JP2000050159A - Multi-screen video generation device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately remove the flickering on a screen. SOLUTION: A picture data input part 1 inputs picture data of a JPEG(joint photographic expert group) system and stores them in a DRAM 2. A picture conversion part 31 converts the picture data in the DRAM 2 into a BPM (bit map) system. A picture reduction part 32 reduces the converted picture data into a prescribed reduction size in accordance with indication information of a screen division number indication part 33. The picture reduction part 32 stores the reduced picture data in a whole screen (division screen) VRAM 4. A high frequency component in the vertical direction in the picture data stored in the VRAM 4 is removed by either of interpolation filters 5a-5n connected through a switch 6. After the picture data from which the high frequency component is removed are converted into an RGB signal by a D/A converter 7, are encoded to an NTSC video signal by an NTSC(national television system committee) encoder 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a multi-screen video generation apparatus and a multi-screen video generation method capable of eliminating flickering on a screen.

[0002]

2. Description of the Related Art There is known a video generation apparatus for generating a video signal from image data in a predetermined format (compression format or the like). Such an image generation device is a PC (PCMCIA;
sonalComputer Memory Card International Associatio
n) Image data is obtained via a card, a floppy disk, RS232C, etc., subjected to a predetermined image conversion process, and then D / A (digital / analog) converted to NTSC
(National Television System Committee) etc. As a result, the video generation device can convert the image data into a still image of interlaced scanning and display it on a predetermined display device.

Such a video generation apparatus not only generates a full-screen video signal from one display of image data, but also generates a multi-screen video signal divided into a plurality of screens from a plurality of display image data. Also included is a multi-screen video generation device capable of generating. For example, when dividing into 16 parts, the multi-screen image generating apparatus reduces image data for 16 displays to 1/16 of the screen size, generates a video signal obtained by dividing the entire screen into 16 screens, and displays the signal on the display device. I do. At this time, in the image divided into 16 screens, the screens flicker due to the high vertical frequency of the boundary between the vertically divided screens.

As a countermeasure against this phenomenon, the conventional multi-screen video generating apparatus limits the band in the vertical direction by using a low-pass filter in the vertical direction and removes high-frequency components in the vertical direction to prevent flicker on the screen. Hereinafter, a conventional multi-screen video generation device will be described.

FIG. 4 is a schematic diagram of a conventional multi-screen video generating apparatus having a vertical band limiting function. As shown in FIG. 4, the multi-screen video generation device includes an image data input unit 1
01, DRAM 102, image processing unit 103, VR
It comprises an AM 104, an interpolation filter 105, a D / A converter 106, and an NTSC encoder 107.

[0006] The image data input unit 101 is a PC (PCMCI
A; Personal Computer Memory Card International Asso
ciation) Read and input image data from a card, a flexible disk, or the like. Further, the image data input unit 101 is provided with an RS232C or LAN (Local Area Network).
Image data may be input via k). The image data input unit 101 is, for example, a JPEG (Joint Photograph).
ic Experts Group), and supplies the image data to the DRAM 102.

A DRAM (Dynamic Random Access Memor)
y) 102 stores the JPEG format image data supplied from the image data input unit 101. In addition, DRAM
Reference numeral 102 is connected to the image processing unit 103 via a bus line 108.

The image processing unit 103 includes a CPU (Central Pr
image conversion unit 131
And an image reduction unit 132.

An image converter 131 reads out JPEG format image data stored in the DRAM 102,
The image data is converted into image data in a PM (bitmap) format. The image conversion unit 131 converts the converted image data into an image
32.

The image reducing section 132 reduces the image data supplied from the image converting section 131 to a predetermined reduced size. Note that the image reducing unit 132 reduces the obtained image data to 1: 1 when displaying the obtained image data on the full screen. The image reduction unit 132 supplies the reduced image data to the VRAM 104.

A VRAM (Video RAM) 104 holds the image data supplied from the image reduction section 132 for the entire screen (one display screen). The VRAM 104 is connected to the image processing unit 103 via a bus line 109.

The interpolation filter 105 comprises a low-pass filter or the like, and removes high-frequency components in the vertical direction from the image data held in the VRAM 104,
06.

A D / A (digital / analog) converter 106 performs D / A conversion of the image data from which high-frequency components in the vertical direction have been removed by the interpolation filter 105, and performs RGB conversion.
(R: red, G: green, B: blue) signals are generated. The D / A converter 106 supplies the generated RGB signals to the NTSC encoder 107.

The NTSC encoder 107 encodes the RGB signals into NTSC video signals. The NTSC encoder 107 converts the encoded Y (luminance) signal and C
A (color) signal is output to a display device (not shown).

The operation of the conventional multi-screen image generating apparatus shown in FIG. 4 will be described below. Image data input unit 101
Reads, for example, JPEG image data stored in a PC card and temporarily stores the data in the DRAM 102. The image conversion unit 131 acquires JPEG format image data stored in the DRAM 102, converts the data into BPM format image data, and supplies the image data to the image reduction unit 132. The image reduction unit 132 reduces the image data sent from the image conversion unit 131 to a predetermined reduction size selected by the user, and supplies the reduced image data to the VRAM 104.

The VRAM 104 sequentially stores the image data sent from the image reduction unit 132 and holds image data for divided display of one display screen. VRAM 104
Is passed through the interpolation filter 105 and converted into three analog RGB signals by the D / A converter 106. The NTSC encoder 107 further converts the three RGB signals into a Y signal for NTSC.
The converted Y signal and C signal are output to a display device (not shown), and a still image of one display screen is displayed on the display device. As a result, by passing the image data stored in the VRAM 104 through the interpolation filter 105 constituted by a low-pass filter, high-frequency components in the vertical direction of the image are removed, and flicker on the screen is suppressed.

[0017]

However, such a multi-screen image generating apparatus has the following problems. When removing the high-frequency components in the vertical direction of the image data, the high-frequency components in the vertical direction are uniformly attenuated by the low-pass filter, so that the resolution in the vertical direction is impaired at the same time, resulting in an overall blurred image.

Further, since the flicker generated on the screen differs depending on the reduced size of the image data according to the number of divisions of the screen, a low-pass filter with a fixed cutoff frequency for removing high-frequency components completely eliminates the flicker on the screen. In some cases, the vertical resolution cannot be removed, or on the contrary, the vertical resolution significantly deteriorates.

The present invention has been made in view of the above situation, and provides a multi-screen video generating apparatus and a multi-screen video generating method capable of appropriately removing screen flicker without impairing the vertical resolution of an image. The purpose is to provide.

[0020]

In order to achieve the above object, a multi-screen video generating apparatus according to a first aspect of the present invention comprises: a dividing number instructing means for instructing a dividing number of a display screen;
Image data input means for sequentially inputting each image data corresponding to the number of divisions instructed by the division number instruction means, and dividing the image data inputted by the image data input means into divisions instructed by the division number instruction means An image data reduction unit for reducing the image data to a predetermined size corresponding to the number of images, and a display number corresponding to the number of divisions instructed by the division number instruction unit, the image data reduced by the image data reduction unit. Image data storage means for separately storing, and high frequency component removal for removing a predetermined high frequency component corresponding to the number of divisions designated by the division number designation means from a plurality of image data stored in the image data storage means Means,
Video signal conversion means for converting the image data from which high frequency components have been removed by the high frequency component removal means into a video signal,
It is characterized by having.

According to the present invention, the image data input means sequentially inputs each image data corresponding to the division number designated by the division number designation means. The image data reduction means reduces the image data input by the image data input means to image data of a predetermined size corresponding to the number of divisions designated by the division number designation means. The image data storage means stores the image data reduced by the image data reduction means for the number of displays corresponding to the number of divisions designated by the division number designation means. The high frequency component removing unit removes a predetermined high frequency component corresponding to the number of divisions designated by the division number designating unit from a plurality of image data stored in the image data storage unit. As a result, high-frequency components are optimally removed according to the number of divisions of the screen, so that flickering of the screen can be appropriately removed without impairing the vertical resolution of the image.

The high frequency component removing means includes a plurality of low pass filters having different cutoff frequencies,
The high-frequency component removing means may remove high-frequency components in the vertical direction from image data using the low-pass filter having a cutoff frequency corresponding to the number of divisions specified by the number-of-division instruction means. In this case, a high-frequency component in the vertical direction is removed from the image data by using a low-pass filter having an optimal cutoff frequency according to the number of divisions of the screen, so that the screen flicker can be prevented without impairing the vertical resolution of the image. Can be properly removed.

[0023] The low-pass filter may have a predetermined cutoff frequency for minimizing the loss of vertical resolution corresponding to the number of screen divisions. In this case, a high-frequency component in the vertical direction is removed from the image data by using a low-pass filter having an optimal cutoff frequency according to the number of divisions of the screen, so that the screen flicker can be prevented without impairing the vertical resolution of the image. Can be properly removed.

In order to achieve the above object, a second aspect of the present invention is provided.
The multi-screen video generating apparatus according to the aspect of the present invention comprises: a division number instructing unit that instructs the number of divisions of the display screen according to a predetermined setting; and a JPEG format corresponding to the division number instructed by the division number instructing unit. Image data input means for sequentially inputting image data, image data conversion means for converting JPEG format image data input by the image data input means into BPM format image data, and image data conversion means for converting the image data. Image data reduction means for reducing image data in BPM format to image data of a predetermined size corresponding to the number of divisions instructed by the instruction means, and dividing the image data reduced by the image data reduction means into Image data storage means for storing the display number corresponding to the division number designated by the number designation means, and a plurality of low-pass filters; Using a low-pass filter having a cutoff frequency corresponding to the number of divisions designated by the selected division number designation means, removing high frequency components in the vertical direction from the plurality of image data stored in the image data storage means. It is characterized by comprising a high-frequency component removing unit and a video signal converting unit for converting the image data from which the high-frequency component has been removed by the high-frequency component removing unit into a video signal.

According to the present invention, the image data input means sequentially inputs each of the JPEG format image data corresponding to the number of divisions designated by the division number designating means. The image data conversion means outputs the J input by the image data input means.
PEG format image data is converted into BPM format image data. The image data reducing means reduces the BPM format image data converted by the image data converting means to image data of a predetermined size corresponding to the number of divisions designated by the division number designating means. The image data storage means stores the image data reduced by the image data reduction means for the number of displays corresponding to the number of divisions designated by the division number designation means. The high-frequency component removing means uses a low-pass filter having a cutoff frequency corresponding to the number of divisions specified by the number-of-divisions instructing means selected from the plurality of low-pass filters, and uses a plurality of image data stored in the image data To remove high frequency components in the vertical direction. As a result, the high-frequency component in the vertical direction is removed from the image data by using a low-pass filter having an optimal cutoff frequency according to the number of screen divisions, so that the screen flicker can be prevented without deteriorating the vertical resolution of the image. Can be properly removed.

In order to achieve the above object, a third aspect of the present invention is provided.
The method for generating a multi-screen video according to the aspect of the present invention comprises: An image data reducing step of reducing the image data input in the image data input step to image data of a predetermined size corresponding to the number of divisions instructed in the division number instruction step; From the image data reduced by the data reduction step, a high-frequency component removing step of removing a predetermined high-frequency component corresponding to the number of divisions instructed in the division number instructing step; Video signal converting step of converting the removed image data into a video signal. .

According to the present invention, in the image data input step, each image data corresponding to the number of divisions designated in the division number designation step is sequentially inputted. In the image data reduction step, the image data input in the image data input step is reduced to image data of a predetermined size corresponding to the number of divisions specified in the division number instruction step. The high frequency component removing step removes a predetermined high frequency component corresponding to the number of divisions specified in the division number specifying step from the image data reduced in the image data reducing step. As a result, high-frequency components are optimally removed according to the number of divisions of the screen, so that flickering of the screen can be appropriately removed without impairing the vertical resolution of the image.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-screen video generating apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration of a multi-screen video generating apparatus according to an embodiment of the present invention. As shown in FIG. 1, this multi-screen video generation device includes an image data input unit 1, a DRAM 2, an image processing unit 3, a VR
AM4, interpolation filters 5a to 5n, switch 6,
It comprises a D / A converter 7 and an NTSC encoder 8.

The image data input section 1 reads and inputs image data from a PC card, a flexible disk or the like. Further, the image data input unit 101 is provided with an RS232C
Alternatively, image data may be input via a LAN or the like. The image data input unit 1 inputs, for example, image data compressed in the JPEG format and supplies it to the DRAM 102.

The DRAM 2 stores the JPEG format image data supplied from the image data input unit 1. In addition,
The DRAM 2 is connected to the image processing unit 3 by a bus line 11.

The image processing unit 3 comprises a CPU and the like.
An image conversion unit 31, an image reduction unit 32, and a screen division number instruction unit 33 are provided.

The image converter 31 reads out the JPEG format image data stored in the DRAM 2 and converts it into BPM format image data. The image conversion unit 31 supplies the converted image data to the image reduction unit 32.

The image reducing section 32 reduces the image data obtained from the image converting section 31 to a predetermined reduced size according to the instruction information supplied from the screen division number instruction section 33.
For example, when the instruction information of the screen division number 4 is supplied from the screen division number instruction section 33, the image reduction section 32 reduces the image data acquired from the image conversion section 31 to a quarter of the screen size. . In addition, when the instruction information of the screen division number 1 (full screen display) is supplied from the screen division number instruction unit 33, the image reduction unit 32 reduces the image data acquired from the image conversion unit 31 to 1: 1. The image reducing unit 32 supplies the reduced image data to the VRAM 4.

The screen division number instructing section 32 supplies instruction information to the image reduction section 32 and also supplies a control signal 13 to the switch 6 in accordance with the division number information set in a storage section (not shown).

The VRAM 4 holds the image data supplied from the image reduction section 32 for the entire screen (one display screen).
The VRAM 4 is connected to the image processing unit 3 via a bus line 12.

The interpolation filters 5a to 5n are composed of n low-pass filters having different cutoff frequencies and the like. The filters selected by the switch 6 remove high-frequency components in the vertical direction from the image data held in the VRAM 4, and / A converter 7.

More specifically, the interpolation filters 5a to 5a
For n, as shown in FIG. 2, a predetermined cutoff frequency is set corresponding to the number of screen divisions. The cutoff frequency shown in FIG. 2 is determined experimentally or theoretically so that the removal of the high-frequency component in the vertical direction of the image data and the loss of the resolution in the vertical direction have an optimal balance for each screen division number. This is the determined frequency. That is, the interpolation filters 5a to 5n correspond to the VRAMs corresponding to the respective screen division numbers.
The high-frequency component in the vertical direction is appropriately removed from the image data held in No. 4.

The interpolation filters 5a to 5n shown in FIG.
_Is a _{f v1, f v2, f v3} , f v 4 frequency low in the order of .... That is, as the number of screen divisions increases, the corresponding cutoff frequency decreases.

Returning to FIG. 1, the switch 6 is connected to n contacts connected to each of the interpolation filters 5a to 5n and D /
And one contact connected to the A converter 7. The switch 6 connects any one of the interpolation filters 5 a to 5 n to the D / A converter 7 in accordance with the control signal 13 supplied from the screen division number instruction unit 33.

The D / A converter 7 includes an interpolation filter 5a
The image data from which the high-frequency component in the vertical direction has been removed by any one of the filters 5 to 5n is subjected to D / A conversion to generate RGB signals. The D / A converter 7 supplies the generated RGB signals to the NTSC encoder 8.

The NTSC encoder 8 converts the RGB signals to N
Encode to a TSC video signal. The NTSC encoder 8 outputs the encoded Y signal and C signal to a display device (not shown).

Next, an image generating operation of the multi-screen image generating apparatus according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 shows that the multi-screen video generation device
6 is a timing chart illustrating an operation of dividing image data for display and generating four screen images on one display screen. It should be noted that the screen division number display section 33 is provided with the image reduction section 32.
Is supplied to the switch 6 and the control signal 13 having four screen divisions is supplied to the switch 6.

First, the image data input unit 1 is, for example, a PC
The image data A, which is the first image data of the JPEG system, is input from the card and supplied to the DRAM 2 (timing T1). The DRAM 2 stores the image data A.

The image converter 31 reads the JPEG format image data A stored in the DRAM 2 and converts it into BPM format image data (timing T2). The data image conversion unit 31 supplies the image data A converted into the BPM format to the image reduction unit 32.

The image reduction unit 32 obtains the acquired image data A
To the screen division number 4 supplied from the screen division number instruction unit 33.
Is reduced to a quarter size according to the instruction information (timing T3). The image reducing unit 32 supplies the reduced image data A to the VRAM 4. The VRAM 4 stores the image data A reduced to a quarter size.

On the other hand, when the image conversion unit 31 completes the conversion of the image data A (timing T2), the image data input unit 1 inputs the image data B which is the second image data from the PC card, and Supply (timing T
4). That is, the image data input unit 1 is connected to the image reduction unit 3
In parallel with the reduction of the image data A (timing T3), the image data B is supplied to the DRAM 2 and stored. The image data B is converted into a JPEG
After the format is converted to the BPM format, the image is reduced to a quarter size by the image reducing unit 32 and stored in the VRAM 4.

Similarly, the image data C as the third image data and the image data D as the fourth image data are sequentially supplied to the DRAM 2 by the image data input unit 1, and After being converted from the JPEG format to the BPM format, the image is reduced to a quarter size by the image reducing unit 32 and is sequentially supplied to the VRAM 4. In this manner, the VRAM 4 stores image data for four displays of the image data A to D.

The switch 6 connects the interpolation filter 5 b corresponding to the screen division number 4 and the D / A converter 7 in accordance with the control signal 13 of the screen division number 4 supplied from the screen division number instructing section 33. 5b is VRAM4
The high-frequency component in the vertical direction is appropriately removed from the image data held at (T5).

The D / A converter 7 includes an interpolation filter 5b
Performs D / A conversion on the image data from which the high frequency components in the vertical direction have been removed, and sequentially generates RGB signals (timing T6). The D / A converter 7 supplies the generated RGB signals to the NTSC encoder 8.

The NTSC encoder 8 converts the acquired RGB
The signals are sequentially encoded into NTSC video signals (timing T7). The NTSC encoder 8 outputs the encoded Y signal and C signal to a display device (not shown).

As a result, the high frequency component in the vertical direction is removed from the image data by using the interpolation filter having the optimum cutoff frequency according to the number of divisions of the screen, so that the vertical resolution of the image is not impaired. The flicker can be properly removed.

In the above-described embodiment, the optimum interpolation filter corresponding to the number of screen divisions is selected from a plurality of interpolation filters having different cutoff frequencies. An optimal cutoff frequency corresponding to the number of divisions may be set. For example, by using one interpolation filter that can switch n coefficients of the interpolation filter, and by switching to a coefficient corresponding to the number of screen divisions, an optimal cutoff frequency is set in the interpolation filter. High frequency components can be removed.

In the above-described embodiment, the JPEG format image data is converted into the BPM format image data by the image conversion unit, but the format (compression format, etc.) of the image data is arbitrary. For example, MPEG (Moving Picture Image Cor
(ding Experts Group) format image data may be sequentially converted to BPM format image data to display a screen-divided moving image.

In the above-described embodiment, an NTSC encoder encodes an NTSC video signal. However, the system of the encoded video signal is arbitrary. For example, PA
L (Phase Alternation by Line) encoder
It may be encoded into a PAL video signal.

In the above-described embodiment, the screen is divided into divisions in which the size of the divided screen is equal, but the division number is arbitrary. For example, the screen may be divided into halves so as to be arranged side by side (horizontal direction), and the left or right divided screen may be further divided into halves so as to be vertically arranged (vertical direction). At that time, the high frequency component in the vertical direction may be removed by an interpolation filter having a cutoff frequency equivalent to the number of screen divisions of four.

[0057]

As described above, according to the present invention,
It is possible to appropriately remove the flicker on the screen without deteriorating the vertical resolution of the image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a multi-screen video generation device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a cutoff frequency in an interpolation filter corresponding to the number of screen divisions.

FIG. 3 is a timing chart illustrating an image generation operation of the multi-screen image generation device according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a conventional multi-screen video generation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image data input part 2 DRAM 3 Image processing part 4 VRAM 5a-5n Interpolation filter 6 Switch 7 D / A converter 8 NTSC encoder 11, 12 Bus line 13 Control signal 31 Image conversion part 32 Image reduction part 33 Screen division number indication part 101 image data input unit 102 DRAM 103 image processing unit 104 VRAM 105 interpolation filter 106 D / A converter 107 NTSC encoder 108, 109 bus line 131 image conversion unit 132 image reduction unit

Claims (5)

[Claims] 1. A division number designating means for designating the number of divisions of a display screen; an image data inputting means for sequentially inputting image data corresponding to the division number designated by the division number designating means; Image data reducing means for reducing the image data input by the means to image data of a predetermined size corresponding to the number of divisions instructed by the division number instructing means; and an image reduced by the image data reducing means. Image data storage means for storing data for a display number corresponding to the number of divisions instructed by the division number instruction means; and instructing the division number instruction means from a plurality of image data stored in the image data storage means. High-frequency component removing means for removing a predetermined high-frequency component corresponding to the divided number, and an image data from which high-frequency components have been removed by the high-frequency component removing means. Multi-screen image generation apparatus characterized by comprising: a video signal conversion means for converting the data into a video signal, a. 2. The high-frequency component removing means includes a plurality of low-pass filters having different cut-off frequencies, and the high-frequency component removing means has a cut-off frequency corresponding to the number of divisions designated by the division number designating means. The multi-screen video generation apparatus according to claim 1, wherein the high-frequency component in the vertical direction is removed from the image data by using the low-pass filter having: 3. The multi-screen image according to claim 2, wherein the low-pass filter has a predetermined cutoff frequency that minimizes the loss of vertical resolution according to the number of screen divisions. Generator. 4. A division number instructing means for instructing the number of divisions of a display screen according to a predetermined setting, and JPEG format image data corresponding to the number of divisions instructed by said division number instructing means are sequentially input. Image data input means; image data conversion means for converting JPEG format image data input by the image data input means into BPM format image data; and BPM format image data converted by the image data conversion means. Image data reducing means for reducing image data of a predetermined size corresponding to the number of divisions instructed by the number of division instructing means; image data reduced by the image data reducing means; Image data storage means for storing the number of displays corresponding to the number of divisions instructed, and a plurality of low-pass filters selected from High-frequency component removal for removing a vertical high-frequency component from a plurality of image data stored in the image data storage means using a low-pass filter having a cutoff frequency corresponding to the number of divisions specified by the division number specification means. And a video signal converting means for converting the image data from which the high frequency component has been removed by the high frequency component removing means into a video signal. 5. A division number instructing step for instructing a division number of a display screen; an image data inputting step of sequentially inputting image data corresponding to the division number instructed in the division number instructing step; An image data reduction step of reducing the image data input in the input step to image data of a predetermined size corresponding to the number of divisions instructed in the division number instruction step; A high-frequency component removing step of removing a predetermined high-frequency component corresponding to the number of divisions instructed in the division number instructing step from the divided image data, and removing the high-frequency component by the high-frequency component removing step. A video signal conversion step of converting the video signal into a video signal. .