JPH08331470A - Multi-picture television receiver - Google Patents

Abstract

PURPOSE: To prevent picture omission from being generated by making the display positions of two compressed images mutually eccentric to a center and synthesizing those images while making overscan width equal with the time of one picture. CONSTITUTION: When a source image has the width of a video term of W2 corresponding to the display width of W1, a source image 1 is compressed to be [(1/2)+α)]-fold, another source image 2 is displayed on the left side, and the image compressed to be [(1/2)+α]-fold is similarly displayed on the right side. At such a time, when the overscan width is set equal with the time of one picture, two compressed images are displayed on the right side and left side while respectively getting over from the center of a display screen for W2, and the compressed images of [(1/2)+α]W2 are synthetically displayed while being overlapped just for 2αW2 at the center. Therefore, by suitably setting the value of α, at the time of displaying two pictures, a compression ratio is increased just for +α to the compression ratio while securing the required overscan width concerning two main and subordinate display pictures.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-screen television receiver which simultaneously displays a plurality of images.

[0002]

2. Description of the Related Art Conventionally, a multi-screen television receiver for displaying a plurality of television images side by side on one screen at a time has been
Video compression processing is performed at a compression ratio based on the required number of displays.

By the way, normally, in order to provide a margin for a screen loss due to a screen change, a video period of an original image to be projected with respect to an actual width of a display screen (for example, a screen of a cathode ray tube (CRT)). Is set to a larger width (so-called,
Therefore, when multiple TV images are horizontally divided and displayed, they are simply compressed at a compression ratio of 1 / display number and combined to maintain the same overscan width as that of one screen. Then, there is a problem that the overscan width occupied in the compressed images of the leftmost screen and the rightmost screen increases, and the ratio of missing information of the leftmost image and information of the rightmost image increases.

For example, when considering a two-screen television receiver that displays two television images side by side on one screen, both the main screen and the sub-screen are horizontally compressed to 1/2.

As shown in FIG. 7 (a), when the original image has a width of the video period of W2 with respect to the CRT display width of W1, the original image is compressed to ½ and the other one on the left side. When two different images are compressed to 1/2 and displayed on the right side, the compression ratio of the image has been selected to be 1/2. This is because by sub-sampling one sample for every two samples of the clock for sampling the original image, it can be easily compressed to 1/2.

As shown in FIG. 7 (b), when two screens are combined so that the screens are switched at the center of the display screen and they are displayed on one display screen, the same result as in FIG. 7 (a) is obtained. When scanning with horizontal overscan, the left screen is cut off at the left end, and the right screen is cut off at the right end. At this time, information loss occurs only at one end and the ratio of loss of the compressed screen is large, so that important information such as a telop may be lost.

In recent years, a large wide-screen receiver having an aspect ratio of 16: 9 has been commercially available. When such a television receiver displays as shown in FIG. 7 (b), the conventional picture-in Unlike picture TV receivers, they are displayed in the same size, so the lack of screen is noticeable, which gives a feeling of strangeness.

Therefore, as shown in FIG. 7 (c), by displaying the display positions of the images so that they are centered with respect to each other, the left and right information loss is equalized, and the information loss occurs only at one end. It is preventing.

However, in this case, as can be seen from FIG. 7 (c), the overscan width at the left and right edges of the screen is as shown in FIG.
It becomes half of that in the case of displaying the original image in (a), and in the case of display by CRT, the screen dropout easily occurs due to high-voltage fluctuation or display position fluctuation due to ghost.

As a countermeasure against this, a method of reducing the phase variation of the reproduction horizontal synchronization based on the high voltage variation of the CRT and the ghost can be considered, and the raster is 2W2 / (2) / () as it is in the image signal processing of the display of FIG. W1 + W2) times larger, and the overscan width may be the same as that in FIG. 7A. However, each method requires a large cost such as a change in the control circuit of the deflection system having a large power and a ghost removing circuit.

[0011]

As described above, in the conventional multi-screen television receiver, when the display positions of the images are centered with each other and combined, the left and right screen defects can be reduced, but the horizontal defects are reduced. The screen phase is likely to occur due to the synchronization phase fluctuation. Further, the method of reducing the phase fluctuation of the horizontal synchronization and the method of extending the raster have drawbacks that a large cost is required such as changing the control circuit of the deflection system with large power and a ghost removing circuit.

Therefore, the present invention can prevent information loss without requiring a large hardware change or a large cost increase, and can secure a necessary overscan width to prevent a screen loss due to a screen change. An object of the present invention is to provide a multi-screen television receiver that can prevent the occurrence.

[0013]

According to the first aspect of the present invention,
In a multi-screen television receiver that displays N (N is an integer of 2 or more) video signals in a multi-screen manner by horizontally dividing one display screen into equal parts, compresses horizontally ((1 / N) + α) In the ratio [0 <α <(1 / N)], N compression means for compressing N video signals respectively and N compressed video signals from the N compression means in the horizontal direction. When combining side by side, the horizontal overscan width when multi-screen display is made equal to the over-scan width when multi-screen display is not performed, and N pieces of images are overlapped by a predetermined width at the boundary portion adjacent to each other. And means for setting the display position timing of the compressed video signal on the display screen, and synthesizing means for synthesizing the N compressed video signals for which the display position timing has been set by this means.

According to a second aspect of the present invention, there is provided a multi-screen television receiver for displaying N (N is an integer of 2 or more) video signals on a single display screen in the horizontal direction in a multi-screen manner.
N A / D conversion means for A / D converting each of the video signals, N storage means for respectively storing the digital signals from the N A / D conversion means, and the N storages A write clock and a read clock are generated for each means to control writing and reading of each storage means, and the frequency ratio of the write clock and the read clock is ((1 / N) + α): 1 [ However, 0 <α <(1 / N)] is set to perform ((1 / N) + α) times the compression processing in the horizontal direction, and N compression processing is performed from the storage means. In order to control the read start timing at the time of reading each video signal, the horizontal overscan width when multi-screen display is made equal to the over-scan width when multi-screen display is not performed, and N A means for setting the display position timing of the N compressed video signals on the display screen and a display position timing from the N storage means are set so that the images are overlapped by a predetermined width at the boundary portions adjacent to each other. It is provided with N D / A converting means for respectively D / A converting the compressed video signals and a combining means for combining the outputs from the N D / A converting means.

According to a third aspect of the present invention, in a multi-screen television receiver for displaying two video signals on two screens by equally dividing one display screen in the horizontal direction, ((1/2) +
[wherein 0 <α <(1/2)] with a compression ratio of α), the first and second compression means compressing the first and second video signals respectively, and the first and second compression means. First and second from the means
When arranging the compressed video signals of and arranging them in the horizontal direction,
The first and second compressed images are set so that the horizontal overscan width when displaying two screens is equal to the overscan width when not displaying two screens and the two images are overlapped by a predetermined width at the boundary portions adjacent to each other. It is provided with a means for setting the display position timing of the signal on the display screen and a synthesizing means for synthesizing the first and second compressed video signals having the display position timing set by this means.

According to a fourth aspect of the present invention, in a multi-screen television receiver for displaying two video signals on two screens by equally dividing one display screen in the horizontal direction, each of the first and second video signals is A. First and second A / D conversion means for A / D conversion, first and second storage means for respectively storing digital signals from the first and second A / D conversion means, and the first and second storage means. , A write clock and a read clock are generated for each of the second storage means to control writing and reading of each storage means, and the frequency ratio of the write clock and the read clock is ((1/2) +
α): 1 [however, 0 <α <(1/2)] is set, and the control means for performing ((1/2) + α) times compression processing in the horizontal direction, and the first and second When controlling the read start timing when reading the compressed first and second compressed video signals from the storage means respectively, and when the horizontal overscan width when displaying two screens is not displaying two screens Means for setting the display position timings of the first and second compressed video signals on the display screen so that the first and second video images overlap each other by a predetermined width at the boundary portions adjacent to each other. And first and second D / A conversion means for respectively D / A converting the compressed video signals for which the display position timings have been set from the first and second storage means, and the first and second Combines outputs from D / A conversion means It is obtained by including a forming means.

According to a fifth aspect of the present invention, in a multi-screen television receiver that divides one display screen in the horizontal direction and displays two video signals on two screens, ((m / (m +
n)) + β) [where 0 <β <(m / (m
+ N)), m and n are positive numbers], and ((n / (m + n)) + γ) in the horizontal direction with the first compression means for compressing the first video signal.
With a compression ratio of [where 0 <γ <(n / (m + n)),
m and n are positive numbers], the second compression means for compressing the second video signal and the first and second compressed video signals from the first and second compression means are arranged in the horizontal direction and combined. At this time, the first and second areas are set so that the horizontal overscan width when multi-screen display is performed is equal to the over-scan width when multi-screen display is not performed, and two images are overlapped by a predetermined width at a boundary portion adjacent to each other. It is provided with a means for setting the display position timing of the compressed video signal on the display screen, and a synthesizing means for synthesizing the first and second compressed video signals having the display position timing set by this means.

The invention according to claim 6 has an aspect ratio of 1
In a multi-screen television receiver capable of multi-screen displaying at least two video signals with an aspect ratio of 4: 3 on one display screen of 6: 9 ((3/4) + β)
[Where 0 <β <(3/4)], a first compression means for compressing the first video signal and a compression ratio of ((1/4) + γ) in the horizontal direction [where , 0 <γ <(1
/ 4)]], when the second compression means for compressing the second video signal and the first and second compressed video signals from the first and second compression means are arranged in the horizontal direction and combined, The horizontal overscan width when the screen is displayed is equal to the overscan width when the multiscreen is not displayed, and 2
A unit for setting the display position timing of the first and second compressed video signals on the display screen so that the two images overlap with each other in a predetermined width at a boundary portion, and a unit for setting the display position timing by this unit. And a synthesizing means for synthesizing the first and second compressed video signals.

The invention according to claim 7 has an aspect ratio of 1
In a multi-screen television receiver capable of multi-screen displaying at least two video signals having an aspect ratio of 4: 3 on one display screen of 6: 9, the first and second video signals are respectively A / D converted. First and second A / D conversion means, first and second storage means for respectively storing digital signals from the first and second A / D conversion means, and the first and second storage means.
A write clock and a read clock are generated for each of the second storage means to write to each storage means,
In order to control the reading, the frequency ratio of the write clock and the read clock for the first storage means is ((3/4) + β): 1 [where 0 <β <(3
/ 4)], and performs a compression process of ((3/4) + β) times in the horizontal direction, and sets the frequency ratio of the write clock and the read clock to the second storage means to ((1/4)
+ Γ): 1 [however, 0 <γ <(1/4)] is set, and the control means performs compression processing of ((1/4) + γ) times in the horizontal direction, and the first and second When controlling the read start timing when reading the compressed first and second compressed video signals from the storage means respectively, and when the horizontal overscan width when displaying two screens is not displaying two screens Means for setting the display position timings of the first and second compressed video signals on the display screen so that the first and second video images overlap each other by a predetermined width at the boundary portions adjacent to each other. And first and second D / A conversion means for respectively D / A converting the compressed video signals for which the display position timings have been set from the first and second storage means, and the first and second Combines outputs from D / A conversion means It is obtained by and a combining means.

[0020]

According to the present invention as set forth in claims 1 and 2, when displaying N video screens in a horizontal direction with respect to one display screen, a simple compression ratio of 1 can be considered from the display number N at that time.
/ N is compressed by a compression ratio (1 / N) + α obtained by adding the required increase α (0 <α <1 / N), and the display positions of the compressed multiple images are centered with respect to each other. In addition, the overscan width is the same as in the case of one screen, so that multiscreen display is performed. By doing so, the required overscan width can be set by adding a relatively small amount of hardware without changing the horizontal deflection width of the CRT deflection system, and it is possible to prevent the screen from being chipped due to high-voltage fluctuations or ghosts of the CRT. At the same time, as the compression ratio is increased, the ratios of left chipping on the leftmost screen and right chipping on the rightmost screen can be reduced, and information loss in the central portions of the left and right screens can be reduced.

The present invention according to claims 3 and 4 is an example in which one display screen is divided into two parts to the left and right, and the sizes of the main and sub screens are made equal. The same effect as the invention according to claim 1 is obtained.

According to the fifth aspect of the present invention, when two images are horizontally divided into two at a ratio of m: n and displayed on one display screen, for example, the left screen ( (m
/ (M + n)) + β) and compress the right screen ((n
/ (M + n)) + γ) compressed at a compression ratio of 2
Two images are displayed by overlapping the display positions of one image beyond the boundary line and combining them with the overscan width being equal to that of one screen. In this way, C
The required overscan width can be set by adding relatively small hardware without changing the horizontal deflection width of the RT deflection system, and it is possible to prevent high-voltage fluctuations of the CRT and screen loss due to ghosts, and to reduce the compression ratio. As a result of the increase, it is possible to reduce the ratio of left missing on the left screen and right missing on the right screen, and it is possible to reduce the information missing at the center of each of the left and right screens.

The invention described in claims 6 and 7 is an example in which at least two images having an aspect ratio of 4: 3 are displayed on a display screen having an aspect ratio of 16: 9 as shown in FIG. 4 (b). . The same effect as the invention according to claim 1 is obtained.

[0024]

EXAMPLES Examples will be described with reference to the drawings. FIG. 1 is a block diagram showing a multi-screen television receiver according to an embodiment of the present invention. In the present embodiment, a two-screen television receiver that displays two television images side by side on one screen will be described.

In FIG. 1, the radio frequency (RF) television signal received by the antenna 11 is simultaneously input to the two tuners 12 and 15. Tuner 12, 15
Then, high frequency amplification (RF amplification), tuning, intermediate frequency (I
F) conversion, intermediate frequency amplification (IF amplification) and detection are performed, the tuner 12 outputs the composite color video signal of the channel selected as the main screen, and the tuner 15 outputs the composite color video signal of the channel selected as the sub screen. A composite color video signal is output and supplied to the video / chroma / synchronization processing circuits 13 and 16, respectively.
In the video / chroma / synchronization processing circuits 13 and 16, Y / C
Separation, color demodulation, and sync separation are performed, and R (red), G
The three primary color signals (green) and B (blue) and vertical and horizontal synchronizing signals are output. Vertical and horizontal synchronization signals obtained from the video / chroma / synchronization processing circuit 13 on the main screen side are supplied to the deflection circuit 20 and vertical and horizontal deflection currents are supplied to the deflection yoke 19a of the cathode ray tube (CRT) 19. .

Video / chroma / synchronization processing circuits 13 and 16
The R, G, and B signals output from ((1/2) + α) compression circuits 14 and 17 are ((1/2) + α) times (however, 0).
<Α <1/2), the display positions of the two compressed images are divided into left and right, and with the same overscan width as in the case of one screen, they are combined in the combining circuit 18 and displayed on the CRT 19. Is displayed.

FIG. 2 is a block diagram showing a concrete circuit example of the ((1/2) + α) compression circuits 14 and 17 in FIG.

In FIG. 2, the main screen signal input from the input terminal 141 is converted into a digital signal by the A / D converter 142. After that, a digital low-pass filter (LP
F) 144 is filtered and written in the memory 145 as a storage means. Sampling in the A / D converter 142 and writing to the memory 145 are performed using the clock CK1 supplied from the clock terminal 143. The main screen signal written in the memory 145 is compressed by ((1/2) + α) times using the clock CK2 from the clock input terminal 148, and the same clock CK2 is used for the D / A converter. After being converted into an analog signal in 147, it is output from the output terminal 149 to the synthesizing circuit 18. Here, if the frequency ratio of the clocks CK1 and CK2 input from the clock input terminals 143 and 148 is set to ((1/2) + α): 1, ((1/2) + α) times compression processing is performed. . The memory control circuit 146 is a means for setting the display position timing, and based on the vertical synchronizing signal VD and the horizontal synchronizing signal HD supplied to the input terminal 150, a timing signal for giving the horizontal reading start timing of the main screen. By supplying to the memory 145,
The display position timing of the main screen in the horizontal direction is given to the memory 145.

Similarly, also on the sub-screen side, the input terminal 1
The sub-screen signal input from 71 is the A / D converter 172.
Is converted into a digital signal by. After that, digital L
It is filtered by the PF 174 and written in the memory 175. Sampling in the A / D converter 172 and writing to the memory 175 are performed using the clock CK3 (= CK1) supplied from the clock terminal 173. The sub-screen signal written in the memory 175 is the clock CK4 (= CK2 from the clock input terminal 178).
((1/2) + α) times compression processing is performed by using the () and is converted into an analog signal by the D / A converter 177 using the same clock CK2, and then the combining circuit 18 is output from the output terminal 179.
Output to Clock input terminal 1 as on the main screen
Clocks CK3 and C respectively input from 73 and 178
If the frequency ratio of K4 is set to ((1/2) + α): 1 ((1 /
2) + α) times compression processing is performed. The memory control unit circuit 176 is means for setting the display position timing,
Based on the vertical synchronizing signal VD and the horizontal synchronizing signal HD supplied to the input terminal 150, a timing signal for giving a horizontal read start timing of the main screen is supplied to the memory 175, so that the main screen of the memory 175 is displayed. The display position timing in the horizontal direction is given.

The respective display position timings given from the memory control circuits 146, 176 to the memories 145, 175 based on the horizontal synchronizing signal HD are 2 when the overscan width is kept the same as one screen. It is controlled so that the display positions of the two images are centered on each other and overlapped by a predetermined width.

Next, with reference to FIG. 3, a display example of the screen displayed by the configuration of FIGS. 1 and 2 will be described.

FIG. 3 (a) shows original images 1 and 2 corresponding to the main screen and the sub screen, respectively, when the original image has a width of the video period of W2 with respect to the display width of W1. To ((1/2) +
Compress it to α) times, and on the left side, use another original picture 2 ((1/2) +
When it is compressed α times and displayed on the right side, it becomes as shown in Fig. 3 (b). At this time, if the overscan width is set to be the same as that for one screen (that is, FIG. 3A), it becomes 2
The two compressed images will be displayed with αW2 over to the right and left of the center line of the display screen.
In other words, the compressed images of width ((1/2) + α) W2 are overlapped and displayed by 2αW2 at the center. Therefore, by appropriately setting the value of α, when two screens are displayed, the compression ratio is increased by + α for the two main and sub display screens while ensuring the necessary overscan width. ), (C)), the compression ratio increases. For example, when looking at the left screen, the compressed image is displayed to the right of the center line by the amount that the compression ratio increases, so the ratio of the screen loss at the left edge of the left screen to the entire left screen (the ratio of the screen loss due to overscan) is calculated. Can be reduced.

In the above embodiment, since the compression processing of ((1/2) + α) times is performed only by changing the frequency ratio of the writing / reading of the memory, the horizontal deflection width etc. in the CRT deflection system with a large electric power, etc. Can be done without any changes, and it is easy to keep overscan the same as in the case of one screen.

In the above embodiment, the two-screen television receiver that displays two images of the same area in the horizontal direction on one display surface has been described, but the present invention is not limited to the two-screen television receiver. Generally, the present invention can be applied to a multi-screen television receiver that displays N images by equally dividing the display surface in the horizontal direction. When N images are displayed in this way, the compression ratio [(0 / α <0) is ((1 / N) + α) in the horizontal direction.
(1 / N)], the N video signals are compressed, and α is appropriately set so that the overscan width is made equal to that at the time of one-screen display and the two videos are overlapped by a predetermined width at the boundary portion adjacent to each other. By doing so, it is possible to reduce the information loss due to the left missing of the left screen and the right missing of the right screen, and to obtain the necessary information for each compressed screen.

FIG. 4 is a block diagram showing a multi-screen television receiver according to another embodiment of the present invention.

In this embodiment, for example, the aspect ratio is 16: 9.
6B shows an example of a multi-screen television receiver that displays four images with an aspect ratio of 4: 3 on the CRT as shown in FIG. 6 (b).
The same circuits as those in FIG. 1 are designated by the same reference numerals for description.

In the embodiment shown in FIG. 4, a video screen displayed on one display screen having an aspect ratio of 4: 3 is horizontally divided into two and displayed as a main screen.
The video screen of the first composite color video signal received by the tuner 12 and demodulated by the video / chroma / synchronization processing circuit 13 is horizontally ((3/4) + β) compression circuit 14A ((3 / 4) + β) at a compression ratio [however, 0
<Β <(3/4)] Compress. Also, the second screen, which is a sub screen
The video screen of the second composite color video signal received by the tuner 15 and demodulated by the video / chroma / synchronization processing circuit 16 is horizontally ((1/4) + γ) compression circuit 17A ((1 / 4) + γ) at the compression ratio [however, 0
<Γ <(1/4)] Compress. Similarly, the third and fourth video screens, which are sub-screens, show the third and fourth composite color video signals received by the tuners 21 and 24 and demodulated by the video / chroma / synchronization processing circuits 22 and 25. ,
At the compression ratio of ((1/4) + γ) in the horizontal direction in the ((1/4) + γ) compression circuits 23 and 26, [where 0 <γ <(1
/ 4)] Compress. The compression circuits 14A, 17A,
Reading from 23 and 26 is performed by the vertical sync signal VD and the horizontal sync signal HD from the video / chroma / sync processing circuit 13.
Is performed based on the display position timing (that is, the read start timing) obtained from At that time, the compression circuit 1
The starting positions in the horizontal direction of the compressed video signals read from 7A, 23, and 26 are the same as can be seen from FIG. 6 (b). The video signal compressed at the compression ratio of ((3/4) + β) from the compression circuit 14A and the three video signals compressed at the compression ratio of ((1/4) + γ) from the compression circuits 17A, 23, and 26. After being combined with the video signal by the combining circuit 18A, the CRT 19
Is supplied and displayed.

When considering the composite display of these four video signals, for the two main and sub video screens divided in the horizontal direction, the compressed video signal from the compression circuit 14A and the compression circuits 17A, 23, 26 are selected. For example, regarding the compressed video signal from the compression circuit 23, the first video signal compressed ((3/4) + β) times and the second video signal compressed ((1/4) + γ) times The video signal and the overscan width is 1
The same image as that on the screen is kept, and the images of both are overlapped with each other by a predetermined width at the boundary portion and are combined and displayed.

FIG. 5 shows the compression circuits 14A, 1 in FIG.
7A, 23 and 26 are shown. Circuits having the same configurations as those in FIG. 2 are denoted by the same reference numerals. Regarding the compression circuit 23,
Reference numerals 231 to 239 denote the respective circuits, and the compression circuit 26 is represented by the reference numerals 261 to 269. The frequencies of the write clocks CK1, CK3, CK5, CK7 in the compression circuits 14A, 17A, 23, 26 are all the same, and the frequencies of the read clocks CK4, CK6, CK8 in the compression circuits 17A, 23, 26 are all the same.

The frequency ratio between the write clock CK1 and the read clock CK2 in the compression circuit 14A is
((3/4) + β): 1 is set, and the compression circuits 17A, 2
Write clocks CK3 (= CK5 =
CK7) and read clock CK4 (= CK6 = CK8
The frequency ratio with () is set to ((1/4) + γ): 1.

FIG. 6 shows a display example in the embodiment of FIG. This embodiment is a CRT with an aspect ratio of 16: 9.
Shows an example of displaying four images with an aspect ratio of 4: 3. However, for the sake of simplicity, in this example, for the one-fourth compressed right screen, only one screen in the center in the vertical direction is described. To do.

FIG. 6 (a) shows original images 1 and 2 corresponding to the main screen and the sub screen, respectively, when the original image has a width of the video period of W2 with respect to the display width of W1. To ((3/4) +
When the original image 2 is compressed (β) times to the left side and another original image 2 is compressed to ((1/4) + γ) times and displayed to the right side, it becomes as shown in FIG. 6 (b). At this time, the overscan width is set to one screen (that is,
If set to be the same as in Fig. 6 (a), the two compressed images will have the original boundary line of the display screen (width 3 shown by the solid line).
It is displayed with βW2 over to the right and γW2 over to the left of the boundary line between W2 / 4 and width W2 / 4). That is, the compressed image of width ((3/4) + β) W2 and the compressed image of width ((1/4) + γ) W2 are (β + γ) W2 on both sides of the original boundary line (line indicated by the solid line). It will be overlapped and displayed in a composite manner. Therefore, by appropriately setting the values of β and γ, when the four-screen display of 4: 3 is performed, the compression ratio is increased by + β and + γ while securing the necessary overscan width for the main and sub display screens. Only, the compression ratio can be increased as compared with the conventional 4-screen display.
For example, when looking at the left screen, the compressed image is displayed on the right side of the boundary line by the amount of increase in the compression ratio, so the ratio of the screen loss at the left edge of the left screen to the entire left screen (the rate of screen loss due to overscan) is calculated. Can be reduced.

Also in the embodiment of FIG. 4, ((3/4) + β)
Double ((1/4) + γ) times compression processing can be performed only by changing the write / read frequency ratio of each memory for main and sub memory, so there is no need to change the horizontal deflection width in the CRT deflection system. It is easy to keep the overscan width the same as in the case of one screen.

In the embodiment shown in FIG. 4, a multi-screen television receiver for displaying two images compressed at a ratio of 3: 1 in the horizontal direction on one display surface has been described. Not only when compressing a video signal in the horizontal direction at a ratio of 3: 1, one video signal in the horizontal direction is ((m / (m + n)) +
At a compression ratio of β, [where 0 <β <(m / (m +
n)), m and n are positive numbers], and another video signal is compressed in the horizontal direction at a compression ratio of ((n / (m + n)) + γ) [where 0 <γ <(n / (m + n )), M and n are positive numbers], and β and γ are appropriately set so that the compression is performed, the overscan width is made equal to that at the time of single-screen display, and two images are overlapped by a predetermined width at a boundary portion adjacent to each other. As a result, it is possible to reduce the information loss due to the left missing part of the left screen and the right missing part of the right screen to obtain the necessary information for each compressed screen.

[0045]

As described above, according to the present invention, when a plurality of television images are displayed on one screen in a multi-screen,
While it is possible to prevent missing information on the left and right display screens,
It is possible to secure the necessary overscan width and prevent the occurrence of a screen loss due to the fluctuation of the reproduced sync phase. In addition, it can be realized without requiring a large hardware change or a large cost increase.

[Brief description of drawings]

FIG. 1 is a block diagram showing a multi-screen television receiver according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a compression circuit in FIG.

FIG. 3 is a diagram showing a display example in the embodiment of FIG.

FIG. 4 is a block diagram showing a multi-screen television receiver according to another embodiment of the present invention.

5 is a block diagram showing a configuration example of a compression circuit in FIG.

FIG. 6 is a diagram showing a display example in the embodiment of FIG.

FIG. 7 is a diagram showing a conventional display example.

[Explanation of symbols]

12, 16 ... Video / chroma / synchronization processing circuit 14, 17 ... ((1/2) + α) compression circuit 18 ... Synthesis circuit 19 ... CRT 146, 176 ... Memory control circuit (means for setting display position timing)

Claims (7)

[Claims] 1. A display screen is divided into N equal parts in the horizontal direction.
In a multi-screen television receiver that displays a plurality (N is an integer of 2 or more) of video signals on a multi-screen, at a compression ratio of ((1 / N) + α) in the horizontal direction, [0
<Α <(1 / N)], N compression means for respectively compressing N video signals, and N compression video signals from the N compression means are arranged in the horizontal direction to be synthesized. In order to make the horizontal overscan width when displayed on the screen equal to the overscan width when not displayed on multiple screens and to overlap the N images by a predetermined width at the boundary portions adjacent to each other, the N compressed video signals are A multi-screen television receiver comprising: a means for setting a display position timing on a display screen; and a synthesizing means for synthesizing N compressed video signals having the display position timing set by the means. 2. A display screen is equally divided horizontally into N display screens.
In a multi-screen television receiver that displays a plurality of (N is an integer of 2 or more) video signals on a multi-screen, N A / Ds for A / D converting each of the N video signals
Conversion means, N storage means for respectively storing the digital signals from the N A / D conversion means, and a write clock and a read clock for each of the N storage means, and each storage means The write / read control is performed by setting the frequency ratio of the write clock and the read clock to ((1 / N) +
α): 1 [however, 0 <α <(1 / N)] is set, and the compression process is performed from the storage unit by a control unit that performs a compression process of ((1 / N) + α) times in the horizontal direction. It controls the read start timing when each of the N compressed video signals is read, and makes the horizontal overscan width when multiscreen display is made equal to the overscan width when not multiscreen display and N A unit for setting the display position timing of the N compressed video signals on the display screen and a display position timing from the N storage units so that the plurality of images overlap each other by a predetermined width at the boundary portions. N D / s for D / A converting each compressed video signal
A multi-screen television receiver characterized by comprising A conversion means and combining means for combining the outputs from the N D / A conversion means. 3. A display screen is divided equally into two horizontally.
In a multi-screen TV receiver that displays two video signals on two screens, the compression ratio becomes ((1/2) + α) in the horizontal direction.
<Α <(1/2)], first and second compression means for compressing the first and second video signals, respectively, and first and second compression means from the first and second compression means. When arranging and synthesizing video signals in the horizontal direction, the horizontal overscan width when displaying two screens is made equal to the overscan width when not displaying two screens, and the two images overlap each other by a predetermined width at the boundary portion adjacent to each other. So that the display position timing of the first and second compressed video signals on the display screen is set, and the first and second display position timings are set by this means.
And a synthesizing means for synthesizing the compressed video signal of 1. 4. A display screen is divided equally into two horizontally.
In a multi-screen television receiver that displays two video signals on two screens, the first and second video signals are respectively A / D converted.
Second A / D conversion means, first and second storage means for respectively storing the digital signals from the first and second A / D conversion means, and the first and second storage means A write clock and a read clock are generated for each, and writing and reading of each storage unit are controlled. The frequency ratio of the write clock and the read clock is ((1/2)).
+ Α): 1 [however, 0 <α <(1/2)] is set to perform a compression process of ((1/2) + α) times in the horizontal direction, and the first and second When controlling the read start timing when reading the compressed first and second compressed video signals from the storage means respectively, and when the horizontal overscan width when displaying two screens is not displaying two screens Means for setting the display position timings of the first and second compressed video signals on the display screen so that the first and second video images overlap each other by a predetermined width at the boundary portions adjacent to each other. And first and second D / A conversion means for respectively D / A converting the compressed video signals for which the display position timings from the first and second storage means are set, and the first and second Output from D / A converter is combined Multi-screen television receiver characterized by comprising a combining means that. 5. In a multi-screen television receiver that horizontally divides one display screen and displays two video signals on two screens, a horizontal compression ratio ((m / (m + n)) + β) However, 0 <β <(m / (m + n)), m and n are positive numbers], the first
With a first compression means for compressing the video signal of (1) and a compression ratio of ((n / (m + n)) + γ) in the horizontal direction [where 0 <γ <(n / (m + n)), where m and n are positive. Number], second
Second compression means for compressing the video signal of No. 1 and the first and second compressed video signals from the first and second compression means are arranged side by side in the horizontal direction and are combined in the horizontal direction when multi-screen display is performed. Display of the first and second compressed video signals on the display screen so that the overscan width is equal to the overscan width when multi-screen display is not performed and the two video images overlap each other by a predetermined width at a boundary portion adjacent to each other. Means for setting position timing, and first and second display position timing set by this means
And a synthesizing means for synthesizing the compressed video signal of 1. 6. A multi-screen television receiver capable of multi-screen displaying at least two video signals having an aspect ratio of 4: 3 on one display screen having an aspect ratio of 16: 9, in a horizontal direction ((3 / 4) + β) at a compression ratio [however, 0
<Β <(3/4)], a first compression means for compressing the first video signal, and a compression ratio of ((1/4) + γ) in the horizontal direction [however, 0
<Γ <(1/4)], second compression means for compressing the second video signal, and the first and second compressed video signals from the first and second compression means are arranged in the horizontal direction. At the time of synthesizing, the horizontal overscan width in the multi-screen display is made equal to the overscan width in the non-multi-screen display, and the two images are overlapped by a predetermined width at the boundary portions adjacent to each other. Means for setting the display position timing of the second compressed video signal on the display screen, and first and second means for setting the display position timing by this means.
And a synthesizing means for synthesizing the compressed video signal of 1. 7. A multi-screen television receiver capable of multi-screen displaying at least two video signals having an aspect ratio of 4: 3 on one display screen having an aspect ratio of 16: 9. The first and the A / D conversion of each signal
Second A / D conversion means, first and second storage means for respectively storing the digital signals from the first and second A / D conversion means, and the first and second storage means A write clock and a read clock are generated for each, and writing and reading of each storage unit are controlled.
The frequency ratio between the write clock and the read clock for the storage means is ((3/4) + β): 1 [where 0
<Β <(3/4)], and set ((3/4)
+ Β) times compression processing is performed, and the frequency ratio between the write clock and the read clock for the second storage means is
((1/4) + γ): 1 [where 0 <γ <(1 /
4)] to perform ((1/4) + γ) times the compression processing in the horizontal direction, and the first and second compression processing compressed from the first and second storage means. This is for controlling the read start timing when each of the video signals is read, and the horizontal overscan width when displaying two screens is made equal to the overscan width when not displaying two screens. Means for setting the display position timing of the first and second compressed video signals on the display screen so that the images overlap each other by a predetermined width at the boundary portions adjacent to each other; and the display from the first and second storage means. First and second D / A converting means for respectively D / A converting the compressed video signals with position timing set, and a combining means for combining the outputs from the first and second D / A converting means It is equipped with And a multi-screen TV receiver.