as an IC card, and can connect an optional font card in addition to the built-in font.

FIG. 5 is a block diagram showing an example of a system configuration of an image processing apparatus according to an embodiment of the present invention.

The host computer 5000 has a CPU
1, RAM 2, ROM 3, system bus 4, keyboard controller (KBC) 5, CRT controller (CR
TC) 6, memory controller (MC) 7, printer controller (PRTC) 8, keyboard (KB) 9, C
An RT display (CRT) 10 and an external memory 11 are provided.

The CPU 1 performs image processing of input image data including photographs, figures, images, characters, tables (including spreadsheets, etc.) in accordance with various program steps such as image processing programs and control programs stored in the ROM 3. It controls each device connected to the system device 4.
Further, for example, as an image of the same image as when the input image data stored in the RAM 2 is output to the printer, C
It can be displayed on RT10.

The RAM 2 is a storage unit used as a main memory or a work area of the CPU 1. ROM3
Stores an image processing program, a control program, and the like,
Also, font data and the like used when performing the image processing are stored.

The system bus 4 includes a CPU 1, a RAM 2,
It interfaces with the ROM 3, the keyboard controller 5, the CRT controller 6, the memory controller 7, and the printer controller 8. Keyboard controller (K
The BC) 5 controls key input from a keyboard 9 or a pointing device such as a mouse. The CRT controller 6 controls display of image data on the CRT display 10.

The memory controller 7 controls access to an external memory 11 such as a hard disk or a floppy disk for storing a boot program, font data, user files, and the like. The printer controller 8 controls communication with the printer controller 4001 of the printer main body 4000.

The printer main body 4000 includes a CPU 12 and an R
AM 13, ROM 14, input unit 16, printing unit I / F1
7, a memory controller (MC) 18, a printing unit 20, an external memory 21, and an operation unit 4012.

The CPU 12 controls various devices connected to the system bus 15 and controls the printing unit 20 connected via the printing unit interface 17 according to various program steps such as an image processing program and a control program stored in the ROM 14. Outputs image data. Also,
Communication processing with the host computer is enabled via the input unit 16, and information on the printer, such as out of paper, can be notified to the host computer 5000.

The RAM 13 is a storage unit used as a main memory or a work area of the CPU 12, and the memory capacity can be expanded by installing an optional RAM card. Further, it is also used as an area for expanding input image data sent from the host computer and an area for storing environmental data such as printer mode setting information. The ROM 14 stores the program steps of the image processing shown in the flowchart of FIG. Also, font data and the like used when performing the image processing are stored.

A memory controller (MC) 18 controls access to a hard disk for storing a boot program, font data, user files, and the like, or an external memory 21 such as an IC card. The external memory 21 is not limited to one, and includes at least one or more,
A plurality of external memories storing a program for interpreting an optional font card and a printer control language in addition to the built-in fonts may be connected. Further, an NVRAM may be provided to store printer mode setting information from the operation panel 4012.

The operation panel 4012 includes switches for operating the printer by a user, an LED display, and the like. The interface 23 is connected to the printer controller 8 of the host computer 5000 and the printer main body 4.
000 printer controller 4001.

FIG. 6 is a flowchart for explaining a process for controlling the printer device according to one embodiment of the present invention.

Here, as a criterion (threshold) for determining the resolution of the image object included in the input image data, for example, a half value of the resolution of the printer is set in advance as a threshold, and the resolution of the image object is set. Is the threshold (in this embodiment, 300 dpi)
The above is defined as high resolution, and those below it are defined as low resolution. The threshold value is not limited to this, and may be set by the user from the printer driver, and may be stored in the RAM 13 of the printer main body 4000 or may be stored in the ROM 14 of the printer main body 4000 in advance. .

In step 601, the internal memory and various I
The printer device performs initialization such as / O and enters a standby state. In step 602, it is determined whether or not the input image data sent from the host computer is stored in the page buffer area of the RAM 13 in FIG. 5, and if the page buffer area contains the output information, step 60
Go to step 3; otherwise, continue monitoring the page buffer area. The input image data sent from the host computer includes, for example, a header portion and a data portion including information such as the size and resolution of the image of the input image data.

In step 603, the input image data stored in the page buffer area is analyzed. Step 60
In step 4, it is determined whether or not the input image data includes an image object based on the analysis result of step 603. If the input image data includes an image object, the process proceeds to step 605; otherwise, the process proceeds to step 609.

In step 605, the resolution of the image object included in the input image data is obtained and stored. If there are multiple image objects,
An ID is assigned to each image object. In step 606, the resolution criterion (threshold) of the image object such as a photograph included in the input image data is set to 30.
When the resolution of the image object is equal to or greater than the threshold value (the image object has a high resolution), the process proceeds to step 607. When the resolution of the image object is less than the threshold value (the image object has a low resolution), the process proceeds to step 608. In the present embodiment, one criterion for resolution is set. However, a plurality of criterions may be set, and the gradation processing method may be changed stepwise according to the resolution of each image object.

In step 607, gradation processing for high resolution is performed. In the present embodiment, an output image data image is created at 8 bits / pixel by the 200 dpi pulse width modulation method. In step 608, gradation processing for low resolution is performed. In this embodiment, an output image data image is created by a combination of the 600 dpi pulse width modulation method and the multi-level dither processing. Further, the gradation processing for high resolution and the gradation processing for low resolution may be a gradation processing method such as an error diffusion method.

In step 609, an output image data image is created for each color plane of CYMK by taking the procedure of creating an output image data image such as reading a normal font. In step 610, it is determined whether the output image data image has been created for one page. If the creation has not been completed, the process returns to step 603 to continue the process. Otherwise, the process proceeds to step 611.

In step 611, an output image data image for one page is output. At this time, step 605
An HRESO signal is generated based on the resolution information obtained in step (1), and the processing of the 200 dpi pulse width modulation method and the processing of the 600 dpi pulse width modulation method can be switched. In step 612, it is determined whether the output of the output image data image has been completed for all pages. If the output of the output image data image has been completed for all pages, the process returns to step 602 to continue the process. Otherwise, the process returns to step 603 to continue the process.

The image objects included in the input image data include image data having gradation, such as image data output from an image scanner or a digital still camera, in addition to photographs, graphic data, character data, and table data. Needless to say,

In the present embodiment, an image processing apparatus provided with a laser beam printer has been described as an example. However, the present invention is not limited to this. Needless to say, the present invention can be applied to a processing apparatus.

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. It goes without saying that the CPU provided in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0043]

As described above, according to the present invention, an image processing apparatus capable of performing gradation processing according to the resolution of an image object such as a photograph contained in input image data described in a page description language. , A method and a computer-readable storage medium used in the method.

[0044]

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a multilevel dither method according to an embodiment of the present invention;

FIG. 2 is a diagram showing a size of a region to be painted by one pixel by a 600 dpi pulse width modulation method according to an embodiment of the present invention;

FIG. 3 is a diagram for explaining the difference between the output results of the 200 dpi and 600 dpi pulse width modulation systems according to one embodiment of the present invention;

FIG. 4 is a diagram illustrating a configuration example of an image processing apparatus including a laser beam printer according to an embodiment of the present invention as a printer engine;

FIG. 5 is a block diagram illustrating a configuration example of a system of an image processing apparatus according to an exemplary embodiment of the present invention;

FIG. 6 is a flowchart illustrating a process of controlling the printer device according to the embodiment of the present invention.

Claims (7)

[Claims] An acquisition unit configured to acquire a resolution of an image object included in input image data described in a page description language; and a processing unit configured to perform a gradation process on the image object according to a resolution of the image object. An image processing apparatus comprising: 2. The image processing apparatus according to claim 1, wherein the obtaining unit obtains a resolution of the image object from header information of input image data described in the page description language. 3. The processing means compares the resolution of the image object with a predetermined threshold value, and if the resolution of the image object is greater than or equal to the threshold value, sets the resolution of the image object to high resolution. Performing high-resolution gradation processing on the image object, and, when the resolution of the image object is smaller than the threshold, setting the resolution of the image object to low resolution and performing low-resolution gradation processing on the image object. The image processing apparatus according to claim 1, wherein: 4. The gradation processing for high resolution is performed at 200d
The image processing apparatus according to claim 2, wherein the tone processing method is a pi pulse width modulation method, and the low-resolution gradation processing is a multi-value dither method. 5. The image processing apparatus according to claim 1, wherein the threshold can be set by a user. 6. An image processing apparatus comprising: acquiring a resolution of an image object included in input image data described in a page description language; and performing a gradation process on the image object according to the resolution of the image object. Method. 7. A computer readable storage medium storing a program code for image processing, wherein the program code is for obtaining a resolution of an image object included in input image data described in a page description language; Computer-readable storage medium comprising: a program code for performing a gradation process on the image object according to a resolution of the image object.