JPH11232447A - Image reduction method and image display device using the reduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reduction method which can reduce an image including a high frequency component or an image consisting of a single pixel unit with no blur nor disappearance of the outline or lines of the image. SOLUTION: This image display device comprises a TV signal encoder 3 which converts the picture images into the TV signals, an image storage means 2 which stores the picture images that are shown on a TV monitor 4, a transfer control means 5 which transfers the images stored in the means 2 to the encoder 3 as the 1st and 2nd field images of a TV signal interlace system, an image reduction means 101 which reduces an image to be displayed into half (by using a reference pixel that is adjacent to two pixels adjacent to each other in the same direction, using the pixels of different colors if one of two pixels has the same color as that of the reference pixel and using a pixel that has a mean color of two pixels as a reduced pixel if both pixels have no identical color as that of the reference pixel), and an image transfer means 103 which transfers the reduced pixel to the means 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for reducing the size of an image displayed on a screen of an information processing apparatus such as a personal computer, and an image displayed on the screen of an information processing apparatus such as a personal computer using the method. The present invention relates to an image display method and an image display device for displaying the image on a monitor such as a television.

[0002]

2. Description of the Related Art Current monitors such as televisions display images in an interlaced (interlaced scanning) system based on input television signals. In the interlace method, an image for one screen is composed of the first field and the second field.
It consists of two fields. FIG.
FIG. 2 is a diagram illustrating a method of displaying an image by an interlace method on a monitor such as a television. FIG.
, The screen 900 of the television includes two field images of a first field 920 and a second field 930. The first field 920 is
The second field 930 includes scanning lines (lines) 901 to 908, and the second field 930 includes scanning lines 911 to 918. An image for one screen is displayed by alternately displaying the images of these fields line by line.

On the other hand, a so-called television signal encoder for converting an image image in an information processing device such as a personal computer into a television signal is known. According to this, the first field image and the second field image for the image to be displayed such as the image displayed on the screen of the information processing device are stored in the memory, and each image is designated by the television signal encoder. By transferring to the television signal encoder at the timing, it is possible to display the image on a monitor of a television or the like in an interlaced manner.

On the other hand, Japanese Patent Application Laid-Open No. 6-124189 discloses a method for reducing an image. According to this method, when the image is reduced in half in the vertical direction, the image can be efficiently reduced by taking the average of two lines or taking one of the two lines.

[0005]

In order to display an image to be displayed, such as an image displayed on an information processing apparatus, on a monitor such as a television by the above-described technique, the images in the first field and the second field must be displayed. Each of them needs to be stored in a memory, and there is a problem that a large amount of memory is wasted. Therefore, as shown in FIG. 13, paying attention to the fact that the images of the first field and the second field are almost the same, the image to be displayed is reduced in half in the vertical direction, and this image is reduced to the first field. And an image display device capable of displaying an image to be displayed, such as an image displayed on an information processing device, on a monitor such as a television by a simple control with a small amount of memory by using the same as the image of the second field. Is the first object.

Further, as described above, when an image to be displayed is reduced to one half in the vertical direction, Japanese Patent Laid-Open No.
No problem occurs when the image to be displayed does not contain a high-frequency component such as a natural image when using the method described in Japanese Patent Application Laid-Open Publication No. H11-27139. When displaying an image composed of the following, there is a problem that outlines and lines are blurred or disappear and become invisible. It is a second object of the present invention to provide an image reduction method capable of reducing an image including a high frequency component or an image composed of one pixel, such as a presentation image, without blurring or disappearing outlines and lines. .

Further, by applying the image reduction method for achieving the second object to an image display device for achieving the first object, the image can be constituted by an image containing a high-frequency component such as a presentation image or by one pixel. It is a third object of the present invention to provide an image display device in which an outline or a line of an image is not blurred or disappeared.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method of reducing an image by using two adjacent images.
When generating one pixel for each pixel, one pixel adjacent to the two pixels in the same direction is set as a reference pixel, and among the two pixels, a pixel having the same color as the one pixel (reference pixel) exists. In this case, pixels having different colors are adopted, and
If there is no pixel having the same color as the one pixel (reference pixel), a pixel having an average color of the two pixels is generated and reduced to one pixel.

Further, in order to solve the above-mentioned problems and achieve the object of the present invention, the present invention provides an image display device with the following means. That is, in order to achieve the first object of the present invention, an image display device according to the present invention includes at least a television signal encoding unit for converting an image in an information processing device into a television signal, and a monitor such as a television. An image storage means for storing an image in the information processing apparatus to be displayed, and the image signal stored in the image storage means as an image of a first field and a second field in an interlace system of a television signal. Transfer control means for transferring, an image to be displayed in the information processing apparatus, image reducing means for reducing the image in half in the vertical direction, and transferring the reduced image to the image storage means And an image transfer means.

The operation of each of the above means will be described below. First, the image reducing unit acquires an image to be displayed in the information processing apparatus, reduces the image vertically by half, and transfers the reduced image to the image storage unit. Next, the transfer control means stores the image stored in the image storage means in the first field and the second field in response to the request for the first field video and the second field video issued by the television signal encoding means. The image is transferred to a television signal encoding unit, converted into a television signal by the television signal encoding unit, and displayed on a monitor such as a television. At this time,
An image display device in which the television signal encoding means displays the images of the first field and the second field on the same line on the television monitor, that is, the image is displayed every other line on the display screen of the monitor is also conceivable. Thereby, flicker can be suppressed.

Further, in order to achieve the second and third objects of the present invention, the image reducing method according to the present invention provides a method for generating one pixel for two adjacent pixels. Further, one pixel adjacent in the same direction is used as a reference pixel, and when a pixel of the same color as the one pixel (reference pixel) is present among the two pixels, a pixel having a different color is adopted. When there is no pixel having the same color as the one pixel (reference pixel) among the pixels, a pixel having an average color of the two pixels is generated and reduced. As a result, in an image including a high frequency component or an image composed of one pixel, such as a presentation image,
The contours and lines can be reduced without blurring or disappearing and disappearing.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a hardware configuration of an information processing apparatus such as a personal computer to which an image reduction method according to the present invention and an image display apparatus using the same can be applied, and functional blocks executed by a central processing unit. As shown in FIG. 1, the image display device according to the present invention includes a personal computer 1, a frame memory 2, a transfer control device 5, a television signal encoding device 3, and a television image display device 4. Is done.

The personal computer 1 includes a central processing unit 10, a main memory 11, an auxiliary storage device 3, a PC image display device 13, a PC display memory 14, and an input device 15. The components other than the PC image display device 13 and the transfer control device 5, and the television signal encoding device 3 and the television image display device 4 are connected by a bus 16 so that necessary information can be transmitted between the components. Have been.

The central processing unit 10 includes an image reduction unit 101
, A control unit 102, and an image transfer unit 103.

The frame memory 2 corresponds to image storage means, and stores an image of an information processing device to be displayed on the television image display device 4. This frame memory 2
For example, it can be realized by a random access memory (RAM) or the like. In particular, since the image stored in the frame memory 2 is used as both the image of the first field and the image of the second field, it is sufficient that the image has a capacity enough to store at most one of the images.

The television image display device 4 is a monitor of a television or the like, and is connected to the television signal encoding device 3.
Accordingly, the image display device according to the present invention can acquire and display an image converted into a television signal by the television signal encoding device 3.

The television signal encoding device 3 corresponds to television signal encoding means, and a known television signal encoder can be applied. The television signal encoding device 3 is connected to the transfer control device 5 and converts the image stored in the frame memory 2 and transmitted by the transfer control device 5 into a television signal. As a result, it is possible to generate the image signals of the first field and the second field with respect to the image stored in the frame memory 2 and display them on the television image display device 4 in an interlaced system. At this time, the images of the first field and the second field are displayed on the same line on the television image display device 4.
That is, the television signal encoding device 3 configured to be displayed every other line on the display screen of the television image display device 4 may be used. Thereby, flicker can be suppressed.

The transfer control device 5 corresponds to a transfer control means, is connected to the television signal encoding device 3 and the frame memory 2, and responds to a request for an image in the first field or the second field issued by the television signal encoding device 3. On the other hand, image data is transferred from the frame memory 2 to the television signal encoding device 3.

The PC display memory 14 is realized by a random access memory (RAM), for example, and stores an image of an image to be displayed on the PC image display device 13. The image display device according to the embodiment of the present invention can acquire an image to be displayed in the information processing device by acquiring an image image from the PC display memory 14.

The PC image display device 13 is, for example, a CRT,
A monitor in an information processing device such as a personal computer realized by an EL display or a liquid crystal display.
The image stored in the display memory 14 can be displayed.

The main memory 11 is a means for functioning as a work area and for storing a program for defining an operation procedure of the central processing unit 10 and data to be processed by the central processing unit 10. (RAM), read only memory (ROM), and the like.

The auxiliary storage device 12 is a means for storing a program for controlling the operation of the device, data necessary for the operation, and the like, and is realized by a floppy disk, a hard disk, a memory card, or the like.

The input device 15 is a means for inputting necessary commands and information, and is realized by, for example, a keyboard or a pointing device such as a mouse. The user of the present apparatus can issue an instruction to start or end the image display apparatus through the input device 15.

The central processing unit 10 is mainly composed of a microprocessor, and performs a predetermined operation according to a program stored in the main memory 11 or the auxiliary storage device 12 in advance. In particular, in the image display device according to the embodiment of the present invention, the image reduction unit 101 which is a program stored in the main memory 11 or the auxiliary storage device 12 in advance,
The processing of the image transfer unit 103 and the control unit 102 is executed.

Here, the image reducing unit 101 corresponds to an image reducing unit, and obtains an image to be displayed on the PC image display device 13 by obtaining an image from the PC display memory 14 and vertically converts the image. In the horizontal direction.

The image transfer unit 103 corresponds to an image transfer unit, and transfers the image reduced by the image reduction unit 101 to the frame memory 2.

Further, the control section 102 controls each of the above sections.

That is, in the image display device according to the embodiment of the present invention, the central processing unit 10 controls the image reduction unit 101 and the image transfer unit 10 under the control of the control unit 102.
3, a PC display memory 14, a main memory 11 or an auxiliary storage device 12, a frame memory 2, a transfer control device 5,
The image displayed on the PC image display device 13 is displayed on the television image display device 4 in cooperation with the television signal encoding device 3 and the like.

Next, the relationship between the above-described hardware configuration and each functional block executed by the central processing unit 10 will be described with reference to FIG. In FIG. 2, an information processing device such as a personal computer displays an image stored in a PC display memory 14 on a PC image display device 13.

When the user instructs activation of the image display device by the input device 15, the control unit 102 is activated in the central processing unit 10 and the following processing is repeated. That is, first, the image reducing unit 101 corresponding to the image reducing unit
Is started, an image to be displayed in the information processing apparatus is obtained by obtaining an image from the PC display memory 14, and the image is reduced in the vertical direction by half, and It is stored in the device 12.

Next, the image transfer unit 103 corresponding to the image transfer unit is started, the reduced image is obtained from the main memory 11 or the auxiliary storage device 12, and transferred to the frame memory 2 corresponding to the image storage unit. .

On the other hand, the transfer control device 5 corresponding to the transfer control means responds to the request for the image of the first field or the second field issued by the television signal encoding device 3 corresponding to the television signal encoding means, by the frame memory 2. , And transfers the image data to the television signal encoding device 3. The television signal encoding device 3 converts the transferred image image into a television signal and displays it on the television image display device 4. The television signal encoding device 3
The transfer control device 5 operates asynchronously with the control unit 102. That is, the television signal encoding device 3 issues a request for an image in the first field or the second field to be repeatedly displayed on the television image display device 4 to the transfer control device 5, and the transfer control device 5 , The image data stored in the frame memory 2 is transferred to the television signal encoding device 3.

Next, details of the processing contents of the control unit 102 will be described with reference to the drawings. FIG. 3 is a flowchart showing the processing contents of the control unit 102. A program for realizing this processing is stored in the main memory 11 or the auxiliary storage device 12, and is executed by the central processing unit 10. Also,
The control unit 102 is executed when the user instructs the input device 15 to activate the image display device.

As shown in FIG. 3, the control unit 102 first activates the image reduction unit 101 corresponding to an image reduction unit, acquires an image to be displayed on the information processing apparatus, and vertically shifts the image. The size is reduced to one half (step S1).
Next, the control unit 102 activates the image transfer unit 103 corresponding to the image transfer unit, and transfers the image reduced by the image reduction unit 101 to the frame memory 2 (Step S).
2).

Subsequently, the control unit 102 determines whether or not the user has instructed to end the image display apparatus (step S3). If the end has not been instructed, the above-described steps S1 and S2 are performed. Is repeated until the user instructs the image display apparatus to end, the image to be displayed on the information processing apparatus is acquired by the image reduction unit 101, and the image is reduced by half in the vertical direction. Then, the operation of transferring the reduced image to the frame memory 2 by the image transfer unit 103 is repeated.

On the other hand, if the result of determination in step S3 is that termination of the image display apparatus has been instructed, the processing in the control section 102 is terminated, and the image display apparatus is terminated.

Next, the processing contents of the image reducing section 101 corresponding to the image reducing means will be described with reference to FIGS.

FIG. 4 is a flowchart showing the processing contents of the image reducing unit 101. A program for realizing this processing is stored in the main memory 11 or the auxiliary storage device 12, is started by the control unit 102, and is executed by the central processing unit 10
Performed by FIG. 5 is an explanatory diagram of an image reduction method by the main image reduction unit 101.

FIG. 5 shows an image 60 displayed on the PC image display device 13 and stored in the PC display memory 14,
An image 60 ′ resulting from reducing the image stored in the PC display memory 14 is shown. The reduced image 60 ′ is stored in the main memory 11 or the auxiliary storage device 12.
Is stored in

The image 60 stored in the main memory 11 has two adjacent lines 62 and 63 which are to be reduced at a certain point in time in the image 60 stored in the PC display memory 14. Here, the first
The line 62 and the second line 63 are called. In addition, the first
The line 62 is composed of a plurality of pixel columns, and has one pixel 621. The second line 63 is composed of a plurality of pixel columns, and the pixel 6 in the first line 62
A pixel 631 is provided at a position 21. Image reduction
One pixel 64 is formed from each of the pixels 621 and pixels 631 forming the two lines 62 and 63.
This is realized by reducing 1 to generate one line 64.

The image 60 'resulting from the reduction of the image has one line 64 generated based on the first and second lines.
The line 64 is composed of a pixel 641 generated based on the pixel 621 and the pixel 631. Further, when generating one line from the two lines, a characteristic of an image is determined, and a reference line 61 is provided to define a generation method of the one line. Pixel 6 on two lines 63
Pixels 611 on the reference line corresponding to the positions of 21 and 631 are provided. The details of how to use the reference line will be described together with the description of the processing contents of the main image reduction unit in FIG.

As shown in FIG. 4, the image reducing unit 101
First, a reference line 61 composed of pixels for one line in an image 60 for one screen stored in the PC display memory 14 and displayed on the PC image display device 13 is generated, and each pixel constituting the reference line is generated. Is initialized (step S
11). The reference line 61 is, for example, the main memory 11
Alternatively, it may be generated as an array on the auxiliary storage device 12. In order to initialize each pixel constituting the reference line, for example, all the values of each pixel may be set to “0”.

Next, the image reducing section 101 sequentially stores two adjacent lines (first line) from the top of the image 60 for one screen stored in the PC display memory 14 and displayed on the PC image display device 13. 62 and the second line 63) (step S12), and one pixel 621 on the first line 62 and the reference line 6 at the same position as the pixel.
It is determined whether or not the pixels 611 in 1 are the same color (step S13).

As a result of the determination in step S13,
If it is determined that one pixel 621 in the first line and the pixel 611 in the reference line 61 at the same position as the pixel have the same color,
One pixel 621 and a pixel 64 at the same position as the first line in one line 64 generated by reducing a pixel 631 in the second line 63 at the same position as the pixel 621
1 is stored in the main memory 11 or the auxiliary storage device 12 (step S17).

On the other hand, as a result of the determination in step S13, one pixel 621 on the first line and a pixel 611 on the reference line 61 at the same position as the pixel are displayed.
Are not the same color, the second line, which is located at the same position as one pixel 621 on the first line 62, is further determined.
It is determined whether one pixel 631 in the line 63 and the pixel 611 in the reference line 61 at the same position as the pixel have the same color (step S14).

As a result of the determination in step S14,
If it is determined that one pixel 631 on the second line 63 at the same position as one pixel 621 on the first line and the pixel 611 on the reference line 61 at the same position as the pixel have the same color, the first line Is stored in the main memory 11 or the auxiliary storage device 12 as a pixel 641 at the same position as the first line in one line 64 generated by reduction in one line 64 (step S16).

As a result of the determination in step S14,
One pixel 631 on the second line 63 at the same position as one pixel 621 on the first line 62 and a pixel 61 on the reference line 61 at the same position as the pixel
When it is determined that 1 is not the same color, a pixel of an intermediate color between one pixel 621 in the first line 62 and the pixel 631 in the second line 63 at the same position as the pixel is generated and reduced. The data is stored in the main memory 11 or the auxiliary storage device 12 as a pixel 641 at the same position as the first line in one line 64 (step S15).

Subsequently, the image reducing unit 101 performs the above-described step S1 for all the pixels constituting the first line.
By determining whether or not the operation of step S17 has been executed, the first line 62 and the second line 63 are determined.
It is determined whether or not one line 64 has been generated on the basis of (step S18).

As a result of the determination in step S18,
If it is determined that the operations of steps S13 to S17 have not yet been performed on all the pixels forming the first line, the above steps are performed on all the pixels forming the first line. The operations of S13 to S17 are repeated to generate one line 64 based on the first line 62 and the second line 63.

On the other hand, as a result of the determination in step S18, the operations of steps S13 to S17 have already been performed on all the pixels constituting the first line, and the first line 62 and the second line 6
If it is determined that one line 64 is generated based on the third line, the second line is further stored in the PC display memory 14.
Stored in the PC image display device 13
It is determined whether or not it is the last line of the image 60 for the screen (step S19).
After the second line is newly set as the reference line 61 (step S20), the two lines further below the previously used first line and second line are set as the first line and the second line, and the second line Is stored in the PC display memory 14 until the last line of the image 60 for one screen displayed on the PC image display device 13, that is, until the reduction of one screen is completed.
The processing from step 12 to step S20 is repeated.

On the other hand, as a result of the determination in step S 19, the second line is stored in the PC display memory 14 and is the last line of the image 60 for one screen displayed on the PC image display device 13. If you decide,
Since the reduction for one screen has been completed, the main image reduction unit 1
01 is ended.

By the above processing, even when an image containing high-frequency components or an image composed of one pixel is reduced, such as a presentation image, the outline or line can be reduced without blurring or disappearing and disappearing. .

Next, the processing contents of the image transfer unit 103 corresponding to the image transfer means will be described. FIG. 6 is a flowchart showing the processing contents of the image transfer unit 103. A program for realizing this processing is stored in the main memory 11 or the auxiliary storage device 12, and is executed by the central processing unit 10.

As shown in FIG. 6, the image transfer unit 103
The main memory 1 is reduced by the image reducing unit 101 described above.
1 or the video stored in the auxiliary storage device 12 only needs to be transferred to the frame memory 2 (step S31).

As described above, the image to be displayed, such as the image displayed on the information processing apparatus, is vertically shifted by two in the image display apparatus according to the embodiment of the present invention.
Reduce this image to the first field and the second field.
Since images are commonly used as field images, images to be displayed such as images displayed on the information processing apparatus can be displayed on a monitor such as a television with a small amount of memory.
Also, when the image to be displayed is reduced in half in the vertical direction, the outline or line of an image including a high frequency component or an image composed of one pixel, such as a presentation image, is not blurred or disappears. It does not disappear.

In the above-described embodiment, the image reducing unit 101
Means that the image to be displayed is simply reduced in half only in the vertical direction, but the reduced image is further reduced in half in the horizontal direction, and then enlarged twice in the horizontal direction. Good. Thereby, even when the image displayed on the information processing device is composed of fine lines, the image displayed on a monitor such as a television becomes beautiful.

In this case, after the processing shown in FIGS. 4 and 5 described above, the image reducing section 101 performs the following processing as a horizontal reduction processing and a subsequent enlargement processing of the image.

First, the horizontal reduction processing of the image in the image reduction section 101 will be described with reference to FIGS. FIG. 7 is a flowchart showing the content of the horizontal reduction process when the image reduction unit 101 further reduces the image generated by the process in the horizontal direction after the process described in FIG.

FIG. 8 is a view for explaining a horizontal image reduction method by the main image reduction section 101. In FIG. 8,
According to the method shown in FIGS.
, The image 70 stored in the main memory 11 or the auxiliary storage device 12 and the image 7 resulting from the horizontal reduction by the main image reduction unit 101.
0 'is shown. The reduced image 70 ′ is stored in the main memory 11 or the auxiliary storage device 12. In the image 70 reduced in half in the vertical direction, the line 71 to be reduced at a certain point in time is the pixel 71 and the pixel 71 adjacent to the line 71 to be reduced.
Two. Here, pixel 711 is the first pixel, pixel 7
12 is called a second pixel. Reduction of the image in the horizontal direction is realized by generating one pixel from two pixels 711 and 712 adjacent on the line 71.

The reduced image 70 'is a line 75 obtained as a result of reducing the line 71 to be reduced.
have. The line 75 includes a pixel 751 generated based on the pixels 711 and 712. In the horizontal image reduction method performed by the image reduction unit 101, one pixel 7 out of the two pixels 711 and 712 is used.
The reference pixel 77 used to determine the characteristics of the image when generating the pixel 51 and define the method of generating the one pixel 751
Is used. The details of the method of using the reference pixel 77 will be described together with the description of the processing of the horizontal reduction in the main image reduction unit in FIG.

As shown in FIG. 7, the image reducing unit 101
After the processing described with reference to FIG. 4, first, the reference pixel 77 is generated, and the reference pixel 77 is initialized (step S4).
1). The reference pixel 77 may be generated as a variable on the main memory 11 or the auxiliary storage device 12, for example.
In order to initialize the reference pixel, for example, the value of the reference pixel 77 may be set to “0”.

Next, the image reducing section 101 performs the processing shown in FIG.
, One line 71 is acquired in order from the top of the image 70 reduced in the vertical direction by half (step S42), and two lines adjacent to the one line 71 are sequentially acquired from the left.
Two pixels (a first pixel 711 and a second pixel 712) are acquired (step S43), and it is determined whether the first pixel 711 and the reference pixel 77 have the same color (step S4).
4).

As a result of the determination in step S44,
If it is determined that the first pixel 711 and the reference pixel 77 have the same color, the second pixel 712 is stored in the main memory 11 or the auxiliary storage device 12 as one pixel 751 generated by reduction (step S48). ).

On the other hand, if it is determined in step S44 that the first pixel 711 and the reference pixel 77 are not the same color, it is further determined whether the second pixel 712 and the reference pixel 77 are the same color. (Step S4
5).

As a result of the determination in step S45,
If it is determined that the second pixel 712 and the reference pixel 77 have the same color, the first pixel 711 is stored in the main memory 11 or the auxiliary storage device 12 as one pixel 751 generated by reduction (step S46). ).

On the other hand, if it is determined in step S45 that the second pixel 712 and the reference pixel 77 are not the same color, a pixel having an intermediate color between the first pixel 711 and the second pixel 712 is generated. Then, it is stored in the main memory 11 or the auxiliary storage device 12 as one pixel 751 generated by the reduction (step S47).

Subsequently, the image reducing section 101 determines whether or not the second pixel 712 is the rightmost pixel in the one line 71 obtained in step S42, thereby obtaining the second pixel 712 in step S42. It is determined whether or not the generation of a horizontally reduced line 75 from one line 71 has been completed (step S49).

As a result of the determination in step S49,
If it is determined that the second pixel 712 is not the rightmost pixel in the one line 71 obtained in step S42, the second pixel is newly set as the reference pixel 77 (step S50). Returning to step S43, two pixels that are further adjacent to the second pixel 712 are acquired, and are newly set as the first pixel and the second pixel. The second pixel is the rightmost end of the one line 71 acquired in step S42. Until it becomes a pixel, that is, the line 7
The processes in steps S43 to S50 are repeated until the generation of the horizontally reduced line 75 from 1 is completed.

On the other hand, as a result of the determination in step S49, the second pixel 712 has already become the rightmost pixel in the one line 71 obtained in step S42, and a line 75 reduced in the horizontal direction from this line 71 is generated. If it is determined that the processing has been completed,
Is determined at the lowermost end of the image 70 reduced in half in the vertical direction, that is, whether it is the last line or not.
It is determined whether or not the reduction in the horizontal direction has been completed for all the lines in the image 70 reduced in half in the vertical direction (step S51).

As a result of the determination in step S51,
If the one line 71 obtained in the step S42 is not the lowermost end of the image 70 reduced in half in the vertical direction, all the lines in the image 70 are still in the horizontal direction. Since the reduction has not been completed, the process returns to step S41 to acquire a line one step lower than the line 71, and as a new line 71, an image in which the line 71 is reduced in half in the vertical direction. The processes in steps S41 to S51 are repeated until the lowermost line of the image 70 is reached, that is, until the horizontal reduction of all the lines in the image 70 is completed.

On the other hand, as a result of the judgment in step S51, one line 71 acquired in step S42 is obtained.
Is the lowermost end of the image 70 reduced in half in the vertical direction, since all the lines in the image 70 have been reduced in the horizontal direction, the image reduction unit 10
The process of reducing the image in the horizontal direction in 1 is ended.

Next, a description will be given, with reference to FIGS. 9 and 10, of a process of enlarging an image in the horizontal direction in the image reducing unit 101. FIG. FIG. 9 is a flowchart illustrating the content of the horizontal enlargement process when the image reduction unit 101 enlarges the image generated in the horizontal direction after the horizontal reduction process described above.

FIG. 10 is an explanatory diagram of a horizontal image enlargement method by the main image reduction unit 101. In FIG.
An image 80 that has been reduced in the horizontal direction by the image reduction unit 101 and stored in the main memory 11 or the auxiliary storage device 12 and an image 80 ′ that has been expanded in the horizontal direction by the main image reduction unit 101 are shown. . The enlarged image 80 ′ is stored in the main memory 11 or the auxiliary storage device 12.
Is stored in The image 80 reduced in the horizontal direction is
At a certain point in time, there is a line 81 to be enlarged in the horizontal direction.
Is configured. The horizontal enlargement of the image is
This is realized by generating two pixels from 11. Image 8 resulting from horizontal enlargement by main image reduction section 101
0 ′ has a line 85 obtained as a result of enlarging the line 81 to be enlarged.
Are the pixels 851 and 8 generated based on the pixels 811
52.

As shown in FIG. 9, the image reducing unit 101
After the above-described horizontal reduction processing, first, one line 81 is obtained sequentially from the top of the image 80 reduced in the horizontal direction (step S61), and one pixel 811 is sequentially obtained from the left of the one line 81. Obtain (step S62).

Next, the image reducing section 101 generates two pixels (pixels 851 and 852) of the same color as the one pixel 811 and stores them in the main memory 11 or the auxiliary storage device 12 (step S63). . To generate two pixels of the same color as the one pixel 811,
It may be generated by copying the pixel values of the two pixels 811.

Subsequently, the image reduction unit 101 determines that one pixel 811 obtained in step S62 is in the step S62.
By determining whether the pixel is the rightmost pixel in one line 81 acquired in step 61,
It is determined whether the generation of the line 85 enlarged in the horizontal direction from the one line 81 acquired in 61 has been completed (step S64).

As a result of the determination in step S64,
Still, one pixel 811 acquired in step S62
If it is determined that is not the rightmost pixel in the one line 81 acquired in step S61, the process returns to step S62, and the pixel on the right of the one pixel 811 is acquired and set as the pixel 811. Until 811 becomes the rightmost pixel in one line 81 acquired in the step S61, that is, until the generation of the line 85 expanded in the horizontal direction from the line 81 is completed.
The processing from 62 to S64 is repeated.

On the other hand, as a result of the determination in the step S64, the one pixel 811 obtained in the step S62 has already become the rightmost pixel in the one line 81 obtained in the step S61. When it is determined that the generation of the enlarged line 85 has been completed, it is further determined whether or not the line 81 is the lowermost end of the horizontally oriented image 80, that is, the last line, thereby reducing the horizontal direction. It is determined whether the horizontal enlargement has been completed for all the lines in the image 80 thus obtained (step S65).

As a result of the determination in step S65,
If the one line 81 obtained in step S61 is not the lowermost end of the image 80 reduced in the horizontal direction, the horizontal expansion of all the lines in the image 80 has not been completed yet. No, so step S61
To obtain a line one step lower than the line 81, and as a new line 81, until the line 81 becomes the lowermost line of the image 80 reduced in the horizontal direction.
That is, the processes in steps S61 to S65 are repeated until the horizontal enlargement of all the lines in the image 80 is completed.

On the other hand, as a result of the judgment in step S65, one line 81 acquired in step S61 is obtained.
Is the lowermost end of the image 80 reduced in the horizontal direction, the horizontal expansion of all the lines in the image 80 has been completed. The process ends.

After the image to be displayed is reduced by half in the vertical direction by the processing of the image reducing unit 101 described above,
Further, an image obtained by reducing the reduced image by half in the horizontal direction is enlarged twice in the horizontal direction to generate an image in which an image to be finally displayed is reduced by half in the vertical direction. I do. Thus, for example, even when an image displayed on the information processing device is composed of one pixel, the image is displayed not as two vertically long pixels but as a balanced point of two pixels vertically and horizontally. The image when displayed on a monitor of John or the like becomes clear.

In the above-described embodiment, the control unit 102 controls the image reduction unit 1 regardless of whether or not the image to be displayed has changed.
In step 01, the image to be displayed is reduced, and the image is transferred from the image transfer unit 103 to the frame memory 2. In contrast, in the processing described below, the control unit 1
02 activates the image reduction unit 101 and the image transfer unit 103 only when there is a change in the image to be displayed, and executes the reduction process of the image to be displayed and the transfer process to the frame memory 2. The load on the central processing unit 10 can be reduced.

FIG. 11 shows a control unit 102 for realizing this function.
4 is a flowchart showing the processing content of the control unit 102, which replaces the processing of the control unit 102 shown in FIG. A program that implements this processing is stored in the main memory 11 or the auxiliary storage device 12, is started by the control unit 102, and is executed by the central processing unit 10.

As shown in FIG. 11, the control unit 102 for realizing this function first determines whether or not a change has occurred in the image displayed on the PC image display device 13 (pixels (specific pixels and (Step S)
71). The specific pixel may be a pixel at an arbitrary position in the image stored in the PC display memory 14.

An example of the position of the specific pixel will be described with reference to FIG. FIG. 12 shows a case where specific pixels are arranged vertically. That is, from the image 90 stored in the PC display memory 14, columns of pixels arranged vertically at predetermined intervals can be extracted and used as columns 91 to 94 of specific pixels.

Next, the control unit 102 determines whether there is a difference between the previously acquired color data of the specific pixel and the color data of the specific pixel, thereby determining whether there is a change in the image to be displayed. Step S72). If the color data of the specific pixel has not been obtained before, that is, if the determination in step S72 is performed for the first time, it is determined that there is a difference from the color data of the specific pixel.

As a result of the determination in step S72,
If it is determined that there is a difference between the previously obtained color data of the specific pixel and the image to be displayed, there is a change in the image to be displayed. , And divide the image by half in the vertical direction.
Then, the image transfer unit 103 is activated to transfer the reduced image to the frame memory 2 (step S74).

On the other hand, if it is determined in step S72 that there is no difference between the previously obtained color data of the specific pixel and the image data to be displayed, it is determined that there is no change in the image to be displayed. Unit 101 and Image Transfer Unit 103
Does not start.

Subsequently, the control unit 102 determines whether or not the end of the main image display device has been instructed by the user (step S75). If the end has not been instructed, the control unit 102 displays the main image display from the user. Steps S71 to S75 are repeated until the end of the apparatus is instructed. Only when a specific pixel changes, an image to be displayed on the information processing apparatus is acquired by the image reducing unit 101, and the image is displayed in the vertical direction. The operation of transferring the reduced image to the frame memory 2 by the image transfer unit 103 is repeated.

On the other hand, if the result of determination in step S75 is that termination of the image display apparatus has been instructed, the processing in the control section 102 ends, and the image display apparatus ends.

Only when there is a change in the image to be displayed by the processing of the control unit 102 described above, the image reduction unit 101 and the image transfer unit 103 are started, and the reduction of the image to be displayed and the frame memory are performed. 2, the load on the central processing unit 10 can be reduced.

[0092]

As described above, according to the present invention, an image display which can display an image to be displayed such as an image displayed on an information processing apparatus on a monitor such as a television with a small memory configuration. An apparatus can be provided.

Further, according to the image reduction method of the present invention, an image including a high frequency component such as a presentation image or an image composed of one pixel can be reduced without blurring or disappearing contours and lines. it can.

Further, by applying the image reduction method of the present invention to the image display device, an image including a high-frequency component or an image composed of one pixel, such as a presentation image, can be seen with outlines and lines blurred or disappearing. An image display device that does not disappear can be provided.

According to the present invention, an image capturing card (video capture board) having a small frame memory capacity.
Can be used to display a non-interlaced PC screen on an interlaced TV screen.

[Brief description of the drawings]

FIG. 1 shows a hardware configuration of an information processing apparatus such as a personal computer to which an image reduction method according to an embodiment of the present invention and an image display apparatus using the same can be applied, and functional blocks executed by a central processing unit. Figure.

FIG. 2 is an explanatory diagram showing a relationship between an image reduction method according to an embodiment of the present invention, and hardware of an image display device using the method and functional blocks executed by a central processing unit.

FIG. 3 is a flowchart showing processing contents of a control unit according to the embodiment of the present invention.

FIG. 4 is a flowchart showing processing contents of an image reduction unit according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of an image reducing method by the image reducing unit according to the embodiment of the present invention.

FIG. 6 is a flowchart illustrating processing performed by an image transfer unit according to the embodiment of the present invention.

FIG. 7 is a flowchart showing processing contents for horizontal reduction processing of an image by an image reduction unit according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram of a horizontal image reduction method by the image reduction unit according to the embodiment of the present invention.

FIG. 9 is a flowchart showing processing contents for a horizontal enlargement processing of an image by the image reducing unit according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram of a horizontal image enlarging method by the image reducing unit according to the embodiment of the present invention.

FIG. 11 shows an embodiment of the present invention, which activates an image reduction unit and an image transfer unit only when there is a change in an image to be displayed, and reduces the image to be displayed and transfers the image to the frame memory. 5 is a flowchart illustrating processing performed by a control unit that implements a function to be executed.

FIG. 12 is a diagram illustrating an example of a position of a specific pixel for determining whether or not a change has occurred in an image displayed on a screen of an information processing apparatus (particularly, an example in a case where specific pixels are vertically arranged). Is shown).

FIG. 13 illustrates a display method of an image by an interlace method on a monitor such as a television.

[Description of Signs] 1 Personal computer 2 Frame memory 3 Television signal encoding device 4 Television image display device 5 Transfer control device 10 Central processing unit 11 Main memory 12 Auxiliary storage device 13 PC image display device 14 PC display memory 15 Input device 16 Bus 101 Image reduction unit 102 Control unit 103 Image transfer unit 60 Screen before reduction processing 60 ′ Vertically reduced screen 61 Reference line 611 Reference pixel 62 Reduction target first line 621 Reduction target first pixel 63 Reduction target second line 64 Vertical reduction line 641 Vertical reduction pixel 631 Reduction target second pixel 70 Screen reduced vertically 70 'Screen reduced horizontally 71 Reduction target line 711 Reduction target first pixel 712 Reduction target second pixel 75 Horizontal reduction line 751 Horizontal reduction Pixels 77 reference pixels

Claims (6)

[Claims] 1. A method for reducing an image, wherein one pixel is generated for two adjacent pixels by using one pixel adjacent to the two pixels in the same direction. When a pixel having the same color as the one pixel exists, a pixel having a different color is adopted. When a pixel having the same color as the one pixel does not exist among the two pixels, the two pixels are used. An image reduction method comprising generating a pixel having an average color. 2. An image display device comprising at least a television signal encoding means for converting a first field image and a second field image into a television signal based on the image, and displaying the image on a television monitor. Image reduction means for acquiring an image to be reduced and reducing the image in half in the vertical direction, image storage means for storing the reduced image, and image for transferring the reduced image to the image storage means Transfer means, and a first image in a television signal interlaced system for storing the image stored in the image storage means.
Transfer control means for transferring the image of the field and the second field to the television signal encoding means. 3. An image display device according to claim 2, wherein said image reduction means adopts the image reduction method according to claim 1. 4. An image display apparatus according to claim 2, wherein said television signal encoding means displays the images of the first field and the second field on the same scanning line on a television monitor. 5. The image reduction device according to claim 2, wherein the image reduction unit acquires an image to be displayed on a television monitor, reduces the image in a vertical direction by half, and
Generating an image in which the image to be displayed on the television monitor is reduced in half in the vertical direction by reducing the image in half in the horizontal direction and then enlarging the image in double in the horizontal direction. An image display device characterized by the above-mentioned. 6. The image display device according to claim 2, wherein the image reduction device and the image transfer device perform the image display only when the color of a specific pixel in the image to be displayed changes. An image display device for reducing the image to be displayed and transferring the image to the image storage means.