JPH11164127A - Image processor, and method and storage medium therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lines which are less than a prescribed width from being lost by thinning rows or columns in images for which pixels are disposed in a matrix form and reducing a data amount. SOLUTION: In steps S302-S304, whether or not the line in a horizontal direction less than the prescribed width is present is checked. When the straight line is not present ('No' in the step S302), a row thinning processing (processing for thinning one of two rows for instance) is executed in a step S305. When the straight line is present ('Yes' in the step S304), the row thinning processing is not executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus and method for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, and a memory medium for the processing.

[0002]

2. Description of the Related Art As a method of reducing the amount of image data, 1) a method of thinning out pixels from a two-dimensional image at a ratio of, for example, (n-1) rows to n (natural number of 2 or more) rows ( Hereinafter, the line thinning method), 2) From the two-dimensional image, m (2
A method of thinning out pixels at a ratio of, for example, (m-1) columns for the above (natural number) columns (hereinafter, column thinning method), 3) For example, (n-1) rows for n rows from a two-dimensional image And a method of thinning out pixels at a rate of, for example, (m-1) columns for m columns (hereinafter, a matrix thinning method). These pixel thinning methods have the advantage that the algorithm is simple but the effect of reducing the data amount is large.

[0003] In the following, processing by the row thinning method is referred to as row thinning processing, processing by the column thinning method is referred to as column thinning processing,
Processing by the matrix thinning method is called matrix thinning processing.

[0004]

However, when an image is processed by the above-described thinning method, for example, (n-1)
In some cases, a horizontal straight line less than the pixel width or a vertical straight line less than (m-1) pixel width may be lost, or the processed image may be different in color from the original image. Could not.

The present invention has been made in view of the above circumstances, and has as its object to reduce image quality deterioration due to pixel thinning.

[0006]

SUMMARY OF THE INVENTION An image processing apparatus according to the present invention is an image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein the horizontal width is smaller than a predetermined width. And / or detecting means for detecting a straight line in the vertical direction from the image, and when a horizontal and / or vertical straight line smaller than a predetermined width is not detected by the detecting means, a predetermined line and / or a predetermined line in the image is detected. Thinning means for thinning out the predetermined row and / or column by deleting pixels belonging to the column.

In the image processing apparatus according to the present invention, it is preferable that the thinning-out unit thins out a predetermined line in the image when the detecting unit does not detect a horizontal straight line narrower than a predetermined width.

In the image processing apparatus according to the present invention, it is preferable that the thinning-out unit thins out a predetermined column in the image when the detection unit does not detect a vertical straight line narrower than a predetermined width.

In the image processing apparatus according to the present invention, the thinning-out means may include a predetermined row and a predetermined column in the image when the detecting means does not detect any of horizontal and vertical straight lines smaller than a predetermined width. Is preferably thinned out.

In the image processing apparatus according to the present invention, it is preferable that the thinning means thins out rows and / or columns at a predetermined interval.

In the image processing apparatus according to the present invention, the thinning means thins out, for example, (n-1) rows with respect to n (natural number of 2 or more) rows.

In the image processing apparatus according to the present invention, the thinning-out unit thins out columns at a rate of (m-1) columns with respect to m (a natural number of 2 or more) columns, for example.

Another image processing apparatus according to the present invention is an image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, and forms a horizontal straight line narrower than a predetermined width. A detecting unit that detects from the image, and a line that thins out the predetermined line by deleting a pixel belonging to the predetermined line in the image when a horizontal straight line narrower than a predetermined width is not detected by the detecting unit. And a thinning means.

In another image processing apparatus according to the present invention, when a horizontal straight line narrower than a predetermined width is detected by the detection means, a pixel belonging to a predetermined column in the image is deleted. It is preferable to further include a row thinning unit for thinning out a predetermined row.

In another image processing apparatus according to the present invention,
It is preferable that the line thinning unit thins out lines at predetermined intervals.

In the image processing apparatus according to the present invention, the line thinning means thins out rows at a ratio of (n-1) rows to n (natural numbers of 2 or more) rows, for example.

In the image processing apparatus according to the present invention, it is preferable that the column thinning unit thins out columns at a ratio of (m-1) columns to m (a natural number of 2 or more) columns, for example.

Still another image processing method according to the present invention is an image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein the vertical straight line is narrower than a predetermined width. Detecting from the image, and when the detecting unit does not detect a vertical straight line narrower than a predetermined width, thinning out the predetermined column by deleting pixels belonging to a predetermined column in the image. Column thinning means.

Still another image processing apparatus according to the present invention is such that, when a vertical straight line smaller than a predetermined width is detected by the detection means, a pixel belonging to a predetermined row in the image is deleted. It is preferable that the apparatus further comprises a line thinning means for thinning the predetermined line.

In still another image processing apparatus according to the present invention, it is preferable that the column thinning means thins out columns at predetermined intervals.

In still another image processing apparatus according to the present invention, the column thinning means thins out columns at a ratio of (m-1) to m (natural numbers of 2 or more) columns, for example.

In still another image processing apparatus according to the present invention, the line thinning means thins out rows at a ratio of (n-1) rows to n (natural number of 2 or more) rows, for example.

It is preferable that each of the above-described image processing apparatuses according to the present invention further includes a compression unit that compresses an image obtained by thinning out pixels.

It is preferable that the image processing apparatus according to the present invention further includes a transfer unit that transfers the compressed image to the image output device.

It is preferable that each of the above-described image processing apparatuses according to the present invention further includes a transfer unit that transfers an image obtained by thinning out pixels to an image output apparatus.

An image processing method according to the present invention is an image processing method for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule.
Or a detection step of detecting a vertical straight line from the image,
When a horizontal and / or vertical straight line narrower than a predetermined width is not detected in the detection step, the pixels belonging to a predetermined row and / or column in the image are deleted to remove the predetermined row and / or column. And a thinning step of thinning out.

Another image processing method according to the present invention is an image processing method in which pixels in an image in which pixels are arranged in a matrix are thinned out according to a predetermined rule, and a horizontal straight line narrower than a predetermined width is drawn. A detection step of detecting from the image, and a line for thinning out the predetermined line by deleting pixels belonging to the predetermined line in the image when a horizontal straight line narrower than a predetermined width is not detected in the detection step. And a thinning step.

Still another image processing method according to the present invention is an image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein the vertical straight line is narrower than a predetermined width. In the image, and in the case where a vertical straight line smaller than a predetermined width is not detected in the detection step, the predetermined column is thinned out by deleting pixels belonging to a predetermined column in the image. And a column thinning step.

A memory medium according to the present invention is a memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule. Or a code of a detection step of detecting a vertical straight line from the image, and a predetermined line and / or a predetermined line in the image when a horizontal and / or vertical straight line narrower than a predetermined width is not detected in the detection step. And a code for a thinning-out step of thinning out the predetermined row and / or column by deleting pixels belonging to the column.

Another memory medium according to the present invention is a memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule,
A code for a detection step of detecting a horizontal straight line smaller than a predetermined width from an image, and belonging to a predetermined row in the image when a horizontal straight line smaller than a predetermined width is not detected in the detection step. And a code for a line thinning step of thinning out the predetermined line by deleting pixels.

Still another memory medium according to the present invention is a memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, and is smaller than a predetermined width. A code for a detection step of detecting a vertical straight line from an image, and when a vertical straight line smaller than a predetermined width is not detected in the detection step,
And a code for a column thinning-out step of thinning out the predetermined column by deleting pixels belonging to the predetermined column in the image.

The image processing device includes, for example, an information processing device such as a computer and an output device such as a printer.

[0033]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] In this embodiment,
Although the present invention relates to an example in which the present invention is applied to a printer system in which a laser beam printer and a computer are connected, the present invention is not limited to a system including a laser beam printer, but is also applicable to a system including an image output device of another system. It is.

FIG. 1 is a diagram showing a configuration of a laser beam printer according to a preferred embodiment of the present invention. The laser beam printer 1000 receives print information (for example, compressed image data), form information, macro instructions, and the like transmitted from a computer as an external device, and based on the information, records on a recording medium (for example, recording paper). ) To form an output image.

Reference numeral 1012 denotes an operation panel on which switches for the user to perform various operations and a display for displaying messages and setting contents are arranged. 1001
Is a printer control unit that controls various devices in the laser beam printer 1000. For example, the printer control unit decompresses compressed image data, converts the decompressed image data into a video signal, and supplies the video signal to the laser driver 1002. The laser driver 1002 is a circuit for driving the semiconductor laser 1003, and switches on / off of the semiconductor laser 1003 according to an input video signal.

A laser beam 1004 emitted from a semiconductor laser 1003 is swung right and left by a rotary polygon mirror 1005, thereby scanning and exposing the electrostatic drum 1006. By this scanning exposure, an electrostatic latent image is formed on the electrostatic drum 1006. This electrostatic latent image is transferred to the electrostatic drum 10
After the image is developed by a developing unit 1007 disposed around the sheet No. 06, the image is transferred to a recording sheet (cut sheet).

The recording paper is stored in a paper cassette 1008, and includes a paper feed roller 1009 and a transport roller 101.
It is taken into the apparatus by 0 and 1011 and supplied to the electrostatic drum 1006.

Further, the laser beam printer 1000
It has a card slot (not shown) and can be connected to, for example, an optional font card or a control card (emulation card) having a different language system.

FIG. 2 is a diagram showing a configuration of a printer system according to a preferred embodiment of the present invention. This printer system is, as described above, a laser beam printer 10.
00 and the host computer 3000 via the interface 21.

The host computer 3000 creates, for example, document information in which graphics, images, characters, tables, and the like are mixed based on a document processing program and the like stored in the program ROM 3b, and based on the document information by a printer driver. The apparatus includes a CPU 1 that controls processing for generating print information (including, for example, compressed image data) and transmitting the print information to the laser beam printer 1000.

The font ROM 3a stores character pattern data (font data).
Can generate print information by referring to the character pattern data. Also, the data ROM 3c
For example, various data for controlling the above-described document processing are stored. The RAM 2 functions as a work memory when the CPU 1 executes various processes.

The keyboard controller (KBC) 5
In addition to controlling the keyboard 9, a pointing device (not shown) is controlled, and input data from these devices is taken in.
A CRT controller (CRTC) 6 controls display on a CRT display 10. Memory controller (M
C) 7 stores a boot program, an application program, font data, a user file, an edit file, and the like.

The printer controller (PRTC) 8
Printer 10 via a bidirectional interface 21
00, a process for transmitting print information to the printer 1000 and a process for receiving control information are performed.

The CPU 1 executes processing for rasterizing the outline font data in a display image memory area provided in a predetermined area of the RAM 2 and processing for enabling WYSIWYG on the CRT 10, for example. Or run it. Further, the CPU 1 has a CRT 1
For example, based on a command indicated by a mouse cursor or the like displayed at 0, various windows are opened,
For example, execute the instructed information processing.

The printer 1000 has a program ROM 1
3b or print information supplied from the host computer 3000 based on the control program stored in the external memory 14, generates image data based on the print information, and outputs the image data via the print unit interface 16. And controls the processing for forming an output image by supplying the image to the printing unit 17.

The font ROM 13a stores character pattern data (font data) to be referred to when generating image data corresponding to a character code included in print information. The data ROM 13c stores data for controlling various processes.

The CPU 12 can communicate with the host computer 3000 via the input unit 18. For example, the CPU 12 receives print information from the host computer 3000, and also sends control information (for example, status information) to the host computer 3000. Can be sent.

The RAM 19 has a work area for the CPU 12, a development area for image data, a storage area for environmental data, and the like. The external memory 14 is connected as an option, and provides the CPU 12 with, for example, font data, emulation data, form data, and the like. Access to the external memory 14 is controlled by a memory controller 20. The operation unit 18 includes the above-described operation panel and forms a user interface.

In this embodiment, the host computer 3000 generates print information including image data. Here, the host computer 3000 may generate print information in the form of image data for the entire page, or may set the image data format only for an image (for example, an image captured by a scanner), Part (for example,
With respect to images such as characters and line drawings, print information in a page description language or other code information format may be generated. In the following, a description will be given assuming that the host computer 3000 generates print information in the form of image data for the entire page.

The host computer 3000 generates image information of an image appropriately including characters, line drawings, images, and the like based on a document processing program or the like, and then, based on the image information based on an instruction from a user, for example. Then, print information is generated and supplied to the printer 1000. In this embodiment, first, image data is generated (developed) based on the image information, and then, the image information is subjected to a pixel thinning process as appropriate and then subjected to a compression process to generate print information. I do.

As described above, in the present embodiment, pixel thinning processing and compression processing are executed on the host computer 3000 side. However, the present invention is not limited to this. For example, pixel thinning processing from the host computer 3000 is performed. The present invention can also be applied to a case where print information that is not subjected to processing or compression processing is supplied to the printer 1000 and, for example, thinning processing or compression processing is executed when this print information is temporarily stored in the printer 1000.

When the printer 1000 forms an output image based on print information on which pixel thinning processing and compression processing have been performed, it goes without saying that the print information is subjected to expansion processing and pixel interpolation processing. No.

In the following, the JPEG system is used for the compression processing of image data in, for example, a YUV (Y: lightness, U / V: color difference component) color space. Will be described.

FIG. 3 is a flowchart showing the flow of print information generation processing in the host computer 3000. The processing shown in this flowchart can be controlled based on, for example, a control program stored in the program ROM 3b, but the control program can also be provided by the external memory 11.

The process shown in FIG. 3 is started after image data to be printed is generated based on a print instruction. First, in step S301, image data is acquired from the image data generation program.

In step S302, step S301
Step S for all areas related to the image data acquired in
It is checked whether or not the check in 304 has been performed. If the check has been completed for all areas, the process proceeds to step S305, and if there is an unchecked area, the process proceeds to step S303.

In step S303, step S304
Use to determine the area to be investigated. Step S30
In step 4, it is checked whether or not a horizontal line having a predetermined width (for example, one pixel width) or less exists in the region to be determined determined in step S303. If the straight line does not exist, the process returns to step S302. Thus, step S
Unless it is determined to be “Yes” in 304, it is checked in step S303 whether or not there is a horizontal straight line having a predetermined width or less in all the areas while sequentially changing the area to be checked.

Here, as a method of examining a horizontal straight line, for example, while sequentially changing the pixel of interest, the pixel value of the pixel of interest is compared with the pixel value of the left or right pixel of the pixel of interest. A method of forming a binary image in which the values match "1" when they match and "0" when they do not match, and investigate the width of the image having the pixel value "1" in the binary image. is there.

If it is determined in step S302 that the processing in step S304 has been completed for all areas ("No" in S302), it means that there is no horizontal straight line having a width equal to or less than a predetermined width. in this case,
In step S305, a line thinning process (for example, 2
Then, in step S306, a compression process (for example, compression by the JPEG method) is performed on the image data after the row thinning process, and a series of processes is completed. I do. As a result, print information is generated.

On the other hand, if it is determined in step S304 that there is a horizontal straight line having a width equal to or less than the predetermined width in the area to be investigated, in step S306, the image data acquired in step S301 is subjected to compression processing. A series of processing ends. As a result, print information is generated.

When the processing shown in FIG. 3 is completed, the host computer 3000 adds information indicating whether or not line thinning processing has been performed to the generated print information, and uses this as final print information. The data is transmitted to the printer 1000.

As described above, when there is no horizontal straight line having a width equal to or less than the predetermined width in the image to be printed, the data amount is reduced by executing the line thinning process. When a horizontal line having a width equal to or less than a predetermined width exists, the line thinning process is not performed, so that the loss of the horizontal line having a width equal to or less than the predetermined width or a change in color can be avoided.

[Second Embodiment] In this embodiment,
This is to change the print information generation processing in the host computer 3000 according to the first embodiment. Note that items not mentioned in this embodiment are the same as those in the first embodiment.

FIG. 4 is a flowchart showing a flow of print information generation processing in the host computer 3000 according to the second embodiment. The first embodiment determines whether or not to execute the line thinning process according to the image to be printed. However, the second embodiment determines the column thinning process according to the image to be printed. Is determined.

The process shown in FIG. 4 is started after image data to be printed is generated based on a print instruction. First, in step S401, image data is acquired from an image data generation program.

In step S402, step S401
Step S for all areas related to the image data acquired in
It is checked whether or not the check in 404 has been executed. If the check has been completed for all areas, the process proceeds to step S405, and if there is an unchecked area, the process proceeds to step S403.

In step S403, step S404
Use to determine the area to be investigated. Step S40
In step 4, it is checked whether or not a vertical line having a predetermined width (for example, one pixel width) or less exists in the region to be checked determined in step S403. If the straight line does not exist, the process returns to step S402. Thus, step S
Unless it is determined as “Yes” in 404, it is checked in step S403 whether or not there is a vertical straight line having a predetermined width or less in all the areas while sequentially changing the area to be checked.

Here, as a method of examining a straight line in the vertical direction, for example, for example, while sequentially changing the pixel of interest, the pixel value of the pixel of interest is compared with the pixel value of the pixel below or above the pixel of interest. Then, a binary image is formed in which "1" is set when both match, and "0" is set when they do not match.
There is a method of examining the width of the image having the pixel value “1” in the value image.

If it is determined in step S402 that the processing in step S404 has been completed for all the areas ("No" in S402), it means that there is no vertical straight line having a width equal to or smaller than the predetermined width. in this case,
In step S405, a column thinning process (for example, 2
Then, in step S406, the image data subjected to the column thinning process is subjected to a compression process (for example, compression by the JPEG method), and a series of processes is completed. I do. As a result, print information is generated.

On the other hand, if it is determined in step S404 that there is a vertical straight line having a width equal to or less than the predetermined width in the area to be investigated, in step S406, the image data acquired in step S401 is subjected to compression processing. A series of processing ends. As a result, print information is generated.

When the processing shown in FIG. 4 is completed, host computer 3000 adds information indicating whether or not the generated print information has been subjected to the column and row thinning processing, and uses this as final print information. The data is transmitted to the printer 1000.

As described above, when there is no vertical straight line having a width equal to or less than the predetermined width in the image to be printed, the data amount is reduced by executing the column thinning process. When a vertical straight line having a width equal to or less than a predetermined width exists, by not performing the column thinning process, it is possible to prevent the vertical line having a width equal to or less than the predetermined width from being lost or changed in color.

[Third Embodiment] In this embodiment,
This is to change the print information generation processing in the host computer 3000 according to the first embodiment. Note that items not mentioned in this embodiment are the same as those in the first embodiment.

FIG. 5 is a flowchart showing the flow of print information generation processing in the host computer 3000 according to the third embodiment. In this embodiment, when there is a horizontal straight line having a width equal to or less than a predetermined width, a column thinning process is executed. When there is no horizontal straight line having a predetermined width or less, a row thinning process is executed. .

The process shown in FIG. 5 is started after image data to be printed is generated based on a print instruction. First, in step S501, image data is acquired from the image data generation program.

In step S502, step S501
Step S for all areas related to the image data acquired in
It is checked whether or not the check in step 504 has been executed. If the check has been completed for all the areas, the process proceeds to step S507, and if an unchecked area remains, the process proceeds to step S503.

In step S503, step S504
Use to determine the area to be investigated. Step S50
In step 4, it is checked whether or not a horizontal line having a predetermined width (for example, one pixel width) or less exists in the region to be checked determined in step S503. If the straight line exists, step S505 is performed. If the straight line does not exist, the process returns to step S502. Thus, step S
Unless it is determined to be “Yes” in 504, it is checked in step S 503 whether or not there is a horizontal straight line having a predetermined width or less in all the areas while sequentially changing the area to be checked.

If it is determined in step S502 that the processing in step S504 has been completed for all areas ("No" in S502), it means that there is no horizontal straight line having a width equal to or smaller than the predetermined width. in this case,
In step S505, a line thinning process (for example, 2
Then, in step S506, a compression process (for example, compression by the JPEG method) is performed on the image data after the row thinning process, and a series of processes is completed. I do. As a result, print information is generated.

On the other hand, if it is determined in step S504 that a horizontal straight line having a width equal to or less than the predetermined width exists in the area to be examined, in step S505, a column thinning process (for example, a process of thinning one column out of two columns) ), And then, in step S506, a compression process (for example, J
(Compression according to the PEG method), and a series of processing ends. As a result, print information is generated.

When the processing shown in FIG. 5 is completed, the host computer 3000 adds information indicating whether the generated print information has been subjected to the row thinning processing or the column thinning processing, and finally adds the information. The print information is transmitted to the printer 1000 as appropriate print information.

As described above, when there is no horizontal straight line having a width equal to or smaller than a predetermined width in the image to be printed, the data amount is reduced by executing the line thinning process. When there is a horizontal straight line having a width equal to or less than a predetermined width, the data amount can be reduced while executing the column thinning process to prevent the horizontal straight line from being lost or changed in color. .

[Fourth Embodiment] In this embodiment,
This is to change the print information generation processing in the host computer 3000 according to the first embodiment. Note that items not mentioned in this embodiment are the same as those in the first embodiment.

FIG. 6 is a flowchart showing the flow of print information generation processing in the host computer 3000 according to the fourth embodiment. In this embodiment, when there is a vertical straight line having a width equal to or less than a predetermined width, a row thinning process is performed. When there is no vertical straight line having a predetermined width or less, a column thinning process is performed. .

The process shown in FIG. 6 is started after image data to be printed is generated based on a print instruction. First, in step S601, image data is acquired from a program for generating image data.

In step S602, step S601
Step S for all areas related to the image data acquired in
It is checked whether or not the check in step 604 has been executed. If the check has been completed for all areas, the process proceeds to step S607, and if there is an unchecked area, the process proceeds to step S603.

In step S603, step S604
Use to determine the area to be investigated. Step S60
In step 4, it is checked whether or not a vertical line having a predetermined width (for example, one pixel width) or less exists in the region to be checked determined in step S603. If the straight line exists, step S605 is performed. If the straight line does not exist, the process returns to step S602. Thus, step S
Unless it is determined to be “Yes” in 604, it is checked in step S603 whether or not there is a vertical straight line having a predetermined width or less in all the areas while sequentially changing the area to be checked.

If it is determined in step S602 that the processing in step S604 has been completed for all the regions ("No" in S602), it means that there is no vertical straight line having a width equal to or smaller than the predetermined width. in this case,
In step S605, a column thinning process (for example, 2
Then, in step S606, the image data subjected to the column thinning processing is subjected to compression processing (for example, compression by the JPEG method), and a series of processing ends. I do. As a result, print information is generated.

On the other hand, if it is determined in step S604 that a horizontal straight line having a width equal to or less than a predetermined width exists in the area to be investigated, in step S605, a line thinning process (for example, a process of thinning one of two lines) is performed. ), And then in step S606, a compression process (for example, J
(Compression according to the PEG method), and a series of processing ends. As a result, print information is generated.

When the processing shown in FIG. 6 is completed, the host computer 3000 adds information indicating whether the generated print information has been subjected to the row thinning processing or the column thinning processing, and finally adds the information. The print information is transmitted to the printer 1000 as appropriate print information.

As described above, when there is no vertical straight line having a width equal to or smaller than the predetermined width in the image to be printed, the data amount is reduced by executing the column thinning process. When there is a vertical straight line having a width equal to or less than a predetermined width, the data amount can be reduced while executing the line thinning process to prevent the vertical straight line from being lost or changing its color. .

[Fifth Embodiment] In this embodiment,
This is to change the print information generation processing in the host computer 3000 according to the first embodiment. Note that items not mentioned in this embodiment are the same as those in the first embodiment.

FIG. 7 is a flowchart showing the flow of print information generation processing in the host computer 3000 according to the fifth embodiment. In this embodiment, when there is a horizontal or vertical straight line having a width equal to or smaller than a predetermined width, a matrix thinning process (for example, a process of thinning out one row out of two rows and one out of two columns) is executed. If neither horizontal nor vertical straight line having a width equal to or smaller than the predetermined width exists, the matrix thinning process is executed.

FIG. 7 is a flowchart showing the flow of print information generation processing in the host computer 3000.

The process shown in FIG. 7 is started after image data to be printed is generated based on a print instruction. First, in step S701, image data is acquired from the image data generation program.

In step S702, step S701
Step S for all areas related to the image data acquired in
It is checked whether or not the check in 704 has been executed. If the check has been completed for all the areas, the process proceeds to step S705. If the unchecked area remains, the process proceeds to step S703.

In step S703, step S704
Use to determine the area to be investigated. Step S70
In step S4, it is determined whether there is a horizontal straight line having a width equal to or smaller than a predetermined width (for example, one pixel width) in the region to be investigated determined in step S703, and whether the predetermined width (for example, one pixel width) exists.
It is checked whether or not the following vertical straight line exists. If any horizontal or vertical straight line having the predetermined width or less exists, the process proceeds to step S706. Returns to step S702. In this way, unless it is determined to be “Yes” in step S704, it is determined whether or not there are horizontal and vertical straight lines having a predetermined width or less in all the regions while sequentially changing the region to be investigated in step S703. Is investigated.

If it is determined in step S702 that the processing in step S704 has been completed for all areas ("No" in S702), it is determined that there is no horizontal or vertical straight line having a width equal to or less than the predetermined width. Means In this case, in step S705, a matrix thinning process (for example, one row out of two
Then, in step S706, compression processing (for example, compression by the JPEG method) is performed on the image data that has been subjected to the matrix decimation processing, and a series of processing ends. I do. As a result, print information is generated.

On the other hand, if it is determined in step S704 that any of a horizontal line and a vertical line having a width equal to or less than the predetermined width exists in the area to be examined, the process proceeds to step S7.
In 06, the image data acquired in step S701 is subjected to compression processing, and a series of processing ends. As a result, print information is generated.

When the processing shown in FIG. 7 is completed, host computer 3000 adds information indicating whether or not a matrix thinning process has been performed to the generated print information, and uses this as final print information. The data is transmitted to the printer 1000.

As described above, when there is no horizontal or vertical straight line having a predetermined width or less in the image to be printed, the data amount is reduced by executing the matrix thinning process. If any horizontal or vertical straight line having a width equal to or less than a predetermined width exists in the target image, the horizontal and / or vertical lines having a width equal to or less than the predetermined width are lost by not executing the matrix thinning process. A change in color can be avoided.

In step S705, a row thinning process or a column thinning process may be executed instead of the matrix thinning process.

If there is no horizontal or vertical line having a width equal to or less than the predetermined width, matrix thinning processing is executed. If only a horizontal line having a width equal to or less than the predetermined width exists, column thinning is performed. Executes the processing, and if only vertical straight lines having a width equal to or less than a predetermined width exist, executes line thinning processing. If both horizontal and vertical straight lines having a width equal to or less than a predetermined width exist, performs line thinning. None of the processing, the column thinning processing, and the matrix thinning processing may be executed.

[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 including a single device can be used. (For example, a copying machine, a 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 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 novel function of the present invention, 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 included 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.

[0110]

According to the present invention, it is possible to reduce deterioration in image quality due to pixel thinning.

[0111]

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a laser beam printer according to a preferred embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a printer system according to a preferred embodiment of the present invention.

FIG. 3 is a flowchart illustrating a flow of print information generation processing in the host computer according to the first embodiment.

FIG. 4 is a flowchart illustrating a flow of print information generation processing in a host computer according to a second embodiment.

FIG. 5 is a flowchart illustrating a flow of print information generation processing in a host computer according to a third embodiment.

FIG. 6 is a flowchart illustrating a flow of print information generation processing in a host computer according to a fourth embodiment.

FIG. 7 is a flowchart illustrating a flow of print information generation processing in a host computer according to a fifth embodiment.

Claims (26)

[Claims] 1. An image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a horizontal and / or vertical straight line narrower than a predetermined width is detected from the image. Detecting means for detecting a horizontal and / or vertical straight line narrower than a predetermined width by deleting pixels belonging to a predetermined row and / or column in the image; And / or a thinning unit for thinning out rows. 2. The image according to claim 1, wherein the thinning-out unit thins out a predetermined line in the image when a horizontal line narrower than a predetermined width is not detected by the detection unit. Processing equipment. 3. The image according to claim 1, wherein the thinning-out unit thins out a predetermined column in the image when a vertical straight line smaller than a predetermined width is not detected by the detection unit. Processing equipment. 4. The method according to claim 1, wherein the thinning-out unit thins out predetermined rows and columns in the image when the detecting unit does not detect any of horizontal and vertical straight lines smaller than a predetermined width. The image processing device according to claim 1. 5. The image processing apparatus according to claim 1, wherein the thinning unit thins out rows and / or columns at predetermined intervals. 6. The image processing apparatus according to claim 1, wherein the thinning-out unit thins out rows at a rate of (n−1) rows to n (a natural number of 2 or more) rows. 7. The image processing apparatus according to claim 1, wherein the thinning-out unit thins out columns at a ratio of (m−1) columns to m (natural numbers of 2 or more) columns. 8. An image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a detecting means for detecting a horizontal straight line narrower than a predetermined width from the image, When the detection unit does not detect a horizontal straight line narrower than a predetermined width, a line thinning unit that thins out the predetermined line by deleting pixels belonging to the predetermined line in the image. Image processing apparatus. 9. A column thinning means for thinning out a predetermined column by deleting pixels belonging to a predetermined column in an image when a horizontal straight line narrower than a predetermined width is detected by the detecting means. The image processing apparatus according to claim 9, further comprising: 10. The image processing apparatus according to claim 8, wherein said line thinning means thins out lines at predetermined intervals. 11. The image processing apparatus according to claim 8, wherein the line thinning unit thins out rows at a ratio of (n-1) rows to n (natural numbers of 2 or more) rows. 12. The image processing apparatus according to claim 9, wherein the column thinning unit thins out columns at a ratio of (m-1) columns to m (a natural number of 2 or more) columns. 13. An image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a detecting means for detecting a vertical straight line smaller than a predetermined width from the image, When the detection unit does not detect a vertical straight line narrower than a predetermined width, a column thinning unit that thins out the predetermined column by deleting pixels belonging to a predetermined column in the image. Image processing apparatus. 14. A line thinning means for thinning out a predetermined line by deleting pixels belonging to a predetermined line in an image when a vertical line narrower than a predetermined width is detected by the detection means. 2. The method according to claim 1, further comprising:
4. The image processing device according to 3. 15. The image processing apparatus according to claim 13, wherein said column thinning means thins out columns at predetermined intervals. 16. The image processing apparatus according to claim 13, wherein the column thinning unit thins out columns at a rate of (m−1) with respect to m (a natural number of 2 or more) columns. 17. The image processing apparatus according to claim 14, wherein the line thinning unit thins out rows at a ratio of (n-1) rows to n (natural numbers of 2 or more) rows. 18. The apparatus according to claim 1, further comprising compression means for compressing an image in which pixels are thinned out.
8. The image processing device according to any one of items 7 to 7. 19. The image processing apparatus according to claim 18, further comprising a transfer unit configured to transfer the compressed image to an image output device. 20. The image processing apparatus according to claim 1, further comprising a transfer unit configured to transfer an image in which pixels have been thinned out to an image output device. 21. An image processing method for thinning out pixels in an image in which pixels are arranged in a matrix according to a predetermined rule, wherein a horizontal and / or vertical straight line narrower than a predetermined width is detected from the image. A detection step, and in a case where a horizontal and / or vertical line narrower than a predetermined width is not detected in the detection step, a pixel belonging to a predetermined row and / or column in the image is deleted to remove the predetermined row. And / or a thinning step of thinning out rows. 22. An image processing method for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a detection step of detecting a horizontal straight line smaller than a predetermined width from the image, A line thinning step of thinning out the predetermined row by deleting pixels belonging to a predetermined row in the image when a horizontal straight line narrower than a predetermined width is not detected in the detection step. Image processing method. 23. An image processing apparatus for thinning out pixels in an image in which pixels are arranged in a matrix according to a predetermined rule, wherein a detection step of detecting a vertical straight line smaller than a predetermined width from the image, A column thinning step of thinning out the predetermined column by deleting pixels belonging to the predetermined column in the image when a vertical straight line narrower than a predetermined width is not detected in the detection step. Image processing method. 24. A memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a horizontal and / or vertical straight line narrower than a predetermined width is formed. A code of a detection step for detecting from the image, and deleting pixels belonging to a predetermined row and / or column in the image when a horizontal and / or vertical straight line narrower than a predetermined width is not detected in the detection step. A code for a thinning-out step for thinning out the predetermined row and / or column. 25. A memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a horizontal straight line narrower than a predetermined width is detected from the image. A code of a detection step to be performed, and a line thinning step of thinning out the predetermined row by deleting pixels belonging to a predetermined row in an image when a horizontal straight line narrower than a predetermined width is not detected in the detection step. A memory medium characterized by comprising: and a code. 26. A memory medium storing an image processing program for thinning out pixels in an image in which pixels are arranged in a matrix in accordance with a predetermined rule, wherein a vertical straight line narrower than a predetermined width is detected from the image. A code of a detection step to be performed, and a column thinning step of thinning out the predetermined column by deleting pixels belonging to a predetermined column in an image when a vertical straight line smaller than a predetermined width is not detected in the detection step. A memory medium characterized by comprising: and a code.